Science.gov

Sample records for cave lava beds

  1. Selected caves and lava-tube systems in and near Lava Beds National Monument, California

    USGS Publications Warehouse

    Waters, Aaron Clement; Donnelly-Nolan, Julie M.; Rogers, Bruce W.

    1990-01-01

    Much of the north and south flanks of the Medicine Lake shield were built from molten lava transmitted through lava tubes. These tubes formed beneath the congealing surface of basalt flows in somewhat the same way that a brook may continue to flow beneath a cover of its own winter ice. As molten lava emerges from a vent and flows downslope, congealing lava from the top and sides of the central channel often forms a bridge over the lava stream. The sticking together of bits of lava spatter and fragile lava crusts strengthens the bridge in the manner that thin crusts of floating ice raft together to cover a brook during early stages of a winter freeze. Eruption of basalt lava, however, is a much more violent and spasmodic process than the steady gathering of water that feeds a brook. If liquid lava stops rising from its source deep within the earth, the still-molten lava moving beneath the crusted-over top of a lava flow will continue to drain downhill and may ultimately leave an open lavatube cave-often large enough for people to walk through. It is rare, however, to find such a simple scenario recorded intact among the hundreds of lava-tube caves in the monument. Even before the top and walls of a lava flow have time to cool during a pause in lava supply, a new and violent eruption of lava may refill the open tube, overflow its upper end, and spread a new lava flow beside or on top of the first flow. Even if the original tube is large enough to contain the renewed supply of lava, this tube must deliver the new lava beyond the end of its original flow and thus the lava field extends farther and farther downslope. If the gradient of flow flattens, the tube may subdivide into a number of smaller distributaries, which spread laterally over the more gently sloping ground. 

  2. Mineral resources of the Devil's Garden Lava Bed, Squaw Ridge Lava Bed, and Four Craters Lava Bed Wilderness Study Areas, Lake County, Oregon

    SciTech Connect

    Keith, W.J.; King, H.D.; Gettings, M.E. ); Johnson, F.L. )

    1988-01-01

    The Devel's Garden lava Bed, Squaw Ridge Lava Bed, and Four Craters Lava Bed Wilderness Study Areas include approximately 70,940 acres and are underlain entirely by Pleistocene or Holocene lava flows and associated sediments. There is no evidence of hydrothermal alteration in the study areas. No resources were identified in the study areas, but there is low potential for perlite resources in the southern part of the Devil's Garden Lava Bed and the northern half of the Squaw Ridge Lava Bed areas. All three study areas have low potential for geothermal resources and for oil and gas resources.

  3. White Sands, Carrizozo Lava Beds, NM

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A truly remarkable view of White Sands and the nearby Carrizozo Lava Beds in southeast NM (33.5N, 106.5W). White Sands, site of the WW II atomic bomb development and testing facility and later post war nuclear weapons testing that can still be seen in the cleared circular patterns on the ground.

  4. Lunar Pit Craters Presumed to be the Entrances of Lava Caves by Analogy to the Earth Lava Tube Pits

    NASA Astrophysics Data System (ADS)

    Hong, Ik-Seon; Yi, Yu; Kim, Eojin

    2014-06-01

    Lava caves could be useful as outposts for the human exploration of the Moon. Lava caves or lava tubes are formed when the external surface of the lava flows cools more quickly to make a hardened crust over subsurface lava flows. The lava flow eventually ceases and drains out of the tube, leaving an empty space. The frail part of the ceiling of lava tube could collapse to expose the entrance to the lava tubes which is called a pit crater. Several pit craters with the diameter of around 100 meters have been found by analyzing the data of SELENE and LRO lunar missions. It is hard to use these pit craters for outposts since these are too large in scale. In this study, small scale pit craters which are fit for outposts have been investigated using the NAC image data of LROC. Several topographic patterns which are believed to be lunar caves have been found and the similar pit craters of the Earth were compared and analyzed to identify caves. For this analysis, the image data of satellites and aerial photographs are collected and classified to construct a database. Several pit craters analogous to lunar pit craters were derived and a morphological pit crater model was generated using the 3D printer based on this database.

  5. Erosion by flowing lava: Geochemical evidence in the Cave Basalt, Mount St. Helens, Washington

    USGS Publications Warehouse

    Williams, D.A.; Kadel, S.D.; Greeley, R.; Lesher, C.M.; Clynne, M.A.

    2004-01-01

    We sampled basaltic lava flows and underlying dacitic tuff deposits in or near lava tubes of the Cave Basalt, Mount St. Helens, Washington to determine whether the Cave Basalt lavas contain geochemical evidence of substrate contamination by lava erosion. The samples were analyzed using a combination of wavelength-dispersive X-ray fluorescence spectrometry and inductively-coupled plasma mass spectrometry. The results indicate that the oldest, outer lava tube linings in direct contact with the dacitic substrate are contaminated, whereas the younger, inner lava tube linings are uncontaminated and apparently either more evolved or enriched in residual liquid. The most heavily contaminated lavas occur closer to the vent and in steeper parts of the tube system, and the amount of contamination decreases with increasing distance downstream. These results suggest that erosion by lava and contamination were limited to only the initially emplaced flows and that erosion was localized and enhanced by vigorous laminar flow over steeper slopes. After cooling, the initial Cave Basalt lava flows formed an insulating lining within the tubes that prevented further erosion by later flows. This interpretation is consistent with models of lava erosion that predict higher erosion rates closer to sources and over steeper slopes. A greater abundance of xenoliths and xenocrysts relative to xenomelts in hand samples indicates that mechanical erosion rather than thermal erosion was the dominant erosional process in the Cave Basalt, but further sampling and petrographic analyses must be performed to verify this hypothesis. ?? Springer-Verlag 2003.

  6. Near-IR Reflectance Spectra in a Lava Tube Cave from a Robotic Platform

    NASA Astrophysics Data System (ADS)

    Chanover, N. J.; Uckert, K.; Voelz, D. G.; Xiao, X.; Hull, R.; Boston, P. J.; Parness, A.; Abcouwer, N.; Willig, A.; Fuller, C.

    2015-10-01

    We present preliminary field measurements of biovermiculations and other mineral deposits made at a lava tube cave in El Malpais National Monument, NM, using a rock climbing robot equipped with a near-infrared point spectrometer.

  7. Comparison of Bacterial Diversity in Azorean and Hawai’ian Lava Cave Microbial Mats

    PubMed Central

    MARSHALL HATHAWAY, JENNIFER J.; GARCIA, MATTHEW G.; BALASCH, MONICA MOYA; SPILDE, MICHAEL N.; STONE, FRED D.; DAPKEVICIUS, MARIA DE LURDES N. E.; AMORIM, ISABEL R.; GABRIEL, ROSALINA; BORGES, PAULO A. V.; NORTHUP, DIANA E.

    2015-01-01

    Worldwide, lava caves host colorful microbial mats. However, little is known about the diversity of these microorganisms, or what role they may play in the subsurface ecosystem. White and yellow microbial mats were collected from four lava caves each on the Azorean island of Terceira and the Big Island of Hawai’i, to compare the bacterial diversity found in lava caves from two widely separated archipelagos in two different oceans at different latitudes. Scanning electron microscopy of mat samples showed striking similarities between Terceira and Hawai’ian microbial morphologies. 16S rRNA gene clone libraries were constructed to determine the diversity within these lava caves. Fifteen bacterial phyla were found across the samples, with more Actinobacteria clones in Hawai’ian communities and greater numbers of Acidobacteria clones in Terceira communities. Bacterial diversity in the subsurface was correlated with a set of factors. Geographical location was the major contributor to differences in community composition (at the OTU level), together with differences in the amounts of organic carbon, nitrogen and copper available in the lava rock that forms the cave. These results reveal, for the first time, the similarity among the extensive bacterial diversity found in lava caves in two geographically separate locations and contribute to the current debate on the nature of microbial biogeography. PMID:26924866

  8. Wintering bats of the upper Snake River Plain: occurrence in lava-tube caves

    SciTech Connect

    Genter, D.L.

    1986-04-30

    Distribution and habitat selection of hibernating bats at the Idaho National Engineering Laboratory (INEL) and adjacent area are reported. Exploration of over 30 lava-tube caves revealed that two species, Myotis leibii and Plecotus townsendii, hibernate in the upper Snake River Plain. Five species, M. lucifugus, M. evotis, Eptesicus fuscus, Lasionycteris noctivagans, and Lasiurus cinereus are considered migratory. Myotis leibii and P. townsendii hibernate throughout much of the area, occasionally in mixed-species groups. Myotis leibii uses the dark and protected regions of the cave, usually wedged into tiny pockets and crevices near or at the highest portion of the ceiling. Individuals of P. townsendii may be found at any height or depth in the cave. Temperature appears to be primary limiting factor in habitat selection. Myotis leibii was found in significantly cooler air temperatures than P. townsendii. Neither species tolerated continuous temperatures below 1.5 C. Relative humidity does not seem to be a significant factor in the distribution or habitat selection of the two species in lava-tube caves. 18 references, 1 figure, 1 table.

  9. Assessing the origin of unusual organic formations in lava caves from Canary Islands (Spain)

    NASA Astrophysics Data System (ADS)

    Miller, Ana Z.; de la Rosa, Jose M.; Garcia-Sanchez, Angela M.; Pereira, Manuel F. C.; Jurado, Valme; Fernández, Octavio; Knicker, Heike; Saiz-Jimenez, Cesareo

    2016-04-01

    Lava tubes, like other caves, contain a variety of speleothems formed in the initial stage of a lava tube formation or due to leaching and subsequent precipitation of secondary minerals. Primary and secondary mineral formations in lava caves are mainly composed of silicate minerals, although secondary minerals common in limestone caves have been also reported in this type of caves. In addition, unusual colored deposits have been found on the walls and ceilings of lava tubes, some of them of unknown origin and composition. A brown to black-colored mud-like deposits was observed in "Llano de los Caños" Cave, La Palma Island, Canary Islands, Spain. These black deposits coat the wall and ceiling of the lava tube where sub-horizontal fractures occur. FESEM-EDS, X-ray micro-computed tomography and mineralogical analyses were conducted for morphological, 3D microstructural and compositional characterization of these unusual speleothem samples. These techniques revealed that they are mainly composed of amorphous materials, suggesting an organic carbon composition. Hence, analytical pyrolysis (Py-GC/MS), solid-state 13C Nuclear Magnetic Resonance (NMR) and stable isotope analysis were applied to assess the nature and origin of the black deposits. The combination of these analytical tools permits the identification of specific biomarkers (di- and triterpenoids) for tracing the potential sources of the organic compounds in the speleothems. For comparison purposes, samples from the topsoil and overlaying vegetation were also analyzed. Chromatograms resulting from the Py-GC/MS showed an abundance of polysaccharides, lipids and terpenoids typically derived from the vegetation of the area (Erica arborea). In addition, levoglucosan, polycyclic aromatic hydrocarbons and N-containing heterocyclic compounds were detected. They probably derived from the leaching of charred vegetation resulting from a wildfire occurred in the area in 2012. The lack of the typical pattern of odd

  10. Evaluation of Lava Tube Formation Mechanisms Using Three-Dimensional Mapping, and Viscosity Modeling: Lava Beds National Monument, California.

    NASA Astrophysics Data System (ADS)

    Dedecker, J.; Gant, M.

    2014-12-01

    This study explores the relationships between lava tube morphology, lava effusion rate estimates, and the mechanism of lava tube formation. Effusion rate estimates for extinct lava tubes were calculated using a combination of three-dimensional mapping of lava tube caves, and viscosity models utilizing whole-rock compositions (Giordano et al., 2008, Earth Planet. Sci. Lett.), and petrographic data (Harris and Allen, 2008, J. Geophys. Res.). The mechanism of lava tube formation was evaluated using measured tube lengths and effusion rate estimates and comparing these data with observations from Hawaiian channel- and tube-fed flows (Pinkerton and Wilson, 1994, J. Volcanol. Geoth. Res.). Three-dimensional map data for lava tube caves were collected using a laser rangefinder to measure the cross-sectional shape and down-tube distance, and a tandem compass/inclinometer to measure the azimuth and inclination between survey stations in the tube. Total tube length consists of the mapped tube length plus the distance between collapse pits and trenches along the trend of the tube. Effusion rates were estimated using the Hagen-Poiseuille equation, measured mean cross-sectional radii and slope of lava tubes, and estimated effective viscosities of rock samples collected from mapped tubes at temperatures between 1080-1160 °C and water contents of 0-1 wt.%. A lava density of 1560 g/cm3was used for 0.40 vesicle fraction basalt. There is a positive correlation between measured tube lengths and cross-sectional radii (Fig. 1). We propose that this relationship reflects the positive correlation between flow lengths and effusion rates in active Hawaiian channel-fed flows. Measured tube lengths vs. effusion rate estimates were compared with data for Hawaiian channel-fed flows (Fig. 2). The two data sets overlap and have parallel trends. These results suggest that the lava tube caves studied formed by the roofing-over of channel-fed flows or had segments of channel-fed flow. We propose

  11. Diversity of Ammonia Oxidation (amoA) and Nitrogen Fixation (nifH) Genes in Lava Caves of Terceira, Azores, Portugal

    PubMed Central

    Hathaway, Jennifer J. Marshall; Sinsabaugh, Robert L.; Dapkevicius, Maria De Lurdes N. E.; Northup, Diana E.

    2015-01-01

    Lava caves are an understudied ecosystem in the subterranean world, particularly in regard to nitrogen cycling. The diversity of ammonia oxidation (amoA) and nitrogen fixation (nifH) genes in bacterial mats collected from lava cave walls on the island of Terceira (Azores, Portugal) was investigated using denaturing gradient gel electrophoresis (DGGE). A total of 55 samples were collected from 11 lava caves that were selected with regard to surface land use. Land use types above the lava caves were categorized into pasture, forested, and sea/urban, and used to determine if land use influenced the ammonia oxidizing and nitrogen fixing bacterial communities within the lava caves. The soil and water samples from each lava cave were analyzed for total organic carbon, inorganic carbon, total nitrogen, ammonium, nitrate, phosphate and sulfate, to determine if land use influences either the nutrient content entering the lava cave or the nitrogen cycling bacteria present within the cave. Nitrosospira-like sequences dominated the ammonia-oxidizing bacteria (AOB) community, and the majority of the diversity was found in lava caves under forested land. The nitrogen fixation community was dominated by Klebsiella pneumoniae-like sequences, and diversity was evenly distributed between pasture and forested land, but very little overlap in diversity was observed. The results suggest that land use is impacting both the AOB and the nitrogen fixing bacterial communities. PMID:26778867

  12. 76 FR 4721 - Minor Boundary Revision of Lava Beds National Monument

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-26

    ... to the protection of the ] significant historic and natural resources of the national monument. Dated... National Park Service Minor Boundary Revision of Lava Beds National Monument AGENCY: National Park Service....S.C. 460l- 9(c)(1), the boundary of the Petroglyph Point unit of Lava Beds National Monument...

  13. Lava Cave Microbial Communities Within Mats and Secondary Mineral Deposits: Implications for Life Detection on Other Planets

    PubMed Central

    Melim, L.A.; Spilde, M.N.; Hathaway, J.J.M.; Garcia, M.G.; Moya, M.; Stone, F.D.; Boston, P.J.; Dapkevicius, M.L.N.E.; Riquelme, C.

    2011-01-01

    Abstract Lava caves contain a wealth of yellow, white, pink, tan, and gold-colored microbial mats; but in addition to these clearly biological mats, there are many secondary mineral deposits that are nonbiological in appearance. Secondary mineral deposits examined include an amorphous copper-silicate deposit (Hawai‘i) that is blue-green in color and contains reticulated and fuzzy filament morphologies. In the Azores, lava tubes contain iron-oxide formations, a soft ooze-like coating, and pink hexagons on basaltic glass, while gold-colored deposits are found in lava caves in New Mexico and Hawai‘i. A combination of scanning electron microscopy (SEM) and molecular techniques was used to analyze these communities. Molecular analyses of the microbial mats and secondary mineral deposits revealed a community that contains 14 phyla of bacteria across three locations: the Azores, New Mexico, and Hawai‘i. Similarities exist between bacterial phyla found in microbial mats and secondary minerals, but marked differences also occur, such as the lack of Actinobacteria in two-thirds of the secondary mineral deposits. The discovery that such deposits contain abundant life can help guide our detection of life on extraterrestrial bodies. Key Words: Biosignatures—Astrobiology—Bacteria—Caves—Life detection—Microbial mats. Astrobiology 11, 601–618. PMID:21879833

  14. Lava cave microbial communities within mats and secondary mineral deposits: implications for life detection on other planets.

    PubMed

    Northup, D E; Melim, L A; Spilde, M N; Hathaway, J J M; Garcia, M G; Moya, M; Stone, F D; Boston, P J; Dapkevicius, M L N E; Riquelme, C

    2011-09-01

    Lava caves contain a wealth of yellow, white, pink, tan, and gold-colored microbial mats; but in addition to these clearly biological mats, there are many secondary mineral deposits that are nonbiological in appearance. Secondary mineral deposits examined include an amorphous copper-silicate deposit (Hawai'i) that is blue-green in color and contains reticulated and fuzzy filament morphologies. In the Azores, lava tubes contain iron-oxide formations, a soft ooze-like coating, and pink hexagons on basaltic glass, while gold-colored deposits are found in lava caves in New Mexico and Hawai'i. A combination of scanning electron microscopy (SEM) and molecular techniques was used to analyze these communities. Molecular analyses of the microbial mats and secondary mineral deposits revealed a community that contains 14 phyla of bacteria across three locations: the Azores, New Mexico, and Hawai'i. Similarities exist between bacterial phyla found in microbial mats and secondary minerals, but marked differences also occur, such as the lack of Actinobacteria in two-thirds of the secondary mineral deposits. The discovery that such deposits contain abundant life can help guide our detection of life on extraterrestrial bodies. PMID:21879833

  15. Cave microbial community composition in oceanic islands: disentangling the effect of different colored mats in diversity patterns of Azorean lava caves.

