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1

A New Seafloor Spreading Model of the Red Sea: Magnetic Anomalies and Plate Kinematics  

NASA Astrophysics Data System (ADS)

A high resolution aeromagnetic survey over the Saudi Arabian side of the Red Sea confirms the existence of consistent magnetic anomaly patterns, continuous from 16 to 24°N, and episodic up to 28°N, typical of slow to ultraslow spreading centers. The older Saudi-Sudanese aeromagnetic survey shows that these anomalies are symmetrical between 18 and 23°N. The strong, short-wavelength anomalies over the central trough south of 24°N have long been identified as Chrons 1 to 3 (0-5 Ma). By contrast, the weaker, longer-wavelength anomalies over adjacent sediment-covered areas do not fit standard magnetic anomaly models. The abrupt basement deepening from ~ 1.5 km in the central trough to ~ 5 km beneath the sediments partly accounts for the lower amplitude but not for the lack of short wavelengths. Other spreading centers also lack short-wavelength, high-amplitude magnetic anomalies where covered by thick sediments (Andaman Basin, Juan de Fuca Ridge). We interpret this to reflect the absence of a well-defined layer of pillow lavas, whose emplacement is hampered by rapid, abundant sedimentation. The formation of dykes and sills instead of extrusive lavas results in weaker, less coherent magnetization, generating longer-wavelength anomalies. We test this inference by removing the extrusive basalt contribution from a slow spreading center crustal magnetization model. The computed magnetic anomalies fit well with the shape and amplitude of the anomalies observed in the Red Sea. Two major long-wavelength anomalies are dated at 10-11 Ma (Chron 5) and 14-15 Ma (Chron 5B), implying seafloor spreading back to at least 15 Ma and constraining plate-kinematic reconstructions. Beyond being a key to the geological evolution of the Red Sea, these results emphasize that oceanic crust may exist without clear, short wavelength magnetic anomalies, particularly at the onset of seafloor spreading, when abundant sedimentation may preclude the formation of pillow lavas. The location of many inferred ocean-continent boundaries, particularly beneath thick evaporite sequences, should therefore be revisited, alleviating the need for 'transitional' crust and allowing for a tighter fit of continents in initial reconstructions.

Dyment, J.; Tapponnier, P.; Afifi, A. M.; Zinger, M. A.; Franken, D.; Muzaiyen, E.

2013-12-01

2

Early India-Australia Spreading History Revealed by Newly Detected Magnetic Anomalies  

NASA Astrophysics Data System (ADS)

The seafloor within the Perth Abyssal Plain (PAP), offshore Western Australia, is the only section of crust that directly records the early spreading history between India and Australia during the Mesozoic breakup of Gondwana. However, this early spreading has been poorly constrained due to an absence of data, including marine magnetic anomalies and data constraining the crustal nature of key tectonic features. Here, we present new magnetic anomaly data from the PAP that shows that the crust in the western part of the basin was part of the Indian Plate - the conjugate flank to the oceanic crust immediately offshore the Perth margin, Australia. We identify a sequence of M2 and older anomalies in the west PAP within crust that initially moved with the Indian Plate, formed at intermediate half-spreading rates (35 mm/yr) consistent with the conjugate sequence on the Australian Plate. More speculatively, we reinterpret the youngest anomalies in the east PAP, finding that the M0-age crust initially formed on the Indian Plate was transferred to the Australian Plate by a westward jump or propagation of the spreading ridge shortly after M0 time. Samples dredged from the Gulden Draak and Batavia Knolls (at the western edge of the PAP) reveal that these bathymetric features are continental fragments rather than igneous plateaus related to Broken Ridge. These microcontinents rifted away from Australia with Greater India during initial breakup at ~130 Ma, then rifted from India following the cessation of spreading in the PAP (~101-103 Ma).

Williams, S.; Whittaker, J. M.; Granot, R.; Müller, D.

2013-12-01

3

Investigation of spreading center ecolution by joint inversion of seafloor magnetic anomaly and tectonic fabric data  

NASA Technical Reports Server (NTRS)

Spreading center segments that have experienced a complex tectonic history including rift propagation may have a complicated signature in bathymetric and magnetic anomaly data. To gain insight into the history of such regions, we have developed techniques in which both the magnetic anomaly patterns and seafloor fabric trends are predicted theoretically, and the combined predictions are compared numerically with the data to estimate best fitting parameters for the propagation history. Fitting functions are constructed to help determine which model best matches the digitized fabric and magnetic anomaly data. Such functions offer statistical criteria for choosing the best fit model. We use this approach to resolve the propagation history of the Cobb Offset along the Juan de Fuca ridge. In this example, the magnetic anomaly data prove more useful in defining the geometry of the propagation events, while the fabric, with its greater temporal resolution, is more useful for constraining the rate of propagation. It thus appears that joint inversion of magnetic and seafloor fabric data can be valuable in tectonic analyses.

Shoberg, Tom; Stein, Seth

1994-01-01

4

Opening of the Gulf of Mexico and the Nature of the Crust in the Deep Gulf: New Evidence from Seafloor Spreading Magnetic Anomalies  

NASA Astrophysics Data System (ADS)

The seafloor spreading history in the Gulf of Mexico is poorly constrained due to a lack of recognized seafloor spreading magnetic anomalies, a paucity of deep penetrating seismic data, and absence of drilling to constrain crystalline ocean floor composition and ages. We have identified lineated magnetic anomalies in the eastern Gulf on profiles collected during the Woods Hole R/V Farnella FRNL85-2 cruise that correlate with magnetic chrons M21R to M10. Forward modeling shows that these anomalies formed during creation of weakly magnetized new seafloor in the eastern Gulf between 149-134 Ma at an average half-spreading rate of 3.2 cm/yr. The oldest anomalies are located against stretched continental crust beneath the western Florida shelf on the east and the Yucatan shelf on the west. The youngest anomalies form a juxtaposed conjugate pair that mark the location of an extinct spreading ridge between Yucatan and Florida. Seismic velocities of the crust in the eastern Gulf and the amplitude of the magnetic anomalies are similar to the Iberian and Newfoundland rifted margins, where the early stages of continental breakup were accommodated by exhumation of subcontinental lithosphere rather than creation of new basaltic oceanic crust. We infer that the eastern Gulf of Mexico is underlain by exhumed sub-continental peridotitic mantle intruded by lesser volumes of basaltic igneous rocks generated by decompression melting of the asthenosphere during the late stages of opening of the Gulf. The long wavelength characteristics of the magnetic and gravity fields in the eastern Gulf, as well as the seismic velocity structure of the crust, differ from those in the central and western Gulf, which are more similar to typical magmatic rifted margins. This suggests that the character of the Gulf changes along strike, from a magmatic western portion to an amagmatic eastern portion. Paleogeographic restoration of the lineated magnetic anomaly pattern suggests a 4-phase model for opening of the Gulf. During phase 1 (Early Permian-Late Triassic), Yucatan and associated tectonic blocks that now comprise eastern Mexico were translated eastward from the Pacific realm into positions near the modern western Gulf. During phase 2 (Late Triassic-ca. 160 Ma) Yucatan and the South Florida block were translated southeastward relative to North America, rotating 6.7? counterclockwise about a pole located at 34?N, 74?W. This resulted in ca. 430 km of southeastward extension on the North American coastal plain, 120 km of southward extension on the northern Yucatan shelf, and displacement of the South Florida Block from a pre-rift position on the northwest Florida shelf to its modern position. During phase 3 (ca. 160-149 Ma), Yucatan rotated counterclockwise 46? relative to North America about a pole located at 27.6?N, 84.0?W. Phase 3 may have coincided with seafloor spreading in the central and western Gulf, but predated seafloor spreading in the eastern Gulf. During phase 4 (149-134 Ma), Yucatan moved southwestward relative to North America, rotating counterclockwise 2.2? about a pole located at 17.6?N, 74.2?W and completing opening of the Gulf.

Harry, D. L.; Eskamani, P. K.

2013-12-01

5

Filtering Marine Magnetic Anomalies  

Microsoft Academic Search

When marine magnetic anomalies can be adequately modeled by two-dimensional magnetic structures within one or more plane layers, many interesting manipulations of both models and anomalies are linear filtering operations [Dean, 1958; Bott, 1967; Black and Scollar, 1969; Schouten, 1971]. Linear filters can be applied quickly and accurately by using the fast Fourier transform algorithm [Cooley and Tukey, 1965]. We

Hans Schouten; Keith McCamy

1972-01-01

6

Updated interpretation of magnetic anomalies and seafloor spreading stages in the South China Sea - Implications for the Tertiary tectonics of Southeast Asia  

Microsoft Academic Search

An updated interpretation of the magnetic data of the South China Sea is presented, and its implications for the evolution of the South China Sea spreading ridge are discussed. A new identification of magnetic lineations in the basin is described. The kinematic parameters of spreading are then computed from the fit of the magnetic isochrons, and the characteristics of the

Anne Briais; Philippe Patriat; Paul Tapponnier

1993-01-01

7

Methods used to identify seafloor spreading magnetic anomalies and to establish their relationship with the top of the basement topography in the Argentine continental margin between 35° S and 48° S  

NASA Astrophysics Data System (ADS)

This paper discusses some methods for better identification of the spreading seafloor magnetic anomalies in the region between 35° S and 48° S at the outer edge of the continental margin of Argentina. In the area of Rio de la Plata craton and Patagonia Argentina, there is an extensional volcanic passive margin. This segment of the Atlantic continental margin is characterized by the existence of seismic reflectors sequences that lean toward the sea (seaward dipping reflectors - SDRs). These sequences of seismic reflectors, located in the transitional-continental basement wedge, are portrayed in seismic profiles as an interference pattern interpreted as basalt flows intercalated with sedimentary layers, and its origin is ascribed to volcanism occurred during the Early Cretaceous. The magnetic response of SDRs is in the area of the magnetic anomaly G (Rabinowitz and LaBrecque, 1979). Magnetic alignments are highlighted on a map by superimposing total field anomaly semitransparent layer of calculated numerical curvature. This method allows a regional identification of the most prominent alignments. It is convenient to calculate the curvature in the direction perpendicular to the magnetic alignments. The identification of seafloor spreading magnetic anomalies located in the eastern margin helps in the knowledge of the history of the Atlantic Ocean opening. M series magnetic alignments: M5n, M3n M0r (between 132 and 120 Ma) were identified in the analyzed area. The roughness of the top of the oceanic basement presents a contrast of amplitudes, in a wavelength range between about 4 km and 6 km, with the corresponding amplitudes in the area of the transitional crust. This contrast of amplitudes can be detected using spectral methods, especially short Fourier transform. The quantitative evaluation of the spectral energy density allowed the identification of wave numbers characterizing oceanic basement area and thus perform subsequent filtering of the signal with wavelengths found with the spectral method. The top of basement roughness was quantified using the root mean square (RMS), in sections of about 2 km, of residues between the depth of the basement top and first-degree polynomial that best fitted the sections. The spreading seafloor magnetic alignments are on oceanic crust area identified by the point of view of the roughness analysis. The combined use of the methods that we have developed on the magnetic surveys in the study area, allowed us to improve the layout of the magnetic alignments and identify the transition between oceanic and continental crust.

Abraham, D. A.; Ghidella, M. E.; Tassone, A.; Paterlini, M.; Ancarola, M.

2013-05-01

8

Magnetic Anomalies over Iceland  

Microsoft Academic Search

An aeromagnetic survey of Iceland reveals broad anomalies of large amplitude over zones of recent volcanic activity. The source of the anomalies is ascribed to large masses of basalt that have been coherently remagnetized by intrusive heating. A simple correlation of the Icelandic anomalies with those of the ocean floor therefore appears unjustified.

P. H. Serson; W. Hannaford; G. V. Haines

1968-01-01

9

Magnetic Anomalies over Iceland.  

PubMed

An aeromagnetic survey of Iceland reveals broad anomalies of large amplitude over zones of recent volcanic activity. The source of the anomalies is ascribed to large masses of basalt that have been coherently remagnetized by intrusive heating. A simple correlation of the Icelandic anomalies with those of the ocean floor therefore appears unjustified. PMID:17836657

Serson, P H; Hannaford, W; Haines, G V

1968-10-18

10

Implications for the South Atlantic early breakup and seafloor spreading from joint interpretation of magnetic anomaly maps and seaward-dipping reflector sequences (SDRS) visible in conjugated reflection seismic sections  

NASA Astrophysics Data System (ADS)

The late history of the South Atlantic passive margin evolution is investigated in the view of interlaced magnetic anomalies related to seafloor spreading lineations and anomalies caused by seaward-dipping reflector sequences (SDRS). Our identification of previously unknown pre-M5n lineations in marine magnetic data offshore Argentina now makes the lineation pattern more complete and most importantly comparable and nearly symmetrical to the conjugated area offshore South Africa. Therefore, we can now compare several sets of published South Atlantic reconstruction poles to our new pre-M5n lineations off Argentina and their equivalents off South Africa. The analysis of the symmetry of SDRS and particularly of their along-margin extension further constrains the choice of possible reconstruction poles for the earliest opening phases. The interpretation of pre-M5n lineations also defines the exact time (M9r) of the termination of excess breakup related volcanic activity and the transition to "normal" seafloor spreading. This is compared to absolute radiometric ages from Parana/Etendeka flood basalts. The volcanic activity related to the southernmost volcanic margin segments falls approximately into the same time window as the continental flood basalt activity. Unfortunately, more detailed conclusions suffer seriously from an ongoing discussion about the absolute ages of the pre-M0r lineations in different versions of polarity timescales. New models for the magnetic response of SDRS reveal a high variability within the wedges on either side of the Atlantic and between the conjugated margins. Former identifications of anomaly M11r off Cape Town have already been questioned and can now be shown to be caused by structural or magnetization variations within SDRS.

Schreckenberger, Bernd; Koopmann, Hannes; Franke, Dieter; Schnabel, Michael

2013-04-01

11

A global magnetic anomaly map  

NASA Technical Reports Server (NTRS)

A subset of Pogo satellite magnetometer data has been formed that is suitable for analysis of crustal magnetic anomalies. Through the use of a thirteenth-order field model fit to these data, magnetic residuals have been calculated over the world to latitude limits of plus or minus 50 deg. These residuals, averaged over 1-degree latitude-longitude blocks, represent a detailed global magnetic anomaly map derived solely from satellite data. The occurrence of these anomalies on all individual satellite passes independent of local time and their decay as altitude increases imply a definite internal origin. Their wavelength structure and their correlation with known tectonic features further suggest that these anomalies are primarily of geologic origin and have their sources in the lithosphere.

Regan, R. D.; Davis, W. M.; Cain, J. C.

1975-01-01

12

Binning of satellite magnetic anomalies  

NASA Technical Reports Server (NTRS)

Crustal magnetic anomaly signals over satellite orbits were simulated to investigate numerical averaging as an anomaly estimator. Averaging as an anomaly estimator involves significant problems concerning spatial and amplitude smoothing of the satellite magnetic observations. The results of simulations suggest that the error of numerical averaging constitutes a small and relatively minor component of the total error-budget of higher orbital anomaly estimates, whereas for lower orbital estimates numerical averaging error increases substantially. As an alternative to numerical averaging, least-squares collocation was investigated and observed to produce substantially more accurate anomaly estimates, particularly as the orbital elevation of prediction was decreased towards the crustal sources. In contrast to averaging, collocation is a significantly more resource-intensive procedure to apply because of the practical, but surmountable problems related to establishing and inverting the covariance matrix for accurate anomaly prediction. However, collocation may be much more effectively used to exploit the anomaly details contained in the lower orbital satellite magnetic data for geologic analysis.

Goyal, H. K.; Vonfrese, R. R. B.; Hinze, W. J.

1985-01-01

13

A Global Magnetic Anomaly MAP.  

National Technical Information Service (NTIS)

A subset of POGO satellite magnetometer data has been formed that is suitable for analysis of crustal magnetic anomalies. Using a thirteenth order field model, fit to these data, magnetic residuals have been calculated over the world to latitude limits of...

R. D. Regan W. M. Davis J. C. Cain

1974-01-01

14

Spreading rate dependence of gravity anomalies along oceanic transform faults.  

PubMed

Mid-ocean ridge morphology and crustal accretion are known to depend on the spreading rate of the ridge. Slow-spreading mid-ocean-ridge segments exhibit significant crustal thinning towards transform and non-transform offsets, which is thought to arise from a three-dimensional process of buoyant mantle upwelling and melt migration focused beneath the centres of ridge segments. In contrast, fast-spreading mid-ocean ridges are characterized by smaller, segment-scale variations in crustal thickness, which reflect more uniform mantle upwelling beneath the ridge axis. Here we present a systematic study of the residual mantle Bouguer gravity anomaly of 19 oceanic transform faults that reveals a strong correlation between gravity signature and spreading rate. Previous studies have shown that slow-slipping transform faults are marked by more positive gravity anomalies than their adjacent ridge segments, but our analysis reveals that intermediate and fast-slipping transform faults exhibit more negative gravity anomalies than their adjacent ridge segments. This finding indicates that there is a mass deficit at intermediate- and fast-slipping transform faults, which could reflect increased rock porosity, serpentinization of mantle peridotite, and/or crustal thickening. The most negative anomalies correspond to topographic highs flanking the transform faults, rather than to transform troughs (where deformation is probably focused and porosity and alteration are expected to be greatest), indicating that crustal thickening could be an important contributor to the negative gravity anomalies observed. This finding in turn suggests that three-dimensional magma accretion may occur near intermediate- and fast-slipping transform faults. PMID:17625563

Gregg, Patricia M; Lin, Jian; Behn, Mark D; Montési, Laurent G J

2007-07-12

15

An Interpretation of the Seafloor Spreading History of the West Enderby Basin between Initial Breakup of Gondwana and Anomaly C34  

Microsoft Academic Search

The seafloor spreading evolution in the Southern Indian Ocean is key to understanding the initial breakup of Gondwana. We summarize the structural lineaments deduced from the GEOSAT 10?Hz sampled raw altimetry data as well as satellite derived gravity anomaly map and the magnetic anomaly lineation trends from vector magnetic anomalies in the West Enderby Basin, the Southern Indian Ocean. The

Yoshifumi Nogi; Kumiko Nishi; Nobukazu Seama; Yoichi Fukuda

2004-01-01

16

Satellite magnetic anomalies over subduction zones - The Aleutian Arc anomaly  

NASA Technical Reports Server (NTRS)

Positive magnetic anomalies seen in MAGSAT average scalar anomaly data overlying some subduction zones can be explained in terms of the magnetization contrast between the cold subducted oceanic slab and the surrounding hotter, nonmagnetic mantle. Three-dimensional modeling studies show that peak anomaly amplitude and location depend on slab length and dip. A model for the Aleutian Arc anomaly matches the general trend of the observed MAGSAT anomaly if a slab thickness of 7 km and a relatively high (induced plus viscous) magnetization contrast of 4 A/m are used. A second source body along the present day continental margin is required to match the observed anomaly in detail, and may be modeled as a relic slab from subduction prior to 60 m.y. ago.

Clark, S. C.; Frey, H.; Thomas, H. H.

1985-01-01

17

Magnetic anomalies in the Eastern Caribbean  

NASA Astrophysics Data System (ADS)

Despite the many different studies on the origin and evolution of the Caribbean Plate, no proposal has been widely accepted so far. A key element within this field of research is the characterization of the plate subsurface oceanic crust, as it would clarify the conditions in which it originated, the geological period when it formed and its possible geographical location at this first evolution stage. Based on partial results of this research work, we can say that the conclusions of previous studies are valid to a great extent, namely the NE-SW orientation of the striped magnetic anomalies in the Venezuelan Basin's western section and the existence of W-E preferentially oriented stripes parallel to the Leeward Antilles. The magnetic response of the triangular section in the southeast of the Venezuelan Basin represents cretaceous magnetic quiet zone (CMQZ) and therefore shows a considerable attenuation of the stripe pattern, indicating that the whole East Caribbean subsurface features oceanic crustal material. As for the period recorded by the Caribbean magnetic stripes, we propose the interval between chrons M23 and M0, and part of CMQZ. The wavelengths of the identified anomalies suggest that the ridge associated with the formation of Caribbean ocean floor was slow-spreading when compared to average currently active ridges.

Orihuela Guevara, Nuris; García, Andreína; Arnaiz, Mariano

2013-04-01

18

Spectral Methods for Magnetic Anomalies  

NASA Astrophysics Data System (ADS)

Spectral methods, that is, those based in the Fourier transform, have long been employed in the analysis of magnetic anomalies. For example, Schouten and MaCamy's Earth filter is used extensively to map patterns to the pole, and Parker's Fourier transform series facilitates forward modeling and provides an efficient algorithm for inversion of profiles and surveys. From a different, and perhaps less familiar perspective, magnetic anomalies can be represented as the realization of a stationary stochastic process and then statistical theory can be brought to bear. It is vital to incorporate the full 2-D power spectrum, even when discussing profile data. For example, early analysis of long profiles failed to discover the small-wavenumber peak in the power spectrum predicted by one-dimensional theory. The long-wavelength excess is the result of spatial aliasing, when energy leaks into the along-track spectrum from the cross-track components of the 2-D spectrum. Spectral techniques may be used to improve interpolation and downward continuation of survey data. They can also evaluate the reliability of sub-track magnetization models both across and and along strike. Along-strike profiles turn out to be surprisingly good indicators of the magnetization directly under them; there is high coherence between the magnetic anomaly and the magnetization over a wide band. In contrast, coherence is weak at long wavelengths on across-strike lines, which is naturally the favored orientation for most studies. When vector (or multiple level) measurements are available, cross-spectral analysis can reveal the wavenumber interval where the geophysical signal resides, and where noise dominates. One powerful diagnostic is that the phase spectrum between the vertical and along-path components of the field must be constant 90 degrees. To illustrate, it was found that on some very long Project Magnetic lines, only the lowest 10% of the wavenumber band contain useful geophysical signal. In this case the spectra and cross spectra show that the source of the noise is instability in the gyro platform. Spectral techniques should always be applied to vector data in order to avoid overinterpretation of short-wavelength features.

Parker, R. L.; Gee, J. S.

2013-12-01

19

43. Magnetic Anomalies and Sea-Floor Spreading in the Western North Atlantic, and a Revised Calibration of the Keathley (M) Geomagnetic Reversal Chronology.  

National Technical Information Service (NTIS)

The very detailed body of data on ocean crust magnetism in the western North Atlantic has been reviewed and updated. In the last 5 to 10 years this body of data has grown somewhat, but the principal revisions in our understanding of the North Atlantic hav...

P. R. Vogt A. M. Einwich

1979-01-01

20

Regional magnetic anomaly constraints on continental rifting  

NASA Technical Reports Server (NTRS)

Radially polarized MAGSAT anomalies of North and South America, Europe, Africa, India, Australia and Antarctica demonstrate remarkably detailed correlation of regional magnetic lithospheric sources across rifted margins when plotted on a reconstruction of Pangea. These major magnetic features apparently preserve their integrity until a superimposed metamorphoric event alters the magnitude and pattern of the anomalies. The longevity of continental scale magnetic anomalies contrasts markedly with that of regional gravity anomalies which tend to reflect predominantly isostatic adjustments associated with neo-tectonism. First observed as a result of NASA's magnetic satellite programs, these anomalies provide new and fundamental constraints on the geologic evolution and dynamics of the continents and oceans. Accordingly, satellite magnetic observations provide a further tool for investigating continental drift to compliment other lines of evidence in paleoclimatology, paleontology, paleomagnetism, and studies of the radiometric ages and geometric fit of the continents.

Vonfrese, R. R. B.; Hinze, W. J.; Olivier, R.; Bentley, C. R.

1985-01-01

21

The source of marine magnetic anomalies  

NASA Technical Reports Server (NTRS)

The Vine-Matthews hypothesis (1963) is examined. This hypothesis suggests that oceanic rocks become polarized in the direction of the magnetic field at the time of their formation, thus recording the polarity history of the earth's magnetic field. This produces the lineated magnetic anomalies on either side of the midoceanic ridge crests. The strength of these magnetic anomalies is studied to determine the strength of magnetization. Indirect determinations of the magnetization intensity of the oceanic crust and direct observations of the oceanic crust are compared. It is found that the average magnetization of a 6-km thick oceanic crust is 1.18 A/m.

Harrison, Christopher G. A.

1987-01-01

22

The magnetic anomaly of the Ivreazone  

NASA Technical Reports Server (NTRS)

A magnetic field survey was made in the Ivreazone in 1969/70. The results were: significant anomaly of the vertical intensity is found. It follows the basic main part of the Ivrea-Verbano zone and continues to the south. The width of the anomaly is about 10 km, the maximum measures about +800 gamma. The model interpretation shows that possibly the anomaly belongs to an amphibolitic body, which in connection with the Ivrea-body was found by deep seismic sounding. Therefore, the magnetic anomaly provides further evidence for the conception that the Ivrea-body has to be regarded as a chip of earthmantle material pushed upward by tectonic processes.

Albert, G.

1979-01-01

23

Reduction of satellite magnetic anomaly data  

NASA Technical Reports Server (NTRS)

Analysis of global magnetic anomaly maps derived from satellite data is facilitated by inversion to the equivalent magnetization in a constant thickness magnetic crust or, equivalently, by reduction to the pole. Previous inversions have proven unstable near the geomagnetic equator. The instability results from magnetic moment distributions which are admissible in the inversion solution but which make only small contribution to the computed values of anomaly field. Their admissibility in the solution could result from noisy or incomplete data or from small poorly resolved anomalies. The resulting magnetic moments are unrealistically large and oscillatory. Application of the method of principal components (e.g. eigenvalue decomposition and selective elimination of less significant eigenvectors) is proposed as a way of overcoming the instability and the method is demonstrated by applying it to the region around the Bangui anomaly in Central Africa.

Slud, E. V.; Smith, P. J.; Langel, R. A.

1984-01-01

24

Understanding Magnetic Anomalies and Their Significance.  

ERIC Educational Resources Information Center

Describes a laboratory exercise testing the Vine-Matthews-Morley hypothesis of plate tectonics. Includes 14 questions with explanations using graphs and charts. Provides a historical account of the current plate tectonic and magnetic anomaly theory. (MVL)

Shea, James H.

1988-01-01

25

Initial scalar magnetic anomaly map from Magsat  

NASA Technical Reports Server (NTRS)

Magsat data acquired during the November 1979-June 1980 mission was used to derive a scalar magnetic anomaly map covering +50 to -50 deg geographic latitude, and the separation of anomaly fields from core and external fields was accomplished by techniques developed for POGO satellite data. Except in the Atlantic and Pacific at latitudes south of -15 deg, comparison of the Magsat map with its POGO data-derived counterpart shows basic anomaly patterns to be reproducible, and higher resolution due to Magsat's lower measurement altitude. Color-coded scalar anomaly maps are presented for both satellites.

Langel, R. A.; Phillips, J. D.; Horner, R. J.

1982-01-01

26

A Magnetic MAP of the Brazilian Anomaly.  

National Technical Information Service (NTIS)

Satellites 'Cosmos 49' and 'Cosmos 26' conducted measurements of the magnetic field by means of the proton magneto-meters according to the program of the world magnetic survey. The area of the Brazilian magnetic anomaly was covered by a dense network of m...

L. V. Konovalova V. I. Nalivaiko

1967-01-01

27

Hematite vs. magnetite as the signature for planetary magnetic anomalies?  

Microsoft Academic Search

Crustal magnetic anomalies are the result of adjacent geologic units having contrasting magnetization. This magnetization arises from induction and\\/or remanence. In a planetary context we now know that Mars has significant crustal magnetic anomalies due to remanent magnetization, while on the Earth both remanence and induction can contribute to the magnetic anomaly, because of the presence of the Earth’s magnetic

Günther Kletetschka; Peter J Wasilewski; Patrick T Taylor

2000-01-01

28

Regional magnetic anomaly constraints on continental breakup  

SciTech Connect

Continental lithosphere magnetic anomalies mapped by the Magsat satellite are related to tectonic features associated with regional compositional variations of the crust and upper mantle and crustal thickness and thermal perturbations. These continental-scale anomaly patterns when corrected for varying observation elevation and the global change in the direction and intensity of the geomagnetic field show remarkable correlation of regional lithospheric magnetic sources across rifted continental margins when plotted on a reconstruction of Pangea. Accordingly, these anomalies provide new and fundamental constraints on the geologic evolution and dynamics of the continents and oceans.

von Frese, R.R.B.; Hinze, W.J.; Olivier, R.; Bentley, C.R.

1986-01-01

29

Satellite elevation magnetic anomaly maps  

NASA Technical Reports Server (NTRS)

The problem of inverting 2 deg average MAGSAT scalar anomalies for the region 80 W, 60 E longitude and 40 S, 70 N latitude was attempted on the LARS computer; however, the effort was aborted due to insufficient allocation of CPU-time. This problem is currently being resubmitted and should be implemented shortly for quantitative comparison with free-air gravity anomaly, geothermal, and tectonic data.

Braile, L. W.; Hinze, W. J. (principal investigators)

1982-01-01

30

The mineralogy of global magnetic anomalies  

NASA Technical Reports Server (NTRS)

Experimental and analytical data on magnetic mineralogy was provided as an aid to the interpretation of magnetic anomaly maps. An integrated program, ranging from the chemistry of materials from 100 or more km depth within the Earth, to an examination of the MAGSAT anomaly maps at about 400 km above the Earth's surface, was undertaken. Within this framework, a detailed picture of the pertinent mineralogical and magnetic relationships for the region of West Africa was provided. Efforts were directed toward: (1) examining the geochemistry, mineralogy, magnetic properties, and phases relations of magnetic oxides and metal alloys in rocks demonstrated to have originated in the lower crust of upper mantle, (2) examining the assumption that these rocks portray the nature of their source regions; and (3) examining the regional geology, tectonics, gravity field and the MAGSAT anomaly maps for West Africa.

Haggerty, S. E. (principal investigator)

1984-01-01

31

Deeptow magnetic survey of the Pacific Jurassic Quiet Zone: Implications for the marine magnetic anomaly timescale  

NASA Astrophysics Data System (ADS)

We present results of a recently completed near-bottom magnetic survey of the Pacific Jurassic quiet zone located in Pigafetta Basin in the vicinity of ODP Hole 801C. A total of ~1550 km of tracklines were completed during 5 lowerings of the DSL120 sidescan sonar system of the National Deep Submergence Facility equipped with two magnetometer systems. The nominal altitude of the vehicle was 100 m above the seafloor with the average sediment thickness ~300 meters. We collected simultaneous vector magnetic data from a digital Honeywell HMR2300 magnetoresistor sensor and absolute total field using a Marine Magnetics Overhauser sensor provided by KORDI. The survey had four primary goals: 1) to investigate the presence or absence of magnetic lineations related to seafloor spreading around ODP Hole 801C, 2) to extend the magnetic anomaly mapping south to the Rough-Smooth (RS) boundary, thought to be the limit of the oldest Pacific crust, 3) to extend and confirm correlations of previously collected deeptow results, and 4) to investigate the M33-M34 sequence which can be clearly correlated with the timescale but also shows a period of rapid field reversal. The survey around Hole 801C was navigated within a transponder net whereas the remainder of the surveys were navigated using acoustic layback and bottom-lock doppler. From our results, we confirm that anomalies in the M33-M34 sequence are highly-lineated and well-correlated between adjacent lines with a high reversal rate. We found that anomalies older than M36 become harder to correlate to about M40 where there may be a possible change in trend of the anomaly strike. The anomaly record appears to become more linear again as Hole 801C is approached. Around Hole 801C the anomalies show a clear lineation with a strike direction of 25 degrees, although the correlation is not as consistent as the younger anomaly sequence. The decrease in anomaly amplitude that is seen from M21 through the M36 sequence appears to be low through anomaly M40 and then increases to a higher value thereafter with an average amplitude of 200 nT at deeptow altitude. South of Hole 801C towards the RS boundary we find that magnetic anomalies continue with short-wavelength anomalies superimposed on a longer wavelength anomalies making them difficult to correlate. High amplitude anomalies mark the RS boundary itself. In summary, we find evidence for seafloor spreading anomalies throughout the survey area although there are areas where correlation is difficult.

Tivey, M. A.; Sager, W. W.; Lee, S.

2003-12-01

32

Satellite Elevation Magnetic Anomaly Maps.  

National Technical Information Service (NTIS)

The problem of inverting 2 deg average MAGSAT scalar anomalies for the region 80 W, 60 E longitude and 40 S, 70 N latitude was attempted on the LARS computer; however, the effort was aborted due to insufficient allocation of CPU-time. This problem is curr...

L. W. Braile W. J. Hinze

1982-01-01

33

The magnetic signature of hydrothermal systems in slow spreading environments  

NASA Astrophysics Data System (ADS)

Slow spreading mid-ocean ridges like the Mid-Atlantic Ridge host a remarkable diversity of hydrothermal systems including vent systems located on the neovolcanic axis, large axial volcanoes, in transform faults and nontransform offsets, and associated with low-angle detachment faults, now recognized as a major tectonic feature of slow spreading environments. Hydrothermal systems are hosted in various lithologies from basalt to serpentinized peridotite and exposed lower oceanic crust. The substantial variations of hydrothermal processes active in these environments have important implications for the magnetic structure of oceanic crust and upper mantle. Hydrothermal processes can both destroy the magnetic minerals in basalt, diabase, and gabbro and create magnetic minerals by serpentinization of ultramafic rocks and deposition of magnetic minerals. We report on the diversity of magnetic anomaly signatures over the vent systems at slow spreading ridges and show that the lateral scale of hydrothermal alteration is fundamentally a local phenomenon. This highly focused process leads to magnetic anomalies on the scale of individual vent fields, typically a few hundreds of meters or less in size. To detect such features, high-resolution, near-bottom magnetic surveys are required rather than sea surface surveys. High-resolution surveys are now more tractable with deep-towed systems, dynamically positioned ships, and with the recent development of autonomous underwater vehicles, which allow detailed mapping of the seafloor on a scale relevant to hydrothermal activity. By understanding these present-day active hydrothermal systems, we can explore for yet to be discovered buried deposits preserved off-axis, both to determine past history of hydrothermal activity and for resource assessment.

Tivey, Maurice A.; Dyment, Jérôme

34

Continental magnetic anomaly constraints on continental reconstruction  

NASA Technical Reports Server (NTRS)

Crustal magnetic anomalies mapped by the MAGSAT satellite for North and South America, Europe, Africa, India, Australia and Antarctica and adjacent marine areas were adjusted to a common elevation of 400 km and differentially reduced to the radial pole of intensity 60,000 nT. These radially polarized anomalies are normalized for differential inclination, declination and intensity effects of the geomagnetic field, so that in principle they directly reflected the geometric and magnetic polarization attributes of sources which include regional petrologic variations of the crust and upper mantle, and crustal thickness and thermal perturbations. Continental anomalies demonstrate remarkably detailed correlation of regional magnetic sources across rifted margins when plotted on a reconstruction of Pangea. Accordingly, they suggest further fundamental constraints on the geologic evolution of the continents and their reconstructions.

Vonfrese, R. R. B.; Hinze, W. J.; Olivier, R.; Bentley, C. R.

1985-01-01

35

Correction of Marine Magnetic Data to Make a Magnetic Anomaly Map for Shatsky Rise  

NASA Astrophysics Data System (ADS)

Shatsky Rise oceanic plateau was formed near a triple junction during a period of geomagnetic reversals, so magnetic lineations formed at the spreading ridges are important observations reflecting on its tectonic history. Shatsky Rise covers a large area (4.8 x 105 km2) and magnetic data in the area are sparse and irregularly spaced, posing a challenge for defining the magnetic anomalies. Original trackline data contain both natural and artificial artifacts that hinder their effective use. In this study, shipborne magnetic data from 101 cruises over and around Shatsky Rise were examined for errors, corrected and gridded. The data set was collected over a period of 51 years, during which the International Geomagnetic Reference Field (IGRF) changed many times. So the first and main correction was to reduce the total magnetic field data to anomalies by subtracting the most recent International Geomagnetic Reference Field (IGRF11). To correct for regular patterns of external field variations, the anomalies were recalculated by the use of Comprehensive Model: phase 4 (CM4). Observation outliers, usually caused by instrumental and transcription errors, are identifiable due to their extremely large differences from the nearby points. Most of these outliers are excluded and for only a few was it possible to recover reasonable anomaly values. Noisy segments were identified and deleted through inspection by their disagreement with the draft magnetic anomaly map. Position offsets were tested to find corrections for navigation errors for several cruises with poor navigation. After cleaning each cruise data track-by-track, or even segment-by-segment, crossover analysis was implemented and line-leveling is used to correct for systematic offsets between track lines. Comparisons of magnetic anomaly maps before and after these corrections show an apparent improvement of the quality and consistency of the data set. The Hawaiian magnetic lineations, Japanese magnetic lineations, and the trace of the Pacific-Izanagi-Farallon triple junction are identifiable in the magnetic anomaly map. The distribution of magnetic anomalies around and within Shatsky rise shows that magnetic anomalies penetrate most of Shatsky Rise, documenting its history of formation near the spreading ridges.

Huang, Y.; Sager, W. W.

2013-12-01

36

CHAMP Magnetic Anomalies of the Antarctic Crust  

NASA Technical Reports Server (NTRS)

Regional magnetic signals of the crust are strongly masked by the core field and its secular variations components and hence difficult to isolate in the satellite measurements. In particular, the un-modeled effects of the strong auroral external fields and the complicated- behavior of the core field near the geomagnetic poles conspire to greatly reduce the crustal magnetic signal-to-noise ratio in the polar regions relative to the rest of the Earth. We can, however, use spectral correlation theory to filter the static lithospheric and core field components from the dynamic external field effects. To help isolate regional lithospheric from core field components, the correlations between CHAMP magnetic anomalies and the pseudo magnetic effects inferred from gravity-derived crustal thickness variations can also be exploited.. Employing these procedures, we processed the CHAMP magnetic observations for an improved magnetic anomaly map of the Antarctic crust. Relative to the much higher altitude Orsted and noisier Magsat observations, the CHAMP magnetic anomalies at 400 km altitude reveal new details on the effects of intracrustal magnetic features and crustal thickness variations of the Antarctic.

Kim, Hyung Rae; Gaya-Pique, Luis R.; vonFrese, Ralph R. B.; Taylor, Patrick T.; Kim, Jeong Woo

2003-01-01

37

Plasma structure over dayside lunar magnetic anomalies  

NASA Astrophysics Data System (ADS)

It is well-known that the Moon has neither global intrinsic magnetic field nor thick atmosphere. Different from the Earth’s case where the intrinsic global magnetic field prevents the solar wind from penetrating into the magnetosphere, solar wind directly impacts the lunar surface. Since the discovery of the lunar crustal magnetic field in 1960s, several papers have been published concerning the interaction between the solar wind and the lunar magnetic anomalies including both numerical simulations and observation by lunar orbiters. MAG/ER on Lunar Prospector found heating of the solar wind electrons presumably due to the interaction between the solar wind and the lunar magnetic anomalies and the existence of the mini-magnetosphere was suggested. However, the detailed mechanism of the interaction has been unclear mainly due to the lack of the in-situ observed low energy ion data. MAgnetic field and Plasma experiment - Plasma energy Angle and Composition Experiment (MAP-PACE) on Kaguya (SELENE) completed its ˜1.5-year observation of the low energy charged particles around the Moon on 10 June 2009. MAP-PACE made observations at a circular lunar polar orbit of 100km altitude for about 1 year between January 2008 and December 2008. During the last 5 months, the orbit was lowered to ˜50km-altitude between January 2009 and April 2009, and some orbits had further lower perilune altitude of ˜10km after April 2009. When Kaguya flew over strong magnetic anomalies, deceleration of the solar wind ions, acceleration of the solar wind electrons, and ions reflected by magnetic anomalies were observed. The deceleration of the solar wind ions was observed for both two major solar wind ion components: protons and alpha particles. Deceleration of the solar wind had the same ? E/q (? E : deceleration energy, q: charge) for both protons and alpha particles. In addition, the acceleration energy of the electrons was the same as the deceleration energy of the ions. It indicates the existence of DC electric field over Kaguya spacecraft. Since the gyro-radius of the electrons was smaller than the size of the magnetic anomalies, incident electrons were mirror reflected back. On the other hand, the gyro-radius of the ions was much larger than the size of the magnetic anomalies. Therefore the incident ions could penetrate deeper into the magnetic anomalies. As a result, DC electric field was generated over dayside magnetic anomalies. The reflected ions were observed in much larger area than the area where strong magnetic field was observed. Mass profile of the reflected ions showed existence of reflected alpha particles as expected from the magnetic mirror reflection. However, the energy of the reflected alpha particles was found to be lower than that of the alpha particles in the incident solar wind. In addition, the reflected protons also had lower energy and higher temperature than those of the incident solar wind protons. It clearly indicates the existence of a non-adiabatic interaction between solar wind ions and lunar magnetic anomalies.

Saito, Y.; Nishino, M. N.; Yamamoto, T.; Uemura, K.; Yokota, S.; Asamura, K.; Tsunakawa, H.; Kaguya Map Team

2010-12-01

38

Paleo-Pole Positions from Martian Magnetic Anomaly Data.  

National Technical Information Service (NTIS)

Magnetic component anomaly maps were made from five mapping cycles of the Mars Global Surveyor's magnetometer data. Our goal was to find and isolate positive and negative anomaly pairs which would indicate magnetization of a single source body. From these...

J. J. Frawley P. T. Taylor

2004-01-01

39

Mapping a bubble at dip equator and anomaly with oblique ionospheric soundings of range spread F  

SciTech Connect

Multiple ionospheric sounders are employed in the first attempt to detect and map remotely an equatorial bubble near the dip equator and simultaneously near the Appleton anomaly crest. The sounders also provide latitudinal profiles of electron density through {+-} 30{degrees} dip latitude (DIPLAT). Conditions are solar maximum and low Kp. Using oblique range spread F (RSF) echoes from the bubble boundaries, four sounders located near the dip equator detect a single isolated bubble at ranges as great as a 1020 km and track it for 2.25 hours at 5-min intervals as it drifts eastward through 15{degrees} geomagnetic longitude (MLONG). Maximum velocity is 185 m/s, and width is 375 km. Near the northern anomaly crest, a sounder at 20.3{degrees} DIPLAT observes the western boundary for a duration of 1 hour concurrently with and magnetically conjugate to the equatorial observations. The boundary here has nearly the same drift velocity and MLONG as at the equator, implying that the boundary location and velocity are nearly independent of altitude above the dip equator. Subsequently, in the south a sounder at 19.9{degrees} DIPLAT observes the bubble to have a velocity approximately half that seen by other stations and a MLONG that is at least 3{degrees} west of the others. This difference may be related to the north-south asymmetry of the anomaly crest, which is at the location of the northern sounder but equatorward of the southern sounder, although the two are at the same DIPLAT. The onset of the bubble is recorded in the first appearance of RSF at 1915 local mean time; 20 min later the bubble boundary appears and begins accelerating eastward, the movement occurring within about 5 min of electric field reversal as inferred from F layer vertical motion. 30 refs., 8 figs.

Whalen, J.A. [Phillips Laboratory, Hanscom Air Force Base, MA (United States)] [Phillips Laboratory, Hanscom Air Force Base, MA (United States)

1996-03-01

40

Explanation of the nature of stripe magnetic anomalies without inversions  

NASA Astrophysics Data System (ADS)

Several scientists of different branches express doubts on the validity of the Earth's geomagnetic field inversions hypothesis [Vine F.J., Matthews D.H, 1963]. Presently a lot of information allows to link the appearance of stripe magnetic anomalies of both signs with the spreading fracture structure (horizontal segmentation of intrusions and sills, breaks in the strong crust, vertical movements of blocks), remagnetization near the borders of the blocks, hydrothermal activity. Non-inversion mechanism of origin of linear stripe magnetic anomalies in the oceans could be explained as follows. Ascending asthenospheric flows have been enrich with volatile components, become thinner, pressure on the walls of the lithospheric plates grows and part them. When it approaches the surface: - horizontal tensile pressure grows, - lithostatic pressure in the vertical column of rocks decreases, - crust strong upper layer flakes away and begins to move horizontally. It is important that thin magmatic and magnetic layers (further layers) of the newly formed strong upper crust move away from the ridge axis. The structure of such layers forms by horizontal stresses and so consist of the hills and depressions sequences or updiped and downdiped blocks heaped each other. This layer is the main source of the magnetic field and cannot be approximated by a horizontal homogeneous plate as it proved before. In the mid-ocean ridges (MOR) the folding periods of layer depend on its thickness and rigidity and horizontal velocity of spreading. The higher velocity - the longer periods of roughness are and contrary. Same pattern is observed for the stripe magnetic anomalies distribution. The magnetic field of the MOR forms there due to young lava flows which get thermoremanent magnetization according the current direction of geomagnetic field. Partial destruction of the relief, overlaying and creation of the new shapes occur when new magma penetrates the moved magnetic layer. The process entails partial flux reversal of rocks with the decrease of total magnetic field amplitude. The complicated magnetic field with alternating-sign linear anomalies appears. Taking into account limited vertical thickness of the oceanic magnetic layer, the false effect of negative magnetization would appear even with short shifts of the blocks. Conclusions. Theoretical calculations and analysis 'in situ' data prove that observation of magnetic anomalies of both signs in MOR areas are connected with fracturing tectonics, horizontal segmentation of sills, faults in the crust, vertical movements of blocks, self remagnetization near its margins. At the present time geological and geophysical facts lead to revision of some facts of tectonic theory and rejection of the old hypothesis connected with simplified ideas of the magnetic layer regularity and cyclical nature of magma flows. The main task of this work is to return scientists to the initial point of stripe magnetic anomalies discovery and general revision of the oceanic crust's structure without the limitations of Vine-Matthews-Morley hypothesis. Please fill in your abstract text.

Melikhov, Vjacheslav; Lygin, Ivan; Sokolova, Tatiana

2014-05-01

41

Initial vector magnetic anomaly map from Magsat  

NASA Technical Reports Server (NTRS)

Global magnetic component anomaly field maps have been derived from the Magsat vector magnetometer data obtained from November 1979 through May 1980. The amplitude of variations of the components over the maps are between 10 and 15 nT, well above the noise in the data. Averaged data, in 2-by-2 deg blocks, exhibit standard errors of the mean of about 1 nT over most of the X and Z maps, and about 2 nT over most of the Y maps. Errors rise to about twice these amounts near the auroral belts. Most of the anomalies in the component data are consistent with a crustal magnetization model which incorporates dipoles aligned only in the direction of the main field. However, there appear to be some regions which require dipoles aligned in some other direction i.e., remanent magnetization.

Langel, R. A.; Schnetzler, C. C.; Phillips, J. D.; Horner, R. J.

1982-01-01

42

Equivalent magnetization over the World's Ocean and the World Digital Magnetic Anomaly Map  

NASA Astrophysics Data System (ADS)

As a by-product of our recent work to build a candidate model over the oceans for the second version of the World Digital Magnetic Anomaly Map (WDMAM), we derived global distributions of the equivalent magnetization in oceanic domains. In a first step, we use classic point source forward modeling on a spherical Earth to build a forward model of the marine magnetic anomalies at sea-surface. We estimate magnetization vectors using the age map of the ocean floor, the relative plate motions, the apparent polar wander path for Africa, and a geomagnetic reversal time scale. We assume two possible magnetized source geometry, involving both a 1 km-thick layer bearing a 10 A/m magnetization either on a regular spherical shell with a constant, 5 km-deep, bathymetry (simple geometry) or following the topography of the oceanic basement as defined by the bathymetry and sedimentary thickness (realistic geometry). Adding a present-day geomagnetic field model allows the computation of our initial magnetic anomaly model. In a second step, we adjust this model to the existing marine magnetic anomaly data, in order to make it consistent with these data. To do so, we extract synthetic magnetic along the ship tracks for which real data are available and we compare quantitatively the measured and computed anomalies on 100, 200 or 400 km-long sliding windows (depending the spreading rate). Among the possible comparison criteria, we discard the maximal range - too dependent on local values - and the correlation and coherency - the geographical adjustment between model and data being not accurate enough - to favor the standard deviation around the mean value. The ratio between the standard deviations of data and model on each sliding window represent an estimate of the magnetization ratio causing the anomalies, which we interpolate to adjust the initial magnetic anomaly model to the data and therefore compute a final model to be included in our WDMAM candidate over the oceanic regions lacking data. The above ratio, after division by the magnetization of 10 A/m used in the model, represents an estimate of the equivalent magnetization under the considered magnetized source geometry. The resulting distributions of equivalent magnetization are further discussed in terms of mid-ocean ridges, presence of hotspots and oceanic plateaus, and the age of the oceanic lithosphere. Global marine magnetic data sets and models represent a useful tool to assess first order magnetic properties of the oceanic lithosphere.

Dyment, Jerome; Choi, Yujin; Hamoudi, Mohamed; Thébault, Erwan; Quesnel, Yoann; Roest, Walter; Lesur, Vincent

2014-05-01

43

A strong magnetic anomaly affects pigeon navigation.  

PubMed

Pigeons were released in a strong magnetic anomaly with fast changes in intensity and gradients directions, about 60 km from their loft, and, for comparison, at the border of the anomaly and at a control site. The vanishing bearings were found to be closely related to the home direction, but unrelated to the local gradient directions. The vector lengths and the vanishing intervals, however, were significantly correlated with the maximum difference in intensity within a 2.5 km radius around the release site. This correlation was negative for the vector lengths and positive for the vanishing intervals, indicating that steep local gradients increase scatter between pigeons and delay their departure. These findings suggest that an irregular, fast changing magnetic field as found in the anomaly leads to confusion during the navigational processes. This, in turn, implies that pigeons can sense the respective changes in magnetic intensity. Magnetic cues seem to be included in the normal navigational processes that determine the departure direction. PMID:19717681

Wiltschko, Roswitha; Schiffner, Ingo; Wiltschko, Wolfgang

2009-09-15

44

Magnetic anomalies northeast of Cape Adare, northern Victoria Land (Antarctica), and their relation to onshore structures  

USGS Publications Warehouse

An aeromagnetic survey was flown over the offshore region northeast of Cape Adare and the magnetic anomalies compared to onshore structures between Pennell Coast and Tucker Glacier. The magnetic anomalies show two nearly orthogonal major trends. NNW-SSE trending anomalies northeast of Cape Adare represent seafloor spreading within the Adare Trough. A connection of these anomalies to the Northern Basin of the Ross Sea is not clear. Onshore faults are closely aligned to offshore anomalies. Main trends are NW-SE to NNW-SSE and NE-SW to NNESSW. NNW-SSE oriented dextral-transtensional to extensional faults parallel the Adare Peninsula and Adare Trough anomalies. NE-SW trending normal faults appear to segment the main Hallett volcanic bodies.

Damaske, D.; Läufer, A.L.; Goldmann, F.; Möller, H.-D.; Lisker, F.

2007-01-01

45

Spreading of Psoriatic Plaques: Alteration of Epidermal Differentiation Precedes Capillary Leakiness and Anomalies in Vascular Morphology  

Microsoft Academic Search

To approach the temporal relationship between alterations in keratinization and capillary leakiness in psoriasis, we studied the topography of these anomalies in spreading psoriatic lesions- Histological and immunohistochemical studies were performed on skin biopsies obtained from normal individuals and from psoriatic patients. In the latter case, biopsies were taken in uninvolved skin, in the center of lesions, and at the

Dominique Parent; Bruno A. Bernard; Christiane Desbas; Michel Heenen; Michel Y. Darmon

1990-01-01

46

Paleo-Pole Positions from Martian Magnetic Anomaly Data  

NASA Technical Reports Server (NTRS)

Magnetic component anomaly maps were made from five mapping cycles of the Mars Global Surveyor's magnetometer data. Our goal was to find and isolate positive and negative anomaly pairs which would indicate magnetization of a single source body. From these anomalies we could compute the direction of the magnetizing vector and subsequently the location of the magnetic pole existing at the time of magnetization. We found nine suitable anomaly pairs and from these we computed paleo-poles that were nearly equally divided between north, south and mid-latitudes. These results suggest that during the existence of the martian main magnetic field it experienced several reversals and excursions.

Frawley, James J.; Taylor, Patrick T.

2004-01-01

47

Paleo-Pole Positions from Martian Magnetic Anomaly Data  

NASA Technical Reports Server (NTRS)

Magnetic component anomaly maps were made from five mapping cycles of the Mars Global Surveyor s magnetometer data. Our goal was to find and isolate positive and negative anomaly pairs which would indicate magnetization of a single source body. From these anomalies we could compute the direction of the magnetizing vector and subsequently the location of the magnetic pole existing at the time of magnetization. We found nine suitable anomaly pairs and from these we computed four North and 3 South poles with two at approximately 60 degrees north latitude. These results suggest that during the existence of the Martian main magnetic field it experienced several reversals.

Taylor, Patrick T.; Frawley, James J.

2003-01-01

48

Crustal Magnetic Field Anomalies and Global Tectonics  

NASA Astrophysics Data System (ADS)

A wide variety of evidence suggests that the ruling isochron (geomagnetic polarity versus age) hypothesis of marine magnetic lineations has no merit - undermining therefore one of the central tenets of plate tectonics. Instead, variable induction by the ambient geomagnetic field is likely to be the principal agent for mega-scale crustal magnetic features - in both oceanic and continental settings. This revitalizes the fault-controlled susceptibility-contrast model of marine magnetic lineations, originally proposed in the late 1960s. Thus, the marine magnetic 'striping' may be ascribed to tectonic shearing and related, but variable, disintegration of the original iron-oxide mineralogy, having developed primarily along one of the two pan-global sets of orthogonal fractures and faults. In this way, fault zones (having the more advanced mineral alteration) would be characterized by relatively low susceptibility, while more moderately affected crustal sections (located between principal fault zones) would be likely to have less altered oxide mineralogy and therefore higher magnetic susceptibility. On this basis, induction by the present geomagnetic field is likely to produce oscillating magnetic field anomalies with axis along the principal shear grain. The modus operandi of the alternative magneto-tectonic interpretation is inertia-driven wrenching of the global Alpine age palaeo-lithosphere - triggered by changes in Earth's rotation. Increasing sub-crustal loss to the upper mantle during the Upper Mesozoic had left the ensuing Alpine Earth in a tectonically unstable state. Thus, sub-crustal eclogitization and associated gravity-driven delamination to the upper mantle led to a certain degree of planetary acceleration which in turn gave rise to latitude-dependent, westward inertial wrenching of the global palaeo-lithosphere. During this process, 1) the thin and mechanically fragile oceanic crust were deformed into a new type of broad fold belts, and 2) the continents were subjected to relative 'in situ' rotations (mostly moderate). Examples of marine magnetic lineations with landward continuation along prominent transcurrent fault zones, and the fact that striped marine magnetic anomalies may display orthogonal networks - concordant with the ubiquitous system of rectilinear fractures, faults and joints - corroborate the wrench tectonic interpretation of crustal field anomalies.

Storetvedt, Karsten

2014-05-01

49

Modelling and inversion of local magnetic anomalies  

NASA Astrophysics Data System (ADS)

We present a method—named as MILMA for modelling and inversion of local magnetic anomalies—that combines forward and inverse modelling of aeromagnetic data to characterize both magnetization properties and location of unconstrained local sources. Parameters of simple-shape magnetized bodies (cylinder, prism or sphere) are first adjusted by trial and error to predict the signal. Their parameters provide a priori information for inversion of the measurements. Here, a generalized nonlinear approach with a least-squares criterion is adopted to seek the best parameters of the sphere (dipole). This inversion step allows the model to be more objectively adjusted to fit the magnetic signal. The validity of the MILMA method is demonstrated through synthetic and real cases using aeromagnetic measurements. Tests with synthetic data reveal accurate results in terms of depth source, whatever be the number of sources. The MILMA method is then used with real measurements to constrain the properties of the magnetized units of the Champtoceaux complex (France). The resulting parameters correlate with the crustal structure and properties revealed by other geological and geophysical surveys in the same area. The MILMA method can therefore be used to investigate the properties of poorly constrained lithospheric magnetized sources.

Quesnel, Y.; Langlais, B.; Sotin, C.; Galdéano, A.

2008-12-01

50

A global magnetic anomaly map. [obtained from POGO satellite data  

NASA Technical Reports Server (NTRS)

A subset of POGO satellite magnetometer data has been formed that is suitable for analysis of crustal magnetic anomalies. Using a thirteenth order field model, fit to these data, magnetic residuals have been calculated over the world to latitude limits of plus 50 deg. These residuals averaged over one degree latitude-longitude blocks represent a detailed global magnetic anomaly map derived solely from satellite data. Preliminary analysis of the map indicates that the anomalies are real and of geological origin.

Regan, R. D.; Davis, W. M.; Cain, J. C.