    PubMed

    Riquelme, Cristina; Rigal, François; Hathaway, Jennifer J M; Northup, Diana E; Spilde, Michael N; Borges, Paulo A V; Gabriel, Rosalina; Amorim, Isabel R; Dapkevicius, Maria de Lurdes N E

    2015-12-01

    Processes determining diversity and composition of bacterial communities in island volcanic caves are still poorly understood. Here, we characterized colored microbial mats in 14 volcanic caves from two oceanic islands of the Azores using 16S rRNA gene sequences. Factors determining community diversity (α) and composition (β) were explored, namely colored mats, caves and islands, as well as environmental and chemical characteristics of caves. Additive partitioning of diversity using OTU occurrence showed a greater influence of β-diversity between islands and caves that may relate to differences in rare OTUs (singletons and doubletons) across scales. In contrast, Shannon diversity partitioning revealed the importance of the lowest hierarchical level (α diversity, colored mat), suggesting a dominance of cosmopolitan OTUs (>1%) in most samples. Cosmopolitan OTUs included members involved in nitrogen cycling, supporting the importance of this process in Azorean caves. Environmental and chemical conditions in caves did not show any significant relationship to OTU diversity and composition. The absence of clear differences between mat colors and across scales may be explained by (1) the geological youth of the cave system (cave communities have not had enough time to diverge) or/and (2) community convergence, as the result of selection pressure in extreme environments. PMID:26564959

  16. Bald eagle winter roost characteristics in Lava Beds National Monument, California

    USGS Publications Warehouse

    Stohlgren, Thomas J.

    1993-01-01

    This study provided a survey of bald eagle (Haliaeetus leucocephalus) winter roost habitat (in 4 km2 of potential roost areas) in southern Lava Beds National Monument, California. A systematic-clustered sampling design (n=381 plots) was used to compare forest stand characteristics in two primary roost areas (Caldwell Butte and Eagle Nest Butte) and two potential roost areas (Hidden Valley and Island Butte). A 100 percent inventory of roost trees in Caldwell Butte (n=103 trees) and Eagle Nest Butte (n=44 trees) showed they were spatially clumped and restricted to 12.7 percent and 2.8 percent, respectively, of the study areas. Roost trees, primarily ponderosa pine (Pinus ponderosa), averaged 81.1 ± 1.3 cm dbh (mean ± 1 S.E.) compared to non-roost trees (>35 cm dbh) that averaged 52.2 ± 1.0 cm dbh. Roost trees were generally taller and more open-structured than non-roost trees. All four study sites had adequate numbers of mid-sized trees (10 to 50 cm dbh) to replace the current stock of older, larger roost trees. However, seedling and small trees (<10 cm dbh) in the roost areas were spatially clumped and few, suggesting that maintaining a continuous population of roost trees may be a problem in the distant future. Long-term studies of changing winter roost habitat and eagle use are essential to protect the bald eagle in the northwestern US.

  17. A geologic and hydrologic reconnaissance of Lava Beds National Monument and vicinity, California

    USGS Publications Warehouse

    Hotchkiss, W.R.

    1968-01-01

    Lava Beds National Monument is on the Modoc Plateau in Modoc and Siskiyou Counties. The principal geologic units in the vicinity are volcanic rocks, which in places are highly permeable and poorly permeable lake sedimentary deposits, all probably post-Oligocene in age. Yields and specific capacities of wells in the unconfined water body within volcanic rocks and lake deposits range widely, but in general are low in the lake deposits and higher in the volcanic rocks. A confined water body occurring in volcanic rocks underlying the lake deposits yields large quantities of water to three wells in the study area. Dissolved-solids content of ground water generally increases in proportion to the thickness of lake deposits penetrated and to proximity of the lake deposits. Water from wells drilled in the volcanic rocks several miles from the lake deposits and from wells penetrating the confined water body in volcanic rocks underlying the lake deposits contains small to moderate quantities of dissolved solids. Ground-water supplies can be developed almost anywhere in the study area by drilling wells to depths below the water table. In addition, there is a reasonable possibility of developing wells in a confined water body underlying the water-table system.

  18. Olivine-Respiring Bacteria Isolated from the Rock-Ice Interface in a Lava-Tube Cave, a Mars Analog Environment

    PubMed Central

    Smith, Amy R.; Popa, Rodica; Boone, Jane; Fisk, Martin

    2012-01-01

    Abstract The boundary between ice and basalt on Earth is an analogue for some near-surface environments of Mars. We investigated neutrophilic iron-oxidizing microorganisms from the basalt-ice interface in a lava tube from the Oregon Cascades with perennial ice. One of the isolates (Pseudomonas sp. HerB) can use ferrous iron Fe(II) from the igneous mineral olivine as an electron donor and O2 as an electron acceptor. The optimum growth temperature is ∼12–14°C, but growth also occurs at 5°C. Bicarbonate is a facultative source of carbon. Growth of Pseudomonas sp. HerB as a chemolithotrophic iron oxidizer with olivine as the source of energy is favored in low O2 conditions (e.g., 1.6% O2). Most likely, microbial oxidation of olivine near pH 7 requires low O2 to offset the abiotic oxidation of iron. The metabolic capabilities of this bacterium would allow it to live in near-surface, icy, volcanic environments of Mars in the present or recent geological past and make this type of physiology a prime candidate in the search for life on Mars. Key Words: Extremophiles—Mars—Olivine—Iron-oxidizing bacteria—Redox. Astrobiology 12, 9–18. PMID:22165996

  19. Lunar Lava Tubes as Potential Human Settlements and Refuge Sites

    NASA Astrophysics Data System (ADS)

    Lemke, K. A.; Mardon, A. A.

    2015-10-01

    Lava tubes have been detected on the surface of Earth's moon via satellite images. Upon further exploration of these caves through robotic technology and other means, a refuge place for astronauts may be installed.

  20. Geology of Caves.

    ERIC Educational Resources Information Center

    Davies, W. E.; Morgan, I. M.

    One of a series of general interest publications on science topics, the booklet provides those interested in the study of caves (speleology) with a nontechnical introduction to the subject. Separate sections examine types of caves, how caves form, cave features, minerals found in caves, uses of caves, and caves as natural underground laboratories.…

  1. Lava Lamp

    ERIC Educational Resources Information Center

    Leif, Todd R.

    2008-01-01

    This past semester I brought a Lava Lite[R] Lamp into my classroom. Why bring such a thing into class? Many of today's students are part of the "retro" movement. They buy clothes from the '60s, they wear their hair like people did in the '60s, and they look for the ideals and themes related to living in the 1960s. Physics education reform is also…

  2. Candidate cave entrances on Mars

    USGS Publications Warehouse

    Cushing, Glen E.

    2012-01-01

    This paper presents newly discovered candidate cave entrances into Martian near-surface lava tubes, volcano-tectonic fracture systems, and pit craters and describes their characteristics and exploration possibilities. These candidates are all collapse features that occur either intermittently along laterally continuous trench-like depressions or in the floors of sheer-walled atypical pit craters. As viewed from orbit, locations of most candidates are visibly consistent with known terrestrial features such as tube-fed lava flows, volcano-tectonic fractures, and pit craters, each of which forms by mechanisms that can produce caves. Although we cannot determine subsurface extents of the Martian features discussed here, some may continue unimpeded for many kilometers if terrestrial examples are indeed analogous. The features presented here were identified in images acquired by the Mars Odyssey's Thermal Emission Imaging System visible-wavelength camera, and by the Mars Reconnaissance Orbiter's Context Camera. Select candidates have since been targeted by the High-Resolution Imaging Science Experiment. Martian caves are promising potential sites for future human habitation and astrobiology investigations; understanding their characteristics is critical for long-term mission planning and for developing the necessary exploration technologies.

  3. Lava Flows

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Context image for PIA03658 Lava Flows

    These relatively young lava flows are part of Arsia Mons.

    Image information: VIS instrument. Latitude -22.5N, Longitude 242.3E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  4. CAVE WINDOW

    DOEpatents

    Levenson, M.

    1960-10-25

    A cave window is described. It is constructed of thick glass panes arranged so that interior panes have smaller windowpane areas and exterior panes have larger areas. Exterior panes on the radiation exposure side are remotely replaceable when darkened excessively. Metal shutters minimize exposure time to extend window life.

  5. Lava Lamp

    NASA Astrophysics Data System (ADS)

    Leif, Todd R.

    2008-04-01

    This past semester I brought a Lava Lite® Lamp into my classroom. Why bring such a thing into class? Many of today's students are part of the "retro" movement. They buy clothes from the '60s, they wear their hair like people did in the '60s, and they look for the ideals and themes related to living in the 1960s. Physics education reform is also examining ideas from the "retro" world of science. This was the post-Sputnik era, a time when science was done by actually doing it and not necessarily by lecturing about it. Cliff Swartz, former TPT editor, once mentioned during a presentation at a Texas AAPT meeting, "The world of physics teaching is cyclic, like a swinging pendulum. We as physics teachers jump from `new ideas' back to our old ones, each generation testing what works best for them."

  6. Caving in the Classroom

    ERIC Educational Resources Information Center

    Yoder, Holly

    2010-01-01

    During Cave Week, more than 200 students explore a simulated cave environment and participate in cave-related activities. Active cavers from a local club bring in equipment and photos and speak about their caving experiences. As student groups explore the simulated cave, other groups participate in different activities where they can create bat…

  7. Founder effects initiated rapid species radiation in Hawaiian cave planthoppers.

    PubMed

    Wessel, Andreas; Hoch, Hannelore; Asche, Manfred; von Rintelen, Thomas; Stelbrink, Björn; Heck, Volker; Stone, Fred D; Howarth, Francis G

    2013-06-01

    The Hawaiian Islands provide the venue of one of nature's grand experiments in evolution. Here, we present morphological, behavioral, genetic, and geologic data from a young subterranean insect lineage in lava tube caves on Hawai'i Island. The Oliarus polyphemus species complex has the potential to become a model for studying rapid speciation by stochastic events. All species in this lineage live in extremely similar environments but show strong differentiation in behavioral and morphometric characters, which are random with respect to cave age and geographic distribution. Our observation that phenotypic variability within populations decreases with increasing cave age challenges traditional views on founder effects. Furthermore, these cave populations are natural replicates that can be used to test the contradictory hypotheses. Moreover, Hawaiian cave planthoppers exhibit one of the highest speciation rates among animals and, thus, radically shift our perception on the evolutionary potential of obligate cavernicoles. PMID:23696661

  8. Founder effects initiated rapid species radiation in Hawaiian cave planthoppers

    PubMed Central

    Wessel, Andreas; Hoch, Hannelore; Asche, Manfred; von Rintelen, Thomas; Stelbrink, Björn; Heck, Volker; Stone, Fred D.; Howarth, Francis G.

    2013-01-01

    The Hawaiian Islands provide the venue of one of nature’s grand experiments in evolution. Here, we present morphological, behavioral, genetic, and geologic data from a young subterranean insect lineage in lava tube caves on Hawai‘i Island. The Oliarus polyphemus species complex has the potential to become a model for studying rapid speciation by stochastic events. All species in this lineage live in extremely similar environments but show strong differentiation in behavioral and morphometric characters, which are random with respect to cave age and geographic distribution. Our observation that phenotypic variability within populations decreases with increasing cave age challenges traditional views on founder effects. Furthermore, these cave populations are natural replicates that can be used to test the contradictory hypotheses. Moreover, Hawaiian cave planthoppers exhibit one of the highest speciation rates among animals and, thus, radically shift our perception on the evolutionary potential of obligate cavernicoles. PMID:23696661

  9. Lava Flows On Ascraeus Mons Volcano

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Ascraeus Mons Volcano: Like Earth, Mars has many volcanoes and volcanic features. This high-resolution view shows some of the lava flows near the summit of Ascraeus Mons, one of the three giant shield volcanoes known as the 'Tharsis Montes'. Volcanoes form when magma (molten rock) erupts out onto the surface of a planet. Based on Viking-era observations, Ascraeus Mons is considered to be one of the tallest volcanoes on Mars... its summit is more than 11 km (6.8 miles) above the surrounding plain. The summit is more than 23 km (14 miles) higher in elevation than the place where Mars Pathfinder landed in July 1997.

    Description of MOC Image: This picture shows an area that is about 20 km (12 miles) higher in elevation than the Mars Pathfinder landing site. The picture shows three main features: (1) a crater at the center-right, (2) a sinuous, discontinuous channel across the upper half, and (3) a rough and pitted, elevated surface across the lower half of the image.

    (1) Crater at center right. Distinguishing meteor craters from volcanic craters can sometimes be a challenge on Mars. This particular crater was most likely formed by meteor impact because it has a raised rim and a faint radial ejecta pattern around the outside of it. This crater is 600 m (2000 feet) across, about 3/4 the size of the famous 'Meteor Crater' near Winslow, Arizona.

    (2) Sinuous channel. The type of discontinuous channel running across the upper half of the image is sometimes referred to as a 'sinuous rille'. These are common on the volcanic plains of the Moon and among volcanoes and volcanic plains on Earth. Such a channel was once a lava tube. It is running down the middle of an old lava flow. The 'tube' looks like a 'channel' because its roof has collapsed. The discontinuous nature of this channel is the result of the collapse, or 'cave-in' of what was once the roof of the lava tube. It is common for certain types of relatively fluid lavas to form

  10. The Science of Exploring Caves.

    ERIC Educational Resources Information Center

    Reid, Frank S.

    1991-01-01

    An introduction to the science of speleology is presented. Discussed is why people explore caves--for the physical challenge, the thrill of discovery, and the joy of viewing their beauty. Cave conservation, cave biology, caving safety, and caving equipment are topics of discussion. A reading list on caves is included. (KR)

  11. BELLE STARR CAVE WILDERNESS STUDY AREA, ARKANSAS.

    USGS Publications Warehouse

    Haley, Boyd R.; Stroud, Raymond B.

    1984-01-01

    A mineral survey of the Belle Starr Cave Wilderness Study Area in Arkansas concluded that there is little promise for the occurrence of metallic mineral resources in the area. There is a probable resource potential for small quantities of natural gas. A coal bed that underlies the area contains demonstrated coal resources of about 22. 5 million tons in a bed that averages less than 28 in. thick. Despite its contained coal, this area is not shown as having a coal resource potential.

  12. Lava Flows On Ascraeus Mons Volcano

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Ascraeus Mons Volcano: Like Earth, Mars has many volcanoes and volcanic features. This high-resolution view shows some of the lava flows near the summit of Ascraeus Mons, one of the three giant shield volcanoes known as the 'Tharsis Montes'. Volcanoes form when magma (molten rock) erupts out onto the surface of a planet. Based on Viking-era observations, Ascraeus Mons is considered to be one of the tallest volcanoes on Mars... its summit is more than 11 km (6.8 miles) above the surrounding plain. The summit is more than 23 km (14 miles) higher in elevation than the place where Mars Pathfinder landed in July 1997.

    Description of MOC Image: This picture shows an area that is about 20 km (12 miles) higher in elevation than the Mars Pathfinder landing site. The picture shows three main features: (1) a crater at the center-right, (2) a sinuous, discontinuous channel across the upper half, and (3) a rough and pitted, elevated surface across the lower half of the image.

    (1) Crater at center right. Distinguishing meteor craters from volcanic craters can sometimes be a challenge on Mars. This particular crater was most likely formed by meteor impact because it has a raised rim and a faint radial ejecta pattern around the outside of it. This crater is 600 m (2000 feet) across, about 3/4 the size of the famous 'Meteor Crater' near Winslow, Arizona.

    (2) Sinuous channel. The type of discontinuous channel running across the upper half of the image is sometimes referred to as a 'sinuous rille'. These are common on the volcanic plains of the Moon and among volcanoes and volcanic plains on Earth. Such a channel was once a lava tube. It is running down the middle of an old lava flow. The 'tube' looks like a 'channel' because its roof has collapsed. The discontinuous nature of this channel is the result of the collapse, or 'cave-in' of what was once the roof of the lava tube. It is common for certain types of relatively fluid lavas to form

  13. Lunar Lava Tube Sensing

    NASA Technical Reports Server (NTRS)

    York, Cheryl Lynn; Walden, Bryce; Billings, Thomas L.; Reeder, P. Douglas

    1992-01-01

    Large (greater than 300 m diameter) lava tube caverns appear to exist on the Moon and could provide substantial safety and cost benefits for lunar bases. Over 40 m of basalt and regolith constitute the lava tube roof and would protect both construction and operations. Constant temperatures of -20 C reduce thermal stress on structures and machines. Base designs need not incorporate heavy shielding, so lightweight materials can be used and construction can be expedited. Identification and characterization of lava tube caverns can be incorporated into current precursor lunar mission plans. Some searches can even be done from Earth. Specific recommendations for lunar lava tube search and exploration are (1) an Earth-based radar interferometer, (2) an Earth-penetrating radar (EPR) orbiter, (3) kinetic penetrators for lunar lava tube confirmation, (4) a 'Moon Bat' hovering rocket vehicle, and (5) the use of other proposed landers and orbiters to help find lunar lava tubes.

  14. Come to our Cave.

    ERIC Educational Resources Information Center

    Cassidy, Joan

    2001-01-01

    Describes an activity for first-grade students in which they learn about cave paintings and become spelunkers, or people who explore caves as a hobby, making their own paper head-lanterns. Explains that students draw animals on the walls of their "cave" (a dark hallway lined with brown kraft paper). (CMK)

  15. Upper Pleistocene interstratal piping-cave speleogenesis: The Seso Cave System (Central Pyrenees, Northern Spain)

    NASA Astrophysics Data System (ADS)

    Bartolomé, M.; Sancho, C.; Moreno, A.; Oliva-Urcia, B.; Belmonte, Á.; Bastida, J.; Cheng, H.; Edwards, R. L.

    2015-01-01

    The Seso Cave System (SCS, South Central Pyrenees, Northeastern Spain) develops in poorly soluble marly interstratum between limestone beds of Eocene age. We propose an innovative and singular pseudokarstic speleogenetic model under vadose conditions based on cave morphological evidence, physicochemical and mineralogical characteristics of the Eocene marly host rock, U-Th dating of cave deposits, and local geological and geomorphological information. Eocene marls are shown to be sensitive to dispersion processes supported by their high clay content and the high concentration of sodium and low electrical conductivity in the seepage water. Runoff inside the cave results from water that infiltrates through joints and seepage water in cave walls. Thereby piping processes become very active, triggering mechanical scouring and outwashing mechanisms. The hydraulic gradient required to develop piping activity is determined by regional fluvial incision. The base level controlling water discharge during opening of the SCS coincides with a terrace of the Ara River dated at 65 ka BP. Considering this age, as well as the U-Th age of the oldest speleothems dated in the cave at 38 ka BP, the timing of the SCS interstratal piping-cave speleogenesis is constrained to the Upper Pleistocene; very likely at the end of Marine Isotope Stage 4 during a period characterized by high water availability following glacial retreat in northern Iberian mountains.

  16. Olympus Mons Lava Flows

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 05 April 2002) Olympus Mons stands 26 km above the surrounding plains, which is three times taller than Mt. Everest, and is the tallest volcano in the solar system. Olympus Mons is also wider (585 km) than the state of Arizona. Although these are impressive dimensions an astronaut would find walking these slopes easy, as they are typically only 2 to 5 degrees. This image contains numerous lava flows, leveed lava channels, a discontinuous sinuous rille (thought to be a collapsed lava tube) and lava plains. Close examination of the sinuous rille reveals that portions of the roof of the lava tube have not completely collapsed. All of these features can be seen in basaltic (iron and magnesium rich black rock) volcanic regions on Earth like Hawaii and Iceland. Impact craters are scarce, indicating a relatively young age (several hundred million years old) for these surfaces.

  17. Geology of caves

    USGS Publications Warehouse

    Morgan, I.M., Davies,W.E.

    1991-01-01

    A cave is a natural opening in the ground extending beyond the zone of light and large enough to permit the entry of man. Occurring in a wide variety of rock types and caused by widely differing geological processes, caves range in size from single small rooms to intercorinecting passages many miles long. The scientific study of caves is called speleology (from the Greek words spelaion for cave and logos for study). It is a composite science based on geology, hydrology, biology, and archaeology, and thus holds special interest for earth scientists of the U.S. Geological Survey.

  18. Lava flows and domes

    SciTech Connect

    Fink, J. )

    1989-01-01

    This book discusses emplacement of silicic domes and mafic lava flows. The authors have utilized the combination of field, experimental and theoretical methods to constrain various characteristics of recently-emplaced lavas, including dimensions, growth rates, surface morphology, deformation styles, rheology, and volatile contents. Filed measurements from numerous volcanoes are presented. Focus is on data from Mount St. Helens. The value of such investigations is addressed.

  19. Lava Flow Dynamics

    NASA Technical Reports Server (NTRS)

    Taylor, G. Jeffrey

    1996-01-01

    This grant originally had four major tasks, all of which were addressed to varying extents during the course of the research: (1) Measure the fractal dimensions of lava flows as a function of topography, substrate, and rheology; (2) The nature of lava tube systems and their relation to flow fields; (3) A quantitative assessment of lava flow dynamics in light of the fractal nature of lava flow margins; and (4) Development and application of a new remote sensing tool based on fractal properties. During the course of the research, the project expanded to include the following projects: (1) A comparison of what we can-learn from remote sensing studies of lava flow morphology and from studies of samples of lava flows; (2) Study of a terrestrial analog of the nakhlites, one of the groups of meteorites from Mars; and (3) Study of the textures of Hawaiian basalts as an aid in understanding the dynamics (flow rates, inflation rates, thermal history) of flow interiors. In addition, during the first year an educational task (development and writing of a teacher's guide and activity set to accompany the lunar sample disk when it is sent to schools) was included.

  20. Empowering Women through Caving.

    ERIC Educational Resources Information Center

    Gabert, Julie

    1997-01-01

    Describes an introductory horizontal caving experience for college-age women who were uncomfortable with their bodies, insecure with movement, and unwilling to take big risks. The darkness and quiet of the cave released inhibitions and promoted group cohesion, feelings of intimacy and safety, self-discovery, and self-confidence. (SV)

  1. Cave Water Studies.

    ERIC Educational Resources Information Center

    O'Keefe, Elizabeth S.

    1996-01-01

    Describes a comparative study project where seventh grade students tested water samples from 10 cave sites that had been tested 24 years ago in a study that had attempted to determine if pollution in the environment had reached cave water. Discusses lab skills and some results of the study. (JRH)

  2. Basaltic Lava Channels

    NASA Astrophysics Data System (ADS)

    Cashman, K. V.; Griffiths, R. W.; Kerr, R. C.

    2004-12-01

    In Hawaii, the mode of lava transport - through open channels or through insulating lava tubes - determines the thermal, rheological, and emplacement history of a lava flow. Most Hawaiian lavas are erupted at near-liquidus temperatures and are therefore crystal-poor; lava transport through open channels allows rapid cooling and consequent rapid increases in lava crystallinity. Solidified aa flows resulting from channelized flow are typically fine-grained throughout their thickness, indicating cooling of the entire flow thickness during transport. In contrast, transport of lava through insulating tubes permits flow over long distances with little cooling. Flows emerging from such tubes typically have pahoehoe flow surfaces with glassy crusts. Groundmass textures that coarsen from the flow rind to the interior reflect rates of post-emplacement, rather than syn-emplacement, cooling. To distinguish eruption conditions that result in lava channels from those that allow formation of lava tubes, we have performed a series of laboratory experiments involving injection of PEG 600 (a wax with a Newtonian rheology and freezing temperature of 19ºC) into cold water through both uniform and non-uniform sloping channels. In uniform channels, tube formation can be distinguished from open channel flow using a dimensionless parameter based on a solidification time scale, an advection time scale, and a Rayleigh number that describes convection by heat loss from crust-free shear zones. Theoretical analysis predicts that in the open channel regime, the width of the crust (dc) will vary with the channel width (W) as dc = W5/3. Crustal coverage of non-uniform channels in both laboratory experiments and field examples from Kilauea Volcano, Hawaii, is consistent with this prediction. However, experiments in non-uniform channels illustrate additional controls on the surface coverage of lava channels. Most important is crustal extension resulting from flow acceleration through constrictions

  3. New Species of Campodeidae (Diplura) from Mexican caves.

    PubMed

    Sendra, Alberto; Palacios, Jose; Garcia, Arturo; Montejo, Maira

    2016-01-01

    Six new taxa of Campodeidae (Diplura) are described in the genera Litocampa, Juxtlacampa, Oncinocampa, and Tachycampa. We also redescribe the interesting species Juxtlacampa juxtlahucensis Wygodzinsky, 1944 from Juxtlahuaca cave in Guerrero, Mexico. All of these taxa are cave-dwelling species with more or less noticeable troglobiomorphic features They inhabit the subterranean ecosystem in six limestone massifs and one lava tube cave in the central states of Mexico. Four of these species are included in the "tachycampoide" group and one species in the "podocampoide" group (sensu Bareth & Conde). Nine species already known in Central and South America of the "tachycampoide" group, in such poorly-sampled regions compared with the eight species in the well-sampled Mediterranean region (Ibero-Sardinia and north Africa), suggest an American origin for this group. PMID:27395944

  4. Carroll Cave: a Missouri legend

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Carroll Cave is one of the premiere caves of Missouri and the Ozarks region. At over 20 miles of surveyed passage, it is the 2nd longest cave in the state and 33rd longest in the nation. It is also the largest known cave formed in the Ordovician aged (443-485 million years ago) Gasconade Dolomite o...

  5. The foaming of lavas

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.; Walton, W.

    1976-01-01

    Foaming is of great practical and theoretical significance for volcanic processes on the earth, the moon, and perhaps the meteorite parent bodies. The theory of foams agrees with steelmaking experience to indicate that their presence depends on the existence of solutes in the lavas which reduce the surface tension, and are not saturated. These solutes concentrate at the surface, and are called surfactants. The surfactant responsible for the formation of volcanic ash was not identified; it appears to be related to the oxygen partial pressure above the lava. This fact may explain why lunar and meteoritic melts are not observed to foam. Experimental studies are needed to clarify the process.

  6. A multi-method approach for speleogenetic research on alpine karst caves. Torca La Texa shaft, Picos de Europa (Spain)

    NASA Astrophysics Data System (ADS)

    Ballesteros, Daniel; Jiménez-Sánchez, Montserrat; Giralt, Santiago; García-Sansegundo, Joaquín; Meléndez-Asensio, Mónica

    2015-10-01

    Speleogenetic research on alpine caves has advanced significantly during the last decades. These investigations require techniques from different geoscience disciplines that must be adapted to the methodological constraints of working in deep caves. The Picos de Europa mountains are one of the most important alpine karsts, including 14% of the World's Deepest Caves (caves with more than 1 km depth). A speleogenetic research is currently being developed in selected caves in these mountains; one of them, named Torca La Texa shaft, is the main goal of this article. For this purpose, we have proposed both an optimized multi-method approach for speleogenetic research in alpine caves, and a speleogenetic model of the Torca La Texa shaft. The methodology includes: cave surveying, dye-tracing, cave geometry analyses, cave geomorphological mapping, Uranium series dating (234U/230Th) and geomorphological, structural and stratigraphical studies of the cave surroundings. The SpeleoDisc method was employed to establish the structural control of the cavity. Torca La Texa (2653 m length, 215 m depth) is an alpine cave formed by two cave levels, vadose canyons and shafts, soutirage conduits, and gravity-modified passages. The cave was formed prior to the Middle Pleistocene and its development was controlled by the drop of the base level, producing the development of the two cave levels. Coevally to the cave levels formation, soutirage conduits originated connecting phreatic and epiphreatic conduits and vadose canyons and shafts were formed. Most of the shafts were created before the local glacial maximum (43-45 ka) and only two cave passages are related to dolines developed in recent times. The cave development is strongly related to the structure, locating the cave in the core of a gentle fold with the conduits' geometry and orientation controlled by the bedding and five families of joints.

  7. Gas discharges in fumarolic ice caves of Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Fischer, T. P.; Curtis, A. G.; Kyle, P. R.; Sano, Y.

    2013-12-01

    Fumarolic ice caves and towers on Erebus are the surface expression of flank degassing on the world's southernmost active volcano. The caves are formed by warm gases and steam escaping from small vents on the lava flow floors that melts the overlying ice and snow. Extremophiles in the caves may be analogues for extraterrestrial environments. Over the past four Austral summers, mapping, gas and thermal monitoring conducted under the Erebus Caves Project has provided insights into the ice cave formation processes and the relationships between cave structures, magmatic processes, and weather. Gas samples were collected during the 2012 - 2013 field season in 4 ice caves (Warren, Harry's Dream, Sauna, Haggis Hole) as well as the thermal ground at Tramway Ridge. The vents at all of these sites are characterized by diffuse degassing through loose lava or cracks in the lava flow floor. Vent temperatures ranged from 5 to 17°C in most caves and at Tramway Ridge. In Sauna cave the temperature was 40°C. Gases were sampled by inserting a perforated 1 m long, 5 mm diameter stainless steel tube, into the vents or hot ground. Giggenbach bottles, copper tubes and lead glass bottles were connected in series. The gases were pumped at a slow rate (about 20 ml per minute) using a battery pump for 12-24 hours to flush the system. After flushing samples were collected for later analyses. All samples are dominated by atmospheric components, however, carbon dioxide (0.1 to 1.9%), methane (0.005 to 0.01%), hydrogen (0.002 to 0.07%), and helium (0.0009 to 0.002 %) are above air background. Nitrogen (average 74%) and oxygen (23.5%) are slightly below and above air values, respectively. Helium isotopes show minor input of mantle derived helium-3 with 3He4He ratios ranging from 1.03 to 1.18 RA (where RA is the ratio of air). This represents the first detection of hydrogen and helium in the caves. Methane could be produced by anaerobic respiration of subsurface microbes or hydrothermal

  8. LAVA Applications to Open Rotors

    NASA Technical Reports Server (NTRS)

    Kiris, Cetin C.; Housman, Jeff; Barad, Mike; Brehm, Christoph

    2015-01-01

    Outline: LAVA (Launch Ascent Vehicle Aerodynamics); Introduction; Acoustics Related Applications; LAVA Applications to Open Rotor; Structured Overset Grids; Cartesian Grid with Immersed Boundary; High Speed Case; High Speed Case with Plate Low Speed Case.

  9. Cave speleothems as repositories of microbial biosignatures

    NASA Astrophysics Data System (ADS)

    Miller, Ana Z.; Jurado, Valme; Pereira, Manuel F. C.; Fernández, Octavio; Calaforra, José M.; Dionísio, Amélia; Saiz-Jimenez, Cesareo

    2015-04-01

    The need to better understand the biodiversity, origins of life on Earth and on other planets, and the wide applications of the microbe-mineral interactions have led to a rapid expansion of interest in subsurface environments. Recently reported results indicated signs of an early wet Mars and rather recent volcanic activity which suggest that Mars's subsurface can house organic molecules or traces of microbial life, making the search for microbial life on Earth's subsurface even more compelling. Caves on Earth are windows into the subsurface that harbor a wide variety of mineral-utilizing microorganisms, which may contribute to the formation of biominerals and unusual microstructures recognized as biosignatures. These environments contain a wide variety of redox interfaces and stable physicochemical conditions, which enhance secondary mineral precipitation and microbial growth under limited organic nutrient inputs. Enigmatic microorganisms and unusual mineral features have been found associated with secondary mineral deposits or speleothems in limestone caves and lava tubes. In this study, Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray spectroscopy (EDS) analyses were conducted on cave speleothem samples to assess microbe-mineral interactions, evaluate biogenicity, as well as to describe unusual mineral formations and microbial features. Microbial mats, extracellular polymeric substances, tubular empty sheaths, mineralized cells, filamentous fabrics, as well as "cell-sized" etch pits or microborings produced by bacterial cells were observed on minerals. These features evidence microbe-mineral interactions and may represent mineralogical signatures of life. We can thus consider that caves on Earth are plausible repositories of terrestrial biosignatures where we can look for microbial signatures. Acknowledgments: AZM acknowledges the support from the Marie Curie Intra-European Fellowship within the 7th European Community Framework

  10. Flow direction determination of lava flows.

    NASA Technical Reports Server (NTRS)

    Smith, E. I.; Rhodes, R. C.

    1972-01-01

    The flow direction technique, previously applied to ash-flow sheets, can be used to determine direction of movement and locate eruptive centers for lava flows. The method provides statistically stronger and more consistent flow direction data for lava than ash-flow tuff. The accuracy and reliability of the technique was established on the porphyritic basaltic andesite of Mount Taylor, New Mexico, which erupted from a known center, the Mount Taylor Amphitheater. The technique was then applied to volcanic units with unknown sources: the John Kerr Peak Quartz Latite and mid-Tertiary andesite flows in the Mogollon Mountains, both in southwestern New Mexico. The flow direction technique indicated flow patterns and suggested source areas for each rock unit. In the Mogollon Mountains flow direction measurements were supported by independent directional criteria such as dips of cross beds, stratigraphic thickening, facies changes, and megascopic textures.-

  11. Estimation of general and set steps of roof caving in rock mass with excavations at mining. Numerical modelling.

    NASA Astrophysics Data System (ADS)

    Eremin, M.; Makarov, P.

    2016-04-01

    The results of 2D modelling of rock mass elements fracture are shown in the article. The results of modelling are in a good agreement with empirical and theoretical estimations of roof caving steps for the flat-dipping coal seams when the horizons are not so deep (less than 600 m). The estimations of the general and set steps of roof caving are given for the lava conditions at different lengths of the main roof containing sandstone.

  12. High-Resolution Imaging of Lava Flow Terrains on Mars by MRO HiRISE

    NASA Astrophysics Data System (ADS)

    Crumpler, L. S.; Keszthelyi, L. P.; Jaeger, W. L.; McEwen, A. S.; HiRISE Team

    2007-12-01

    Lava flows account for a significant fraction of the surface of Mars and HiRISE has imaged a diverse selection of these areas at resolutions comparable to "air photos" on Earth. Although some lava are extensively impact "gardened" or mantled, many areas retain primary geomorphologic information at meter-scale. Primary characteristics similar to that of late Cenozoic lava flows in arid areas of Earth are visible in the HiRISE images of even some Hesperian lava plains. The extensive mantling by wind-blown deposits in some of the more youthful volcanic terrains (e.g., Tharsis) may, like terrestrial counterparts, be a result of the excessively rough surface trapping mobilized sand. Evidence for lava flow inflation, including lava-rise plateaus and pits and deformation both vertically and laterally of lava crusts, is documented in areas of flood lavas. Other lava flows are clearly fed from surface channels resulting in dispersive flow surface pattern. Lava flows with hummocky surface textures are comparable to terrestrial flows with auto-brecciated and disturbed surfaces, but the Martian flows are often much larger than typical terrestrial examples. Kilometer-scale areas of puzzle-work plates characterize some flood lava flows. The abundance of plate-like and rubbly deformation styles observed at many localities on Mars is consistent with examples of rubbly pahoehoe seen in situ by the Spirit rover. Rubbly pahoehoe may be a common primary surface texture for many areas of plains-like lava flow emplacement such as the Hesperian lava plains. Sinuous rill-like channels headed at distinct vents and collapse pits suggest significant lava erosion and correspondingly high effusion rates. While the Athabasca Valles channel bed forms appear to be associated with major aqueous outflows, the entire region is draped with lava.

  13. Bubble-Induced Cave Collapse

    PubMed Central

    Girihagama, Lakshika; Nof, Doron; Hancock, Cathrine

    2015-01-01

    Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned “natural” instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers bubbles rising to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar bubble dynamics, fluid dynamics of bubble-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a “collapse”. We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the bubbles were produced using a syringe located at the cave floor. PMID:25849088

  14. Bubble-induced cave collapse.

    PubMed

    Girihagama, Lakshika; Nof, Doron; Hancock, Cathrine

    2015-01-01

    Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned "natural" instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers bubbles rising to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar bubble dynamics, fluid dynamics of bubble-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a "collapse". We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the bubbles were produced using a syringe located at the cave floor. PMID:25849088

  15. Lava tubes and aquifer vulnerability in the upper Actopan River basin, Veracruz, México

    NASA Astrophysics Data System (ADS)

    Espinasa-Pereña, R.; Delgado Granados, H.

    2011-12-01

    Rapid infiltration leads to very dry conditions on the surface of some volcanic terrains, with large allogenic streams sometimes sinking underground upon reaching a lava flow. Aquifers in lava flows tend to be heterogeneous and discontinuous, generally unconfined and fissured, and have high transmissivity. Springs associated with basalts may be very large but are typically restricted to lava-flow margins. Concern has been expressed regarding the potential for lava-tube caves to facilitate groundwater contamination similar to that afflicting some karst aquifers (Kempe et al., 2003; Kiernan et al., 2002; Halliday 2003). The upper Actopan River basin is a series of narrow valleys excavated in Tertiary volcanic brechias. Several extensive Holocene basaltic tube-fed lava flows have partially filled these valleys. The youngest and longest flow originates at El Volcancillo, a 780 ybP monogenetic volcano. It is over 50 km long, and was fed through a major master tube, the remains of which form several lava-tube caves (Gassos and Espinasa-Pereña, 2008). Another tube-fed flow initiates at a vent at the bottom of Barranca Huichila and can be followed for 7 km to where it is covered by the Volcancillo flow. The Huichila River is captured by this system of lava tubes and can be followed through several underground sections. In dry weather the stream disappears at a sump in one of these caves, although during hurricanes it overflows the tube, floods the Tengonapa plain, and finally sinks through a series of skylights into the master tube of the Volcancillo flow. Near villages, the cave entrances are used as trash dumps, which are mobilized during floods. These include household garbage, organic materials associated with agriculture and even medical supplies. This is a relatively recent phenomenon, caused by population growth and the building of houses above the lava flows. The water resurges at El Descabezadero, gushing from fractures in the lava above the underlying brechias

  16. Winter distribution and use of high elevation caves as foraging sites by the endangered Hawaiian hoary bat, Lasiurus cinereus semotus

    USGS Publications Warehouse

    Bonaccorso, Frank; Montoya-Aiona, Kristina; Pinzari, Corinna A.; Todd, Christopher M.