1974-01-01

51

The Inversion of Magnetic Anomalies in the Presence of Topography  

Microsoft Academic Search

The inversion of magnetic anomalies in terms of an irregular layer of magnetized material is studied, and an efficient procedure for constructing solutions is developed. Even when magnetic orientation and layer thickness are known, the solution is not unique because of the existence of a magnetization (called the magnetic annihilator) that produces no observable magnetic field. We consider an example

R. L. Parker; S. P. Huestis

1974-01-01

52

Resolving the heat-flow anomaly at the Galapagos Spreading Center  

Microsoft Academic Search

Two dimensional, finite-difference, porous medium models were developed for hydrothermal circulation at the Galapagos Spreading Center. The models span the entire region of the Galapagos heat-flow anomaly and by means of an assumed heat-transfer coefficient allow for convective, as well as conductive, heat transfer from the crust to the overlying ocean. The models incorporate the theoretically predicted heat-flow distribution into

P. L. Patterson

1980-01-01

53

Remote energetic neutral atom imaging of electric potential over a lunar magnetic anomaly  

NASA Astrophysics Data System (ADS)

Abstract<p label="1">The formation of electric potential over lunar <span class="hlt">magnetized</span> regions is essential for understanding fundamental lunar science, for understanding the lunar environment, and for planning human exploration on the Moon. A large positive electric potential was predicted and detected from single point measurements. Here, we demonstrate a remote imaging technique of electric potential mapping at the lunar surface, making use of a new concept involving hydrogen neutral atoms derived from solar wind. We apply the technique to a lunar <span class="hlt">magnetized</span> region using an existing dataset of the neutral atom energy spectrometer SARA/CENA on Chandrayaan-1. Electrostatic potential larger than +135 V inside the Gerasimovic <span class="hlt">anomaly</span> is confirmed. This structure is found <span class="hlt">spreading</span> all over the <span class="hlt">magnetized</span> region. The widely <span class="hlt">spread</span> electric potential can influence the local plasma and dust environment near the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>.</p> <div class="credits"> <p class="dwt_author">Futaana, Y.; Barabash, S.; Wieser, M.; Lue, C.; Wurz, P.; Vorburger, A.; Bhardwaj, A.; Asamura, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">54</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22255538"> <span id="translatedtitle">Indoor waypoint navigation via <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">A wide assortment of technologies have been proposed to construct indoor navigation services for the blind and vision impaired. Proximity-based systems and multilateration systems have been successfully demonstrated and employed. Despite the technical success of these technologies, broad adoption has been limited due to their significant infrastructure and maintenance costs. An alternative approach utilizing the indoor <span class="hlt">magnetic</span> signatures inherent to steel-frame buildings solves the infrastructure cost problem; in effect the existing building is the location system infrastructure. Although <span class="hlt">magnetic</span> indoor navigation does not require the installation of dedicated hardware, the dedication of resources to produce precise survey maps of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> represents a further barrier to adoption. In the present work an alternative leader-follower form of waypoint-navigation system has been developed that works without surveyed <span class="hlt">magnetic</span> maps of a site. Instead the wayfarer's magnetometer readings are compared to a pre-recorded <span class="hlt">magnetic</span> "leader" trace containing <span class="hlt">magnetic</span> data collected along a route and annotated with waypoint information. The goal of the navigation system is to correlate the follower's magnetometer data with the leader's to trigger audio cues at precise points along the route, thus providing location-based guidance to the user. The system should also provide early indications of off-route conditions. As part of the research effort a smartphone based application was created to record and annotate leader traces with audio and numeric data at waypoints of interest, and algorithms were developed to determine (1) when the follower reaches a waypoint and (2) when the follower goes off-route. A navigation system utilizing this technology would enable a low-cost indoor navigation system capable of replaying audio annotations at precise locations along pre-recorded routes. PMID:22255538</p> <div class="credits"> <p class="dwt_author">Riehle, Timothy H; Anderson, Shane M; Lichter, Patrick A; Condon, John P; Sheikh, Suneel I; Hedin, Daniel S</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">55</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20000080805&hterms=strong&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dstrong"> <span id="translatedtitle">Strong <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> on the Lunar Near Side</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The near side <span class="hlt">magnetic</span> field is dominated by the demagnetized Imbrium basin and Oceanus Procellarum regions. However, surrounding this area are a number of strong <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, including Rima Sirsalis and Reiner Gamma.</p> <div class="credits"> <p class="dwt_author">Halekas, J. S.; Mitchell, D. L.; Lin, R. P.; Frey, S.; Acuna, M. H.; Hood, L. L.; Binder, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">56</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850023272&hterms=PangeA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DPangeA"> <span id="translatedtitle">Improving the geological interpretation of <span class="hlt">magnetic</span> and gravity satellite <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Current limitations in the quantitative interpretation of satellite-elevation geopotential field data and <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data were investigated along with techniques to overcome them. A major result was the preparation of an improved scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map of South America and adjacent marine areas directly from the original MAGSAT data. In addition, comparisons of South American and Euro-African data show a strong correlation of <span class="hlt">anomalies</span> along the Atlantic rifted margins of the continents.</p> <div class="credits"> <p class="dwt_author">Hinze, W. J.; Braile, L. W. (principal investigators); Vonfrese, R. R. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">57</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUSMGP41A..12N"> <span id="translatedtitle">A <span class="hlt">Magnetic</span> Petrology Database for Satellite <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Interpretations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A <span class="hlt">Magnetic</span> Petrology Database (MPDB) is now being compiled at NASA/Goddard Space Flight Center in cooperation with Russian and Ukrainian Institutions. The purpose of this database is to provide the geomagnetic community with a comprehensive and user-friendly method of accessing <span class="hlt">magnetic</span> petrology data via Internet for more realistic interpretation of satellite <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. <span class="hlt">Magnetic</span> Petrology Data had been accumulated in NASA/Goddard Space Flight Center, United Institute of Physics of the Earth (Russia) and Institute of Geophysics (Ukraine) over several decades and now consists of many thousands of records of data in our archives. The MPDB was, and continues to be in big demand especially since recent launching in near Earth orbit of the mini-constellation of three satellites - Oersted (in 1999), Champ (in 2000), and SAC-C (in 2000) which will provide lithospheric <span class="hlt">magnetic</span> maps with better spatial and amplitude resolution (about 1 nT). The MPDB is focused on lower crustal and upper mantle rocks and will include data on mantle xenoliths, serpentinized ultramafic rocks, granulites, iron quartzites and rocks from Archean-Proterozoic metamorphic sequences from all around the world. A substantial amount of data is coming from the area of unique Kursk <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> and Kola Deep Borehole (which recovered 12 km of continental crust). A prototype MPDB can be found on the Geodynamics Branch web server of Goddard Space Flight Center at http://core2.gsfc.nasa.gov/terr_mag/magnpetr.html. The MPDB employs a searchable relational design and consists of 7 interrelated tables. The schema of database is shown at http://core2.gsfc.nasa.gov/terr_mag/doc.html. MySQL database server was utilized to implement MPDB. The SQL (Structured Query Language) is used to query the database. To present the results of queries on WEB and for WEB programming we utilized PHP scripting language and CGI scripts. The prototype MPDB is designed to search database by major satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, tectonic structure, geographical location, rock type, <span class="hlt">magnetic</span> properties, chemistry and reference, see http://core2.gsfc.nasa.gov/terr_mag/query1.html. The output of database is HTML structured table, text file, and downloadable file. This database will be very useful for studies of lithospheric satellite <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> on the Earth and other terrestrial planets.</p> <div class="credits"> <p class="dwt_author">Nazarova, K.; Wasilewski, P.; Didenko, A.; Genshaft, Y.; Pashkevich, I.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">58</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/46625576"> <span id="translatedtitle">A computer program to estimate the source body <span class="hlt">magnetization</span> direction from <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper, a FORTRAN 77 computer program that estimates the inclination and declination of the <span class="hlt">magnetization</span> of a body causing a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is presented. The program searches for maximum correlation in between the pseudogravity <span class="hlt">anomalies</span> at ranges of body <span class="hlt">magnetization</span> and gravity <span class="hlt">anomalies</span> caused by the same formations. The pseudogravity transformation is performed each time for an array</p> <div class="credits"> <p class="dwt_author">F. Bilim; A Ates</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">59</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUSMGP41A..02K"> <span id="translatedtitle">Antarctic lithospheric <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from ADMAP, CHAMP and Ørsted data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Lithospheric <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over the Antarctic were extracted from recent Ørsted and CHAMP satellite scalar magnetometer data and merged with ship and airborne <span class="hlt">magnetic</span> surveys compiled by the Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP). Using the pseudo <span class="hlt">magnetic</span> effects of the crustal thickness variations, we resolved the core field and external field components in the satellite <span class="hlt">magnetic</span> observations. The intra-crustal components of the lithospheric <span class="hlt">anomalies</span> were then computed at 400 km and 700 km altitude from the CHAMP and Ørsted survey data, respectively. Inversion from using the estimates for a spherical prism model of crustal <span class="hlt">magnetization</span> was used to fill the regional gaps in the ship and airborne surveys. The gap predictions were then validated against the observations around the gap boundaries. The model filled the gaps in the ship and airborne surveys and satisfied the multi-altitude satellite <span class="hlt">anomalies</span>. A spherical cap harmonic model is developed to represent the multi-altitude lithospheric <span class="hlt">anomaly</span> components in ADMAP. <span class="hlt">Magnetic</span> <span class="hlt">anomaly</span> gradients from the SWARM mission will further enhance our estimation of the <span class="hlt">anomalies</span> in the near-surface <span class="hlt">magnetic</span> data of this continent.</p> <div class="credits"> <p class="dwt_author">Kim, H.; Taylor, P. T.; von Frese, R. R.; Golynsky, A. V.; Gaya-Pique, L. R.; Kim, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">60</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.agu.org/journals/jb/v075/i005/JB075i005p00903/JB075i005p00903.pdf"> <span id="translatedtitle"><span class="hlt">Magnetic</span> and Bathymetrie Data Bearing on Sea-Floor <span class="hlt">Spreading</span> North of Iceland</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">rates of 1.0 cm\\/yr normal to the ridge crests between Iceland and the Jan Mayen fracture zone and on Mohns ridge. The trans-Arctic extension of the ridge is characterized by anomalously great water depths and <span class="hlt">spreading</span> rates probably I cm\\/yr or less. The <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> signatures reveal exceptionally low amplitudes compared to other ridges, even when these factors are taken</p> <div class="credits"> <p class="dwt_author">Peter R. Vogt; Ned A. Ostenso; G. Leonard Johnson</p> <p class="dwt_publisher"></p> <p class="publishDate">1970-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_2");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a style="font-weight: bold;">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a 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src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_3");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a style="font-weight: bold;">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_5");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">61</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850003130&hterms=bouguer+anomaly+gravity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dbouguer%2Banomaly%2Bgravity"> <span id="translatedtitle">The south-central United States <span class="hlt">magnetic</span> <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The South-Central United States <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> is the most prominent positive feature in the MAGSAT scalar <span class="hlt">magnetic</span> field over North America. The <span class="hlt">anomaly</span> correlates with increased crustal thickness, above average crustal velocity, negative free air gravity <span class="hlt">anomalies</span> and an extensive zone of Middle Proterozoic anorogenic felsic basement rocks. Spherical dipole source inversion of the MAGSAT scalar data and subsequent calculation of reduced to pole and derivative maps provide constraints for a crustal <span class="hlt">magnetic</span> model which corresponds geographically to the extensive Middle Proterozoic felsic rocks trending northeasterly across the United States. These felsic rocks contain insufficient <span class="hlt">magnetization</span> or volume to produce the <span class="hlt">anomaly</span>, but are rather indicative of a crustal zone which was disturbed during a Middle Proterozoic thermal event which enriched <span class="hlt">magnetic</span> material deep in the crust.</p> <div class="credits"> <p class="dwt_author">Hinze, W. J.; Braile, L. W. (principal investigators); Starich, P. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">62</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820014754&hterms=CURIE+POINT&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCURIE%2BPOINT"> <span id="translatedtitle">Study of gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> using MAGSAT data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The results of modeling satellite-elevation <span class="hlt">magnetic</span> and gravity data using the constraints imposed by near surface data and seismic evidence shows that the <span class="hlt">magnetic</span> minimum can be accounted for by either an intracrustal lithologic variation or by an upwarp of the Curie point isotherm. The long wavelength <span class="hlt">anomalies</span> of the NOO's-vector <span class="hlt">magnetic</span> survey of the conterminous U.S. were contoured and processed by various frequency filters to enhance particular characteristics. A preliminary inversion of the data was completed and the <span class="hlt">anomaly</span> field calculated at 450 km from the equivalent <span class="hlt">magnet</span> sources to compare with the POGO satellite data. Considerable progress was made in studing the satellite <span class="hlt">magnetic</span> data of South America and adjacent marine areas. Preliminary versions of the 1 deg free-air gravity <span class="hlt">anomaly</span> map (20 m gal contour interval) and the high cut (lambda approximately 8 deg) filtered <span class="hlt">anomaly</span> maps are included.</p> <div class="credits"> <p class="dwt_author">Braile, L. W.; Hinze, W. J.; Vonfrese, R. R. B. (principal investigators)</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">63</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFMGP21A0772G"> <span id="translatedtitle">Using fracture zones <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> to unravel the long-term behavior of the geomagnetic field</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Marine <span class="hlt">magnetic</span> profiles oriented along the <span class="hlt">spreading</span> direction have been used to study paleointensity variations of the geomagnetic field. These data-sets have confirmed the link between crustal <span class="hlt">magnetization</span> and past geomagnetic field variations. An additional set of globally distributed <span class="hlt">anomalies</span>, oriented perpendicular to the <span class="hlt">spreading</span> flow-line direction, are located above oceanic fracture zones. These <span class="hlt">anomalies</span> have never been used to study the geomagnetic field nor has their origin been systematically studied. Here we present the first attempt to use these <span class="hlt">anomalies</span> to study the long-term behavior of the geomagnetic field in the Cretaceous normal polarity superchron. We use archival data and new <span class="hlt">magnetic</span> and bathymetry data acquired on geophysical cruise MGLN44MV aboard the R/V Melville on the Pioneer and the Murray fracture zones, North Pacific. These Fracture zones straddle the fast-<span class="hlt">spreading</span> Pacific Cretaceous Quiet Zone (KQZ) and provide a relatively simple setting to test the feasibility of our approach. We use data from 150 crossings that cover a time-span of 27 million years (110 to 83 Ma). The <span class="hlt">anomalies</span> demonstrate a remarkable uniform shape and size for thousands of kilometers implying that they were generated by spatially and temporally uniform processes. Two dimensional inversion solutions together with 3D forward models suggest that remanent <span class="hlt">magnetization</span> governs the <span class="hlt">magnetic</span> signal. These models also imply that enhanced <span class="hlt">magnetization</span>, primarily situated within the uplifted regions adjacent to fracture zones, is responsible for the observed <span class="hlt">anomalies</span>. The actual mechanism that creates these <span class="hlt">magnetization</span> highs is not known, yet the inference of remanent <span class="hlt">magnetization</span> allows us to use the <span class="hlt">anomalies</span> to explore the behavior of the geomagnetic field. The nearly uniform amplitude of the <span class="hlt">anomalies</span> suggests that the strength of the geomagnetic field remained relatively constant over most of the superchron. If a change in the geodynamo behavior is linked with changes in frequency of reversals then this change should have taken place after (and probably before) the superchron. Initial analysis of crossings located on crust younger then the KQZ suggests that in-fact, the Cenozoic field had similar strength as the superchron.</p> <div class="credits"> <p class="dwt_author">Granot, R.; Cande, S.; Gee, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">64</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54429066"> <span id="translatedtitle">Cascadia Gravity and <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Delineate Hydrated Forearc Mantle</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Very high-amplitude <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> along the eastern margin of the Oregon forearc have no comparable gravity signature and lie directly above a low-velocity wedge observed in controlled-source and local and teleseismic earthquake data. The wedge is presumed to be hydrated forearc mantle. We speculate that these unusual high-amplitude <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are caused in part by serpentinite lying within the hydrated</p> <div class="credits"> <p class="dwt_author">R. J. Blakely; T. M. Brocher; R. E. Wells</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">65</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850023278&hterms=west+north+central&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwest%2Bnorth%2Bcentral"> <span id="translatedtitle">The south-central United States <span class="hlt">magnetic</span> <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A positive <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, which dominates the MAGSAT scalar field over the south-central United States, results from the superposition of <span class="hlt">magnetic</span> effects from several geologic sources and tectonic structures in the crust. The highly <span class="hlt">magnetic</span> basement rocks of this region show good correlation with increased crustal thickness, above average crustal velocity and predominantly negative free-air gravity <span class="hlt">anomalies</span>, all of which are useful constraints for modeling the <span class="hlt">magnetic</span> sources. The positive <span class="hlt">anomaly</span> is composed of two primary elements. The western-most segment is related to middle Proterozoic granite intrusions, rhyolite flows and interspersed metamorphic basement rocks in the Texas panhandle and eastern New Mexico. The <span class="hlt">anomaly</span> and the <span class="hlt">magnetic</span> crust are bounded to the west by the north-south striking Rio Grande Rift. The <span class="hlt">anomaly</span> extends eastward over the Grenville age basement rocks of central Texas, and is terminated to the south and east by the buried extension of the Ouachita System. The northern segment of the <span class="hlt">anomaly</span> extends eastward across Oklahoma and Arkansas to the Mississippi Embayment. It corresponds to a general positive <span class="hlt">magnetic</span> region associated with the Wichita Mountains igneous complex in south-central Oklahoma and 1.2 to 1.5 Ga. felsic terrane to the north.</p> <div class="credits"> <p class="dwt_author">Starich, P. J.; Hinze, W. J.; Braile, L. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">66</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56141869"> <span id="translatedtitle">Marine <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> and <span class="hlt">Magnetization</span> of Oceanic Plate around the Japan Trench in the Northwestern Pacific</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have newly collected dense <span class="hlt">magnetic</span> data around the Japan Trench in the northwestern Pacific. We present characteristics of the complied <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and crustal <span class="hlt">magnetization</span> variation. The Pacific Plate in the study area has a series of parallel <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> (Japanese Lineation Set), identified as chron M14-M7 (140-127 Ma). These <span class="hlt">anomalies</span> are well lineated, in the direction of WSW-ENE,</p> <div class="credits"> <p class="dwt_author">T. Fujiwara; A. Obi; Y. Noda; Y. Kido; M. Nakanishi; N. Hirano; N. Abe; Y. Ogawa</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">67</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUSMGP42A..13K"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">anomalies</span> along the contact between sedimentary and igneous rocks:</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Intrusion of the Liberty Hill granite (South Carolina) into the surrounding shale causes a distinct aureole along the metamorphic contact. The aureole is divided by five isograds, which are the result of a sequence of continuous reactions. One consequence of the continuous reactions is production of contrasting proportion of magnetite and exsolved titanohematite. The continuous change in the relative amounts of these two minerals, controls the <span class="hlt">magnetic</span> properties of the hornfelses. This causes <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> changes associated with the aureole with inflexions occurring at the isograds. The maximum intensity of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> coincides with the maximum abundance of titanohematite. The <span class="hlt">anomaly</span> sharply drops when stable remanence of titanohematite is replaced by unstable remanence of magnetite. <span class="hlt">Magnetic</span> properties of the aureole, which is the contact between igneous and sedimentary rocks, demonstrate an example of <span class="hlt">magnetic</span> remanence acquisition in petrological environment that is likely to occur on planet Mars.</p> <div class="credits"> <p class="dwt_author">Kletetschka, G.; Speer, A. J.; Wasilewski, P. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">68</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUSMGP13A..02G"> <span id="translatedtitle">Spherical Cap Harmonic Modeling of the Antarctic <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During the last decade the Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP) produced a representation of the Antarctic crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. All the ground, marine and aeromagnetic data collected south of 60°S since the IGY 1957-58 were compiled and reprocessed to produce a regional crustal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map with a 5-km grid interval. Satellite-altitude crustal <span class="hlt">anomalies</span> from the CHAMP (400 km) and Ørsted (700 km altitude) missions were also processed and used to fill in regional gaps in the near-surface survey coverage. In this paper, we report on our efforts to develop a Spherical Cap Harmonic (SCH) model of the multi-altitude crustal <span class="hlt">magnetic</span> observations. The purpose of our work is to produce a regional model that will depict the crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> anywhere between the surface and satellite altitude with an accuracy not achieved by global-Earth models. The new SCH model synthesizes almost 50 years of <span class="hlt">magnetic</span> survey observations to facilitate our future studies of the Antarctic <span class="hlt">magnetic</span> field.</p> <div class="credits"> <p class="dwt_author">Gaya-Pique, L. R.; Kim, H.; von Frese, R. R.; Chiappini, M.; Taylor, P. T.; Golynsky, A. V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">69</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51236279"> <span id="translatedtitle">Upper Lithospheric Sources of <span class="hlt">Magnetic</span> and Gravity <span class="hlt">Anomalies</span> of The Fennoscandian Shield</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Magnetic</span> total intensity <span class="hlt">anomalies</span> (DGRF-65), Bouguer <span class="hlt">anomalies</span> (d=2670 kg\\/m3) and geological units from 3400 Ma to present of the Fennoscandian Shield have been digitally compiled and printed as maps 1:2 000 000. Insert maps 1:15,000,000 com- pare <span class="hlt">anomaly</span> components in different source scales: pseudogravimetric <span class="hlt">anomaly</span> ver- sus Bouguer <span class="hlt">anomaly</span>, DGRF-65 <span class="hlt">anomaly</span> versus pseudomagnetic <span class="hlt">anomaly</span>, <span class="hlt">magnetic</span> vertical derivative versus second derivative</p> <div class="credits"> <p class="dwt_author">J. V. Korhonen; T. Koistinen</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">70</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014GeoRL..41.2243J"> <span id="translatedtitle">On vertical electric fields at lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We study the interaction between a <span class="hlt">magnetic</span> dipole mimicking the Gerasimovich <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> on the lunar surface and the solar wind in a self-consistent 3-D quasi-neutral hybrid simulation where ions are modeled as particles and electrons as a charge-neutralizing fluid. Especially, we consider the origin of the recently observed electric potentials at lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. An antimoonward Hall electric field forms in our simulation resulting in a potential difference of <300V on the lunar surface, in which the value is similar to observations. Since the hybrid model assumes charge neutrality, our results suggest that the electric potentials at lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can be formed by decoupling of ion and electron motion even without charge separation.</p> <div class="credits"> <p class="dwt_author">Jarvinen, R.; Alho, M.; Kallio, E.; Wurz, P.; Barabash, S.; Futaana, Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">71</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006AGUFMGP11B0076R"> <span id="translatedtitle">Uncertainty in <span class="hlt">magnetization</span> directions derived from planetary <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in view of numerical experiments with coalesced <span class="hlt">anomalies</span> from Earth</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Martian <span class="hlt">magnetization</span> vectors and paleopole locations determined by different investigators using different methodologies are contradictory. I suggest that one of the reasons for this is that the <span class="hlt">anomalies</span> that are assumed to be caused by a homogeneously <span class="hlt">magnetized</span> source may actually be due to coalescence of multiple crustal sources that may be <span class="hlt">magnetically</span> coherently or incoherently <span class="hlt">magnetized</span> and whose coalescence effects at higher observation altitudes lead to derived <span class="hlt">magnetization</span> directions that are completely different than the ones perceived from lower altitudes. To demonstrate the deleterious effect of the <span class="hlt">anomaly</span> coalescence, I chose marine <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over a small 4 degree by 4 degree area gridded at 0.1 degree spacing in the NW Atlantic Ocean and computed by inverse techniques <span class="hlt">magnetization</span> vectors at surface, 10 km, 20 km, and 50 km altitudes. The analysis considered many indicators of the numerical stability in the inversion of <span class="hlt">magnetization</span> through the equivalent source method, namely the source spacing, the source to observation distance, the mathematical condition number and the rank of the matrix, and also visual characteristics of the observed field and the derived <span class="hlt">magnetization</span> intensity, inclination, and declination. A comparison of the stable solutions at each altitude shows that the derived solutions are completely different from one another. The lowest altitude Mars <span class="hlt">magnetic</span> data are at close to 100 km elevation, but has many gaps, and the cleanest and the most complete <span class="hlt">magnetic</span> data are at close to 400 km elevation. Since it was not even possible to recover similar <span class="hlt">magnetic</span> directions from the surface and 10 km altitude <span class="hlt">anomalies</span>, it should be clear that, unless the Martian <span class="hlt">anomalies</span> are all created by homogeneously <span class="hlt">magnetized</span> contiguous sources whose geometries are known a priori (as in the well-known seamount <span class="hlt">magnetization</span> problem), deriving meaningful <span class="hlt">magnetization</span> directions from the coalesced observed <span class="hlt">anomalies</span> is impossible. While the prospect of understanding the tectonic framework of Mars through the paleomagnetism of its tectonic terranes is tantalizing, the impossibility obtaining meaningful <span class="hlt">magnetic</span> directions from coalesced <span class="hlt">anomalies</span> is reflected in the scattered <span class="hlt">magnetic</span> pole locations obtained by different researchers using different methods.</p> <div class="credits"> <p class="dwt_author">Ravat, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">72</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910067154&hterms=edge+effect&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2522edge%2Beffect%2522"> <span id="translatedtitle">Magsat <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> contrast across Labrador Sea passive margins</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Many passive margins not complicated by nearby anomalous crustal structure have satellite elevation crustal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> contrasts across them that are recognizable in reduced-to-pole versions of the Magsat and POGO data. In the Labrador Sea region this contrast is particularly well developed with strong positive <span class="hlt">anomalies</span> overlying the continental crust of Greenland and eastern Canada and prominent negative <span class="hlt">anomalies</span> situated over the Labrador Sea and Baffin Bay. In this work, forward modeling of the large-scale crustal bodies in this region (continental, oceanic, passive margin, several anomalous structures) was used to show that the Magsat <span class="hlt">anomaly</span> contrast is due simply to the change in crustal susceptibility and thickness at the continental/oceanic crustal transition. Because the thickness varies more than the average susceptibility from continental to oceanic crust, the strong <span class="hlt">anomaly</span> contrast is essentially an edge effect due mostly to the change in crustal structure.</p> <div class="credits"> <p class="dwt_author">Bradley, Lauren M.; Frey, Herbert</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">73</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830005257&hterms=geur&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dgeur"> <span id="translatedtitle">The mineralogy of global <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Curie Balance was brought to operational stage and is producing data of a preliminary nature. Substantial problems experienced in the assembly and initial operation of the instrument were, for the most part, rectified, but certain problems still exist. Relationships between the geology and the gravity and MAGSAT <span class="hlt">anomalies</span> of West Africa are reexamined in the context of a partial reconstruction of Gondwanaland.</p> <div class="credits"> <p class="dwt_author">Haggerty, S. E. (principal investigator)</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">74</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N8616871"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> in the Northeast Atlantic.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A pair of geomagnetic <span class="hlt">anomaly</span> charts printed on a Mercator projection at a scale of 1:2.4 million for the region of the northeast Atlantic from 32 to 62 N and from 0 to 31 W is presented. The charts are compiled from observations along ship's tracks up to...</p> <div class="credits"> <p class="dwt_author">D. G. Roberts M. T. Jones P. M. Hunter</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">75</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://bbs.keyhole.com/ubb/showthreaded.php/Cat/0/Number/1198147/"> <span id="translatedtitle">Google Earth Community: <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> of the Earth</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This is a Google Earth image overlay map of <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> information derived from more than 50 years of aeromagnetic surveys over land areas, research vessel magnetometer traverses at sea, and observations from earth-orbiting satellites, supplemented by <span class="hlt">anomaly</span> values derived from oceanic crustal ages. The objective is to provide an interpretive dimension to surface observations of the Earth's composition and geologic structure. This is a good means of demonstrating how data from minerals contributes to our knowledge of plate tectonics.</p> <div class="credits"> <p class="dwt_author">Community, Google E.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">76</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56254868"> <span id="translatedtitle">Edge detection of <span class="hlt">magnetic</span> body using horizontal gradient of pseudogravity <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Potential field methods are used extensively in mineral exploration. These methods also are used as reconnaissance method in oil and gas exploration. In Contrast with gravity <span class="hlt">anomaly</span> the <span class="hlt">magnetic</span> surveying produces dipolar <span class="hlt">anomaly</span> which is caused complicated interpretation rather than gravity <span class="hlt">anomaly</span>. The observation <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in each location other than <span class="hlt">magnetic</span> poles has displacement rather than causative body. Several</p> <div class="credits"> <p class="dwt_author">K. Alamdar; A. H. Ansari; A. Ghorbani</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">77</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.T23G2679K"> <span id="translatedtitle">The early break-up phase of the South Atlantic - <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, volcanism and kinematics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The South Atlantic has been generally recognized as a prime example for continental break-up with accompanying volcanic activity reflected today in massive seaward dipping reflector sequences (SDRS) in reflection as well as high velocity lower crust in refraction seismic data. The early history of the South Atlantic passive margin evolution is investigated in the view of interlaced <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> related to seafloor <span class="hlt">spreading</span> lineations and <span class="hlt">anomalies</span> caused by seaward-dipping reflector sequences (SDRS). As the Atlantic opened from South to North, the magma-poor segments of the southernmost South Atlantic are also the oldest segments of the Ocean. Therefore, the magma-poor segments on the conjugated margins must be considered crucial in the understanding of the initial phase of <span class="hlt">spreading</span> and rifting concluding in the opening of the South Atlantic. The interpretation of pre-M5n lineations define timing of the termination of excess breakup related volcanic activity and the transition to 'normal' seafloor <span class="hlt">spreading</span>. Termination of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> within SDR wedges point towards a scissor-like succession in volcanic activity from south to north, following the opening of the South Atlantic. Reflection, refraction seismic and potential field data show that while the two conjugated margins share much of their structural features such as segmentation and abundant volcanism, they are by no means perfectly symmetrical. This is for example shown in shelf width, strength of the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> or orientation of break-up related sedimentary basins. From our data, we suggest changes in <span class="hlt">spreading</span> and later rifting direction to be the cause of for these asymmetries. This directional change is also suggested to be responsible for the change in margin character from magma-poor to volcanic rather than solely a spontaneous change in crustal melt-generation. New models for the <span class="hlt">magnetic</span> response of SDRS reveal a high variability within the wedges on either side of the Atlantic and between the conjugated margins. Former identifications of <span class="hlt">anomaly</span> M11r off Cape Town have already been questioned and can now be shown to be caused by structural or <span class="hlt">magnetization</span> variations within SDRS.</p> <div class="credits"> <p class="dwt_author">Koopmann, H.; Schreckenberger, B.; Franke, D.; Becker, K.; Schnabel, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">78</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..1615211H"> <span id="translatedtitle">Lunar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> concentrations at the antipodal regions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The high resolution lunar-wide <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map derived from Lunar Prospector (LP) vector magnetometer data has revealed weak <span class="hlt">anomalies</span> over the nearside large impact basins flooded by mare basalts. Stronger <span class="hlt">anomaly</span> features are observed over many of the Nectarian and Pre-Nectarian aged lunar highlands. In particular, regions antipodal to some of the largest basin-forming impact craters show strong <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> concentrations. Of the 43 basins investigated here, antipodal regions of 9 basins show these anomalous features with strengths in excess of 1-18 nT at LP's mapping altitude (30 km). These distinct anomalous concentrations were previously known to occur only at the antipodes of Imbrium, Orientale, Serenitatis, Crisium and Nectaris basins. The mean <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> strength within each antipodal region, when plotted against increasing age of the antipodes, shows two age groupings with similar <span class="hlt">magnetic</span> behavior. The first age grouping - (Imbrium, Orientale, Serenitatis, Crisium and Nectaris) is of Imbrium to Nectarian in age. This grouping is correlative with peak <span class="hlt">magnetic</span> field enhancements between 3.6 and 3.9 Gyr, inferred from paleomagnetic data from the returned Apollo samples. The second age grouping (Lorentz, Coulomb-Sarton, Tranquillitatis and Cognitum) is of Mid to Early Pre-Nectarian age. This grouping has not been correlated to any known global <span class="hlt">magnetic</span> field enhancement event, and needs further investigation to ascertain the origin of the <span class="hlt">anomalies</span>. Although spatially adjacent, the <span class="hlt">magnetic</span> field signatures of the Serenitatis and Imbrium antipodes exhibit distinct features, supporting the antipodal hypothesis. The absence of appreciable field enhancements at 34 other antipodes, however, indicates the importance of other processes, and superposition effects, that have operated on the Moon during its history.</p> <div class="credits"> <p class="dwt_author">Hemant Singh, Kumar; Kuang, Weijia; Singh, Raghav</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">79</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21457099"> <span id="translatedtitle">SEISMIC DISCRIMINATION OF THERMAL AND <span class="hlt">MAGNETIC</span> <span class="hlt">ANOMALIES</span> IN SUNSPOT UMBRAE</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Efforts to model sunspots based on helioseismic signatures need to discriminate between the effects of (1) a strong <span class="hlt">magnetic</span> field that introduces time-irreversible, vantage-dependent phase shifts, apparently connected to fast- and slow-mode coupling and wave absorption and (2) a thermal <span class="hlt">anomaly</span> that includes cool gas extending an indefinite depth beneath the photosphere. Helioseismic observations of sunspots show travel times considerably reduced with respect to equivalent quiet-Sun signatures. Simulations by Moradi and Cally of waves skipping across sunspots with photospheric <span class="hlt">magnetic</span> fields of order 3 kG show travel times that respond strongly to the <span class="hlt">magnetic</span> field and relatively weakly to the thermal <span class="hlt">anomaly</span> by itself. We note that waves propagating vertically in a vertical <span class="hlt">magnetic</span> field are relatively insensitive to the <span class="hlt">magnetic</span> field, while remaining highly responsive to the attendant thermal <span class="hlt">anomaly</span>. Travel-time measurements for waves with large skip distances into the centers of axially symmetric sunspots are therefore a crucial resource for discrimination of the thermal <span class="hlt">anomaly</span> beneath sunspot umbrae from the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. One-dimensional models of sunspot umbrae based on compressible-radiative-<span class="hlt">magnetic</span>-convective simulations such as by Rempel et al. can be fashioned to fit observed helioseismic travel-time spectra in the centers of sunspot umbrae. These models are based on cooling of the upper 2-4 Mm of the umbral subphotosphere with no significant <span class="hlt">anomaly</span> beneath 4.5 Mm. The travel-time reductions characteristic of these models are primarily a consequence of a Wilson depression resulting from a strong downward buoyancy of the cooled umbral medium.</p> <div class="credits"> <p class="dwt_author">Lindsey, C. [NorthWest Research Associates, 3380 Mitchell Lane, Boulder, CO 80301 (United States); Cally, P. S. [School of Mathematical Sciences, Monash University, Victoria (Australia); Rempel, M. [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green Drive CG1, Boulder, CO 80301 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-08-20</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">80</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17792827"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> over the Mid-Atlantic Ridge near 27{degrees}N.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Ten <span class="hlt">magnetic</span> profiles across the mid-Atlantic ridge near 27 degrees N show trends that are parallel to the ridge axis and symmetrical about the ridge axis. The configuration of <span class="hlt">magnetic</span> bodies that could account for the pattern supports the Vine and Matthews hypothesis for the origin of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over oceanic ridges. A polarity-reversal time scale inferred from models for sea-floor <span class="hlt">spreading</span> in the Pacific-Antarctic ridge and radiometrically dated reversals of the geomagnetic field indicates a <span class="hlt">spreading</span> rate of 1.25 centimeters per year during the last 6 million years and a rate of 1.65 centimeters per year between 6 and 10 million years ago. A similar analysis of more limited data over the mid-Atlantic ridge near 22 degrees N also indicates a change in the <span class="hlt">spreading</span> rate. Here a rate of 1.4 centimeters per year appears to have been in effect during the last 5 million years; between 5 and 9 million years ago, an increased rate of 1.7 centimeters per year is indicated. The time of occurrence and relative magnitude of these changes in the <span class="hlt">spreading</span> rate, about 5 to 6 million years ago and 18 to 27 percent, respectively, accords with the <span class="hlt">spreading</span> rate change implied for the Juan de Fuca ridge in the northeast Pacific. PMID:17792827</p> <div class="credits"> <p class="dwt_author">Phillips, J D</p> <p class="dwt_publisher"></p> <p class="publishDate">1967-08-25</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_3");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return 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showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_6");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">81</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6000136"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">anomalies</span> indicate Gulf of Mexico originated by counterclockwise rotation of Yucatan from Gulf Coast</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Although the Gulf of Mexico is much studied, little is as yet known about the basement underlying its huge thicknesses of Mesozoic and Cenozoic sediment. They suggest that oceanic crust occupies the central gulf and is surrounded by a broad zone of transitional material because they recognize linear <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> that are attributable to sea-floor <span class="hlt">spreading</span> about a pole near 27/sup 0/N, 78/sup 0/W, for a period of roughly 8 m.y. close to the time of the Jurassic-Cretaceous boundary. This interpretation is compatible with several models based upon geologic evidence involving the counterclockwise rotation of Yucatan away from the northern Gulf Coast. Because of low amplitudes and the small number of <span class="hlt">anomalies</span> observed, this cannot be a very strong attribution, but closely spaced, high-resolution <span class="hlt">magnetic</span> surveys particularly in the southwestern gulf would go far toward testing the validity of their interpretation.</p> <div class="credits"> <p class="dwt_author">Shepherd, A.; Hall, S.; Burke, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">82</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19930016012&hterms=PangeA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DPangeA"> <span id="translatedtitle">Improved determination of vector lithospheric <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from MAGSAT data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Scientific contributions made in developing new methods to isolate and map vector <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from measurements made by Magsat are described. In addition to the objective of the proposal, the isolation and mapping of equatorial vector lithospheric Magsat <span class="hlt">anomalies</span>, isolation of polar ionospheric fields during the period were also studied. Significant progress was also made in isolation of polar delta(Z) component and scalar <span class="hlt">anomalies</span> as well as integration and synthesis of various techniques of removing equatorial and polar ionospheric effects. The significant contributions of this research are: (1) development of empirical/analytical techniques in modeling ionospheric fields in Magsat data and their removal from uncorrected <span class="hlt">anomalies</span> to obtain better estimates of lithospheric <span class="hlt">anomalies</span> (this task was accomplished for equatorial delta(X), delta(Z), and delta(B) component and polar delta(Z) and delta(B) component measurements; (2) integration of important processing techniques developed during the last decade with the newly developed technologies of ionospheric field modeling into an optimum processing scheme; and (3) implementation of the above processing scheme to map the most robust <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of the lithosphere (components as well as scalar).</p> <div class="credits"> <p class="dwt_author">Ravat, Dhananjay</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">83</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUFM.S21C..04B"> <span id="translatedtitle">Cascadia Gravity and <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Delineate Hydrated Forearc Mantle</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Very high-amplitude <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> along the eastern margin of the Oregon forearc have no comparable gravity signature and lie directly above a low-velocity wedge observed in controlled-source and local and teleseismic earthquake data. The wedge is presumed to be hydrated forearc mantle. We speculate that these unusual high-amplitude <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are caused in part by serpentinite lying within the hydrated mantle wedge and above the Curie-temperature isotherm for magnetite, a common accessory mineral in serpentinite. To test this idea, we constructed "characteristic" gravity, <span class="hlt">magnetic</span>, pseudogravity, and topographic/bathymetric profiles across the Oregon portion of the Cascadia subduction zone: We extracted 11 east-west profiles, linearly interpolated each to a common sample interval using the deformation front offshore and the axis of the Cascade arc onshore as tie points, and stacked them to attenuate <span class="hlt">anomalies</span> due to three-dimensional sources. We then modeled the characteristic gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> using published seismic velocity and thermal models and density values as constraints. The forearc portion of the model includes a thick Siletzia (>12 km) section underlain by lower crust, upper mantle, and subducting lithosphere. The gravity and <span class="hlt">magnetic</span> profiles and modeled crustal geology are compatible with a low-density (2700 kg/m3), high-<span class="hlt">magnetization</span> (2.7 A/m) wedge corresponding in shape, location, and depth range (35 to 55 km) to the low-velocity zone identified in seismic models. We interpret the potential-field <span class="hlt">anomalies</span> as evidence for serpentinized forearc mantle at depths above the Curie-temperature isotherm. Thus determined, <span class="hlt">magnetic</span> and pseudogravity <span class="hlt">anomalies</span> allow us to map the presence of serpentinized mantle along the length of the Cascadia subduction zone. Serpentinized mantle is best expressed geophysically in Oregon, along a narrow swath from the Klamath Mountains to the Columbia River, a region with a dearth of both upper- and lower-plate earthquakes. We speculate that a well-developed serpentinite wedge beneath the Oregon forearc reduces friction on the downgoing slab and reduces margin-normal stress on the upper plate. The lack of high-amplitude <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in Washington suggests either that hydrated mantle is not as well developed in Washington, or that it lies deeper than the Curie-temperature isotherm.</p> <div class="credits"> <p class="dwt_author">Blakely, R. J.; Brocher, T. M.; Wells, R. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">84</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998EOSTr..79..290C"> <span id="translatedtitle">Effort to develop <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> database aids Antarctic research</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Antarctic is the subject of considerable international interest because its geology records the evolution of Gondwana and Rodinia. The geology of the Antarctic is poorly understood, however, due to the region's nearly ubiquitous cover of snow, ice, and water and its harsh environment, which severely restricts field investigations.<span class="hlt">Magnetic</span> <span class="hlt">anomaly</span> data greatly aid geologic studies of the Antarctic, and hence many near-surface <span class="hlt">magnetic</span> surveys have been carried out by the international community for site-specific geologic objectives since the International Geophysical Year of 1957-1958. At the first workshop of the Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP) in Cambridge, UK, it became clear that the data from these <span class="hlt">magnetic</span> surveys can also be combined into a regional compilation to extend their usefulness for geologic studies of the Antarctic [Johnson et al., 1996; 1997].</p> <div class="credits"> <p class="dwt_author">Chiappini, Massimo; von Frese, Ralph R. B.; Ferris, Julie</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">85</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/ofr20071047SRP093"> <span id="translatedtitle">The next generation Antarctic digital <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">S (Golynsky et al., 2001). This map synthesized over 7.1 million line-kms of survey data available up through 1999 from marine, airborne and Magsat satellite observations. Since the production of the initial map, a large number of new marine and airborne surveys and improved <span class="hlt">magnetic</span> observations from the Ørsted and CHAMP satellite missions have become available. In addition, an improved core field model for the Antarctic has been developed to better isolate crustal <span class="hlt">anomalies</span> in these data. The next generation compilation also will likely represent the <span class="hlt">magnetic</span> survey observations of the region in terms of a high-resolution spherical cap harmonic model. In this paper, we review the progress and problems of developing an improved <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map to facilitate studies of the Antarctic crustal <span class="hlt">magnetic</span> field</p> <div class="credits"> <p class="dwt_author">von Frese, R.R.B; Golynsky, A.V.; Kim, H.R.; Gaya-Piqué, L.; Thébault, E.; Chiappinii, M.; Ghidella, M.; Grunow, A.; ADMAP Working Group</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">86</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/ofr20071047SRP050"> <span id="translatedtitle">New <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map of East Antarctica and surrounding regions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">community over East Antarctica and surrounding regions, significantly upgrade the Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP) compilation and lead to substantial improvements in <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> pattern recognition. New data have been matched in one inverse operation by minimizing the data differences for the areas of overlap. The aeromagnetic data show many previously unknown <span class="hlt">magnetic</span> patterns, lineaments and trends, defining the spatial extent of Ferrar volcanics and plutonic Granite Harbour Intrusives in the Transantarctic Mountains and previously unknown tectonic trends of the East Antarctic craton. Regional aeromagnetic investigations have successfully delineated Early Paleozoic inherited crustal features along the flanks of the West Antarctic Rift System and the southern boundary of the Archean Ruker Terrane in the Prince Charles Mountains. <span class="hlt">Magnetic</span> records along the East Antarctic continental margin provide new constraints on the breakup of Gondwana.</p> <div class="credits"> <p class="dwt_author">Golynsky, A.; Blankenship, D.; Chiappini, M.; Damaske, D.; Ferraccioli, F.; Finn, C.; Golynsky, D.; Goncharov, A.; Ishihara, T.; Ivanov, S.; Jokat, W.; Kim, H.R.; König, M.; Masolov, V.; Nogi, Y.; Sand, M.; Studing, M.; ADMAP Working Group</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">87</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20010013023&hterms=classifying+rocks&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dclassifying%2Brocks"> <span id="translatedtitle">Potential Mars 2001 Sites Coincident with <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Of the areas that meet the engineering criteria for MSP 01, only two are coincident with <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> measured by the MAG/ER instrument on MGS. Area A is centered on about 10 deg S, 202 deg W and extends from about 7.5 deg S to 15 S. This area is associated with three bands of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, two with positive values surrounding an area with negative values. Area B corresponds with a circular high positive <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and is centered at 13.5 deg S, 166 deg W. In addition to <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, the proposed sites have other attributes that make then attractive from of standpoint of meeting the objectives of the Mars Program. The landing site candidates meet the engineering requirements outlined on the Mars '01 landing site page htip://mars.jpl.nasa.gov/2001/landingsite. These are (source of data in parentheses): latitude between 3 deg N and 12 deg S, rock abundance between 5-10% (IRTM), fine-component thermal inertia > 4 cgs units (IRTM), topography < 2.5 km (MOLA). There are three exceptions: 1) Area B contains sites that lie up to about 15 deg S, 2) some sites are considered that have rock abundance values of 3-13%. 3) High resolution Viking coverage may not be available. These exceptions will be noted.</p> <div class="credits"> <p class="dwt_author">Gilmore, M. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">88</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3778608"> <span id="translatedtitle"><span class="hlt">Magnetic</span> resonance imaging in obstructive M?llerian <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Herlyn-Werner-Wunderlich (HWW) syndrome is a very rare congenital <span class="hlt">anomaly</span> of the urogenital tract involving Müllerian ducts and Wolffian structures. It is characterized by the triad of didelphys uterus, obstructed hemivagina, and ipsilateral renal agenesis. <span class="hlt">Magnetic</span> resonance imaging (MRI) is a sensitive, non-invasive diagnostic modality for demonstrating anatomic variation and associated complications.</p> <div class="credits"> <p class="dwt_author">Sen, Kamal Kumar; Balasubramaniam, Dhivya; Kanagaraj, Vikrant</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">89</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/doepatents/biblio/873116"> <span id="translatedtitle">Low energy <span class="hlt">spread</span> ion source with a coaxial <span class="hlt">magnetic</span> filter</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p class="result-summary">Multicusp ion sources are capable of producing ions with low axial energy <span class="hlt">spread</span> which are necessary in applications such as ion projection lithography (IPL) and radioactive ion beam production. The addition of a radially extending <span class="hlt">magnetic</span> filter consisting of a pair of permanent <span class="hlt">magnets</span> to the multicusp source reduces the energy <span class="hlt">spread</span> considerably due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. A coaxial multicusp ion source designed to further reduce the energy <span class="hlt">spread</span> utilizes a cylindrical <span class="hlt">magnetic</span> filter to achieve a more uniform axial plasma potential distribution. The coaxial <span class="hlt">magnetic</span> filter divides the source chamber into an outer annular discharge region in which the plasma is produced and a coaxial inner ion extraction region into which the ions radially diffuse but from which ionizing electrons are excluded. The energy <span class="hlt">spread</span> in the coaxial source has been measured to be 0.6 eV. Unlike other ion sources, the coaxial source has the capability of adjusting the radial plasma potential distribution and therefore the transverse ion temperature (or beam emittance).</p> <div class="credits"> <p class="dwt_author">Leung, Ka-Ngo (Hercules, CA); Lee, Yung-Hee Yvette (Berkeley, CA)</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">90</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/7199827"> <span id="translatedtitle">Tune <span class="hlt">spread</span> due to <span class="hlt">magnetic</span> multipoles in RHIC</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Analytical expressions have been obtained of the amplitude and momentum dependence of the transverse tunes due to <span class="hlt">magnetic</span> multipoles and orbit misalignment. Based on these expressions, compensation methods are developed to minimize the tune <span class="hlt">spread</span> in RHIC with the {beta}* = lm design.</p> <div class="credits"> <p class="dwt_author">Wei, J.; Harrison, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">91</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10169917"> <span id="translatedtitle">Tune <span class="hlt">spread</span> due to <span class="hlt">magnetic</span> multipoles in RHIC</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Analytical expressions have been obtained of the amplitude and momentum dependence of the transverse tunes due to <span class="hlt">magnetic</span> multipoles and orbit misalignment. Based on these expressions, compensation methods are developed to minimize the tune <span class="hlt">spread</span> in RHIC with the {beta}* = lm design.</p> <div class="credits"> <p class="dwt_author">Wei, J.; Harrison, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">92</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE85016552"> <span id="translatedtitle">Energy Efficient Light Bulbs: The <span class="hlt">Magnetic</span> Arc <span class="hlt">Spreading</span> Fluorescent Lamp.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The contractor developed an energy efficient light bulb based upon the <span class="hlt">spreading</span> of the plasma via a <span class="hlt">magnetic</span> field. A non-standard bowl-shaped lamp was designed, and, due to the large glass seal area, considerable difficulty was encountered in applying t...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">93</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19770018759&hterms=african+cities&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dafrican%2Bcities"> <span id="translatedtitle">On the origin of the Bangui <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, central African empire</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A large <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> was recognized in satellite magnetometer data over the Central African Empire in central Africa. They named this <span class="hlt">anomaly</span> the Bangui <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> due to its location near the capital city of Bangui, C.A.E. Because large crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are uncommon, the origin of this <span class="hlt">anomaly</span> has provoked some interest. The area of the <span class="hlt">anomaly</span> was visited to make ground <span class="hlt">magnetic</span> measurements, geologic observations, and in-situ <span class="hlt">magnetic</span> susceptibility measurements. Some rock samples were also collected and chemically analyzed. The results of these investigations are presented.</p> <div class="credits"> <p class="dwt_author">Marsh, B. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">94</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFM.P23C1272H"> <span id="translatedtitle">Spectral and <span class="hlt">Magnetic</span> Studies of Lesser-Known Lunar <span class="hlt">Magnetic</span> and Albedo <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The origin of the lunar swirls is an outstanding puzzle in lunar geoscience. In addition, the swirls lie at the intersection of broader issues in planetary science, including planetary <span class="hlt">magnetism</span> (e.g., the origin of the <span class="hlt">magnetized</span> crust via core dynamo versus impact processes) and the relative importance of solar wind exposure versus micrometeoroid bombardment in producing the optical effects of space weathering. Many of the unusual high-albedo features known as lunar swirls are associated with crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, and many of the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are found near the antipodes of major impact basins. The leading hypotheses that have been advanced for the formation of the swirls are: (a) regolith disturbance caused by the relatively recent impact of a comet coma, cometary fragments or cometary meteor swarms; and (b) atypical space weathering as a result of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> shielding the surface from solar wind ion bombardment. Apollo subsatellite instruments, whose coverage was limited to equatorial and mid-latitudes, first revealed the existence of lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. The Lunar Prospector (LP) mission provided global data and has led to the discovery of additional regions of <span class="hlt">magnetized</span> crust. We have conducted a series of studies on lunar <span class="hlt">magnetic</span> and albedo <span class="hlt">anomalies</span> using LP magnetometer data and Clementine multispectral images. Three of these <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> have only been recently identified. Newly discovered <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> near the craters Abel, Stofler, and Hartwig do not appear to harbor unusual albedo markings. The <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> near Rima Sirsalis has long been known from Apollo data. A small sinuous swirl to the northwest may be related to the Sirsalis <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> or could be a southern extension of Reiner Gamma. Our examination of images for Rima Sirsalis has led to the identification of an additional loop-shaped marking on Oceanus Procellarum and some possible anomalous bright patches in the nearby highlands. Our new LP maps of scalar field strength show that previously identified swirls near Hopmann, Firsov, and in western Mare Moscoviense do coincide with <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. On the basis of this work, our preliminary finding is that most, perhaps all, swirl-like albedo patterns are co-located with crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, but not all <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> exhibit unusual albedo patterns. Plots of Clementine color ratio versus reflectance for small areas show spectral trends that are consistent with a lesser degree of maturation for surfaces within the high-reflectance portions of swirls compared with the normal background, which is consistent with either mode of formation discussed above. Additional analysis of Clementine spectral data, combined with new observations from LRO and other spacecraft can help to further characterize these enigmatic features.</p> <div class="credits"> <p class="dwt_author">Hawke, B. R.; Blewett, D. T.; Coman, E. I.; Purucker, M. E.; Gillis-Davis, J. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">95</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.agu.org/journals/jz/v066/i011/JZ066i011p03793/JZ066i011p03793.pdf"> <span id="translatedtitle">Depth to Sources of <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Absiract. The characteristics of several long <span class="hlt">magnetic</span> total field intensity profiles have been determined. Only track lines which were nearly straight and longer than 2000 miles were considered. First, the centered dipole field total intensity was subtracted from the measured total intensity to obtain a real nondipole field. A smooth curve was then drawn through this nondipole field using a</p> <div class="credits"> <p class="dwt_author">Leroy R. Alldredge; Gerald D. Van Voorhis</p> <p class="dwt_publisher"></p> <p class="publishDate">1961-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">96</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUSMGP41A..07R"> <span id="translatedtitle">Mapping and Modeling of Major Martian <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">As summarized recently by Connerney et al. (GRL, v. 28, p. 4015, 2001), the Mars Global Surveyor magnetometer experiment has obtained nearly uniform global measurements of the Martian crustal <span class="hlt">magnetic</span> field at mapping orbit altitudes (370 - 438 km) since March 1999. In this paper, we report mapping of these data and modeling of selected <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> using methods introduced earlier by Hood and Zakharian (J. Geophys. Res., v. 206, p. 14601, 2001). Major goals are to estimate lower limits on bulk intensities of <span class="hlt">magnetization</span>, approximate bulk directions of <span class="hlt">magnetization</span>, and corresponding paleomagnetic pole positions for relatively isolated <span class="hlt">anomaly</span> sources. A single, relatively isolated, <span class="hlt">anomaly</span> located at 14oS, 166oW (194oE) was selected for detailed modeling. This <span class="hlt">anomaly</span> has a total field magnitude at 383 km altitude of 240 nT and is therefore one of the strongest on Mars. As a source model, we assume a uniformly <span class="hlt">magnetized</span> circular plate located at the martian surface with an unknown thickness and radius. Results show that the surface plate required to produce these fields has a radius of 390 +/- 60 km and a dipole moment per unit area of 1.9 +/- 0.5 x 105 Amperes (19000 +/- 5000 G-cm). The inferred bulk <span class="hlt">magnetization</span> vector has direction angles of ? =25o+/- 15o, ? =270o+/- 30o, where ? is the angle between the local radial direction and the moment vector and ? is the azimuth of the surface projection of the moment vector measured counterclockwise (looking down) about the radius vector from the local eastward direction. The corresponding north paleomagnetic pole (calculated following Hood and Zakharian) is centered on 28o +/- 10oN, 200o +/- 30o E longitude (160o +/- 30o W longitude). For comparison, we have previously modeled two <span class="hlt">anomalies</span> in the northern polar region (ref. 2) with south paleomagnetic poles centered at 38oN, 141oW and at 61oN, 136oW, respectively. Thus, the north paleomagnetic pole position estimated for the <span class="hlt">anomaly</span> studied here is in the same region as the south paleomagnetic poles estimated earlier for the two <span class="hlt">anomalies</span> studied by Hood and Zakharian.</p> <div class="credits"> <p class="dwt_author">Richmond, N.; Hood, L. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">97</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE95009698"> <span id="translatedtitle">Airborne detection of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> associated with soils on the Oak Ridge Reservation, Tennessee.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Reconnaissance airborne geophysical data acquired over the 35,000-acre Oak Ridge Reservation (ORR), TN, show several <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over undisturbed areas mapped as Copper Ridge Dolomite (CRD). The <span class="hlt">anomalies</span> of interest are most apparent in <span class="hlt">magnetic</span> g...</p> <div class="credits"> <p class="dwt_author">W. E. Doll L. P. Beard J. M. Helm</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">98</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70012575"> <span id="translatedtitle">Lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> detected by the Apollo substatellite magnetometers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Properties of lunar crustal <span class="hlt">magnetization</span> thus far deduced from Apollo subsatellite magnetometer data are reviewed using two of the most accurate presently available <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps - one covering a portion of the lunar near side and the other a part of the far side. The largest single <span class="hlt">anomaly</span> found within the region of coverage on the near-side map correlates exactly with a conspicuous, light-colored marking in western Oceanus Procellarum called Reiner Gamma. This feature is interpreted as an unusual deposit of ejecta from secondary craters of the large nearby primary impact crater Cavalerius. An age for Cavalerius (and, by implication, for Reiner Gamma) of 3.2 ?? 0.2 ?? 109 y is estimated. The main (30 ?? 60 km) Reiner Gamma deposit is nearly uniformly <span class="hlt">magnetized</span> in a single direction, with a minimum mean <span class="hlt">magnetization</span> intensity of ???7 ?? 10-2 G cm3/g (assuming a density of 3 g/cm3), or about 700 times the stable <span class="hlt">magnetization</span> component of the most <span class="hlt">magnetic</span> returned samples. Additional medium-amplitude <span class="hlt">anomalies</span> exist over the Fra Mauro Formation (Imbrium basin ejecta emplaced ???3.9 ?? 109 y ago) where it has not been flooded by mare basalt flows, but are nearly absent over the maria and over the craters Copernicus, Kepler, and Reiner and their encircling ejecta mantles. The mean altitude of the far-side <span class="hlt">anomaly</span> gap is much higher than that of the near-side map and the surface geology is more complex, so individual <span class="hlt">anomaly</span> sources have not yet been identified. However, it is clear that a concentration of especially strong sources exists in the vicinity of the craters Van de Graaff and Aitken. Numerical modeling of the associated fields reveals that the source locations do not correspond with the larger primary impact craters of the region and, by analogy with Reiner Gamma, may be less conspicuous secondary crater ejecta deposits. The reason for a special concentration of strong sources in the Van de Graaff-Aitken region is unknown, but may be indirectly related to the existence of strongly modified crustal terrain which also occurs in the same region. The inferred directions of <span class="hlt">magnetization</span> for the several sources of the largest <span class="hlt">anomalies</span> are highly inclined with respect to one another, but are generally depleted in the north-south direction. The north-south depletion of <span class="hlt">magnetization</span> intensity appears to continue across the far-side within the region of coverage. The mechanism of <span class="hlt">magnetization</span> and the origin of the <span class="hlt">magnetizing</span> field remain unresolved, but the uniformity with which the Reiner Gamma deposit is apparently <span class="hlt">magnetized</span>, and the north-south depletion of <span class="hlt">magnetization</span> intensity across a substantial portion of the far side, seem to require the existence of an ambient field, perhaps of global or larger extent. The very different inferred directions of <span class="hlt">magnetization</span> possessed by nearly adjacent sources of the Van de Graaff-Aitken <span class="hlt">anomalies</span>, and the depletion in their north-south component of <span class="hlt">magnetization</span>, do not favor an internally generated dipolar field oriented parallel to the present spin axis. A variably oriented interplanetary <span class="hlt">magnetizing</span> field that was intrinsically strong or locally amplified by unknown surface processes is least inconsistent with the data. ?? 1979.</p> <div class="credits"> <p class="dwt_author">Hood, L. L.; Coleman, Jr. , P. J.; Russell, C. T.; Wilhelms, D. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">99</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6945209"> <span id="translatedtitle">Gravity, <span class="hlt">magnetics</span> point to volcanic origin for Oklahoma's Ames <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This paper reports that a recent publication of high production volumes of Arbuckle oil and gas at Ames in Major County, Okla., favors an astrobleme as the cause of structural deformation. The feature expresses a distinct circular geologic depression on the top of the Sylvan shale in Townships 20-21 North, Ranges 9-10 West. Consolidated Geophysical Surveys presents gravity and vertical intensity <span class="hlt">magnetic</span> data in support of a volcanic origin. Three stages of volcanic activity are projected. CGS' interest in the cause of the Ames <span class="hlt">anomaly</span> was founded initially in its study of the reported Red Wing Creek (North Dakota) astrobleme during the company's extensive gravity and <span class="hlt">magnetic</span> exploration in the Williston basin in the 1980s. The regional gravity and <span class="hlt">magnetic</span> gradients over the Red Wing Creek <span class="hlt">anomaly</span> bear no resemblance to the Ames feature.</p> <div class="credits"> <p class="dwt_author">Roemer, C.D.; Roemer, C.; Williams, K. (Consolidated Geophysical Surveys, Tulsa, OK (United States))</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-06-29</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">100</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011JGRE..116.2002B"> <span id="translatedtitle">Lunar swirls: Examining crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and space weathering trends</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have used multispectral images from Clementine and data from Lunar Prospector's magnetometer to conduct a survey of lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, prominent lunar swirls, and lesser known swirl markings to provide new information on the nature of swirls and their association with <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. We find that all swirls and swirl-like albedo patterns are associated with areas of <span class="hlt">magnetized</span> crust, but not all areas of <span class="hlt">magnetized</span> crust are colocated with swirl-like albedo <span class="hlt">anomalies</span>. All observed swirls exhibit spectral characteristics similar to immature material and generally have slightly lower FeO values compared with their surroundings as determined with a multispectral iron-mapping method. We discuss these results in relation to the various hypotheses for swirl formation. The comet impact hypothesis for lunar swirls would not predict a difference in the spectrally determined FeO content between swirls and nearby ordinary surfaces. The compositional difference could be explained as a consequence of (1) <span class="hlt">magnetic</span> shielding of the surface from the solar wind, which could produce anomalous space weathering (little darkening with limited reddening) and potentially alter the predictions of the multispectral iron-mapping algorithm while the compositional contrast could be enhanced by delivery of lower-FeO ejecta from outside the swirl; and (2) accumulation of fine plagioclase-rich dust moving under the influence of electric fields induced by solar wind interactions with a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. Therefore, we cannot at present clearly distinguish between the solar wind shielding and electrostatic dust accumulation models for swirl formation. We describe future measurements that could contribute to solution of the puzzle of swirl origin.</p> <div class="credits"> <p class="dwt_author">Blewett, David T.; Coman, Ecaterina I.; Hawke, B. Ray; Gillis-Davis, Jeffrey J.; Purucker, Michael E.; Hughes, Christopher G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-02-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_4");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">101</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMGP13A1116K"> <span id="translatedtitle">High <span class="hlt">magnetic</span> susceptibility granodiorite as a source of surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the King George Island, Antarctica</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Change in plate motion produces convergence of the two oceanic lithospheres and the formation of volcanic island arcs above the subducted older and thicker plate. The association of calc-alkaline diorites to tonalites and granodiorites (ACG) is typical plutonic rocks of the volcanic arcs. In the many island arcs that surround the Pacific Ocean, ACG generally forms shallow level plutons and is closely associated with volcanic rocks. The Japan Arc setting had occurred the emplacement of the highly <span class="hlt">magnetic</span> granitoid along the fore-arc basin before back-arc <span class="hlt">spreading</span> at middle Miocene, showing a linear positive <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. Similar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> have also been exhibited along the Circum-Pacific Belt. Along East Antarctica, it is well known that the South Shetland Islands have been formed by back-arc <span class="hlt">spreading</span> related to the subduction along the South Shetland trench during the late Cretaceous and middle Miocene. Moreover, geology in the South Shetland Islands consists of lava flows with subordinate pyroclastic deposits, intrusive dykes-sills, granitic plutons, displaying a typical subduction-related calc-alkaline volcanic association. However, there is little report on the presence of fore-arc granitoid. Here we report the distribution and structure of the granitic plutons around Marian Cove in the King George Island, South Shetland, East Antarctica by surface geological survey and <span class="hlt">magnetic</span> anisotropic studies. Then we compare the distribution of granitic plutons with surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> through our ship-borne and foot-borne <span class="hlt">magnetic</span> surveys. The granitic plutons are distributed only shallow around the Marian cove in the King George Island, and the plutons had been intruded in the Sejong formation with pyroclastic deposits and basaltic/rhyoritic lavas, suggesting the post back-arc <span class="hlt">spreading</span>. We sampled 8 plutons, 12 basaltic lavas and 6 andestic dykes, all located within four kilometer radius from the Korean Antarctic research station (King Sejong station) in the western side of King George Island. The plutonic rocks of diorite and granodiorite show high values of bulk <span class="hlt">magnetic</span> susceptibility of c.a. 0.01-0.4 SI, appearing to be the source of positive <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. We also revealed the preferred petrofabric lineation directions at the sites using anisotropy of <span class="hlt">magnetic</span> susceptibility (AMS). The AMS showed the plutonic rocks represent the vertical intrusion from the deep seated magma. Our optical microscope observation verified the maximum AMS orientation is parallel to the preferred alignment of framework-forming plagioclase, suggesting the alignment of euhedral magnetite grains along the long-axes of plagioclases. Our ship-borne and foot-borne surveys of geomagnetic filed <span class="hlt">anomaly</span> agree well with the distribution of the plutonic rocks, revealing the possible origin of surface <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. These suggests that the plutons in this area may be included ACG, and this <span class="hlt">magnetic</span> surveys is proposed to infer the availability to find out the presence of granitoid.</p> <div class="credits"> <p class="dwt_author">Kon, S.; Nakamura, N.; Funaki, M.; Sakanaka, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">102</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=ufo&id=EJ588347"> <span id="translatedtitle"><span class="hlt">Anomalies</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">This theme issue on <span class="hlt">anomalies</span> includes Web sites, CD-ROMs and software, videos, books, and additional resources for elementary and junior high school students. Pertinent activities are suggested, and sidebars discuss UFOs, animal <span class="hlt">anomalies</span>, and <span class="hlt">anomalies</span> from nature; and resources covering unexplained phenonmenas like crop circles, Easter Island,…</p> <div class="credits"> <p class="dwt_author">Online-Offline, 1999</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">103</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP13A1141F"> <span id="translatedtitle">Marine <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and <span class="hlt">magnetization</span> of subducting Pacific Plate around the Japan Trench</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We studied marine <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in the northwestern margin of the Pacific Plate off Japan to examine whether the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> varies due to tectonic phenomenon caused by the plate subduction. For the sake of this study, we newly collected <span class="hlt">magnetic</span> data aboard JAMSTEC cruises in the seaward area where was sparsely surveyed, and made a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map by compilation of our data, data published by Geological Survey of Japan, and data from NGDC. The seafloor of the seaward slope of the Japan Trench is characterized by a series of parallel <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> (Japanese Lineation Set) during M11-M7 (135-127 Ma). The <span class="hlt">anomalies</span> are well lineated and have high-amplitudes of ~500-1000 nT peak-to-trough. The amplitudes of the <span class="hlt">anomalies</span> gradually decay to the landward from the trench axis associated with the plate subduction. Equivalent <span class="hlt">magnetization</span> was calculated from the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> to correct for effects of seafloor topography and increasing depth of subducting plate. Densely distributed seismic survey profiles in the study area enabled us to constrain the depth of the plate. On the seaward trench slope from the trench axis to a distance of ca. 100 km, horst-graben structure is developed and large steps grow associated with plate bending and normal faulting, which would cause some kind of destruction and mechanical disorganization of the <span class="hlt">magnetic</span> layer by faulting. However, the <span class="hlt">magnetization</span> is not influenced apparently there. The <span class="hlt">magnetization</span> gradually decreases as the plate subduction proceeded. The apparent decay could reflect destruction and mechanical disorganization and/or chemical demagnetization of the topmost part of the oceanic crust along the plate boundary. The <span class="hlt">magnetization</span> in reverse polarity decays larger than that in normal polarity. The result is indicative of reduction of remanence in the oceanic crust and induced <span class="hlt">magnetization</span> possibly due to serpentinized uppermost mantle.</p> <div class="credits"> <p class="dwt_author">Fujiwara, T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">104</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=ADA236750"> <span id="translatedtitle">Residual Total Field <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map of NOARL's <span class="hlt">Magnetic</span> Observatory,</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The purpose of this survey is to create an accurate residual <span class="hlt">magnetic</span> contour map of the <span class="hlt">Magnetic</span> Observatory area at Stennis Space Center. Measurements were completed covering the observatory grounds. A map of the <span class="hlt">magnetic</span> residuals is presented.</p> <div class="credits"> <p class="dwt_author">C. R. Estes W. E. Avera</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">105</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/21691766"> <span id="translatedtitle">Tracking pigeons in a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and in <span class="hlt">magnetically</span> "quiet" terrain.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Pigeons were released at two sites of equal distance from the loft, one within a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, the other in <span class="hlt">magnetically</span> quiet terrain, and their tracks were recorded with the help of GPS receivers. A comparison of the beginning of the tracks revealed striking differences: within the <span class="hlt">anomaly</span>, the initial phase lasted longer, and the distance flown was longer, with the pigeons' headings considerably farther from the home direction. During the following departure phase, the birds were well homeward oriented at the <span class="hlt">magnetically</span> quiet site, whereas they continued to be disoriented within the <span class="hlt">anomaly</span>. Comparing the tracks in the <span class="hlt">anomaly</span> with the underlying <span class="hlt">magnetic</span> contours shows considerable differences between individuals, without a common pattern emerging. The differences in <span class="hlt">magnetic</span> intensity along the pigeons' path do not differ from a random distribution of intensity differences around the release site, indicating that the <span class="hlt">magnetic</span> contours do not directly affect the pigeons' routes. Within the <span class="hlt">anomaly</span>, pigeons take longer until their flights are oriented, but 5 km from the release point, the birds, still within the <span class="hlt">anomaly</span>, are also significantly oriented in the home direction. These findings support the assumption that <span class="hlt">magnetically</span> anomalous conditions initially interfere with the pigeons' navigational processes, with birds showing rather individual responses in their attempts to overcome these problems. PMID:21691766</p> <div class="credits"> <p class="dwt_author">Schiffner, Ingo; Fuhrmann, Patrick; Wiltschko, Roswitha</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">106</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004EP%26S...56..955K"> <span id="translatedtitle">Application of satellite <span class="hlt">magnetic</span> observations for estimating near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Regional to continental scale <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps are becoming increasingly available from airborne, ship-borne, and terrestrial surveys. Satellite data are commonly considered to fill the coverage gaps in regional compi-lations of these near-surface surveys. For the near-surface Antarctic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map being produced by the Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP), we show that near-surface <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> estimation is greatly enhanced by the joint inversion of the near-surface data with Ørsted satellite observations compared to Magsat data that have order-of-magnitude greater measurement errors, albeit collected at much lower orbital alti-tudes. The CHAMP satellite is observing the geomagnetic field with the same measurement accuracy as the Ørsted mission, but at the lower orbital altitudes covered by Magsat. Hence, additional significant improvement in predict-ing near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can result as lithospheric <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data from the CHAMP mission become available. Our analysis also suggests that a further order-of-magnitude improvement in the accuracy of the magnetometer measurements at minimum orbital altitude may reveal considerable new insight into the <span class="hlt">magnetic</span> properties of the lithosphere.</p> <div class="credits"> <p class="dwt_author">Kim, H. R.; von Frese, R. R. B.; Golynsky, A. V.; Taylor, P. T.; Kim, J. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">107</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP11A..03H"> <span id="translatedtitle">Deep-sea Vector <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> over the Bayonnaise Knoll Caldera (Izu-Ogasawara Arc) (Invited)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Bayonnaise Knoll caldera is located on the eastern margin of the backarc rift zone of the Izu-Ogasawara island arc. The caldera rim is ~3 km in diameter and 100-200 m high from the caldera floor 840-920 m deep. A large active hydrothermal field associated with sulfide deposit, called the Hakurei site, has been found at the foot of the southeastern caldera wall. We conducted deep-sea <span class="hlt">magnetic</span> measurements using autonomous underwater vehicles to map ~75 % of an area 3 km by 4 km in the caldera. The <span class="hlt">magnetic</span> vector field data were collected at 40-150 m altitude along the survey lines spaced 80-200 m apart. We improved the conventional correction method applied for removing the effect of vehicle <span class="hlt">magnetization</span>, which greatly enhanced the precision of the resulting vector <span class="hlt">anomalies</span> and allowed us to use the vector <span class="hlt">anomaly</span> instead of the total intensity <span class="hlt">anomaly</span> for inversion analysis. The <span class="hlt">magnetization</span> distribution obtained using the vector <span class="hlt">anomaly</span> was significantly different from the one obtained using the total intensity <span class="hlt">anomaly</span>, especially in areas where the survey tracks were widely spaced. The aliasing effect appears in areas of sparse data distribution, and the <span class="hlt">magnetic</span> field is more correctly calculated from the vector <span class="hlt">anomaly</span> than the total intensity <span class="hlt">anomaly</span>. The <span class="hlt">magnetization</span> distribution in the caldera has two major features: a ~1.5-km wide belt of high <span class="hlt">magnetization</span>, trending NNW-SSE through the caldera, and a clear low <span class="hlt">magnetization</span> zone, ~300 m x ~500 m wide, extending over the Hakurei site. The high <span class="hlt">magnetization</span> belt is considered to reflect basaltic volcanism associated with the backarc rifting that occurred after the formation of the Bayonnaise Knoll. The low <span class="hlt">magnetization</span> zone is interpreted as the alteration zone resulting from the hydrothermal activity. Several zones of localized high <span class="hlt">magnetization</span> are recognized within the high <span class="hlt">magnetization</span> belt, some of them in the caldera wall adjacent to the low <span class="hlt">magnetization</span> zone of the Hakurei site. We speculate that intensive magma intrusion occurred beneath the caldera wall and has provided the heat to generate hydrothermal fluid, which has been spouting out through the caldera wall faults. The surface expression of the vent field extends beyond the alteration zone inferred from the <span class="hlt">magnetization</span> distribution, <span class="hlt">spreading</span> upwards in the caldera wall. High-resolution topography around the Hakurei site indicates that the hydrothermal vents are generally distributed over a landform of slope failure. These observations would imply that hydrothermal fluid rising up in the up-flow zone moves laterally as well when it comes near the seafloor, probably along numerous fractures and fissures in the caldera wall. The distribution of pre-existing faults and fractures may rather control the fluid flow pathways in the shallow part and condition the surface extent of the vent field.</p> <div class="credits"> <p class="dwt_author">Honsho, C.; Ura, T.; Kim, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">108</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EGUGA..1214689L"> <span id="translatedtitle">The Russian contribution in WDMAM-2011 <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and <span class="hlt">anomalies</span> of satellite Champ</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In VSEGEI is created the renovated digital cartographical model of an anomalous <span class="hlt">magnetic</span> field (AMF) of territory of Russia and adjacent aquatory of scale 1:2 500000 on the basis of the available base summary digital materials prepared at various times by two organizations: VSEGEI and VNIIOkeangeologia. For this purpose uniform technological rules which have provided satisfactory synthesis of digital data files of an anomalous <span class="hlt">magnetic</span> field in scale 1:2 500000 have been developed and realized. As a result of processing digital data file AMF the divergences reached 200 ???, have been eliminated. For inclusion in WDMAM-2011 the Russian side the digital model counted on height 1 km on a grid 5?5?? is offered. Anomalous values are designed from normal field VSEGEI of an epoch of 1965. The <span class="hlt">magnetic</span> grid (5x5 km) within the Russian continental shelf compiled in VNIIOkeangeologia was leveled, adjusted and merged with those created in VSEGEI on shore of Russian Federation. Data processing is made by software Geosoft. Russian <span class="hlt">magnetic</span> database in the Arctic Ocean was created as a result of adjusting of all historical and recent <span class="hlt">magnetic</span> data sets, collected several organizations during the period about 40 years. Within the deep part of the Arctic Ocean this information was leveled, adjusted and combined with all available US <span class="hlt">magnetic</span> data sets under cooperative project between and US Naval Research Laboratory. A result of this compilation is presented by grid of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> (5x5 km) that was used in the CAMP-GM project.</p> <div class="credits"> <p class="dwt_author">Livinova, Tamara; Glebovsky, Vladimir</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">109</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999CG.....25..231B"> <span id="translatedtitle">A computer program to estimate the source body <span class="hlt">magnetization</span> direction from <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper, a FORTRAN 77 computer program that estimates the inclination and declination of the <span class="hlt">magnetization</span> of a body causing a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is presented. The program searches for maximum correlation in between the pseudogravity <span class="hlt">anomalies</span> at ranges of body <span class="hlt">magnetization</span> and gravity <span class="hlt">anomalies</span> caused by the same formations. The pseudogravity transformation is performed each time for an array of inclination and declination angles. Test cases demonstrate that the method can be used with confidence. An example of aeromagnetic and gravity <span class="hlt">anomalies</span> from Northern Central Turkey, shows maximum correlation at -22° of declination of body <span class="hlt">magnetization</span>. This result correlates well with the previous research on palaeomagnetic and tectonic work revealing an anticlockwise rotation of Central Turkey.</p> <div class="credits"> <p class="dwt_author">Bilim, F.; Ates, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">110</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.fugroairborne.com/resources/technical_papers/airborne_em/pdfs/EM_MAG.pdf"> <span id="translatedtitle">On the airborne transient EM response of a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Occasionally, airborne <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can have amplitudes as large as 70 000 nT and, for shallow dyke-like bodies, it is possible for the amplitude to vary by more than 70 000 nT over a distance of about 200 m. In such cases, the horizontal spatial gradients can be as large as 700 nT\\/m. Moving an induction coil sensor through a</p> <div class="credits"> <p class="dwt_author">Richard S. Smith</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">111</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www-odp.tamu.edu/publications/123_SR/VOLUME/CHAPTERS/sr123_36.pdf"> <span id="translatedtitle">36. ARGO ABYSSAL PLAIN <span class="hlt">MAGNETIC</span> LINEATIONS REVISITED: IMPLICATIONS FOR THE ONSET OF SEAFLOOR <span class="hlt">SPREADING</span> AND TECTONIC EVOLUTION OF THE EASTERN INDIAN OCEAN1</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Linear <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the Argo Abyssal Plain have been interpreted as having been recorded by seafloor <span class="hlt">spreading</span> during Late Jurassic to Early Cretaceous Chrons M26 through M16. Ocean Drilling Program Leg 123 drilled at Site 765 in the southern Argo Abyssal Plain, near the base of the northwest Australia margin between <span class="hlt">anomalies</span> thought to be M25A and M26. However,</p> <div class="credits"> <p class="dwt_author">William W. Sager; Lawrence G. Fullerton; Richard T. Buffler; David W. Handschumache</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">112</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6779995"> <span id="translatedtitle">Apparatus for detecting a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> contiguous to remote location by SQUID gradiometer and magnetometer systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">A superconducting quantum interference device (SQUID) <span class="hlt">magnetic</span> detection apparatus detects <span class="hlt">magnetic</span> fields, signals, and <span class="hlt">anomalies</span> at remote locations. Two remotely rotatable SQUID gradiometers may be housed in a cryogenic environment to search for and locate unambiguously <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. The SQUID <span class="hlt">magnetic</span> detection apparatus can be used to determine the azimuth of a hydrofracture by first flooding the hydrofracture with a ferrofluid to create an artificial <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> therein.</p> <div class="credits"> <p class="dwt_author">Overton, W.C. Jr.; Steyert, W.A. Jr.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-03-13</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">113</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1991gcai.rept.....G"> <span id="translatedtitle">Evaluation of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> located in Lower Bayou Teche, St. Mary Parish, Louisiana</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This report presents results of testing and assessment of eleven previously recorded <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> located in Lower Bayou Teche, St. Mary Parish, Louisiana. Maintenance dredging of Lower Bayou Teche may impact several of the eight <span class="hlt">anomalies</span> evaluated in this study. Objectives of the study were to conduct detailed surveys and assessments of eight previously located <span class="hlt">anomalies</span>. These were <span class="hlt">Anomalies</span> 8, 13, 24a, 29, 30, 31, 33, and 58. Three orther <span class="hlt">anomalies</span>, <span class="hlt">Anomaly</span> nos. 23, 24b, and 55 were also briefly examined. Methods used during survey included relocation of each <span class="hlt">anomaly</span> with a magnetometer; informal <span class="hlt">magnetic</span> and fathometer survey of each <span class="hlt">anomaly</span> and its vicinity, physical search of the river bottom at each <span class="hlt">anomaly</span> location; use of a metal detector to assess the depth of the <span class="hlt">magnetic</span> source of each <span class="hlt">anomaly</span>; probing of the river bottom to locate buried structures; and limited excavation with a jet probe to document the source, nature, and research potential of each of the eight <span class="hlt">anomalies</span>. Two of the <span class="hlt">anomalies</span>, <span class="hlt">Anomaly</span> nos. 30 and 58 could not be relocated. Four of the <span class="hlt">anomalies</span> apparently are associated with modern debris: <span class="hlt">Anomaly</span> nos. 8, 13, 29, and 31. <span class="hlt">Anomaly</span> no. 33 appears to be an isolated object. Evidence of structure was observed 14 to 15 ft below water surface, however, it occurs below the project impact zone. One archeological site, the <span class="hlt">Anomaly</span> no. 23/24 Complex (Site 16SMY76) was defined. It consists of two wooden barges and some twentieth century bridge remains.</p> <div class="credits"> <p class="dwt_author">Goodwin, R. Christopher; Athens, William P.; Saltus, Allen R., Jr.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">114</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70012476"> <span id="translatedtitle">The moon: Sources of the crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Previously unmapped Apollo 16 subsatellite magnetometer data collected at low altitudes over the lunar near side are presented. Medium-amplitude <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> exist over the Fra Mauro and Cayley Formations (primary and secondary basin ejecta emplaced 3.8 to 4.0 billion years ago) but are nearly absent over the maria and over the craters Copernicus, Kepler, and Reiner and their encircling ejecta mantles. The largest observed <span class="hlt">anomaly</span> (radial component ??? 21 gammas at an altitude of 20 kilometers) is exactly correlated with a conspicuous light-colored deposit on western Oceanus Procellarum known as Reiner ??. Assuming that the Reiner ?? deposit is the source body and estimating its maximum average thickness as 10 meters, a minimum mean <span class="hlt">magnetization</span> level of 5.2 ?? 2.4 ?? 10-2 electromagnetic units per gram, or ??? 500 times the stable <span class="hlt">magnetization</span> component of the most <span class="hlt">magnetic</span> returned sample, is calculated. An age for its emplacement of ??? 2.9 billion years is inferred from photogeologic evidence, implying that <span class="hlt">magnetization</span> of lunar crustal materials must have continued for a period exceeding 1 billion years. Copyright ?? 1979 AAAS.</p> <div class="credits"> <p class="dwt_author">Hood, L. L.; Coleman, Jr. , P. J.; Wilhelms, D. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">115</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE95631480"> <span id="translatedtitle">Mesures du champ magnetique terrestre et de ses <span class="hlt">anomalies</span>. (Measurement of the terrestrial <span class="hlt">magnetic</span> field and its <span class="hlt">anomalies</span>).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">After a presentation of the terrestrial <span class="hlt">magnetic</span> field and its various <span class="hlt">anomalies</span>, the different types of magnetometers commonly used are reviewed with their characteristics and performances: scalar magnetometers (free precession and continuous polarizatio...</p> <div class="credits"> <p class="dwt_author">D. Duret</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">116</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19990103130&hterms=sensitivity+towards+water+hand&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsensitivity%2Btowards%2Bwater%2Bhand"> <span id="translatedtitle">Thermal Sensitivity of MD Hematite: Implication for <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><span class="hlt">Magnetic</span> remanence of crustal rocks can reside in three common rock-forming <span class="hlt">magnetic</span> minerals: magnetite, pyrrhotite, and hematite. Thermoremanent <span class="hlt">magnetization</span> (TRM) of magnetite and pyrrhotite is carried mostly by single domain (SD) grains. The TRM of hematite grains, however, is carried mostly by multidomain (NM) grains. This characteristic is illustrated by TRM acquisition curves for hematite of variable grainsizes. The transition between truly NM behavior and tendency towards SD behavior his been established between hematite grainsizes of 0. 1 and 0.05 mm. Coarse grainsize of lower crustal rocks and the large sensitivity of MD hematite grains to acquire TRM indicates that hematite could be a significant contributor to long-wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">Kletetschka, Gunther; Wasilewski, Peter J.; Taylor, Patrick T.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">117</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54037688"> <span id="translatedtitle">Least-squares Minimization Approaches to Interpret Total <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Due to Spheres</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have developed three different least-squares approaches to determine successively: the depth, <span class="hlt">magnetic</span> angle, and amplitude coefficient of a buried sphere from a total <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. By defining the <span class="hlt">anomaly</span> value at the origin and the nearest zero-<span class="hlt">anomaly</span> distance from the origin on the profile, the problem of depth determination is transformed into the problem of finding a solution of</p> <div class="credits"> <p class="dwt_author">E. M. Abdelrahman; T. M. El-Araby; K. S. Soliman; K. S. Essa; E. R. Abo-Ezz</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">118</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMGP41A0992C"> <span id="translatedtitle">Preliminary interpretation of satellite gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the region of the Philippine Sea Plate</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Philippine Sea, situated in the northwestern Pacific, is one of the largest marginal seas on the Earth. Analysis of the Philippine Sea's intraplate fault tectonic systems and lithosphere's density and <span class="hlt">magnetism</span> structures has a significant contribution to understanding not only the dynamic principles of subduction and convergence zones but also effect of plate subduction on back-arc area. It is also important to have cognizance for structure evolution of the ocean crust, the tension and extending progress of marginal sea basins and the mechanisms of geodynamics. Meanwhile, it can be a significant approach for researching the evolution of the East China Sea and the South China Sea. Using high-precision gravity forwarding method based on spatial domain in spherical coordinate, we have calculated the Bouguer gravity disturbance (BGD) in the Philippine Sea based on the ETOPO1 1 arc-minute topography & bathymetry data and the gravity field model EIGEN-6C. After removing the gravity effect of the sediments and deep abnormal materials, we make spherical cap harmonic analysis of the residual <span class="hlt">anomaly</span> and obtain the topography of Moho and apparent-density's distribution of our study area by alternate iteration inversion method. Then, we calculate the distributions of the study area's <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> based on the Earth <span class="hlt">magnetic</span> model NGDC720, reduce to the pole of the study area's <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> by the equivalent source method based on spherical prism <span class="hlt">magnetic</span> forwarding, inverse the processed <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> with spherical cap harmonic analysis to obtain the topography of Curie surface and the apparent <span class="hlt">magnetic</span> susceptibility distribution. Finally, we divide the Philippine Sea block into tectonic units and derive the faults distributions through the analysis of gravity <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>' linear characteristics. The results show that West Philippine Basin is divided by Central Basin Ridge into two block units, the tectonic trend of the north block is south-east, but there is a trend migration to the south for the south tectonic block which may be related to the southeast rift of the Eurasian plate and the northwest <span class="hlt">spread</span> of the Pacific plate. We find that there are faults of about south-north direction between the north block of West Philippine Basin and Urdaneta Plateau. Moreover, the tectonic is complicated in the south block of West Philippine Basin and there are no apparent tectonic trends. The Shikoku Basin and Parece Vela Basin have lower Bouguer gravity than in West Philippine Basin indicating that the West Philippine Basin has lower thickness crust and becomes thicker from north to south. The density distribution of Philippine plate is not homogeneous, which presents that it is higher in the west plate than the east and shows a low density and low <span class="hlt">magnetism</span> at Central Basin Ridge. And there are many clear and strong striped <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the West Philippine Basin having the direction of NWW-SEE, but in Shikoku Basin and Parece Vela Basin the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is very weak. This study is supported by the National Science Foundation of China (Grant No.: 40730317 and 40774060 ) and International Cooperation Projection in Science and Technology (Grant No.: 2010DFA24580).</p> <div class="credits"> <p class="dwt_author">Chen, C.; Hu, Z.; Du, J.; Wang, Q.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">119</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19870007985&hterms=PangeA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DPangeA"> <span id="translatedtitle">Improving the geological interpretation of <span class="hlt">magnetic</span> and gravity satellite <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Quantitative analysis of the geologic component of observed satellite <span class="hlt">magnetic</span> and gravity fields requires accurate isolation of the geologic component of the observations, theoretically sound and viable inversion techniques, and integration of collateral, constraining geologic and geophysical data. A number of significant contributions were made which make quantitative analysis more accurate. These include procedures for: screening and processing orbital data for lithospheric signals based on signal repeatability and wavelength analysis; producing accurate gridded <span class="hlt">anomaly</span> values at constant elevations from the orbital data by three-dimensional least squares collocation; increasing the stability of equivalent point source inversion and criteria for the selection of the optimum damping parameter; enhancing inversion techniques through an iterative procedure based on the superposition theorem of potential fields; and modeling efficiently regional-scale lithospheric sources of satellite <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. In addition, these techniques were utilized to investigate regional <span class="hlt">anomaly</span> sources of North and South America and India and to provide constraints to continental reconstruction. Since the inception of this research study, eleven papers were presented with associated published abstracts, three theses were completed, four papers were published or accepted for publication, and an additional manuscript was submitted for publication.</p> <div class="credits"> <p class="dwt_author">Hinze, William J.; Braile, Lawrence W.; Vonfrese, Ralph R. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">120</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120011787&hterms=moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmoon"> <span id="translatedtitle">Numerical Simulations on Origin of Galilean Moons' <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Galileo mission detected the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> originated from Galilean moons. These <span class="hlt">anomalies</span> are likely generated in the moons interiors, under the influence of a strong ambient Jovian field. Among various possible generation mechanisms of the <span class="hlt">anomalies</span>, we focus on magneto-convection and dynamos in the interiors via numerical simulation. To mimic the electromagnetic environment of the moons, we introduce in our numerical model an external uniform <span class="hlt">magnetic</span> field B(sub 0) with a fixed orientation but varying field strength. Our results show that a finite B(sub 0) can substantially alter the dynamo processes inside the core. When the ambient field strength B(sub 0) increases to approximately 40% of the field generated by the pure dynamo action, the convective state in the core changes significantly: the convective flow decreases by 80% in magnitude, but the differential rotation becomes stronger in much of the fluid layer, leading to a stronger field generated in the core. The field morphologies inside the core tend to align with the ambient field, while the flow patterns show the symmetry-breaking effect under the influence of B(sub 0). Furthermore, the generated field tends to be temporally more stable.</p> <div class="credits"> <p class="dwt_author">Jiao, LiQuo; Kuang, WeiJia; Ma, ShiZhuang</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_5");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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<img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">121</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N7713587"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map of North America South of 50 Degrees North from Pogo Data.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map produced from Pogo data for North America and adjacent ocean areas is presented. At satellite elevations <span class="hlt">anomalies</span> have wavelengths measured in hundreds of kilometers, and reflect regional structures on a large scale. Prominent feat...</p> <div class="credits"> <p class="dwt_author">M. A. Mayhew</p> <p class="dwt_publisher"></p> <p class="publishDate">1976-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">122</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N7416059"> <span id="translatedtitle">Enhancement of the Equatorial <span class="hlt">Anomaly</span> in the Topside Ionosphere During <span class="hlt">Magnetic</span> Storms.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Alouette ionograms were used to obtain latitudinal variations of the topside electron density through the equatorial <span class="hlt">anomaly</span> region at American longitudes during eight <span class="hlt">magnetic</span> storm events. Seven of the events showed enhancements of the <span class="hlt">anomaly</span> compared ...</p> <div class="credits"> <p class="dwt_author">M. R. Sivaraman R. Raghavarao</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">123</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20030025336&hterms=solid+surface+tension+table&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dsolid%2Bsurface%2Btension%2Btable"> <span id="translatedtitle">Utility of Satellite <span class="hlt">Magnetic</span> Observations for Estimating Near-Surface <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Regional to continental scale <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps are becoming increasingly available from airborne, shipborne, and terrestrial surveys. Satellite data are commonly considered to fill the coverage gaps in regional compilations of these near-surface surveys. For the near-surface Antarctic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map being produced by the Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP), we show that near-surface <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> estimation is greatly enhanced by the joint inversion of the near-surface data with the satellite observations relative to the conventional technique such as minimum curvature. Orsted observations are especially advantageous relative to the Magsat data that have order-of-magnitude greater measurement errors, albeit at much lower orbital altitudes. CHAMP is observing the geomagnetic field with the same measurement accuracy as the Orsted mission, but at the lower orbital altitudes covered by Magsat. Hence, additional significant improvement in predicting near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can result as these CHAMP data are available. Our analysis also suggests that considerable new insights on the <span class="hlt">magnetic</span> properties of the lithosphere may be revealed by a further order-of-magnitude improvement in the accuracy of the magnetometer measurements at minimum orbital altitude.</p> <div class="credits"> <p class="dwt_author">Kim, Hyung Rae; vonFrese, Ralph R. B.; Taylor, Patrick T.; Kim, Jeong Woo; Park, Chan Hong</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">124</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009ExG....40...17I"> <span id="translatedtitle"><span class="hlt">Magnetization</span> structure of Aogashima Island using vector <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> obtained by a helicopter-borne magnetometer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">On Aogashima Island, a volcanic island located in the southernmost part of the Izu Seven Islands Chain, vector <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> were obtained in a helicopter-borne <span class="hlt">magnetic</span> survey. The purpose of this study was to understand the volcanic structure of Aogashima Island in order to mitigate future disasters. Commonly, to obtain the <span class="hlt">magnetic</span> structure of a volcanic island, total intensity <span class="hlt">anomalies</span> (TIA) have been used, even though they have intrinsic errors that have not been evaluated correctly. Because the total intensity <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> (TIA) is not a physical value, it does not satisfy Maxwell's Equations, Laplace's Equation, etc., and so TIA is not suitable for any physical analyses. In addition, it has been conventionally assumed that TIA is the same as the projected total intensity <span class="hlt">anomaly</span> vector (PTA) for analyses of TIA. However, the effect of the intrinsic error (?T=TIA-PTA) on the analysis results has not been taken into account. To avoid such an effect, vector <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> were measured so that a reliable analysis of Aogashima Island <span class="hlt">magnetization</span> could be carried out. In this study, we evaluated the error in TIA and used vector <span class="hlt">anomalies</span> to avoid this erroneous effect, in the process obtaining reliable analysis results for 3D, vector <span class="hlt">magnetization</span> distributions. An area of less than 1 A/m <span class="hlt">magnetization</span> was found in the south-west part of Aogashima Island at the depth of 1-2km. Taking the location of fumarolic activity into consideration, the lower-<span class="hlt">magnetization</span> area was expected to be the source of that fumarolic activity of Aogashima Island.</p> <div class="credits"> <p class="dwt_author">Isezaski, Nobuhiro; Matsuo, Jun</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">125</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014JAG...104..121A"> <span id="translatedtitle">The Paradox of Scale: Reconciling <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> with rock <span class="hlt">magnetic</span> properties for cost-effective mineral exploration</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Targeting <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> is a common practice in the mineral industry. However, it is uncommon for <span class="hlt">anomalies</span> to be reconciled with their causative lithologies after a hole has been drilled. Furthermore, the effects of remanent <span class="hlt">magnetization</span> are seldom considered, even though they are likely to be significant. This study explores how timely rock <span class="hlt">magnetic</span> property measurements coupled with <span class="hlt">magnetic</span> field modelling can be used to explain the <span class="hlt">anomaly</span> whilst drilling is underway, thus saving critical exploration expense.</p> <div class="credits"> <p class="dwt_author">Austin, James R.; Foss, Clive A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">126</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850023274&hterms=magnetic+anomaly+map&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banomaly%2Bmap"> <span id="translatedtitle">MAGSAT satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map over South America</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map was prepared for South America and adjacent marine areas directly from original MAGSAT orbits. Special problems associated with the separation of external field and crustal <span class="hlt">anomalies</span>, and the reduction of data to a common altitude are addressed. External fields are manifested in a long-wavelength ring current effect, a medium-wavelength equatorial electrojet, and short-wavelength noise. The noise is reduced by selecting profiles from quiet periods (Kp or = 3), and the effect of the electrojet is minimized by drawing the data set from dawn profiles only. The ring current is corrected through the use of a standard equation, augmented by further digital band-pass filtering. Profiles thus filtered differ primarily in amplitude due solely to satellite altitude differences. These differences are normalized by an inversion of the profile data onto a grid of equivalent point dipoles, and recalculated at an altitude of 350 km. The low altitudes in the study area cause instability in the inversion, necessitating separate inversions of several sub-areas which are subsequently merged. Crustal <span class="hlt">anomalies</span> reduced-to-the-pole exhibit marked correlations to known tectonic features.</p> <div class="credits"> <p class="dwt_author">Ridgway, J. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">127</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002PhDT........78K"> <span id="translatedtitle">Antarctic lithospheric <span class="hlt">anomalies</span> from Orsted satellite and near-surface <span class="hlt">magnetic</span> observations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We investigate the utility of combining satellite and near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> for enhanced studies of the Antarctic lithosphere. We process <span class="hlt">magnetic</span> data from the Orsted satellite launched in February in 1999 to confirm the veracity of the Antarctic lithospheric <span class="hlt">anomalies</span> mapped by the Magsat mission over twenty years ago. Our analysis reveals that core field model estimates between degree 11 and 13 can contain significant lithospheric components. To extract these components, we use the pseudo <span class="hlt">magnetic</span> effect of a model of Antarctic crustal thickness variations that we obtain by spectrally comparing the terrain gravity to free-air gravity <span class="hlt">anomalies</span>. From the correlation spectrum between the pseudo <span class="hlt">magnetic</span> and degree 11--13 satellite <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, we inversely transform positively correlated satellite wavenumber components for estimates of the <span class="hlt">magnetic</span> crustal thickness effects. By combining these crustal thickness effects with the degree 13 and higher <span class="hlt">anomaly</span> components, we obtain Orsted and Magsat comprehensive <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps of the Antarctic lithosphere at 700 km and 400 km altitudes, respectively. The comprehensive <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> provide important constraints for estimating near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the regional coverage gaps in the Antarctic <span class="hlt">magnetic</span> map being produced by the Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP). We develop an effective procedure for estimating near-surface <span class="hlt">anomaly</span> values in unmapped areas from the joint inversion of satellite and available near-surface data. Relative to the Magsat data, we find that the Orsted data offer significant advantages for this application because of their greatly enhanced measurement accuracy. We extend the joint inversion of satellite and near-surface <span class="hlt">anomalies</span> for modeling the crustal <span class="hlt">magnetic</span> properties of the Maud Rise in the Southwest Indian Ocean off the coast of East Antarctica. We also find that the quantitative crustal model for the Maud Rise can be extrapolated via the satellite <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> to the conjugate Agulhas Plateau off the South African coast for new tectonic perspectives on the Cretaceous breakup of Gondwana.</p> <div class="credits"> <p class="dwt_author">Kim, Hyung Rae</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">128</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850044262&hterms=magnetic+anomaly+map&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banomaly%2Bmap"> <span id="translatedtitle">Comparison between the recent U.S. composite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map and Magsat <span class="hlt">anomaly</span> data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The present investigation is concerned with a comparison of Magsat data with a Composite <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map (CMAM) of the conterminous U.S. reported by Zietz (1982). The investigation was initiated to test the validity of the satellite measurements, and to provide insights into error or problems in either data set. It is found that upward continuation of the digital CMAM data is not in qualitative agreement with the Magsat map. However, if a least squares fit polynomial surface is taken out prior to upward continuation, there is improved quantitative agreement between a residual CMAM and Magsat. Causes for the remaining differences between the residual, upward continued CMAM and the Magsat map are also considered.</p> <div class="credits"> <p class="dwt_author">Schnetzler, C. C.; Taylor, P. T.; Langel, R. A.; Hinze, W. J.; Phillips, J. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">129</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40281260"> <span id="translatedtitle">Determination of vertical <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and equivalent layer for the European region from the Magsat measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Two procedures are developed and discussed: the determination of the vertical <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> derived from the Magsat data and the determination of <span class="hlt">magnetic</span> moment of the Earth's surface layer derived from the vertical <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. The selected and corrected Magsat data are interpolated for a sphere of radius 6771 km (elevation 400 km) for the interval of 30°–60°N in latitude,</p> <div class="credits"> <p class="dwt_author">K. I. Kis; G. Wittmann</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">130</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009EGUGA..11.4082A"> <span id="translatedtitle">Edge detection of <span class="hlt">magnetic</span> body using horizontal gradient of pseudogravity <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Potential field methods are used extensively in mineral exploration. These methods also are used as reconnaissance method in oil and gas exploration. In Contrast with gravity <span class="hlt">anomaly</span> the <span class="hlt">magnetic</span> surveying produces dipolar <span class="hlt">anomaly</span> which is caused complicated interpretation rather than gravity <span class="hlt">anomaly</span>. The observation <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in each location other than <span class="hlt">magnetic</span> poles has displacement rather than causative body. Several methods are used to overcome to this problem such as reduction to the pole (RTP) that an asymmetric <span class="hlt">anomaly</span> is converted to symmetrical <span class="hlt">anomaly</span>. Boundary analysis is another method to distinguish causative <span class="hlt">magnetic</span> body from observed <span class="hlt">magnetic</span> data directly. One of the applicable methods in boundary detection of local scale <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is total gradient of pseudogravity <span class="hlt">anomaly</span>. In this method, pseudogravity <span class="hlt">anomaly</span> is calculated in the first step. Pseudogravity converts the <span class="hlt">magnetic</span> field into gravity field that would be observed if the <span class="hlt">magnetization</span> distribution were to be replaced with an identical density distribution. This filter is a linear filter that is created in the frequency domain. Poisson's relationship between <span class="hlt">magnetic</span> and gravity potential can be used for <span class="hlt">magnetic</span> and gravity <span class="hlt">anomaly</span> transformation to each other. Pseudogravity transformation is done in 3 steps (1) Fourier transform of <span class="hlt">magnetic</span> data to frequency domain. (2) Multiplying the result of step (1) on to pseudogravity filter expression. (3) Inverse Fourier transform to space domain. It is a useful technique for the interpretation of major magneto- tectonic provinces as it simplifies <span class="hlt">anomaly</span> patterns and focuses on large scale features rather than local details. After this process the horizontal gradient of calculated pseudogravity <span class="hlt">anomaly</span> is computed and mapped in surveying scale. In this image maximum value of total horizontal gradient determines <span class="hlt">magnetic</span> body edge. In this work we applied this method to synthetic <span class="hlt">magnetic</span> data from prismatic model and also in <span class="hlt">magnetic</span> data from Gol-Gohar mining area from Iran. This area is one of the iron ore in Iran and located in 1:250000 map in Neyriz geological block. For implementation the described method to studied area observation <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> was transformed to pseudogravity <span class="hlt">anomaly</span> at the first step. Then horizontal gradient of this <span class="hlt">anomaly</span> was calculated and mapped. Maximum value of horizontal gradient of psedogravity as form of two bands located in <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> trend direction. Field observations show an iron vein with 30m width that using described technique as a boundary detection method, confirms this feature. Keywords: <span class="hlt">Magnetization</span>, Edge detection, Reduction to the pole, pseudogravity, Poisson's relationship, Horizontal gradient, Gol-Gohar.</p> <div class="credits"> <p class="dwt_author">Alamdar, K.; Ansari, A. H.; Ghorbani, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">131</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EGUGA..12.6078P"> <span id="translatedtitle">Magnetotelluric <span class="hlt">anomalies</span>, computed over models having high <span class="hlt">magnetic</span> permeability bodies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In magnetotellurics it is assumed that the relative <span class="hlt">magnetic</span> permeability is 1. We carried out systematic magnetotelluric numerical modelling studies to analyse the magnetotelluric effect due to a hypothetically high-permeability body in the subsurface, e.g. due to a thin (a few hundred meter thick) layer in state of second-order <span class="hlt">magnetic</span> phase transition at the Curie depth (Kiss et al, GRL, 2005). In one-dimensional case, we have demonstrated that a thin, highly <span class="hlt">magnetized</span> layer produces the same size of a magnetotelluric <span class="hlt">anomaly</span> as a similarly thin high-conductivity layer, but with the opposite sign. Its signatures are as follows. 1) extremely thick and extremely high-resistivity layers as results of magnetotelluric inversion, and 2) consistent magnetotelluric and geomagnetic depth estimations for the top of the highly <span class="hlt">magnetized</span> thin layer. Various two-dimensional cases (both in E and H polarisations) give further insights into this phenomenon. If the enhancement of the <span class="hlt">magnetic</span> permeability is exceptionally high, the effect may really distort the conventional magnetotelluric results. Such indications have already been observed in some magnetotelluric field curves in Hungary. OTKA Hungarian National Research Fund, Project No 68475</p> <div class="credits"> <p class="dwt_author">Prácser, Ern?; Kiss, János; Ádám, Antal; Szarka, László</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">132</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/22218401"> <span id="translatedtitle">Current disruption and its <span class="hlt">spreading</span> in collisionless <span class="hlt">magnetic</span> reconnection</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Recent <span class="hlt">magnetic</span> reconnection experiments (MRX) [Dorfman et al., Geophys. Res. Lett. 40, 233 (2013)] have disclosed current disruption in the absence of an externally imposed guide field. During current disruption in MRX, both the current density and the total observed out-of-reconnection-plane current drop simultaneous with a rise in out-of-reconnection-plane electric field. Here, we show that current disruption is an intrinsic property of the dynamic formation of an X-point configuration of <span class="hlt">magnetic</span> field in <span class="hlt">magnetic</span> reconnection, independent of the model used for plasma description and of the dimensionality (2D or 3D) of reconnection. An analytic expression for the current drop is derived from Ampere's Law. Its predictions are verified by 2D and 3D electron-magnetohydrodynamic (EMHD) simulations. Three dimensional EMHD simulations show that the current disruption due to localized <span class="hlt">magnetic</span> reconnection <span class="hlt">spreads</span> along the direction of the electron drift velocity with a speed which depends on the wave number of the perturbation. The implications of these results for MRX are discussed.</p> <div class="credits"> <p class="dwt_author">Jain, Neeraj; Büchner, Jörg [Max-Planck/Princeton Center for Plasma Physics, Max Planck Institute for Solar System Research, 37191 Katlenburg-Lindau (Germany)] [Max-Planck/Princeton Center for Plasma Physics, Max Planck Institute for Solar System Research, 37191 Katlenburg-Lindau (Germany); Dorfman, Seth [University of California Los Angeles, Los Angeles, California 90095 (United States)] [University of California Los Angeles, Los Angeles, California 90095 (United States); Ji, Hantao [Max-Planck/Princeton Center for Plasma Physics, Deparment of Astrophysica Sciences and Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08540 (United States)] [Max-Planck/Princeton Center for Plasma Physics, Deparment of Astrophysica Sciences and Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08540 (United States); Surjalal Sharma, A. [Department of Astronomy, University of Maryland, College Park, Maryland 20742 (United States)] [Department of Astronomy, University of Maryland, College Park, Maryland 20742 (United States)</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">133</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhPl...20k2101J"> <span id="translatedtitle">Current disruption and its <span class="hlt">spreading</span> in collisionless <span class="hlt">magnetic</span> reconnection</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Recent <span class="hlt">magnetic</span> reconnection experiments (MRX) [Dorfman et al., Geophys. Res. Lett. 40, 233 (2013)] have disclosed current disruption in the absence of an externally imposed guide field. During current disruption in MRX, both the current density and the total observed out-of-reconnection-plane current drop simultaneous with a rise in out-of-reconnection-plane electric field. Here, we show that current disruption is an intrinsic property of the dynamic formation of an X-point configuration of <span class="hlt">magnetic</span> field in <span class="hlt">magnetic</span> reconnection, independent of the model used for plasma description and of the dimensionality (2D or 3D) of reconnection. An analytic expression for the current drop is derived from Ampere's Law. Its predictions are verified by 2D and 3D electron-magnetohydrodynamic (EMHD) simulations. Three dimensional EMHD simulations show that the current disruption due to localized <span class="hlt">magnetic</span> reconnection <span class="hlt">spreads</span> along the direction of the electron drift velocity with a speed which depends on the wave number of the perturbation. The implications of these results for MRX are discussed.</p> <div class="credits"> <p class="dwt_author">Jain, Neeraj; Büchner, Jörg; Dorfman, Seth; Ji, Hantao; Surjalal Sharma, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">134</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42001547"> <span id="translatedtitle">Initial mapping and interpretation of lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> using Lunar Prospector magnetometer data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Maps of relatively strong crustal <span class="hlt">magnetic</span> field <span class="hlt">anomalies</span> detected at low altitudes with the magnetometer instrument on Lunar Prospector are presented. On the lunar nearside, relatively strong <span class="hlt">anomalies</span> are mapped over the Reiner Gamma Formation on western Oceanus Procellarum and over the Rima Sirsalis rille on the southwestern border of Oceanus Procellarum. The main Rima Sirsalis <span class="hlt">anomaly</span> does not correlate</p> <div class="credits"> <p class="dwt_author">L. L. Hood; A. Zakharian; J. Halekas; D. L. Mitchell; R. P. Lin; M. H. Acuña; A. B. Binder</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">135</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP11A..07F"> <span id="translatedtitle">Absolute <span class="hlt">Magnetization</span> Distribution on Back-arc <span class="hlt">Spreading</span> Axis Hosting Hydrothermal Vents; Insight from Shinkai 6500 <span class="hlt">Magnetic</span> Survey</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Near-bottom <span class="hlt">magnetic</span> profiling using submersible, deep-tow, Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV) make possible to conduct high-resolution surveys and depict detailed <span class="hlt">magnetic</span> features reflecting, for instance, the presence of fresh lavas or hydrothermal alteration, or geomagnetic paleo-intensity variations. We conducted near-bottom three component <span class="hlt">magnetic</span> measurements onboard submersible Shinkai 6500 in the Southern Mariana Trough, where five active hydrothermal vent fields (Snail, Yamanaka, Archean, Pica, and Urashima sites) have been found in both on- and off-axis areas of the active back-arc <span class="hlt">spreading</span> center, to detect signals from hydrothermally altered rock and to distinguish old and new submarine lava flows. Fourteen dives were carried out at an altitude of 1-40 m during the R/V Yokosuka YK10-10 and YK10-11 cruises in 2010. We carefully corrected the effect of the induced and permanent <span class="hlt">magnetizations</span> of the submersible by applying the correction method for the shipboard three-component magnetometer measurement modified for deep-sea measurement, and subtracted the IGRF values from the corrected data to obtain geomagnetic vector <span class="hlt">anomalies</span> along the dive tracks. We then calculated the synthetic <span class="hlt">magnetic</span> vector field produced by seafloor, assumed to be uniformly <span class="hlt">magnetized</span>, using three dimensional forward modeling. Finally, values of the absolute <span class="hlt">magnetizations</span> were estimated by using a linear transfer function in the Fourier domain from the observed and synthetic <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. The distribution of estimated absolute <span class="hlt">magnetization</span> generally shows low values around the five hydrothermal vent sites. This result is consistent with the equivalent <span class="hlt">magnetization</span> distribution obtained from previous AUV survey data. The areas of low <span class="hlt">magnetization</span> are also consistent with hydrothermal deposits identified in video records. These results suggest that low <span class="hlt">magnetic</span> signals are due to hydrothermal alteration zones where host rocks are demagnetized by hydrothermal circulation. The low <span class="hlt">magnetization</span> zones around the off-axis vent sites are about ten times wider than those surrounding the on-axis sites, possibly reflecting the longer duration of hydrothermal circulation at these sites. Another interesting result is that the absolute <span class="hlt">magnetization</span> shows extremely high intensities (>80 A/m) at the neo volcanic zones (NVZ) and relatively low intensities (<10 A/m) two to five kilometers away from the NVZ. These variations are quite consistent with those of the Natural Remanent <span class="hlt">Magnetization</span> measured on basalt samples, suggesting that the low-temperature oxidation of host rock due to the reaction with seawater has completed within a few kilometers distance from the <span class="hlt">spreading</span> axis. We conclude that the <span class="hlt">magnetization</span> of the uppermost oceanic crust decreases with age due to the combination of the both hydrothermal rapid alteration and the low-temperature gradual alteration processes.</p> <div class="credits"> <p class="dwt_author">Fujii, M.; Okino, K.; Honsho, C.; Mochizuki, N.; Szitkar, F.; Dyment, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">136</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007SPIE.6553E..14K"> <span id="translatedtitle">Underwater <span class="hlt">magnetic</span> gradiometer for <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> detection, localization, and tracking</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">GE Security and the Naval Surface Warfare Center, Panama City (NSWC-PC) have collaborated to develop a <span class="hlt">magnetic</span> gradiometer, called the Real-time Tracking Gradiometer or RTG that is mounted inside an unmanned underwater vehicle (UUV). The RTG is part of a buried mine hunting platform being developed by the United States Navy. The RTG has been successfully used to make test runs on mine-like targets buried off the coast of Florida. We will present a general description of the system and latest results describing system performance. This system can be also potentially used for other applications including those in the area of Homeland Security.</p> <div class="credits"> <p class="dwt_author">Kumar, S.; Sulzberger, G.; Bono, J.; Skvoretz, D.; Allen, G. I.; Clem, T. R.; Ebbert, M.; Bennett, S. L.; Ostrom, R. K.; Tzouris, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">137</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17732627"> <span id="translatedtitle">Sea-Floor <span class="hlt">Spreading</span> near the Galapagos.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Seismicity, volcanism, and a linear pattern of very large <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> that show symmetry about a broad negative <span class="hlt">anomaly</span> suggest that a type of sea-floor <span class="hlt">spreading</span> occurs near the Galapagos Islands in the east-equatorial Pacific. This <span class="hlt">spreading</span> results from the tensile stresses generated by different <span class="hlt">spreading</span> directions of two adjacent segments of the East Pacific Rise, and it is suggested that the area be called the Galapagos Rift Zone. PMID:17732627</p> <div class="credits"> <p class="dwt_author">Herron, E M; Heirtzler, J R</p> <p class="dwt_publisher"></p> <p class="publishDate">1967-11-10</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">138</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JAESc..77...12G"> <span id="translatedtitle">Distribution of the crustal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and geological structure in Xinjiang, China</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Based on the high-order crustal <span class="hlt">magnetic</span> field model NGDC-720-V3, we investigate the distribution of crustal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, the decay characteristics of the <span class="hlt">anomaly</span>, and the relationship between the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and geological structure in Xinjiang, China. Topography of the <span class="hlt">magnetic</span> layer basement is studied through Curie isothermal surface using the power spectrum method. It is found that south Tarim Basin, Junggar Basin, and Turpan-Hami Basin have strong positive <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, whereas west Kunlun Mountain, Altun Mountain, Tianshan Mountain, and Altai Mountain have weak or negative <span class="hlt">anomaly</span>. The <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> well reflects the regional tectonic structure, i.e., three alternating mountains intervened by two basins. The <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> on the ground surface in Tarim Basin is well corresponding to the mafic dykes. The decay of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> with altitude indicates that Xinjiang is a large massif composed of several <span class="hlt">magnetic</span> blocks with different sizes in different directions. The Curie surface presents a feature of being shallow under mountains whereas being deep under basins, roughly having an anti-mirror correspondence with the Moho depth.</p> <div class="credits"> <p class="dwt_author">Gao, Guoming; Kang, Guofa; Bai, Chunhua; Li, Guangquan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">139</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830009648&hterms=Anomalies+sun&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DAnomalies%2Bnear%2Bsun"> <span id="translatedtitle">On long-wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over Indian region</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A data set composed of vector <span class="hlt">magnetic</span> measurements obtained by MAGSAT and very accurate altitude determinations made using Sun sensors and star cameras was used to obtain data for very quiet days over the Indian region at 10 S to 40 N and 60 E to 110 E in an effort to determine the validity of quantitative estimates made from aeromagnetic data obtained by removing the core field. To further account for the external effects, the ring current contributions estimated using both X and Z variations were subtracted from the observed values. Before this, the core contribution was eliminated through a spherical harmonic expansion with terms up to N=13. Analysis of the residual measurements using Fast Fourier techniques indicates that the <span class="hlt">anomalies</span> contain substantial power for wavelengths of about 1500 kms. Because the ring current effect has a spatial structure of this dimension over India, efforts are being made to exactly eliminate these two interfering effects from the data.</p> <div class="credits"> <p class="dwt_author">Srinivasan, S.; Carlo, L.; Rastogi, R. G.; Singh, B. P. (principal investigators)</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">140</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFMGP31A0074S"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map of the Weaubleau Quadrangle, South Central Missouri</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the August of 2001 and May of 2005 <span class="hlt">magnetic</span> surveys were conducted throughout the Weaubleau (pronounced Wah-blow), MO quadrangle (located approximately 90 km north of Springfield). The <span class="hlt">magnetic</span> data were collected using a Geometrics G-856 Proton Precession Magnetometer with position and elevation data collected by a Trimble GPS Pathfinder Pro XRS unit. One hundred and ten stations were occupied in the 2001 survey with seventy-three stations occupied or, in some cases, reoccupied in 2005. These data are reduced and presented as a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map of the Weaubleau quadrangle. This area has proven interesting because of an intense deformation of Mississippian and older formations whereas Pennsylvanian formations, which unconformably overly these, are largely undeformed. The cause of this deformation has alternately been attributed to meteorite impact, cryptocrystalline volcanic disturbance or widespread horizontal compression. We look for features having circular symmetry which would support an impact origin, or having a preferred linear orientation which would support a compression origin.</p> <div class="credits"> <p class="dwt_author">Shoberg, T.; Stoddard, P. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_6");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">141</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/39650737"> <span id="translatedtitle">Least-squares Minimization Approaches to Interpret Total <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Due to Spheres</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have developed three different least-squares approaches to determine successively: the depth, <span class="hlt">magnetic</span> angle, and amplitude\\u000a coefficient of a buried sphere from a total <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. By defining the <span class="hlt">anomaly</span> value at the origin and the nearest\\u000a zero-<span class="hlt">anomaly</span> distance from the origin on the profile, the problem of depth determination is transformed into the problem of\\u000a finding a solution of</p> <div class="credits"> <p class="dwt_author">E. M. Abdelrahman; T. M. El-Araby; K. S. Soliman; K. S. Essa; E. R. Abo-Ezz</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">142</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.P13B1759L"> <span id="translatedtitle">Optical effects of space weathering in lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> regions based on CE-1 observations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The discovery of mini-magnetospheres above the lunar surface suggests that <span class="hlt">magnetic</span> shielding could have led to anomalous space weathering (little darkening with limited reddening) in <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> regions. Using spectral data from Chang'E 1 Imaging Interferometer (IIM) and data from Lunar Prospector's magnetometer, we instigate the relationship between lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and the optical effects in those areas in association with space weathering. The IIM onboard China's Chang'E 1 (CE-1) spacecraft is a Fourier transform Sagnac imaging spectrometer operating in the visible to near infrared (0.48-0.96 ?m) spectral range, with 32 channels at spectral intervals of 325.5 cm-1. We selected four regions with crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> to study their albedo properties: three lunar swirls (Gerasimovich, Mare Marginis, and Reiner Gamma) and the area antipodal to Herzsprung. We found that all three of the anomalous albedo areas are associated with <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, however, no anomalous albedo feature is found in the last <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> area. In addition, we also studied the correlation between <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> strength and albedo <span class="hlt">anomaly</span> on a global scale. Our initial analysis suggests an overall tread of less darkening with increased <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>.</p> <div class="credits"> <p class="dwt_author">Li, H.; Wang, X.; Cui, J.; Fu, X.; Zhang, G.; Yao, M.; Liu, B.; Liu, J.; Li, C.; Ouyang, Z.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">143</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUFMGP31A0832V"> <span id="translatedtitle">Estimating Antarctic near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from Oersted and CHAMP satellite magnetometer observations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Significant improvement in predicting near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can result from the highly accurate <span class="hlt">magnetic</span> observations of the CHAMP satellite that is orbiting at about 400 km altitude. In general, regional <span class="hlt">magnetic</span> signals of the crust are strongly masked by the core field and its secular variations due to wavelength coupling in the spherical harmonic representation and thus are difficult to isolate in the satellite measurements. However, efforts to isolate the regional lithospheric from core field components can exploit the correlations between the CHAMP <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and the pseudo <span class="hlt">magnetic</span> effects inferred from gravity-derived crustal thickness variations. In addition, we can use spectral correlation theory to filter the static lithospheric field components from the dynamic external field effects. Employing these procedures, we processed the CHAMP <span class="hlt">magnetic</span> observations for an improved <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map of the Antarctic crust. Relative to the much higher altitude Oersted and noisier Magsat observations, CHAMP <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> at 400 km altitude reveal new details on the effects of intra-crustal <span class="hlt">magnetic</span> features and crustal thickness variations of the Antarctic. Moreover, these results greatly facilitate predicting <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the regional coverage gaps of the ADMAP compilation of Antarctic <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from shipborne, airborne and ground surveys. Our analysis suggests that considerable new insights on the <span class="hlt">magnetic</span> properties of the lithosphere may be revealed by a further order-of-magnitude improvement in the accuracy of the magnetometer measurements at minimum orbital altitude.</p> <div class="credits"> <p class="dwt_author">von Frese, R. R.; Kim, H.; Gaya-Pique, L. R.; Taylor, P. T.; Golynsky, A. V.; Kim, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">144</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040171248&hterms=magnetometer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnetometer"> <span id="translatedtitle">Estimating Antarctic Near-Surface <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> from Oersted and CHAMP Satellite Magnetometer Observations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Significant improvement in predicting near-surface <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can result from the highly accurate <span class="hlt">magnetic</span> observations of the CHAMP satellite that is orbiting at about 400 km altitude. In general, regional <span class="hlt">magnetic</span> signals of the crust are strongly masked by the core field and its secular variations due to wavelength coupling in the spherical harmonic representation and thus are difficult to isolate in the satellite measurements. However, efforts to isolate the regional lithospheric from core field components can exploit the correlations between the CHAMP <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and the pseudo <span class="hlt">magnetic</span> effects inferred from gravity-derived crustal thickness variations. In addition, we can use spectral correlation theory to filter the static lithospheric field components from the dynamic external field effects. Employing these procedures, we processed the CHAMP <span class="hlt">magnetic</span> conservations for an improved <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map of the Antarctic crust. Relative to the much higher altitude Oersted and noisier Magsat observations, CHAMP <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> at 400 km altitude reveal new details on the effects of intra-crustal <span class="hlt">magnetic</span> features and crustal thickness variations of the Antarctic. Moreover, these results greatly facilitate predicting <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the regional coverage gaps of the ADMAP compilation of Antarctic <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from shipborne, airborne and ground surveys. Our analysis suggests that considerable new insights on the <span class="hlt">magnetic</span> properties of the lithosphere may be revealed by a further order-of-magnitude improvement in the accuracy of the magnetometer.</p> <div class="credits"> <p class="dwt_author">vonFrese, Ralph R. B.; Kim, Hyung Rae; Gaya-Pique, Luis R.; Taylor, Patrick T.; Golynsky, Alexander V.; Kim, Jeong Woo</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">145</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003JGRB..108.2116C"> <span id="translatedtitle">The Gakkel Ridge: Bathymetry, gravity <span class="hlt">anomalies</span>, and crustal accretion at extremely slow <span class="hlt">spreading</span> rates</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Gakkel Ridge in the Arctic Ocean is the slowest <span class="hlt">spreading</span> portion of the global mid-ocean ridge system. Total <span class="hlt">spreading</span> rates range from 12.7 mm/yr near Greenland to 6.0 mm/yr where the ridge disappears beneath the Laptev Shelf. Swath bathymetry and gravity data for an 850 km long section of the Gakkel Ridge from 5°E to 97°E were obtained from the U.S. Navy submarine USS Hawkbill. The ridge axis is very deep, generally 4700-5300 m, within a well-developed rift valley. The topography is primarily tectonic in origin, characterized by linear rift-parallel ridges and fault-bounded troughs with up to 2 km of relief. Evidence of extrusive volcanic activity is limited and confined to specific locations. East of 32°E, isolated discrete volcanoes are observed at 25-95 km intervals along the axis. Abundant small-scale volcanism characteristic of the Mid-Atlantic Ridge (MAR) is absent. It appears that the amount of melt generated is insufficient to maintain a continuous magmatic <span class="hlt">spreading</span> axis. Instead, melt is erupted on the seafloor at a set of distinct locations where multiple eruptions have built up central volcanoes and covered adjacent areas with low relief lava flows. Between 5°E and 32°E, almost no volcanic activity is observed except near 19°E. The ridge axis shoals rapidly by 1500 m over a 30 km wide area at 19°E, which coincides with a highstanding axis-perpendicular bathymetric high. Bathymetry and side scan data show the presence of numerous small volcanic features and flow fronts in the axial valley on the upper portions of the 19°E along-axis high. Gravity data imply up to 3 km of crustal thickening under the 19°E axis-perpendicular ridge. The 19°E magmatic center may result from interaction of the ridge with a passively imbedded mantle inhomogeneity. Away from 19°E, the crust appears thin and patchy and may consist of basalt directly over peridotite. The ridge axis is continuous with no transform offsets. However, sections of the ridge have distinctly different linear trends. Changes in ridge trend at 32°E and 63°E are associated with a set of bathymetric features that are very similar to each other and to inside/outside corner complexes observed at the MAR including highstanding "inside corner" ridges, which gravity data show to be of tectonic rather than magmatic origin.