    2016-01-01

    We examine altitudinal movements involving unusual use of caves by Hawaiian hoary bats, Lasiurus cinereus semotus, during winter and spring in the Mauna Loa Forest Reserve (MLFR), Hawai‘i Island. Acoustic detection of hoary bat vocalizations, were recorded with regularity outside 13 lava tube cave entrances situated between 2,200 to 3,600 m asl from November 2012 to April 2013. Vocalizations were most numerous in November and December with the number of call events and echolocation pulses decreasing through the following months. Bat activity was positively correlated with air temperature and negatively correlated with wind speed. Visual searches found no evidence of hibernacula nor do Hawaiian hoary bats appear to shelter by day in these caves. Nevertheless, bats fly deep into caves as evidenced by numerous carcasses found in cave interiors. The occurrence of feeding buzzes around cave entrances and visual observations of bats flying in acrobatic fashion in cave interiors point to the use of these spaces as foraging sites. Peridroma moth species (Noctuidae), the only abundant nocturnal, flying insect sheltering in large numbers in rock rubble and on cave walls in the MLFR, apparently serve as the principal prey attracting hoary bats during winter to lava tube caves in the upper MLFR. Caves above 3,000 m on Mauna Loa harbor temperatures suitable for Pseudogymnoascus destructansfungi, the causative agent of White-nose Syndrome that is highly lethal to some species of North American cave-dwelling bats. We discuss the potential for White-nose Syndrome to establish and affect Hawaiian hoary bats.

  17. Olympus Mons Lava Flows

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-437, 30 July 2003

    Olympus Mons is the largest volcano on Mars. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some of the lava flows on the middle south flank of the giant volcano. Illuminated from the lower right, this picture is located near 16.4oN, 135.5oW.

  18. Lava Lakes on Io?

    NASA Astrophysics Data System (ADS)

    Lopes, R. M. C.; Kamp, L. W.; Smythe, W. D.; Howell, R.; Mouginis-Mark, P.; Kargel, J. S.; Radebaugh, J.; Turtle, E. P.; Perry, J.; Williams, D. A.; Carlson, R. W.; Doute, S.; Galileo NIMS Team

    2003-05-01

    At least 152 active volcanic centers have been identified on Jupiter's moon Io [Lopes et al., 2003, submitted to Icarus]. Eruptions at these centers include lava flows (``Promethean" type eruptions), explosive ``Pillanian" eruptions [Keszthelyi et al., 2001, JGR 106, 33,025-52] and volcanism confined within patera walls (``Lokian", Lopes et al., 2003). Understanding the Lokian eruption mechanism is particularly important because paterae are the most ubiquitous volcanic constructs on Io's surface [Radebaugh et al. 2001, JGR, 106, 33,005-33,020] and patera volcanism is the most common eruption type on Io. We use observations from Galileo's Near-Infrared Mapping Spectrometer (NIMS) and compare them with images from Galileo's Solid State Imaging system (SSI) to map the distribution of thermal emission at several Ionian paterae. This allows us to examine how thermal emission correlates with visible features, and to investigate how thermal emission varies with time. Galileo's close fly-bys of Io from 1999 to 2001 allowed NIMS to observe the volcanoes at relatively high spatial resolution (1-30 km pixel). At these scales, observations of the several paterae reveal that the greatest thermal emission occurs at the edges. This can be explained as the crust of a lava lake breaking up against the base of the patera (caldera) walls, similar to what has been observed at lava lakes on Earth. Comparison with terrestrial analogs shows that several Ionian active paterae, such as Loki, Tupan, and Emakong, have thermal properties consistent with relatively inactive lava lakes on Earth. We discuss these results and their implications for eruption styles and resurfacing on Io. This work was supported in part by NASA's Planetary Geology and Geophysics Program.

  19. Lava flows are fractals

    NASA Technical Reports Server (NTRS)

    Bruno, B. C.; Taylor, G. J.; Rowland, S. K.; Lucey, P. G.; Self, S.

    1992-01-01

    Results are presented of a preliminary investigation of the fractal nature of the plan-view shapes of lava flows in Hawaii (based on field measurements and aerial photographs), as well as in Idaho and the Galapagos Islands (using aerial photographs only). The shapes of the lava flow margins are found to be fractals: lava flow shape is scale-invariant. This observation suggests that nonlinear forces are operating in them because nonlinear systems frequently produce fractals. A'a and pahoehoe flows can be distinguished by their fractal dimensions (D). The majority of the a'a flows measured have D between 1.05 and 1.09, whereas the pahoehoe flows generally have higher D (1.14-1.23). The analysis is extended to other planetary bodies by measuring flows from orbital images of Venus, Mars, and the moon. All are fractal and have D consistent with the range of terrestrial a'a and have D consistent with the range of terrestrial a'a and pahoehoe values.

  20. Sandstone caves on Venezuelan tepuis: Return to pseudokarst?

    NASA Astrophysics Data System (ADS)

    Aubrecht, R.; Lánczos, T.; Gregor, M.; Schlögl, J.; Šmída, B.; Liščák, P.; Brewer-Carías, Ch.; Vlček, L.

    2011-09-01

    Venezuelan table mountains (tepuis) host the largest arenite caves in the world. The most frequently used explanation of their origin so far was the "arenization" theory, involving dissolution of quartz cement around the sand grains and subsequent removing of the released grains by water. New research in the two largest arenite cave systems - Churi-Tepui System in Chimanta Massif and Ojos de Cristal System in Roraima Tepui showed that quartz dissolution plays only a minor role in their speleogenesis. Arenites forming the tepuis are not only quartzites but they display a wide range of lithification and breakdown, including also loose sands and sandstones. Speleogenetic processes are mostly concentrated on the beds of unlithified sands which escaped from diagenesis by being sealed by the surrounding perfectly lithified quartzites. Only the so-called "finger-flow" pillars testify to confined diagenetic fluids which flowed in narrow channels, leaving the surrounding arenite uncemented. Another factor which influenced the cave-forming processes by about 30% was lateritization. It affects beds formed of arkosic sandstones and greywackes which show strong dissolution of micas, feldspars and clay minerals, turning then to laterite ("Barro Rojo"). The main prerequisite to rank caves among karst phenomena is dissolution. As the dissolution of silicate minerals other than quartz appears to play not only a volumetrically important role but even a trigger role, these arenitic caves may be ranked as karst.

  1. The Hypothesis of Caves on Mars Revisited Through MGS Data; Their Potential as Targets for the Surveyor Program

    NASA Technical Reports Server (NTRS)

    Grin, E. A.; Cabrol, N. A.; McKay, C. P.

    1999-01-01

    In a previous publication, we proposed the formation of caves at mega and microscale on Mars and emphasized their potential for the exobiology exploration. The recent MOC images have shown promising indicators that caves are actually existing on Mars. In the first section, we develop the theoretical potential formation of martian caves. Then, we show how MOC is supporting this hypothesis of their formation and the new types of environments it suggests. The existence of caves on Mars from microscale to microscale structures can be predicted according to the Mars geological and climatic history. A first global approach is to consider caves as a result of underground water activity combined with tectonic movement. They can be formed by: (1) diversion of channel courses in underground conduits; (2) fractures of surface drainage patterns; chaotic terrain and collapsed areas in general; (4) seepage face in valley walls and/or headwaters; (5) inactive hydrothermal vents and lava tubes.

  2. Petrogenesis of basalt-trachyte lavas from Olmoti Crater, Tanzania

    NASA Astrophysics Data System (ADS)

    Mollel, Godwin F.; Swisher, Carl C., III; McHenry, Lindsay J.; Feigenson, Mark D.; Carr, Michael J.

    2009-08-01

    .01 Ma. The age of Olmoti activity overlaps with ages reported for Ngorongoro Caldera, implying contemporaneous activity of multiple NVH volcanic centers during part of the eruption interval. Olmoti is considered the source for the bulk of interbedded volcanics and volcaniclastic deposits that comprise much of the upper Bed I section of nearby Olduvai Gorge, and part of the Laetoli sequence, both known for their well preserved fossils and archaeological remains. Age and chemical data reported here are compatible with those derived from tephra and lava interbedded in Bed I at Olduvai Gorge and from the Olpiro Beds at Laetoli.

  3. Magnetostratigraphy of Cave Sediments

    NASA Astrophysics Data System (ADS)

    Bosák, P.; Pruner, P.

    2007-05-01

    Karst and cave fills (karst sediments) are relatively special kinds of geologic materials, as the karst environment favors both the preservation of paleontological remains and their destruction: on one hand, karst is well known for its wealth of paleontological sites, on the other hand, most of cave fills are completely sterile (especially the inner-cave facies). Another specific feature is that karst systems can be "frozen" (halted) and then rejuvenated, often for several times. Reactivation processes may degrade the record into an unreadable form, often mixing karst fill of different ages (collapses, reworking, redepositions). Only the last accumulation phase has been dated in caves in most cases. The fossilisation of the cave (fill by deposits) and rejuvenation (exhumation of the fill) reflect changes in resurgence area. The rejuvenation of the karst process can excavate the previous cave fill completely, which is the most common case resulting from the polycyclicity and dynamics of cave environments. Under favorable settings, fills belonging to more infill phases and separated by distinct hiatuses (unconformities) can occur in one sedimentary profile. Such amalgamation is typical especially in ponor part of the cave. During our previous research we found, that owing to the specific character of karst sediments, the use of paleomagnetic methods can bring surprising result, without regards to the character of the method (correlated- ages not providing direct numerical output). The method can serve as helpful tool to interpret not only the age of cave sediments but also to understand the evolution of karst landscape and tectonic history of the region. To obtain more precise results, it is necessary to combine paleomagnetism with other methods of numerical-, relative- or correlated-dating. The analytical results confirmed that the complete step/field procedure offered by the alternating field and thermal demagnetization methods must be applied. The sampling for

  4. Olympus Mons Lava Flows

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-525, 26 October 2003

    This May 2003 Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) picture shows lava flows on the lower northern flanks of the large martian volcano, Olympus Mons. Located near 21.9oN, 132.9oW, the image features flows that moved down the north slope, toward the north/northeast (top/upper right). Sunlight illuminates this scene from the left/lower left; the picture covers an area about 3 km (1.9 mi) across.

  5. A new millipede, Austrotyla awishoshola n. sp., (Diplopoda, Chordeumatida, Conotylidae) from New Mexico, USA, and the importance of cave moss gardens as refugial habitats.

    PubMed

    Wynne, J Judson; Shear, William A

    2016-01-01

    Austrotyla awishoshola n. sp. is described from the moss gardens of one lava tube cave in El Malpais National Monument, Cibola Co., New Mexico. Most chordeumatidans require mesic conditions, and these environments are limited to moss gardens in several cave entrances and beneath cave skylights in El Malpais. Presently, this species is known from the moss gardens of a single of cave in the monument. We suggest A. awishoshola may be a climatic relict, having become restricted to the cave environment following the end of the Pleistocene. We discuss the importance of cave moss gardens as refugial and relictual habitats. Recommendations are provided to aid in the conservation and management of A. awishoshola and these habitats. PMID:27394265

  6. Egyptian Sea Cave

    ERIC Educational Resources Information Center

    Journal of College Science Teaching, 2005

    2005-01-01

    This brief article describes an archaeological expedition to the Red Sea coast area of Egypt in 2004. Kathryn Bard, an associate professor of archaeology at Boston University, along with her team, discovered the well-preserved cedar timbers of an ancient Egyptian seafaring vessel near the entrance to a large man-made cave. Limestone tablets with…

  7. Arsia Mons Lava Flows

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    This VIS image of lava flows to the west of Arsia Mons looks very similar to the lava flows south of Arsia Mons. It is very likely that the flows were occurring at the same time(s) in both areas.

    Image information: VIS instrument. Latitude -2.9, Longitude 228.5 East (131.5 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  8. Glacioclimatological study of Perennial Ice in the Fuji Ice Cave, Japan. Part I. Seasonal variation and mechanism of maintenance

    SciTech Connect

    Ohata, Tetsuo; Furukawa, Teruo; Higuchi, Keiji )

    1994-08-01

    Perennial cave ice in a cave located at Mt. Fuji in central Japan was studied to investigate the basic characteristics and the cause for existence of such ice under warm ground-level climate considering the ice cave as a thermal and hydrological system. Fuji Ice Cave is a lava tube cave 150 m in length with a collapsed part at the entrance. Measurements from 1984 to 1986 showed that the surface-level change of floor ice occurred due to freezing and melting at the surface and that melting at the bottom of the ice was negligible. The annual amplitude of change in surface level was larger near the entrance. Meterological data showed that the cold air inflow to the cave was strong in winter, but in summer the cave was maintained near 0[degrees]C with only weak inflow of warm air. The predominant wind system was from the entrance to the interior in both winter and summer, but the spatial scale of the wind system was different. Heat budget consideration of the cave showed that the largest component was the strong inflow of subzero dry air mass in winter. Cooling in winter was compensated for by summer inflow of warm air, heat transport from the surrounding ground layer, and loss of sensible heat due to cooling of the cave for the observed year. Strong inflow of cold air and weak inflow of warm air, which is extremely low compared to the ground level air, seemed to be the most important condition. Thus the thermal condition of the cave is quasi-balanced at the presence condition below 0[degrees]C with ice. It can be said that the interrelated result of the climatological and special structural conditions makes this cave very cold, and allows perennial ice to exist in the cave. Other climatological factors such as precipitation seem to be minor factors. 17 refs., 3 figs., 3 tabs.

  9. Arsia Mons Lava Flows

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    The lava flows from Arsia Mons are some of the youngest flows in the region. The region of flows south of the volcano have had little modification and appear very similar in appearance to Hawaiian lava flows. This VIS image shows typical flows for the region. The flows are long, fairly narrow, overlapping, and with various surface features and textures.

    Image information: VIS instrument. Latitude -19.5, Longitude 240.1 East (119.9 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  10. Eroding Lava Flows

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Today's image illustrates how radically the wind can affect the surface of Mars. The lava flows in this region have been covered by fine materials, and eroded by the sand blasting action of the wind. In this region the winds are blowing to the west, eroding the lava surface to form small east/west ridges and bumps. Given enough time the winds will change the appearance of the surface to such a large extent that all flow features will be erased.

    Image information: VIS instrument. Latitude -11.7, Longitude 220 East (140 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  11. The microbiology of Lascaux Cave.

    PubMed

    Bastian, F; Jurado, V; Nováková, A; Alabouvette, C; Saiz-Jimenez, C

    2010-03-01

    Lascaux Cave (Montignac, France) contains paintings from the Upper Paleolithic period. Shortly after its discovery in 1940, the cave was seriously disturbed by major destructive interventions. In 1963, the cave was closed due to algal growth on the walls. In 2001, the ceiling, walls and sediments were colonized by the fungus Fusarium solani. Later, black stains, probably of fungal origin, appeared on the walls. Biocide treatments, including quaternary ammonium derivatives, were extensively applied for a few years, and have been in use again since January 2008. The microbial communities in Lascaux Cave were shown to be composed of human-pathogenic bacteria and entomopathogenic fungi, the former as a result of the biocide selection. The data show that fungi play an important role in the cave, and arthropods contribute to the dispersion of conidia. A careful study on the fungal ecology is needed in order to complete the cave food web and to control the black stains threatening the Paleolithic paintings. PMID:20056706

  12. Degassing driving crystallization of plagioclase phenocrysts in lava tube stalactites on Mount Etna (Sicily, Italy)

    NASA Astrophysics Data System (ADS)

    Lanzafame, Gabriele; Ferlito, Carmelo

    2014-10-01

    Basaltic lava flows can form tubes in response to the cooling of the outer surface. We collected lava stalactites (frozen lava tears) and sampled lava from the ceilings of three lava tubes on Mount Etna. Comparison of the petrographic characters between ceiling lavas and relative stalactites reveals surprising differences in the groundmass textures and crystal compositions. Major and trace element contents in stalactites show only a slight increase in alkali and SiO2 compared to ceiling lava, whereas significant differences exist in composition and textures between plagioclases within the ceiling lava and those within the stalactites, being in the last case definitively more An-rich. We advance the hypothesis that the high temperature reached in the cave caused the exsolution of the volatiles still trapped in the dripping melt. The volatiles, mainly H2O, formed bubbles and escaped from the melt; such a water-loss might have promoted the silicate polymerization in the stalactites resulting in the growth of An-rich plagioclase phenocrysts. Our results have important implications: in fact plagioclase phenocrysts are usually associated with intratelluric growth and are often considered as the main petrologic evidence for the existence of a magma chamber. The textural and chemical features of plagioclases in stalactites prove that phenocryst growth in syn to post-eruptive conditions is plausible and clearly explains the relatively low viscosity of many phenocryst-rich lava flows on Mount Etna, as well as on many other volcanoes around the world. Therefore, we can conclude that plagioclase phenocrysts cannot exclusively be considered as having originated within a magma chamber.

  13. Lava Lakes in Io's Paterae

    NASA Astrophysics Data System (ADS)

    Radebaugh, J.; McEwen, A. S.; Milazzo, M.; Davies, A. G.; Keszthelyi, L. P.; Geissler, P.

    2002-05-01

    New Galileo images and Galileo and Cassini temperature data lend credence to previous proposals that some of the paterae on Io contain lava lakes, similar in some ways to those observed on Earth. Galileo's October 2001 I32 flyby produced spectacular new high resolution observations of Io's paterae, their margins, and floors. Images reveal where lavas have filled Emakong Patera and overtopped its margins. Landslides from the peaks of Tohil Mons are not present on the adjacent floor of a dark patera, perhaps because they have slumped into a molten lava pit. Dark lavas have filled and drained back from colorful Tupan Patera, leaving a ring of material on its walls. This patera also shows evidence of interaction between molten sulfur and silicate lavas, a relationship observed at the terrestrial Poas Volcano (Francis et al., 1980, Nature 283, 754-756; Oppenheimer and Stevenson, 1990, La Recherche 21,1088-1090). The extremely uniformly dark materials in many other paterae could also be lava lakes. Pele Volcano on Io, in particular, has previously been considered a lava lake based on several characteristics (Davies et al., 2001, JGR 106,33,079-33,103). Recent analyses of eclipse images of Pele from Cassini reveal average temperatures of 1375 K, with variations on short (~10 minute) timescales, consistent with active fountaining in a lava lake. Similar oscillations around high temperatures over these time scales are seen in terrestrial lava lakes, such as at Kupaianaha (Flynn et al., GRL, 19,6461-6476, 1993) and Erta Ale (Bessard, Caillet and others, in progress). Nightside high resolution (60 m/pixel) images from Galileo I32 reveal a region of overturning and convection, with some areas reaching in excess of 1800 K, verifying very high-temperature components identified in high-resolution NIMS data (Lopes et al., 2001, JGR, 106, 33,053-33,078). This region is ringed with small hotspots, comparable to locations of breakup and fountaining at the margins of many terrestrial

  14. Deriving Lava Eruption Temperatures on Io Using Lava Tube Skylights

    NASA Astrophysics Data System (ADS)

    Davies, A. G.; Keszthelyi, L. P.; McEwen, A. S.