</p> <div class="credits"> <p class="dwt_author">Cochran, James R.; Kurras, Gregory J.; Edwards, Margo H.; Coakley, Bernard J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">146</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T43D2704F"> <span id="translatedtitle"><span class="hlt">Magnetic</span> Structure of Backarc <span class="hlt">Spreading</span> Axis with Hydrothermal Vents; the Southern Mariana Trough</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Seafloor hydrothermal systems are important in relation to global heat and chemical fluxes as well as habitat of microbial communities. The substantial variation of hydrothermal systems in various tectonic settings has important implications for the <span class="hlt">magnetic</span> structure of oceanic crust. It has been very difficult to detect the geophysical signature of hydrothermal systems from sea-surface data because the small scale of hydrothermal systems is below the limit of resolution. The advance of near-bottom survey methods using a submersible, deep-tow, ROV and AUV has made possible high-resolution geophysical mapping around hydrothermal areas. Near-bottom <span class="hlt">magnetic</span> surveys can provide direct information on the <span class="hlt">magnetization</span> of the shallower oceanic crust, implying hydrothermal alteration both in active and fossil vent sites. Near-bottom three component <span class="hlt">magnetic</span> measurements on submersible Shinkai 6500 were carried out at hydrothermal fields in the Southern Mariana Trough, a slow <span class="hlt">spreading</span> backarc basin. Fourteen dive surveys were conducted during cruises YK11-10 and YK10-11. We investigated the <span class="hlt">magnetic</span> structure of four hydrothermal systems located at on- and off-axis to clarify how the geophysical and geological setting controls the fluid circulation at small scale. Recent researches at slow <span class="hlt">spreading</span> ridges showed a relationship between crustal <span class="hlt">magnetic</span> structure and host rock around hydrothermal vents (e.g. Tivey and Dyment, 2010), but no observation at backarc <span class="hlt">spreading</span> axis has been reported so far. We carefully corrected the effects of induced and permanent <span class="hlt">magnetizations</span> of the submersible by applying the method of Isezaki [1986] with dumped least-square method (Honsho et al., 2009). After subtracting the IGRF from the corrected observed data, we obtained geomagnetic vector <span class="hlt">anomalies</span> in geographical coordinate. For three transects of the axis, we applied three methods; 2D inversion technique (Parker and Huestis, 1972), 2D forward modeling technique (Honsho et al, 2009) and 2D direct inversion technique (Hussenoeder et al., 1995). Transect 1 (T1) and transect 2 (T2) are parallel and very closely located, crossing the neo-volcanic zone near an on-axis hydrothermal site (Snail Site) at different altitude, 2m and 30m. Transect 3 (T3) also crosses a large on-axis volcanic mound on which another hydrothermal site (Yamanaka Site) is located. The equivalent <span class="hlt">magnetization</span> calculated on T1 and T2 are similar although their resolutions are different. The one along T3 shows high values around the large volcanic mound and an area of low <span class="hlt">magnetization</span> near a hydrothermal field recognized from high-resolution bathymetry (Yoshikawa et al., 2012). A similar reduction of <span class="hlt">magnetization</span> above hydrothermal fields was also reported in basalt-hosted sites along the Mid Atlantic Ridge. The detailed bathymetry (2m grid) collected by AUV Urashima in the study area allows us to investigate the effect of three dimensional structure. We estimate <span class="hlt">magnetization</span> using a new technique based on 3D forward modeling (Szitkar et al, this meeting). A preliminary result shows a similar but more detailed <span class="hlt">magnetic</span> structure around the Yamanaka Site compared to results of the 2D methods.</p> <div class="credits"> <p class="dwt_author">Fujii, M.; Okino, K.; Mochizuki, N.; Honsho, C.; Szitkar, F.; Dyment, J.; Nakamura, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">147</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T43B2661Z"> <span id="translatedtitle">The characteristics of <span class="hlt">Magnetic</span> <span class="hlt">anomalies</span> in the northern South China Sea and their Implications for pre-Cenozoic tectonic</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We investigated the <span class="hlt">magnetic</span> signature of the northern SCS based on the latest shipboard <span class="hlt">magnetic</span> data. By the analysis of plane characteristics and comprehensive inversion on profiles, we discussed the HMAB, the MQZ and the HVL in the lower crust, the relationship between the ancient subduction zone in late-Mesozoic and the following continental margin rifting, and We make the following conclusions. (1) The HMAB which coincides with the Dongsha uplift, together with the volcanic belt in the coastal area of Zhejiang and Fujian Provinces, are two volcanic arcs separated by the NW-oriented fault F10 during the subduction of the paleo-Pacific Plate. The cause of the high <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is big differences of the upper crust <span class="hlt">magnetic</span> materials between the two sides of the boundary faults. F10 controlled the following sudduction, might be a transform fault between the paleo-Tethys regime and the paleo-Pacific regime. (2) F2 was the southern margin of the Dongsha Uplift. The <span class="hlt">magnetic</span> difference between the two sides of the F2 is most evident in the northern margin of the SCS. F2 might already exist before the marginal rifting which may be related to magmatic underplating, and defined the northern boundary of the underplating. The fault F3 is a middle continental slope fault. Remarkable lower crust thinning occurs south to F3. The Curie point depth and the Moho intersect near F3. F3 is a weak zone before the crustal extension and thinning, and deep thermal state is different on its two sides, which may reveal the location of the Late Mesozoic subduction. (3) The MQZ can be divided into two parts. The landward part is the low-amplitude negative <span class="hlt">anomaly</span> zone while the seaward part is the low-amplitude positive <span class="hlt">anomaly</span> zone. The two parts are separated by F3. The low-amplitude negative <span class="hlt">anomaly</span> coincides with the thicker HVL, and decreasing susceptibility and density of the upper crust. Meanwhile, in the southern part, the thickness of the HVL decreases to zero sharply. The low-amplitude positive <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> of this region is caused by the small-scale basaltic <span class="hlt">magnetic</span> body formed during the initial oblique seafloor <span class="hlt">spreading</span>, and thus indicative of the existence of an old oceanic crust. RTP <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the northern South China Sea</p> <div class="credits"> <p class="dwt_author">Zhaocai, W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">148</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP41C1130V"> <span id="translatedtitle">Paleomagnetic and rock <span class="hlt">magnetic</span> characterization of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the Central Iberian Arc (Iberian Peninsula)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Central Iberian Arc is one of the four oroclines delineated by the European Variscan Belt. It is located in NW and Central Iberia and characterized by a conspicuous <span class="hlt">magnetic</span> response. The most intense <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> within this arc is the so called Eastern Galicia <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (EGMA; Aller et al., 1994), located in the northern part of Spain and associated to the Lugo-Sanabria dome, an extensional structure in the inner part of arc. The aeromagnetic map of the Iberian Peninsula (Ardizone et al., 1989; Miranda et al., 1989) shows that the EGMA continues to Central Spain and turns back to the Atlantic Ocean, as a broad positive <span class="hlt">anomaly</span>, delineating a tight fold at the core of the Central Iberian Arc. The source of the EGMA seems to be magnetite-bearing migmatites and inhomogeneous granites formed during an extensive late Carboniferous thermal event triggered by Variscan crustal thickening. These rocks were modeled as a lens-shaped body up to 12 km thick with <span class="hlt">magnetic</span> susceptibility values between 0.02and 0.03 SI units, that underlie the whole dome extension and continues toward the west of it (Ayarza and Martínez Catalán, 2007). However, this body crops out only in the deepest and northernmost part of the dome, in the Xistral Tectonic Window, and there, only its upper part is accessible. Migmatites and granitoids are abundant along the rest of the <span class="hlt">anomaly</span>, but their <span class="hlt">magnetic</span> susceptibility is low. Thus, the source of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> should be buried there and its nature is unknown. Paleomagnetic and rock <span class="hlt">magnetic</span> studies in the outcropping rocks responsible for the EGMA have been carried out, adding new constraints to the origin of this <span class="hlt">anomaly</span>. Rock <span class="hlt">magnetic</span> analysis as progressive acquisition of IRM, hysteresis loops, thermomagnetic experiments and X-ray indicate that the ferromagnetic fraction is dominated by multidomain magnetite and titanohematite. It is remarkable the unusual high anisotropy of <span class="hlt">magnetic</span> susceptibility of these rocks, showing degree of anisotropy values 1.2<P<3. The observed <span class="hlt">magnetic</span> fabric shows Variscan affinity, related to an extensional ductile detachment that bounds the Lugo-Sanabria dome to the west. The paleomagnetic analysis consisting in thermal and alternating field demagnetization allows isolating a stable paleomagnetic component with high coercivity and maximum unblocking temperatures of about 630°C, that systematically shows reversed polarity. This component has been interpreted as a remagnetization because its mean direction match those of the Iberian Peninsula after anticlockwise rotation related to the opening of the Bay of Biscay during the Early Cretaceous. All these data must be included in the models in order to place new constraints on the origin, position, and shape of the source and to asses whether all the broad <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> at the core of the Central Iberian Arc has the same origin as the EGMA, or a deeper source contributes to it and to the rest of the <span class="hlt">anomaly</span>.</p> <div class="credits"> <p class="dwt_author">Villalain, J.; Ayarza, P.; Martinez-Catalan, J. R.; Álvarez-Lobato, F.; Gómez-Barreiro, J.; Suárez Barrios, M.; Torres-López, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">149</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040105566&hterms=temporal+anomaly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtemporal%2Banomaly"> <span id="translatedtitle">Magsat to CHAMP: <span class="hlt">Magnetic</span> Satellite Explorations of Lithospheric <span class="hlt">Anomalies</span> over Kursk, Bangui and the Antarctic</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We compare crustal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps over the Kursk (Russia) and Bangui (Central African Republic) isolated <span class="hlt">anomalies</span> and the Antarctic derived from the Magsat, \\Orsted and CHAMP satellite fields. We wish to demonstrate how progress in satellite <span class="hlt">magnetic</span> missions has improved the recovery of the crustal <span class="hlt">magnetic</span> field. The 6-month long Magsat mission of 25 years ago generated two major methods of processing satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data for lithospheric studies. The first was a global perspective using spherical harmonics that emphasize the more regional and global lithospheric fields. However, these fields commonly do not resolve local <span class="hlt">anomaly</span> features in any detail. Therefore a second procedure involved the use of the individual satellite orbit or track data to recover small-scale <span class="hlt">anomalies</span> on a regional scale. We present results over prominent <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> such as Kursk, Bangui and the large Antarctic continent that demonstrate how the various analysis methods affect the recovery of crustal <span class="hlt">anomalies</span>. The more recent \\Orsted and CHAMP missions are successfully recording data with an improved accuracy and with full spatial and temporal coverage. We show and interpret the total <span class="hlt">magnetic</span> intensity <span class="hlt">anomaly</span> maps over these areas from all three satellite magnetometer data sets.</p> <div class="credits"> <p class="dwt_author">Kim, H.; Taylor, Patrick T.; vonFrese, R. R.; Kim, J. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">150</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56224503"> <span id="translatedtitle">Study on velocity <span class="hlt">spread</span> for axis-encircling electron beams generated by single <span class="hlt">magnetic</span> cusp</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The physical characteristics of an annular Pierce-type electron gun are investigated analytically. The electron gun is used in conjunction with a nonadiabatic <span class="hlt">magnetic</span> reversal and adiabatic compression region to produce an axis-encircling beam. Typical <span class="hlt">magnetic</span> field profiles that can generate zero velocity <span class="hlt">spreads</span> are obtained from the analytical calculation, taking into account initial canonical angular momentum <span class="hlt">spreads</span> at the cathode</p> <div class="credits"> <p class="dwt_author">S. G. Jeon; C. W. Baik; D. H. Kim; G. S. Park; N. Sato; K. Yokoo</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">151</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T43D2705M"> <span id="translatedtitle">Decay of natural remanent <span class="hlt">magnetization</span> of oceanic basalt on the back-arc <span class="hlt">spreading</span> axis of the southern Mariana</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Magnetic</span> <span class="hlt">anomaly</span> high on the <span class="hlt">spreading</span> axis is a well-known character of the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the ocean, which is possibly related to <span class="hlt">magnetization</span> intensity reduction of oceanic basalt due to alteration (low-temperature oxidation of titanomagnetite). For a better understanding of natural remanent <span class="hlt">magnetization</span> (NRM) of oceanic basalt, we studied rock-<span class="hlt">magnetic</span> property of basaltic rocks in the back-arc <span class="hlt">spreading</span> axis in the southern Mariana Trough. One to four meter cores were drilled from the seafloor using a Boring Machine System (BMS) in the cruise of TAIGA project (Taiga10M). Block samples were also collected during the dives of SHINKAI6500 in the cruise YK10-11. One-inch specimens drilled from the samples were used for rock-<span class="hlt">magnetic</span> measurements. NRM intensities of these specimens show a clear decrease within 2 km of the ridge axis. Progressive thermal demagnetizations of NRM show that dominant blocking-temperature components are 200-300 and 500-575 °C. Specimens from the ridge axis typically show low blocking-temperature components. On the other hand, specimens collected at 2-5 km distance from the ridge axis show both low and high blocking-temperature components. Alternating field demagnetizations of NRM, anhysteresis remanent <span class="hlt">magnetization</span> (ARM) and isothermal remanent <span class="hlt">magnetization</span> (IRM) indicate that low blocking-temperature components have lower coercivities (<40 mT) while high blocking-temperature components possibly correspond to higher coercivities. These data suggest that high blocking-temperature component is carried by titanomaghemite (or fine magnetite). On the basis of these results, the low blocking-temperature components are considered to be primary thermoremanent <span class="hlt">magnetization</span> (TRM). The high blocking-temperature components are chemical remanent <span class="hlt">magnetization</span> (CRM) acquired during low-temperature alteration which had completed within 2 km of the ridge axis. The NRM intensity shows a decrease within 2 km of the ridge axis, which is similar to a reported result from the East Pacific Rise. Similar spatial scales for the NRM reduction were observed for the ridges of different <span class="hlt">spreading</span> rate suggesting that the low-temperature alteration of oceanic basalt may result from the geological structure around the ridge axis such as active hydrothermal circulation zone rather than the crust's aging which is discussed in previous studies.</p> <div class="credits"> <p class="dwt_author">Mochizuki, N.; Nogi, Y.; Asada, M.; Yoshikawa, S.; Okino, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">152</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/52734"> <span id="translatedtitle">Airborne detection of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> associated with soils on the Oak Ridge Reservation, Tennessee</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Reconnaissance airborne geophysical data acquired over the 35,000-acre Oak Ridge Reservation (ORR), TN, show several <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over undisturbed areas mapped as Copper Ridge Dolomite (CRD). The <span class="hlt">anomalies</span> of interest are most apparent in <span class="hlt">magnetic</span> gradient maps where they exceed 0.06 nT/m and in some cases exceed 0.5 nT/m. <span class="hlt">Anomalies</span> as large as 25nT are seen on maps. Some of the <span class="hlt">anomalies</span> correlate with known or suspected karst, or with apparent conductivity <span class="hlt">anomalies</span> calculated from electromagnetic data acquired contemporaneously with the <span class="hlt">magnetic</span> data. Some of the <span class="hlt">anomalies</span> have a strong correlation with topographic lows or closed depressions. Surface <span class="hlt">magnetic</span> data have been acquired over some of these sites and have confirmed the existence of the <span class="hlt">anomalies</span>. Ground inspections in the vicinity of several of the <span class="hlt">anomalies</span> has not led to any discoveries of manmade surface materials of sufficient size to generate the observed <span class="hlt">anomalies</span>. One would expect an <span class="hlt">anomaly</span> of approximately 1 nT for a pickup truck from 200 ft altitude. Typical residual <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> have magnitudes of 5--10 nT, and some are as large as 25nT. The absence of roads or other indications of culture (past or present) near the <span class="hlt">anomalies</span> and the modeling of <span class="hlt">anomalies</span> in data acquired with surface instruments indicate that man-made metallic objects are unlikely to be responsible for the <span class="hlt">anomaly</span>. The authors show that observed <span class="hlt">anomalies</span> in the CRD can reasonably be associated with thickening of the soil layer. The occurrence of the <span class="hlt">anomalies</span> in areas where evidences of karstification are seen would follow because sediment deposition would occur in topographic lows. Linear groups of <span class="hlt">anomalies</span> on the maps may be associated with fracture zones which were eroded more than adjacent rocks and were subsequently covered with a thicker blanket of sediment. This study indicates that airborne <span class="hlt">magnetic</span> data may be of use in other sites where fracture zones or buried collapse structures are of interest.</p> <div class="credits"> <p class="dwt_author">Doll, W.E.; Beard, L.P. [Oak Ridge National Lab., TN (United States). Environmental Sciences Div.; Helm, J.M. [Univ. of Utah, Salt Lake City, UT (United States). Dept. of Geology and Geophysics</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">153</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013PhRvB..88k5119K"> <span id="translatedtitle"><span class="hlt">Anomaly</span> induced chiral <span class="hlt">magnetic</span> current in a Weyl semimetal: Chiral electronics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Electric circuits involving Weyl semimetals possess unusual properties induced by the quantum <span class="hlt">anomaly</span>. The chiral <span class="hlt">magnetic</span> current in a Weyl semimetal subjected to <span class="hlt">magnetic</span> field modifies the behavior of such circuits in a drastic way. We consider two explicit examples: (i) a circuit involving the “chiral battery” and (ii) a circuit that can be used as a “quantum amplifier” of <span class="hlt">magnetic</span> field. The unique properties of these circuits stem from the chiral <span class="hlt">anomaly</span> and may be utilized for creating “chiral electronic” devices.</p> <div class="credits"> <p class="dwt_author">Kharzeev, Dmitri E.; Yee, Ho-Ung</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">154</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850023284&hterms=baltic+basin&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbaltic%2Bbasin"> <span id="translatedtitle">Long-wavelength <span class="hlt">magnetic</span> and gravity <span class="hlt">anomaly</span> correlations on Africa and Europe</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Preliminary MAGSAT scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data were compiled for comparison with long-wavelength-pass filtered free-air gravity <span class="hlt">anomalies</span> and regional heat-flow and tectonic data. To facilitate the correlation analysis at satellite elevations over a spherical-Earth, equivalent point source inversion was used to differentially reduce the <span class="hlt">magnetic</span> satellite <span class="hlt">anomalies</span> to the radial pole at 350 km elevation, and to upward continue the first radial derivative of the free-air gravity <span class="hlt">anomalies</span>. Correlation patterns between these regional geopotential <span class="hlt">anomaly</span> fields are quantitatively established by moving window linear regression based on Poisson's theorem. Prominent correlations include direct correspondences for the Baltic shield, where both <span class="hlt">anomalies</span> are negative, and the central Mediterranean and Zaire Basin where both <span class="hlt">anomalies</span> are positive. Inverse relationships are generally common over the Precambrian Shield in northwest Africa, the Basins and Shields in southern Africa, and the Alpine Orogenic Belt. Inverse correlations also presist over the North Sea Rifts, the Benue Rift, and more generally over the East African Rifts. The results of this quantitative correlation analysis support the general inverse relationships of gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> observed for North American continental terrain which may be broadly related to <span class="hlt">magnetic</span> crustal thickness variations.</p> <div class="credits"> <p class="dwt_author">Vonfrese, R. R. B.; Olivier, R.; Hinze, W. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">155</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19840017067&hterms=baltic+basin&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbaltic%2Bbasin"> <span id="translatedtitle">Long-wavelength <span class="hlt">magnetic</span> and gravity <span class="hlt">anomaly</span> correlations of Africa and Europe</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Preliminary MAGSAT scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data were compiled for comparison with long-wavelength-pass filtered free-air gravity <span class="hlt">anomalies</span> and regional heat-flow and tectonic data. To facilitate the correlation analysis at satellite elevations over a spherical-Earth, equivalent point source inversion was used to differentially reduce the <span class="hlt">magnetic</span> satellite <span class="hlt">anomalies</span> to the radial pole at 350 km elevation, and to upward continue the first radial derivative of the free-air gravity <span class="hlt">anomalies</span>. Correlation patterns between these regional geopotential <span class="hlt">anomaly</span> fields are quantitatively established by moving window linear regression based on Poisson's theorem. Prominent correlations include direct correspondences for the Baltic Shield, where both <span class="hlt">anomalies</span> are negative, and the central Mediterranean and Zaire Basin where both <span class="hlt">anomalies</span> are positive. Inverse relationships are generally common over the Precambrian Shield in northwest Africa, the Basins and Shields in southern Africa, and the Alpine Orogenic Belt. Inverse correlations also presist over the North Sea Rifts, the Benue Rift, and more generally over the East African Rifts. The results of this quantitative correlation analysis support the general inverse relationships of gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> observed for North American continental terrain which may be broadly related to <span class="hlt">magnetic</span> crustal thickness variations.</p> <div class="credits"> <p class="dwt_author">Vonfrese, R. R. B.; Hinze, W. J. (principal investigators); Olivier, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">156</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3215468"> <span id="translatedtitle"><span class="hlt">Magnetic</span> resonance and computed tomographic features of 4 cases of canine congenital thoracic vertebral <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary"><span class="hlt">Magnetic</span> resonance and computed tomography features of 4 cases of canine congenital vertebral <span class="hlt">anomalies</span> (CVAs) are discussed. Two of the cases represent unusual presentations for such <span class="hlt">anomalies</span> that commonly affect screw-tail or toy breeds. Moreover, the combination of CVAs and a congenital peritoneo-pericardial diaphragmatic hernia has never before been imaged.</p> <div class="credits"> <p class="dwt_author">Berlanda, Michele; Zotti, Alessandro; Brandazza, Giada; Poser, Helen; Calo, Pietro; Bernardini, Marco</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">157</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50905169"> <span id="translatedtitle">Method of separating dipole <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> from geomagnetic field and application in underwater vehicle localization</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Because dipole <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> caused by ferromagnetic object or geologic structural change is mixed with geomagnetic field and difficult to calculate its magnitude, it lead to a problem for automatic underwater vehicle (AUV) localization aided by geomagnetic <span class="hlt">anomaly</span>. To solve this issue, a novel AUV localization method introducing draft depth is put forward, where vertical position of AUV relative to</p> <div class="credits"> <p class="dwt_author">Huang Yu; Hao Yan-ling</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">158</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22654139"> <span id="translatedtitle"><span class="hlt">Magnetic</span> resonance and computed tomographic features of 4 cases of canine congenital thoracic vertebral <span class="hlt">anomalies</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Magnetic</span> resonance and computed tomography features of 4 cases of canine congenital vertebral <span class="hlt">anomalies</span> (CVAs) are discussed. Two of the cases represent unusual presentations for such <span class="hlt">anomalies</span> that commonly affect screw-tail or toy breeds. Moreover, the combination of CVAs and a congenital peritoneo-pericardial diaphragmatic hernia has never before been imaged. PMID:22654139</p> <div class="credits"> <p class="dwt_author">Berlanda, Michele; Zotti, Alessandro; Brandazza, Giada; Poser, Helen; Calò, Pietro; Bernardini, Marco</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">159</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUSM.T22A..02D"> <span id="translatedtitle">The Bangui <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Is Not Of Impact Origin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Ron Girdler et al. suggested a possible impact origin for the Bangui <span class="hlt">magnetic</span> and gravity <span class="hlt">anomaly</span> in Central Africa.1 Paul DeCarli and Ron debated the subject vigorously but politely during each of his visits to California for the Fall AGU Meeting. We honor Ron's memory by continuing the debate. The striking feature of the inferred crater is its size, 800 km diameter. The three largest identified impact craters known on Earth do not exceed 200 km diameter. Grieve has estimated that, based on the record of craters on the Moon, there should be more than a hundred 1000 km-diameter impact structures on the Earth. Allowing for impacts on subsequently subducted oceanic crust, one would expect to find evidence for as many as thirty 1000 km-diameter impact craters on continental crust. If the estimated number of large craters is not grossly in error, one may infer that there could be some natural process that obliterates the evidence for very large craters. We recognize that most of these large craters will be old, ca. 4000 Myr. However, the ca. 200 km diameter Vredefort and Sudbury structures are approximately 2000 Myr old and clearly recognizable as of impact origin. We suggest that very large craters, ca 800 km dia, will probably be inundated by impact-induced volcanism. Impact-induced terrestrial volcanism has been proposed by other workers, but the detailed mechanism has not been treated quantitatively. Consequently, the concept has received little acceptance. We examine the consequences of an impact that would produce an 800 km diameter crater. We note that the final crater diameter is achieved by gravitational modification of a bowl-shaped transient crater. Studies of large lunar and terrestrial craters imply that the transient crater diameter is about half the final diameter. We therefore attempt to infer a range of impact parameters that would produce a 400 km diameter transient crater. Simple semi-empirical scaling relations have been derived from a combination of cm-scale laboratory experiments and generic computational simulations. These scaling relations imply an impacting object having a diameter in the range of 50 to 100 km, assuming a chondritic impactor and an impact velocity of 20 km/s. To assess the possibility that volcanism might be triggered, one must estimate the depth of the transient crater. The aspect ratio, crater depth/crater diameter will depend on the nature of the impactor. A nickel-iron impact will produce a relatively deeper crater than a chondrite impact. Preliminary estimates indicate that the lower bound on the depth is about 80 km. This depth appears sufficient to trigger large-scale decompression melting. Results of computational modeling of the formation of very large impact craters will be presented.. If the Bangui <span class="hlt">anomaly</span> is the fossil of a very large impact, why is there no evidence of large scale volcanism? We suggest that the answer is simple; the Bangui <span class="hlt">anomaly</span> is not of impact origin. 1R.W. Girdler, P.T. Taylor, and J.J. Frawley, Tectonophysics 212 (1992) 45-58</p> <div class="credits"> <p class="dwt_author">DeCarli, P. S.; Jones, A. P.; Price, N. J.; Price, G. D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">160</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.er.usgs.gov/publication/70012295"> <span id="translatedtitle">Random crustal <span class="hlt">magnetization</span> and its effect on coherence of short-wavelength marine <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Recent studies of DSDP samples from layer 2A of oceanic basement have found complex <span class="hlt">magnetic</span> stratigraphies that seem incompatible with the frequent existence of linear short-wavelength <span class="hlt">anomalies</span> caused by palaeomagnetic field behavior. Statistical models are developed for the lateral variation of the average <span class="hlt">magnetization</span> of layer 2A: a Poisson series for reversals of the earth's field and a stairstep random series for discrete <span class="hlt">magnetic</span> units. It is shown with the power-density spectra of these statistical models that lateral inhomogeneities must average out over distances of less than a few hundred meters. Specifically, individual <span class="hlt">magnetic</span> units of the type seen at DSDP Site 332 cannot extend uniformly for distances greater than a few hundred meters. ?? 1979.</p> <div class="credits"> <p class="dwt_author">Blakely, R. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_7");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_8");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a style="font-weight: bold;">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_10");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">161</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20000080984&hterms=strong&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dstrong"> <span id="translatedtitle">Regional Mapping of the Lunar Crustal <span class="hlt">Magnetic</span> Field: Correlation of Strong <span class="hlt">Anomalies</span> with Curvilinear Albedo Markings</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Using high-resolution regional Lunar Prospector magnetometer <span class="hlt">magnetic</span> field maps, we report here a close correlation of the strongest individual crustal <span class="hlt">anomalies</span> with unusual curvilinear albedo markings of the Reiner Gamma class.</p> <div class="credits"> <p class="dwt_author">Hood, L. L.; Yingst, A.; Zakharian, A.; Lin, R. P.; Mitchell, D. L.; Halekas, J.; Acuna, M. H.; Binder, A. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">162</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48937778"> <span id="translatedtitle">High-resolution multifluid simulations of the plasma environment near the Martian <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Three-dimensional high-resolution (?40 km), multifluid simulations of the solar wind interaction at Mars during the southern hemisphere summer solstice indicate that the region around the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can be complex and highly structured. The anomalous <span class="hlt">magnetic</span> field leads to the formation of multiple cusps and a void region where the ionosphere is eroded. Most importantly, the anomalous <span class="hlt">magnetic</span> field changes</p> <div class="credits"> <p class="dwt_author">E. M. Harnett; R. M. Winglee</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">163</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://earthweb.ess.washington.edu/eharnett/papers/2006JA012001.pdf"> <span id="translatedtitle">High-resolution multifluid simulations of the plasma environment near the Martian <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">(1) Three-dimensional high-resolution (40 km), multifluid simulations of the solar wind interaction at Mars during the southern hemisphere summer solstice indicate that the region around the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can be complex and highly structured. The anomalous <span class="hlt">magnetic</span> field leads to the formation of multiple cusps and a void region where the ionosphere is eroded. Most importantly, the anomalous <span class="hlt">magnetic</span> field</p> <div class="credits"> <p class="dwt_author">E. M. Harnett; R. M. Winglee</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">164</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005PApGe.162.2197B"> <span id="translatedtitle">Interpretation of the Gravity and <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> of the Cappadocia Region, Central Turkey</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Cappadocia region, located in Central Turkey, is characterized by widespread lava flows and volcanoclastic deposits dating from Miocene to Quaternary. Gravity and aeromagnetic <span class="hlt">anomalies</span> of the region appear to present similar high and low amplitude regions, although the aeromagnetic <span class="hlt">anomalies</span> exhibit a rather complex pattern which is thought to be caused by remanent <span class="hlt">magnetization</span>. The low-pass filtered aeromagnetic map shows a deep-seated <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> which may be linked to the widespread volcanic activity at the surface. The pseudogravity transformation of the upward continued <span class="hlt">anomaly</span> has been constructed. The pseudogravity <span class="hlt">anomaly</span> demonstrates some form of clockwise rotation. This <span class="hlt">anomaly</span> was modelled by means of a three-dimensional method. The top and bottom of the body are at 6.3km and 11km (including the flight height) from the ground surface, respectively. This deep body is ellipsoidal and extends along an E-W direction, which is in line with the regional stress direction deduced from GPS measurements. A new mobilistic dynamo-tectonic system appears to explain the body’s E-W elongation. The modelled body may be the source for the inferred geothermal energy of the region. <span class="hlt">Magnetic</span> measurements were carried out on oriented rock samples collected from outcrops of ignimbrites and basalts, providing directions and intensities of remanent <span class="hlt">magnetization</span>, susceptibilities and Koeningsberger (Q) ratios. Standard deviations of remanent directions of the Natural Remanent <span class="hlt">Magnetization</span> (NRM) display a wide scatter implying unreliability of the surface data. Reduction to pole (RTP) transformation of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> was successful with the induced <span class="hlt">magnetization</span> angle despite the complex pattern of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">Büyüksaraç, A.; Jordanova, D.; Ate?, A.; Karloukovski, V.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">165</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EPSC....8..724K"> <span id="translatedtitle">Solar wind interaction with a lunar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>: Hybrid modelling studies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Recent lunar missions have shown that the solar wind interaction with the Moon is complex and scientifically more interesting than anticipated before, as shown by new in situ plasma, neutral atom and <span class="hlt">magnetic</span> field observations. Especially, an unexpectedly high fraction of the incident solar wind protons is reflected from the surface, and an even larger fraction by the lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. This effect has been observed both by measuring deviated solar wind ion flow near the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and by observing decreased flux of energetic neutral hydrogen atoms, H-ENAs, from the surface region of strong <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. These processes affect the properties of plasma near the lunar surface. In this work we continue [1] to study the solar wind interaction with a lunar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> by a 3D hybrid model (HYB-<span class="hlt">Anomaly</span>). In the hybrid model ions are modelled as particles while electrons form a charge neutralizing massless fluid. The hybrid model also includes energetic neutral hydrogen atoms, HENAs, which are formed in charge exchange processes on the lunar surface when solar wind protons hit against it. In the presentation we analyse, based on the HYB model, properties of plasma near the lunar surface, its modification by a lunar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and the reflected flux of ions and H-ENAs, which serves as messengers for the interaction processes at the surface.</p> <div class="credits"> <p class="dwt_author">Kallio, E.; Jarvinen, R.; Alho, M.; Dyadechkin, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">166</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/42007056"> <span id="translatedtitle">Paleomagnetic determinations on Lanzarote from <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span>: Implications for the early history of the Canary Islands</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The Bouguer and aeromagnetic <span class="hlt">anomaly</span> maps of Lanzarote show a gravity high and a dipolar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> over the central part of the island, indicating one isolated source. Assuming that the structure responsible for both <span class="hlt">anomalies</span> is the same, a methodology has been designed to estimate the total <span class="hlt">magnetization</span> vector of the source, which is interpreted as a large intrusive</p> <div class="credits"> <p class="dwt_author">I. Blanco-Montenegro; F. G. Montesinos; A. García; R. Vieira; J. J. Villalaín</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">167</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012ApGeo...9..468M"> <span id="translatedtitle">Interpretation of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> by horizontal and vertical derivatives of the analytic signal</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Magnetic</span> <span class="hlt">anomalies</span> are often disturbed by the <span class="hlt">magnetization</span> direction, so we can't directly use the original <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> to estimate the exact location and geometry of the source. The 2D analytic signal is insensitive to <span class="hlt">magnetization</span> direction. In this paper, we present an automatic method based on the analytic signal horizontal and vertical derivatives to interpret the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. We derive a linear equation using the analytic signal properties and we obtain the 2D <span class="hlt">magnetic</span> body location parameters without giving a priori information. Then we compute the source structural index (expressing the geometry) by the estimated location parameters. The proposed method is demonstrated on synthetic <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> with noise. For different models, the proposed technique can both successfully estimate the location parameters and the structural index of the sources and is insensitive to noise. Lastly, we apply it to real <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from China and obtain the distribution of unexploited iron ore. The inversion results are consistent with the parameters of known ore bodies.</p> <div class="credits"> <p class="dwt_author">Ma, Guo-Qing; Du, Xiao-Juan; Li, Li-Li; Meng, Ling-Shun</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">168</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003EAEJA.....2587T"> <span id="translatedtitle">High-altitude structure of the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> using the gradient measurements in stratosphere</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">HIGH-ALTITUDE STRUCTURE OF THE <span class="hlt">MAGNETIC</span> <span class="hlt">ANOMALIES</span> USING THE GRADIENT MEASUREMENTS IN STRATOSPHERE Yu. Tsvetkov, N. ROTANOVA, M. Belikova Institute of Terrestrial <span class="hlt">Magnetism</span>, Ionosphere and Radio Wave Propagation RAS, Troitsk, Moscow Region, 142190, Russia rotanova@izmiran.rssi.ru/FAX: +7-095-3340124 Method of the recalculation of the <span class="hlt">anomaly</span> <span class="hlt">magnetic</span> field over the range of the altitudes of 20-40 km is suggested. Technique is based on the experimental data of the <span class="hlt">anomaly</span> <span class="hlt">magnetic</span> field, its vertical gradient and the gradient increment along vertical line, obtained from the aerostat gradient <span class="hlt">magnetic</span> surveys in stratosphere. The high-altitude structure of the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, obtained for the Baikal region has been constructed. These results were used to obtain the estimations of the deep <span class="hlt">magnetic</span> sources. The numerous values of the low boundary of the sources are 30-35 km. These estimations of the depth coincide with the ones, obtained from the results of the spectral analysis of the same <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">Tsvetkov, Yu.; Rotanova, N.; Belikova, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">169</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40448562"> <span id="translatedtitle">Curie point depth based on spectrum analysis of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data in East and Southeast Asia</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The bottom of the <span class="hlt">magnetized</span> crust determined from the spectral analysis of residual <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> is generally interpreted as the level of the Curie point isotherm. A method to estimate the depth extent of <span class="hlt">magnetic</span> sources (Curie point depth analysis) was applied to the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of East and Southeast Asia. Although the geologic and physiographic complexities of this area</p> <div class="credits"> <p class="dwt_author">A. Tanaka; Y Okubo; O Matsubayashi</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">170</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/45898922"> <span id="translatedtitle">Characteristics of mesospheric gravity waves near the <span class="hlt">magnetic</span> equator, Brazil, during the <span class="hlt">Spread</span>FEx campaign</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">As part of the <span class="hlt">Spread</span>FEx campaign, coordinated optical and radio measurements were made from Brazil to investigate the occurrence and properties of equatorial <span class="hlt">Spread</span> F, and to characterize the regional mesospheric gravity wave field. All-sky image measurements were made from two sites: Brasilia and Cariri located ~10° S of the <span class="hlt">magnetic</span> equator and separated by ~1500 km. In particular, the</p> <div class="credits"> <p class="dwt_author">M. J. Taylor; P.-D. Pautet; A. F. Medeiros; R. Buriti; J. Fechine; D. C. Fritts; S. L. Vadas; H. Takahashi; F. T. São Sabbas</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">171</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB261953"> <span id="translatedtitle">National <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map. Report of the National <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map Workshop, Held at Golden, Colorado, on February 17-19, 1976.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The purpose of the Workshop was to prepare a statement of the benefits, objectives, and desirable specifications and requirements of a National <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map (NMAM) and to establish a working plan for producing the map. The discussions of the Works...</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1976-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">172</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860052866&hterms=rock+magnetism&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Drock%2Bmagnetism"> <span id="translatedtitle">A remanent and induced <span class="hlt">magnetization</span> model of Magsat vector <span class="hlt">anomalies</span> over the west African craton</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Scalar and vector Magsat <span class="hlt">anomalies</span> over the west African craton are analyzed by forward and inverse models. A forward model of the Man shield is based on Liberia. Induced <span class="hlt">magnetization</span> contrasts due to sporadic iron-formations and to regional metamorphic rocks, and a contrast in remanent <span class="hlt">magnetization</span> within the lower crust are included. This combination reproduces the location, magnitude and adopted local zero level of <span class="hlt">anomalies</span> in the initial Magsat maps. An inverse model of the Reguibat shield estimates the <span class="hlt">magnetization</span> contrast of its lithosphere, and when <span class="hlt">magnetism</span> is restricted to shallower than 75 km both shields can be represented by a susceptibility contrast of +0.02. A residual <span class="hlt">anomaly</span> between the shields involves a relative deficiency of induced <span class="hlt">magnetization</span> along with other causes.</p> <div class="credits"> <p class="dwt_author">Toft, P. B.; Haggerty, S. E.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">173</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/8986364"> <span id="translatedtitle">Weak extremely-low-frequency <span class="hlt">magnetic</span> field-induced regeneration <span class="hlt">anomalies</span> in the planarian Dugesia tigrina.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We recently reported that cephalic regeneration in the planarian Dugesia tigrina was significantly delayed in populations exposed continuously to combined parallel DC and AC <span class="hlt">magnetic</span> fields. This effect was consistent with hypotheses suggesting an underlying resonance phenomenon. We report here, in a parallel series of investigations on the same model system, that the incidence of regeneration <span class="hlt">anomalies</span> presenting as tumor-like protuberances also increases significantly (P < .001) in association with exposure to weak 60 Hz <span class="hlt">magnetic</span> fields, with peak intensities ranging between 1.0 and 80.0 microT. These <span class="hlt">anomalies</span> often culminate in the complete disaggregation of the organism. Similar to regeneration rate effects, the incidence of regeneration <span class="hlt">anomalies</span> is specifically dependent upon the planaria possessing a fixed orientation with respect to the applied <span class="hlt">magnetic</span> field vectors. However, unlike the regeneration rate effects, the AC <span class="hlt">magnetic</span> field alone, in the absence of any measurable DC field, is capable of producing these <span class="hlt">anomalies</span>. Moreover, the incidence of regeneration <span class="hlt">anomalies</span> follows a clear dose-response relationship as a function of AC <span class="hlt">magnetic</span> field intensity, with the threshold for induced electric field intensity estimated at 5 microV/m. The addition of either 51.1 or 78.4 microT DC <span class="hlt">magnetic</span> fields, applied in parallel combination with the AC field, enhances the appearance of <span class="hlt">anomalies</span> relative to the 60 Hz AC field alone, but only at certain AC field intensities. Thus, whereas our previous study of regeneration rate effects appeared to involve exclusively resonance interactions, the regeneration <span class="hlt">anomalies</span> reported here appear to result primarily from Faraday induction coupling. These results together with those reported previously point to two distinct physiological effects produced in regenerating planaria by exposure to weak extremely-low-frequency (ELF) <span class="hlt">magnetic</span> fields. They further suggest that the planarian, which has recently been identified elsewhere as an excellent system for use in teratogenic investigations involving chemical teratogens, might be used similarly in teratogenic investigations involving ELF <span class="hlt">magnetic</span> fields. PMID:8986364</p> <div class="credits"> <p class="dwt_author">Jenrow, K A; Smith, C H; Liboff, A R</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">174</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMGP21B0996R"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Within Lunar Impact Basins: Constraints on the History of the Lunar Dynamo</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Previous work has shown that lunar crustal <span class="hlt">magnetization</span> has a combination of origins including shock remanent <span class="hlt">magnetization</span> in transient <span class="hlt">magnetic</span> fields and thermoremanent <span class="hlt">magnetization</span> in a steady core dynamo <span class="hlt">magnetic</span> field (e.g., Hood and Artemieva, Icarus, 2008; Richmond and Hood, JGR, 2008; Garrick-Bethell et al., Science, 2009; Hood, Icarus, 2011). In particular, <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> within the interiors of lunar impact basins and large craters provide a potentially valuable means of constraining the history of the former dynamo (Halekas et al., MAPS, 2003; Hood, 2011). These <span class="hlt">anomalies</span> likely have a thermoremanent origin owing to high subsurface temperatures reached at the time of impact and therefore require a long-lived, steady <span class="hlt">magnetic</span> field to explain their <span class="hlt">magnetization</span>. Central <span class="hlt">anomalies</span> have previously been confirmed to be present using Lunar Prospector magnetometer (LP MAG) data within several Nectarian-aged basins (Moscoviense, Mendel-Rydberg, Crisium, and Humboldtianum), implying that a dynamo existed during this lunar epoch (Hood, 2011). Here, we further analyze low altitude LP MAG data for several additional basins, ranging in age from Nectarian to Imbrian. Results indicate that <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> with a probable basin-related origin are present within at least two additional Nectarian-aged basins (Serenitatis and Humorum) and one Imbrian-aged basin (Schrodinger). No discernible <span class="hlt">anomalies</span> are present within the largest Imbrian-aged basins, Imbrium and Orientale. While there is uncertainty regarding the age of the Schrodinger basin, it has been reported to be slightly more recent than Imbrium (Wilhelms, 1984). Our initial interpretation is therefore that a dynamo likely existed during the Imbrian epoch. The absence of <span class="hlt">anomalies</span> within Imbrium and Orientale can be explained by insufficient conditions for acquisition of strong <span class="hlt">magnetization</span> (e.g., inadequate concentrations of efficient remanence carriers) following these relatively large impacts.</p> <div class="credits"> <p class="dwt_author">Richmond, N. C.; Hood, L. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">175</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..1412169V"> <span id="translatedtitle">Direct Observations of <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> on the Lunar Surface under Varying Solar Wind Conditions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In contrast to Earth, the Moon does not have a global dipolar <span class="hlt">magnetic</span> field. Since the first lunar landing with Apollo 11, we know, though, that localised <span class="hlt">magnetic</span> fields exist on the lunar surface. Measurements conducted by the Lunar Prospector magnetometer and electron reflectometer suggested that these localised <span class="hlt">magnetic</span> fields are able to deflect the impinging solar wind in favourable cases (Lin et al., Science 1998). Magnetohydrodynamic simulations support the implication that mini-magnetospheres are formed above the locations of strong localised <span class="hlt">magnetic</span> fields and can hold off the impinging solar wind (Harnett and Winglee, JGR 2002). Analysis of <span class="hlt">magnetic</span> field data from Lunar Prospector of the Reiner Gamma <span class="hlt">anomaly</span> region showed that the distortion of the <span class="hlt">magnetic</span> field of this <span class="hlt">anomaly</span> strongly depends on the impinging solar wind parameters, which was interpreted that the size and shape of the mini-magnetosphere changed with the solar wind parametes (Kurata et al., GRL 2005). Wieser et al., GRL 2010 showed that SARA, the Sub-KeV Atom Analyzer on board Chandrayaan-1, is able to detect an ENA image of the mini-magnetosphere in the measured energetic neutral atom flux. Here we analysed all orbits where CENA, the Chandrayaan-1 Energetic Neutral Analyzer, recorded data when a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> was in CENA's field-of-view. Our goal was to determine if 1) a signature of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is always visible in the ENA signal and if 2) there is a correlation between the solar wind dynamic pressure, the solar wind <span class="hlt">magnetic</span> field, the local <span class="hlt">magnetic</span> field strength and the reduction in the reflected ENA flux. Our results show that for the simplest case, i.e., the Gerasimovich <span class="hlt">anomaly</span>, there is indeed a clear correlation between the shielding efficiency, the <span class="hlt">magnetic</span> field strength and the solar wind dynamic pressure. For the other observed <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, for which the <span class="hlt">magnetic</span> fields are not only weaker but also spatially more variable than that of the Gerasimovich <span class="hlt">anomaly</span>, only in about half of the cases such a correlation was found. We therefore conclude that the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> interaction is in general quite complex and that data with higher spatial resolution and more detailed modelling is required to understand this process better.</p> <div class="credits"> <p class="dwt_author">Vorburger, A.; Wurz, P.; Barabash, S.; Wieser, M.; Futaana, Y.; Holmström, M.; Bhardwaj, A.; Dhanya, M. B.; Sridharan, R.; Asamura, K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">176</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013MeScT..24g5005Y"> <span id="translatedtitle">Characterization of CHAMP <span class="hlt">magnetic</span> data <span class="hlt">anomalies</span>: <span class="hlt">magnetic</span> contamination and measurement timing</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The CHAMP (CHAllenging Minisatellite Payload) mission ended after more than ten years in space on 19 September 2010. For achieving a high measurement accuracy of the magnetometers on CHAMP, detailed analyses of spacecraft <span class="hlt">magnetic</span> characteristics in orbit are required. A decade of continuous magnetometer and housekeeping data are a good basis for evaluating some of the effects of variable spacecraft <span class="hlt">magnetic</span> fields on the ambient field determination. It was found that some perturbations of FGM (FluxGate vector Magnetometer) or OVM (OVerhauser scalar Magnetometer) measurements are caused by stray fields induced by the power system, the ASC (advanced stellar compass) instrument or magneto-torquer currents. The <span class="hlt">magnetic</span> effect of solar currents on FGM measurements varies with the local time of the orbit and amounts to 0.2 nT. In cases when one head of the ASC instrument was blinded by the sun, sometimes transient drops in instrument current strength occur, which were accompanied by <span class="hlt">magnetic</span> disturbance signals (?0.3 nT) in FGM measurements. The <span class="hlt">magnetic</span> residual contamination of OVM data by the torquer currents was of order 0.1 nT but still detectable. An improved torquer correction matrix is derived which eliminates this effect. In-flight scalar calibration parameters revealed some of the effects of timing <span class="hlt">anomalies</span>. Time lags between FGM and OVM readings are misinterpreted by the scalar calibration as variations of the angles between some of the sensor axes. The resulting amplitudes of the <span class="hlt">anomalies</span> presented here lie in the range of some 0.1 nT, but they are systematic in nature.</p> <div class="credits"> <p class="dwt_author">Yin, Fan; Lühr, Hermann; Rauberg, Jan; Michaelis, Ingo; Cai, Hongtao</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">177</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850023282&hterms=Central+Africa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2522Central%2BAfrica%2522"> <span id="translatedtitle">Reduced to pole long-wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of Africa and Europe</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">To facilitate analysis of the tectonic framework for Africa, Europe and adjacent marine areas, MAGSAT scalar <span class="hlt">anomaly</span> data are differentially reduced to the pole and compared to regional geologic information and geophysical data including surface free-air gravity <span class="hlt">anomaly</span> data upward continued to satellite elevation (350 km) on a spherical Earth. Comparative analysis shows <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> correspond with both ancient as well as more recent Cenozoic structural features. <span class="hlt">Anomalies</span> associated with ancient structures are primarily caused by intra-crustal lithologic variations such as the crustal disturbance associated with the Bangui <span class="hlt">anomaly</span> in west-central Africa. <span class="hlt">Anomalies</span> correlative with Cenozoic tectonic elements appear to be related to Curie isotherm perturbations. A possible example of the latter is the well-defined trend of <span class="hlt">magnetic</span> minima that characterize the Alphine orogenic belt from the Atlas mountains to Eurasia. In contrast, a well-defined <span class="hlt">magnetic</span> satellite minimum extends across the stable craton from Finland to the Ural mountains. Prominent <span class="hlt">magnetic</span> maxima characterize the Arabian plate, Iceland, the Kursk region of the central Russian uplift, and generally the Precambrian shields of Africa.</p> <div class="credits"> <p class="dwt_author">Olivier, R.; Hinze, W. J.; Vonfrese, R. R. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">178</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19840017064&hterms=Central+Africa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2522Central%2BAfrica%2522"> <span id="translatedtitle">Reduced to pole long-wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of Africa and Europe</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">To facilitate analysis of the tectonic framework for Africa, Europe and adjacent marine areas, MAGSAT scalar <span class="hlt">anomaly</span> data are differentially reduced to the pole and compared to regional geologic information and geophysical data including surface free-air gravity <span class="hlt">anomaly</span> data upward continued to satellite elevation (350 km) on a spherical Earth. Comparative analysis shows <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> correspond with both ancient as well as more recent Cenozoic structural features. <span class="hlt">Anomalies</span> associated with ancient structures are primarily caused by intra-crustal lithologic variations such as the crustal disturbance associated with the Bangui <span class="hlt">anomaly</span> in west-central Africa. <span class="hlt">Anomalies</span> correlative with Cenozoic tectonic elements appear to be related to Curie isotherm perturbations. A possible example of the latter is the well-defined trend of <span class="hlt">magnetic</span> minima that characterize the Alpine orogenic belt from the Atlas mountains to Eurasia. In contrast, a well-defined <span class="hlt">magnetic</span> satellite minimum extends across the stable craton from Finland to the Ural mountains. Prominent <span class="hlt">magnetic</span> maxima characterize the Arabian plate, Iceland, the Kursk region of the central Russian uplift, and generally the Precambrian shields of Africa.</p> <div class="credits"> <p class="dwt_author">Hinze, W. J.; Vonfrese, R. R. B. (principal investigators); Olivier, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">179</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1999GeoRL..26.2279B"> <span id="translatedtitle">Behavior of oceanic crustal <span class="hlt">magnetization</span> at high temperatures: Viscous <span class="hlt">magnetization</span> and the marine <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> source layer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Although the source layer for marine <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> has been assumed to be the extrusive basalts of uppermost ocean crust, recent studies indicate that lower crustal rocks may also contribute. Because the temperature at which <span class="hlt">magnetization</span> of crustal rocks achieves long-term stability is crucial to any source layer contribution, we undertook high-temperature VRM (viscous remanent <span class="hlt">magnetization</span>) experiments on samples of basalt, dike and gabbroic sections. Samples were heated at temperature intervals up to Tc, while a <span class="hlt">magnetic</span> field was applied for periods between 6 hours and 28 days. Results show that the dike and gabbro samples achieve maximum VRM acquisition near 250°C, well below the Tc of 580°C. The basalt sample shows a peak at 68°C, also well below Tc. Results of this pilot study indicate that the critical isotherm for stable <span class="hlt">magnetization</span> acquisition is defined by the VRM behavior of the specific crustal section.</p> <div class="credits"> <p class="dwt_author">Bowles, Julie A.; Johnson, H. Paul</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">180</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20030025340&hterms=MGal&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DMGal"> <span id="translatedtitle">Satellite-Altitude Geopotential Study of the Kursk <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (KMA)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">With the successful launch of the Orsted, SAC-C and CHAMP satellites we are able to make both <span class="hlt">magnetic</span> and gravity <span class="hlt">anomaly</span> maps of the Earth's crust; <span class="hlt">magnetic</span> from all three missions and gravity with CHAMP. We have used these data to study the KMA area of Russia. This is an important region for several reasons: (1) we have already made satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps of this region and they can be integrated with the gravity data from CHAMP for a comprehensive interpretation; (2) KMA contains the largest know reserves of iron-ore in the world; and (3) there are significant ground truth data available for this region from aeromagnetic, balloon surveys and geophysical mapping, including extensive rock <span class="hlt">magnetic/paleo-magnetic</span> and geologic studies. Utilizing the gravity observations, collocated with the <span class="hlt">magnetic</span> data enabled us to make a joint interpretation. While there is a high amplitude <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> recorded over the KMA the gravity <span class="hlt">anomaly</span> at satellite altitude revealed by CHAMP is only around 3-6 mGal but is not centered on the <span class="hlt">magnetic</span> high. This would indicate that despite the fact that in the region of the KMA the rocks have a higher percentage of iron than in the surrounding formations the entire area is Archean-Proterozoic in age and therefore very dense.</p> <div class="credits"> <p class="dwt_author">Taylor, Patrick T.; Kim, Hyung Rae; vonFrese, Ralph R. B.; Potts, Laramie V.; Frawley, James J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_8");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a 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<img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_9");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a style="font-weight: bold;">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_11");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">181</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.agu.org/journals/ja/v086/iA10/JA086iA10p08435/JA086iA10p08435.pdf"> <span id="translatedtitle">The <span class="hlt">Magnetic-Anomaly</span> Model of the Jovian Magnetosphere: A Post-Voyager Assessment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We reexamine the three predictions that we previously put forth as tests for the <span class="hlt">magnetic-anomaly</span> model (in which the anomalously weak <span class="hlt">magnetic</span> field region in the northern hemisphere of Jupiter influences the outer Jovian magnetosphere by one or more plasma interaction processes), taking into account the Voyager and other recent observations. Concerning the prediction of a restricted longitude range of</p> <div class="credits"> <p class="dwt_author">V. M. Vasyliunas; A. J. Dessler</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">182</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014ApJ...790...72S"> <span id="translatedtitle">A Tale of Two <span class="hlt">Anomalies</span>: Depletion, Dispersion, and the Connection between the Stellar Lithium <span class="hlt">Spread</span> and Inflated Radii on the Pre-main Sequence</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We investigate lithium depletion in standard stellar models (SSMs) and main sequence (MS) open clusters, and explore the origin of the Li dispersion in young, cool stars of equal mass, age, and composition. We first demonstrate that SSMs accurately predict the Li abundances of solar analogs at the zero-age main sequence (ZAMS) within theoretical uncertainties. We then measure the rate of MS Li depletion by removing the [Fe/H]-dependent ZAMS Li pattern from three well-studied clusters, and comparing the detrended data. MS depletion is found to be mass-dependent, in the sense of more depletion at low mass. A dispersion in Li abundance at fixed T eff is nearly universal, and sets in by ~200 Myr. We discuss mass and age dispersion trends, and the pattern is mixed. We argue that metallicity impacts the ZAMS Li pattern, in agreement with theoretical expectations but contrary to the findings of some previous studies, and suggest Li as a test of cluster metallicity. Finally, we argue that a radius dispersion in stars of fixed mass and age, during the epoch of pre-MS Li destruction, is responsible for the <span class="hlt">spread</span> in Li abundances and the correlation between rotation and Li in young cool stars, most well known in the Pleiades. We calculate stellar models, inflated to match observed radius <span class="hlt">anomalies</span> in <span class="hlt">magnetically</span> active systems, and the resulting range of Li abundances reproduces the observed patterns of young clusters. We discuss ramifications for pre-MS evolutionary tracks and age measurements of young clusters, and suggest an observational test.</p> <div class="credits"> <p class="dwt_author">Somers, Garrett; Pinsonneault, Marc H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">183</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19840014940&hterms=kmz+geology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D.kmz%2Bgeology"> <span id="translatedtitle">Application of Magsat lithospheric modeling in South America. Part 1: Processing and interpretation of <span class="hlt">magnetic</span> and gravity <span class="hlt">anomaly</span> data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data from MAGSAT, reduced to vertical polarization and long wavelength pass filtered free air gravity <span class="hlt">anomaly</span> data of South America and the Caribbean are compared to major crustal features. The continental shields generally are more <span class="hlt">magnetic</span> than adjacent basins, oceans and orogenic belts. In contrast, the major aulacogens are characterized by negative <span class="hlt">anomalies</span>. Spherical earth <span class="hlt">magnetic</span> modeling of the Amazon River and Takatu aulacogens in northeastern South America indicates a less <span class="hlt">magnetic</span> crust associated with the aulacogens. Spherical earth modeling of both positive gravity and negative <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> observed over the Mississippi Embayment indicate the presence of a nonmagnetic zone of high density material within the lower crust associated with the aulacogen. The MAGSAT scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data and available free air gravity <span class="hlt">anomalies</span> over Euro-Africa indicate several similar relationships.</p> <div class="credits"> <p class="dwt_author">Hinze, W. J.; Braile, L. W.; Vonfrese, R. R. B. (principal investigators); Keller, G. R.; Lidiak, E. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1984-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">184</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/415620"> <span id="translatedtitle">Weak extremely-low-frequency <span class="hlt">magnetic</span> field-induced regeneration <span class="hlt">anomalies</span> in the planarian, Dugesia tigrina</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The authors recently reported that cephalic regeneration in the planarian Dugesia tigrina was significantly delayed in populations exposed continuously to combined parallel DC and AC <span class="hlt">magnetic</span> fields. This effect was consistent with hypotheses suggesting an underlying resonance phenomenon. The authors report here, in a parallel series of investigations on the same model system, that the incidence of regeneration <span class="hlt">anomalies</span> presenting as tumor-like protuberances also increases significantly (P < .001) in association with exposure to weak 60 Hz <span class="hlt">magnetic</span> fields, with peak intensities ranging between 1.0 and 80.0 {micro}T. These <span class="hlt">anomalies</span> often culminate in the complete disaggregation of the organism. Similar to regeneration rate effects, the incidence of regeneration <span class="hlt">anomalies</span> is specifically dependent upon the planaria possessing a fixed orientation with respect to the applied <span class="hlt">magnetic</span> field vectors. However, unlike the regeneration rate effects, the AC <span class="hlt">magnetic</span> field alone, in the absence of any measurable DC field, is capable of producing these <span class="hlt">anomalies</span>. Moreover, the incidence of regeneration <span class="hlt">anomalies</span> follows a clear dose-response relationship as a function of AC <span class="hlt">magnetic</span> field intensity, with the threshold for induced electric field intensity estimated at 5 {micro} V/m. The addition of either 51.1 or 78.4 {micro}T DC <span class="hlt">magnetic</span> fields, applied in parallel combination with the AC field, enhances the appearance of <span class="hlt">anomalies</span> relative to the 60 Hz AC field alone, but only at certain AC field intensities. Thus, whereas the previous study of regeneration rate effects appeared to involve exclusively resonance interactions, the regeneration <span class="hlt">anomalies</span> reported here appear to result primarily from Faraday induction coupling.</p> <div class="credits"> <p class="dwt_author">Jenrow, K.A.; Smith, C.H.; Liboff, A.R. [Oakland Univ., Rochester, MI (United States). Dept. of Physics] [Oakland Univ., Rochester, MI (United States). Dept. of Physics</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-12-31</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">185</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19950048348&hterms=magnetic+anomaly+map&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banomaly%2Bmap"> <span id="translatedtitle">Scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps of Earth derived from POGO and Magsat data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A new Polar Orbit Geophysical Observatory (POGO) scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map at 400 km altitude is presented which consists of spherical harmonics of degree 15-60. On the basis of the common features of this map with two new Magsat <span class="hlt">anomaly</span> maps, dawn and dusk, two scalar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps of the Earth are presented using two selection criteria with different levels of stringency. These selection criteria suppress the noncrustal components of the original maps by different amounts. The more stringent selection criteria seek to eliminate as much contamination as possible, at the expense of suppressing some <span class="hlt">anomaly</span> signal. This map is represented by spherical harmonics of degree 15-60. The less stringent selection criteria seek to retain as much crustal signal as possible, at the expense of also retaining some contaminating fields. This map is represented by spherical harmonics of degree 15-65. The resulting two maps are highly correlated with degree correlation coefficients greater than 0.8.</p> <div class="credits"> <p class="dwt_author">Arkani-Hamed, Jafar; Langel, Robert A.; Purucker, Mike</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">186</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830006325&hterms=Abandoned+texas+oil+fields&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAbandoned%2Btexas%2Boil%2Bfields"> <span id="translatedtitle">The intermediate wavelength <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> field of the north Pacific and possible source distributions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A technique that eliminates external field sources and the effects of strike aliasing was used to extract from marine survey data the intermediate wavelength <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> field for (B) in the North Pacific. A strong correlation exists between this field and the MAGSAT field although a directional sensitivity in the MAGSAT field can be detected. The intermediate wavelength field is correlated to tectonic features. Island arcs appear as positive <span class="hlt">anomalies</span> of induced origin likely due to variations in crustal thickness. Seamount chains and oceanic plateaus also are manifested by strong <span class="hlt">anomalies</span>. The primary contribution to many of these <span class="hlt">anomalies</span> appears to be due to a remanent <span class="hlt">magnetization</span>. The source parameters for the remainder of these features are presently unidentified ambiguous. Results indicate that the sea surface field is a valuable source of information for secular variation analysis and the resolution of intermediate wavelength source parameters.</p> <div class="credits"> <p class="dwt_author">Labrecque, J. L.; Cande, S. C.; Jarrard, R. D. (principal investigators)</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">187</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007GeoJI.171..119K"> <span id="translatedtitle">Improved <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of the Antarctic lithosphere from satellite and near-surface data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Antarctic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map compiled marine and airborne surveys collected south of 60°S through 1999 and used Magsat data to help fill in the regional gaps between the surveys. Ørsted and CHAMP satellite <span class="hlt">magnetic</span> observations with greatly improved measurement accuracies and temporal and spatial coverage of the Antarctic, have now supplanted the Magsat data. We combined the new satellite observations with the near-surface survey data for an improved <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map of the Antarctic lithosphere. Specifically, we separated the crustal from the core and external field components in the satellite data using crustal thickness variations estimated from the terrain and the satellite-derived free-air gravity observations. Regional gaps in the near-surface surveys were then filled with predictions from crustal <span class="hlt">magnetization</span> models that jointly satisfied the near-surface and satellite crustal <span class="hlt">anomalies</span>. Comparisons in some of the regional gaps that also considered newly acquired aeromagnetic data demonstrated the enhanced <span class="hlt">anomaly</span> estimation capabilities of the predictions over those from conventional minimum curvature and spherical harmonic geomagnetic field models. We also noted that the growing number of regional and world <span class="hlt">magnetic</span> survey compilations involve coverage gaps where these procedures can contribute effective near-surface crustal <span class="hlt">anomaly</span> estimates.</p> <div class="credits"> <p class="dwt_author">Kim, Hyung Rae; von Frese, Ralph R. B.; Taylor, Patrick T.; Golynsky, Alexander V.; Gaya-Piqué, Luis R.; Ferraccioli, Fausto</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">188</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.windows2universe.org/earth/interior/seafloor_spreading_interactive.html"> <span id="translatedtitle">Interactive Animation of Seafloor <span class="hlt">Spreading</span> and <span class="hlt">Magnetic</span> Field Reversals</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">This site from the University Corporation for Atmospheric Research (UCAR) offers an interactive simulation that shows how <span class="hlt">magnetic</span> stripes on the ocean bottom can reveal the age of the material and reveal plate motion. An applet shows the <span class="hlt">magnetic</span> polarities change as the user moves a compass across the ocean bottom on the screen.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2008-08-06</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">189</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820016703&hterms=West+Africa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2522West%2BAfrica%2522"> <span id="translatedtitle">The mineralogy of global <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. [rock <span class="hlt">magnetic</span> signatures and MAGSAT geological, and gravity correlations in West Africa</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Problems with the Curie balance, which severely hindered the acquisition of data, were rectified. Chemical analytical activities are proceeding satisfactorily. The <span class="hlt">magnetization</span> characteristics of metamorphic suites were analyzed and susceptibility data for a wide range of metamorphic and igneous rocks. These rock <span class="hlt">magnetic</span> signatures are discussed as well as the relationships between geology, gravity and MAGSAT <span class="hlt">anomalies</span> of West Africa.</p> <div class="credits"> <p class="dwt_author">Haggerty, S. E. (principal investigator)</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">190</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010SSRv..154..219T"> <span id="translatedtitle">Lunar <span class="hlt">Magnetic</span> Field Observation and Initial Global Mapping of Lunar <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> by MAP-LMAG Onboard SELENE (Kaguya)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">magnetic</span> field around the Moon has been successfully observed at a nominal altitude of ˜100 km by the lunar magnetometer (LMAG) on the SELENE (Kaguya) spacecraft in a polar orbit since October 29, 2007. The LMAG mission has three main objectives: (1) mapping the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> of the Moon, (2) measuring the electromagnetic and plasma environment around the Moon and (3) estimating the electrical conductivity structure of the Moon. Here we review the instrumentation and calibration of LMAG and report the initial global mapping of the lunar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> at the nominal altitude. We have applied a new de-trending technique of the Bayesian procedure to multiple-orbit datasets observed in the tail lobe and in the lunar wake. Based on the nominal observation of 14 months, global maps of lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are obtained with 95% coverage of the lunar surface. After altitude normalization and interpolation of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> field by an inverse boundary value problem, we obtained full-coverage maps of the vector <span class="hlt">magnetic</span> field at 100 km altitude and the radial component distribution on the surface. Relatively strong <span class="hlt">anomalies</span> are identified in several basin-antipode regions and several near-basin and near-crater regions, while the youngest basin on the Moon, the Orientale basin, has no <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. These features well agree with characteristics of previous maps based on the Lunar Prospector observation. Relatively weak <span class="hlt">anomalies</span> are distributed over most of the lunar surface. The surface radial-component distribution estimated from the inverse boundary value problem in the present study shows a good correlation with the radial component distribution at 30 km altitude by Lunar Prospector. Thus these weak <span class="hlt">anomalies</span> over the lunar surface are not artifacts but likely to be originated from the lunar crustal <span class="hlt">magnetism</span>, suggesting possible existence of an ancient global <span class="hlt">magnetic</span> field such as a dynamo field of the early Moon. The possibility of the early lunar dynamo and the mechanism of <span class="hlt">magnetization</span> acquisition will be investigated by a further study using the low-altitude data of the <span class="hlt">magnetic</span> field by Kaguya.</p> <div class="credits"> <p class="dwt_author">Tsunakawa, Hideo; Shibuya, Hidetoshi; Takahashi, Futoshi; Shimizu, Hisayoshi; Matsushima, Masaki; Matsuoka, Ayako; Nakazawa, Satoru; Otake, Hisashi; Iijima, Yuichi</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">191</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19850044258&hterms=CURIE+POINT&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DCURIE%2BPOINT"> <span id="translatedtitle">A review of problems and progress in studies of satellite <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A review is conducted of studies performed during the Magsat project. The obtained data are considered, taking into account questions of data availability, aspects of orbit attitude determination, ionospheric noise, a field model, and an <span class="hlt">anomaly</span> field presentation. Models for interpretation are discussed, giving attention to forward modeling, and equivalent layer inverse modeling. In an evaluation of rock property constraints, the <span class="hlt">magnetic</span> bottom is discussed along with Curie points, metamorphism and <span class="hlt">magnetization</span>, and the direction of <span class="hlt">magnetization</span>.</p> <div class="credits"> <p class="dwt_author">Mayhew, M. A.; Johnson, B. D.; Wasilewski, P. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">192</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18687508"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">anomalies</span> of forest soils in the Upper Silesia-Northern Moravia region.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Previous investigations revealed a strong <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> due to soil <span class="hlt">magnetic</span> enhancement in the industrialized cross-border area of Upper Silesia (Poland) and Northern Moravia (Czech Republic). Since industrial and urban dusts contain <span class="hlt">magnetic</span> particles, this soil <span class="hlt">magnetic</span> enhancement is assumed to be of anthropogenic origin, caused by a high concentration of atmospherically deposited <span class="hlt">magnetic</span> particles, accumulated in topsoil layers. This assumption is proved by investigations of vertical profiles of <span class="hlt">magnetic</span> susceptibility along a transect crossing the border area of the two countries. The results show that the population of <span class="hlt">magnetic</span> minerals in the organic horizon is different from that in the mineral horizons. The vertical distribution of <span class="hlt">magnetic</span> susceptibility and thermomagnetic analysis suggests negligible lithogenic contribution. The observed relationship between <span class="hlt">magnetic</span> susceptibility and some heavy metals, confirmed by micromorphological observations and microchemical analysis of <span class="hlt">magnetic</span> particles separated from the organic horizons of forest topsoil, has proved the usefulness of soil magnetometry for pollution study. PMID:18687508</p> <div class="credits"> <p class="dwt_author">Magiera, Tadeusz; Kapicka, Ales; Petrovský, Eduard; Strzyszcz, Zygmunt; Fialová, Hana; Rachwa?, Marzena</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">193</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014Tectp.624...15F"> <span id="translatedtitle">Craton vs. rift uppermost mantle contributions to <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the United States interior</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The interpretation of satellite <span class="hlt">magnetic</span> information (Magsat, Oersted, CHAMP, Swarm) requires the understanding of the mineralogy of crustal and mantle sources. Also, spectral analysis of <span class="hlt">magnetic</span> data over forearcs and cratons calls for upper mantle contribution. The prospect of such a contribution contradicts the view that the mantle is too hot and its <span class="hlt">magnetism</span> is too weak to influence <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. Here we examine the rock <span class="hlt">magnetic</span> properties of fresh mantle xenoliths from four settings across the United States: phlogopite-spinel dunites from the Bearpaw Mountains, Montana, and lherzolites/harzburgites from San Carlos, Arizona; Kilbourne Hole, New Mexico; and Knippa, Texas. Paleomagnetic results show single-component natural remanent <span class="hlt">magnetizations</span> (NRMs), which, combined with optical and secondary electron microscopy support the lack of post-eruption alteration and absence of host-rock contamination. The NRM carriers include magnetite at Bearpaw Mountain and San Carlos, and pyrrhotite at Kilbourne Hole and Knippa. These four areas show continental crust of distinct thicknesses and various geotherms. The potential mantle contribution to <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> is forward modeled using crustal thickness, current geotherm and average <span class="hlt">magnetic</span> properties of xenoliths. The San Carlos and Kilbourne Hole mantle, situated near the Rio Grande Rift is too hot and its <span class="hlt">magnetism</span> is too weak to contribute to <span class="hlt">anomalies</span>. The sulfide-dominated assemblage at Knippa does not support <span class="hlt">magnetization</span> at mantle depths. In contrast, the Bearpaw Mountains combine a relatively cold geotherm (craton) and abundance of magnetite formed at mantle depth. This cratonic mantle, metasomatized by fluids from the Farallon plate, may contribute to long wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">Friedman, S. A.; Feinberg, J. M.; Ferré, E. C.; Demory, F.; Martín-Hernández, F.; Conder, J. A.; Rochette, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">194</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56391441"> <span id="translatedtitle">Velocity <span class="hlt">Spread</span> Reduction for Axis-encircling Electron Beam Generated by Single <span class="hlt">Magnetic</span> Cusp</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Physical characteristics of an annular Pierce-type electron gun are investigated analytically. An annular electron gun is used in conjunction with a non-adiabatic <span class="hlt">magnetic</span> reversal and an adiabatic compression to produce an axis-encircling electron beam. Velocity <span class="hlt">spread</span> close to zero is realized with an initial canonical angular momentum <span class="hlt">spread</span> at the cathode when the beam trajectory does not coincide with the</p> <div class="credits"> <p class="dwt_author">S. G. Jeon; C. W. Baik; D. H. Kim; G. S. Park; N. Sato; K. Yokoo</p> <p class="dwt_publisher"></p> <p class="publishDate">2001-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">195</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19830013181&hterms=magnetic+anomaly+map&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmagnetic%2Banomaly%2Bmap"> <span id="translatedtitle">Remanent <span class="hlt">magnetization</span> and three-dimensional density model of the Kentucky <span class="hlt">anomaly</span> region</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Existing software was modified to handle 3-D density and <span class="hlt">magnetization</span> models of the Kentucky body and is being tested. Gravity and <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data sets are ready for use. A preliminary block model is under construction using the 1:1,000,000 maps. An x-y grid to overlay the 1:2,500,000 Albers maps and keyed to the 1:1,000,000 scale block models was created. Software was developed to generate a smoothed MAGSAT data set over this grid; this is to be input to an inversion program for generating the regional <span class="hlt">magnetization</span> map. The regional scale 1:2,500,000 map mosaic is being digitized using previous <span class="hlt">magnetization</span> models, the U.S. <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map, and regional tectonic maps as a guide.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">196</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMSM24B..07S"> <span id="translatedtitle">The Effect of Dissipation Mechanism on X-line <span class="hlt">Spreading</span> in 3D <span class="hlt">Magnetic</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Naturally occurring <span class="hlt">magnetic</span> reconnection generally begins in a spatially localized region and <span class="hlt">spreads</span> in the direction perpendicular to the reconnection plane as time progresses. Reconnection <span class="hlt">spreading</span> is associated with dawn-dusk asymmetries during substorms in the magnetotail and has been observed in two-ribbon flares (such as the Bastille Day flare) and laboratory experiments at the Versatile Toroidal Facility (VTF) and the <span class="hlt">Magnetic</span> Reconnection eXperiment (MRX). It was suggested that X-line <span class="hlt">spreading</span> is necessary to explain the existence of X-lines extending more than 390 Earth radii (Phan et al., Nature, 404, 848, 2006). Previous numerical studies exploring the <span class="hlt">spreading</span> of localized <span class="hlt">magnetic</span> reconnection exclusively addressed collisionless (Hall) reconnection. Here, we address the effect of dissipation mechanism has on X-line <span class="hlt">spreading</span> with and without a guide field. We compare previous results with simulations using three alternate phases of reconnection - Sweet-Parker reconnection, collisional reconnection with secondary islands, and reconnection with anomalous resistivity. We present results from three-dimensional resistive magnetohydrodynamic numerical simulations to address the nature of X-line <span class="hlt">spreading</span>. Applications to reconnection in the solar wind and corona will be discussed.</p> <div class="credits"> <p class="dwt_author">Shepherd, L. S.; Cassak, P.; Phan, T.; Shay, M. A.; Gosling, J. T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">197</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013DPS....4510709W"> <span id="translatedtitle">Plasma environment near lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and its effects on surface processes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In-situ observations and modeling work have indicated the interactions between the solar wind and lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. These interactions will alter the near-surface plasma environment in the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> regions and may have effects on the formation of unusual albedo features - the ‘lunar swirls’, and possibly also on the production (or loss) of volatiles (e.g. hydroxyl) as well as electrostatic dust transport. These interactions are complicated by the complex geometries of the lunar crustal <span class="hlt">magnetic</span> fields. Here we present a series of laboratory investigations of the plasma interactions with <span class="hlt">magnetic</span> dipole fields above an insulating surface for understanding fundamental physical processes and surface electric fields. We investigated moderate strength dipole fields in which the electrons were <span class="hlt">magnetized</span> while the ions were unmagnetized. The dipole field was oriented parallel, oblique and normal to the surface. Several physical processes have been identified, including <span class="hlt">magnetic</span> shielding and focusing, <span class="hlt">magnetic</span> mirror reflection as well as non-monotonic sheaths. Potential distributions on the surface were complex with enhanced surface charging and electric fields. Our experimental results indicate that plasma environment near the lunar surface can be greatly modified in the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> regions and may thus alter the surface processes. The latest results with a flowing plasma will also be presented.</p> <div class="credits"> <p class="dwt_author">Wang, Xu; Howes, C.; Horányi, M.; Robertson, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">198</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.P43F..06W"> <span id="translatedtitle">Laboratory studies of <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> effects on electric potential distributions near the lunar surface</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Moon does not have a global <span class="hlt">magnetic</span> field, unlike the Earth, rather it has strong crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. Data from Lunar Prospector and SELENE (Kaguya) observed strong interactions between the solar wind and these localized <span class="hlt">magnetic</span> fields. In the laboratory, a configuration of a horseshoe permanent <span class="hlt">magnet</span> below an insulating surface is used as an analogue of lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. Plasmas are created above the surface by a hot filament discharge. Potential distributions are measured with an emissive probe and show complex spatial structures. In our experiments, electrons are <span class="hlt">magnetized</span> with gyro-radii r smaller than the distance from the surface d (r < d) and ions are un-<span class="hlt">magnetized</span> with r > d. Unlike negative charging on surfaces with no <span class="hlt">magnetic</span> fields, the surface potential at the center of the <span class="hlt">magnetic</span> dipole is found close to the plasma bulk potential. The surface charging is dominated by the cold unmagnetized ions, while the electrons are shielded away. A potential minimum is formed between the center of the surface and the bulk plasma, most likely caused by the trapped electrons between the two <span class="hlt">magnetic</span> mirrors at the cusps. The value of the potential minimum with respect to the bulk plasma potential decreases with increasing plasma density and neutral pressure, indicating that the mirror-trapped electrons are scattered by electron-electron and electron-neutral collisions. The potential at the two cusps are found to be more negative due to the electrons following the <span class="hlt">magnetic</span> field lines onto the surface.</p> <div class="credits"> <p class="dwt_author">Wang, X.; Robertson, S. H.; Horanyi, M.; NASA Lunar Science Institute: Colorado Center for Lunar Dust; Atmospheric Studies</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">199</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54078148"> <span id="translatedtitle"><span class="hlt">Magnetic</span> Properties from the East Rift Zone of Kilauea: Implications for the Sources of Aeromagnetic <span class="hlt">Anomalies</span> over Hawaiian Volcanoes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Aeromagnetic studies of the Island of Hawai`i provide insights into geologic structure. High-amplitude short-wavelength <span class="hlt">anomalies</span> occur along the southwest and east rift zones (ERZ) of Kilauea, the youngest volcano on the island. These <span class="hlt">anomalies</span> have been attributed to contrast between highly <span class="hlt">magnetic</span> intrusions at depth and less <span class="hlt">magnetic</span> altered rocks. <span class="hlt">Anomalies</span> along rift zones of the older volcanoes on the</p> <div class="credits"> <p class="dwt_author">J. G. Rosenbaum; R. L. Reynolds; F. Trusdell; J. P. Kauahikaua</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">200</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA02059&hterms=magnetic+anomaly+map&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnetic%2Banomaly%2Bmap"> <span id="translatedtitle">Global Map of <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> (MAG/ER)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/>The radial <span class="hlt">magnetic</span> field measured is color coded on a global map that slows the larger craters and volcanoes (dark green), spacecraft tracks below 200 km (light green), and the dichotomy boundary (solid line).</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_9");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return 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class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_10");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">201</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=PB203726"> <span id="translatedtitle">Calculation of Pseudogravity <span class="hlt">Anomaly</span> from Total <span class="hlt">Magnetic</span> Intensity Data.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A Fortran computer program carries out the 'pseudogravity' transformation as used in potential-field geophysics, whereby a total <span class="hlt">magnetic</span> intensity map is converted into a gravitational equivalent in terms of hypothetical physical properties. The procedur...</p> <div class="credits"> <p class="dwt_author">L. Cordell</p> <p class="dwt_publisher"></p> <p class="publishDate">1971-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">202</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009Tectp.478..119M"> <span id="translatedtitle">Remanent and induced <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over a layered intrusion: Effects from crystal fractionation and magma recharge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Bjerkreim-Sokndal (BKS) norite - quartz mangerite layered intrusion is part of the early Neoproterozoic Rogaland Anorthosite Province intruded into the Fennoscandian shield in south Norway at ~ 930 Ma. The BKS is exposed over an area of 230 km 2 with a thickness of ~ 7000 m and is of economic interest for ilmenite, magnetite and apatite deposits. From the point of view of <span class="hlt">magnetic</span> minerals, in the course of fractional crystallization and magma evolution, the ilmenite becomes less Fe 3+-rich reflected by a change from ilmenite with hematite exsolution to nearly pure ilmenite. Magnetite starts to crystallize relatively late in the intrusive history, but its crystallization is interrupted by influxes of more primitive magma. The variations in aeromagnetic and ground-<span class="hlt">magnetic</span> <span class="hlt">anomalies</span> measured over the BKS can be explained in terms of the measured <span class="hlt">magnetic</span> properties of NRM, susceptibility, and hysteresis presented here, and in terms of mineralogy. Early layers in the intrusion contain hemo-ilmenite. As the magma evolved and magnetite started to crystallize, this caused a distinct change over the layering from remanence-controlled negative <span class="hlt">anomalies</span> to induced positive <span class="hlt">anomalies</span>. When new, more primitive magma was injected into the system, hemo-ilmenite returned as the major oxide and the resulting <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are again negative. The most dramatic change in the <span class="hlt">magnetic</span> signature is in the upper part of the intrusion in MCU IVe, where magnetite became a well established cumulate phase as indicated by susceptibility, but its induced <span class="hlt">magnetization</span> is overcome by large NRMs associated either with hemo-ilmenite, or with hemo-ilmenite and magnetite exsolved from pyroxenes. The average natural remanent <span class="hlt">magnetizations</span> change from ~ 3 A/m in MCU IVd, to 15 A/m in MCU IVe, and back to 2 A/m in the overlying MCU IVf, producing a strong negative remanent <span class="hlt">anomaly</span> that has been followed along strike for at least 20 km by ground-<span class="hlt">magnetic</span> measurements. The highly varied <span class="hlt">magnetic</span> properties of this intrusion, caused by varied magmatic crystallization of combinations of opaque minerals, illustrate some of the possibilities to be considered in evaluating crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">McEnroe, Suzanne A.; Brown, Laurie L.; Robinson, Peter</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">203</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002EGSGA..27.4014C"> <span id="translatedtitle">The Role of Intramap Within The Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (admap)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Within the framework of the evolving Antarctic Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (ADMAP), the existing aeromagnetic, ground and marine <span class="hlt">magnetic</span> data acquired throughout the "Antarctic sector #2" (60 degrees south and 135-255 E) are included in the digital database of the Integrated Transantarctic Mountains and Ross Sea Area <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Project (INTRAMAP). This international effort merges the mag- netic data acquired throughout the Transantarctic Mountains, the Ross Sea, Marie Bird Land, the Pacific Coast, and will begin to deal with the new data over the Wilkes Basin to be collected along the "backside of the TAM" which is the site of the ongoing ac- tivities within joint Italian, US and German scientific cooperations. The final compila- tion contributes both in delineating and in studying the major structural and geologic components of the Ross Sea Area. INTRAMAP also aims at furnishing a series of sub- sidiary benefits such as information on the crustal contribution of the Earth's <span class="hlt">magnetic</span> field and geomagnetic field modelling.</p> <div class="credits"> <p class="dwt_author">Chiappini, M.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">204</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011JCrGr.318..947S"> <span id="translatedtitle">Single crystal growth, <span class="hlt">magnetic</span> properties and Schottky <span class="hlt">anomaly</span> of HoFeO 3 orthoferrite</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The HoFeO 3 single crystal was successfully grown by the floating zone technique using a four-mirror-image-furnace under flowing air. <span class="hlt">Magnetic</span> properties of HoFeO 3 single crystal were studied over a wide temperature range. <span class="hlt">Magnetic</span> measurements under different <span class="hlt">magnetic</span> fields found that the spin reorientation transition in the crystal is well described by the earlier proposed theory with no fitting parameters. Specific heat of HoFeO 3 single crystal was measured from 2 to 300 K under zero <span class="hlt">magnetic</span> field. Schottky <span class="hlt">anomaly</span> appeared between 2 and 5 K due to the Ho 3+ spin ordering, and the <span class="hlt">anomaly</span> of specific heat due to Fe 3+ spin reorientation between 50 and 58 K was observed.</p> <div class="credits"> <p class="dwt_author">Shao, Mingjie; Cao, Shixun; Wang, Yabin; Yuan, Shujuan; Kang, Baojuan; Zhang, Jincang; Wu, Anhua; Xu, Jun</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">205</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009ApGeo...6..275S"> <span id="translatedtitle">Quantitative analysis of <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> of reinforcements in bored in-situ concrete piles?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We quantitatively study <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of reinforcement rods in bored in-situ concrete piles for the first time and summarized their <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> character. Key factors such as measuring borehole orientation, borehole-reinforcement distance, and multiple-section reinforcement rods are discussed which contributes valid and quantitative reference for using the <span class="hlt">magnetic</span> method to detect reinforcement rods. Through tests with model piles, we confirm the accuracy of theoretical computations and then utilize the law discovered in theoretical computations to explain the characteristics of the actual testing curves. The results show that the Za curves of the reinforcement rod reflect important factors regarding the reinforcement rods, such as rod length, change of reinforcement ratio, length of overlap, and etc. This research perfects the <span class="hlt">magnetic</span> method for detecting reinforcement rods in bored in-situ concrete piles and the method has great importance for preventing building contractor fraud.</p> <div class="credits"> <p class="dwt_author">Sun, Bin; Dong, Ping; Wang, Chong; Pu, Xiaoxuan; Wu, Yongjing</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">206</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1981JGR....86.7533A"> <span id="translatedtitle"><span class="hlt">Magnetic</span> storm associated enhanced particle precipitation in the South Atlantic <span class="hlt">anomaly</span> - Evidence from VLF phase measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Phase recordings of VLF signals transmitted almost entirely within the South Atlantic <span class="hlt">anomaly</span> region are analyzed to determine the vertical extent of particle precipitation previously detected at E region heights. Signals at a frequency of 13.6 kHz were transmitted from Golfo Nuevo, Argentina and received at Atibaia, Brazil. Significant perturbations characterized by advancements in received signal phase indicative of VLF reflective layer lowering are observed during times of <span class="hlt">magnetic</span> disturbances, particularly at night. Simultaneous measurements of sporadic E layer parameters over Cachoeira Paulista, Brazil also show enhancements in the blanketing frequency and the top reflected frequency at some delay with respect to <span class="hlt">magnetic</span> disturbance onset. Results reveal <span class="hlt">magnetic</span> storm associated ionization enhancements in the height region between about 110 to 70 km which is interpreted as high-energy charged particle precipitation in the South Atlantic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>.</p> <div class="credits"> <p class="dwt_author">Abdu, M. A.; Batista, I. S.; Piazza, L. R.; Massambani, O.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">207</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51234558"> <span id="translatedtitle">A New Algorithm for Depth Determination from Total <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> due to Spheres</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have developed an automatic method to determine the depth of a buried sphere from numerical second horizontal derivative <span class="hlt">anomalies</span> obtained from total field <span class="hlt">magnetic</span> data. The method is based on using a relationship between the depth and a combination of observations at symmetric points with respect to the coordinate of the projection of the center of the source in</p> <div class="credits"> <p class="dwt_author">E. M. Abdelrahman; T. M. El-Araby; E. R. Abo-Ezz; K. S. Soliman; K. S. Essa</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">208</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51888719"> <span id="translatedtitle">Characterization of lunar swirls at Mare Ingenii: A model for space weathering at <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Analysis of spectra from the Clementine ultraviolet-visible and near-infrared cameras of small, immature craters and surface soils both on and adjacent to the lunar swirls at Mare Ingenii has yielded the following conclusions about space weathering at a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. (1) Despite having spectral characteristics of immaturity, the lunar swirls are not freshly exposed surfaces. (2) The swirl surfaces are</p> <div class="credits"> <p class="dwt_author">Georgiana Y. Kramer; Jean-Philippe Combe; Erika M. Harnett; Bernard Ray Hawke; Sarah K. Noble; David T. Blewett; Thomas B. McCord; Thomas A. Giguere</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">209</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20000080790&hterms=hydrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhydrology"> <span id="translatedtitle">Hydrology in the Durius Valles Region: Evaluation of Possible Correlation with Volcanism and <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">We envision the contribution of subglacial flows, hydrothermalism and sapping in the Durius Valles system and the consequences in term of climate on Mars in recent geological times. We evaluate the possible correlation of the hydrology with volcanism and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">Cabrol, Natalie A.; Marinangeli, Lucia; Grin, Edmond A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">210</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/18475134"> <span id="translatedtitle">Role of <span class="hlt">magnetic</span> resonance imaging in different ways of presentation of Ebstein's <span class="hlt">anomaly</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The diagnosis of Ebstein's <span class="hlt">anomaly</span> is usually based on echocardiographic findings; however, cardiac <span class="hlt">magnetic</span> resonance imaging (CMR) can add useful information enabling a detailed visualization of cardiac abnormality, as well as a method of accurate physiological evaluation. CMR, in conjunction with echocardiography, offers a comprehensive non-invasive evaluation either for surgical management or ongoing follow-up of these patients. PMID:18475134</p> <div class="credits"> <p class="dwt_author">Cantinotti, Massimiliano; Bell, Aaron; Razavi, Reza</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">211</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/19760992"> <span id="translatedtitle">Energetic electron precipitation at the South Atlantic <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> - A review</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This paper reviews the status of knowledge concerning energetic electron precipitation at the South Atlantic <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (SAMA). The main purpose is to place recent results in the context of the long-standing problems about energetic electron precipitation at the SAMA region. A synopsis of results achieved in the last two decades, in relation to the various physical mechanisms responsible for</p> <div class="credits"> <p class="dwt_author">O. Pinto Jr.; W. D. Gonzales</p> <p class="dwt_publisher"></p> <p class="publishDate">1989-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">212</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.orthonurse.org/portals/0/MRI%20and%20congenital%20spine.pdf"> <span id="translatedtitle">Evaluating Congenital Spine Deformities for Intraspinal <span class="hlt">Anomalies</span> With <span class="hlt">Magnetic</span> Resonance Imaging</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Summary: The incidence of intraspinal abnormalities associ- ated with congenital spinal <span class="hlt">anomalies</span> as detected by <span class="hlt">magnetic</span> resonance imaging (MRI) is becoming better defined. In this study, 41 nonrandomized children with congenital spinal de- formities (excluding myelomeningocele) who underwent com- plete MR evaluation were reviewed. Of the 41 congenital spinal deformities, 37 demonstrated congenital scoliosis, with failure of formation in 19,</p> <div class="credits"> <p class="dwt_author">Seung-Woo Suh; John F. Sarwark; Anand Vora; Bill K. Huang</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">213</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20110007825&hterms=ion+channel&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dion%2Bchannel"> <span id="translatedtitle">Lunar Ion Transport Near <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span>: Possible Implications for Swirl Formation</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The bright swirling features on the lunar surface in areas around the Moon but most prominently at Reiner Gamma, have intrigued scientists for many years. After Apollo and later Lunar Prospector (LP} mapped the Lunar <span class="hlt">magnetic</span> fields from orbit, it was observed that these features are generally associated with crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. This led researchers to propose a number of explanations for the swirls that invoke these fields. Prominent among these include <span class="hlt">magnetic</span> shielding in the form of a mini-magnetosphere which impedes space weathering by the solar wind, <span class="hlt">magnetically</span> controlled dust transport, and cometary or asteroidal impacts that would result in shock <span class="hlt">magnetization</span> with concomitant formation ofthe swirls. In this presentation, we will consider another possibility, that the ambient <span class="hlt">magnetic</span> and electric fields can transport and channel secondary ions produced by micrometeorite or solar wind ion impacts. In this scenario, ions that are created in these impacts are under the influence of these fields and can drift for significant distances before encountering the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> when their trajectories are disrupted and concentrated onto nearby areas. These ions may then be responsible for chemical alteration of the surface leading either to a brightening effect or a disruption of space weathering processes. To test this hypothesis we have run ion trajectory simulations that show ions from regions about the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> can be channeled into very small areas near the <span class="hlt">anomalies</span> and although questions remain as to nature of the mechanisms that could lead to brightening of the surface it appears that the channeling effect is consistent with the existence of the swirls.</p> <div class="credits"> <p class="dwt_author">Keller, J. W.; Killen, R. M.; Stubbs, T. J.; Farrell, W. M.; Halekas, J. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">214</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19800009265&hterms=Sobczak&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSobczak%2BE."> <span id="translatedtitle">Comparison of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of lithospheric origin measured by satellite and airborne magnetometers over western Canada</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Crustal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data from the OGO 2, 4 and 6 (Pogo) satellites are compared with upward-continued aeromagnetic data between 50 deg -85 deg N latitude and 220 deg - 260 deg E longitude. Agreement is good both in <span class="hlt">anomaly</span> location and in amplitude, giving confidence that it is possible to proceed with the derivation and interpretation of satellite <span class="hlt">anomaly</span> maps in all parts of the globe. The data contain a <span class="hlt">magnetic</span> high over the Alpha ridge suggesting continental composition and a <span class="hlt">magnetic</span> low over the southern Canada basin and northern Canadian Arctic islands (Sverdrup basin). The low in the Sverdrup basin corresponds to a region of high heat flow, suggesting a shallow Curie isotherm. A ridge of high field, with two distinct peaks in amplitude, is found over the northern portion of the platform deposits and a relative high is located in the central portion of the Churchill province. No features are present to indicate a <span class="hlt">magnetic</span> boundary between Slave and Bear provinces, but a trend change is evident between Slave and Churchill provinces. South of 60 deg latitude a broad <span class="hlt">magnetic</span> low is located over very thick (40-50 km) crust, interpreted to be a region of low <span class="hlt">magnetization</span>.</p> <div class="credits"> <p class="dwt_author">Langel, R. A.; Coles, R. L.; Mayhew, M. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">215</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.geofisica.unam.mx/divulgacion/geofinternacional/iframes/anteriores/1999/01/lopez.pdf"> <span id="translatedtitle">Spatial and temporal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of Colima volcano, western Mexico</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Colima volcano has erupted frequently in historic times. Present activity includes the episodic growth of a lava dome within the summit crater. Total <span class="hlt">magnetic</span> field at stations spaced every 0.5 km along a 35 km long transect was measured across the eastern flank and the summit, between Atenquique and El Playón, from April 27, 1995 to May 16, 1996. Three</p> <div class="credits"> <p class="dwt_author">Héctor López Loera; Jaime Urrutia Fucugauchi</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">216</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.P41F1987Q"> <span id="translatedtitle">New Clues on the Source of the Central <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> at Haughton Impact Structure, Canada</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The 23 km-diameter Haughton impact structure, located on Devon Island, Nunavut, Canada, is one of the best-preserved medium-size complex impact structures on Earth. The impact occurred ~39 Ma ago into a target formation composed of an ~2-km thick sequence of Lower Paleozoic sedimentary rocks of the Arctic Platform overlying Precambrian metamorphic basement of the Canadian Shield (Osinski et al., 2005). Clast-rich carbonate impact melt rocks fill the crater and impact-generated hydrothermal activity took place, but since then no significant geological event has affected the area. A 900 nT-amplitude <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> with a wavelength of about 3 km is observed at the center of the crater (Pohl et al., 1988). Using high-resolution ground <span class="hlt">magnetic</span> survey and <span class="hlt">magnetic</span> property measurements on rock samples from inside and outside the structure, Quesnel et al. (2013) concluded that the source for this <span class="hlt">anomaly</span> may correspond to uplifted and hydrothermally-aletered basement rocks. Hydrothermal activity can increase rock <span class="hlt">magnetization</span> intensity by crystallization of <span class="hlt">magnetic</span> minerals, such as magnetite and/or pyrrhotite. Here, we present the results of a new ground <span class="hlt">magnetic</span> survey and electrical resistivity soundings conducted around the maximum of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. Drilling, with depths ranging from 5 m to 13 m was also conducted at three locations in the same area to ground truth the interpretation of geophysical data. The maximum of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is characterized by a ~50 m2 area of strong vertical <span class="hlt">magnetic</span> gradient and low electrical resistivity, while the surroundings show weak gradient and large resistivity. Two drill holes into this localized area show about 6 m of sandy material with some more <span class="hlt">magnetic</span> layers at about 5 m depth overlying a greenish impact melt breccia with very abundant and large clasts. Recovery in the first 9 meters is very poor, but down hole <span class="hlt">magnetic</span> gradient measurement confirms the near 6 meter <span class="hlt">magnetic</span> layer. A third hole was drilled outside the local area with strong <span class="hlt">magnetic</span> gradients and shows, starting at 2 m depth a porous gray clast-rich impact melt rock that is very similar to the impact melt rock extensively cropping out in the crater. Therefore, the three drill holes confirm that the geophysical contrast at the crater center corresponds to a geological contrast and suggest a link with hydrothermal activity. The results of laboratory measurements (<span class="hlt">magnetic</span> properties in particular) made on the drill cores will also be presented. References : Osinski, G. R. et al. 2005. MPS, 40:1759-1776 ; Pohl, J. et al. 1988. Meteoritics, 23:235-238 ; Quesnel, Y. et al. 2013. EPSL, 367:116-122.</p> <div class="credits"> <p class="dwt_author">Quesnel, Y.; Rochette, P.; Gattacceca, J.; Osinski, G. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">217</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014EGUGA..1610368Q"> <span id="translatedtitle">Joint geophysical investigation of a small scale <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> near Gotha, Germany</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In the framework of the multidisciplinary project INFLUINS (INtegrated FLUid Dynamics IN Sedimentary Basins) several airborne surveys using a full tensor <span class="hlt">magnetic</span> gradiometer (FTMG) system were conducted in and around the Thuringian basin (central Germany). These sensors are based on highly sensitive superconducting quantum interference devices (SQUIDs) with a planar-type gradiometer setup. One of the main goals was to map <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> along major fault zones in this sedimentary basin. In most survey areas low signal amplitudes were observed caused by very low <span class="hlt">magnetization</span> of subsurface rocks. Due to the high lateral resolution of a <span class="hlt">magnetic</span> gradiometer system and a flight line spacing of only 50m, however, we were able to detect even small <span class="hlt">magnetic</span> lineaments. Especially close to Gotha a NW-SE striking strong <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> with a length of 1.5 km was detected, which cannot be explained by the structure of the Eichenberg-Gotha-Saalfeld (EGS) fault zone and the rock-physical properties (low susceptibilities). Therefore, we hypothesize that the source of the <span class="hlt">anomaly</span> must be related to an anomalous <span class="hlt">magnetization</span> in the fault plane. To test this hypothesis, here we focus on the results of the 3D inversion of the airborne <span class="hlt">magnetic</span> data set and compare them with existing structural geological models. In addition, we conducted several ground based measurements such as electrical resistivity tomography (ERT) and frequency domain electromagnetics (FDEM) to locate the fault. Especially, the geoelectrical measurements were able to image the fault zone. The result of the 2D electrical resistivity tomography shows a lower resistivity in the fault zone. Joint interpretation of airborne <span class="hlt">magnetics</span>, geoelectrical and geological information let us propose that the source of the <span class="hlt">magnetization</span> may be a fluid-flow induced impregnation with iron-oxide bearing minerals in the vicinity of the EGS fault plane.</p> <div class="credits"> <p class="dwt_author">Queitsch, Matthias; Schiffler, Markus; Goepel, Andreas; Stolz, Ronny; Guenther, Thomas; Malz, Alexander; Meyer, Matthias; Meyer, Hans-Georg; Kukowski, Nina</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">218</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008JPSJ...77d4706O"> <span id="translatedtitle">1/3 <span class="hlt">Magnetization</span> <span class="hlt">Anomaly</span> in Triangular Spin Prism</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A high-field <span class="hlt">magnetization</span> process for the triangular spin prism Na17[Mn6(H2O)2(AsW9O34)2(AsW6O26)]\\cdot38H2O, which consists of six Mn2+ ions (S=5/2), has been investigated. The <span class="hlt">magnetization</span> at low temperature shows a 1/3 plateau around 5.5 T. It is examined by theoretical calculations using exact diagonalization. The experimental results can be reproduced, but only in a restricted parameter range. It implies that the plateau originates from a delicate balance of exchange couplings. We propose that the plateau is stabilized by some external perturbations, such as thermal/quantum fluctuations.</p> <div class="credits"> <p class="dwt_author">Oshima, Yugo; Nojiri, Hiroyuki; Fukaya, Keisuke; Yamase, Toshihiro</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">219</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19950007853&hterms=PangeA&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DPangeA"> <span id="translatedtitle">Towards developing an analytical procedure of defining the equatorial electrojet for correcting satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Analysis of the total <span class="hlt">magnetic</span> intensity MAGSAT data has identified and characterized the variability of ionospheric current effects as reflected in the geomagnetic field as a function of longitude, elevation, and time (daily as well as monthly variations). This analysis verifies previous observations in POGO data and provides important boundary conditions for theoretical studies of ionospheric currents. Furthermore, the observations have led to a procedure to remove these temporal perturbations from lithospheric MAGSAT <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data based on 'along-the-dip-latitude' averages from dawn and dusk data sets grouped according to longitudes, time (months), and elevation. Using this method, high-resolution lithospheric <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> maps have been prepared of the earth over a plus or minus 50 deg latitude band. These maps have proven useful in the study of the structures, nature, and processes of the lithosphere.</p> <div class="credits"> <p class="dwt_author">Ravat, Dhananjay; Hinze, William J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">220</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PhyC..477...51C"> <span id="translatedtitle">Double <span class="hlt">anomalies</span> in heat capacity and dc and ac <span class="hlt">magnetization</span> in a superconducting Pb-porous glass nanocomposite</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Studies of ac and dc <span class="hlt">magnetization</span> and heat capacity in a superconducting lead-porous glass nanocomposite were carried out. Double <span class="hlt">anomalies</span> were found on their temperature dependences at different <span class="hlt">magnetic</span> field. The positions of <span class="hlt">anomalies</span> of heat capacity and ac and dc <span class="hlt">magnetization</span> correlated with each other. The additional, low-temperature <span class="hlt">anomalies</span> shifted remarkably with increasing <span class="hlt">magnetic</span> field. The FC and FCW curves observed upon cooling and warming, respectively, showed thermal hysteresis at the second step. The peak effect on <span class="hlt">magnetization</span> loops was seen above 6 K. The low-temperature <span class="hlt">anomalies</span> in the ac and dc <span class="hlt">magnetization</span> were treated as a manifestation of transformation in the vortex system which is triggered by superconductivity in confined lead islands.</p> <div class="credits"> <p class="dwt_author">Ciou, Y. S.; Tien, C.; Charnaya, E. V.; Xing, D. Y.; Lee, M. K.; Kumzerov, Yu. A.; Pirozerskii, A. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_10");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">221</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1513217U"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Modeling of Volcanic Structure and Stratigraphy - Socorro Island, Eastern Pacific Ocean</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Results of a <span class="hlt">magnetic</span> survey of the volcanic structure of Socorro Island in the Revillagigedo Archipielago are presented. Socorro is part of a group of seamounts and oceanic islands built by volcanic activity at the northern end of the Mathematician ridge and intersection with the Clarion and Rivera fracture zones. Subaerial volcanic activity is characterized by alkaline and peralkaline compositions, marked by pre-, syn- and post-caldera phases of the Evermann volcano, and the Holocene mafic activity of the Lomas Coloradas. The <span class="hlt">magnetic</span> survey conducted in the central-southern sector of the island permits to investigate the volcanic structure and subsurface stratigraphy. Regional fields for second- and third-degree polynomials show a <span class="hlt">magnetic</span> low over the caldera, positive <span class="hlt">anomalies</span> above the pre-caldera deposits and intermediate amplitude <span class="hlt">anomalies</span> over Lomas Coloradas. Residual fields delineate the structural rim of the caldera, <span class="hlt">anomaly</span> trends for the pre- and post-caldera deposits and a broad <span class="hlt">anomaly</span> over Lomas Coloradas. Regional-residual <span class="hlt">anomalies</span>, first vertical derivative, analytical upward and downward continuations, and forward four-layer modeling are used to construct the geophysical models. Rock <span class="hlt">magnetic</span> properties were analyzed on samples collected at 24 different sites. <span class="hlt">Magnetic</span> susceptibility showed wide range of variation from ~10 to ~500 10-3 SI, corresponding to the different lithologies from trachytes and glass-rich tuffs to alkali basalts. Data have been divided into groups with low, intermediate and high values. Rock <span class="hlt">magnetic</span> analyses indicate that magnetite and titanomagnetites are the main <span class="hlt">magnetization</span> carriers. <span class="hlt">Magnetic</span> hysteresis loops indicate low coercivity minerals, with high saturation and remanent <span class="hlt">magnetizations</span> and PSD domain states. <span class="hlt">Magnetic</span> susceptibility versus temperature curves show irreversible behavior with Curie temperatures around 560-575 C, suggesting magnetite and Ti-poor titanomagnetites. Paleomagnetic directions determined on samples from one site in the pre-caldera flows and three sites in the post-caldera and Lomas Coloradas units, indicate normal polarity directions with mean declination of 350 and inclination of 37, close to the dipolar direction. Additional data on remanent <span class="hlt">magnetizations</span> reported in Sbarbori et al. (2009) support dominant normal polarities for pre- and post-caldera units, with mean directions close to the dipolar and the present-day field directions. Implications for the <span class="hlt">magnetization</span> contrasts used in modeling are to increase the intensities assigned for model units. The effective <span class="hlt">magnetizations</span> assumed for the model units have dipolar inclinations and northward declinations. The <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> shows a broad minimum over the caldera zone, a maximum over the caldera rim and a second maximum closely spaced, followed by a larger wavelength <span class="hlt">anomaly</span> over the volcano slope and the pre-caldera deposits. The maximum is associated with the caldera rim and the minimum on the outer rim edge is associated with a fracture zone or a deep pre-caldera feature. Preferred models incorporate a topographic relief for the basaltic pre-caldera unit and post-caldera deposits. Top of the pre-caldera basaltic unit lies at depths of about 300 m and up to 600 and 800 m below sea level. The Lomas Coloradas Formation is modeled with thickness of about 200-350 m. Models allow evaluation of stratigraphic distribution and thickness of pre-, syn and post-caldera units and the Lomas Coloradas Formation. Preferred models for the southern flank incorporate a pre-caldera basaltic unit with abrupt relief and syn- and post-caldera silicic deposits with Lomas Coloradas alkaline basalts covering the volcano flanks. Relief for pre-caldera basaltic unit may be associated with the volcanic conduit system for Lomas Coloradas. The structure shown at the southern end of the profile is present in the reduction to the pole, residual field and analytical continuation fields. Models for Evermann volcano show structural features associated caldera collapse, the caldera rim and the pre-caldera morphology</p> <div class="credits"> <p class="dwt_author">Urrutia-Fucugauchi, Jaime; Escorza-Reyes, Marisol; Pavon-Moreno, Julio; Perez-Cruz, Ligia; Sanchez-Zamora, Osvaldo</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">222</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009EGUGA..11.7595A"> <span id="translatedtitle">Marine <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> of the Northern Part of the Gulf of Aqaba, Dead Sea Rift</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">MARINE <span class="hlt">MAGNETIC</span> <span class="hlt">ANOMALIES</span> OF THE NORTHERN PART OF THE GULF OF AQABA, DEAD SEA RIFT Al-Zoubi (1), Z. Ben-Avraham (2), T. M. Niemi (3), E. Akawi (1), G. Tibor (4), R. Al-Rzouq (1), J.K. Hall (5), A. Abueladas (1), G. Hartman (2) (1) Surveying & Geomatics Department, Al-Balqa' Applied University, Salt, Jordan (2) Department of Geophysics & Planetary Sciences, Tel-Aviv University, Tel-Aviv, Israel (3) University of Missouri-Kansas City, USA. (4) Israel Oceanographic and Limnological Research, Haifa, Israel (5) Geological Survey of Israel, Jerusalem, Israel A high-resolution marine <span class="hlt">magnetic</span> survey in the northern part of the Gulf of Aqaba, Dead Sea Rift was carried out during October and November 2006. The survey led by an international research group (Israel, Jordan, and USA) funded by MERC, USA and aims to provide the municipalities of Aqaba and Elat a base map of active faults for seismic hazard assessment. The total <span class="hlt">magnetic</span> intensity at sea surface was measured by a proton precession magnetometer. Diurnal <span class="hlt">magnetic</span> variation was corrected from the data by using the observation located in southern part of Israel during the survey period. The correction of the external field variation was carried out based on the continuous <span class="hlt">magnetic</span> observations at a reference <span class="hlt">magnetic</span> observatory close to the survey area. For calculations of the total intensity of <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, the IGRF model was used as the core field model in accordance with the recommendation of the IAGA. Geomagnetic total intensity <span class="hlt">anomaly</span> map of the study area has been produced. The <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map shows that there are two major <span class="hlt">magnetic</span> trends appear in the study area. These are the <span class="hlt">magnetic</span> high across the northwest section of the Gulf and a <span class="hlt">magnetic</span> low across the southeast section. These two general trends are divided by a northeast-trending boundary. The <span class="hlt">magnetic</span> map reveals a complex faults system between the deep part of the Gulf as a pull-apart basin and the on land transform fault in the Araba valley.</p> <div class="credits"> <p class="dwt_author">Al-Zoubi, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">223</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860028008&hterms=Central+Africa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2522Central%2BAfrica%2522"> <span id="translatedtitle">The satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> of Ahaggar - Evidence for African Plate motion</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Ahaggar volcanic province of North Central Africa is considered a region of excess heat flow (hot spot) and hence elevated Curie isotherm. Using a modified version of the Parker FFT potential field representation, <span class="hlt">magnetic</span> signals were calculated at Magsat altitudes for models in which the African Plate is both fixed and moving. The moving-plate model extends the Curie isotherm <span class="hlt">anomaly</span> in the direction of plate motion and provides a satisfactory match to vertical component <span class="hlt">anomaly</span> data when the magnitude of plate velocity is 0.75 cm/yr. Although the signal levels are marginal for the scalar component <span class="hlt">anomalies</span> of this region, the same model provides an adequate match to this data set and is clearly preferable to a fixed-plate model.</p> <div class="credits"> <p class="dwt_author">Phillips, R. J.; Brown, C. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1985-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">224</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/16184505"> <span id="translatedtitle">Prenatal diagnosis of fetal hydrometrocolpos secondary to a cloacal <span class="hlt">anomaly</span> by <span class="hlt">magnetic</span> resonance imaging.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Fetal female urogenital <span class="hlt">anomalies</span> are often difficult to evaluate by ultrasonography, especially in late gestation. We report a case of fetal hydrometrocolpos detected at 35 weeks of gestation. Ultrasonography revealed a large retrovesical septate hypoechogenic mass in the fetal abdomen, however the sonographic findings were inconclusive. <span class="hlt">Magnetic</span> resonance imaging (MRI) confirmed that the abdominal mass was fluid-filled with a mid-plane septum in the midline posterior to the bladder, and showed a connection to the dilated uterus that was duplicated. These findings were consistent with a diagnosis of hydrometrocolpos with septate vagina and uterus didelphys. The neonate showed abdominal distension, ambiguous genitalia and anal atresia with a single perineal opening. Hydrometrocolpos was secondary to a urethral type of cloacal <span class="hlt">anomaly</span>. Aspiration of the mass and a colostomy were performed on the first postnatal day, followed by anorectoplasty at 19 months of age. MRI is a useful complementary tool for assessing fetal urogenital <span class="hlt">anomalies</span> when ultrasonography is inconclusive. PMID:16184505</p> <div class="credits"> <p class="dwt_author">Hayashi, S; Sago, H; Kashima, K; Kitano, Y; Kuroda, T; Honna, T; Nosaka, S; Nakamura, T; Ito, Y; Kitagawa, M; Natori, M</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">225</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFMGP11A0734B"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> and Rock <span class="hlt">Magnetic</span> Properties Related to Deep Crustal Rocks of the Athabasca Granulite Terrane, Northern Canada</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Athabasca granulite terrane in northernmost Saskatchewan, Canada is an exceptional exposure of lower crustal rocks having experienced several high temperature events (ca 800C) during a prolonged period of deep-crustal residence (ca 1.0 GPa) followed by uplift and exhumation. With little alteration since 1.8 Ga these rocks allow us to study ancient lower crustal lithologies. Aeromagnetic <span class="hlt">anomalies</span> over this region are distinct and complex, and along with other geophysical measurements, define the Snowbird Tectonic zone, stretching NE-SW across northwestern Canada, separating the Churchill province into the Hearne (mid-crustal rocks, amphibolite facies) from the Rae (lower crust rocks, granulite facies). Distinct <span class="hlt">magnetic</span> highs and lows appear to relate roughly to specific rock units, and are cut by mapped shear zones. Over fifty samples from this region, collected from the major rock types, mafic granulites, felsic granulites, granites, and dike swarms, as well as from regions of both high and low <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, are being used to investigate <span class="hlt">magnetic</span> properties. The intention is to investigate what is <span class="hlt">magnetic</span> in the lower crust and how it produces the <span class="hlt">anomalies</span> observed from satellite measurements. The samples studied reveal a wide range of <span class="hlt">magnetic</span> properties with natural remanent <span class="hlt">magnetization</span> ranging from an isolated high of 38 A/m to lows of 1 mA/m. Susceptibilities also range over several orders of magnitude, from 1 to 1 x10-4 SI. Magnetite is identified in nearly all samples using both low and high temperature measurements, but concentrations are generally very low. Hysteresis properties on 41 samples reveal nearly equal numbers of samples represented by PSD and MD grains, with a few samples (N=6) plotting in or close to the SD region. Low temperature measurements indicate that most samples contain magnetite, showing a marked Verway transition around 120K. Also identified in nearly half of the samples is pyrrhotite, noted by low temperature transitions at 30-35K. Preliminary results indicate that the same general lithologies can have very different <span class="hlt">magnetic</span> properties with varying concentrations of <span class="hlt">magnetic</span> minerals and with widely varying domain sizes and thus <span class="hlt">magnetic</span> behavior. Additional work is needed to fully understand the <span class="hlt">magnetic</span> signature causing the aeromagnetic <span class="hlt">anomalies</span>, but with this information we will be able to better understand the varying rock types, compositions, and exposures in lower crustal rocks, be able to predict <span class="hlt">anomaly</span> patterns, and eventually better understand the geologic history of this complex area.</p> <div class="credits"> <p class="dwt_author">Brown, L. L.; Williams, M. L.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">226</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFM.T53B1308S"> <span id="translatedtitle">Mid-Atlantic Ridge at 13-14N: Evidence of Unstable Seafloor <span class="hlt">Spreading</span> Processes From Deep-Towed <span class="hlt">Magnetic</span> Measurements</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">During cruise JC007 in March-April 2007 we recorded total <span class="hlt">magnetic</span> field <span class="hlt">anomalies</span> over two active and one defunct oceanic core complex (OCC) and the intervening seafloor. Measurements were made by towed magnetometer at the sea surface, and by the TOBI deep-towed vehicle approximately 400 m above seafloor, along 13 E-W lines about 60 km long and spaced 3 to 6 km apart. Sea-surface data show a fairly coherent central <span class="hlt">anomaly</span> on most lines, though on some it is significantly displaced from the <span class="hlt">spreading</span> axis as indicated by bathymetry and side-scan sonar data. Modelling in terms of a standard, simple (but probably unrealistic), continuous reversal sequence requires total <span class="hlt">spreading</span> rates ranging from about 15 to 40 km/Myr with offsets of the axis up to 20 km and highly asymmetric <span class="hlt">spreading</span>. The deep-towed data were corrected for the heading-dependent <span class="hlt">magnetic</span> effects of the TOBI vehicle before inversion to crustal magnetisation using the 2D Parker & Huestis (1974) procedure. These results were checked by comparing with inversions of the sea-surface field, which shows similar features at reduced resolution. The deep-towed inversion results show a rather incoherent magnetisation pattern. The central magnetisation high is nowhere more than 13 km wide, only 70% of the expected width of the Brunhes here, and several profiles yield apparently negative magnetisation over areas we expect to be of Brunhes age based on sonar and bathymetry data. This may due to a combination of destruction of magnetisation by faulting (Hussenoeder at al., 1996), departure from the 2D geometry assumed for the inversions, and departure (via tectonic rotation) from the assumed constant magnetisation direction. We are now carrying out fully 3D inversions and forward modelling guided by the structural evidence provided by sidescan and bathymetry. These results will be presented and discussed in relation to the seafloor <span class="hlt">spreading</span> history and structure of the region.</p> <div class="credits"> <p class="dwt_author">Searle, R.; Mallows, C.; Cipcigan, F.; Party, J. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">227</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.P34A..04Q"> <span id="translatedtitle">Modeling of the Central <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> at Haughton Impact Structure, Canada</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Located on Devon Island, Nunavut, Canada, the 23-km diameter Haughton impact structure is one of the best-preserved medium-size complex impact structures on Earth. The impact occurred ~39 Ma ago into a target formation composed of an ~2-km thick sequence of Lower Paleozoic sedimentary rocks of the Arctic Platform overlying Precambrian metamorphic basement of the Canadian Shield (Osinski et al., 2005). Clast-rich impact melt rocks line the crater and impact-induced hydrothermal activity took place, but since then no significant geological event has affected the area. In the 1980s, ground <span class="hlt">magnetic</span> and gravity measurements were carried out within the central part of the crater (Pohl et al., 1988). A significant <span class="hlt">anomaly</span> was discovered and coarsely modeled by a source body of simple geometry. More recently, an airborne <span class="hlt">magnetic</span> survey delivered additional data that covered the whole crater but no modeling was done (Glass et al., 2002). Here, we present the results of a new ground <span class="hlt">magnetic</span> survey accompanied by rock <span class="hlt">magnetic</span> property measurements made on all samples of the crater. This has provided additional constraints to investigate the origin of this central <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. By conducting modeling, we have been able to reveal the geometry and volume of the source body as well as its <span class="hlt">magnetization</span> properties. Our results suggest that the necessary <span class="hlt">magnetization</span> intensity to account for this <span class="hlt">anomaly</span> is too large to be associated with uplifted pre-impact target rocks. Therefore, we suggest that hydrothermal alteration could have enhanced the <span class="hlt">magnetization</span> of the central part of this crater. References : Osinski, G. R. et al. 2005. MPS, 40:1759-1776 ; Pohl, J. et al. 1988. Meteoritics, 23:235-238 ; Glass, B. J. et al. 2002, Abstract #2008. 33th LPSC</p> <div class="credits"> <p class="dwt_author">Quesnel, Y.; Gattacceca, J.; Osinski, G. R.; Rochette, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">228</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20040081281&hterms=bouguer+anomaly+gravity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dbouguer%2Banomaly%2Bgravity"> <span id="translatedtitle">Bangui <span class="hlt">Anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Bangui <span class="hlt">anomaly</span> is the name given to one of the Earth s largest crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and the largest over the African continent. It covers two-thirds of the Central African Republic and therefore the name derives from the capitol city-Bangui that is also near the center of this feature. From surface <span class="hlt">magnetic</span> survey data Godivier and Le Donche (1962) were the first to describe this <span class="hlt">anomaly</span>. Subsequently high-altitude world <span class="hlt">magnetic</span> surveying by the U.S. Naval Oceanographic Office (Project <span class="hlt">Magnet</span>) recorded a greater than 1000 nT dipolar, peak-to-trough <span class="hlt">anomaly</span> with the major portion being negative (figure 1). Satellite observations (Cosmos 49) were first reported in 1964, these revealed a 40nT <span class="hlt">anomaly</span> at 350 km altitude. Subsequently the higher altitude (417-499km) POGO (Polar Orbiting Geomagnetic Observatory) satellite data recorded peak-to-trough <span class="hlt">anomalies</span> of 20 nT these data were added to Cosmos 49 measurements by Regan et al. (1975) for a regional satellite altitude map. In October 1979, with the launch of Magsat, a satellite designed to measure crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, a more uniform satellite altitude <span class="hlt">magnetic</span> map was obtained. These data, computed at 375 km altitude recorded a -22 nT <span class="hlt">anomaly</span> (figure 2). This elliptically shaped <span class="hlt">anomaly</span> is approximately 760 by 1000 km and is centered at 6%, 18%. The Bangui <span class="hlt">anomaly</span> is composed of three segments; there are two positive <span class="hlt">anomalies</span> lobes north and south of a large central negative field. This displays the classic pattern of a <span class="hlt">magnetic</span> anomalous body being <span class="hlt">magnetized</span> by induction in a zero inclination field. This is not surprising since the <span class="hlt">magnetic</span> equator passes near the center of this body.</p> <div class="credits"> <p class="dwt_author">Taylor, Patrick T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">229</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006PhRvB..74b4413L"> <span id="translatedtitle">Dielectric <span class="hlt">anomalies</span> and spiral <span class="hlt">magnetic</span> order in CoCr2O4</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We have investigated the structural, <span class="hlt">magnetic</span>, thermodynamic, and dielectric properties of polycrystalline CoCr2O4 , an insulating spinel exhibiting both ferrimagnetic and spiral <span class="hlt">magnetic</span> structures. Below Tc=94K the sample develops long-range ferrimagnetic order, and we attribute a sharp phase transition at TS?27K to the onset of long-range spiral <span class="hlt">magnetic</span> order. Neutron measurements confirm that the structure remains cubic at 80K and at 11K ; the <span class="hlt">magnetic</span> ordering by 11K is seen to be rather complex. Density functional theory supports the view of a ferrimagnetic semiconductor with <span class="hlt">magnetic</span> interactions consistent with noncollinear ordering. Capacitance measurements on CoCr2O4 show a sharp decrease in the dielectric constant at TS , but also an <span class="hlt">anomaly</span> showing thermal hysteresis falling between approximately T=50 and 57K . We tentatively attribute the appearance of this higher-temperature dielectric <span class="hlt">anomaly</span> to the development of short-range spiral <span class="hlt">magnetic</span> order, and discuss these results in the context of utilizing dielectric spectroscopy to investigate noncollinear short-range <span class="hlt">magnetic</span> structures.</p> <div class="credits"> <p class="dwt_author">Lawes, G.; Melot, B.; Page, K.; Ederer, C.; Hayward, M. A.; Proffen, Th.; Seshadri, R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">230</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19860058984&hterms=bouguer+anomaly+gravity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dbouguer%2Banomaly%2Bgravity"> <span id="translatedtitle">Magsat equivalent source <span class="hlt">anomalies</span> over the southeastern United States - Implications for crustal <span class="hlt">magnetization</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Magsat crustal <span class="hlt">anomaly</span> field depicts a previously-unidentified long-wavelength negative <span class="hlt">anomaly</span> centered over southeastern Georgia. Examination of Magsat ascending and descending passes clearly identifies the anomalous region, despite the high-frequency noise present in the data. Using ancillary seismic, electrical conductivity, Bouguer gravity, and aeromagnetic data, a preliminary model of crustal <span class="hlt">magnetization</span> for the southern Appalachian region is presented. A lower crust characterized by a pervasive negative <span class="hlt">magnetization</span> contrast extends from the New York-Alabama lineament southeast to the Fall Line. In southern Georgia and eastern Alabama (coincident with the Brunswick Terrane), the model calls for lower crustal <span class="hlt">magnetization</span> contrast of -2.4 A/m; northern Georgia and the Carolinas are modeled with contrasts of -1.5 A/m. Large-scale blocks in the upper crust which correspond to the Blue Ridge, Charlotte belt, and Carolina Slate belt, are modeled with <span class="hlt">magnetization</span> contrasts of -1.2 A/m, 1.2 A/m, and 1.2 A/m respectively. The model accurately reproduces the amplitude of the observed low in the equivalent source Magsat <span class="hlt">anomaly</span> field calculated at 325 km altitude and is spatially consistent with the 400 km lowpass-filtered aeromagnetic map of the region.</p> <div class="credits"> <p class="dwt_author">Ruder, M. E.; Alexander, S. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">231</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003EAEJA.....1663E"> <span id="translatedtitle">Gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of the Cyprus arc and tectonic implications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In present day, eastern Mediterranean is controlled by the collision of the African and Eurasian plates and displacements of Arabian, Anatolian and Aegean micro-plates. The boundary between African and Eurasian plates is delineated by the Hellenic arc and Pliny-Strabo trench in the west and the Cyprus arc and a diffuse fault system of the Eastern Anatolian Fault zone in the east. The available gravity and <span class="hlt">magnetic</span> data from the easternmost Mediterranean allow to subdivide this basin into three provinces: the northeastern Mediterranean north of the Cyprus Arc; the Levant Basin south of the Cyprus Arc and east of the line that roughly continues the Suez rift trend toward the Gulf of Antalya, between Cyprus and Anaximander Mountains; and the Mediterranean Ridge, Herodotus Basin west of this line. High <span class="hlt">anomalies</span> observed in Cyprus and the sea region at the south is prominent in the gravity data. The Bouguer gravity <span class="hlt">anomaly</span> reaches its maximum values over Cyprus, where it is most probably caused by high dense Troodos ophiolites. The uplifted oceanic crust causes high Bouguer <span class="hlt">anomaly</span> also seen in the vicinity of Eratosthenes Seamount. Another result obtained from gravity data is that the crust under Herodotos and Rhodes basins is somehow oceanic and Anaximander, Eratosthenes and Cyprus are continental fragments. There are no linear <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the Mediterranean. But there are <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over the Eratosthenes seamount and as well as from Cyprus to the Antalya basin due to the ophiolitic bodies. In Cyprus, the last compressional deformations were defined near the Miocene/Pliocene boundary. The extensional deformation associated with the Antalya basin appears to be separated by a zone of the Florence rise and Anaximander Mountains affected by differential tectonic movements. Eratosthenes Seamount is a positive crustal feature in the process of collision with Cyprus along an active margin; there is clearly a potential tectonic relationship to the onland geology of Cyprus. Eratosthenes is in the process of actively being underthrust both northwards and southwards under opposing margins.</p> <div class="credits"> <p class="dwt_author">Ergün, M.; Okay, S.; Sari, C.; Oral, E. Z.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">232</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1997JGR...10218307B"> <span id="translatedtitle">Three-dimensional interpretation of the KTB gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A combination of a closely spaced surface gravity survey with a high-resolution helicopter aeromagnetic survey as well as borehole gravity and magnetometer measurements allowed a detailed three-dimensional (3-D) modeling of the <span class="hlt">anomalies</span> at the KTB drill site. The models could be constrained by new evidence from a 3-D seismic survey and by structural geology and petrophysical data from drill cores and cuttings. The source body for the positive gravity <span class="hlt">anomaly</span> consist of high-density metabasite. The vertical derivative of the Bouguer <span class="hlt">anomaly</span> does not resemble the aeromagnetic <span class="hlt">anomaly</span> in all areas, indicating that parts of the metabasites are more or less nonmagnetic. Surprisingly and confirming the observation in other deep drill holes into continental crystalline basement rocks, pyrrhotite is the dominant <span class="hlt">magnetic</span> mineral below a depth of about 300 m. Magnetite mainly occurs in the depth intervals 360-520 m and 7300-7900 m. The lower interval causes the anomalous vertical gradient of 60 nT/km for the geomagnetic field. The occurrence of strongly <span class="hlt">magnetic</span> minerals in the borehole down to about 3000 m correlates with the lithology, while in the deeper parts it is more related to fissures and fault zones where chemical processes (reduction/oxidation) are active.</p> <div class="credits"> <p class="dwt_author">Bosum, W.; Casten, U.; Fieberg, F. C.; Heyde, I.; Soffel, H. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">233</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998E%26PSL.161..243G"> <span id="translatedtitle">A different pattern of ridge segmentation and mantle Bouguer gravity <span class="hlt">anomalies</span> along the ultra-slow <span class="hlt">spreading</span> Southwest Indian Ridge (15°30'E to 25°E)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The results of a recent bathymetric and geophysical investigation of a ˜650 km-long portion of the very slowly opening (16 mm/yr full rate) Southwest Indian Ridge (SWIR) between 15°30'E and 25°E are presented. Bathymetry and mantle Bouguer gravity <span class="hlt">anomalies</span> (MBA), caused by variations in crustal thickness and/or crustal and upper mantle densities, show different characteristics from those observed at faster <span class="hlt">spreading</span> centers like the Mid-Atlantic Ridge (MAR) (20-30 mm/yr full rate). With the exception of the Du Toit Transform, none of the ridge-axis discontinuities have offsets greater than 10 km and few of the discontinuities have clearly defined off-axis traces. The MBA patterns associated with individual segments are much more complex than the simple circular bull's eyes lows reported along the MAR. While the short wavelength ridge segment length is comparable to that of the MAR, there is little correlation with MBA amplitude and segment length and axial relief. Furthermore, an eastward propagating magma source and an ˜84 km-long zone of oblique <span class="hlt">spreading</span> appears to define a fundamental boundary along the SWIR between two 250-300 km-long sections characterized by distinctly different axial morphology and gravity signatures. We interpret these results to indicate a long-wavelength segmentation pattern of the underlying upwelling mantle. Melt separates from the upwelling mantle at the base of the lithosphere and is channeled to the surface along dikes. Fissure eruptions within the rift valley build linear ridges defining a short-wavelength spatial pattern of ridge segmentation that is not directly related to the segmentation pattern of the upwelling mantle. Our results and interpretation are quite different than that predicted by extending current models of the faster <span class="hlt">spreading</span> MAR to these ultra-slow <span class="hlt">spreading</span> rates.</p> <div class="credits"> <p class="dwt_author">Grindlay, Nancy R.; Madsen, John A.; Rommevaux-Jestin, Celine; Sclater, John</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">234</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFM.P51E1762H"> <span id="translatedtitle">Study of interaction between plasma flow and <span class="hlt">magnetic</span> dipole field: Understanding plasma environment in lunar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> regions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In-situ observations and modeling work have indicated strong interactions between the solar wind plasma and lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. These interactions will alter the near-surface plasma environment in the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> regions and be responsible for the formation of unusual albedo features, the so-called ';lunar swirls', and the production (or loss) of volatiles (e.g. hydroxyl), as well as electrostatic dust transport. We have done a series of laboratory experiments to study the fundamental physical processes governing the plasma (non-flowing) interactions with <span class="hlt">magnetic</span> dipole fields above an insulating surface. The interactions were found very dynamic, including, for example, a highly non-uniform surface charge distribution. Here we present preliminary results of plasma flow interactions with the dipole fields with our newly developed large ion source (cross-section 24 cm in diameter, ion energy up to 30 eV, ion Mach number >>1). We will show the effects of ion energy and current on the plasma dynamics and surface charging. This study will enable us to better predict the plasma environment in the lunar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> regions, as well as associated geological features and possible dust activities.</p> <div class="credits"> <p class="dwt_author">Howes, C.; Wang, X.; Horanyi, M.; Robertson, S. H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">235</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://pubs.usgs.gov/of/2004/1202/"> <span id="translatedtitle"><span class="hlt">Magnetic</span> Properties of Quaternary Deposits, Kenai Peninsula, Alaska -- Implications for Aeromagnetic <span class="hlt">Anomalies</span> of Upper Cook Inlet</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">We measured <span class="hlt">magnetic</span> susceptibilities of exposed Quaternary deposits on several beach cliffs and river banks on the Kenai Peninsula near Soldotna, Alaska. Data, descriptions, and photos from nine sites are included in this report. The mean susceptibility for Quaternary materials in this region is approximately 2.5 x 10-3 SI units. This is sufficiently <span class="hlt">magnetic</span> to produce subtle aeromagnetic <span class="hlt">anomalies</span> such as those observed to correlate with topographic features in the region of the measurements. The highest susceptibilities measured (greater than 20 x 10-3 SI units) may help, at least in part, to explain moderate amplitude aeromagnetic <span class="hlt">anomalies</span> observed elsewhere in Cook Inlet, particularly those relating to structures showing Quaternary movement. Comparison of measured beach cliff susceptibility and susceptibility predicted from idealized formulas and two-dimensional cliff models suggests that measured susceptibilies underestimate true bulk susceptibility by 20 percent to 50 percent in this region.