    2015-12-01

    The eruption temperature of Io's silicate lavas constrains Io's interior state and composition [1] but reliably measuring this temperature remotely is a challenge that has not yet been met. Previously, we established that eruption processes that expose large areas at the highest temperatures, such as roiling lava lakes or lava fountains, are suitable targets for this task [2]. In this study we investigate the thermal emission from lava tube skylights for basaltic and ultramafic composition lavas. Tube-fed lava flows are known on Io so skylights could be common. Unlike the surfaces of lava flows, lava lakes, and lava fountains which all cool very rapidly, skylights have steady thermal emission on a scale of days to months. The thermal emission from such a target, measured at multiple visible and NIR wavelengths, can provide a highly accurate diagnostic of eruption temperature. However, the small size of skylights means that close flybys of Io are necessary, requiring a dedicated Io mission [3]. We have modelled the thermal emission spectrum for different skylight sizes, lava flow stream velocities, end-member lava compositions, and skylight radiation shape factors, determining the flow surface cooling rates. We calculate the resulting thermal emission spectrum as a function of viewing angle. From the resulting 0.7:0.9 μm ratios, we see a clear distinction between basaltic and ultramafic compositions for skylights smaller than 20 m across, even if sub-pixel. If the skylight is not resolved, observations distributed over weeks that show a stationary and steady hot spot allow the presence of a skylight to be confidently inferred. This inference allows subsequent refining of observation design to improve viewing geometry of the target. Our analysis will be further refined as accurate high-temperature short-wavelength emissivity values become available [4]. This work was performed at the Jet Propulsion Laboratory-California Institute of Technology, under contract to

  15. Lava flows and volcanic landforms

    NASA Astrophysics Data System (ADS)

    Tarquini, Simone

    2016-04-01

    Lava flows constitute a large portion of the edifice of basaltic volcanoes. The substantial difference existing between the emplacement dynamics of different basaltic lava flows suggests a relation between the dominant flow dynamic and the overall shape of the ensuing volcano. Starting from the seminal works of Walker (1971, 1973) it is proposed that the rate of heat dissipation per unit volume of lava can be the founding principium at the roots of the emplacement dynamics of lava flows. Within the general framework of the thermodynamics of irreversible processes, a conceptual model is presented, in which the dynamic of lava flows can evolve in a linear or in a nonlinear regime on the basis of the constraint active on the system: a low constraint promotes a linear dynamic (i.e. fluctuations are damped), a high constraint a nonlinear one (i.e. fluctuations are enhanced). Two cases are considered as end-members for a linear and a nonlinear dynamic in lava flows: the typical "Hawaiian" sheet flow and the classic "Etnean" channelized flow (respectively). In lava flows, the active constraint is directly proportional to the slope of the topography and to the thermal conductivity and thermal capacity of the surrounding environment, and is inversely proportional to the lava viscosity and to the supply rate. The constraint indicates the distance from the equilibrium conditions of the system, and determines the rate of heat dissipation per unit volume. In subaerial flows, the heat dissipated during the emplacement is well approximated by the heat lost through radiation, which can be retrieved through remote-sensing techniques and can be used to correlate dynamic and dissipation. The model presented recombines previously unrelated concepts regarding the dynamics and the thermal regimes observed in different lava flows, providing a global consistent picture. References Walker GPL (1971) Compound and simple lava flows and flood basalts. Bull Volcanol 35:579-590 Walker GPL (1973

  16. Caves: A Course of Study.

    ERIC Educational Resources Information Center

    Phillips, Jan

    Middle school students from The College School, a private school in Webster Groves (Missouri) have completed a class called "Caves and Crystallography." A thematic approach was used in the course in which students and teachers read books telling how caves were formed, saw movies which explained the delicate balance of life underground, made…

  17. Important caves to be identified

    NASA Astrophysics Data System (ADS)

    Criteria to identify significant caves on federal land are being developed by the Interior Department's Bureau of Land Management and the Agriculture Department's Forest Service under requirements of the Federal Cave Resources Protection Act of 1988. The departments gave advance notice of proposed rulemaking March 3 and invited suggestions and comments from the public for 30 days.The law requires protection, to the extent practical, of significant caves on lands administered by the Secretaries of Agriculture and Interior and includes authority to issue and revoke permits for collection and removal of cave resources and special provisions for regulation of cave resources on Indian lands. Final regulations must be published by August 18, 1989.

  18. The Unicorn Cave, Southern Harz Mountains, Germany: From known passages to unknown extensions with the help of geophysical surveys

    NASA Astrophysics Data System (ADS)

    Kaufmann, Georg; Nielbock, Ralf; Romanov, Douchko

    2015-12-01

    In soluble rocks (limestone, dolomite, anhydrite, gypsum, …), fissures and bedding partings can be enlarged with time by both physical and chemical dissolution of the host rock. With time, larger cavities evolve, and a network of cave passages can evolve. If the enlarged cave voids are not too deep under the surface, geophysical measurements can be used to detect, identify and trace these karst structures, e.g.: (i) gravity revealing air- and sediment-filled cave voids through negative Bouguer anomalies, (ii) electrical resistivity imaging (ERI) mapping different infillings of cavities either as high resistivities from air-filled voids or dry soft sediments, or low resistivities from saturated sediments, and (iii) groundwater flow through electrical potential differences (SP) arising from dislocated ionic charges from the walls of the underground flow paths. We have used gravity, ERI, and SP methods both in and above the Unicorn Cave located in the southern Harz Mountains in Germany. The Unicorn Cave is a show cave developed in the Werra dolomite formation of the Permian Zechstein sequence, characterised by large trunk passages interrupted by larger rooms. The overburden of the cave is only around 15 m, and passages are filled with sediments reaching infill thicknesses up to 40 m. We present results from our geophysical surveys above the known cave and its northern and southern extension, and from the cave interior. We identify the cave geometry and its infill from gravity and ERI measurements, predict previously unknown parts of the cave, and subsequently confirm the existence of these new passages through drilling. From the wealth of geophysical data acquired we derive a three-dimensional structural model of the Unicorn Cave and its surrounding, especially the cave infill.

  19. Wind, Water, and Lava

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 18 June 2003

    The three main geological agents acting on the Martian surface are visible in this image, within an outflow channel to the east of the Tharsis volcanos and north of Valles Marineris. In a wide channel previously eroded by water, linear features have been eroded into the rock by the wind. Later, lava flows embayed the streamlined rocks. A second, younger flow lobe is visible at the bottom of the image.

    Image information: VIS instrument. Latitude 17, Longitude 283.6 East (76.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  20. Survey and hydrogeology of Carroll Cave

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Carroll Cave, located in Camden County, Missouri, is the largest known cave formed in the Gasconade Dolomite of the Salem Plateau. Despite extensive visitation over the last 50 years and multiple survey efforts, a comprehensive map of the cave has never been produced. In 2002, the Carroll Cave Conse...

  1. Permeability of compacting porous lavas

    NASA Astrophysics Data System (ADS)

    Ashwell, P. A.; Kendrick, J. E.; Lavallée, Y.; Kennedy, B. M.; Hess, K.-U.; Aulock, F. W.; Wadsworth, F. B.; Vasseur, J.; Dingwell, D. B.

    2015-03-01

    The highly transient nature of outgassing commonly observed at volcanoes is in part controlled by the permeability of lava domes and shallow conduits. Lava domes generally consist of a porous outer carapace surrounding a denser lava core with internal shear zones of variable porosity. Here we examine densification using uniaxial compression experiments on variably crystalline and porous rhyolitic dome lavas from the Taupo Volcanic Zone. Experiments were conducted at 900°C and an applied stress of 3 MPa to 60% strain, while monitoring acoustic emissions to track cracking. The evolution of the porous network was assessed via X-ray computed tomography, He-pycnometry, and relative gas permeability. High starting connected porosities led to low apparent viscosities and high strain rates, initially accompanied by abundant acoustic emissions. As compaction ensued, the lavas evolved; apparent viscosity increased and strain rate decreased due to strain hardening of the suspensions. Permeability fluctuations resulted from the interplay between viscous flow and brittle failure. Where phenocrysts were abundant, cracks had limited spatial extent, and pore closure decreased axial and radial permeability proportionally, maintaining the initial anisotropy. In crystal-poor lavas, axial cracks had a more profound effect, and permeability anisotropy switched to favor axial flow. Irrespective of porosity, both crystalline samples compacted to a threshold minimum porosity of 17-19%, whereas the crystal-poor sample did not achieve its compaction limit. This indicates that unconfined loading of porous dome lavas does not necessarily form an impermeable plug and may be hindered, in part by the presence of crystals.

  2. The Lava Morphology Database (LAMDA)

    NASA Astrophysics Data System (ADS)

    Peckyno, R. S.; de Silva, S. L.; Lopes, R. M.; Pieri, D. C.

    2009-12-01

    Many previous investigations of lava morphology have explored the relationship between flow properties (e.g., length, area, thickness) or flow features (e.g. lobation, flow ridging, aspect ratio), and process variables such as lava viscosity, yield strength, temperature, effusion rate, and local slope. Previous studies, however, have focused on individual attributes and features across a limited dataset of lava flows and have often noted the lack of a larger baseline dataset for comparison. Today, ready availability of high spatial and spectral resolution data for Earth’s volcanoes, coupled with computing advances, enable substantially enhanced network interaction between satellite analysis and field investigators around the world. We therefore propose a community effort, the Lava Morphology Database (LAMDA), to develop a comprehensive database for the morphology of terrestrial lava flows of varying composition, using GIS to integrate, georeference, and compare multiple datasets as well as automating many of the basic calculations. In a preliminary effort, we have measured and compiled lava flow features and attributes at 38 volcanoes including flow distance, surface area, aspect ratio, margin lobation, radii of curvature, height, and arc-length, corresponding cleft angle, flow surface ridging wavelength, lobe and landscape level slope, etc. As an example of the utility of this prototype database we present the initial results of an analysis of these data in light of existing viscosity and effusion rate based morphological models. Data resolution, computing power, and the number of field samples that can be practically analyzed have often necessitated that researchers assume that local slopes, viscosities, chemistries, and temperatures are constant across a flow. In contrast, LAMBDA will enable the exploration of factors that impact the emplacement of terrestrial lava flows at a much higher resolution than previous studies, as well as provide an extensive

  3. Radon and thoron in cave dwellings (Yan'an, China)

    SciTech Connect

    Wiegand, J.; Feige, S.; Xie Quingling; Schreiber, U.; Wieditz, K.; Wittmann, C.; Luo Xiarong

    2000-04-01

    {sup 222}Rn and {sup 220}Rn concentrations were measured in cave dwellings and brick houses in the region of Yan'an (China) during summer 1997. The underground dwellings are built into Quaternary loess, and all investigated houses are founded on it. The median values of indoor {sup 222}Rn and {sup 220}Rn concentrations are 42 (n = 18) and 77Bq m{sup {minus}3} (n = 15) for brick houses and 92 (n = 23) and 215 (n = 17) Bq m{sup {minus}3} for cave dwellings. To classify the dwellings in respect to their cave-character, the fraction of walls having a direct contact to the loess is calculated for each dwelling. While the {sup 222}Rn concentrations are increasing with higher fractions, the {sup 220}Rn concentrations are not correlated with this fraction. On the other hand, due to the short half-life of {sup 220}Rn the distance from the measuring point to the walls is negatively correlated with the {sup 220}Rn concentration, while there is no correlation with the {sup 222}Rn concentration. Therefore, concentric isolines of {sup 220}Rn concentrations showing a strong gradient were detected in cave dwellings. An influence of the ventilation rate is distinct for {sup 222}Rn but weak for {sup 220}Rn. The effective dose rates for {sup 222}Rn and {sup 220}Rn and their progenies are calculated for brick houses (2.7 mSv y{sup {minus}1}), cave dwellings (7.1 mSv y{sup {minus}1}), and for traditional cave dwellings with a bed foundation built with loess (16.7 mSv y{sup {minus}1}). These calculations are based on summer measurements only. It is expected that the true effective dose rates will be significantly higher.

  4. Identification of flood events inside karst cavities: Fria Cave (Asturias - NW Spain)

    NASA Astrophysics Data System (ADS)

    Gonzalez Lemos, Saul; Stoll, Heather

    2013-04-01

    Fluvial records may be well preserved in subterranean karst drainage networks and fluvial deposits cemented in speleothems may provide good chronology of past flood events. In several karst systems in Asturias (NW. Spain), moments of extreme precipitation events produce deposits from flood events in the bed and walls of caves which we propose are also recorded in the calcium carbonate stalagmites growing in the cave. The final stretch of the studied cave (Fria Cave), with a development of 360 m in length, intersects a small perennial stream which in our observation has maintained a minimum discharge of about 0.022 m3/s but periodically overflows into the vadose cave passage. Immediately after a flood overflow event, water marks and foam detritus are visible at various levels on the cave walls and corresponding to heights of bottlenecks in overflow drainage through the cave passage. Flood events deposit sand on terraces on the cave wall and move large volumes of sand in the cave bed. These extreme events leave a long-term record in i) wall coloration or water marks on the cave walls; and ii) detrital particles preserved as inclusions inside the stalagmites. Throughout this cave, it is possible to recognize chromatic changes in the walls, such as manganese oxide stains, which coincide with one of the water marks left during a recent flood event. The most salient manganese oxide on the walls rises up to 1.5 m measured from the thalweg and we interpreted it as the result of a frequent process of wetting - drying related to frequent flooding of the cave. Since 3-4 ka, drapery flowstone has been deposited over this oxide coating in some parts of the cave and the drapery remains free of oxide coating. We interpret this as indicating a reduction in the frequency and/or duration of flooding to this height, coincident with a regional drying trend in late Holocene. Stalagmites growing in the bed of the cave appear to trap fluvial sediments like sand or silts particles, which

  5. Origin and Evolution of Limestone Caves of Chhattisgarh and Orissa, India: Role of Geomorphic, Tectonic and Hydrological Processes

    NASA Astrophysics Data System (ADS)

    Gautam, P. K.; Allu, N. C.; Ramesh, R.; Yadava, M. G.; Panigrahi, C. P.

    2014-12-01

    Carbonate rocks undergo karstic process and karst morphology is a key to understand the nature and genesis of caves. The primary energy source for the formation of karst landforms is hydrological cycle. Geomorphic features along with hydrological characteristics provide important information not only on karst formation but also climate and environmental conditions. In this paper, we present the tectonic and geomorphic features that played a role in evolution of caves located in Chhattisgarh and Orissa States of India. The geomorphic and tectonic aspects of Kotumsar, Kailash, and Gupteshwar caves are discussed in relation to the origin and evolution of these caves. Caves are located near the water falls. The area is folded and faulted along the Eastern Ghat Mobile Belt (EGMB) due to tectonic reactivation. Shaly-limestone beds exhibit vertical dipping near Gupteshwar cave, and steeply inclined near Kotumsar and Kailash caves. Indrāvati and Sabari/Kolab tributaries of the Godavari River drain the area. The landscape evolution and the origin of caves in the region is a multistage process, where the lithology, orogeny, fluvial action, and monsoon are the main agents, which is similar to the four state model (Ford and Ewers, 1978). The river basin evolution and regional tectonism also caused the initiation of karstification in the region. The evolution of caves is believed to have taken place in Pre-Pliocene under more humid conditions that coincided with the initiation of monsoon in India. Further, during the Quaternary wet-dry/cold-warm phases altered physical and chemical weathering of limestone rocks. Contrasting relief features of Bastar plateau have also helped the extensive cave formation in the region. The dissolution along weak planes initiated the openings of caves, further enlarged by geomorphic agents. Both monsoon and tectonics have caused fluctuations in water levels along river courses, which acted as active agents in evolution of caves.

  6. Lava Flow at Kilauea, Hawaii

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On July 21, 2007, the world's most active volcano, Kilauea on Hawaii's Big Island, produced a new fissure eruption from the Pu'u O'o vent, which fed an open lava channel and lava flows toward the east. Access to the Kahauale'a Natural Area Reserve was closed due to fire and gas hazards. The two Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) nighttime thermal infrared images were acquired on August 21 and August 30, 2007. The brightest areas are the hottest lava flows from the recent fissure eruption. The large lava field extending down to the ocean is part of the Kupaianaha field. The most recent activity there ceased on June 20, but the lava is still hot and appears bright on the images. Magenta areas are cold lava flows from eruptions that occurred between 1969 and 2006. Clouds are cold (black) and the ocean is a uniform warm temperature, and light gray in color. These images are being used by volcanologists at the U.S. Geological Survey Hawaii Volcano Observatory to help monitor the progress of the lava flows.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra spacecraft. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud

  7. Evolution of Hang Son Doong, Vietnam: the largest cave passage in the world

    NASA Astrophysics Data System (ADS)

    Granger, D. E.

    2011-12-01

    Hang Son Doong (HSD), or Mountain River Cave, in the Quang Binh province of Vietnam, is considered to be the largest cave passage in the world. It has continuous widths near 100 m, and heights locally exceeding 200 m in a passage >6.5 km long. HSD is one of many extremely large caves in the tropical karst of the Ke Bang massif, a massively bedded limestone surrounded by metamorphic and clastic sedimentary rocks. Why are these caves so large? Is it because they are young and rapidly formed, or instead did they form slowly in exceptionally strong bedrock? To address these questions it is necessary to examine the style and timing of speleogenesis. Hang Son Doong was formed by an allogenic river sinking along a straight subvertical fault. The cave is formed largely within a brecciated fault zone that extends up to 100 m wide. A relict karst valley indicates that speleogenesis occurred due to wholesale capture of the surface river. The cave pattern is strongly fault-controlled with few branches, consistent with a primarily allogenic rather than distributed recharge. The cave is punctuated by two collapse dolines, one of which impedes discharge today. Massive slackwater deposits perhaps 100 m thick accumulated upstream of this doline collapse, and are overlain by corroded flowstone. To place some time constraints on speleogenesis, two samples were collected for cosmogenic nuclide burial dating with 26Al and 10Be in allogenic quartz. One was from the slackwater deposits, and another from a breccia-filled tributary passage at a fault junction. Both samples postdate cave formation, and can only be used to place minimum ages on the cave. Cosmogenic nuclide concentrations are very low, leading to large uncertainties in the ages. Nonetheless, the burial ages yield some important information. Initial results indicate that the slackwater deposits formed recently, during the past 300 ky. The filled passage, on the other hand, is much older and dates to the Pliocene. Re

  8. Exploring old caves

    NASA Astrophysics Data System (ADS)

    Luana Belli, Maria

    2015-04-01

    Quarries, caves and mines often contain fossils. During the '30s in Rome, the urban expansion needs for building materials such as gravel, sand and clay were extracted from quarries that surrounded the city. One of these quarries in particular, in the area of Saccopastore (Nomentana area 3 km from the University Sapienza Roma) returned an ancient human fossil skull belonging to a Neanderthal (most likely a female) who lived in Latium about 120,000 years ago. Detailed studies of this fossil were carried out by Sergio Sergi, the son of the founder of the Museum of Anthropology in Rome, Giuseppe Sergi. The museum was founded in 1884 and was later transferred to the University City (1934) where it is still located. Professor Maria Luana Belli, a science teacher in the Liceo Scientifico "G. Keplero" is a volunteer and collaborator with the Museum "G. Sergi", and she and her students retrace the places of the discovery on the trail of the Neanderthals, for understanding the evolution of the territory in a perspective of interdisciplinary teaching.

  9. Basaltic caves at Craters of the Moon National Monument and Preserve as analogs for Mars

    NASA Astrophysics Data System (ADS)

    Hinman, N. W.; Richardson, C. D.; McHenry, L.; Scott, J. R.

    2010-12-01

    Basaltic caves and lava tubes offer stable physicochemical conditions for formation of secondary minerals. Such features, putatively observed on Mars, intercept groundwater to weather country rock, leading to formation of secondary minerals. Further, caves are stable environments to search for evidence of past life, as they could offer protection from the oxidizing martian atmosphere. Searching for signs of life in a cave that could protect bio/organic compounds would preclude the need for risky drilling on Mars. Craters of the Moon National Monument (COM) offers an opportunity to study caves in Holocene iron-rich basalt flows to characterize secondary mineral deposits and search for organic compounds associated with secondary minerals; COM basalts are a good analog for martian basalts because of their high iron but other elements are higher at COM than on Mars. The Blue Dragon flow (~2.1 ka) contains the majority of the accessible caves and lava tubes. Two types of secondary mineral deposits were observed in these caves: ceiling coatings and crack or floor precipitates. Hematite, silica, and calcite comprise ceiling coatings. The crack and floor precipitates are white, efflorescent deposits in cavities along cave walls and ceilings or in localized mounds on cave floors. The secondary minerals in crack and floor precipitates are mainly thenardite and mirabilite with some minor concentrations of trona and/or burkeite. Organic compounds were found associated with the efflorescent deposits. Formation of the deposits is likely due to chemical leaching of basalt by meteoritic water. To test this, fluids collected from the ceiling and walls of the caves were analyzed. Solutions were modeled with the geochemical code, PHREEQC. The model tracked composition as water evaporated. Selected minerals were allowed to precipitate as they became oversaturated. Among the first minerals to become oversaturated were quartz and calcite, which are observed in ceiling deposits. Iron

  10. Mapping Overburden and Cave Networks with Muons

    NASA Astrophysics Data System (ADS)

    Prettyman, T. H.; Titus, T. N.; Boston, P. J.; Koontz, S. L.; Miller, R. S.

    2015-10-01

    We describe the use of highly-penetrating muons produced by cosmic ray showers to measure overburden and image the rock formation around terrestrial/extraterrestrial caves, and implications for cave science, exploration, and habitation.

  11. Unique Biosignatures in Caves of All Lithologies

    NASA Astrophysics Data System (ADS)

    Boston, P. J.; Schubert, K. E.; Gomez, E.; Conrad, P. G.

    2015-10-01

    Unique maze-like microbial communities on cave surfaces on all lithologies all over the world are an excellent candidate biosignatures for life detection missions into caves and other extraterrestrial environments.

  12. LavaSIM: the effect of heat transfer in 3D on lava flow characteristics (Invited)

    NASA Astrophysics Data System (ADS)

    Fujita, E.

    2013-12-01

    Characteristics of lava flow are governed by many parameters like lava viscosity, effusion rate, ground topography, etc. The accuracy and applicability of lava flow simulation code is evaluated whether the numerical simulation can reproduce these features quantitatively, which is important from both strategic and scientific points of views. Many lava flow simulation codes are so far proposed, and they are classified into two categories, i.e., the deterministic and the probabilistic models. LavaSIM is one of the former category models, and has a disadvantage of time consuming. But LavaSIM can solves the equations of continuity, motion, energy by step and has an advantage in the calculation of three-dimensional analysis with solid-liquid two phase flow, including the heat transfer between lava, solidified crust, air, water and ground, and three-dimensional convection in liquid lava. In other word, we can check the detailed structure of lava flow by LavaSIM. Therefore, this code can produce both channeled and fan-dispersive flows. The margin of the flow is solidified by cooling and these solidified crusts control the behavior of successive lava flow. In case of a channel flow, the solidified margin supports the stable central main flow and elongates the lava flow distance. The cross section of lava flow shows that the liquid lava flows between solidified crusts. As for the lava extrusion flow rate, LavaSIM can include the time function as well as the location of the vents. In some cases, some parts of the solidified wall may be broken by the pressure of successive flow and/or re-melting. These mechanisms could characterize complex features of the observed lava flows at many volcanoes in the world. To apply LavaSIM to the benchmark tests organized by V-hub is important to improve the lava flow evaluation technique.

  13. Numerical modelling of impact crater formation associated with isolated lunar skylight candidates on lava tubes

    NASA Astrophysics Data System (ADS)

    Martellato, E.; Foing, B. H.; Benkhoff, J.

    2013-09-01

    Skylights are openings on subsurface voids as lava tubes and caves. Recently deep hole structures, possibly skylights, were discovered on lunar photo images by the JAXA SELenological and ENgineering Explorer (SELENE)-Kaguya mission, and successively confirmed by the NASA Lunar Reconnaissance Orbiter (LRO) mission. Vertical hole structures and possibly underlying subsurface voids have high potential as resources for scientific study, and future unmanned and manned activities on the Moon. One mechanism proposed for their formation is impact cratering. The collapse of craters is due to the back spallation phenomena on the rear surface of the lava tube roofs. Previous analysis in this topic was based on small-scales laboratory experiments. These have pointed out that (i) the target thickness-to-crater diameter ratio is 0.7, and (ii) the projectile diameter-to-target thickness ratio is 0.16, at the ballistic limit once extrapolated to planetary conditions.

  14. Factors controlling lava dome morphology

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan; Bridges, Nathan; Griffiths, Ross

    1991-01-01

    Research suggests that variations in lava dome morphology on different planets will depend much more critically on local gravity and the style of eruption than on the magma composition, ambient temperature, or the relative roles of convective and radiative cooling. Eruption style in turn reflects differences in tectonic conditions and the ability of magma to exsolve volatiles. Observed crude correlations between silica content and calculated yield strengths for terrestrial lava flows and domes probably are do to differences in extrusion rate and volatile solubility, rather than intrinsic rheological properties. Thus, even after taking the known effect of gravity into account, observed differences in gross dome morphology on different planets cannot by themselves be directly related to composition. Additional information such as the distribution of surface textures and structures, or spectroscopic data will be needed to conclusively establish dome compositions.

  15. Cave Art: Reflections of Early Human Culture.

    ERIC Educational Resources Information Center

    Sullivan, Brother Nicholas

    1981-01-01

    Discusses Paleolithic and Neolithic cave art and artifacts, stressing the degree of intellectual ability exhibited by the creators of this art. Topics discussed include some misunderstandings about cave art intellect shown by cave artists and the use of light and color. (DS)

  16. Lava Flows around Olympus Mons

    NASA Technical Reports Server (NTRS)

    2002-01-01

    [figure removed for brevity, see original site]

    At first glance, this image of lava flows around the large scarp of Olympus Mons shows little contrast in surface materials due to dust cover, but a closer look reveals textures characteristic of the variable surface roughness associated with different lava flows in this region. The lobate edges of the flows are distinctive, and permit the discrimination of many overlapping individual flows. On small scales, the surfaces of some flows look wrinkly and ropy, indicating a relatively fluid type of lava flow referred to as pahoehoe. Other surfaces appear more rough and broken, and might be referred to as a'a flows, which have higher viscosities and effusion rates compared to pahoehoe flows. The surface textures of lava flows can thus sometimes be used for comparative purposes to infer lava viscosity and effusion rates. There is also a bright streak in the wind shadow of the impact crater in the lower left of the image where dust that settles onto the surface is not easily scoured away.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and

  17. Fish Assemblages of Mediterranean Marine Caves

    PubMed Central

    Bussotti, Simona; Di Franco, Antonio; Francour, Patrice; Guidetti, Paolo

    2015-01-01

    Fish assemblages associated with 14 marine caves and adjacent external rocky reefs were investigated at four Marine Protected Areas (MPAs) along the coasts of Italy. Within the caves sampling was carried out in different sub-habitats: walls, ceilings, bottoms and ends of caves. On the whole, 38 species were recorded inside the 14 caves investigated. Eighteen species were exclusively found inside the caves: they were mainly represented by speleophilic (i.e. species preferentially or exclusively inhabiting caves) gobids (e.g. Didogobius splechtnai) and nocturnal species (e.g. Conger conger). Forty-one species were censused outside, 20 of which were shared with cave habitats. Apogon imberbis was the most common fish found in all 14 caves investigated, followed by Thorogobius ephippiatus (recorded in 13 caves), and Diplodus vulgaris and Scorpaena notata (both censused in 12 caves). Distinct fish assemblages were found between external rocky reefs and the different cave sub-habitats. New data on the distribution of some speleophilic gobids were collected, showing the existence of a pool of species shared by marine caves on a large scale (i.e. hundreds of km). Considering the uniqueness of cave fishes (18 exclusive species and different assemblage structures), the inclusion of marine caves among the habitats routinely investigated for fish biodiversity monitoring could facilitate the achievement of more comprehensive inventories. Due to their contribution to local species diversity and the shelter they provide to species valuable for conservation, marine caves should be prioritized for their inclusion not only within future MPAs through the Mediterranean Sea, but also into larger management spatial planning. PMID:25875504

  18. Fragmentation Mechanisms Associated with Lacustrine Lava-Water Explosions

    NASA Astrophysics Data System (ADS)

    Fitch, E. P.; Fagents, S. A.; Thordarson, T.; Hamilton, C.

    2015-12-01

    Rootless cones form when degassed lava interacts explosively with water contained in the near-surface substrate, and represents an end-member system that can elucidate mechanisms of magma-water interactions due to the absence of primary degassing-induced fragmentation. The proportion of finely fragmented ejecta (i.e. ash), generated in rootless explosions, even if the volume is small relative to coarser ejecta, may contribute significantly to the explosion energy release. Explosive melt-water experiments indicate that the degree of melt-water mixing and energy release are proportional to the abundance of blocky grains, fragmented by brittle disintegration, which effectively contribute thermal energy to the explosive lava-water interaction. In order to determine the state of the lava at the point of ash-grade fragmentation in rootless explosions we examined grain morphology over the following size ranges: 0.5-0 ϕ (1.41-1 mm, very coarse ash), 1.5-2 ϕ (0.354-0.250 mm, medium ash), and 3.5-4 ϕ (0.088-0.062 mm, very fine ash). We found that rootless ash is composed of blocky, mossy, and fluidal grains with a minor component of aggregates (≤ 2%) and glassy shards (< 35%). Typically, (1) very coarse ash contains blocky (9-58%), mossy (8-36%) and fluidal (28-67%) grains only, (2) medium ash contains blocky (32-76%), mossy (9-39%) and fluidal (15-43%) grains with a minor abundance of glassy shards (≤ 8%), and (3) very fine ash is dominated by blocky clasts (53-80%), with lower shard (12-34%) and fluidal (4-24%) components. We observe that the abundance of fluidal grains decreases while the abundance of blocky grains increases with decreasing grain size. Also, the abundance of blocky grains decreases with increasing stratigraphic height, indicating that as rootless explosions progressed, brittle fragmentation of lava is less pronounced, suggesting that the efficiency of lava-water mixing dropped, most likely due to reduced availability of external water. However, we

  19. The probability of lava inundation at the proposed and existing Kulani prison sites

    USGS Publications Warehouse

    Kauahikaua, J.P.; Trusdell, F.A.; Heliker, C.C.

    1998-01-01

    The State of Hawai`i has proposed building a 2,300-bed medium-security prison about 10 km downslope from the existing Kulani medium-security correctional facility. The proposed and existing facilities lie on the northeast rift zone of Mauna Loa, which last erupted in 1984 in this same general area. We use the best available geologic mapping and dating with GIS software to estimate the average recurrence interval between lava flows that inundate these sites. Three different methods are used to adjust the number of flows exposed at the surface for those flows that are buried to allow a better representation of the recurrence interval. Probabilities are then computed, based on these recurrence intervals, assuming that the data match a Poisson distribution. The probability of lava inundation for the existing prison site is estimated to be 11- 12% in the next 50 years. The probability of lava inundation for the proposed sites B and C are 2- 3% and 1-2%, respectively, in the same period. The probabilities are based on estimated recurrence intervals for lava flows, which are approximately proportional to the area considered. The probability of having to evacuate the prison is certainly higher than the probability of lava entering the site. Maximum warning times between eruption and lava inundation of a site are estimated to be 24 hours for the existing prison site and 72 hours for proposed sites B and C. Evacuation plans should take these times into consideration.

  20. Accelerator 14C dates for early upper paleolithic (basal Aurignacian) at El Castillo Cave (Spain)

    USGS Publications Warehouse

    Valdes, V.C.; Bischoff, J.L.

    1989-01-01

    Three fragments of charcoal taken from different parts of the lowermost bed containing Aurignacian artifacts at El Castillo Cave yielded AMS dates of 37??7 (?? 1??8) ka bp, 38??5 (?? 1??8) ka bp, and 40??0 (?? 2??1) ka bp (average 38??7 ?? 1??9 ka bp). These dates are almost identical to new AMS dates from l'Arbreda cave in Catalunya on the same cultural horizon (average 38??5 ?? 1??0 ka bp) and are significantly older than the earliest dates for Aurignacian industries in the Aquitaine and in other parts of Central and Western Europe. ?? 1989.

  1. Emplacement of Long Lava Flows: Detailed Topography of the Carrizozo Basalt Lava Flow, New Mexico

    NASA Technical Reports Server (NTRS)

    Zimbelman, J. R; Johnston, A. K.

    2000-01-01

    The Carrizozo flow in south-central New Mexico was examined to obtain detailed topography for a long basaltic lava flow. This information will be helpful in evaluating emplacement models for long lava flows.

  2. Utility of Lava Tubes on Other Worlds

    NASA Astrophysics Data System (ADS)

    Walden, Bryce E.; Billings, T. L.; York, Cheryl Lynn; Gillett, S. L.; Herbert, M. V.

    1998-01-01

    On Mars, as on Earth, lava tubes are found in the extensive lava fields associated with shield volcanism. Lunar lava-tube traces are located near mare-highland boundaries, giving access to a variety of minerals and other resources, including steep slopes, prominent heights for local area communications and observation, large-surface areas in shade, and abundant basalt plains suitable for landing sites, mass-drivers, surface transportation, regolith harvesting, and other uses. Methods for detecting lava tubes include visual observations of collapse trenches and skylights, ground-penetrating radar, gravimetry, magnetometry, seismography, atmospheric effects, laser, lidar, infrared, and human or robotic exploration.

  3. What factors control superficial lava dome explosivity?

    PubMed Central

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît; Morgan, Daniel J.

    2015-01-01

    Dome-forming eruption is a frequent eruptive style and a major hazard on numerous volcanoes worldwide. Lava domes are built by slow extrusion of degassed, viscous magma and may be destroyed by gravitational collapse or explosion. The triggering of lava dome explosions is poorly understood: here we propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite precipitation. Both processes generate an impermeable and rigid carapace allowing overpressurisation of the inner parts of the lava dome by the rapid input of vesiculated magma batches. The relative thickness of the cristobalite-rich carapace is an inverse function of the external lava dome surface area. Explosive activity is thus more likely to occur at the onset of lava dome extrusion, in agreement with observations, as the likelihood of superficial lava dome explosions depends inversely on lava dome volume. This new result is of interest for the whole volcanological community and for risk management. PMID:26420069

  4. What factors control superficial lava dome explosivity?

    NASA Astrophysics Data System (ADS)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoît; Morgan, Daniel J.

    2015-09-01

    Dome-forming eruption is a frequent eruptive style and a major hazard on numerous volcanoes worldwide. Lava domes are built by slow extrusion of degassed, viscous magma and may be destroyed by gravitational collapse or explosion. The triggering of lava dome explosions is poorly understood: here we propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite precipitation. Both processes generate an impermeable and rigid carapace allowing overpressurisation of the inner parts of the lava dome by the rapid input of vesiculated magma batches. The relative thickness of the cristobalite-rich carapace is an inverse function of the external lava dome surface area. Explosive activity is thus more likely to occur at the onset of lava dome extrusion, in agreement with observations, as the likelihood of superficial lava dome explosions depends inversely on lava dome volume. This new result is of interest for the whole volcanological community and for risk management.

  5. 36 CFR 290.4 - Confidentiality of cave location information.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Confidentiality of cave... AGRICULTURE CAVE RESOURCES MANAGEMENT § 290.4 Confidentiality of cave location information. (a) Information... location of a significant cave or a cave nominated for designation, unless the authorized...

  6. 36 CFR 290.4 - Confidentiality of cave location information.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Confidentiality of cave... AGRICULTURE CAVE RESOURCES MANAGEMENT § 290.4 Confidentiality of cave location information. (a) Information... location of a significant cave or a cave nominated for designation, unless the authorized...

  7. 36 CFR 290.4 - Confidentiality of cave location information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Confidentiality of cave... AGRICULTURE CAVE RESOURCES MANAGEMENT § 290.4 Confidentiality of cave location information. (a) Information... location of a significant cave or a cave nominated for designation, unless the authorized...

  8. 36 CFR 290.4 - Confidentiality of cave location information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 2 2010-07-01 2010-07-01 false Confidentiality of cave... AGRICULTURE CAVE RESOURCES MANAGEMENT § 290.4 Confidentiality of cave location information. (a) Information... location of a significant cave or a cave nominated for designation, unless the authorized...

  9. 36 CFR 290.4 - Confidentiality of cave location information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Confidentiality of cave... AGRICULTURE CAVE RESOURCES MANAGEMENT § 290.4 Confidentiality of cave location information. (a) Information... location of a significant cave or a cave nominated for designation, unless the authorized...