</p> <div class="credits"> <p class="dwt_author">Saltus, R. W.; Haeussler, P. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">236</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010EGUGA..1215444G"> <span id="translatedtitle">Circum-Arctic mapping project: new <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map of the Arctic (to 60 degrees N)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">An international effort to compile Circum-Arctic geophysical and bedrock data has been conducted by several national agencies (Russia-VSEGEI and VNIIO, Sweden-SGU, Finland-GTK, Denmark-GEUS, USA-USGS, Canada-GSC, Germany-BGR and Norway-NGU) since 2005. This project aims to produce an atlas that will comprise geological and geophysical digital maps at a scale of 1: 5 million scale for the Arctic region limited by the 60 degree North latitude. New published and classified <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> gridded data from each participant group were gathered and converted to a common datum (WGS84) and format. The Greenland region <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> grid (Verhoef et al., 1996) has been updated with new aeromagnetic surveys performed in West Greenland between 1992-2001 (Rasmussen, 2002), and in the Nares Strait area (Damaske & Oakey, 2006; Oakey & Damaske, 2006). The oceanic area east of Greenland (NE Atlantic) contains most of the aeromagnetic data used in the Verhoef et al., (1996)'s compilation (pre-1990) plus new aeromagnetic surveys over offshore Norway collected up to 2007 (Olesen et al., 1997; Olesen et al., 2007; Gernigon et al., 2008). The gridded data has been upward continued to 1 km above ground or sea-level and trimmed around the areas of major overlaps. The Alaska USGS aeromagnetic compilation has been used as the "master grid" for merging the major gridded data sets together and the downward continued lithospheric <span class="hlt">magnetic</span> field model MF6 derived from satellite data (Maus et al., 2008) has been used as a regional reference surface. We have used a blending function over the area of overlap in order to smooth the transition from one grid to the other (GridKnit, GEOSOFT). The resulting grid has been re-sampled to a 2 km grid cell. In order to construct the final Circum-Arctic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> grid (CAMP-M) we have adopted the approach used by several research groups for compiling the World Digital <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map (WDMAM) and used near-surface <span class="hlt">magnetic</span> data for the short wavelength component of the compilation and the satellite derived <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> for the long wavelength (Hemant et al., 2007; Maus et al., 2007). MF6 extends to spherical harmonics degree 120 (333 km wavelength) and therefore it is able to provide consistent long wavelength information between 300 and 400 km. This information is mainly related to regional deeper and/or thicker portions of the <span class="hlt">magnetic</span> sources within the crust. We have prepared two versions for the CAMP-M <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> grid. The first one combines short wavelength components of regional grids (less than 400 km) with long wavelengths (400 km) of the MF6 model. The second one combines short wavelengths of regional datasets (obtained by filtering with a cosine squared taper to remove the wavelengths in the waveband between 307 and 333 km and larger, with the MF6 model (to degree 120). We have selected Model 1 as the new Circum-Arctic <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Map.</p> <div class="credits"> <p class="dwt_author">Gaina, Carmen</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">237</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/bg7m8108l6231438.pdf"> <span id="translatedtitle">A New Algorithm for Depth Determination from Total <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> due to Spheres</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have developed an automatic method to determine the depth of a buried sphere from numerical second horizontal derivative\\u000a <span class="hlt">anomalies</span> obtained from total field <span class="hlt">magnetic</span> data. The method is based on using a relationship between the depth and a combination\\u000a of observations at symmetric points with respect to the coordinate of the projection of the center of the source in</p> <div class="credits"> <p class="dwt_author">E. M. Abdelrahman; T. M. El-Araby; E. R. Abo-Ezz; K. S. Soliman; K. S. Essa</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">238</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/19069391"> <span id="translatedtitle">[Hygienic characteristics of the Kursk <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> area and morbidity in the aboriginal population].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The megablock of the Kursk <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> area in the center of which the Kursk region is located is a large structure occupying the central part of the East-European platform. The Zhelezhnogorsky, Rylsky, and Dmitriyevsky Districts show the highest childhood morbidity. The environmental factor, the geomagnetic field specified by iron-ore deposits that occupy more than 30% of the territory of the Kursk Region, is one of the factors forming the health status of the region. PMID:19069391</p> <div class="credits"> <p class="dwt_author">Zabroda, N N; Artemenko, M V</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">239</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/55527681"> <span id="translatedtitle">Marine <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> of the Northern Part of the Gulf of Aqaba, Dead Sea Rift</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">MARINE <span class="hlt">MAGNETIC</span> <span class="hlt">ANOMALIES</span> OF THE NORTHERN PART OF THE GULF OF AQABA, DEAD SEA RIFT Al-Zoubi (1), Z. Ben-Avraham (2), T. M. Niemi (3), E. Akawi (1), G. Tibor (4), R. Al-Rzouq (1), J.K. Hall (5), A. Abueladas (1), G. Hartman (2) (1) Surveying & Geomatics Department, Al-Balqa' Applied University, Salt, Jordan (2) Department of Geophysics & Planetary Sciences, Tel-Aviv</p> <div class="credits"> <p class="dwt_author">A. Al-Zoubi</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">240</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003CG.....29...91R"> <span id="translatedtitle">LIMAT: a computer program for least-squares inversion of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over long tabular bodies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">A popular method for the inversion of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in total vertical or horizontal field over thin sheet thick dike and vertical fault is presented. The <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> over thin sheet may be expressed as a polynomial of the form FX2+ C1FX+ C2F+ C3X3+ C4X2+ C5X+ C6 The initial parameters of the source are obtained from the coefficients C1,C2,…, C6 by inverting a 6×6 matrix. The thick dike and the vertical fault are an ensemble of thin sheets. So the same initial solution obtained for the thin sheet model can be used for the thick dike and the vertical fault. Besides, in this method the computer calculates the initial solution by using all the discrete <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> values and the corresponding distances as an input. The initial solution thus obtained is modified in an iterative process using non-linear least-squares regression by employing Marquardt's algorithm. The regional value that is subjective in manual interpretation is also adjusted in this method to obtain a close fit. A computer program in FORTRAN 77 is presented and used to interpret synthetic and practical data and the efficacy of the results are discussed.</p> <div class="credits"> <p class="dwt_author">Raju, D. Ch. Venkata</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-02-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_11");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">241</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.agu.org/journals/jb/v088/iB04/JB088iB04p03403/JB088iB04p03403.pdf"> <span id="translatedtitle">Investigation of a Vine-Matthews <span class="hlt">Magnetic</span> Lineation From a Submersible: The Source and Character of Marine <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Brunhes reversal transition on the flanks of the East Pacific Rise near 21øN. While the sea level <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are less than average in clarity for the East Pacific Rise, a 'three-dimensional' inversion of deep-tow data reveals a sharp, strike-linear polarity transition less than 1.8 km wide (Macdonald et al., 1980a). These measurements have been augmented by mounting a vertical</p> <div class="credits"> <p class="dwt_author">Ken C. Macdonald; Stephen P. Miller; Bruce P. Luyendyk; Tanya M. Atwater; Loren Shure</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">242</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP33A..01G"> <span id="translatedtitle">Martian meteorites and Martian <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>: a new perspective from NWA 7034 (Invited)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> observed above the Martian Noachian crust [1] require strong crustal remanent <span class="hlt">magnetization</span> in the 15-60 A/m range over a thickness of 20-50 km [2,3]. The Martian rocks available for study in the form of meteorites do contain <span class="hlt">magnetic</span> minerals (magnetite and/or pyrrhotite) but in too small amount to account for such strong remanent <span class="hlt">magnetizations</span> [4]. Even though this contradiction was easily explained by the fact that Martian meteorites (mostly nakhlites and shergottites) are not representative of the Noachian Martian crust, we were left with no satisfactory candidate lithology to account for the Martian <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. The discovery in the Sahara of a new type of Martian meteorite (NWA 7034 [5] and subsequent paired stones which are hydrothermalized volcanic breccia) shed a new light on this question as it contains a much larger amount of ferromagnetic minerals than any other Martian meteorite. We present here a study of the <span class="hlt">magnetic</span> properties of NWA 7034, together with a review of the <span class="hlt">magnetic</span> properties of thirty other Martian meteorites. <span class="hlt">Magnetic</span> measurements (including high and low temperature behavior and Mössbauer spectroscopy) show that NWA 7034 contains about 15 wt.% of magnetite with various degrees of substitution and maghemitization up to pure maghemite, in the pseudo-single domain size range. Pyrrhotite, a common mineral in other Martian meteorites is not detected. Although it is superparamagnetic and cannot carry remanent <span class="hlt">magnetization</span>, nanophase goethite is present in significant amounts confirming that NWA 7034 is the most oxidized Martian meteorite studied so far, as already indicated by the presence of maghemite (this study) and pyrite [5]. These <span class="hlt">magnetic</span> properties show that a kilometric layer of a lithology similar to NWA 7034 <span class="hlt">magnetized</span> in a dynamo field would be enough to account for the strongest Martian <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. Although the petrogenesis of NWA 7034 is still debated, as the brecciation could be either of volcanic or impact origin [5,6,7], it appears that pervasive (and possibly shock-induced) hydrothermalism affecting the uppermost crust in the presence of a dynamo field during the Noachian is a viable scenario to account for the observed <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. Such a scenario is supported by the Noachian or even pre-Noachian age of NWA 7034 [8,9] and its chemical and mineralogical compositions that match the ones of the inferred Noachian crust [5]. The natural remanent <span class="hlt">magnetization</span> of the NWA 7034 samples studied so far had been obliterated by the strong <span class="hlt">magnets</span> used by meteorite hunters, but work is underway to obtain samples that may have kept their original Martian <span class="hlt">magnetization</span>. References [1] Acuña M.H. et al. 1999. Science 284:790-793 [2] Langlais B. et al. 2004. JGR 109, doi: 10.1029/2003JE002048 [3] Quesnel Y. et al. 2007. Planet. Space Sci. 55:258-269 [4] Rochette P. et al. 2005 MAPS 40:529-540 [5] Agee C.B. et al. 2013. Science 339:780-785 [6] Hewins R.H. et al. 2013. 44th LPSC, abstract#2385 [7] Wittmann et al. 2013. 76th MetSoc meeting, abstract#5272 [8] Humayun et al. 2013. 76th MetSoc meeting, abstract#5198 [9] Nyquist et al. 2013. 76th MetSoc meeting, abstract#5318.</p> <div class="credits"> <p class="dwt_author">Gattacceca, J.; Rochette, P.; Scozelli, R. B.; Munayco, P.; Agee, C. B.; Quesnel, Y.; Cournede, C.; Geissman, J. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">243</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMGP51A1311H"> <span id="translatedtitle">Origin of Strong Lunar <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span>: More Detailed Mapping in Regions Antipodal to Young Large Basins</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Previous work has found evidence that the largest concentrations of strong lunar crustal <span class="hlt">magnetic</span> fields are in regions antipodal to four young large lunar basins: Orientale, Imbrium, Crisium, and Serenitatis (Mitchell et al., Icarus, 2008; and references therein). A preliminary model for the production of lunar basin antipodal <span class="hlt">magnetic</span> signatures has been developed (Hood and Artemieva, Icarus, 2008; Gattacceca et al., EPSL, 2010). The model involves shock <span class="hlt">magnetization</span> of crustal materials in the presence of a transient <span class="hlt">magnetic</span> field amplified by the expanding ionized vapor-melt cloud as it converges in the antipodal region. The model does not exclude a core dynamo; any ambient <span class="hlt">magnetic</span> field (external solar wind or internal core dynamo) can be amplified in the antipodal zone. In this paper, we report further efforts to map in more detail Lunar Prospector magnetometer data in regions antipodal to young lunar basins. In addition to the four basins identified above, we also consider the polar Schrodinger basin, which is one of the three youngest lunar basins and which has not been previously considered in this context. We apply a direct mapping method (see Hood, Icarus, 2011 for details) to produce more complete maps of lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> at low altitudes over the central far side and over the north polar region. We also consider geologic data and spacecraft imagery to identify unusual modified terrain, which may be indicative of shock modification in the same basin antipodal zones. Previous work indicates the existence of such terrain antipodal to Imbrium, Orientale, and Serenitatis, as well as antipodal to the Caloris basin on Mercury. Results first confirm the concentrations of <span class="hlt">anomalies</span> antipodal to Orientale, Imbrium, Crisium, and Orientale, and the occurrence of modified terrain in three of the four basin antipode zones (see, e.g., Richmond et al., JGR, 2005). In addition, we report here evidence for a large concentration of <span class="hlt">anomalies</span> that is centered within 5 to 8 degrees of the Schrodinger antipode; this is the largest concentration of strong <span class="hlt">anomalies</span> in the north polar region (60N to the pole). Examinations of LROC imagery suggest the possible presence of modified terrain in the same area. If these provisional results are confirmed by later detailed studies, this would represent the fifth young lunar basin with an antipodal <span class="hlt">magnetic</span> signature.</p> <div class="credits"> <p class="dwt_author">Hood, L. L.; Richmond, N.; Spudis, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">244</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002AGUSMGP42A..02D"> <span id="translatedtitle">Correlations Between In Situ and Remotely Sensed <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> on the Lunar Prospector Mission</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Lunar Prospector mission provides two complementary measurements of Lunar <span class="hlt">magnetic</span> fields. The magnetometer (MAG) measures the vector <span class="hlt">magnetic</span> field at the spacecraft position, while estimates of the <span class="hlt">magnetic</span> field strength at the Lunar surface are derived remotely using the electron reflectometer (ER) measurements of the electron loss cone angle. In this work we study correlations between these two data sets with several goals in mind. First, since the ER instrument depends on some knowledge of the electron trajectories in order to determine the <span class="hlt">magnetic</span> field footprint on the surface, we wish to assess the importance of strong <span class="hlt">magnetic</span> field curvature in the determination of the location of the reflection points measured by the ER. Second, we wish to explore the utility of using the ER data as a lower boundary condition for models attempting to downward extend the <span class="hlt">magnetic</span> field topology as measured by the MAG instrument on the spacecraft. Initial results using well isolated <span class="hlt">anomalies</span> in areas such as Reiner Gamma and the Apollo 16 landing site indicate that for strong <span class="hlt">anomalies</span> (~50 nT at 20-30 km altitude) corrections to the electron reflection points may be on the order of 1 degree in latitude or longitude at the surface. The <span class="hlt">magnetic</span> fields of these sites and other similar examples were modeled using a simple <span class="hlt">magnetic</span> dipole approximation. Sites with a more complex <span class="hlt">magnetic</span> topology such as the Crisium antipode may be too difficult to model with a simple collection of dipoles as the run times for fitting routines increases dramatically. Spherical Cap Harmonic Analysis (SCHA) may be an appropriate tool to model these larger regional <span class="hlt">anomalies</span>, and we discuss the possibility of using the ER data as a lower boundary condition at the surface for this technique. The end goal of our work is to remove at least some of the ambiguities inherent in any downward extension of orbital magnetometer data, using a synthesis of the in situ <span class="hlt">magnetic</span> field data measured from orbit and ER estimates of the actual surface fields.</p> <div class="credits"> <p class="dwt_author">Delory, G. T.; Mitchell, D. L.; Halekas, J. S.; Lin, R. P.; Frey, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">245</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=AD678810"> <span id="translatedtitle">Sea-Floor <span class="hlt">Spreading</span> - Another Rift.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">A recent survey of intense east-west <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> between the Galapagos Islands and South America revealed a relatively small area with a pattern of symmetry about an axis that resembles the pattern of the great oceanic rises. A sea-floor <span class="hlt">spreading</span> ...</p> <div class="credits"> <p class="dwt_author">A. D. Raff</p> <p class="dwt_publisher"></p> <p class="publishDate">1968-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">246</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3835637"> <span id="translatedtitle">Congenital Variants and <span class="hlt">Anomalies</span> of the Pancreas and Pancreatic Duct: Imaging by <span class="hlt">Magnetic</span> Resonance Cholangiopancreaticography and Multidetector Computed Tomography</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Though congenital <span class="hlt">anomalies</span> of the pancreas and pancreatic duct are relatively uncommon and they are often discovered as an incidental finding in asymptomatic patients, some of these <span class="hlt">anomalies</span> may lead to various clinical symptoms such as recurrent abdominal pain, nausea and vomiting. Recognition of these <span class="hlt">anomalies</span> is important because these <span class="hlt">anomalies</span> may be a surgically correctable cause of recurrent pancreatitis or the cause of gastric outlet obstruction. An awareness of these <span class="hlt">anomalies</span> may help in surgical planning and prevent inadvertent ductal injury. The purpose of this article is to review normal pancreatic embryology, the appearance of ductal anatomic variants and developmental <span class="hlt">anomalies</span> of the pancreas, with emphasis on <span class="hlt">magnetic</span> resonance cholangiopancreaticography and multidetector computed tomography.</p> <div class="credits"> <p class="dwt_author">Erden, Ayse; Turkoglu, Mehmet Akif; Yener, Ozlem</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">247</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19770006644&hterms=magnetic+anomaly+map&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banomaly%2Bmap"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">anomaly</span> map of North America south of 50 degrees north from Pogo data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map produced from Pogo data for North America and adjacent ocean areas is presented. At satellite elevations <span class="hlt">anomalies</span> have wavelengths measured in hundreds of kilometers, and reflect regional structures on a large scale. Prominent features of the map are: (1) a large east-west high through the mid-continent, breached at the Mississippi Embayment; (2) a broad low over the Gulf of Mexico; (3) a strong gradient separating these features, which follows the Southern Appalachian-Ouachita curvature; and (4) a high over the Antilles-Bahamas Platform which extends to northern Florida. A possible relationship between the high of the mid-continent and the 38th parallel lineament is noted.</p> <div class="credits"> <p class="dwt_author">Mayhew, M. A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1976-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">248</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19730056572&hterms=cosmos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcosmos"> <span id="translatedtitle">The detection of 'intermediate' size <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in Cosmos 49 and OGO 2, 4, 6 data.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Benkova, Dolginov and Simonenko have recently reported the presence of intermediate size <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> from Cosmos 49 data and hypothesized a crustal and/or upper mantle origin for these. We have examined the spherical harmonic models of the internal potential function, based on the OGO 2, 4 and 6 data and verified the locations and amplitudes of those <span class="hlt">anomalies</span> with wavelengths of approximately 4000 km. The patterns of delta-F so computed were then compared with the IZMIRAN maps and also were analyzed statistically, in both the spatial and frequency domains, using residuals computed from the raw Cosmos 49 data. The two sets of data were thus derived from completely independent sets of observations and field references. The two patterns are shown to agree very well over the whole earth surface up to the 50 deg latitude limit of Cosmos 49.</p> <div class="credits"> <p class="dwt_author">Regan, R. D.; Davis, W. M.; Cain, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">249</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/15672369"> <span id="translatedtitle">Morphological <span class="hlt">anomalies</span> in pollen tubes of Actinidia deliciosa (kiwi) exposed to 50 Hz <span class="hlt">magnetic</span> field.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">The role of the pollen grain, with respect to the reproductive process of higher plants, is to deliver the spermatic cells to the embryo sac for egg fertilisation. Delivery occurs through the pollen tube, a self produced organ that is generated when the pollen grain reaches the stigma surface. The effect of <span class="hlt">magnetic</span> fields on pollen tube growth was reported in a recent publication by Germanà et al. Pollen tube growth is an interesting candidate for the detailed study of the effects of electromagnetic fields on cytoplasmic structures and organelles. In this research Actinidia deliciosa (kiwifruit) pollen grains were germinated in the presence of an alternating <span class="hlt">magnetic</span> field (50 Hz). Our results, although of preliminary nature, show that pollen tube growth is affected by <span class="hlt">magnetic</span> fields. The analysis of the observed <span class="hlt">anomalies</span> in the pollen tube appear to be the result of changes in the ionic charges within the pollen tube cytoplasm. PMID:15672369</p> <div class="credits"> <p class="dwt_author">Dattilo, Arduino M; Bracchini, Luca; Loiselle, Steven A; Ovidi, Elisa; Tiezzi, Antonio; Rossi, Claudio</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">250</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.T23B2259Z"> <span id="translatedtitle">Processing and interpretation for Gravity and <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> in the Daba Mountain and Periphery Areas</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Between Yangxian and Xiangfan the Dabashan nappe structural belt links the Hannan block west and the Huangling block east. The Dabashan bow-like folding belt was formed during late Jurassic and superposed on Triassic folds. To achieve an improved overall understanding of the deep tectonics of the Dabashan nappe structural belt, with new deep reflected seismic and other geophysical data as constraints, we processed and interpreted the gravity and <span class="hlt">magnetic</span> data in this area. The result shows that the Sichuan basin and Daba mountain lie in between the Longmenshan gravity gradient belt and Wulingshan gravity gradient belt. The positive <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> around the Nanchong-Tongjiang-Wanyuan-Langao and the Shizhu are caused by the crystalline basement. The modeling of the gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the Daba mountain and adjacent area shows that the crystalline basementt around the Nanchong-Tongjiang-Wanyuan-Langao stretches approximately underneath the Wafangdian fault near the Ziyang in the direction of northeast. The <span class="hlt">magnetic</span> field boundary along the Zhenba-Wanyuan-Chengkou-Zhenping indicates the location of the major boundary of the Dabashan nappe thrusting above the Sichuan Basin. This boundary might be the division between the south Dabashan structural element and the north Dabashan structural element. The low gravity <span class="hlt">anomaly</span> between the Tongjiang and Chengkou might be partly caused by the thickened lower crust. The local low gravity <span class="hlt">anomaly</span> to the south of Chengkou-Wanyuan might be mainly caused by the Mesozoic strata of low density in the Dabashan foreland depression. The Moho uplifts gently from the center of the Sichuan Basin to the Daba mountain. But the shape of the Moho is not the enantiomorph approximately with the corresponding topography of the Daba mountain. This implies that the Daba mountain is not isostatically compensated on a local scale according to the classical isostatical theory. The evidence reveals that the intra-continent subduction in Dabieshan, Dabashan and other places in central China occurred in Late Jurassic. The isostatical compensation should have been finished during the long period of time. This phenomenon will be studied in virtue of the modern isostatical theory. This work was supported by Crust Probe Project of China (SINOPROBE-02, SINOPROBE-08-02), the Natural Science Foundation of China (Nos. 40830316, 40774026, 40874045 ), China Geological Survey (Nos. 1212010611809, 1212010711813, 1212010811033), scientific research project for public welfare from the Ministry of Land and Resources of China (No. 200811021), and the Basic outlay of scientific research work from the Ministry of Science and Technology of China (No. J0803).</p> <div class="credits"> <p class="dwt_author">Zhang, J.; Gao, R.; Li, Q.; Zhang, S.; Guan, Y.; Wang, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">251</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PApGe.169.2193M"> <span id="translatedtitle">An Improved Analytic Signal Technique for the Depth and Structural Index from 2D <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This paper presents a new inversion method for the interpretation of 2D <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data, which uses the combination of the analytic signal and its total gradient to estimate the depth and the nature (structural index) of an isolated <span class="hlt">magnetic</span> source. However, our proposed method is sensitive to noise. In order to lower the effect of noise, we apply upward continuation technique to smooth the <span class="hlt">anomaly</span>. Tests on synthetic noise-free and noise corrupted <span class="hlt">magnetic</span> data show that the new method can successfully estimate the depth and the nature of the causative source. The practical application of the technique is applied to measured <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data from Jurh area, northeast China, and the inversion results are in agreement with the inversion results from Euler deconvolution of the analytic signal.</p> <div class="credits"> <p class="dwt_author">Ma, Guoqing; Du, Xiaojuan</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">252</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2002JAESc..21..111V"> <span id="translatedtitle">Bouguer <span class="hlt">anomaly</span> of the Godavari basin, India and <span class="hlt">magnetic</span> characteristics of rocks along its coastal margin and continental shelf</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Bouguer <span class="hlt">anomaly</span> map of the Godavari basin has delineated several transverse and median ridges that have divided this basin into several sub-basins. Modelling of a gravity profile in the central part of the basin suggests 5.0 km of Gondwana sediments and high density rocks along the shoulders which may represent upthrusted lower crustal rocks related to the Eastern Ghats orogeny. The total intensity <span class="hlt">magnetic</span> map of the coastal part of the Godavari basin shows a well-defined <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> of approximately 200 nT along the coast which coincides with the Kaza basement ridge. The modelling of this <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> indicates 2-2.5 km of sediments over the Kaza ridge and 5.5-6 km thick sediments in the depressions towards the west of this ridge which are constrained from the basement configuration based on seismic sections in the surrounding region. The Kaza ridge, with a susceptibility of 10 -4 SI units, appears to be composed of basic rocks which may be part of the exposed Eastern Ghats towards the west. This <span class="hlt">magnetic</span> map also shows several high amplitude short wavelength <span class="hlt">anomalies</span> which are caused by sub-surface basic rocks. These basic rocks are related to the Rajahmundry trap, equivalent to the Deccan traps of late Cretaceous age, and are exposed nearby by. Modelling of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> across the continental shelf, off the coast of the Godavari basin, suggests an almost 45° inclined contact away from shore at a depth of 2.5 km and having a thickness of 3.5 km. However, this <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> could be matched only with a remanent <span class="hlt">magnetization</span> with declination 310° and inclination -67° which corresponds to the direction of <span class="hlt">magnetization</span> reported for the Rajmahal traps.</p> <div class="credits"> <p class="dwt_author">Venkata Raju, D. Ch; Rajesh, R. S.; Mishra, D. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2002-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">253</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5289108"> <span id="translatedtitle"><span class="hlt">Magnetic</span> declination control of the equatorial F region dynamo electric field development and <span class="hlt">spread</span> F</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">We have carried out a comparative study of the evening prereversal enhancements in the equatorial F region vertical ionization drift velocities (V/sub z/) over Fortaleza (4 /sup 0/S, 38 /sup 0/W), Brazil, and Jicamarca (12 /sup 0/S, 77 /sup 0/W), Peru, two <span class="hlt">magnetic</span> equatiorial stations in the American zone. The results show profound dissimilarities in the seasonal trends in the times and widths of the V/sub z/ prereversal peak, which reflect in the <span class="hlt">spread</span> F characteristics as well, at the two stations. The dissimilarities are shown to be arising mainly from the difference in the <span class="hlt">magnetic</span> field declination angles that causes differences in the conjugate E region sunset durations and, hence, in the F region polarization electric field development rates at the two stations.</p> <div class="credits"> <p class="dwt_author">Abdu, M.A.; Bittencourt, J.A.; Batista, I.S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">254</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3180979"> <span id="translatedtitle">The developing role of fetal <span class="hlt">magnetic</span> resonance imaging in the diagnosis of congenital cardiac <span class="hlt">anomalies</span>: A systematic review</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Advances in the fetal <span class="hlt">magnetic</span> resonance imaging (MRI) over the last few years have resulted in the exploring the use of fetal MRI to detect congenital cardiac <span class="hlt">anomalies</span>. Early detection of congenital cardiac <span class="hlt">anomalies</span> can help more appropriately manage the infant's delivery and neonatal management. MRI offers anatomical and functional studies and is a safe adjunct that can help more fully understand a fetus’ cardiac anatomy. It is important for the obstetricians and pediatric cardiologists to be aware of the recent advancements in fetal MRI and it`s potential utility in diagnosing congenital cardiac <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">Loomba, Rohit S; Chandrasekar, Suraj; Shah, Parinda H; Sanan, Prateek</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">255</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19770063418&hterms=Central+Africa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2522Central%2BAfrica%2522"> <span id="translatedtitle">Reduction and treatment of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of crustal origin in satellite data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The problem of proper reduction and treatment of the residual total <span class="hlt">magnetic</span> field observed on satellite orbits is studied. The reduction procedure used for Pogo satellite data is reviewed, and a procedure is presented for reducing the residual total field observed on satellite orbits to a spherical surface. Several examples based on selected models are provided to demonstrate the accuracy of the formulas developed for continuation of the satellite data from an irregular to a spherical surface. This procedure is tested on a set of Pogo data covering the area that contains the Bangui <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in central Africa. A technique is also given for determining the field components on a spherical surface and calculating the total field in any fixed direction of the geomagnetic field.</p> <div class="credits"> <p class="dwt_author">Bhattacharyya, B. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">1977-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">256</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19990115917&hterms=Arctic+Ocean&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%253A%2522Arctic%2BOcean%2522"> <span id="translatedtitle">A Review of <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Field Data for the Arctic Region: Geological Implications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal <span class="hlt">magnetic</span> field studies. These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential <span class="hlt">anomaly</span> data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While <span class="hlt">Magnetic</span> <span class="hlt">anomaly</span> data represent the main focus of this study recently derived satellite gravity data (Laxon and McAdoo, 1998) are playing a major role in Arctic studies.</p> <div class="credits"> <p class="dwt_author">Taylor, Patrick T.; vonFrese, Ralph; Roman, Daniel; Frawley, James J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">257</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19990117091&hterms=Arctic+Ocean&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%253A%2522Arctic%2BOcean%2522"> <span id="translatedtitle">A Review of <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Field Data for the Arctic Region: Geological Implications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Due to its inaccessibility and hostile physical environment remote sensing data, both airborne and satellite measurements, has been the main source of geopotential data over the entire Arctic region. Ubiquitous and significant external fields, however, hinder crustal <span class="hlt">magnetic</span> field studies These potential field data have been used to derive tectonic models for the two major tectonic sectors of this region, the Amerasian and Eurasian Basins. The latter is dominated by the Nansen-Gakkel or Mid-Arctic Ocean Ridge and is relatively well known. The origin and nature of the Alpha and Mendeleev Ridges, Chukchi Borderland and Canada Basin of the former are less well known and a subject of controversy. The Lomonosov Ridge divides these large provinces. In this report we will present a summary of the Arctic geopotential <span class="hlt">anomaly</span> data derived from various sources by various groups in North America and Europe and show how these data help us unravel the last remaining major puzzle of the global plate tectonic framework. While <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data represent the main focus of this study recently derived satellite gravity data are playing a major role in Arctic studies.</p> <div class="credits"> <p class="dwt_author">Taylor, Patrick T.; vonFrese, Ralph; Roman, Daniel; Frawley, James J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">258</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/23215607"> <span id="translatedtitle">Observation of an unusual <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in the superconducting mixed state of heavy-fermion compound UBe13 by precise dc <span class="hlt">magnetization</span> measurements.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We have performed precise dc <span class="hlt">magnetization</span> measurements for a single crystal of UBe(13) down to 0.14 K, up to 80 kOe. We observed a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in the superconducting (SC) mixed state at a field, named H(Mag)(*) (~ 26 kOe, at 0.14 K), implying that UBe(13) has a <span class="hlt">magnetically</span> unusual SC state. We studied the <span class="hlt">magnetization</span> curves of UBe(13), assuming that the H(Mag)(*) <span class="hlt">anomaly</span> originates from (1) and unusual SC diamagnetic response, or (2) a peculiarity of the normal-state <span class="hlt">magnetization</span> due to vortices in the SC mixed state. The origin of the H(Mag)(*) <span class="hlt">anomaly</span> is discussed. PMID:23215607</p> <div class="credits"> <p class="dwt_author">Shimizu, Yusei; Haga, Yoshinori; Ikeda, Yoichi; Yanagisawa, Tatsuya; Amitsuka, Hiroshi</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-11-21</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">259</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMGP33B..02M"> <span id="translatedtitle">Long-Wavelength <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> and Tectonic Divisions of the Tasmanides, Eastern Australia.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Aeromagnetic data over eastern Australia reveal a pattern of domains defined by systematic and uniform regional highs and lows, emphasised by low-pass filtering, over which are superimposed shorter (<20 km) wavelength <span class="hlt">anomalies</span> whose disposition is clearly related to mappable geology and its inferred subsurface continuation. Long baseline levelling accomplished through Geoscience Australia's AWAGS program has served to clarify the definition of these <span class="hlt">magnetic</span> domains, and to confirm that they are not an artefact of grid merging. Geothermal and teleseismic data indicate that neither variation in Curie depth nor upper mantle magnetisation can produce the pattern of long-wavelength <span class="hlt">magnetic</span> domains. Hence, domain-wide variations in magnetisation at the middle crustal (> 10 km depth) level are presumably the cause of these long-wavelength features. Although reversed polarity remanence, possibly carried by laminar hematite, could contribute to deeply sourced negative <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>, the correspondence of <span class="hlt">magnetic</span> low domains with the Proterozoic Curnamona Craton and the Ordovician Macquarie Arc, and of a high domain with the western Lachlan Orogen floored by Cambrian ocean crust, suggests that the control may be simply stark contrasts in lower to middle crustal susceptibility. Implicit in this analysis is a division of the domains by middle crust type into two categories, continental versus oceanic, with implications for the tectonic evolution of the Tasmanides. Contrary to previous interpretations, the Macquarie Arc was apparently built on a sliver of continental crust, and the Thomson Orogen is a compound feature, in which oceanic crust was accreted to an arc likewise floored by continental material.</p> <div class="credits"> <p class="dwt_author">Musgrave, R. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">260</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP11A..08S"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">anomaly</span> analysis of the Ionian Sea: Is it the oldest in-situ ocean fragment of the world?</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">It is well known that the Ionian Sea is characterized by thin (8-11 km) crystalline crust, thick (5-7 km) sedimentary cover, and low heat flow, typical for a Mesozoic (at least) basin. Yet seismic data have not yielded univocal interpretations, and a debate has developed on the oceanic vs. 'thinned continental' nature of the Ionian basin. Here we analyze the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> pattern of the Ionian Sea, and compare it to synthetic fields produced by a geopotential field generator, considering realistic crust geometry. The Ionian basin is mostly characterized by slightly negative <span class="hlt">magnetic</span> residuals, and by a prominent positive (150 nT at sea level) 'B' <span class="hlt">anomaly</span> at the northwestern basin margin. We first test continental crust models, considering a homogeneous crystalline crust with K=1x10-3, then a 5 km thick deep crustal layer of serpentinite (K=1x10-1). First model yields insignificant <span class="hlt">anomalies</span>, while the second gives an <span class="hlt">anomaly</span> pattern anti-correlated with the observed residuals. We subsequently test oceanic crust models, considering a 2 km thick 2A basaltic layer with K=5x10-3, <span class="hlt">magnetic</span> remanence of 5 A/m, and a unique <span class="hlt">magnetic</span> polarity (no typical oceanic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> stripes are apparent in the observed data set). <span class="hlt">Magnetic</span> remanence directions were derived from Pangean-African paleopoles in the 290-190 Ma age window. Only reverse-polarity models reproduce the B <span class="hlt">anomaly</span>, and among them the 220-230 Ma models best approximate <span class="hlt">magnetic</span> features observed on the abyssal plain and at the western basin boundary. The Ionian Sea turns out to be the oldest preserved oceanic floor known so far. Reference Speranza, F., L. Minelli, A. Pignatelli, and M. Chiappini (2012), The Ionian Sea: The oldest in situ ocean fragment of the world?, J. Geophys. Res., 117, B12101, doi:10.1029/2012JB009475.</p> <div class="credits"> <p class="dwt_author">Speranza, F.; Minelli, L.; Pignatelli, A.; Chiappini, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_12");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a 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title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">261</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004AGUSMGP31A..15G"> <span id="translatedtitle">Lineated Near Bottom <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Over an Oceanic Core Complex, Atlantis Massif (Mid-Atlantic Ridge at 30°N)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Despite significant effort during the four decades since the Vine-Matthews-Morley hypothesis was first advanced, the relative importance of lower crustal (and possibly upper mantle) sources in generating lineated marine <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> remains uncertain. Remanence measurements from samples obtained by drilling or dredging provide the most direct evidence that these deeper layers can be significant <span class="hlt">anomaly</span> sources. Near bottom <span class="hlt">anomaly</span> measurements over tectonic exposures of the lower crust/upper mantle can yield valuable complementary information (e.g., patterns of polarity boundaries) as well as provide constraints on the timing and uplift history of these exposures. Here we report results from a near bottom <span class="hlt">magnetic</span> survey of the Atlantis Massif, an oceanic core complex that formed within the past 1.5-2 Myr at the intersection of the Mid-Atlantic Ridge (30°N) and the Atlantis transform fault. Geological and geophysical data indicate the presence of gabbro and peridotite over much of the corrugated central dome, inferred to be the footwall of a detachment fault. A vector magnetometer deployed 25m aft of the deeply towed side scan sonar system allowed measurement of both the total field and horizontal and vertical anomalous fields. Five profiles across the central dome reveal a lineated <span class="hlt">anomaly</span> low that was not evident in earlier sea surface profiles. The presence of lineated <span class="hlt">anomalies</span> over presumed gabbro and ultramafic exposures may record the acquisition of remanence as these rocks were exhumed by detachment faulting. <span class="hlt">Anomaly</span> profiles over the Lost City hydrothermal vent field exhibit a pronounced <span class="hlt">magnetic</span> low (reversed polarity), suggesting that active serpentinization is not responsible for the overall <span class="hlt">magnetization</span> pattern. When combined with results from planned IODP drilling at the site, these data should provide significant insights into the importance of gabbro and peridotite lithologies as sources for lineated <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">Gee, J.; Blackman, D.</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">262</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1512353E"> <span id="translatedtitle">Spatial Correlation of Airborne <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> with Reservoir Temperatures of Geothermal Fields, Western Anatolia, Turkey</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Geothermal areas in Western Anatolia are remarkably located throughout Büyük Menderes Graben (BMG) and Gediz Graben (GG). These E-W trending grabens have been subjected to N-E stretching since Miocene. Except for these major outcomes of the extensional forces, NE-SW oriented and relatively short grabens take place in Western Anatolia as well. Among them, BMG and GG are remarkable with topographic escarpments that reveal footwall of steeply-dipping active normal faults. They manifest themselves via numerous earthquakes and geothermal activity (fluid discharges from springs and wells). Geothermal discharges are aligned along the rims of E-W trending normal faults trending over detachment faults. Concerning BMG, geothermal manifestations extend along the northern sector of the graben. Geothermal reservoirs inside BMG are the limestone and conglomerate units within Neogene sediments and the marble-quartzite units within The Menderes Massif rocks. The main high and low enthalpy geothermal fields along BMG and their reservoir temperatures are as follows: K?z?ldere (242°C), Germencik (232°C), Ayd?n-Il?cabas? (101°C), Y?lmazköy (142°C), Salavatl? (171°C), Söke (26°C), Pamukkale (36°C), Karahay?t (59°C), Gölemezli (101°C) and Yenice (70°C). Through GG, reservoir temperatures decrease from east to west. Geothermal reservoirs inside GG are metamorphics and granodiorite of the Menderes Massif rocks. The Neogene sediments act as cap rock of the geothermal reservoirs. Geothermal fields inside the graben and their reservoir temperatures are as follows: Ala?ehir (215°C), Salihli (155°C), Urganl? (85°C), Kur?unlu (135°C), Caferbey (150°C), Sart (100°C). In order to investigate the spatial correlation of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and the reservoir temperatures of geothermal fields in the region, we analysed airborne <span class="hlt">magnetic</span> data which were collected by General Directorate of Mineral Research and Exploration (MTA) of Turkey. Airborne <span class="hlt">magnetic</span> data were taken at about 70-m intervals along the profiles and the profile interval was set as 1-2 km. Necessary corrections including the IGRF correction were carried out by MTA. After removing the horizontal planar trend and regional background, a reduction to the pole process was performed to residual <span class="hlt">magnetic</span> data. The pole reduced <span class="hlt">magnetic</span> intensity values vary in the range of -368 and 395 nT in the image map. In general, relatively high amplitude <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> zones indicate the geothermal fields having higher reservoir temperatures than 200°C in the region. On the other hand, moderate <span class="hlt">magnetic</span> intensity values point geothermal fields having lower reservoir temperatures than 200°C. It can be inferred that higher and moderate <span class="hlt">magnetic</span> intensity values in the region are positively and spatially in accordance with higher and lower geothermal reservoir temperatures relative to 200°C. Consequently, obtained results were discussed in terms of <span class="hlt">magnetic</span> intensity, geothermal heat source and geothermal reservoir temperatures. Keywords: <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span>, Reservoir Temperatures, Geothermal Fields, Western Anatolia, Turkey</p> <div class="credits"> <p class="dwt_author">Ertekin, Can; Ekinci, Yunus Levent</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">263</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009EGUGA..11.4046A"> <span id="translatedtitle">Edge detection of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> using analytic signal of tilt angle (ASTA)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary"><span class="hlt">Magnetic</span> is a commonly used geophysical technique to identify and image potential subsurface targets. Interpretation of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> is a complex process due to the superposition of multiple <span class="hlt">magnetic</span> sources, presence of geologic and cultural noise and acquisition and positioning error. Both the vertical and horizontal derivatives of potential field data are useful; horizontal derivative, enhance edges whereas vertical derivative narrow the width of <span class="hlt">anomaly</span> and so locate source bodies more accurately. We can combine vertical and horizontal derivative of <span class="hlt">magnetic</span> field to achieve analytic signal which is independent to body <span class="hlt">magnetization</span> direction and maximum value of this lies over edges of body directly. Tilt angle filter is phased-base filter and is defined as angle between vertical derivative and total horizontal derivative. Tilt angle value differ from +90 degree to -90 degree and its zero value lies over body edge. One of disadvantage of this filter is when encountering with deep sources the detected edge is blurred. For overcome this problem many authors introduced new filters such as total horizontal derivative of tilt angle or vertical derivative of tilt angle which Because of using high-order derivative in these filters results may be too noisy. If we combine analytic signal and tilt angle, a new filter termed (ASTA) is produced which its maximum value lies directly over body edge and is easer than tilt angle to delineate body edge and no complicity of tilt angle. In this work new filter has been demonstrated on <span class="hlt">magnetic</span> data from an area in Sar- Cheshme region in Iran. This area is located in 55 degree longitude and 32 degree latitude and is a copper potential region. The main formation in this area is Andesith and Trachyandezite. <span class="hlt">Magnetic</span> surveying was employed to separate the boundaries of Andezite and Trachyandezite from adjacent area. In this regard a variety of filters such as analytic signal, tilt angle and ASTA filter have been applied which new ASTA filter determined Andezite boundaries from surrounded more accurately than other filters. Keywords: Horizontal derivative, Vertical derivative, Tilt angle, Analytic signal, ASTA, Sar-Cheshme.</p> <div class="credits"> <p class="dwt_author">Alamdar, K.; Ansari, A. H.; Ghorbani, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">264</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..15.4407S"> <span id="translatedtitle">3D Geophysical Modelling of the Beattie <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> and Karoo Basin, South Africa</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Karoo Basin, the broad arid plateau that covers much of the interior of South Africa, is supported by the stable Archean Kaapvaal Craton in the north and several surrounding Proterozoic basement blocks in the south, and formed within the continental interior of Gondwana during the Late Carboniferous (300 Ma) to Middle Jurassic (125 Ma). No clear tectonic model exists for the Karoo Basin, with several hypotheses regarding the nature of the subsidence resulting in basin formation. To the southern edge of the Karoo basin the enigmatic Beattie <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> (BMA) is seen, which stretches east to west for ~1000 km across a large portion of South Africa, and for which a variety of explanations have been proposed. Here we present detailed 2D gravity and <span class="hlt">magnetic</span> models across the southwestern Karoo along with a combined first-order regional 3D model. The models presented here are based on seismic and potential field data, along with geological and structural information that cover the entire basin. Information about the Moho structure was derived from teleseismic data. The models have been further constrained using deep boreholes, as well as on- and off-shore seismic lines, Magnetotelluric data, and <span class="hlt">magnetic</span> depth-to-basement estimates. Density and susceptibility values are based on borehole and hand sample data, as well as on the conversion of p-wave seismic velocity to densities. In order to produce an accurate potential field model of the Karoo basin and to understand the evolution of the basin, a clear understanding is needed of the source of the Beattie. Seismic data over the western section of the Beattie <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> place the source in the mid-crust (10-15 km). Earlier studies have attributed the <span class="hlt">anomaly</span> to partially serpentinized oceanic lithosphere possibly linked to a suture zone, or to massive disseminate magnetite-sulphide bodies within the basement. However, our analysis lets us support the idea that the BMA is part of the tectono-metamorphic Namaqua-Natal Mobile Belt and associated shear zones.</p> <div class="credits"> <p class="dwt_author">Scheiber-Enslin, Stephanie; Ebbing, Jörg; Eberle, Detlef; Webb, Susan</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">265</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/897563"> <span id="translatedtitle"><span class="hlt">Magnetization</span> <span class="hlt">anomaly</span> of Nb3Al strands and instability of Nb3Al Rutherford cables</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Using a Cu stabilized Nb{sub 3}Al strand with Nb matrix, a 30 meter long Nb{sub 3}Al Rutherford cable was made by a collaboration of Fermilab and NIMS. Recently the strand and cable were tested. In both cases instability was observed at around 1.5 Tesla. The <span class="hlt">magnetization</span> of this Nb{sub 3}Al strand was measured first using a balanced coil magnetometer at 4.2 K. Strands showed an anomalously large <span class="hlt">magnetization</span> behavior around at 1.6 T, which is much higher than the usual B{sub c2} {approx} 0.5 Tesla (4.2 K) of Nb matrix. This result is compared with the <span class="hlt">magnetization</span> data of short strand samples using a SQUID magnetometer, in which a flux-jump signal was observed at 0.5 Tesla, but not at higher field. As a possible explanation for this <span class="hlt">magnetization</span> <span class="hlt">anomaly</span>, the interfilament coupling through the thin Nb films in the strands is suggested. The instability problem observed in low field tests of the Nb{sub 3}Al Rutherford cables is attributed to this effect.</p> <div class="credits"> <p class="dwt_author">Yamada, Ryuji; /Fermilab; Kikuchi, Akihiro; /Tsukuba Magnet Lab; Wake, Masayoshi; /KEK, Tsukuba</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">266</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013Tectp.585..113G"> <span id="translatedtitle">Deciphering tectonic phases of the Amundsen Sea Embayment shelf, West Antarctica, from a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> grid</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Amundsen Sea Embayment (ASE), with Pine Island Bay (PIB) in the eastern embayment, is a key location to understanding tectonic processes of the Pacific margin of West Antarctica. PIB has for a long time been suggested to contain the crustal boundary between the Thurston Island block and the Marie Byrd Land block. Plate tectonic reconstructions have shown that the initial rifting and breakup of New Zealand from West Antarctica occurred between Chatham Rise and the eastern Marie Byrd Land at the ASE. Recent concepts have discussed the possibility of PIB being the site of one of the eastern branches of the West Antarctic Rift System (WARS). About 30,000 km of aeromagnetic data - collected opportunistically by ship-based helicopter flights - and tracks of ship-borne <span class="hlt">magnetics</span> were recorded over the ASE shelf during two RV Polarstern expeditions in 2006 and 2010. Grid processing, Euler deconvolution and 2D modelling were applied for the analysis of <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> patterns, identification of structural lineaments and characterisation of <span class="hlt">magnetic</span> source bodies. The grid clearly outlines the boundary zone between the inner shelf with outcropping basement rocks and the sedimentary basins of the middle to outer shelf. Distinct zones of <span class="hlt">anomaly</span> patterns and lineaments can be associated with at least three tectonic phases from (1) magmatic emplacement zones of Cretaceous rifting and breakup (100-85 Ma), to (2) a southern distributed plate boundary zone of the Bellingshausen Plate (80-61 Ma) and (3) activities of the WARS indicated by NNE-SSW trending lineaments (55-30 Ma?). The analysis and interpretation are also used for constraining the directions of some of the flow paths of past grounded ice streams across the shelf.</p> <div class="credits"> <p class="dwt_author">Gohl, Karsten; Denk, Astrid; Eagles, Graeme; Wobbe, Florian</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">267</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20110023400&hterms=alpine&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dalpine"> <span id="translatedtitle">Investigation of the Crust of the Pannonian Basin, Hungary Using Low-Altitude CHAMP Horizontal Gradient <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The Pannonian Basin is a deep intra-continental basin that formed as part of the Alpine orogeny. It is some 600 by 500 km in area and centered on Hungary. This area was chosen since it has one of the thinnest continental crusts in Europe and is the region of complex tectonic structures. In order to study the nature of the crustal basement we used the long-wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> acquired by the CHAMP satellite. The SWARM constellation, scheduled to be launched next year, will have two lower altitude satellites flying abreast, with a separation of between ca. 150 to 200 km. to record the horizontal <span class="hlt">magnetic</span> gradient. Since the CHAMP satellite has been in orbit for eight years and has obtained an extensive range of data, both vertically and horizontally there is a large enough data base to compute the horizontal <span class="hlt">magnetic</span> gradients over the Pannonian Basin region using these many CHAMP orbits. We recomputed a satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map, using the spherical-cap method of Haines (1985), the technique of Alsdorf et al. (1994) and from spherical harmonic coefficients of MF6 (Maus et aI., 2008) employing the latest and lowest altitude CHAMP data. We then computed the horizontal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> gradients (Kis and Puszta, 2006) in order to determine how these component data will improve our interpretation and to preview what the SW ARM mission will reveal with reference to the horizontal gradient <span class="hlt">anomalies</span>. The gradient amplitude of an 1000 km northeast-southwest profile through our horizontal component <span class="hlt">anomaly</span> map varied from 0 to 0.025 nT/km with twin positive <span class="hlt">anomalies</span> (0.025 and 0.023 nT/km) separated by a sharp <span class="hlt">anomaly</span> negative at o nT/km. Horizontal gradient indicate major <span class="hlt">magnetization</span> boundaries in the crust (Dole and Jordan, 1978 and Cordell and Grauch, 1985). Our gradient <span class="hlt">anomaly</span> was modeled with a twodimensional body and the <span class="hlt">anomaly</span>, of some 200 km, correlates with a 200 km area of crustal thinning in the southwestern Pannonian Basin.</p> <div class="credits"> <p class="dwt_author">Taylor, Patrick T.; Kis, Karoly I.; Puszta, Sandor; Wittmann, Geza; Kim, Hyung Rae; Toronyi, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">268</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFMGP21A0987T"> <span id="translatedtitle">Investigation of the crust of the Pannonian Basin, Hungary using low-altitude CHAMP horizontal <span class="hlt">magnetic</span> gradient <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Pannonian Basin is a deep intracontinental basin that formed as part of the Alpine orogeny. It is some 600 by 500 km in area and centered on Hungary. This region was chosen since it has one of the thinnest continental crusts in Europe and is the location of complex tectonic structures. In order to study the nature of the crustal basement we used the long-wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> acquired by the CHAMP satellite. The SWARM constellation, scheduled to be launched next year, will have two lower altitude satellites flying abreast, with a separation of between ca. 150 to 200 km. to record the horizontal <span class="hlt">magnetic</span> gradient. Since the CHAMP satellite has been in orbit for eight years and has obtained an extensive range of data, both vertically and horizontally there is a large enough data base to compute the horizontal <span class="hlt">magnetic</span> gradients over the Pannonian Basin region using these many CHAMP orbits. We computed a satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> map, using the spherical-cap method of Haines (1985), the technique of Alsdorf et al. (1994) and from spherical harmonic coefficients of MF6 (Maus et al., 2008) employing recent and lowest altitude CHAMP data. We then computed the horizontal <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> gradients (Kis and Puszta, 2006) in order to determine how these component data will improve our interpretation and to preview what the SWARM mission will reveal with reference to the horizontal gradient <span class="hlt">anomalies</span>. The gradient amplitude of an 1000 km northeast-southwest profile through our horizontal component <span class="hlt">anomaly</span> map varied from 0 to 0.025 nT/km with twin positive <span class="hlt">anomalies</span> (0.025 and 0.023 nT/km) separated by a sharp V-shaped <span class="hlt">anomaly</span> gradient to 0 nT/km between the two highs. Horizontal gradients indicate major <span class="hlt">magnetization</span> boundaries in the crust (Dole and Jordan, 1978 and Cordell and Grauch, 1985). Our gradient <span class="hlt">anomaly</span> was modeled with a two-dimensional body and this <span class="hlt">anomaly</span> indicates a lateral variation of some 200 km. The model correlates with a 200 km area of crustal thinning in the southwestern Pannonian Basin.</p> <div class="credits"> <p class="dwt_author">Taylor, P. T.; Kis, K. I.; Puszta, S.; Wittman, G.; Kim, H.; Toronyi, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">269</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011DokES.436..117T"> <span id="translatedtitle">Extraction of the <span class="hlt">anomaly</span> <span class="hlt">magnetic</span> field of the earth from stratospheric balloon <span class="hlt">magnetic</span> surveys at altitudes of 20-40 km</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The solution to the problem of extraction of the <span class="hlt">anomaly</span> Earth's <span class="hlt">magnetic</span> field (EMF) from stratospheric balloon <span class="hlt">magnetic</span> surveys with the help of global analytical models of the normal EMF is proposed. In the problem solution, errors for the analytical models of the normal EMF and its secular variation at a set moment of time are assessed; the found error is introduced as a correction to the extracted <span class="hlt">anomaly</span> EMF. The error of the model is determined in the places where significant <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are absent. In this case, the error of the model corresponds to deviations of the normal EMF components, synthesized by coefficients of analytical models, and to deviations of the EMF secular variations from the measured values at quite a low value of the variable EMF or one being taken into account. These places are determined when carrying out additional measurements in vertical gradients of the EMF with the use of scalar magnetometers at the gauge length of 6 km. It has been shown that the found places can be considered as nonanomaly, if the difference of values of the <span class="hlt">anomaly</span> EMF at the gauge length of 6 km does not exceed 1.5 nT within the profile's portion of about 100 km in length. An experiment in nature has revealed that errors for the IGRF-2005 and IGRF-2010 models, corrected for secular variation of the EMF, can reach 200 and 140 nT, respectively, within the limits of the territory where the Kama-Emba <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is located; these errors are determined by the considered causes. Comparison of aerostatic profiles of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> with data on the <span class="hlt">anomaly</span> EMF, derived from the maps, has shown that the realizations derived from the maps contain overestimated negative values of the <span class="hlt">anomaly</span> EMF, because they reflect processes in the near-surface layer of the Earth's crust. This fact causes the situation when attempts to recalculate the <span class="hlt">anomaly</span> EMF into the upper half-space by the near-surface data still have not been successful. Only realizations derived at the altitudes comparable to the thickness of the Earth's crust can give an adequate model of the <span class="hlt">anomaly</span> EMF in the circumterrestrial space and enable us to recalculate <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> reliably into any altitude levels.</p> <div class="credits"> <p class="dwt_author">Tsvetkov, Yu. P.; Kuznetsov, V. D.; Golovkov, V. P.; Brekhov, O. M.; Pelle, V. A.; Krapivnyi, A. V.; Nikolaev, N. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">270</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005JGRB..11012102B"> <span id="translatedtitle">Paleomagnetic determinations on Lanzarote from <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span>: Implications for the early history of the Canary Islands</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Bouguer and aeromagnetic <span class="hlt">anomaly</span> maps of Lanzarote show a gravity high and a dipolar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> over the central part of the island, indicating one isolated source. Assuming that the structure responsible for both <span class="hlt">anomalies</span> is the same, a methodology has been designed to estimate the total <span class="hlt">magnetization</span> vector of the source, which is interpreted as a large intrusive body (mafic core) positioned as a result of magma rising to the surface during the early stages of growth of Lanzarote. Considering its geometry to be known from a previous three-dimensional (3-D) gravity model, the approach proposed in this paper is based on the delineation of <span class="hlt">magnetic</span> contacts through analysis of the horizontal gradient of the reduced-to-the-pole <span class="hlt">anomaly</span> map, comparison between the gravity and the pseudogravity <span class="hlt">anomalies</span>, and 3-D forward <span class="hlt">magnetic</span> modeling. The total <span class="hlt">magnetization</span> vector obtained by this method is defined by a module of 4.5 A m-1 and a direction D = -20° and I = 30°. Comparing the paleomagnetic pole, obtained from this direction, with the apparent polar wander path of Africa for the last 160 Myr, it is concluded that the main component of the total <span class="hlt">magnetization</span> vector is probably a primary natural remanent <span class="hlt">magnetization</span> (NRM) which could have been acquired between 60 and 100 Ma. This result suggests that the emplacement of magmas at shallow depths linked to the beginning of volcanism in Lanzarote took place during the Upper Cretaceous, thus providing the first evidence of a timeline for the early formative stages of this volcanic island.</p> <div class="credits"> <p class="dwt_author">Blanco-Montenegro, I.; Montesinos, F. G.; GarcíA, A.; Vieira, R.; VillalaíN, J. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">271</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://siogeoscience.ucsd.edu/publications/pdfs/grindlayetalepsl1998.pdf"> <span id="translatedtitle">A different pattern of ridge segmentation and mantle Bouguer gravity <span class="hlt">anomalies</span> along the ultra-slow <span class="hlt">spreading</span> Southwest Indian Ridge (15º300E to 25ºE)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The results of a recent bathymetric and geophysical investigation of a650 km-long portion of the very slowly opening (16 mm=yr full rate) Southwest Indian Ridge (SWIR) between 15º300E and 25ºE are presented. Bathymetry and mantle Bouguer gravity <span class="hlt">anomalies</span> (MBA), caused by variations in crustal thickness and=or crustal and upper mantle densities, show different characteristics from those observed at faster <span class="hlt">spreading</span></p> <div class="credits"> <p class="dwt_author">Nancy R. Grindlay; John A. Madsen; Celine Rommevaux-Jestin; John Sclater</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">272</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP34A..04M"> <span id="translatedtitle">Remanent and Induced <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> over the Bjerkreim-Sokndal Layered Intrusion: Effects from Crystal Fractionation and Magma Recharge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Bjerkreim-Sokndal (BKS) norite-quartz mangerite layered intrusion is part of the early Neoproterozoic Rogaland Anorthosite Province intruded into the Fennoscandian shield in south Norway at ~930 Ma. The BKS is exposed over an area of 230 km2 with a thickness of ~7000m and is of economic interest for hemo-ilmenite, magnetite and apatite deposits. From the point of view of <span class="hlt">magnetic</span> minerals, in the course of fractional crystallization and magma evolution, the ilmenite becomes less Fe3+-rich reflected by a change from ilmenite with hematite exsolution to nearly pure ilmenite. Magnetite starts to crystallize relatively late in the intrusive history, but its crystallization is interrupted by influxes of more primitive magma containing hemo-ilmenite. The variations in aeromagnetic and ground-<span class="hlt">magnetic</span> <span class="hlt">anomalies</span> measured over the BKS can be explained in terms of the <span class="hlt">magnetic</span> properties of NRM, susceptibility, and hysteresis. <span class="hlt">Magnetic</span> properties are correlated with the oxide mineralogy and mineral chemistry. Early layers in the intrusion contain hemo-ilmenite. As the magma evolved and magnetite started to crystallize, this caused a distinct change over the layering from remanence-controlled negative <span class="hlt">anomalies</span> to induced positive <span class="hlt">anomalies</span>. When new, more primitive magma was injected into the system, hemo-ilmenite returned as the major oxide and the resulting <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are again negative. The most dramatic change in the <span class="hlt">magnetic</span> signature is in the upper part of the intrusion in MCU IVe, where magnetite became a well established cumulate phase as indicated by susceptibility, but its induced <span class="hlt">magnetization</span> is overcome by large NRM's associated either with hemo-ilmenite or with hemo-ilmenite and magnetite exsolved from pyroxenes. The average natural remanent <span class="hlt">magnetizations</span> change from ~3 A/m in MCU IVd, to 15 A/m in MCU IVe, and back to 2 A/m in the overlying MCU IVf, producing a strong negative remanent <span class="hlt">anomaly</span> that has been followed along strike for at least 20 km by ground-<span class="hlt">magnetic</span> measurements. The highly varied <span class="hlt">magnetic</span> properties of this intrusion, caused by varied magmatic crystallization of combinations of oxide minerals illustrate some of the possibilities to be considered in evaluating crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</p> <div class="credits"> <p class="dwt_author">McEnroe, S. A.; Brown, L. L.; Robinson, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">273</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/24785022"> <span id="translatedtitle">Electromagnetic particle-in-cell simulations of the solar wind interaction with lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">We present the first three-dimensional fully kinetic and electromagnetic simulations of the solar wind interaction with lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> (LMAs). Using the implicit particle-in-cell code iPic3D, we confirm that LMAs may indeed be strong enough to stand off the solar wind from directly impacting the lunar surface forming a mini-magnetosphere, as suggested by spacecraft observations and theory. In contrast to earlier magnetohydrodynamics and hybrid simulations, the fully kinetic nature of iPic3D allows us to investigate the space charge effects and in particular the electron dynamics dominating the near-surface lunar plasma environment. We describe for the first time the interaction of a dipole model centered just below the lunar surface under plasma conditions such that only the electron population is <span class="hlt">magnetized</span>. The fully kinetic treatment identifies electromagnetic modes that alter the <span class="hlt">magnetic</span> field at scales determined by the electron physics. Driven by strong pressure anisotropies, the mini-magnetosphere is unstable over time, leading to only temporal shielding of the surface underneath. Future human exploration as well as lunar science in general therefore hinges on a better understanding of LMAs. PMID:24785022</p> <div class="credits"> <p class="dwt_author">Deca, J; Divin, A; Lapenta, G; Lembège, B; Markidis, S; Horányi, M</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-04-18</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">274</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014PhRvL.112o1102D"> <span id="translatedtitle">Electromagnetic Particle-in-Cell Simulations of the Solar Wind Interaction with Lunar <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present the first three-dimensional fully kinetic and electromagnetic simulations of the solar wind interaction with lunar crustal <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> (LMAs). Using the implicit particle-in-cell code iPic3D, we confirm that LMAs may indeed be strong enough to stand off the solar wind from directly impacting the lunar surface forming a mini-magnetosphere, as suggested by spacecraft observations and theory. In contrast to earlier magnetohydrodynamics and hybrid simulations, the fully kinetic nature of iPic3D allows us to investigate the space charge effects and in particular the electron dynamics dominating the near-surface lunar plasma environment. We describe for the first time the interaction of a dipole model centered just below the lunar surface under plasma conditions such that only the electron population is <span class="hlt">magnetized</span>. The fully kinetic treatment identifies electromagnetic modes that alter the <span class="hlt">magnetic</span> field at scales determined by the electron physics. Driven by strong pressure anisotropies, the mini-magnetosphere is unstable over time, leading to only temporal shielding of the surface underneath. Future human exploration as well as lunar science in general therefore hinges on a better understanding of LMAs.</p> <div class="credits"> <p class="dwt_author">Deca, J.; Divin, A.; Lapenta, G.; Lembège, B.; Markidis, S.; Horányi, M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-04-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">275</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFMNS13A1075B"> <span id="translatedtitle">Estimation of bedrock lithology concealed by basin sediment fill using <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Many undiscovered mineral deposits in the U.S. are likely to be found in bedrock concealed beneath shallow basin fill sediments. A technique has been developed to estimate concealed bedrock lithology (at less than about 250m depth) in some cases by matching the texture (physical appearance or character) of plotted Earth's total <span class="hlt">magnetic</span> field <span class="hlt">anomaly</span> profile data acquired over basin fill with that of similar data acquired over nearby exposed bedrock lithology. The data are acquired using a truck-mounted cesium vapor magnetometer at 4m height and at measurement intervals as small as 1m. Data are acquired over basin fill and over several exposed candidate lithologies adjacent to the basin. Data over exposed candidate lithologies are then upward continued to the estimated depth of burial of the concealed bedrock lithology. <span class="hlt">Magnetic</span> data representing just the basin fill (from a deep portion of the basin) are added to those data. Several statistical and fractal measures are then used to create a quantitative <span class="hlt">magnetic</span> signature of both the mapped candidate lithologies and the concealed bedrock lithologies. These measures are compared by several techniques, sometimes including principal components analysis, to make a final interpretation. This technique was successfully applied in the San Rafael basin, southeastern Arizona, which is adjacent to several exposed mineral deposits.</p> <div class="credits"> <p class="dwt_author">Bultman, M. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">276</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFMNS13B1617O"> <span id="translatedtitle">Geophysical Surveying of Shallow <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Using the iPhone Magnetometer</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">This investigation examined whether the 3-axis Hall-effect magnetometer in the Apple iPhone 3GS can function as an effective shallow <span class="hlt">magnetic</span> survey instrument. The xSensor Pro app from Crossbow Systems allows recoding of all three sensor components along with the GPS location, at a frequency of 1.0, 4.0, 16.0, and 32.0 Hz. If the iPhone proves successful in collecting useful <span class="hlt">magnetic</span> data, then geophysicists and especially educators would have a new tool for high-density geophysical mapping. No-contract iPhones that can connect with WiFi can be obtained for about $400, allowing deployment of large numbers of instruments. iPhones with the xSensor Pro app surveyed in parallel with an Overhauser GEM system magnetometer (1 nT sensitivity) to test this idea. Anderson Bay, located on the Pyramid Lake Paiute Reservation, provided a rural survey location free from cultural interference. xSensor Pro, logged each component's intensity and the GPS location at a frequency of four measurements per second. Two Overhauser units functioned as a base unit and a roving unit. The roving unit collected total field at set points located with a handheld GPS. Comparing the total field computed from the iPhone components against that collected by the Overhauser establishes the level of <span class="hlt">anomalies</span> that the iPhone can detect. iPhone total-field measurements commonly vary by 200 nT from point to point, so a spatial-temporal average over 25 seconds produces a smoothed signal for comparison. Preliminary analysis of the iPhone results show that the data do not accurately correlate to the total field collected by the Overhauser for any <span class="hlt">anomaly</span> of less than 200 nT.</p> <div class="credits"> <p class="dwt_author">Opdyke, P.; Dudley, C.; Louie, J. N.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">277</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE83009138"> <span id="translatedtitle">Analysis of the Nuevo Leon <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> and Its Possible Relation to the Cerro Prieto Magmatic-Hydrothermal System.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The broad dipolar <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> whose positive peak is centered near Ejido Nuevo Leon, some 5 km east of the Cerro Prieto I Power Plant, has long been suspected to have a genetic relationship to the thermal source of the Cerro Prieto geothermal system....</p> <div class="credits"> <p class="dwt_author">N. E. Goldstein M. J. Wilt D. J. Corrigan</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">278</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=AD655698"> <span id="translatedtitle">On Relation of <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> to the Structure of the Earth Crust in the Southeastern Part of Central Kazakhstan.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Lately there are attempts to utilize the data of the aeromagnetic survey in the study of both the abyssal structure of the earth's crust and the structure of its upper stratified horizons. In order to explain the relations between <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of di...</p> <div class="credits"> <p class="dwt_author">L. I. Puchkova A. V. Ladynin</p> <p class="dwt_publisher"></p> <p class="publishDate">1967-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">279</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18313413"> <span id="translatedtitle">Resistive and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the Bi-Sr-V-O and Tl-Sr-V-O compound systems</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Resistive drops and apparent DC ``diamagnetic'' shifts at temperatures up to 150 K, usually suggestive of a superconductive transition, have been observed in the reduced SrVO3-delta system doped with Bi and Tl. Unfortunately, detailed examinations reveal that such <span class="hlt">anomalies</span> are <span class="hlt">magnetic</span> in Origin. It is, therefore, concluded that the exosting results of either Hitachi of Houston are not sufficient for</p> <div class="credits"> <p class="dwt_author">Z. J. Huang; Y. Q. Wang; Y. Y. Sun; R. L. Meng; J. W. Chu; L. Gao; J. Bechtold; H. H. Feng; Y. Y. Xue; P. H. Hor; C. W. Chu</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">280</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012JGRE..11710007M"> <span id="translatedtitle">The history of Mars' dynamo as revealed by modeling <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> near Tyrrhenus Mons and Syrtis Major</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The lack of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> within the major impact basins (Hellas, Argyre, and Isidis) has led many investigators to the conclusion that Mars' dynamo shut down prior to the time when these basins formed (˜4.0 Ga). We test this hypothesis by analyzing gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the regions surrounding Tyrrhenus Mons and Syrtis Major, two volcanoes that were active during the late Noachian and Hesperian. We model <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> that are associated with gravity <span class="hlt">anomalies</span> and generally find that sources located below Noachian surface units tend to favor paleopoles near the equator and sources located below Hesperian surface features favor paleopoles near the geographical poles, suggesting polar wander during the Noachian-Hesperian. Both paleopole clusters have positive and negative polarities, indicating reversals of the field during the Noachian and Hesperian. <span class="hlt">Magnetization</span> of sources below Hesperian surfaces is evidence that the dynamo persisted beyond the formation of the major impact basins. The demagnetization associated with the volcanic construct of Syrtis Major implies dynamo cessation occurred while it was geologically active approximately 3.6 billion years ago. Timing of dynamo activity is fundamentally linked to Mars' climate via the stability of its atmosphere, and is coupled to the extent and duration of surface geologic activity. Thus, the dynamo history is key for understanding both when Mars was most geologically active and when it may have been most hospitable to life.</p> <div class="credits"> <p class="dwt_author">Milbury, C.; Schubert, G.; Raymond, C. A.; Smrekar, S. E.; Langlais, B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_13");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return 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id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' href="#">4</a> <a onClick='return showDiv("page_5");' href="#">5</a> <a onClick='return showDiv("page_6");' href="#">6</a> <a onClick='return showDiv("page_7");' href="#">7</a> <a onClick='return showDiv("page_8");' href="#">8</a> <a onClick='return showDiv("page_9");' href="#">9</a> <a onClick='return showDiv("page_10");' href="#">10</a> <a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a style="font-weight: bold;">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a onClick='return showDiv("page_18");' href="#">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_16");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">281</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52795006"> <span id="translatedtitle">Three-Dimensional Mapping of <span class="hlt">Magnetic</span> Strata From Aeromagnetic <span class="hlt">Anomalies</span>: The Deformed Neroly Formation South of Mt. Diablo, Northern California</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We apply direct inversion of aeromagnetic <span class="hlt">anomalies</span> to analyze the subsurface 3D shape of the highly <span class="hlt">magnetic</span> Miocene Neroly Formation, which consists largely of medium to coarse-grained andesitic sandstones containing abundant magnetite. The Neroly Formation is widespread in the eastern San Francisco Bay region, and locally is tightly folded and disrupted by faulting in the compressional regime related to the</p> <div class="credits"> <p class="dwt_author">R. C. Jachens; R. W. Simpson; R. W. Graymer; C. M. Wentworth</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">282</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T42B..06L"> <span id="translatedtitle">A possible 90 - 100 MYBP <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in the western-most Philippine Sea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">10 years ago, Tamaki's team offered the deep-towed magnetometer and my team provided the R/V Ocean Research No. 1. We jointly conducted a deep-towed <span class="hlt">magnetic</span> survey in the western-most Philippine Sea (also called the Huatung Basin). The results show the <span class="hlt">magnetic</span> age could be either as the previous reported 35- 45 MYBP or as the ambiguous 90 - 100 MYBP. 10 year later, a Taiwan-USA co-operation on the understanding of Taiwan Mountain Building processes (the TAIGER project) has shown that this area and the east contain a huge area of submarine volcanoes and at least in 4-5 regions showing the overlapping <span class="hlt">spreading</span> ridges, similar like today's East Pacific <span class="hlt">Spreading</span> Center of higher <span class="hlt">spreading</span> rate. This is interpreted as the 45 MYBP when the Pacific Plate changed its motion from N to NW and the massive volcanic activity accompany the motion change. Before the change, it is possible to have the Kula Plate in the east and the Tethys Sea in the west crossing the Pacific and Indian oceans at about 90 - 100 MYBP. The Taiwan Central Range and China Fuzhian Massive Range support this idea. At about 45 - 65 MYBP, the Himalaya and Alps experienced the head-to-head collision and the mountains started to push up. In the mean time, the Kula Plate disappeared and the Tethys Sea diminished its size. These could trigger the Western Pacific trench-arc-backarc systems. The systems continue to evolve up to today. The Gagua Ridge, located along the E longitude 123 degree, act as a dam to prevent the sediment further deposits into the east side of the Philippine Sea. The new OBS refraction and earthquake data show the east side of the Philippine Sea is subducting into the west side, the western-most Philippine Sea. The previous <span class="hlt">magnetic</span> lineation, fossil radiolarian and metamorphosed igneous ages found surround the basin support that the western-most Philippine Sea may be the last remaining Tethys Sea in the Pacific.</p> <div class="credits"> <p class="dwt_author">Lee, C.; Cho, Y.; Liang, C.; Lai, W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">283</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008JGeo...45..217R"> <span id="translatedtitle">Age of the source of the Jarrafa gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> offshore Libya and its geodynamic implications</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The interpretation of the Jarrafa <span class="hlt">magnetic</span> and gravity highs, NW Libyan offshore, suggests that it may be caused by a body of high-density and high <span class="hlt">magnetization</span>. Analysis of their power spectra indicates two groups of sources at: (1) 2.7 km depth, probably related to the igneous rocks, some of which were penetrated in the JA-1 borehole, (2) 5 km depth, corresponding to the top of the causative body and (3) 10 km depth, probably referring to the local basement depth. The boundary analysis derived from applied horizontal gradient to both gravity and <span class="hlt">magnetic</span> data reveals lineaments many of which can be related to geological structures (grabens, horsts and faults). The poor correlation between pseudogravity fields for induced <span class="hlt">magnetization</span> and observed gravity fields strongly suggests that the causative structure has a remanent <span class="hlt">magnetization</span> ( D = -16°, I = 23°) of Early Cretaceous age, fitting with the opening of the Neo Tethys 3 Ocean. Three-dimensional interpretation techniques indicate that the <span class="hlt">magnetic</span> source of the Jarrafa <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> has a <span class="hlt">magnetization</span> intensity of 0.46 A/m, which is required to simulate the amplitude of the observed <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. The <span class="hlt">magnetic</span> model shows that it has a base level at 15 km. The history of the area combined with the analysis and interpretation of the gravity and <span class="hlt">magnetic</span> data suggests that: (1) the source of the Jarrafa <span class="hlt">anomaly</span> is a mafic igneous rock and it may have formed during an Early Cretaceous extensional phase and (2) the Jarrafa basin was left-laterally sheared along the WNW Hercynian North Graben Fault Zone, during its reactivation in the Early Cretaceous.</p> <div class="credits"> <p class="dwt_author">Reeh, Giuma; Aïfa, Tahar</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">284</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940016195&hterms=radiometric+dating&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dradiometric%2Bdating"> <span id="translatedtitle">Modelling the gravity and <span class="hlt">magnetic</span> field <span class="hlt">anomalies</span> of the Chicxulub crater</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The approximately 180-km-diameter Chicxulub crater lies buried by approximately 1 km of sediment on the northwestern corner of the Yucatan Peninsula, Mexico. Geophysical, stratigraphic and petrologic evidence support an impact origin for the structure and biostratigraphy suggests that a K/T age is possible for the impact. The crater's location is in agreement with constraints derived from proximal K/T impact-wave and ejecta deposits and its melt-rock is similar in composition to the K/T tektites. Radiometric dating of the melt rock reveals an age identical to that of the K/T tektites. The impact which produced the Chicxulub crater probably produced the K/T extinctions and understanding the now-buried crater will provide constraints on the impact's lethal effects. The outstanding preservation of the crater, the availability of detailed gravity and <span class="hlt">magnetic</span> data sets, and the two-component target of carbonate/evaporites overlying silicate basement allow application of geophysical modeling techniques to explore the crater under most favorable circumstances. We have found that the main features of the gravity and <span class="hlt">magnetic</span> field <span class="hlt">anomalies</span> may be produced by the crater lithologies.</p> <div class="credits"> <p class="dwt_author">Aleman, C. Ortiz; Pilkington, M.; Hildebrand, A. R.; Roest, W. R.; Grieve, R. A. F.; Keating, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">1993-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">285</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20110013498&hterms=sarah&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsarah"> <span id="translatedtitle">Characterization of Lunar Swirls at Mare Ingenii: A Model for Space Weathering at <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Analysis of spectra from the Clementine ultraviolet-visible and near-infrared cameras of small, immature craters and surface soils both on and adjacent to the lunar swirls at Marc Ingenii has yielded the following conclusions about space weathering at a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. (l) Despite having spectral characteristics of immaturity, the lunar swirls arc not freshly exposed surfaces. (2) The swirl surfaces arc regions of retarded weathering, while immediately adjacent regions experience accelerated weathering, (3) Weathering in the off-swirl regions darkens and flattens the spectrum with little to no reddening, which suggests that the production of larger (greater than 40 nm) nanophase iron dominates in these locations as a result of charged particle sorting by the <span class="hlt">magnetic</span> field. Preliminaty analysis of two other lunar swirl regions, Reiner Gamma and Mare Marginis, is consistent with our observations at Mare Ingenii. Our results indicate that sputtering/vapor deposition, implanted solar wind hydrogen, and agglutination share responsibility for creating the range in npFe(sup 0) particle sizes responsible for the spectral effects of space weathering.</p> <div class="credits"> <p class="dwt_author">Kramer, Georgianna Y.; Combe, Jean-Philippe; Harnett, Erika M.; Hawke, Bernard Ray; Noble, Sarah K.; Blewett, David T.; McCord, Thomas B.; Giguere, Thomas A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">286</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AnGeo..31.1833F"> <span id="translatedtitle">Evidence for cosmic ray modulation in temperature records from the South Atlantic <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> region</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Possible direct or indirect climatic effects related to solar variability and El Niño-Southern Oscillation (ENSO) were investigated in the southern Brazil region by means of the annual mean temperatures from four weather stations 2 degrees of latitude apart over the South Atlantic <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (SAMA) region. Four maximum temperature peaks are evident at all stations in 1940, 1958, 1977 and 2002. A spectral analysis indicates the occurrence of periodicities between 2 and 7 yr, most likely associated with ENSO, and periodicities of approximately 11 and 22 yr, normally associated with solar variability. Cross-wavelet analysis indicated that the signal associated with the 22 yr solar <span class="hlt">magnetic</span> cycle was more persistent in the last decades, while the 11 yr sunspot cycle and ENSO periodicities were intermittent. Phase-angle analysis revealed that temperature variations and the 22 yr solar cycle were in anti-phase near the SAMA center. Results show an indirect indication of possible relationships between the variability of galactic cosmic rays and climate change on a regional scale.</p> <div class="credits"> <p class="dwt_author">Frigo, E.; Pacca, I. G.; Pereira-Filho, A. J.; Rampelloto, P. H.; Rigozo, N. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">287</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007CG.....33..966S"> <span id="translatedtitle">Use of Walsh transforms in estimation of depths of idealized sources from total-field <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We developed a scheme to compute the depths of four idealized <span class="hlt">magnetized</span> sources, viz., a monopole, a line of monopoles, a dipole and a line of dipoles from the Walsh spectra of the total-field <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. The sequency numbers, lmax corresponding to the peaks of the differential energy density spectra over these sources are practically independent of the shape of the observed <span class="hlt">anomaly</span> and are linearly dependent on the source depths. For each model, we derived a quantitative relation between the depth and the sequency number lmax. Analyses of simulated data over idealized isolated sources reveal that (i) a profile length of about 8 times the source depth provides accurate value in computed depth; (ii) data spacing of less than one-fourth the source depth has no significant error in depth computation and (iii) the technique is capable of tolerating random error to the tune of 10% of the peak amplitude of the simulated <span class="hlt">anomaly</span>. We compared the results of depth estimations from Walsh and Fourier spectra. Analysis of total-field <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over a buried water supply pipe has demonstrated the applicability of the proposed method.</p> <div class="credits"> <p class="dwt_author">Shaw, Ranjit K.; Agarwal, B. N. P.; Nandi, B. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">288</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMSM21B2175D"> <span id="translatedtitle">3D Electromagnetic Particle-in-Cell simulations of the solar wind interaction with lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Unlike the Earth and Mercury, our Moon has no global <span class="hlt">magnetic</span> field and is therefore not shielded from the impinging solar wind by a magnetosphere. However, lunar <span class="hlt">magnetic</span> field measurements made by the Apollo missions provided direct evidence that the Moon has regions of small-scale crustal <span class="hlt">magnetic</span> fields, ranging up to a few 100km in scale size with surface <span class="hlt">magnetic</span> field strengths up to hundreds of nanoTeslas. More recently, the Lunar Prospector spacecraft has provided high-resolution observations allowing to construct <span class="hlt">magnetic</span> field maps of the entire Moon, confirming the earlier results from Apollo, but also showing that the lunar plasma environment is much richer than earlier believed. Typically the small-scale <span class="hlt">magnetic</span> fields are non-dipolar and rather tiny compared to the lunar radius and mainly clustered on the far side of the moon. Using iPic3D we present the first 3D fully kinetic and electromagnetic Particle-in-Cell simulations of the solar wind interaction with lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. We study the behaviour of a dipole model with variable surface <span class="hlt">magnetic</span> field strength under changing solar wind conditions and confirm that lunar crustal <span class="hlt">magnetic</span> fields may indeed be strong enough to stand off the solar wind and form a mini-magnetosphere, as suggested by MHD and hybrid simulations and spacecraft observations. 3D-PIC simulations reveal to be very helpful to analyze the diversion/braking of the particle flux and the characteristics of the resulting particles accumulation. The particle flux to the surface is significantly reduced at the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, surrounded by a region of enhanced density due to the <span class="hlt">magnetic</span> mirror effect. Second, the ability of iPic3D to resolve all plasma components (heavy ions, protons and electrons) allows to discuss in detail the electron physics leading to the highly non-adiabatic interactions expected as well as the implications for solar wind shielding of the lunar surface, depending on the scale size (solar wind protons typically have gyroradii larger than the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> scale size) and <span class="hlt">magnetic</span> field strength. The research leading to these results has received funding from the European Commission's Seventh Framework Programme (FP7/2007-2013) under the grant agreement SWIFF (project 2633430, swiff.eu). Cut along the dipole axis of the lunar <span class="hlt">anomaly</span>, showing the electron density structure.</p> <div class="credits"> <p class="dwt_author">Deca, J.; Lapenta, G.; Divin, A. V.; Lembege, B.; Markidis, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">289</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1994E%26PSL.125..211B"> <span id="translatedtitle">Evidence for seafloor <span class="hlt">spreading</span> in the Laxmi Basin, northeastern Arabian Sea</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Main <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data from the Laxmi Basin for the first time reveal the presence of fairly correlatable NNW-trending <span class="hlt">magnetic</span> lineations. These <span class="hlt">magnetic</span> lineations are symmetric about a central negative <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and the axis of symmetry coincides with a characteristic short-wavelength free-air gravity low. The <span class="hlt">anomalies</span> are interpreted as representing a two-limbed seafloor <span class="hlt">spreading</span> sequence which can be equated to the A28-A33 interval of the geomagnetic polarity reversal timescale. These results suggest that the Laxmi Basin is underlain by an oceanic crust. Evidence of seafloor <span class="hlt">spreading</span> in this basin possibly implies a pre-A27 <span class="hlt">spreading</span> episode in the evolutionary history of the Arabian Sea.</p> <div class="credits"> <p class="dwt_author">Bhattacharya, G. C.; Chaubey, A. K.; Murty, G. P. S.; Srinivas, K.; Sarma, K. V. L. N. S.; Subrahmanyam, V.; Krishna, K. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-07-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">290</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2008AGUFMGP43B0814J"> <span id="translatedtitle">Three-Dimensional Mapping of <span class="hlt">Magnetic</span> Strata From Aeromagnetic <span class="hlt">Anomalies</span>: The Deformed Neroly Formation South of Mt. Diablo, Northern California</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We apply direct inversion of aeromagnetic <span class="hlt">anomalies</span> to analyze the subsurface 3D shape of the highly <span class="hlt">magnetic</span> Miocene Neroly Formation, which consists largely of medium to coarse-grained andesitic sandstones containing abundant magnetite. The Neroly Formation is widespread in the eastern San Francisco Bay region, and locally is tightly folded and disrupted by faulting in the compressional regime related to the left-stepping (restraining) connection between the strike-slip Greenville and Concord Faults. The inversion technique is based on the conversion of the <span class="hlt">anomalies</span> produced by a <span class="hlt">magnetic</span> layer to their equivalent <span class="hlt">magnetic</span> potential (psuedogravity) <span class="hlt">anomalies</span>, manipulation of these <span class="hlt">anomalies</span> to produce <span class="hlt">anomalies</span> that would result from a half-space with a variable-depth top having the shape of the top surface of the layer, and then inverting these pseudogravity <span class="hlt">anomalies</span> for the shape of that top surface. Assumptions include a constant layer thickness, uniform <span class="hlt">magnetization</span> which implies a constant pseudodensity contrast, and a surface that is single-valued (no recumbent folds or strata repeated with depth). Constraints on 3D position are applied where the layer crops out or is at a depth known from well or other information. Application of this inversion technique to aeromagnetic <span class="hlt">anomalies</span> over the Neroly Formation yields a complex top surface characterized by elongate overlapping troughs and structural highs, including the well-known Tassajara anticline and adjacent Sycamore Valley syncline. Troughs are true synclinal lows whereas the structural highs may be fold crests, steep truncated strata, and/or fault duplicated strata. The strongest deformation is confined to within ~7 km of the near-vertical overturned Neroly beds that crop out along the NE margin of the valley, and is characterized by four laterally overlapping, margin parallel structural highs and intervening troughs, each between 10 and 20 km in length. A fifth possible structural high lies farther SW. Separation between the highs increases southwestward across strike away from the valley margin. The gross structure implied by the inferred shape of the Neroly layer is that of a 7 km wide, NW oriented doubly- plunging synform with internal, high-amplitude 'wrinkles'. The technique shows promise for application to deformed <span class="hlt">magnetic</span> layers in other regions. Elsewhere in California these include the Purisima Formation of the Hollister Valley and Santa Cruz Mountains, the Etchegoin Formation along the San Andreas Fault near Parkfield, and the Coastal Belt of the Franciscan Complex.</p> <div class="credits"> <p class="dwt_author">Jachens, R. C.; Simpson, R. W.; Graymer, R. W.; Wentworth, C. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">291</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/m273287712673g18.pdf"> <span id="translatedtitle">Mantle Bouguer <span class="hlt">Anomaly</span> Along an Ultra Slow-<span class="hlt">Spreading</span> Ridge: Implications for Accretionary Processes and Comparison with Results from Central Mid-Atlantic Ridge</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A three-dimensional analysis of gravity andbathymetry data has been achieved along the Southwest Indian Ridge (SWIR)between the Rodriguez Triple Junction (RTJ) and the Atlantis II transform,in order to define the morphological and geophysical expression ofsecond-order segmentation along an ultra slow-<span class="hlt">spreading</span> ridge(<span class="hlt">spreading</span> rate of 8 mm\\/yr), and to compare it with awell-studied section along a slow-<span class="hlt">spreading</span> ridge (spreadingrate of 12.5 mm\\/yr):</p> <div class="credits"> <p class="dwt_author">Céline Rommevaux-Jestin; Christine Deplus; Philippe Patriat</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">292</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1982uvpm.rept.....A"> <span id="translatedtitle">The use of VLF phase measurements to associate increased particle precipitation in the region of the Brazilian <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> with <span class="hlt">magnetic</span> storms</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Phase recordings at Atibaia, Brazil, (23 deg S, 46 deg W) of 13.6 KHz VLF signal transmitted from Golfo Nuevo, Argentina (43 deg S, 65 deg W), a trajectory confined almost completely within the South Atlantic <span class="hlt">anomaly</span> region, show significant perturbations, indicative of the lowering of the VLF reflection level, following the onset of <span class="hlt">magnetic</span> disturbances. Simultaneous measurements of the E layer parameters, over Cachoeira Paulista (22 deg S, 45 deg W) also show enhancements, with some delay with respect to the <span class="hlt">magnetic</span> disturbance onset. These results show <span class="hlt">magnetic</span> storm associated ionization enhancements taking place in a height region from approximately 110 km down to 70 km, which is interpreted as having been produced by precipitation of high energy charged particles in the South Atlantic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. The results also suggest some degree of day to day variability in the abundance of metallic species, and/or in the dynamics of the E region over this region.</p> <div class="credits"> <p class="dwt_author">Abdu, M. A.; Batista, I. S.; Piazza, L. R.; Massambani, O.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">293</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012PEPI..204...22B"> <span id="translatedtitle">A new automatic method for estimation of <span class="hlt">magnetization</span> and density contrast by using three-dimensional (3D) <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper, a new method estimating the ratio of <span class="hlt">magnetic</span> intensity to density contrast of a body that creates <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span> is presented. Although <span class="hlt">magnetic</span> intensity and density of an anomalous body can be measured in the laboratory from the surface samples, the proposed new method is developed to determine the <span class="hlt">magnetic</span> intensity and density contrast from the <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span> when the surface samples are not available. In this method, density contrast diagrams of a synthetic model are produced and these diagrams are prepared as graphics where the <span class="hlt">magnetic</span> intensity (J) is given in the vertical axis and Psg (pseudogravity)/Grv (gravity) values in horizontal axis. The density contrast diagrams can be prepared as three sub-diagrams to show the low, middle and high ranges allowing obtain density contrast of body. The proposed method is successfully tested on the synthetic models with and without error. In order to verify the results of the method, an alternative method known as root-mean-square (RMS) is also applied onto the same models to determine the density contrast. In this manner, maximum correlation between the observed gravity and calculated gravity <span class="hlt">anomalies</span> is searched and confirmation of the results is supported with the RMS method. In order to check the reliability of the new method on the field data, the proposed method is applied to the Tetbury (England) and Hanobasi (Central Turkey) <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span>. Field models are correlated with available geological, seismic and borehole data. The results are found consistent and reliable for estimating the <span class="hlt">magnetic</span> intensity and density contrast of the causative bodies.</p> <div class="credits"> <p class="dwt_author">Bektas, Ozcan; Ates, Abdullah; Aydemir, Attila</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">294</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/pp35q54457571721.pdf"> <span id="translatedtitle">Frequency of septum pellucidum <span class="hlt">anomalies</span> in non-psychotic population: a <span class="hlt">magnetic</span> resonance imaging study</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This prospective MRI investigation was performed to investigate septum pellucidum (SP) <span class="hlt">anomalies</span> in 505 (242 male, 263 female) non-psychotic persons. The mean age of the population was 39.179±0.904 (40.461±1.395 male, 38±1.166 female). There was no significant difference between the means of age in the male and female groups (t-test, DF=479, p>0.05). The SP <span class="hlt">anomalies</span> were classified as cavitation <span class="hlt">anomalies</span> (Type</p> <div class="credits"> <p class="dwt_author">M. M. Aldur; F. Gürcan; R. Basar; M. D. Aksit</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">295</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006SSSci...8.1258H"> <span id="translatedtitle">Spin glass <span class="hlt">anomalies</span> in HP-NdPtSn—structural, <span class="hlt">magnetic</span> and specific heat studies</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The hexagonal high-pressure (HP) modification of NdPtSn was prepared under multianvil high-pressure (10.5 GPa) high-temperature (1425 K) conditions from the orthorhombic normal-pressure (NP) modification. NP- and HP-NdPtSn were studied by X-ray powder and single crystal diffraction: TiNiSi type, Pnma, a=737.2(1), b=460.0(1), c=799.6(2) pm, wR2=0.0662, 441 F values, 20 variable parameters for NP-NdPtSn, and ZrNiAl type, P62¯m, a=753.55(5), c=410.55(4) pm, wR2=0.0709, 248 F values, 14 variable parameters for HP-NdPtSn. Temperature dependent susceptibility measurements reveal paramagnetism for HP-NdPtSn above 20 K with an experimental <span class="hlt">magnetic</span> moment of 3.73(2) ?/Nd mol and a paramagnetic Curie temperature ? of -5(1) K. The low-temperature data indicate spin glass behavior with a freezing temperature around 4.5 K. The spin glass <span class="hlt">anomalies</span> are also evident from specific heat measurements.</p> <div class="credits"> <p class="dwt_author">Heymann, Gunter; Rayaprol, Sudhindra; Riecken, Jan F.; Hoffmann, Rolf-Dieter; Rodewald, Ute Ch.; Huppertz, Hubert; Pöttgen, Rainer</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">296</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19870053273&hterms=Weather+Modification&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DWeather%2BModification"> <span id="translatedtitle">Middle atmospheric electrodynamic modification by particle precipitation at the South Atlantic <span class="hlt">magnetic</span> <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Evidence for a localized middle atmospheric electrodynamic modification at low latitudes (southern Brazilian coast) of the South Atlantic <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (SAMA), in association with enhanced geomagnetic activity, are presented in a unified way combining recent observational efforts and related numerical studies. They involve a distortion effect in the fair weather electric field at balloon altitudes. This effect is attributed to a local intensification of energetic electron precipitation through a related middle atmospheric ionization enhancement and is elucidated by numeric simulation. From the electric field measurements and the numeric simulation, the intensification of precipitation is considered to occur in fairly narrow regions at the observed low L values (around L = 1.13) of the SAMA, with horizontal extensions of the order of a few hundred kilometers. A physical mechanism that could be responsible for this sort of intensification is suggested. Furthermore, a comparison of the phenomenon of middle atmospheric electrodynamic modification at the SAMA with a similar one at auroral latitudes, in response to enhanced solar and geomagnetic activity, is also given.</p> <div class="credits"> <p class="dwt_author">Gonzalez, W. D.; Dutra, S. L. G.; Pinto, O., Jr.</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">297</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2003EAEJA.....9362S"> <span id="translatedtitle">Coorelation between VHF scintillation and <span class="hlt">spread</span> F</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The VHF scintillation observed over Bhopal, a station near the northern crest of the equatorial <span class="hlt">anomaly</span> region, using the 244 MHz radio signal from FLEETSAT (730). The data use to study the occurrence characteristics of scintillation are recorded from March to April 2001 and then September to October 2001. The occurrences of scintillation are compared with the occurrence of <span class="hlt">spread</span>-F over Delhi as observed by the modern digital ionosonde. The scintillation events are closely associated with the range type <span class="hlt">spread</span>-F. In this paper the parameters of geomagnetic activity like Kp and Ap are used to study the association of the amplitude scintillation and <span class="hlt">spread</span>-F. It is observed that an increase in <span class="hlt">magnetic</span> activity suppressed the occurrence of scintillation and <span class="hlt">spread</span>-F.</p> <div class="credits"> <p class="dwt_author">Smita, S.; Rashmi, R.; Gwal, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">298</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/22723478"> <span id="translatedtitle">Conditioned response to a <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in the Pekin duck (Anas platyrhynchos domestica) involves the trigeminal nerve.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">There have been recent calls to develop protocols that collect unambiguous measures of behaviour using automatic techniques in conditioning experiments on <span class="hlt">magnetic</span> orientation. Here, we describe an automated technique for recording the behaviour of Pekin ducks in a conditioning test that allows them to express unrestricted searching behaviour. Pekin ducks were trained to find hidden food in one corner of a square arena below which was placed a <span class="hlt">magnetic</span> coil that produced a local <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. The trigeminal nerve was anaesthetised by injection of lignocaine hydrochloride 2-3 mm caudal to the medial canthus of each eye, medial to the globe, prior to the presentation of unrewarded tests. Lignocaine-treated ducks showed no initial preference for the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> whereas saline-treated control ducks showed a significant preference at the same age. A second experiment was undertaken in which the trigeminal nerve was surgically severed and 2-3 mm removed, and this surgery abolished the previously observed preference for the corner with the <span class="hlt">magnetic</span> coil in a small number of ducks. These data show that Pekin ducks are able to detect and use <span class="hlt">magnetic</span> stimuli to guide unrestricted search behaviour and are consistent with a hypothesis of magnetoreception involving a putative cluster of magnetite in the upper beak. PMID:22723478</p> <div class="credits"> <p class="dwt_author">Freire, Rafael; Dunston, Emma; Fowler, Emmalee M; McKenzie, Gary L; Quinn, Christopher T; Michelsen, Jacob</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-07-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">299</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007AGUFM.T13A1130P"> <span id="translatedtitle">Calibration of Pre-M25 Marine <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span>: <span class="hlt">Magnetic</span> Polarity Composite of ýLate Callovian Through Kimmeridgian</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Ammonite-zoned successions have yielded a composite <span class="hlt">magnetic</span> polarity pattern ýspanning latest Callovian (lamberti ammonite Zone) through Late Kimmeridgian ýý(acanthicum Zone) that confirms marine <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> M37 through to M24 ýinterpreted by deep-tow and other <span class="hlt">magnetic</span> surveys in the western Pacific. This pattern ýwas constructed after thermal demagnetization of over 1000 samples from over 30 ýsections in Poland, British Isles, France and Spain. Polish sections include thick ýammonite-zoned limestone formations of the Krakow-Czestochowa-Wielun Upland and ýHoly-Cross Mountains. British limestone and clay formations were investigated in ýEngland (Dorset and Yorkshire) and in Scotland (the Isle of Skye). The sections include ýcandidates for the global stratotypes for the Callovian-Oxfordian and Oxfordian-ýKimmeridgian stage boundaries. All British and most of the Polish-French-Spanish ýsections are calibrated to ammonite biostratigraphy at the subzone level (Boreal-ýSubboreal realm and Sub-Mediterranean realm, respectively) and to regional sequence ýstratigraphy. The independent Boreal-Subboreal and Sub-Mediterranean composites of ýmagnetic polarity are consistent, and the main features of the modeled pre-M25 marine ýmagnetics can be calibrated. ý The Callovian-Oxfordian boundary (base of Quenstedtoceras mariae Zone) occurs in a ýnarrow normal-polarity subzone correlated to polarity subchron M36a of the western ýPacific <span class="hlt">magnetic</span> polarity pattern. The beginning of the Middle and the Late Oxfordian ýsubstages as defined in the Sub-Mediterranean province in Poland correspond ýapproximately to M33 and M29 of the Pacific M-sequence. The placement of the ýOxfordian- Kimmeridgian boundary in the Sub-Boreal ammonite zonation (base of ýPictonia baylei Zone) is at the beginning of the M27r polarity zone. This is significantly ýolder than the traditional placement of the Oxfordian-Kimmeridgian boundary in the ýSub-Mediterranean zonation (base of Sutneria platynota Zone) near the base of the M25r ýpolarity zone.ý This project is a collaboration with A. Wierzbowski, M. Lewandowski, E. Glowniak, J. ýGutowski, P. Ziolkowski, M. Sidorczuk, and Z. Zlonkiewicz (Poland); A. Coe and J. ýWright, (England); and N. Nowaczyk (Germany)ý</p> <div class="credits"> <p class="dwt_author">Przybylski, P. A.; Ogg, J. G.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">300</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/17664646"> <span id="translatedtitle"><span class="hlt">Magnetic</span> induction tomography: evaluation of the point <span class="hlt">spread</span> function and analysis of resolution and image distortion.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary"><span class="hlt">Magnetic</span> induction tomography (MIT) is a low-resolution imaging modality used for reconstructing the changes of the passive electrical properties in a target object. For an imaging system, it is very important to give forecasts about the image quality. Both the maximum resolution and the correctness of the location of the inhomogeneities are of major interest. Furthermore, the smallest object which can be detected for a certain noise level is a criterion for the diagnostic value of an image. The properties of an MIT image are dependent on the position inside the object, the conductivity distribution and of course on the location and the number of excitation coils and receiving coils. Quantitative statements cannot be made in general but it is feasible to predict the image quality for a selected problem. For electrical impedance tomography (EIT), the theoretical limits of image quality have been studied carefully and a comprehensive analysis for MIT is necessary. Thus, a simplified analysis on resolution, dimensions and location of an inhomogeneity was carried out by means of an evaluation of the point <span class="hlt">spread</span> function (PSF). In analogy to EIT the PSF depends strongly on the location, showing the broadest distribution in the centre of the object. Increasing the amount of regularization according to increasing measurement noise, the PSF broadens and its centre is shifted towards the borders of the object. The resolution is indirectly proportional to the width of the PSF and increases when moving from the centre towards the border of the object and decreases with increasing noise. PMID:17664646</p> <div class="credits"> <p class="dwt_author">Merwa, Robert; Scharfetter, Hermann</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-07-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_14");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">301</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009AGUFMGP43A0836R"> <span id="translatedtitle"><span class="hlt">Magnetic</span> Properties from the East Rift Zone of Kilauea: Implications for the Sources of Aeromagnetic <span class="hlt">Anomalies</span> over Hawaiian Volcanoes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Aeromagnetic studies of the Island of Hawai‘i provide insights into geologic structure. High-amplitude short-wavelength <span class="hlt">anomalies</span> occur along the southwest and east rift zones (ERZ) of Kilauea, the youngest volcano on the island. These <span class="hlt">anomalies</span> have been attributed to contrast between highly <span class="hlt">magnetic</span> intrusions at depth and less <span class="hlt">magnetic</span> altered rocks. <span class="hlt">Anomalies</span> along rift zones of the older volcanoes on the island have lower amplitude or are lacking. To better understand the origin of the high-amplitude <span class="hlt">anomalies</span>, <span class="hlt">magnetic</span> properties were obtained for samples from existing 1.7 - 2.0 km deep bore holes located on the ERZ 30 - 40 km east of the summit of Kilauea but not over associated aeromagnetic maxima. The bore holes penetrate subaerial flows, submarine flows, and intrusions. Average values of total <span class="hlt">magnetization</span> (MT) based on measurements of <span class="hlt">magnetic</span> susceptibility (?) and NRM range from ~5.5 A/m for terrestrial flows to ~10 A/m for pillow basalts. MT of intrusions varys with depth. In shallow intrusions (< ~850 m depth), MT averages ~12 A/m, whereas in deep intrusions MT averages ~9 A/m. In contrast, to flows and shallow intrusions, deep intrusions have unstable NRMs that commonly diminish >80% during AF demagnetization at a peak field of 10 mT. The NRMs of deep intrusions were probably affected by drilling, and consequently their laboratory MT values may be much larger than in situ values. Therefore, the deep intrusions are more likely to have relatively low <span class="hlt">magnetizations</span> rather than the high <span class="hlt">magnetizations</span> that were used in previous aeromagnetic models.¶ The contrast in NRM stability for shallow and deep intrusions reflects differences in <span class="hlt">magnetic</span> grain size. The average ARM/? for shallow intrusions is ~4 times that of deep intrusions. Also, deep intrusions have high Curie temperatures (TC>550 °C) whereas shallow intrusions commonly have low TC, averaging ~165 °C. The fine <span class="hlt">magnetic</span> grain size and low TC of shallow intrusions are interpreted as the result of rapid crystallization after degassing. Limited oxygen in the subsurface environment would inhibit formation of ilmenite and thereby preserve high Ti-magnetite.¶ After heating in air to ~300 °C and above, TC and room-temperature saturation <span class="hlt">magnetization</span> (MS) of shallow intrusions increase dramatically. On average, MS at ~25 °C of shallow intrusions increases by a factor of 2.4 after heating to 600 °C. Susceptibility increases similarly after heating in air but does not increase after heating in argon. In the presence of oxygen, Ti apparently separates even at moderate temperature, raising the TC and thereby MS and ?. If NRM increases in a similar manner (as is reasonable if the fine <span class="hlt">magnetic</span> grain size is preserved), these rocks could attain MT in excess of 20 - 25 A/m. We speculate that this process occurs naturally in proximity to vents where repeated intrusions reheated (or maintained) these rocks to moderate temperatures. If such rocks are the source of <span class="hlt">anomalies</span> along the Kilauea rift zones then destruction of the fine-grained titanomagnetite over time could explain the lack of prominent <span class="hlt">anomalies</span> along older rift zones.</p> <div class="credits"> <p class="dwt_author">Rosenbaum, J. G.; Reynolds, R. L.; Trusdell, F.; Kauahikaua, J. P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">302</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=20120011638&hterms=Tectonic+Plates&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2522Tectonic%2BPlates%2522"> <span id="translatedtitle">Interpretation of the Total <span class="hlt">Magnetic</span> Field <span class="hlt">Anomalies</span> Measured by the CHAMP Satellite Over a Part of Europe and the Pannonian Basin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">In this study we interpret the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> at satellite altitude over a part of Europe and the Pannonian Basin. These <span class="hlt">anomalies</span> are derived from the total <span class="hlt">magnetic</span> measurements from the CHAMP satellite. The <span class="hlt">anomalies</span> reduced to an elevation of 324 km. An inversion method is used to interpret the total <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> over the Pannonian Basin. A three dimensional triangular model is used in the inversion. Two parameter distributions: Laplacian and Gaussian are investigated. The regularized inversion is numerically calculated with the Simplex and Simulated Annealing methods and the anomalous source is located in the upper crust. A probable source of the <span class="hlt">magnetization</span> is due to the exsolution of the hematite-ilmenite minerals.</p> <div class="credits"> <p class="dwt_author">Kis, K. I.; Taylor, Patrick T.; Wittmann, G.; Toronyi, B.; Puszta, S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">303</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.apgeochem.2009.04.007"> <span id="translatedtitle">Airborne gamma-ray and <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> signatures of serpentinite in relation to soil geochemistry, northern California</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">Serpentinized ultramafic rocks and associated soils in northern California are characterized by high concentrations of Cr and Ni, low levels of radioelements (K, Th, and U) and high amounts of ferrimagnetic minerals (primarily magnetite). Geophysical attributes over ultramafic rocks, which include airborne gamma-ray and <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> data, are quantified and provide indirect measurements on the relative abundance of radioelements and <span class="hlt">magnetic</span> minerals, respectively. Attributes are defined through a statistical modeling approach and the results are portrayed as probabilities in chart and map form. Two predictive models are presented, including one derived from the aeromagnetic <span class="hlt">anomaly</span> data and one from a combination of the airborne K, Th and U gamma-ray data. Both models distinguish preferential values within the aerogeophysical data that coincide with mapped and potentially unmapped ultramafic rocks. The <span class="hlt">magnetic</span> predictive model shows positive probabilities associated with <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> highs and, to a lesser degree, <span class="hlt">anomaly</span> lows, which accurately locate many known ultramafic outcrops, but more interestingly, locate potentially unmapped ultramafic rocks, possible extensions of ultramafic bodies that dip into the shallow subsurface, as well as prospective buried ultramafic rocks. The airborne radiometric model shows positive probabilities in association with anomalously low gamma radiation measurements over ultramafic rock, which is similar to that produced by gabbro, metavolcanic rock, and water bodies. All of these features share the characteristic of being depleted in K, Th and U. Gabbro is the only rock type in the study area that shares similar <span class="hlt">magnetic</span> properties with the ultramafic rock. The aerogeophysical model results are compared to the distribution of ultramafic outcrops and to Cr, Ni, K, Th and U concentrations and <span class="hlt">magnetic</span> susceptibility measurements from soil samples. Analysis of the soil data indicates high positive correlation between <span class="hlt">magnetic</span> susceptibilities and concentration of Cr and Ni. Although the study focused on characterizing the geophysical properties of ultramafic rocks and associated soils, it has also yielded information on other rock types in addition to ultramafic rocks, which can also locally host naturally-occurring asbestos; specifically, gabbro and metavolcanic rocks.</p> <div class="credits"> <p class="dwt_author">McCafferty, A. E.; Van Gosen, B. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">304</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/836904"> <span id="translatedtitle"><span class="hlt">ANOMALIES</span> IN THE APPLIED <span class="hlt">MAGNETIC</span> FIELDS ON DIII-D AND THEIR IMPLICATIONS FOR THE UNDERSTANDING OF STABILITY EXPERIMENTS</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Small non-axisymmetric <span class="hlt">magnetic</span> fields are known to cause serious loss of stability in tokamaks leading to loss of confinement and abrupt termination of plasma current (disruptions). The best known examples are the locked mode and the resistive wall mode. Understanding of the underlying field <span class="hlt">anomalies</span> (departures in the hardware-related fields from ideal toroidal and poloidal fields on a single axis) and the interaction of the plasma with them is crucial to tokamak development. Results of both locked mode experiments and resistive wall mode experiments done in DIII-D tokamak plasmas have been interpreted to indicate the presence of a significant anomalous field. New measurements of the <span class="hlt">magnetic</span> field <span class="hlt">anomalies</span> of the hardware systems have been made on DIII-D. The measured field <span class="hlt">anomalies</span> due to the plasma shaping coils in DIII-D are smaller than previously reported. Additional evaluations of systematic errors have been made. New measurements of the anomalous fields of the ohmic heating and toroidal coils have been added. Such detailed in situ measurements of the fields of a tokamak are unique. The anomalous fields from all of the coils are one third of the values indicated from the stability experiments. These results indicate limitations in the understanding of the interaction of the plasma with the external field. They indicate that it may not be possible to deduce the anomalous fields in a tokamak from plasma experiments and that we may not have the basis needed to project the error field requirements of future tokamaks.</p> <div class="credits"> <p class="dwt_author">LUXON,J.L; SCHAFFER,M.J; JACKSON,G.L; LEUER,J.A; NAGY,A; SCOVILLE,J.T; STRAIT,E.J</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-02-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">305</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41998547"> <span id="translatedtitle">A closer look at remanence-dominated aeromagnetic <span class="hlt">anomalies</span>: Rock <span class="hlt">magnetic</span> properties and <span class="hlt">magnetic</span> mineralogy of the Russell Belt microcline-sillimanite gneiss, northwest Adirondack Mountains, New York</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A large, distinct negative aeromagnetic <span class="hlt">anomaly</span> of over 2000 nT associated with microcline-sillimanite-quartz gneisses in the Russell area, northwest Adirondack Mountains, was previously shown to be remanence-dominated, although the carriers of remanence were not well documented. Russell Belt gneisses have a strong natural remanent <span class="hlt">magnetization</span> with steep remanence directions, D=263°, I=-58°, an average intensity of 3.6 A\\/m, and typical susceptibilities</p> <div class="credits"> <p class="dwt_author">Suzanne A. McEnroe; Laurie L. Brown</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">306</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54361564"> <span id="translatedtitle">A different pattern of ridge segmentation and mantle Bouguer gravity <span class="hlt">anomalies</span> along the ultra-slow <span class="hlt">spreading</span> Southwest Indian Ridge (15°30'E to 25°E)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The results of a recent bathymetric and geophysical investigation of a ~650 km-long portion of the very slowly opening (16 mm\\/yr full rate) Southwest Indian Ridge (SWIR) between 15°30'E and 25°E are presented. Bathymetry and mantle Bouguer gravity <span class="hlt">anomalies</span> (MBA), caused by variations in crustal thickness and\\/or crustal and upper mantle densities, show different characteristics from those observed at faster</p> <div class="credits"> <p class="dwt_author">Nancy R. Grindlay; John A. Madsen; Celine Rommevaux-Jestin; John Sclater</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">307</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/5549415"> <span id="translatedtitle">A different pattern of ridge segmentation and mantle Bouguer gravity <span class="hlt">anomalies</span> along the ultra-slow <span class="hlt">spreading</span> Southwest Indian Ridge (15°30?E to 25°E)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The results of a recent bathymetric and geophysical investigation of a ?650 km-long portion of the very slowly opening (16 mm\\/yr full rate) Southwest Indian Ridge (SWIR) between 15°30?E and 25°E are presented. Bathymetry and mantle Bouguer gravity <span class="hlt">anomalies</span> (MBA), caused by variations in crustal thickness and\\/or crustal and upper mantle densities, show different characteristics from those observed at faster</p> <div class="credits"> <p class="dwt_author">Nancy R. Grindlay; John A. Madsen; Celine Rommevaux-Jestin; John Sclater</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">308</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014Icar..237..262A"> <span id="translatedtitle">Analysis of isolated <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and <span class="hlt">magnetic</span> signatures of impact craters: Evidence for a core dynamo in the early history of the Moon</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We investigate the possibility that a strong core dynamo of the Moon has <span class="hlt">magnetized</span> the lunar crust. The <span class="hlt">magnetic</span> data from two missions, Lunar Prospector and Kaguya, are used and the <span class="hlt">magnetic</span> fields of two different features are examined: The isolated small <span class="hlt">magnetic</span> source bodies with almost no topographic signatures, and the impact craters with diameters larger than 100 km. Five data sets are examined separately for each of the isolated <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>: the r, ?, and ? components of the Lunar Prospector data, the r component of a 150-degree spherical harmonic model of the lunar <span class="hlt">magnetic</span> field, and the r component of the Kaguya data. The r component of the Lunar Prospector data is also used to derive the <span class="hlt">magnetic</span> field over the impact craters. We conclude that most of the ancient lunar far side crust is heterogeneously <span class="hlt">magnetized</span> with coherency wavelength about a few hundred km. The paleomagnetic north poles determined from modeling the <span class="hlt">magnetic</span> field of both features show some clustering whereas the source bodies are widely distributed, suggesting that the <span class="hlt">magnetizing</span> field may have been a core dynamo field. Paleointensity data suggest that the core field intensity was at least 1 mT at the core mantle boundary. There is also evidence for core field reversals, because further clustering occurs when the south poles of some features are considered.</p> <div class="credits"> <p class="dwt_author">Arkani-Hamed, Jafar; Boutin, Daniel</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">309</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5112377"> <span id="translatedtitle"><span class="hlt">Magnetic</span>-field-dependent zero-bias <span class="hlt">anomaly</span> in Al-oxide-Ga (granular) thin-film tunnel junctions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">High-T/sub c/ gallium films were prepared by evaporating gallium in partial pressure of oxygen and electron tunneling characteristics of tunnel junctions of the form Al-oxide-Ga were studied with gallium film being in the superconducting and in the normal states. In the superconducting state a sharp, single gap was observed, and from these characteristics it was ascertained that the mechanism of current flow was indeed through electron tunneling. In the normal state a <span class="hlt">magnetic</span>-field-dependent zero-bias <span class="hlt">anomaly</span> corresponding to a resistance maximum at zero bias was observed. The conductance varied as V/sup 1/2/ for all the <span class="hlt">magnetic</span> field values. The bias dependence is in agreement with recent theories on metal-insulator transition in amorphous materials; however, the <span class="hlt">magnetic</span> field dependence is a novel feature.</p> <div class="credits"> <p class="dwt_author">Sood, B.R.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-05-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">310</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6135982"> <span id="translatedtitle">Preliminary interpretation of mid-crustal reflections from the vicinity of the New York-Alabama <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span>, eastern Tennessee</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Seismic data acquired across part of the New York-Alabama <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> reveal 30 km of highly reflective crust from 4.5 to 16 km depth (1.6 to 5.0 sec) beneath the Alleghenian allochthon. At the southeast end of the SE-NW oriented seismic line, the reflections range from essentially horizontal to gently west-dipping at about 30 degrees. The dominant west-dipping reflections are interspersed with short east-dipping events on the southeastern part of the line. Near the center of the line, the west-dipping reflections reverse dip to form a broad, open synformal geometry. The NW end of the line is characterized by a zone of low reflectivity. The reflection geometries can be viewed as resulting from extensional block faulting, where the region has been down-faulted to the west. In some places,the west-dipping reflections appear to connect to the short east-dipping reflections to form open, asymmetric antiforms. Coupled with the presence of the syncline on the northwestern part of the line,the reflection geometry can be interpreted as originating in a compressional setting. Alternatively, the west-dipping reflections might represent unusually well preserved compositional layering, sills, or a regional scale metamorphic fabric. Additional models can be proposed to explain the data, but all must account for the excellent preservation of the seismic features. These data are used with potential field data in an effort to determine whether the cause of the New York-Alabama <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> is similar to that associated with the Central North American Rift System and/or the Grenville Front <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span>.</p> <div class="credits"> <p class="dwt_author">Hopkins, D.L.; Costain, J.K. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences)</p> <p class="dwt_publisher"></p> <p class="publishDate">1992-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">311</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009JGRB..114.3102K"> <span id="translatedtitle">Geoid and gravity <span class="hlt">anomaly</span> data of conjugate regions of Bay of Bengal and Enderby Basin: New constraints on breakup and early <span class="hlt">spreading</span> history between India and Antarctica</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Timing of breakup of the Indian continent from eastern Gondwanaland and evolution of the lithosphere in the Bay of Bengal still remain as ambiguous issues. Geoid and free-air gravity data of Bay of Bengal and Enderby Basin are integrated with shipborne geophysical data to investigate the early evolution of the eastern Indian Ocean. Geoid and gravity data of the Bay of Bengal reveal five N36°W fracture zones (FZs) and five isolated NE-SW structural rises between the Eastern Continental Margin of India (ECMI) and the 85°E Ridge/86°E FZ. The FZs meet the 86°E FZ at an angle of ˜39°. The rises are associated with low-gravity and geoid <span class="hlt">anomalies</span> and are oriented nearly orthogonal to the FZs trend. The geoid and gravity data of the western Enderby Basin reveal a major Kerguelen FZ and five N4°E FZs. The FZs discretely converge to the Kerguelen FZ at an angle of ˜37°. We interpret the FZs identified in Bay of Bengal and western Enderby Basin as conjugate FZs that trace the early Cretaceous rifting of south ECMI from Enderby Land. Structural rises between the FZs of Bay of Bengal may either represent fossil ridge segments, possibly have extinct during the early evolution of the Bay of Bengal lithosphere or may have formed later by the volcanic activity accreted the 85°E Ridge. Two different gravity signatures (short-wavelength high-amplitude negative gravity <span class="hlt">anomaly</span> and relatively broader low-amplitude negative gravity <span class="hlt">anomaly</span>) are observed on south and north segments of the ECMI, respectively. The location of continent-ocean boundary (COB) is at relatively far distance (100-200 km) from the coastline on north ECMI than that (50-100 km) on the south segment. On the basis of geoid, gravity, and seismic character and orientation of conjugate FZs in Bay of Bengal and western Enderby Basin, we believe that transform motion occurred between south ECMI and Enderby Land at the time of breakup, which might have facilitated the rifting process in the north between combined north ECMI-Elan Bank and MacRobertson Land and in the south between southwest Sri Lanka and Gunnerus Ridge region of East Antarctica. Approximately during the period between the <span class="hlt">anomalies</span> M1 and M0 and soon after detachment of the Elan Bank from north ECMI, the rifting process possibly had reorganized in order to establish the process along the entire eastern margins of India and Sri Lanka.</p> <div class="credits"> <p class="dwt_author">Krishna, K. S.; Michael, Laju; Bhattacharyya, R.; Majumdar, T. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">312</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012GeoJI.191.1049K"> <span id="translatedtitle">Modelling of the total electronic content and <span class="hlt">magnetic</span> field <span class="hlt">anomalies</span> generated by the 2011 Tohoku-Oki tsunami and associated acoustic-gravity waves</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this work, numerical simulations of the atmospheric and ionospheric <span class="hlt">anomalies</span> are performed for the Tohoku-Oki tsunami (2011 March 11). The Tsunami-Atmosphere-Ionosphere (TAI) coupling mechanism via acoustic gravity waves (AGWs) is explored theoretically using the TAI-coupled model. For the modelled tsunami wave as an input, the coupled model simulates the wind, density and temperature disturbances or <span class="hlt">anomalies</span> in the atmosphere and electron density/<span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the F region of the ionosphere. Also presented are the GPS-total electron content (TEC) and ground-based magnetometer measurements during the first hour of tsunami and good agreements are found between modelled and observed <span class="hlt">anomalies</span>. At first, within 6 min from the tsunami origin, the simulated wind <span class="hlt">anomaly</span> at 250 km altitude and TEC <span class="hlt">anomaly</span> appear as the dipole-shaped disturbances around the epicentre, then as the concentric circular wave fronts radially moving away from the epicentre with the horizontal velocity ˜800 m s-1 after 12 min followed by the slow moving (horizontal velocity ˜250 m s-1) wave disturbance after 30 min. The detailed vertical-horizontal propagation characteristics suggest that the <span class="hlt">anomalies</span> appear before and after 30 min are associated with the acoustic and gravity waves, respectively. Similar propagation characteristics are found from the GPS-TEC and <span class="hlt">magnetic</span> measurements presented here and also reported from recent studies. The modelled <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in the F region ionosphere is found to have similar temporal variations with respect to the epicentre distance as that of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> registered from the ground-based magnetometers. The high-frequency component ˜10 min of the simulated wind, TEC and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the F region develops within 6-7 min after the initiation of the tsunami, suggesting the importance of monitoring the high-frequency atmospheric/ionospheric <span class="hlt">anomalies</span> for the early warning. These <span class="hlt">anomalies</span> are found to maximize across the epicentre in the direction opposite to the tsunami propagation suggesting that the large atmospheric/ionospheric disturbances are excited in the region where tsunami does not travel.</p> <div class="credits"> <p class="dwt_author">Kherani, E. A.; Lognonné, P.; Hébert, H.; Rolland, L.; Astafyeva, E.; Occhipinti, G.; Coïsson, P.; Walwer, D.; de Paula, E. R.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">313</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://svs.gsfc.nasa.gov/vis/a000000/a002600/a002695/index.html"> <span id="translatedtitle">SST <span class="hlt">Anomalies</span> + Wind <span class="hlt">Anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://nsdl.org/nsdl_dds/services/ddsws1-1/service_explorer.jsp">NSDL National Science Digital Library</a></p> <p class="result-summary">Sea surface temperature (SST) <span class="hlt">anomalies</span> and sea surface wind <span class="hlt">anomalies</span> show the development of the 2002-2003 El Nino based on data from NASAs Aqua and QuikSCAT spacecraft. The wind data has been processed using the Variational Analysis Method (VAM).</p> <div class="credits"> <p class="dwt_author">Shirah, Greg; Allen, Jesse; Adamec, David</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-02-03</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">314</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/39935677"> <span id="translatedtitle">Interpretation of total intensity <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> when anomalous field is arbitrarily large</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Not infrequently, in mining geophysics, the anomalous field of the <span class="hlt">magnetized</span> body is appreciably large and it varies from the direction of the earth's normal field within the vicinity of the <span class="hlt">magnetized</span> body. Total <span class="hlt">magnetic</span> intensity data collected on the ground over shallow <span class="hlt">magnetized</span> bodies cannot be interpreted quantitatively, since all the available methods of interpretation assume that the resultant</p> <div class="credits"> <p class="dwt_author">M. N. Ramanaiah Chowdary</p> <p class="dwt_publisher"></p> <p class="publishDate">1971-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">315</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JGRB..118.5147H"> <span id="translatedtitle">Deep-sea <span class="hlt">magnetic</span> vector <span class="hlt">anomalies</span> over the Hakurei hydrothermal field and the Bayonnaise knoll caldera, Izu-Ogasawara arc, Japan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We conducted deep-sea <span class="hlt">magnetic</span> measurements using autonomous underwater vehicles in the Bayonnaise knoll caldera, the Izu-Ogasawara island arc, which hosts the large Hakurei hydrothermal field. We improved the conventional correction method applied for removing the effect of vehicle <span class="hlt">magnetization</span>, thus greatly enhancing the precision of the resulting vector <span class="hlt">anomalies</span>. The <span class="hlt">magnetization</span> distribution obtained from the vector <span class="hlt">anomaly</span> data shows a ˜2 km wide belt of high <span class="hlt">magnetization</span>, trending NNW-SSE going through the caldera, and a low-<span class="hlt">magnetization</span> zone ˜300 m by ˜500 m in area, extending over the Hakurei site. Comparison between the results obtained using the vector <span class="hlt">anomaly</span> and the total intensity <span class="hlt">anomaly</span> shows that the <span class="hlt">magnetic</span> field is determined more accurately, especially in areas of sparse data distribution, when the vector <span class="hlt">anomaly</span> rather than the total intensity <span class="hlt">anomaly</span> is used. We suggest a geologically motivated model that basaltic volcanism associated with the back-arc rifting occurred after the formation of the caldera, resulting in the formation of the high-<span class="hlt">magnetization</span> belt underneath the silicic caldera. The Hakurei hydrothermal field lies in the intersection of the basaltic volcanism belt and the caldera wall fault, suggesting a mechanism that hot water generated by the heat of the volcanic activity has been spouting out through the caldera wall fault. The deposit apparently extends beyond the low-<span class="hlt">magnetization</span> zone, climbing up the caldera wall. This may indicate that hot water rising from the deep through the alteration zone is transported laterally when it comes near the seafloor along fissures and fractures in the caldera wall.</p> <div class="credits"> <p class="dwt_author">Honsho, Chie; Ura, Tamaki; Kim, Kangsoo</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-10-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">316</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/2267380"> <span id="translatedtitle">[Trans-sphenoidal <span class="hlt">spread</span> of rhinopharyngeal neoplasms. Correlations between computerized tomography and <span class="hlt">magnetic</span> resonance].</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">In 1957 Teoh observed, in an autopsic series of 31 patients with nasopharyngeal carcinoma, 3 cases of neoplastic <span class="hlt">spread</span> through the marrow spaces of the base of the skull, without macroscopic bone alterations. In order to demonstrate in vivo this kind of neoplastic <span class="hlt">spread</span>, CT and MR examinations of 35 patients with nasopharyngeal carcinoma were reviewed. In 3/26 cases the invasion of the marrow spaces of the clivus was demonstrated. In these cases CT showed only minimal alterations in spongiosa and cortices of the clivus, associated with intracranial soft-tissue tumoral components. MR imaging demonstrated, with great accuracy, the replacement of bone marrow in the clivus by neoplastic tissue of intermediate signal intensity on T1-weighted images. Tumor tissue was characterized by high signal intensity on T2-weighted images. The authors stress the greater utility of MR imaging in evaluating the permeative involvement of the base of the skull. PMID:2267380</p> <div class="credits"> <p class="dwt_author">Pandolfo, I; Longo, M; Girone, G; Gaeta, M; Blandino, A; Salvi, L</p> <p class="dwt_publisher"></p> <p class="publishDate">1990-11-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">317</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1998E%26PSL.160..463S"> <span id="translatedtitle">The Reykjanes Ridge: structure and tectonics of a hot-spot-influenced, slow-<span class="hlt">spreading</span> ridge, from multibeam bathymetry, gravity and <span class="hlt">magnetic</span> investigations</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report a comprehensive morphological, gravity and <span class="hlt">magnetic</span> survey of the oblique- and slow-<span class="hlt">spreading</span> Reykjanes Ridge near the Iceland mantle plume. The survey extends from 57.9°N to 62.1°N and from the <span class="hlt">spreading</span> axis to between 30 km (3 Ma) and 100 km (10 Ma) off-axis; it includes 100 km of one arm of a diachronous `V-shaped' or `chevron' ridge. Observed isochrons are extremely linear and 28° oblique to the <span class="hlt">spreading</span> normal with no significant offsets. Along-axis there are ubiquitous, en-echelon axial volcanic ridges (AVRs), sub-normal to the <span class="hlt">spreading</span> direction, with average spacing of 14 km and overlap of about one third of their lengths. Relict AVRs occur off-axis, but are most obvious where there has been least axial faulting, suggesting that elsewhere they are rapidly eroded tectonically. AVRs maintain similar plan views but have reduced heights nearer Iceland. They are flanked by normal faults sub-parallel to the ridge axis, the innermost of which occur slightly closer to the axis towards Iceland, suggesting a gradual reduction of the effective lithospheric thickness there. Generally, the amplitude of faulting decreases towards Iceland. We interpret this pattern of AVRs and faults as the response of the lithosphere to oblique <span class="hlt">spreading</span>, as suggested by theory and physical modelling. An axial, 10-15 km wide zone of high acoustic backscatter marks the most recent volcanic activity. The zone's width is independent of the presence of a median valley, so axial volcanism is not primarily delimited by median valley walls, but is probably controlled by the lateral distance that the oblique AVRs can propagate into off-axis lithosphere. The mantle Bouguer <span class="hlt">anomaly</span> (MBA) exhibits little mid- to short-wavelength variation above a few milliGals, and along-axis variations are small compared with other parts of the Mid-Atlantic Ridge. Nevertheless, there are small axial deeps and MBA highs spaced some 130 km along-axis that may represent subdued third-order segment boundaries. They lack coherent off-axis traces and cannot be linked to Oligocene fracture zones on the ridge flanks. The surveyed chevron ridge is morphologically discontinuous, comprising several parallel bands of closely spaced, elevated blocks. These reflect the surrounding tectonic fabric but have higher fault scarps. There is no evidence for off-axis volcanism or greater abundance of seamounts on the chevron. Free-air gravity over it is greater than expected from the observed bathymetry, suggesting compensation via regional rather than pointwise isostasy. Most of the observed variation along the ridge can be ascribed to varying distance from the mantle plume, reflecting changes in mantle temperature and consequently in crustal thickness and lithospheric strength. However, a second-order variation is superimposed. In particular, between 59°30'N and 61°30'N there is a minimum of large-scale faulting and crustal magnetisation, maximum density of seamounts, and maximum axial free-air gravity high. To the north the scale of faulting increases slightly, seamounts are less common, and there is a relative axial free-air low. We interpret the 59°30'N to 61°30'N region as where the latest chevron ridge intersects the Reykjanes Ridge axis, and suggest that the morphological changes that culminate there reflect a local temperature high associated with a transient pulse of high plume output at its apex.</p> <div class="credits"> <p class="dwt_author">Searle, R. C.; Keeton, J. A.; Owens, R. B.; White, R. S.; Mecklenburgh, R.; Parsons, B.; Lee, S. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1998-08-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">318</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40951694"> <span id="translatedtitle">Morphology of the <span class="hlt">magnetic</span> field near Mars and the role of the <span class="hlt">magnetic</span> crustal <span class="hlt">anomalies</span>: Dayside region</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have studied the morphology of <span class="hlt">magnetic</span> flux tubes near Mars and have found that the <span class="hlt">magnetic</span> field lines near Mars forms a wing-like flux tube structure downstream of the bow shock. These <span class="hlt">magnetic</span> flux tubes are concentrated close to the plane, which contains the center of Mars, the interplanetary <span class="hlt">magnetic</span> field, and the Mars–Sun line. Regions near Mars on</p> <div class="credits"> <p class="dwt_author">E. Kallio; R. A. Frahm; Y. Futaana; A. Fedorov; P. Janhunen</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">319</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N8420946"> <span id="translatedtitle">Petrologic and Geophysical Study of the Source of Long Wavelength Crustal <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span>.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The <span class="hlt">magnetic</span> mineralogy and <span class="hlt">magnetic</span> signature of banded ion formations, diagenetic (unmetamorphosed) and low grade banded iron formations, high-grade mineralogy, and phase equilibria of magnetite inorogenic magmers are discussed.</p> <div class="credits"> <p class="dwt_author">B. Marsch C. Schlinger</p> <p class="dwt_publisher"></p> <p class="publishDate">1983-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">320</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013EGUGA..1514134K"> <span id="translatedtitle">Deep <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> sources interpreted as Otanmäki type Iron ore reserves</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In Otanmäki ore province of Central Finland vertically integrated <span class="hlt">magnetization</span> is estimated from two aeromagnetic coverages of different altitudes and by varying overall models of regional field. Petrophysically and geochemically determined <span class="hlt">magnetization</span> of the mined deposits and correlation between it and ore concentration is used to evaluate iron ore reserves in the deeper part of known ore fields. Further, similar analysis is made to nearby <span class="hlt">magnetically</span> anomalous areas covered by weakly <span class="hlt">magnetic</span> metasediments, to estimate potential ore reserves at unexposed formations.