  10. DELINEATING KARST RECHARGE AREAS AT ONONDAGA CAVE STATE PARK

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Onondaga Cave State Park is located in the north central portion of the Ozarks near Leasburg, Missouri. The park is known for two extensive cave systems, Onondaga Cave and Cathedral Cave. Both of these cave systems have active streams (1-2 cfs at baseflow) which have unknown recharge areas. As a man...

  11. The Stability of Lava Lakes

    NASA Astrophysics Data System (ADS)

    Witham, F.; Llewellin, E. W.; Woods, A. W.; Gladstone, C.

    2007-12-01

    Lava lakes may exhibit complex cycles of filling and draining on time-scales of hours to weeks. Such activity is recorded at Pu`u `O`o, Hawai`i. Other examples, e.g. Erta Ale in Ethiopia, do not display these draining episodes; instead an 'equilibrium' system is observed in which the lake may persist for years. We present the results of a theoretical and experimental investigation of lava lakes and identify behavioural regimes distinguished by system geometry and gas content. Laboratory analogue modelling shows that even a simple conduit-lake system, driven by a constant gas flux, can display steady-state equilibrium or cyclic behaviour, depending on the rate of gas flux. A theoretical approach to the same system captures this range of behaviour. By testing the stability of an 'equilibrium' lake to small perturbations, we show that the degree of stability is controlled by the ratio of conduit to lake areas, and the gas volume fraction at the top of the conduit. Despite the simplicity of the modelled system, a rich spectrum of behaviour is found. The model predicts that a stable system must drain over time. This implies that lakes which exhibit ongoing degassing for years or decades (e.g. Erta Ale) either must have an exogenous supply of gas bubbles from depth, or an effective conduit convection mechanism must exist.

  12. Propagation style controls lava-snow interactions

    NASA Astrophysics Data System (ADS)

    Edwards, B. R.; Belousov, A.; Belousova, M.

    2014-12-01

    Understanding interactions between volcanic eruptions and the cryosphere (a.k.a. glaciovolcanism) is important for climate reconstructions as well as for hazard mitigation at ice-clad volcanoes. Here we present unique field observations of interactions between snowpack and advancing basaltic lava flows during the 2012-13 eruption at Tolbachik volcano, Kamchatka, Russia. Our observations show that lava-snow heat transfer is slow, and that styles of lava propagation control snowpack responses. ‧A‧a and sheet lava flows advance in a rolling caterpillar-track motion on top of the rigid, snowpack substrate with minor lava-snow interaction. In contrast, pahoehoe lava propagates by inflation of lobes beneath/inside the snowpack, producing rigorous lava-snow interaction via meltwater percolation down into the incandescent lava causing production of voluminous steam, rapid surface cooling and thermal shock fragmentation. The textures produced by pahoehoe-snowpack interactions are distinctive and, where observed at other sites, can be used to infer syn-eruption seasonality and climatic conditions.

  13. Propagation style controls lava-snow interactions.

    PubMed

    Edwards, B R; Belousov, A; Belousova, M

    2014-01-01

    Understanding interactions between volcanic eruptions and the cryosphere (a.k.a. glaciovolcanism) is important for climate reconstructions as well as for hazard mitigation at ice-clad volcanoes. Here we present unique field observations of interactions between snowpack and advancing basaltic lava flows during the 2012-13 eruption at Tolbachik volcano, Kamchatka, Russia. Our observations show that lava-snow heat transfer is slow, and that styles of lava propagation control snowpack responses. 'A'a and sheet lava flows advance in a rolling caterpillar-track motion on top of the rigid, snowpack substrate with minor lava-snow interaction. In contrast, pahoehoe lava propagates by inflation of lobes beneath/inside the snowpack, producing rigorous lava-snow interaction via meltwater percolation down into the incandescent lava causing production of voluminous steam, rapid surface cooling and thermal shock fragmentation. The textures produced by pahoehoe-snowpack interactions are distinctive and, where observed at other sites, can be used to infer syn-eruption seasonality and climatic conditions. PMID:25514031

  14. Emplacement of Xenolith Nodules in the Kaupulehu Lava Flow, Hualalai Volcano, Hawaii

    NASA Technical Reports Server (NTRS)

    Guest, J. E.; Spudis, P. D.; Greeley, R.; Taylor, G. J.; Baloga, S. M.

    1995-01-01

    The basaltic Kaupulehu 1800-1801 lava flow of Hualalai Volcano, Hawaii contains abundant ultramafic xenoliths. Many of these xenoliths occur as bedded layers of semi-rounded nodules, each thinly coated with a veneer (typically 1 mm thick) of lava. The nodule beds are analogous to cobble deposits of fluvial sedimentary systems. Although several mechanisms have been proposed for the formation of the nodule beds, it was found that, at more than one locality, the nodule beds are overbank levee deposits. The geological occurrence of the nodules, certain diagnostic aspects of the flow morphology and consideration of the inferred emplacement process indicate that the Kaupulehu flow had an exceptionally low viscosity on eruption and that the flow of the lava stream was extremely rapid, with flow velocities of at least 10 m/s (more than 40 km/h. This flow is the youngest on Hualalai Volcano and future eruptions of a similar type would pose considerable hazard to life as well as property.

  15. Internal fabric development in complex lava domes

    NASA Astrophysics Data System (ADS)

    Závada, Prokop; Kratinová, Zuzana; Kusbach, Vladimír; Schulmann, Karel

    2009-03-01

    Viscous lava extrusions were modeled using plaster of Paris with admixed magnetite dust which served as a tracer of the internal anisotropy of magnetic susceptibility fabric in model lava domes. Used analogue material showed pseudoplastic behavior and yield strength level proportional to increasing mixing ratio of plaster powder and water. A series of models ranging from simple gravity flows to complex lava domes showing combined endogenous and exogenous growth were created by intrusion of plaster into a sandbox. The similarity of model bodies is compared with natural lava domes on the basis of dynamic scaling analysis. Growth dynamics, exogenous growth and internal fabric development in natural lava domes is critically discussed using the experimental results.

  16. Using CAVE technology for functional genomics studies.

    PubMed

    Sensen, Christoph W

    2002-01-01

    We have established the first Java 3D-enabled CAVE (CAVE automated virtual environment). The Java application programming interface allows the complete separation of the program development from the program execution, opening new application domains for the CAVE technology. Programs can be developed on any Java-enabled computer platform, including Windows, Macintosh, and Linux workstations, and executed in the CAVE without modification. The introduction of Java, one of the major programming environments for bioinformatics, into the CAVE environment allows the rapid development applications for genome research, especially for the analysis of the spatial and temporal data that are being produced by functional genomics experiments. The CAVE technology will play a major role in the modeling of biological systems that is necessary to understand how these systems are organized and how they function. PMID:12614491

  17. From Cave Walls to Clay Images

    ERIC Educational Resources Information Center

    Stone, Julie

    2004-01-01

    About 15,000 BC, the bison and other animals roamed the land and cave people, in their spare time, found colorful, chalky rocks with which to play. Over the course of time, they found that the chalky rocks would rub off on the cave walls, thus cave paintings and the pursuit of art was born. This article describes one fourth-grade classroom's…

  18. Cave of the Astronomers at Xochicalco

    NASA Astrophysics Data System (ADS)

    Lebeuf, Arnold

    The chimney built in the roof of the artificial large cave at Xochicalco, known as "Cave of the astronomers", has been interpreted as a solar zenithal observation tube. Nevertheless, different elements and especially the latitude of the site itself led the author to present a lunar hypothesis. Precise measurements of the impact of light inside the cave show the degree of precision that can be obtained in this camera obscura.

  19. Computer Assisted Virtual Environment - CAVE

    SciTech Connect

    Erickson, Phillip; Podgorney, Robert; Weingartner, Shawn; Whiting, Eric

    2014-01-14

    Research at the Center for Advanced Energy Studies is taking on another dimension with a 3-D device known as a Computer Assisted Virtual Environment. The CAVE uses projection to display high-end computer graphics on three walls and the floor. By wearing 3-D glasses to create depth perception and holding a wand to move and rotate images, users can delve into data.

  20. Computer Assisted Virtual Environment - CAVE

    ScienceCinema

    Erickson, Phillip; Podgorney, Robert; Weingartner, Shawn; Whiting, Eric

    2014-06-09

    Research at the Center for Advanced Energy Studies is taking on another dimension with a 3-D device known as a Computer Assisted Virtual Environment. The CAVE uses projection to display high-end computer graphics on three walls and the floor. By wearing 3-D glasses to create depth perception and holding a wand to move and rotate images, users can delve into data.

  1. Lava Flows near Pavonis Mons

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 29 September 2003

    The Tharsis province of Mars was the main center of volcanism on the planet. This THEMIS visible image shows lava flows that appear to be originating from linear vents just east of Pavonis Mons, the middle of the three giant Tharsis volcanoes. A large volume of lava also appears to be flowing out of a smaller series of pits on the far eastern side of the image, towards the bottom.

    Image information: VIS instrument. Latitude 2.1, Longitude 253.1 East (106.9 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  2. Lava Flows and Surface Textures

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 17 November 2003

    The striking surface textures observed in this THEMIS image taken south of the volcano Arsia Mons are from different erupted lava flows. Many flows extend for several kilometers and are observed to crosscut previous existing flows. The variable surface textures could result from older and younger lava flows, differences in the composition and vessicularity of magma, or different degrees of weathering.

    Image information: VIS instrument. Latitude -20.4, Longitude 242.2 East (117.8 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  3. Dynamics of the Mount Nyiragongo lava lake

    NASA Astrophysics Data System (ADS)

    Burgi, P.-Y.; Darrah, T. H.; Tedesco, D.; Eymold, W. K.

    2014-05-01

    The permanent and presently rising lava lake at Mount Nyiragongo constitutes a major potential geological hazard to the inhabitants of the Virunga volcanic region in the Democratic Republic of Congo (DRC) and Rwanda. Based on two field campaigns in June 2010 and 2011, we estimate the lava lake level from the southeastern crater rim (~400 m diameter) and lava lake area (~46,550 m2), which constrains, respectively, the lava lake volume (~9 × 106 m3) and volume flow rate needed to keep the magma in a molten state (0.6 to 3.5 m3 s-1). A bidirectional magma flow model, which includes the characterization of the conduit diameter and funnel-shaped lava lake geometry, is developed to constrain the amount of magma intruded/emplaced within the magmatic chamber and rift-related structures that extend between Mount Nyiragongo's volcanic center and the city of Goma, DRC, since Mount Nyiragongo's last eruption (17 January 2002). Besides matching field data of the lava lake level covering the period 1977 to 2002, numerical solutions of the model indicate that by 2022, 20 years after the January 2002 eruption, between 300 and 1700 × 106 m3 (0.3 to 1.7 km3) of magma could have intruded/emplaced underneath the edifice, and the lava lake volume could exceed 15 × 106 m3.

  4. Lava flow texture LiDAR signatures

    NASA Astrophysics Data System (ADS)

    Whelley, P.; Garry, W. B.; Scheidt, S. P.; Irwin, R. P., III; Fox, J.; Bleacher, J. E.; Hamilton, C. W.

    2014-12-01

    High-resolution point clouds and digital elevation models (DEMs) are used to investigate lava textures on the Big Island of Hawaii. An experienced geologist can distinguish fresh or degraded lava textures (e.g., blocky, a'a and pahoehoe) visually in the field. Lava texture depends significantly on eruption conditions, and it is therefore instructive, if accurately determined. In places where field investigations are prohibitive (e.g., Mercury, Venus, the Moon, Mars, Io and remote regions on Earth) lava texture must be assessed from remote sensing data. A reliable method for differentiating lava textures in remote sensing data remains elusive. We present preliminary results comparing properties of lava textures observed in airborne and terrestrial Light Detection and Ranging (LiDAR) data. Airborne data, in this study, were collected in 2011 by Airborne 1 Corporation and have a ~1m point spacing. The authors collected the terrestrial data during a May 2014 field season. The terrestrial scans have a heterogeneous point density. Points close to the scanner are 1 mm apart while 200 m in the distance points are 10 cm apart. Both platforms offer advantages and disadvantages beyond the differences in scale. Terrestrial scans are a quantitative representation of what a geologist sees "on the ground". Airborne scans are a point of view routinely imaged by other remote sensing tools, and can therefore be quickly compared to complimentary data sets (e.g., spectral scans or image data). Preliminary results indicate that LiDAR-derived surface roughness, from both platforms, is useful for differentiating lava textures, but at different spatial scales. As all lava types are quite rough, it is not simply roughness that is the most advantageous parameter; rather patterns in surface roughness can be used to differentiate lava surfaces of varied textures. This work will lead to faster and more reliable volcanic mapping efforts for planetary exploration as well as terrestrial

  5. Modeling and analysis of caves using voxelization

    NASA Astrophysics Data System (ADS)

    Szeifert, Gábor; Szabó, Tivadar; Székely, Balázs

    2014-05-01

    Although there are many ways to create three dimensional representations of caves using modern information technology methods, modeling of caves has been challenging for researchers for a long time. One of these promising new alternative modeling methods is using voxels. We are using geodetic measurements as an input for our voxelization project. These geodetic underground surveys recorded the azimuth, altitude and distance of corner points of cave systems relative to each other. The diameter of each cave section is estimated from separate databases originating from different surveys. We have developed a simple but efficient method (it covers more than 99.9 % of the volume of the input model on the average) to convert these vector-type datasets to voxels. We have also developed software components to make visualization of the voxel and vector models easier. Since each cornerpoint position is measured relative to another cornerpoints positions, propagation of uncertainties is an important issue in case of long caves with many separate sections. We are using Monte Carlo simulations to analyze the effect of the error of each geodetic instrument possibly involved in a survey. Cross-sections of the simulated three dimensional distributions show, that even tiny uncertainties of individual measurements can result in high variation of positions that could be reduced by distributing the closing errors if such data are available. Using the results of our simulations, we can estimate cave volume and the error of the calculated cave volume depending on the complexity of the cave. Acknowledgements: the authors are grateful to Ariadne Karst and Cave Exploring Association and State Department of Environmental and Nature Protection of the Hungarian Ministry of Rural Development, Department of National Parks and Landscape Protection, Section Landscape and Cave Protection and Ecotourism for providing the cave measurement data. BS contributed as an Alexander von Humboldt Research

  6. Early life recorded in archean pillow lavas.

    PubMed

    Furnes, Harald; Banerjee, Neil R; Muehlenbachs, Karlis; Staudigel, Hubert; de Wit, Maarten

    2004-04-23

    Pillow lava rims from the Mesoarchean Barberton Greenstone Belt in South Africa contain micrometer-scale mineralized tubes that provide evidence of submarine microbial activity during the early history of Earth. The tubes formed during microbial etching of glass along fractures, as seen in pillow lavas from recent oceanic crust. The margins of the tubes contain organic carbon, and many of the pillow rims exhibit isotopically light bulk-rock carbonate delta13C values, supporting their biogenic origin. Overlapping metamorphic and magmatic dates from the pillow lavas suggest that microbial life colonized these subaqueous volcanic rocks soon after their eruption almost 3.5 billion years ago. PMID:15105498

  7. Bed bugs.

    PubMed

    Foulke, Galen T; Anderson, Bryan E

    2014-09-01

    The term bed bug is applied to 2 species of genus Cimex: lectularius describes the common or temperate bed bug, and hemipterus its tropical cousin. Cimex lectularius is aptly named; its genus and species derive from the Latin words for bug and bed, respectively. Though the tiny pest is receiving increased public attention and scrutiny, the bed bug is hardly a new problem. PMID:25577850

  8. Lava Flows in IR Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released August 5, 2004 This image shows two representations of the same infra-red image covering a portion of the Solis Planum region, southeast of the Tharsis volcanoes. On the left is a grayscale image showing surface temperature, and on the right is a false-color composite made from 3 individual THEMIS bands. The false-color image is colorized using a technique called decorrelation stretch (DCS), which emphasizes the spectral differences between the bands to highlight compositional variations.

    Multiple layers of lava flows in this region show temperature differences, as well as some potential compositional differences. The temperature variations between these flows are likely caused by differences in their surface texture. The compositional variation could be due to differences in the make-up of the lava when it erupted onto the surface or might only reflect differences in the amount of dust covering these flows.

    Image information: IR instrument. Latitude -30.1, Longitude 275.9 East (84.1 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is

  9. Gravity for Detecting Caves: Airborne and Terrestrial Simulations Based on a Comprehensive Karstic Cave Benchmark

    NASA Astrophysics Data System (ADS)

    Braitenberg, Carla; Sampietro, Daniele; Pivetta, Tommaso; Zuliani, David; Barbagallo, Alfio; Fabris, Paolo; Rossi, Lorenzo; Fabbri, Julius; Mansi, Ahmed Hamdi

    2016-04-01

    Underground caves bear a natural hazard due to their possible evolution into a sink hole. Mapping of all existing caves could be useful for general civil usages as natural deposits or tourism and sports. Natural caves exist globally and are typical in karst areas. We investigate the resolution power of modern gravity campaigns to systematically detect all void caves of a minimum size in a given area. Both aerogravity and terrestrial acquisitions are considered. Positioning of the gravity station is fastest with GNSS methods the performance of which is investigated. The estimates are based on a benchmark cave of which the geometry is known precisely through a laser-scan survey. The cave is the Grotta Gigante cave in NE Italy in the classic karst. The gravity acquisition is discussed, where heights have been acquired with dual-frequency geodetic GNSS receivers and Total Station. Height acquisitions with non-geodetic low-cost receivers are shown to be useful, although the error on the gravity field is larger. The cave produces a signal of -1.5 × 10-5 m/s2, with a clear elliptic geometry. We analyze feasibility of airborne gravity acquisitions for the purpose of systematically mapping void caves. It is found that observations from fixed wing aircraft cannot resolve the caves, but observations from slower and low-flying helicopters or drones do. In order to detect the presence of caves the size of the benchmark cave, systematic terrestrial acquisitions require a density of three stations on square 500 by 500 m2 tiles. The question has a large impact on civil and environmental purposes, since it will allow planning of urban development at a safe distance from subsurface caves. The survey shows that a systematic coverage of the karst would have the benefit to recover the position of all of the greater existing void caves.