</p> <div class="credits"> <p class="dwt_author">Korhonen, Juha; Kukkonen, Ilmo</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-04-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_15");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" 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showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_18");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">321</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/41976604"> <span id="translatedtitle">A model of ocean basin crustal <span class="hlt">magnetization</span> appropriate for satellite elevation <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">A model of ocean basin crustal <span class="hlt">magnetization</span> measured at satellite altitudes is developed which will serve both as background to which anomalous <span class="hlt">magnetizations</span> can be contrasted and as a beginning point for studies of tectonic modification of normal ocean crust. The model is based on published data concerned with the petrology and <span class="hlt">magnetization</span> of the ocean crust and consists of</p> <div class="credits"> <p class="dwt_author">Herman H. Thomas</p> <p class="dwt_publisher"></p> <p class="publishDate">1987-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">322</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/5558840"> <span id="translatedtitle">Aeromagnetic <span class="hlt">anomalies</span> and discordant lineations beneath the Niger Delta: Implications for new fracture zones and multiple sea-floor <span class="hlt">spreading</span> directions in the meso-Atlantic' Gulf of Guinea cul-de-sac</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">An aeromagnetic contour map compiled over shallow water and onshore portions of the Nigerian continental margin, shows several elongate, long-wavelength <span class="hlt">anomaly</span> closures with some alternating polarity, separated by steep gradient, NE lineations. The lineations are interpreted as new fracture zones or extensions of previously mapped ones. The NE trend in the western delta region is concordant with the fracture zone trends of the deeper Gulf of Guinea. Aeromagnetic lineations of the SE Niger Delta Basin however, discordantly trend ENE. Their termination against the former, is interpreted as evidence of early sea-floor <span class="hlt">spreading</span> in a ENE-WSW direction in addition to the well documented NE-SW <span class="hlt">spreading</span> of the Gulf of Guinea and the rest of the meso-Atlantic sea-floor; The geophysical crustal structure indicate the existence of two Early Cretaceous triple junctions beneath the Niger Delta Basin. The two triple-junctions further support the hypothesis that the African continent was a multi-plate system (in the Niger Delta region) during the early opening of the Atlantic.</p> <div class="credits"> <p class="dwt_author">Babalola, O.O.; Gipson, M. Jr. (Univ. of South Carolina, Columbia (United States))</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">323</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40844080"> <span id="translatedtitle">Mesozoic <span class="hlt">magnetic</span> lineations in the Mozambique Basin</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">East-west-trending Mesozoic <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> M2 through M22 have been identified in the northern Mozambique Basin. These <span class="hlt">anomalies</span> are best matched by sea floor created at 50°S trending N120°E and <span class="hlt">spreading</span> at a rate of around 1.5 cm\\/yr. The northward increase in age inferred from the identifications of these <span class="hlt">anomalies</span> are compatible with observed decrease in the ``reliable'' heat flow values</p> <div class="credits"> <p class="dwt_author">E. S. W. Simpson; J. G. Sclater; B. Parsons; I. Norton; L. Meinke</p> <p class="dwt_publisher"></p> <p class="publishDate">1979-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">324</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFMGP41C..05G"> <span id="translatedtitle">Laboratory and Field Experiments to Better Understand <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> of Meteorite Impacts</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The thermal and tectonic history of planets can be gleaned from the ancient <span class="hlt">magnetic</span> fields recorded in their rock records. Because meteorite impacts alter the <span class="hlt">magnetic</span> signals of rocks, one can hope to work out an approximate <span class="hlt">magnetic</span> stratigraphy of a planet based on the relative timing of core dynamo activity versus the age of meteorite impact. Such is the common perception for Mars, whose giant impact craters, Hellas and Argyre, possess significantly lower <span class="hlt">magnetizations</span> than surrounding regions. The typical assumption is that rocks in the craters were shock demagnetized in the absence of a core dynamo. To test these assumptions and to better understand the effects of stress on the remanent <span class="hlt">magnetizations</span> of rocks, we have been carrying out both laboratory and field experiments. Here we report stress demagnetization experiments on single and multi-domain magnetite, the <span class="hlt">magnetic</span> mineral most likely to carry the <span class="hlt">magnetic</span> remanence on Mars. We also report paleomagnetic and geomagnetic measurements in the Vredefort crater, whose basement rocks carry magnetite as the remanence-bearing <span class="hlt">magnetic</span> mineral. We conclude that <span class="hlt">magnetic</span> fields fossilized in the rock record of meteorite impacts cannot be used to ascertain the presence or absence of a planet`s dynamo as previously assumed.</p> <div class="credits"> <p class="dwt_author">Gilder, S.; Le Goff, M.; Carporzen, L.; Hart, R. J.; Muundjua, M.; Galdeano, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">325</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/52373221"> <span id="translatedtitle">The <span class="hlt">Magnetic</span> Moment of K40 and the Hyperfine Structure <span class="hlt">Anomaly</span> of the Potassium Isotopes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The nuclear <span class="hlt">magnetic</span> moment and atomic hyperfine splitting of the rare K40 isotope have been measured by the atomic beam <span class="hlt">magnetic</span> resonance technique. Detection of K40 atoms, from a source of normal potassium, was achieved by employing a conventional surface ionization detector as the ion source for a mass spectrometer, and by utilizing an electron multiplier to count the K40</p> <div class="credits"> <p class="dwt_author">J. T. Eisinger; B. Bederson; B. T. Feld</p> <p class="dwt_publisher"></p> <p class="publishDate">1952-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">326</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19730012641&hterms=cosmos&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dcosmos"> <span id="translatedtitle">The detection of intermediate size <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in Cosmos-49 and OGO-2, 4, and 6 data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Benkova, Dolginov, and Simonenko have recently reported the presence of intermediate size <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the data from COSMOS-49 and hypothesized a crustal and/or upper mantle origin. The spherical harmonic models of the internal potential function were examined, based on the OGO-2, 4, and 6 data (POGO (10/68) and later models), and verified the locations and amplitudes of those <span class="hlt">anomalies</span> whose wavelengths approximate 4000 km. The comparison was made by subtracting a field model developed with a truncated series of n* = 9 from one computed with n* = 11 and generating a residual map equivalent to the COSMOS-49 data. The patterns of delta F so computed from POGO were then compared with the IZMIRAN maps and also were analyzed statistically, in both the spatial and frequency domains, using residuals computed from the raw COSMOS-49 data with the n* = 9 COSMOS-49 field model as reference. The two sets of data were thus derived from completely independent sets of observations and field references. The two patterns are shown to agree very well over the whole earth surface up to the 50 deg latitude limit of COSMOS-49.</p> <div class="credits"> <p class="dwt_author">Regan, R. D.; Davis, W. M.; Cain, J. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">1973-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">327</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012EGUGA..14.8983E"> <span id="translatedtitle">GMinterp, A Matlab Based Toolkit for Gravity and <span class="hlt">Magnetic</span> Data Analysis: Example Application to the Airborne <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> of Biga Peninsula, NW Turkey</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The analysis of gravity and <span class="hlt">magnetic</span> field methods is becoming increasingly significant for the earth sciences as a whole and these potential field methods efficiently assist in working out both shallow and deep geologic problems and play important role on modeling and interpretation procedures. The main advantage of some gravity and <span class="hlt">magnetic</span> data processing techniques is to present the subtle details in the data which are not clearly identified in <span class="hlt">anomaly</span> maps, without specifying any prior information about the nature of the source bodies. If the data quality permits, many analyzing techniques can be carried out that help to build a general understanding of the details and parameters of the shallower or deeper causative body distributions such as depth, thickness, lateral and vertical extensions. Gravity and <span class="hlt">magnetic</span> field data are usually analyzed by means of analytic signal (via directional derivatives) methods, linear transformations, regional and residual <span class="hlt">anomaly</span> separation techniques, spectral methods, filtering and forward and inverse modeling techniques. Some commercial software packages are commonly used for analyzing potential field data by employing some of the techniques specified above. Additionally, many freeware and open-source codes can be found in the literature, but unfortunately they are focused on special issues of the potential fields. In this study, a toolkit, that performs numerous interpretation and modeling techniques for potential field data, is presented. The toolkit, named GMinterp, is MATLAB-based consisting of a series of linked functions along with a graphical user interface (GUI). GMinterp allows performing complex processing such as transformations and filtering, editing, gridding, mapping, digitizing, extracting cross-sections, forward and inverse modeling and interpretation tasks. The toolkit enables to work with both profile and gridded data as an input file. Tests on the theoretically produced data showed the reliability of developed toolkit. Additionally some experiments on real data sets were performed to interpret the geological structure of Biga Peninsula, NW part of Anatolia, Turkey. Keywords: GMinterp, GUI, airborne <span class="hlt">magnetic</span> data, geology, Biga Peninsula</p> <div class="credits"> <p class="dwt_author">Ekinci, Y. L.; Yi?itba?, E.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">328</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820015737&hterms=July-September+1981&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2522July-September%2B1981%2522"> <span id="translatedtitle">Investigations of medium wavelength <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the eastern Pacific using MAGSAT</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Progress in study of the details of spherical harmonic representations of the Earth's <span class="hlt">magnetic</span> field is reported. The first of the Investigator B quiet time tapes were received and determined to be error free.</p> <div class="credits"> <p class="dwt_author">Harrison, C. G. A. (principal investigator)</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">329</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE95630902"> <span id="translatedtitle"><span class="hlt">Magnetization</span> <span class="hlt">anomalies</span> of fine particles interpreted as surface effects by inelastic neutron scattering.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Inelastic neutron scattering experiments on small Fe particles (R=12 Angstrom) reveal that some part of the <span class="hlt">magnetic</span> intensity is paramagnetic at 300 K. As T decreases it freezes and develops short range ferromagnetic correlations. It is attributed to spi...</p> <div class="credits"> <p class="dwt_author">M. Hennion I. Mirebeau C. Bellouard</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">330</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014Tectp.624...32B"> <span id="translatedtitle">The Wallula fault and tectonic framework of south-central Washington, as interpreted from <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Yakima fold and thrust belt (YFTB) in central Washington has accommodated regional, mostly north-directed, deformation of the Cascadia backarc since prior to emplacement of Miocene flood basalt of the Columbia River Basalt Group (CRBG). The YFTB consists of two structural domains. Northern folds of the YFTB strike eastward and terminate at the western margin of a 20-mGal negative gravity <span class="hlt">anomaly</span>, the Pasco gravity low, straddling the North American continental margin. Southern folds of the YFTB strike southeastward, form part of the Olympic-Wallowa lineament (OWL), and pass south of the Pasco gravity low as the Wallula fault zone. An upper crustal model based on gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> suggests that the Pasco gravity low is caused in part by an 8-km-deep Tertiary basin, the Pasco sub-basin, abutting the continental margin and concealed beneath CRBG. The Pasco sub-basin is crossed by north-northwest-striking <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> caused by dikes of the 8.5 Ma Ice Harbor Member of the CRBG. At their northern end, dikes connect with the eastern terminus of the Saddle Mountains thrust of the YFTB. At their southern end, dikes are disrupted by the Wallula fault zone. The episode of NE-SW extension that promoted Ice Harbor dike injection apparently involved strike-slip displacement on the Saddle Mountains and Wallula faults. The amount of lateral shear on the OWL impacts the level of seismic hazard in the Cascadia region. Ice Harbor dikes, as mapped with aeromagnetic data, are dextrally offset by the Wallula fault zone a total of 6.9 km. Assuming that dike offsets are tectonic in origin, the Wallula fault zone has experienced an average dextral shear of 0.8 mm/y since dike emplacement 8.5 Ma, consistent with right-lateral stream offsets observed at other locations along the OWL. Southeastward, the Wallula fault transfers strain to the north-striking Hite fault, the possible location of the M 5.7 Milton-Freewater earthquake in 1936.</p> <div class="credits"> <p class="dwt_author">Blakely, Richard J.; Sherrod, Brian L.; Weaver, Craig S.; Wells, Ray E.; Rohay, Alan C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">331</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/6888236"> <span id="translatedtitle">A source for the New York-Alabama <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in eastern Tennessee: Felsic intrusions concealed beneath the Paleozoic shelf strata</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Several vibroseis industry seismic lines have been reprocessed and recorrelated to obtain images from the deep crust. These lines straddle the New York-Alabama <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> and intersect it at approximately right angles. Beneath the Paleozoic shelf rocks within the crystalline crust a distinct wedge-shaped geometry appears in the data that opens up to the northeast and tapers to an apex near the steepest part of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. Two parallel reflection seismic profiles indicate that the wedge-shaped feature extends for at least 25 km in a NE-SW direction along the New York-Alabama <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. The data image a geometry that is bounded above by the Paleozoic rocks of the Cumberland plateau and Valley and Ridge provinces, and below by a west dipping contact between the interpreted felsic intrusion and adjacent rocks. The intrusion exhibits overall low reflectivity with faintly visible subhorizontal reflections. The crust southeast and beneath the body is characterized by high reflectivity and a strong west-dipping fabric. The contrast between the wedge and adjacent crust could result from the emplacement of the body following events that produced the west-dipping fabric. The gravity signature requires a negative density contrast between the interpreted felsic wedge and the adjacent crust, the density of the wedge being lower. The <span class="hlt">magnetic</span> signature can be interpreted to indicate that the wedge has a higher susceptibility than adjacent crust. The potential field data are consistent with the interpretation of a granitic wedge that is accompanied by a contact aureole of even higher <span class="hlt">magnetic</span> susceptibility. The authors propose that felsic intrusions, possibly with contact aureoles, are responsible for at least part of the strong New York-Alabama <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. The striking linearity of the <span class="hlt">anomaly</span> suggests tectonic control on the emplacement of the intrusions.</p> <div class="credits"> <p class="dwt_author">Hopkins, D.L.; Costain, J.K. (Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Dept. of Geological Sciences); Zietz, I. (George Mason Univ., Fairfax, VA (United States). Inst. of Geography and Geology)</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-03-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">332</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2007GeoJI.168..983J"> <span id="translatedtitle">Geophysical characteristics of the ultraslow <span class="hlt">spreading</span> Gakkel Ridge, Arctic Ocean</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The northernmost <span class="hlt">spreading</span> centre of the world, the Gakkel Ridge, is also an end-member in terms of global <span class="hlt">spreading</span> velocities. Models show that full <span class="hlt">spreading</span> rates vary between 1.3 and 0.63 mm yr-1 along the almost 1800 km long ridge system in the Central Arctic Ocean. The western part of the ridge was investigated in great detail by a two-ship expedition in summer 2001. The complete data sets and the modelling of the seismic refraction and aeromagnetic experiments gathered during this expedition are shown in this study. The <span class="hlt">magnetic</span> signals along the dense (2 km spacing) aeromagnetic flight lines acquired at the same time show a good correlation between high amplitudes and a shallowing of the rift valley and the presence of large volcanic constructions at the rift shoulders. The <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> rapidly fade out east and west of these centres of focused magmatism. This might indicate that the basaltic layer producing the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> thins away from the volcanic centres. A continuous <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> is observed along the rift valley west of 3°30'E, consistent with increasing and more robust magmatism. The crustal thickness along the Gakkel Ridge varies greatly. Beneath some of the centres of focused magmatism, the oceanic crust thickens up to 3.5 km. In the amagmatic segments in between the crust thins to 1.4-2.9 km. This observation is also valid for the Western Volcanic Zone west of 3°30'E, where despite the stronger <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> the crust does not significantly thicken. The strength of the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> along the rift valley is thus not a reliable indicator of crustal thickness beneath the Gakkel Ridge. The data show that the crustal thickness does not change dramatically across 3°30'E. Only the occurrence of a large elongate volcanic ridge significantly influences this parameter. More frequent volcanic eruptions along such ridges are most likely responsible for the basalts found in the westernmost part of the Gakkel Ridge. In the non-transform segments some seismic stations indicate that mantle rocks are exposed at the seafloor, with no indication of the presence of a basaltic cover or normal oceanic crust. Both the seismic and <span class="hlt">magnetic</span> data support models in which the uppermost basaltic cover is responsible for the <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> in the rift valley.</p> <div class="credits"> <p class="dwt_author">Jokat, Wilfried; Schmidt-Aursch, Mechita C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">333</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://dx.doi.org/10.1016/j.tecto.2008.09.006"> <span id="translatedtitle">The Mackenzie River <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>, Yukon and Northwest Territories, Canada-Evidence for Early Proterozoic magmatic arc crust at the edge of the North American craton</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p class="result-summary">We characterize the nature of the source of the high-amplitude, long-wavelength, Mackenzie River <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> (MRA), Yukon and Northwest Territories, Canada, based on <span class="hlt">magnetic</span> field data collected at three different altitudes: 300??m, 3.5??km and 400??km. The MRA is the largest amplitude (13??nT) satellite <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> over Canada. Within the extent of the MRA, source depth estimates (8-12??km) from Euler deconvolution of low-altitude aeromagnetic data show coincidence with basement depths interpreted from reflection seismic data. Inversion of high-altitude (3.5??km) aeromagnetic data produces an average <span class="hlt">magnetization</span> of 2.5??A/m within a 15- to 35-km deep layer, a value typical of magmatic arc complexes. Early Proterozoic magmatic arc rocks have been sampled to the southeast of the MRA, within the Fort Simpson <span class="hlt">magnetic</span> <span class="hlt">anomaly</span>. The MRA is one of several broad-scale <span class="hlt">magnetic</span> highs that occur along the inboard margin of the Cordillera in Canada and Alaska, which are coincident with geometric changes in the thrust front transition from the mobile belt to stable cratonic North America. The inferred early Proterozoic magmatic arc complex along the western edge of the North American craton likely influenced later tectonic evolution, by acting as a buttress along the inboard margin of the Cordilleran fold-and-thrust belt. Crown Copyright ?? 2008.</p> <div class="credits"> <p class="dwt_author">Pilkington, M.; Saltus, R. W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">334</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2000mpse.conf...30E"> <span id="translatedtitle">An Assessment of the North Polar <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span>: Implications for Basal Melting and Polar Wander</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Measurements taken by the magnetometers aboard Mars Global Surveyor (MGS) during aerobraking have provided the most spatially complete mapping of the radial <span class="hlt">magnetic</span> field (Br) in the Mars North Polar Region (NPR) available to date. The subsequent map made of this complete coverage depicts an anomalous region of relatively strong field intensity (approx. +/- 40nT) in addition to the more isotropically distributed regions of (approx. +/- lOnT). This analysis explores the possible connection between liquid water environments in the NPR and reinforcement of <span class="hlt">magnetized</span> regions. Additional information is contained in original extended abstract.</p> <div class="credits"> <p class="dwt_author">Eckberg, J. T.</p> <p class="dwt_publisher"></p> <p class="publishDate">2000-08-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">335</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2006cosp...36.2796S"> <span id="translatedtitle">Comparison of the dynamics and structure of Saturn and Jupiter magnetospheres: camshaft, <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> and corotating convection models compared.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Scenarios are presented for the overall flux and mass circulation in the jovian and saturnian magnetospheres It is argued that similar fundamanetal processes underly the dynamical processes at both planets However the differences in parameter regime for the two systems leads to substantial resulting differences in morphology Transport is accomplished from the inner magnetosphere by interchange motion which then feeds into the outer magnetosphere where ballooning driven by centrifugal stress leads to field reconnection and plasma loss It seems likely that Jupiter loses much more material per rotation cycle than Saturn and is possibly much more symmetrically loaded in respect of planetary longitude Material loss and flux return at Jupiter have fixed orientations in local time early evening and morning sector respectively and newly returned flux is probably responsible for the morningside cushion region in the outer magnetosphere At Jupiter the dawn-dusk asymmetry in the current sheet thin in morning thick in afternoon is also a dominant feature At Saturn there seems no evidence of a cushion region flux return is thought to take place sporadically over much of the nightside Although definitive statements about the dusk plasma sheet await the orbit evolution of Cassini a fundamental observational feature in the Saturnian context is a planetary rotation induced <span class="hlt">magnetic</span> field asymmetry which argues against major dawn-dusk asymmetry We propose the rotational feature could originate from a localized ionospheric <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> The</p> <div class="credits"> <p class="dwt_author">Southwood, D. J.; Kivelson, M. G.</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">336</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56400557"> <span id="translatedtitle">A Least-squares Window Curves Method for Interpretation of <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Caused by Dipping Dikes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have developed a least-squares method to determine simultaneously the depth and the width of a buried thick dipping dike from residualized <span class="hlt">magnetic</span> data using filters of successive window lengths. The method involves using a relationship between the depth and the half-width of the source and a combination of windowed observations. The relationship represents a family of curves (window curves).</p> <div class="credits"> <p class="dwt_author">E. M. Abdelrahman; E. R. Abo-Ezz; K. S. Soliman; T. M. El-Araby; K. S. Essa</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">337</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/51172547"> <span id="translatedtitle"><span class="hlt">Magnetization</span> <span class="hlt">Anomaly</span> of Nb3Al Strands and Instability of Nb3Al Rutherford Cables</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Using a Cu stabilized strand with Nb matrix, a 30 meter long Rutherford cable was made by a collaboration of Fermilab and NIMS. Recently the strand and cable were tested. In both cases instability was observed at around 1.5 Tesla. The <span class="hlt">magnetization</span> of this strand was measured first using a balanced coil magnetometer at 4.2 K. Strands showed an anomalously</p> <div class="credits"> <p class="dwt_author">Ryuji Yamada; Akihiro Kikuchi; Masayoshi Wake</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">338</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56032560"> <span id="translatedtitle"><span class="hlt">Magnetic</span> <span class="hlt">anomalies</span> and tectonic fabric of marginal basins North of New Zealand</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Detailed airborne <span class="hlt">magnetic</span> studies conducted over the region of the S. W. Pacific marginal basins extending from the Solomon Islands to New Zealand suggest that three major phases of basin formation and island arc development have occurred in this region. Development of the Tasman Sea took place during the Late Cretaceous-Paleocene. Development of the basins to the east of the</p> <div class="credits"> <p class="dwt_author">Alexander Malahoff; Robert H. Feden; Henry S. Fleming</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">339</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/t84wv50773489285.pdf"> <span id="translatedtitle">Interpretation of gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> when observation plane is inclined</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Not infrequently, in mining geophysics, measurements have to be made on the slopes of a hill that contain mineralisation. In this paper, procedures are evolved for interpreting gravity and vertical component <span class="hlt">magnetic</span> data collected on such slopes and caused by geological bodies that can be approximated by infinite line pole, point pole, infinite line dipole and point dipole. From sets</p> <div class="credits"> <p class="dwt_author">M. V. Ramanaiah Chowdary; A. Roy</p> <p class="dwt_publisher"></p> <p class="publishDate">1969-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">340</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://eric.ed.gov/?q=geomagnetic+AND+reversal&id=EJ386134"> <span id="translatedtitle">An Exercise on <span class="hlt">Magnetic-Anomaly</span> Profiles and the Geomagnetic Polar-Reversal Time Scale.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p class="result-summary">Develops an exercise in which students use <span class="hlt">magnetic</span>-profile data gathered in the South Pacific to test the Vine-Matthews-Morley hypothesis. Uses the Eltanin 19N and 20N profiles. Relates the exercise to 20 current geology texts. (MVL)</p> <div class="credits"> <p class="dwt_author">Shea, James Herbert</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_16");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return 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<a onClick='return showDiv("page_11");' href="#">11</a> <a onClick='return showDiv("page_12");' href="#">12</a> <a onClick='return showDiv("page_13");' href="#">13</a> <a onClick='return showDiv("page_14");' href="#">14</a> <a onClick='return showDiv("page_15");' href="#">15</a> <a onClick='return showDiv("page_16");' href="#">16</a> <a onClick='return showDiv("page_17");' href="#">17</a> <a style="font-weight: bold;">18</a> <a onClick='return showDiv("page_19");' href="#">19</a> <a onClick='return showDiv("page_20");' href="#">20</a> <a onClick='return showDiv("page_21");' href="#">21</a> <a onClick='return showDiv("page_22");' href="#">22</a> <a onClick='return showDiv("page_23");' href="#">23</a> <a onClick='return showDiv("page_24");' href="#">24</a> <a onClick='return showDiv("page_25");' href="#">25</a> </span> </span> <a id="NextPageLink" onclick='return showDiv("page_19");' href="#" title="Next Page"> <img id="NextPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">341</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/54562751"> <span id="translatedtitle">Marine <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> Compilations in the Indian Ocean for Plate Tectonics and Beyond (Invited)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The French territories in the western and southern parts of the Indian Ocean (i.e. Reunion and Mayotte islands, islands in the Mozambique Channel, Kerguelen and Crozet archipelagos, Saint Paul and Amsterdam islands...) have triggered significant scientific activities, including marine geophysics, by French scientists in this area. French marine <span class="hlt">magnetic</span> data in this ocean span more than four decades, with records</p> <div class="credits"> <p class="dwt_author">J. Dyment; G. C. Bhattacharya; Y. Vadakkeyakath; D. Bissessur; J. Jacob; K. R. Kattoju; T. Ramprasad; J. Royer; P. Patriat; A. K. Chaubey; K. Srinivas; Y. Choi</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">342</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/qg74213301495567.pdf"> <span id="translatedtitle">A Least-squares Window Curves Method for Interpretation of <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> Caused by Dipping Dikes</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">We have developed a least-squares method to determine simultaneously the depth and the width of a buried thick dipping dike\\u000a from residualized <span class="hlt">magnetic</span> data using filters of successive window lengths. The method involves using a relationship between\\u000a the depth and the half-width of the source and a combination of windowed observations. The relationship represents a family\\u000a of curves (window curves).</p> <div class="credits"> <p class="dwt_author">E. M. Abdelrahman; E. R. Abo-Ezz; K. S. Soliman; T. M. El-Araby; K. S. Essa</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">343</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60686134"> <span id="translatedtitle"><span class="hlt">Magnetization</span> <span class="hlt">anomaly</span> of Nb3Al strands and instability of Nb3Al Rutherford cables</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Using a Cu stabilized NbAl strand with Nb matrix, a 30 meter long NbAl Rutherford cable was made by a collaboration of Fermilab and NIMS. Recently the strand and cable were tested. In both cases instability was observed at around 1.5 Tesla. The <span class="hlt">magnetization</span> of this NbAl strand was measured first using a balanced coil magnetometer at 4.2 K. Strands</p> <div class="credits"> <p class="dwt_author">Ryuji Yamada; Akihiro Kikuchi; Masayoshi Wake</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">344</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19910053842&hterms=MAGNESIUM&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DMAGNESIUM"> <span id="translatedtitle">Positive holes in magnesium oxide - Correlation between <span class="hlt">magnetic</span>, electric, and dielectric <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">The present <span class="hlt">magnetic</span> susceptibility investigation of high purity MgO single crystals notes an anomally at 800 K which is associated with increasing electrical conductivity, a rise in static dielectric constant from 9 to 150, and the appearance of a pronounced positive surface charge. These phenomena can be accounted for in terms of peroxy defects which represent self-trapped, spin-paired positive holes at Mg(2+) vacancy sites. The holes begin to decouple their spins above 600 K.</p> <div class="credits"> <p class="dwt_author">Batllo, F.; Leroy, R. C.; Parvin, K.; Freund, F.; Freund, M. M.</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">345</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18290453"> <span id="translatedtitle">Heat capacity <span class="hlt">anomaly</span> of CeCu 2.05Si 2 under <span class="hlt">magnetic</span> fields</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Heat capacity measurements of CeCu2.05Si2 have been carried out at temperatures down to 0.1 K under <span class="hlt">magnetic</span> field up to 13 T. The heat capacity divided by temperature C\\/T has revealed as a characteristic feature that the peak of C\\/T shifts down to around 0.5 K with increasing field up to 7 T, whereafter it shifts up again to around</p> <div class="credits"> <p class="dwt_author">T. C. Kobayashi; A. Koda; H. Honda; K. Amaya; Y. Kitaoka; K. Asayama; C. Geibel; F. Steglich</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">346</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18461005"> <span id="translatedtitle"><span class="hlt">Magnetic</span> and transport eddy-current <span class="hlt">anomalies</span> in cylinders with core-and-shell regions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">For a conducting <span class="hlt">magnetic</span> cylinder of radius r0, conductivity ?, and regionally uniform DC permeabilities ?c,?s, and ?b in the core, the shell, and the core–shell border at r=rb<r0, the complex AC permeability ? and impedance Z are calculated analytically from the Maxwell equations and the Ohm law. Compared with the results of the classical models with uniform local DC</p> <div class="credits"> <p class="dwt_author">D.-X. Chen; L. Pascual; E. Fraga; M. Vazquez; A. Hernando</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">347</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUFMGP33B..03D"> <span id="translatedtitle">Toward a minimum change model for recent plate motions: Calibrating seafloor <span class="hlt">spreading</span> rates for outward displacement</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We use seafloor <span class="hlt">spreading</span> distances derived from dense <span class="hlt">magnetic</span> surveys of young <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> flanking seven seafloor <span class="hlt">spreading</span> centers and the velocities of 398 continuous GPS sites on the plates bordering these <span class="hlt">spreading</span> centers to study outward displacement, a phenomenon in which seafloor <span class="hlt">spreading</span> <span class="hlt">magnetic</span> lineations are displaced outward from their idealized locations as a consequence of extrusive and intrusive emplacement of new magma across a several-km-wide zone centered on the <span class="hlt">spreading</span> axis and outward sloping reversal boundaries. Linear regressions of age-opening distance series derived from crossings of <span class="hlt">magnetic</span> reversals 1n-3An.2 (0.78 Ma-6.72 Ma) yield positive Y-intercepts for 42 out of 53 seafloor <span class="hlt">spreading</span> segments, corresponding to displacement of reversals outward from the seafloor <span class="hlt">spreading</span> axis. The improvement in the least-squares fit of a model that allows for outward displacement relative to a model in which outward displacement is assumed to be zero is significant at a very high confidence level. Separate inversions of 13 age-distance series derived from <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> crossings grouped by plate boundary yields 12 estimates of outward displacement that range from 0.5-3 km and unusually wide outward displacement of 6.1+-0.4 km along the Reykjanes Ridge. Detailed analysis of numerous crossings of <span class="hlt">Anomaly</span> 1n from the Southeast Indian ridge suggests there is a correlation between axial morphology and the magnitude of outward displacement; however, too few data are available from axial rise segments along other seafloor <span class="hlt">spreading</span> centers to confirm whether this correlation is characteristic of other seafloor <span class="hlt">spreading</span> centers. Our results corroborate previous estimates of <span class="hlt">magnetic</span> polarity transition zone widths derived from near-bottom <span class="hlt">magnetic</span> measurements, which range from 1-8 km and average 2 km. Statistical tests of our age-distance series indicate that all but two are consistent within errors with a globally averaged value for outward displacement of 1.9+-0.2 km. Seafloor <span class="hlt">spreading</span> rates corrected for outward displacement agree better with instantaneous rates estimated from GPS-derived plate angular velocity vectors than do uncorrected long-term rates, underscoring the need to correct seafloor <span class="hlt">spreading</span> rates for outward displacement before attempting to interpret differences between geodetic and geologic estimates of plate motions.</p> <div class="credits"> <p class="dwt_author">Demets, C.; Wilson, D. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">348</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2005AGUSM.G24A..01D"> <span id="translatedtitle">Toward a Minimum Change Model for Recent Plate Motions: Calibrating Seafloor <span class="hlt">Spreading</span> Rates for Outward Displacement</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We use seafloor <span class="hlt">spreading</span> distances derived from dense <span class="hlt">magnetic</span> surveys of young <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> flanking seven seafloor <span class="hlt">spreading</span> centers and the velocities of 398 continuous GPS sites on the plates bordering these <span class="hlt">spreading</span> centers to study outward displacement, a phenomenon in which seafloor <span class="hlt">spreading</span> <span class="hlt">magnetic</span> lineations are displaced outward from their idealized locations as a consequence of extrusive and intrusive emplacement of new magma across a several-km-wide zone centered on the <span class="hlt">spreading</span> axis and outward sloping reversal boundaries. Linear regressions of age-opening distance series derived from crossings of <span class="hlt">magnetic</span> reversals 1n-3An.2 (0.78 Ma-6.72 Ma) yield positive Y-intercepts for 42 out of 53 seafloor <span class="hlt">spreading</span> segments, corresponding to displacement of reversals outward from the seafloor <span class="hlt">spreading</span> axis. The improvement in the least-squares fit of a model that allows for outward displacement relative to a model in which outward displacement is assumed to be zero is significant at a very high confidence level. Separate inversions of 13 age-distance series derived from <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> crossings grouped by plate boundary yields 12 estimates of outward displacement that range from 0.5-3 km and unusually wide outward displacement of 6.1+-0.4 km along the Reykjanes Ridge. Detailed analysis of numerous crossings of <span class="hlt">Anomaly</span> 1n from the Southeast Indian ridge suggests there is a correlation between axial morphology and the magnitude of outward displacement; however, too few data are available from axial rise segments along other seafloor <span class="hlt">spreading</span> centers to confirm whether this correlation is characteristic of other seafloor <span class="hlt">spreading</span> centers. Our results corroborate previous estimates of <span class="hlt">magnetic</span> polarity transition zone widths derived from near-bottom <span class="hlt">magnetic</span> measurements, which range from 1-8 km and average 2 km. Statistical tests of our age-distance series indicate that all but two are consistent within errors with a globally averaged value for outward displacement of 1.9+-0.2 km. Seafloor <span class="hlt">spreading</span> rates corrected for outward displacement agree better with instantaneous rates estimated from GPS-derived plate angular velocity vectors than do uncorrected long-term rates, underscoring the need to correct seafloor <span class="hlt">spreading</span> rates for outward displacement before attempting to interpret differences between geodetic and geologic estimates of plate motions.</p> <div class="credits"> <p class="dwt_author">Demets, C.; Wilson, D. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">349</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48950486"> <span id="translatedtitle">Ridge segmentation and the <span class="hlt">magnetic</span> structure of the Southwest Indian Ridge (at 50°30?E, 55°30?E and 66°20?E): Implications for magmatic processes at ultraslow-<span class="hlt">spreading</span> centers</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The aim of this paper is to investigate the relationships between the segmentation and the <span class="hlt">magnetic</span> structure of the ultraslow-<span class="hlt">spreading</span> Southwest Indian Ridge. Contrary to faster <span class="hlt">spreading</span> ridges, <span class="hlt">magnetization</span> usually decreases from high values along the neovolcanic axis to low values in the nontransform discontinuities. There is a direct correlation between the deepening of the axial valley and the decrease</p> <div class="credits"> <p class="dwt_author">Daniel Sauter; Hélène Carton; Véronique Mendel; Marc Munschy; Céline Rommevaux-Jestin; Jean-Jacques Schott; Hubert Whitechurch</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">350</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014Tectp.624...24M"> <span id="translatedtitle">Remanent <span class="hlt">magnetization</span> in fresh xenoliths derived from combined demagnetization experiments: <span class="hlt">Magnetic</span> mineralogy, origin and implications for mantle sources of <span class="hlt">magnetic</span> <span class="hlt">anomalies</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Fresh mantle xenoliths represent an exceptional opportunity to directly access Earth's interior. In particular, <span class="hlt">magnetic</span> signals carried by upper mantle xenoliths may provide the only opportunity to determine the depth of remanent <span class="hlt">magnetization</span> below the Moho boundary. In recent years, the nature, intensity and <span class="hlt">magnetic</span> properties of the <span class="hlt">magnetic</span> signal have been characterized by measurements of the 0020 induced <span class="hlt">magnetization</span> in hysteresis loops. The natural remanent <span class="hlt">magnetization</span> (NRM) intensity, despite providing the first indication of the <span class="hlt">magnetic</span> nature of magnetite inclusions, has not been studied in detail. This study focusses attention on the number of recorded NRM directions and characteristics of the anhysteretic remanent <span class="hlt">magnetization</span> (ARM) and saturation isothermal remanent <span class="hlt">magnetization</span> (SIRM) demagnetization spectra. A collection of 17 extremely fresh mantle xenoliths has been subjected to AF demagnetization, characterizing samples with one, two or three populations of remanence carriers, with differing coercivities, that are potential carriers of <span class="hlt">magnetization</span> at mantle depths.</p> <div class="credits"> <p class="dwt_author">Martin-Hernandez, Fatima; Ferré, Eric C.; Friedman, Sarah A.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-06-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">351</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820016723&hterms=atlantic+drift+continental&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Datlantic%2Bdrift%2Bcontinental"> <span id="translatedtitle">MAGSAT <span class="hlt">anomaly</span> map and continental drift</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><span class="hlt">Anomaly</span> maps of high quality are needed to display unambiguously the so called long wave length <span class="hlt">anomalies</span>. The <span class="hlt">anomalies</span> were analyzed in terms of continental drift and the nature of their sources is discussed. The map presented confirms the thinness of the oceanic <span class="hlt">magnetized</span> layer. Continental <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> are characterized by elongated structures generally of east-west trend. Paleomagnetic reconstruction shows that the <span class="hlt">anomalies</span> found in India, Australia, and Antarctic exhibit a fair consistency with the African <span class="hlt">anomalies</span>. It is also shown that <span class="hlt">anomalies</span> are locked under the continents and have a fixed geometry.</p> <div class="credits"> <p class="dwt_author">Lemouel, J. L. (principal investigator); Galdeano, A.; Ducruix, J.</p> <p class="dwt_publisher"></p> <p class="publishDate">1981-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">352</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013NHESS..13..597C"> <span id="translatedtitle">Evaluation of seismo-electric <span class="hlt">anomalies</span> using <span class="hlt">magnetic</span> data in Taiwan</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Parkinson vectors derived from 3-component geomagnetic data via the <span class="hlt">magnetic</span> transfer function are discussed with respect to epicentre locations and hypocentre depths of 16 earthquakes (M ? 5.5) in Taiwan during a period of 2002-2005. To find out whether electric conductivity changes would happen particularly in the seismoactive depth ranges, i.e. in the vicinity of the earthquake foci, the frequency dependent penetration depth of the electromagnetic waves (skin effect) is taken into account. The background distributions involving the general conductivity structure and the coast effect at 20 particular depths are constructed using the Parkinson vectors during the entire study period. The background distributions are subtracted from the time-varying monitor distributions, which are computed using the Parkinson vectors within the 15-day moving window, to remove responses of the coast effect and underlying conductivity structure. Anomalous depth sections are identified by deviating distributions and agree with the hypocentre depths of 15 thrust and/or strike-slip earthquakes with only one exception of a normal fault event.</p> <div class="credits"> <p class="dwt_author">Chen, C. H.; Hsu, H. L.; Wen, S.; Yeh, T. K.; Chang, F. Y.; Wang, C. H.; Liu, J. Y.; Sun, Y. Y.; Hattori, K.; Yen, H. Y.; Han, P.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-03-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">353</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AGUFM.T51E2387Z"> <span id="translatedtitle">Basement and crustal structure from <span class="hlt">magnetic</span> and gravity <span class="hlt">anomalies</span> in the Songpan-Garzê and adjacent areas, China</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Songpan-Garzê orogenic belt is located in the eastern part of the Tibetan Plateau and west of the Sichuan basin. It is bounded by the South China, North China, Kunlun-Qaidam and Qiangtang (North Tibet) continental blocks. To the east, the Longmen Shan thrust-nappe belt separates the Songpan-Garzê fold belt from the Sichuan basin. The Songpan-Garzê basin and adjacent area are filled with a thick sequence of Triassic flyschoid sedimentary rocks. Within the Songpan-Garzê area, the Neoproterozoic basement only crops out in the southern part, in the Danba antiformal structure and to the east, along the Longmen-Shan belt, in the Xuelongbao metamorphic complex. To the north, below the Triassic sedimentary rocks, the nature of the basement (oceanic or continental) remains unknown. In order to research the range and the affinity of the basement of Songpan-Garzê orogenic belt, we ascertain the distribution range of the basement of Songpan-Garzê orogenic belt with aeromagnetic and seismic data, and discuss the affinity of the basement of the Songpan-Garzê orogenic belt with the geochemical data. Before identifying the boundaries of the basement we reduced the <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> to pole and continued them upward. The results show that the basement in Songpan-Ganzi areas belongs to Yangzi block. The boundaries are Erdaogou-Yushu-Litang in the west-south, Qingchuan-Dujiangyan in the east, and the line of southern Kunlun to Xinghai-Xiahe-Xihe. Under the restrictions of deep seismic sounding and rock density characteristics, we calculate the density structure of the crust across the Songpan-Garzê orogenic belt and adjacent areas along the gravity profile A-A', which trends 400NE. The density model of the crust in this area is divided into two parts, upper and lower crust, vertically. The depth of the Moho is about 62 km in the southwest, and 54 km in the northeast. This model shows that gravity isostasy obeys the Airy theory approximately within the Songpan-Garzê orogenic belt although a buried load in the bottom of lower crust. While a buried load remain beneath the Moho to the north of Songpan-Garzê orogenic belt. During constructing these buried loads we computed local decompensative gravity <span class="hlt">anomalies</span> on the condition that the depth of the lithospheric bottom is 120km. This work was supported by Crust Probe Project of China (SINOPROBE-02, SINOPROBE-08-02), the Natural Science Foundation of China (Nos. 40830316, 40774026, 40874045 ), China Geological Survey (Nos. 1212010611809, 1212010711813, 1212010811033), and scientific research project for public welfare from the Ministry of Land and Resources of China (No. 200811021,201011042).</p> <div class="credits"> <p class="dwt_author">Zhang, J.; Gao, R.; Li, Q.; Zhang, S.; Guan, Y.; Wang, H.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">354</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/44280959"> <span id="translatedtitle">Physicochemical formation conditions of banded iron formations and high-grade iron ores in the region of the Kursk <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span>: Evidence from isotopic data</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The oxygen and carbon isotopic compositions of minerals from banded iron formations (BIFs) and high-grade ore in the region\\u000a of the Kursk <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (KMA) were determined in order to estimate the temperature of regional metamorphism and the\\u000a nature of rock-and ore-forming solutions. Magnetite and hematite of primary sedimentary or diagenetic origin have ?18O within the range from +2 to</p> <div class="credits"> <p class="dwt_author">V. I. Belykh; E. I. Dunai; I. P. Lugovaya</p> <p class="dwt_publisher"></p> <p class="publishDate">2007-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">355</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013AGUFMGP51C1094S"> <span id="translatedtitle">Gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> used to delineate geologic features associated with earthquakes and aftershocks in the central Virginia seismic zone</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Estimating seismic hazard in intraplate environments can be challenging partly because events are relatively rare and associated data thus limited. Additionally, in areas such as the central Virginia seismic zone, numerous pre-existing faults may or may not be candidates for modern tectonic activity, and other faults may not have been mapped. It is thus important to determine whether or not specific geologic features are associated with seismic events. Geophysical and geologic data collected in response to the Mw5.8 August 23, 2011 central Virginia earthquake provide excellent tools for this purpose. Portable seismographs deployed within days of the main shock showed a series of aftershocks mostly occurring at depths of 3-8 km along a southeast-dipping tabular zone ~10 km long, interpreted as the causative fault or fault zone. These instruments also recorded shallow (< 4 km) aftershocks clustered in several areas at distances of ~2-15 km from the main fault zone. We use new airborne geophysical surveys (gravity, <span class="hlt">magnetics</span>, radiometrics, and LiDAR) to delineate the distribution of various surface and subsurface geologic features of interest in areas where the earthquake and aftershocks took place. The main (causative fault) aftershock cluster coincides with a linear, NE-trending gravity gradient (~ 2 mgal/km) that extends over 20 km in either direction from the Mw5.8 epicenter. Gravity modeling incorporating seismic estimates of Moho variations suggests the presence of a shallow low-density body overlying the main aftershock cluster, placing it within the upper 2-4 km of the main-fault hanging wall. The gravity, <span class="hlt">magnetic</span>, and radiometric data also show a bend in generally NE-SW orientation of <span class="hlt">anomalies</span> close to the Mw5.8 epicenter. Most shallow aftershock clusters occur near weaker short-wavelength gravity gradients of one to several km length. In several cases these gradients correspond to geologic contacts mapped at the surface. Along the gravity gradients, the aftershocks appear to cluster near areas with cross-cutting geologic features such as Jurassic diabase dikes. These associations suggest that local variations in rock density and/or rheology may have contributed to modifications of local stress regimes in a manner encouraging localized seismicity associated with the Mw5.8 event and its aftershocks. Such associations are comparable to results of previous studies recognizing correspondences between seismicity and features such as intrusive bodies and failed rifts in the New Madrid seismic zone and elsewhere. To explore whether similar correspondences may have occurred in the past, we use regional gravity and <span class="hlt">magnetic</span> data to consider possible relations between historical earthquakes and comparable geologic features elsewhere in the central Virginia seismic zone.</p> <div class="credits"> <p class="dwt_author">Shah, A. K.; Horton, J.; McNamara, D. E.; Spears, D.; Burton, W. C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">356</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=N8728236"> <span id="translatedtitle">Estudo Comparativo dos Efeitos de Tempestades Magneticas Em VLF na Anomalia Magnetica Do Atlantico Sul (Comparative Study of the Effects of <span class="hlt">Magnetic</span> Storms within VLF (Very Low Frequencies) on the <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span> of the South Atlantic).</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Effects produced in the lower ionosphere by forty <span class="hlt">magnetic</span> storms were analyzed in the period of 1976 to 1981. Using VLF propagation path omega-Argentina/Atibaia, which is located in the Brazilian Geomagnetic <span class="hlt">Anomaly</span>. Some storm effects which occurred in ...</p> <div class="credits"> <p class="dwt_author">N. M. Paesleme</p> <p class="dwt_publisher"></p> <p class="publishDate">1986-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">357</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3857849"> <span id="translatedtitle">Reconstructing Coherent Networks from Electroencephalography and Magnetoencephalography with Reduced Contamination from Volume Conduction or <span class="hlt">Magnetic</span> Field <span class="hlt">Spread</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Volume conduction (VC) and <span class="hlt">magnetic</span> field <span class="hlt">spread</span> (MFS) induce spurious correlations between EEG/MEG sensors, such that the estimation of functional networks from scalp recordings is inaccurate. Imaginary coherency [1] reduces VC/MFS artefacts between sensors by assuming that instantaneous interactions are caused predominantly by VC/MFS and do not contribute to the imaginary part of the cross-spectral densities (CSDs). We propose an adaptation of the dynamic imaging of coherent sources (DICS) [2] - a method for reconstructing the CSDs between sources, and subsequently inferring functional connectivity based on coherences between those sources. Firstly, we reformulate the principle of imaginary coherency by performing an eigenvector decomposition of the imaginary part of the CSD to estimate the power that only contributes to the non-zero phase-lagged (NZPL) interactions. Secondly, we construct an NZPL-optimised spatial filter with two a priori assumptions: (1) that only NZPL interactions exist at the source level and (2) the NZPL CSD at the sensor level is a good approximation of the projected source NZPL CSDs. We compare the performance of the NZPL method to the standard method by reconstructing a coherent network from simulated EEG/MEG recordings. We demonstrate that, as long as there are phase differences between the sources, the NZPL method reliably detects the underlying networks from EEG and MEG. We show that the method is also robust to very small phase lags, noise from phase jitter, and is less sensitive to regularisation parameters. The method is applied to a human dataset to infer parts of a coherent network underpinning face recognition.</p> <div class="credits"> <p class="dwt_author">Drakesmith, Mark; El-Deredy, Wael; Welbourne, Stephen</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">358</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3995527"> <span id="translatedtitle">The association between cerebral developmental venous <span class="hlt">anomaly</span> and concomitant cavernous malformation: an observational study using <span class="hlt">magnetic</span> resonance imaging</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p class="result-summary">Background Some studies reported that cerebral developmental venous <span class="hlt">anomaly</span> (DVA) is often concurrent with cavernous malformation (CM). But there is lack of statistical evidence and study of bulk cases. The factors associated with concurrency are still unknown. The purpose of this study was to determine the prevalence of concomitant DVA and CM using observational data on Chinese patients and analyze the factors associated with the concurrency. Methods The records of all cranial <span class="hlt">magnetic</span> resonance imaging (MRI) performed between January 2001 and December 2012 in Beijing Tiantan Hospital were reviewed retrospectively. The DVA and CM cases were selected according to imaging reports that met diagnostic criteria. Statistical analysis was performed using the Pearson chi-square statistic for binary variables and multivariable logistic regression analysis for predictors associated with the concurrent CM. Results We reviewed a total of 165,230 cranial MR images performed during the previous 12 year period, and identified 1,839 cases that met DVA radiographic criteria. There were 205 patients who presented concomitant CM among the 1,839 DVAs. The CM prevalence in DVA cases (11.1%) was significantly higher than that in the non-DVA cases (2.3%) (P<0.01). In the multivariate analysis, we found that DVAs with three or more medullary veins in the same MRI section (adjusted OR?=?2.37, 95% CI: 1.73-3.24), infratentorial DVAs (adjusted OR?=?1.71, 95% CI: 1.26-2.33) and multiple DVAs (adjusted OR?=?2.08, 95% CI: 1.04-4.16) have a higher likelihood of being concomitant with CM. Conclusions CM are prone to coexisting with DVA. There is a higher chance of concurrent CM with DVA when the DVA has three or more medullary veins in the same MRI scanning section, when the DVA is infratentorial, and when there are multiple DVAs. When diagnosing DVA cases, physicians should be alerted to the possibility of concurrent CM.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2014-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">359</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010AGUFM.T31A2124S"> <span id="translatedtitle">Gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> of the western Arctic ocean and its margins provide an imperfect window to a complex, multi-stage tectonic history (Invited)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Numerous scenarios are still in play for the tectonic development of the western Arctic. A wide range of kinematic models have been proposed for the opening of the Canadian basin. These models feature different combinations and geometries of extensional and transform motion and have informal descriptive names including the so-called ‘windshield wiper’, ‘railroad tracks’, ‘squeegee’, and ‘saloon door’ options. Another controversial issue is the timing and role of the gigantic Alpha-Mendeleev large igneous province relative to the tectonic stages. In our opinion, many current Arctic models have not adequately dealt with the mass and thermal fluxes implied by this huge province. Available data are extremely sparse for the circum-Arctic, although current political and economic interests are fueling accelerated data collection. Recent compilations of gravity and <span class="hlt">magnetic</span> data are currently the best bets for synoptic imaging, however imprecise, of crustal composition and structure. Modeling and interpretation of regional geophysical <span class="hlt">anomalies</span> provide some of the only available tests for scenario evaluation in the absence of more direct determinations of crustal structure and composition. Our goal in this talk is to review the key geophysical features of the western Arctic and relate these elements to the expectations of competing tectonic models. These key geophysical features include (1) contrasting Arctic domains of overall <span class="hlt">magnetic</span> “thickness” and <span class="hlt">anomaly</span> “fabric” (the domains correlate generally with broad tectonic categories); (2) cryptic sub-linear <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the Canada basin (interpreted by some authors to be oceanic stripes); (3) a subtle but persistent gravity trough in the central Canada basin (inferred by some authors to represent an extensional trough); (4) spectacular “shelf edge” free-air gravity <span class="hlt">anomalies</span> along the Canadian and Alaskan passive margins that show significant along-strike variation (which can be interpreted to reflect relative amount of magmatic activity); (5) complex and chaotic <span class="hlt">magnetic</span> texture and fabric in the Alpha-Mendeleev large igneous province (perhaps reflecting pre-intrusive structural features and trends); and (6) large-amplitude, long-wavelength “deep <span class="hlt">magnetic</span> highs” including well-studied examples in northern Alaska and north-western Canada (inferred to represent deep crustal elements that influence overall strength of the crust/upper mantle). The overall complexity of the Arctic geophysical <span class="hlt">anomaly</span> fabric is indicative of significant variation in crustal composition and reflects a complicated, multi-stage tectonic development. It seems very likely that the best tectonic solutions for the circum-Arctic will include sub-elements of many current end-member models.</p> <div class="credits"> <p class="dwt_author">Saltus, R. W.; Miller, E. L.; Gaina, C.</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">360</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2011AIPC.1399..607S"> <span id="translatedtitle">Zero Current <span class="hlt">Anomaly</span> In Non-Linear Transport Of High-Mobility InGaAs/InP 2DEG Structures In Quantizing <span class="hlt">Magnetic</span> Fields</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We report on the observation and study of quantum transport diamonds and Zero Current <span class="hlt">Anomaly</span> (ZCA) in the non-linear differential resistance rxx = dVxx/dI of high-mobility InxGa1-xAs/InP structures in quantizing <span class="hlt">magnetic</span> fields. The diamond-shaped features are observed in the grey-scale plots of rxx as a function of <span class="hlt">magnetic</span> field and dc current. Spin diamonds are revealed at higher <span class="hlt">magnetic</span> fields when spin levels at odd filling factors are well resolved. Unexpectedly, a narrow dip is observed in differential resistance vs. current at Idc = 0 in quantizing <span class="hlt">magnetic</span> fields, which we refer to as the ZCA effect.</p> <div class="credits"> <p class="dwt_author">Studenikin, S. A.; Granger, G.; Sachrajda, A. S.; Kam, A.; Poole, P. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-12-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_17");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">361</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AGUFM.T51A2557P"> <span id="translatedtitle">Crustal thickness and Vp/Vs estimates near the Brunswick <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> using receiver functions from the SESAME array</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The Southeastern Suture of the Appalachian Margin Experiment (SESAME) is designed to investigate lithospheric dynamics associated with the Paleozoic collision between the Suwanee terrane and Laurentia as well as subsequent Mesozoic rifting and passive margin formation. So far, we have deployed 63 broadband instruments along two N-S trending profiles across Georgia and northern Florida. A third NW-trending profile consisting of 19 stations extends across accreted terranes of the southern Appalachians from Augusta, GA to eastern TN. The N-S profiles are intended to provide constraints on variations in crustal structure across the Brunswick <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> (BMA), a prominent <span class="hlt">magnetic</span> low coinciding with south-dipping crustal-scale seismic reflectors evident on COCORP profiles in south Georgia. The seismic reflectivity is likely a consequence of suturing, but the BMA has been interpreted as an edge effect related to collision as well as an effect of mafic magmatism south of the suture zone. H-k stacking using 10 teleseismic receiver functions from station W27, located ~50-km north of the suture on the western N-S profile, suggests a crustal thickness (H) of 42-44 km and average crustal Vp/Vs (k) of 1.73-1.80. These estimates are in agreement with previous well-constrained stacking results from USNSN station GOGA, located ~70-km to the northeast, that suggest a crustal thickness of 41-43 km and average Vp/Vs 1.72-1.76. The proposed suture zone itself lies beneath sediments of the Atlantic Coastal Plain, and receiver functions from stations in this region appear to be strongly affected by high-amplitude reverberations within the sedimentary column. Therefore, preliminary H-k stacking results from stations directly over the BMA may be unreliable. However, receiver functions from station W23 near the Inner Piedmont-Coastal Plain boundary (near the north, up-dip end of the suture zone) display variations in Ps delay time and amplitude with event back-azimuth. Receiver functions from the S-azimuth (South American trench) display a relatively weak Ps conversion at ~4 seconds, while receiver functions from the NW-azimuth (Aleutian trench) show a more complex signal with an arrival at ~4 s followed by a higher-amplitude arrival at ~6 seconds. This may be indicative of compositional heterogeneity across the suture, anisotropy within the crust or mantle, or complexity at the crust-mantle interface related to collision of the Suwanee terrane. Forthcoming data from additional stations will provide improved constraints on crustal structure across the BMA.</p> <div class="credits"> <p class="dwt_author">Parker, E. H.; Hawman, R. B.; Fischer, K. M.; Wagner, L. S.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">362</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19820017716&hterms=CeCl&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCeCl"> <span id="translatedtitle">The reduction, verification and interpretation of MAGSAT <span class="hlt">magnetic</span> data over Canada</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">Correlations between the MAGSAT scalar <span class="hlt">anomaly</span> map produced at the Earth Physics ranch and other geophysical and geological data reveal relationships between high <span class="hlt">magnetic</span> field and some metamorphic grade shields, as well as between low <span class="hlt">magnetic</span> field and shield regions of lower metamorphic grade. An intriguing contrast exists between the broad low <span class="hlt">anomaly</span> field over the Nasen-Gakkel Ridge (a <span class="hlt">spreading</span> plate margin) and the high <span class="hlt">anomaly</span> field over Iceland (part of a <span class="hlt">spreading</span> margin). Both regions have high heat flow, and presumably thin <span class="hlt">magnetic</span> crust. This indicates that Iceland is quite anomalous in its <span class="hlt">magnetic</span> character, and possible similarities with the Alpha Ridge are suggested. Interesting correlations exist between MAGSAT <span class="hlt">anomalies</span> around the North Atlantic, after reconstructing the fit of continents into a prerifting configuration. These correlations suggest that several orogenies in that region have not completely destroyed an ancient <span class="hlt">magnetization</span> formed in high grade Precambrian rocks.</p> <div class="credits"> <p class="dwt_author">Coles, R. L. (principal investigator); Haines, G. V.; Vanbeek, G. J.; Walker, J. K.; Newitt, L. R.; Nandi, A.</p> <p class="dwt_publisher"></p> <p class="publishDate">1982-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">363</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014GCarp..65..163P"> <span id="translatedtitle">Joint interpretation of gravity and <span class="hlt">magnetic</span> data in the Kolárovo <span class="hlt">anomaly</span> region by separation of sources and the inversion method of local corrections</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a new interpretation of the Kolárovo gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> in the Danube Basin based on an inversion methodology that comprises the following numerical procedures: removal of regional trend, depth-wise separation of signal of sources, approximation of multiple sources by 3D line segments, non-linear inversion based on local corrections resulting in found sources specified as 3D star-convex homogenous bodies and/or 3D contrasting structural contact surfaces. This inversion methodology produces several admissible solutions from the viewpoint of potential field data. These solutions are then studied in terms of their feasibility taking into consideration all available tectono-geological information. By this inversion methodology we interpret here the Kolárovo gravity and <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> jointly. Our inversion generates several admissible solutions in terms of the shape, size and location of a basic intrusion into the upper crust, or the shape and depth of the upper/lower crust interface, or an intrusion into the crystalline crust above a rise of the mafic lower crust. Our intrusive bodies lie at depths between 5 and 12 km. Our lower crust elevation rises to 12 km with and 8 km without the accompanying intrusion into the upper crust, respectively. Our solutions are in reasonable agreement with various previous interpretations of the Kolárovo <span class="hlt">anomaly</span>, but yield a better and more realistic geometrical resolution for the source bodies. These admissible solutions are next discussed in the context of geological and tectonic considerations, mainly in relation to the fault systems.</p> <div class="credits"> <p class="dwt_author">Prutkin, Ilya; Vajda, Peter; Bielik, Miroslav; Bezák, Vladimír; Tenzer, Robert</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-04-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">364</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2004JAG....56..195M"> <span id="translatedtitle">Earth analog for Martian <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>: remanence properties of hemo-ilmenite norites in the Bjerkreim-Sokndal intrusion, Rogaland, Norway</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">To explain the very large remanent <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> on Mars, which no longer has a global <span class="hlt">magnetic</span> field, it is important to evaluate rocks on Earth with the necessary properties of high natural remanent <span class="hlt">magnetization</span> (NRM) and coercivity. Here, we describe a possible analog from the 230-km 2 930 Ma Bjerkreim-Sokndal layered intrusion (BKS) in Rogaland, Norway. In the layered series of the BKS, fractional crystallization of jotunitic magma was punctuated by influx and mixing of more primitive magmas, producing six megacyclic units, each typically with early plagioclase-rich norites, intermediate hemo-ilmenite-rich norites and late magnetite norites with subordinate near end-member ilmenite. Following each influx, the magma resumed normal crystallization and, following the last, near the base of Megacyclic Unit IV, crystallization continued until norites gave way to massive fayalite-magnetite mangerites and quartz mangerites in the upper part of the intrusion. The Megacycles are marked on a regional aeromagnetic map by remanent-controlled negative <span class="hlt">anomalies</span> over ilmenite norites and induced positive <span class="hlt">anomalies</span> over magnetite norites and mangerites. A prominent negative <span class="hlt">anomaly</span> (with amplitude -13,000 nT in a high-resolution helicopter survey, down to -27,000 nT below background in ground <span class="hlt">magnetic</span> profiles) occurs over the central part of Megacyclic Unit IV. The <span class="hlt">anomaly</span> is centered on ilmenite norite Unit IVe and is most intense where cumulate layering is near vertical at the southeast edge of the Bjerkreim Lobe of the intrusion at Heskestad. Here, Unit IVe is flanked to the east by magnetite norite of Unit IVc and country-rock gneisses (group E) and to the west by Unit IVf magnetite norite and mangerites (group W). <span class="hlt">Magnetic</span> properties were measured on 128 oriented samples. Susceptibilities are similar for all three sample groups at ˜8×10 -2, but Koenigsberger ratios are very different, with average values of 7.7 for IVe, and <1 for groups E and W. The IVe samples, with only a few percent of oxides, have the highest NRMs measured from the BKS, up to 74 A/m, with an average of 30.6 A/m, making them prime candidates for consideration as Mars analogs. The mean direction for IVe samples is D=17.6°, I=-79.9, a95=10°, almost opposite the present field. Evidence on origin of the strong NRM in IVe as compared to groups E and W, include greater abundance of hemo-ilmenite and of orthopyroxene with hemo-ilmenite exsolution, and the strong lattice-preferred orientation of both in a relationship favorable for "lamellar <span class="hlt">magnetism</span>". Massive magnetite-free hemo-ilmenite ores in anorthosite from the same district also produce negative <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>. They have a substantial but much lower NRM, suggesting that there are special oxide properties in the IVe rocks at Heskestad.</p> <div class="credits"> <p class="dwt_author">McEnroe, S. A.; Brown, L. L.; Robinson, Peter</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-10-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">365</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012APS..MARD32008M"> <span id="translatedtitle">Infrared phonon <span class="hlt">anomaly</span> and <span class="hlt">magnetic</span> excitations in single-crystal Cu3Bi(SeO3)2O2Cl</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Infrared reflection as a function of temperature has been measured on the anisotropic single-crystal Cu3Bi(SeO3)2O2Cl. The complex dielectric function and optical properties along all three crystal axes of the orthorhombic cell were obtained via Kramers-Kronig analysis and by fits to a Drude-Lorentz model. Below 110 K drastic <span class="hlt">anomalies</span> in the phonon spectrum (e.g., new modes and splitting of existing modes) are observed along all three crystal axes. Transmission in the terahertz region as a function of temperature has revealed <span class="hlt">magnetic</span> excitations originating below the ferromagnetic ordering temperature, Tc=24 K. The origin of the excitations in the <span class="hlt">magnetic</span> state will be discussed in terms of their polarization and externally-applied <span class="hlt">magnetic</span> field dependence.</p> <div class="credits"> <p class="dwt_author">Miller, Kevin H.; Martin, C.; Xi, X.; Berger, H.; Carr, G. L.; Tanner, D. B.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-02-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">366</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JGRB..118.3742Z"> <span id="translatedtitle">The shallow structure of K?lauea caldera from high-resolution Bouguer gravity and total <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> mapping: Insights into progressive magma reservoir growth</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">conducted total <span class="hlt">magnetic</span> field and Bouguer gravity measurements to investigate the shallow structure beneath the summit caldera of K?lauea Volcano, Hawai'i. Two significant and distinctive <span class="hlt">magnetic</span> <span class="hlt">anomalies</span> were identified within the caldera. One is interpreted to be associated with a long-lived prehistoric eruptive center, the Observatory vent, located ~1 km east of the Hawaiian Volcano Observatory. The second <span class="hlt">magnetic</span> <span class="hlt">anomaly</span> corresponds to a set of eruptive fissures that strike northeast from Halema'uma'u Crater, suggesting this is an important transport pathway for magma. The Bouguer gravity data were inverted to produce 3-D models of density contrasts in the upper 2 km beneath K?lauea. The models detect 3.0 km3 of material, denser than 2800 kg m-3, beneath the caldera that may represent an intrusive complex centered northeast of Halema'uma'u. Recent temporal gravity studies indicate continual addition of mass beneath the caldera during 1975-2008 centered west of Halema'uma'u and suggest this is due to filling of void space. The growth of a large intrusive complex, apparent cyclical caldera formation, and continual mass addition without inflation, however, can also be explained by extensional rifting caused by the continual southward movement of K?lauea's unstable south flank.</p> <div class="credits"> <p class="dwt_author">Zurek, Jeffrey; Williams-Jones, Glyn</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-07-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">367</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012espc.conf..150W"> <span id="translatedtitle">The solar wind interactions with lunar <span class="hlt">magnetic</span> <span class="hlt">anomalies</span>: A case study of the Chang'E-2 plasma data near the Serenitatis antipode</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present the first and preliminary results on the near-Moon plasma environment, based on the spectrogram data obtained with the Solar Wind Ion Detector (SWID) onboard Chang'E-2 from 4 lunar orbits on 10-11 Oct 2010. These orbits, at a constant altitude of ~100 km, approach gradually the Lunar <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (LMA) at the Serenitatis antipode. The data reveal tentatively a region with decrement in proton density and enhancement in temperature. The near coincidence of this region with the Serenitatis antipode probably suggests the presence of a mini-magnetosphere associated with the LMA, which effectively shields and heats the incident Solar Wind (SW) protons.</p> <div class="credits"> <p class="dwt_author">Wang, X.-Q.; Cui, J.; Wang, X.-D.; Liu, J.-J.; Zhang, H.-B.; Zuo, W.; Su, Y.; Wen, W.-B.; Rème, H.; Dandouras, I.; Aoustin, C.; Li, C.-L.; Ouyang, Z.-Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-09-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">368</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012AdSpR..50.1600W"> <span id="translatedtitle">The Solar Wind interactions with Lunar <span class="hlt">Magnetic</span> <span class="hlt">Anomalies</span>: A case study of the Chang'E-2 plasma data near the Serenitatis antipode</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">In this paper, we present the first and preliminary results on the near-Moon plasma environment, based on the spectrogram data obtained with the Solar Wind Ion Detector (SWID) onboard Chang'E-2 from four lunar orbits on 10-11 Oct 2010. These orbits, at a constant altitude of ˜100 km, approach gradually the Lunar <span class="hlt">Magnetic</span> <span class="hlt">Anomaly</span> (LMA) at the Serenitatis antipode. The data reveal tentatively a region with decrement in proton density and enhancement in temperature. The near coincidence of this region with the Serenitatis antipode probably suggests the presence of a minimagnetosphere associated with the LMA, which effectively shields and heats the incident Solar Wind (SW) protons.</p> <div class="credits"> <p class="dwt_author">Wang, X.-Q.; Cui, J.; Wang, X.-D.; Liu, J.-J.; Zhang, H.-B.; Zuo, W.; Su, Y.; Wen, W.-B.; Rème, H.; Dandouras, I.; Aoustin, C.; Wang, M.; Tan, X.; Shen, J.; Wang, F.; Fu, Q.; Li, C.-L.; Ouyang, Z.-Y.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">369</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/1996AdSpR..18..107B"> <span id="translatedtitle">Modeling studies of equatorial plasma fountain and equatorial <span class="hlt">anomaly</span></span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The importance of diffusion, electrodynamic drift, amd neutral wind on the generation and modulation of the equatorial plasma fountain of the Earth's ionosphere is studied using the Sheffield University Plasmasphere-Ionosp