  10. Management issues in a Tasmanian tourist cave: potential microclimatic impacts of cave modifications.

    PubMed

    Russell, Mick J; MacLean, Victoria L

    2008-05-01

    Caves can be difficult to navigate and often require physical modification to allow easy access for visitors. Single entrance caves double the access impact of each visitor. Visitors in tourist caves have direct physical effects such as the introduction of concrete and steel structures; transport of mud, dust, and nutrients; installation of lights and the exhalation of water vapour and carbon dioxide into the air. Indirect physical effects include alteration of the microclimate, both through physical modifications that change the ventilation regime and through the presence of visitors leading to changes in temperature, humidity and CO2 within the cave environment. Anthropomorphic changes to cave physical environments to aid access or to reduce backtracking can have adverse effects on the internal microclimate of cave systems with subsequent changes to the cave environment affecting the quality of decorations and cave art and the diversity of cave fauna. Although often stated that caves operate at or near a constant temperature, closer examination indicates that cave temperatures are neither static nor constant. The degree of variation depends largely on the structure and physical characteristics of the cave. Air temperature and humidity gradients between the inside and outside cave environment can result in air density differences, which create airflow, which will in turn affect the cave microclimate. As part of the development of a management framework for King Solomons Cave, Tasmania, a study of the microclimate was carried out on behalf of Tasmanian Parks and Wildlife Service. Analysis of the variables showed significant differences in air temperature within each site and between sites. These differences range from 4 degrees C variation at one site to 0 degrees C at another site. The data were used to model potential airflow between the cave and the external environment. Results indicate that part of the cave is dominated by airflow between the chimney and the

  11. The conservation of Britain's limestone cave resource

    NASA Astrophysics Data System (ADS)

    Hardwick, P.; Gunn, J.

    1996-10-01

    Limestone caves are an important scientific and recreational resource in Britain. During the mid- to late 1970s, cavers and statutory conservation bodies cooperated in a review of cave resources which resulted in the designation of 48 caves or cave areas as Sites of Special Scientific Interest (SSSI). During the same period, the Wildlife and Countryside Act 1981 was introduced to provide more effective planning controls on activities such as agriculture carried out within SSSI boundaries. In one case, at Priddy in the Mendip Hills of Somerset, landowners prevented access to a number of caves in protest over the new, tougher restrictions on agriculture. Faced with the closure, and perceiving that their recreational use of caves might also be controlled, local cavers joined the landowners in opposing the proposals for SSSI designation. As a result the proposals were reviewed, three caves were excluded from the site and controls on the remaining area were relaxed. The case emphasized a need for an effective system to take account of all factors affecting cave conservation, a need which has led to a more constructive dialogue between nature conservation bodies, caver organizations and other interested parties.

  12. Geomagnetic polarity zones for icelandic lavas

    USGS Publications Warehouse

    Dagley, P.; Wilson, R.L.; Ade-Hall, J. M.; Walker, G.P.L.; Haggerty, S.E.; Sigurgeirsson, T.; Watkins, N.D.; Smith, P.J.; Edwards, J.; Grasty, R.L.

    1967-01-01

    Analysis of cores collected from a sequence of lavas in Eastern Iceland has made possible an accurate calculation of the average rate of reversal of the Earth's magnetic field. ?? 1967 Nature Publishing Group.

  13. Geomorphic Classification of Lava Flows on Io

    NASA Technical Reports Server (NTRS)

    Pieri, D. C.

    1985-01-01

    The lava flows on Io are classified into the following categories: broad, filamental, digitate, intercalated, sheet, and contained. Each classification is described according to flow distribution, geomorphology, color, thickness, and source.

  14. Lunar lava tube radiation safety analysis.

    PubMed

    De Angelis, Giovanni; Wilson, J W; Clowdsley, M S; Nealy, J E; Humes, D H; Clem, J M

    2002-12-01

    For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith layer and rock. The chemical composition has been chosen as typical of the lunar regions where the largest number of lava tube candidates are found. Particles have been transported all through the regolith and the rock, and received particles flux and doses have been calculated. The radiation safety of lunar lava tubes environments has been demonstrated. PMID:12793728

  15. Lava Tube Exploration Robot and Payload Development

    NASA Astrophysics Data System (ADS)

    Kelly, H. S.; Parness, A. J.; Boston, P. J.

    2015-10-01

    Merging science and engineering from the ground up to co-develop a comprehensive instrument/robot package for exploration of and scientific data collection within lava tubes that target analog sites on the Moon and Mars.

  16. Lunar lava tube radiation safety analysis

    NASA Technical Reports Server (NTRS)

    De Angelis, Giovanni; Wilson, J. W.; Clowdsley, M. S.; Nealy, J. E.; Humes, D. H.; Clem, J. M.

    2002-01-01

    For many years it has been suggested that lava tubes on the Moon could provide an ideal location for a manned lunar base, by providing shelter from various natural hazards, such as cosmic radiation, meteorites, micrometeoroids, and impact crater ejecta, and also providing a natural environmental control, with a nearly constant temperature, unlike that of the lunar surface showing extreme variation in its diurnal cycle. An analysis of radiation safety issues on lunar lava tubes has been performed by considering radiation from galactic cosmic rays (GCR) and Solar Particle Events (SPE) interacting with the lunar surface, modeled as a regolith layer and rock. The chemical composition has been chosen as typical of the lunar regions where the largest number of lava tube candidates are found. Particles have been transported all through the regolith and the rock, and received particles flux and doses have been calculated. The radiation safety of lunar lava tubes environments has been demonstrated.

  17. Taylor instability in rhyolite lava flows

    NASA Technical Reports Server (NTRS)

    Baum, B. A.; Krantz, W. B.; Fink, J. H.; Dickinson, R. E.

    1989-01-01

    A refined Taylor instability model is developed to describe the surface morphology of rhyolite lava flows. The effect of the downslope flow of the lava on the structures resulting from the Taylor instability mechanism is considered. Squire's (1933) transformation is developed for this flow in order to extend the results to three-dimensional modes. This permits assessing why ridges thought to arise from the Taylor instability mechanism are preferentially oriented transverse to the direction of lava flow. Measured diapir and ridge spacings for the Little and Big Glass Mountain rhyolite flows in northern California are used in conjunction with the model in order to explore the implications of the Taylor instability for flow emplacement. The model suggests additional lava flow features that can be measured in order to test whether the Taylor instability mechanism has influenced the flows surface morphology.

  18. Mysterious Lava Mineral on Mars

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graph or spectrum captured by the Moessbauer spectrometer onboard the Mars Exploration Rover Spirit shows the presence of three different iron-bearing minerals in the soil at the rover's landing site. One of these minerals has been identified as olivine, a shiny green rock commonly found in lava on Earth. The other two have yet to be pinned down. Scientists were puzzled by the discovery of olivine because it implies the soil consists at least partially of ground up rocks that have not been weathered or chemically altered. The black line in this graph represents the original data; the three colored regions denote individual minerals and add up to equal the black line.

    The Moessbauer spectrometer uses two pieces of radioactive cobalt-57, each about the size of pencil erasers, to determine with a high degree of accuracy the composition and abundance of iron-bearing minerals in martian rocks and soil. It is located on the rover's instrument deployment device, or 'arm.'

  19. Geochemical aspects of some Japanese lavas.

    NASA Technical Reports Server (NTRS)

    Philpotts, J. A.; Martin, W.; Schnetzler, C. C.

    1971-01-01

    K, Rb, Sr, Ba and rare-earth concentrations in some Japanese lavas have been determined by mass-spectrometric stable-isotope dilution. The samples fall into three rare-earth groups corresponding to tholeiitic, high alumina and alkali basalts. Japanese tholeiites have trace element characteristics similar to those of oceanic ridge tholeiites except for distinctly higher relative concentrations of Ba. Japanese lavas may result from various degrees of partial fusion of amphibole eclogite.

  20. Keck Geology Consortium Lava Project: Undergraduate Research Linking Natural and Experimental Basaltic Lava Flows

    NASA Astrophysics Data System (ADS)

    Karson, J. A.; Hazlett, R. W.; Wysocki, R.; Bromfield, M. E.; Browne, N. C.; Davis, N. C.; Pelland, C. G.; Rowan, W. L.; Warner, K. A.

    2014-12-01

    Undergraduate students in the Keck Geology Consortium Lava Project participated in a month-long investigation of features of basaltic lava flows from two very different perspectives. The first half of the project focused on field relations in basaltic lava flows from the 1984 Krafla Fires eruption in northern Iceland. Students gained valuable experience in the collection of observations and samples in the field leading to hypotheses for the formation of selected features related to lava flow dynamics. Studies focused on a wide range of features including: morphology and heat loss in lava tubes (pyroducts), growth and collapse of lava ponds and overflow deposits, textural changes of lava falls (flow over steep steps), spaced spatter cones from flows over wet ground, and anisotropy of magnetic susceptibility related to flow kinematics. In the second half of the program students designed, helped execute, documented, and analyzed features similar to those they studied in the field with large-scale (50-250 kg) basaltic lava flows created in the Syracuse University Lava Project (http://lavaproject.syr.edu). Data collected included video from multiple perspectives, infrared thermal (FLIR) images, still images, detailed measurements of flow dimensions and rates, and samples for textural and magnetic analyses. Experimental lava flow features provided critical tests of hypotheses generated in the field and a refined understanding of the behavior and final morphology of basaltic lava flows. The linked field and experimental studies formed the basis for year-long independent research projects under the supervision of their faculty mentors, leading to senior theses at the students' respective institutions.

  1. Investigating lava-substrate interactions through flow experiments with syrup, wax, and molten basalt

    NASA Astrophysics Data System (ADS)

    Rumpf, M. E.; Lev, E.

    2015-12-01

    Among the many factors influencing the complex process of lava flow emplacement, the interaction with the substrate onto which flow is emplaced plays a central role. Lava flows are rarely emplaced onto smooth or regular surfaces. For example, at Kīlauea Volcano, Hawai'i, lava flows regularly flow over solid rock, vegetation, basaltic or silica sand, and man-made materials, including asphalt and concrete. In situ studies of lava-substrate interactions are inherently difficult, and often dangerous, to carry-out, requiring the design of controllable laboratory experiments. We investigate the effects of substrate grain size, cohesion, and roughness on flow mobility and morphology through a series of flow experiments using analog materials and molten basalt. We have developed a series of experiments that allow for adjustable substrate parameters and analyze their effects on lava flow emplacement. The first set of experiments are performed at the Fluids Mechanics Laboratory at the Lamont-Doherty Earth Observatory and focus on two analog materials: polyethylene glycol (PEG), a commercially available wax, and corn syrup. The fluids were each extruded onto a series of scaled substrate beds to replicate the emplacement of lava in a natural environment. Preliminary experiments demonstrated that irregular topography, particularly topography with a height amplitude similar to that of the flow itself, can affect flow morphology, width, and velocity by acting as local barriers or culverts to the fluid. This is expected from observations of fluid flow in natural environments. A follow-up set of experiments will be conducted in Fall 2015 at the Syracuse University (SU) Lava Project Lab. In this set, we will pour molten basalt directly onto a series of substrates representing natural environments found on the Earth and other rocky bodies in the Solar System. These experiments will allow for analysis of the effects of basaltic composition and high temperatures on lava-substrate heat

  2. ACCESS Mars: A Mission Architecture for an initial settlement on Mars; using caves as habitation

    NASA Astrophysics Data System (ADS)

    Perez-Poch, Antoni; Gallardo, Beatriz; Laufer, Ren; Zavaleta, Jhony; Davila, Alfonso; de Carufel, Guy; Antonakopoulos, Konstantinos; Husseini, A. Al; Alvarez Sánchez, L.; Antonakopoulos, K.; Apeldoorn, J.; Ashford, K., Jr.; Atabay, D.; Barrios, I.; Baydaroglu, Y.; Bennell, K. M.; Chen, J.; Chen, X.; Cormier, D.; Crowley, P.; de Carufel, G.; Deper, B.; Drube, L.; Duffy, P.; Edwards, P.; Gutiérrez Fernandez, E.; Haider, O.; Kumar, G.; Henselowsky, C.; Hirano, D.; Hirmer, T.; Hogan, B.; Albalat, A. Jaime; Jens, E.; Jivenescu, I.; Jojaghaian, A.; Kerrigan, M.; Kodachi, Y.; Langston, S.; Macintosh, R.; Miguélez, X.; Panek, N.; Pegg, C.; Peldszus, R.; Peng, X.; Perez-Poch, A.; Perron, A.; Qiu, J.; Renten, P.; Ricardo, J.; Saraceno, T.; Sauceda, F.; Shaghaghi Varzeghani, A.; Shimmin, R.; Solaz, R.; Solé, A.; Suresh, E. R.; Mar Vaquero Escribano, T.; Vargas Muñoz, M.; Vaujour, P. D.; Zeile, D. Veilette, Y. Winetraub, O.

    This paper summarizes a team project report produced during the Summer Space Program of the International Space University, held at Nasa-Ames Research Center (CA, USA) by 56 students from 15 countries. Chair of the team project was Rene Laufer. Facilitators were Alfonso Davila and Jhonny Zavaleta, and teacher associate supporting the team was Beatriz Gallardo. The human race has evolved, grown and expanded through the exploration of Earth. After initial steps on the Moon, our next challenge is to explore the solar system. Mars shows potential for both scientific discovery and future human settlement, and therefore represents a prime candidate for the next leap of human exploration. Such a bold endeavor will be a driver for an unprecedented worldwide cooperative effort and the catalyst for a new era of international, intercultural and interdisciplinary human relations. Scientific and technological progress will also accelerate as mankind is ushered into a new era of space exploration. Currently proposed Mars missions have identified a number of challenges such as high levels of radiation, harsh climate and limited launch windows. Recently discovered lava tubes on Mars present potential solutions to some of these issues, but raise a variety of intriguing new challenges. This paper reviews existing reference missions and identifies areas of further research essential for adapting mission architectures to utilize caves. Different mission scenarios are proposed and analyzed, with a number of different recommendations given. An analysis of the feasibility of using Martian lava tubes as habitation is given in another paper by the same authors at COSPAR 2010 F34 Technical Session. Literature suggests a low radiation environment within Martian caves, allowing for extended duration missions. The ACCESS Mars Team concludes that the use of lava tubes as human habitats will be more beneficial for human Mars exploration than currently proposed surface solutions.

  3. Flood lavas on Earth, Io and Mars

    USGS Publications Warehouse

    Keszthelyi, L.; Self, S.; Thordarson, T.

    2006-01-01

    Flood lavas are major geological features on all the major rocky planetary bodies. They provide important insight into the dynamics and chemistry of the interior of these bodies. On the Earth, they appear to be associated with major and mass extinction events. It is therefore not surprising that there has been significant research on flood lavas in recent years. Initial models suggested eruption durations of days and volumetric fluxes of order 107 m3 s-1 with flows moving as turbulent floods. However, our understanding of how lava flows can be emplaced under an insulating crust was revolutionized by the observations of actively inflating pahoehoe flows in Hawaii. These new ideas led to the hypothesis that flood lavas were emplaced over many years with eruption rates of the order of 104 m3 s-1. The field evidence indicates that flood lava flows in the Columbia River Basalts, Deccan Traps, Etendeka lavas, and the Kerguelen Plateau were emplaced as inflated pahoehoe sheet flows. This was reinforced by the observation of active lava flows of ??? 100 km length on Io being formed as tube-fed flow fed by moderate eruption rates (102-103 m3 s-1). More recently it has been found that some flood lavas are also emplaced in a more rapid manner. New high-resolution images from Mars revealed 'platy-ridged' flood lava flows, named after the large rafted plates and ridges formed by compression of the flow top. A search for appropriate terrestrial analogues found an excellent example in Iceland: the 1783-1784 Laki Flow Field. The brecciated Laki flow top consists of pieces of pahoehoe, not aa clinker, leading us to call this 'rubbly pahoehoe'. Similar flows have been found in the Columbia River Basalts and the Kerguelen Plateau. We hypothesize that these flows form with a thick, insulating, but mobile crust, which is disrupted when surges in the erupted flux are too large to maintain the normal pahoehoe mode of emplacement Flood lavas emplaced in this manner could have

  4. Does the Cave Environment Reduce Functional Diversity?

    PubMed Central

    Fernandes, Camile Sorbo; Batalha, Marco Antonio; Bichuette, Maria Elina

    2016-01-01

    Caves are not colonised by all taxa present in the surface species pool, due to absence of light and the tendency to food limitation when compared to surface communities. Under strong species sorting during colonisation and later by the restrictive environmental filter, traits that are not adaptive in subterranean habitats may be filtered out. We tested whether cave communities were assembled by the restrictive regime propitiated by permanent darkness or by competitive exclusion due to resource scarcity. When compared to surface communities, the restrictive subterranean regime would lead to lower functional diversity and phenotypic clustering inside the caves, and the opposite should be expected in the case of competitive exclusion. Using isopods (Oniscidea) as model taxa, we measured several niche descriptors of taxa from surface and cave habitats, used a multivariate measure of functional diversity, and compared their widths. We found phenotypic overdispersion and higher functional diversity in cave taxa when compared to surface taxa. On the one hand, the dry climate outside of caves hampered the survival of several taxa and their ecological strategies, not viable under severe desiccation risk, culminating in the clustering of functional traits. In contrast, this restriction does not occur inside of caves, where isopods find favourable conditions under lower predation pressures and more amenable environmental parameters that allow occupation and subsequent diversification. Our results showed that, at least for some taxa, caves may not be such a harsh environment as previously thought. The high functional diversity we found inside caves adds an additional reason for the conservation of these sensitive environments. PMID:27003837

  5. Mapping of Daedalia Planum Lava Field

    NASA Astrophysics Data System (ADS)

    Giacomini, Lorenza; Carli, Cristian; Massironi, Matteo; Pasquarè, Giorgio; Sgavetti, Maria

    2010-05-01

    Daedalia Planum is one of the Tharsis volcanic plains and is located southwest of the Arsia Mons. MOLA, THEMIS, MOC and OMEGA data have been analysed, providing a multi-scale characterisation of this Martian lava field. According to Mars Global Surveyor's MOLA data, the flanks of Arsia have an average slope <5°, while the surrounding regions, including Daedalia Planum, have slopes <0,5° and commonly <0,1°. Mars Odyssey/THEMIS VIS and IR images show a plain covered by a huge number of lava flows. Older and larger lava flows on the field have a length greater than ~1500 km. Moreover most of the Daedalia flows are associated to wrinkly and ropy surfaces, typical of pahoehoe lavas. On the base of the morphology differences among the flows and through stratigraphic relationships we performed a geological map of the area. MEX/OMEGA spectra were collected in different areas of the lava field. Besides the similar absorption bands OMEGA spectra showed also some differences in reflectance and spectral slope. The spectral map created using the SAM classification reveals that these spectral variations are generally in agreement with the lava flows mapped previously on the base of the flows morphology and stratigraphy. This suggested that such variability is related with different surface textures of the lava flow. Moreover in some cases spectral map highlighted the presence of spectral subunits inside the same stratigraphic unit, due likely to a different mineralogy or rock textures. Therefore spectral analysis revealed useful to improve the geological mapping of the Daedalia Planum region.

  6. Glacioclimatological study of perennial ice in the Fuji Ice Cave, Japan. Part 2. Interannual variation and relation to climate

    SciTech Connect

    Ohata, Tetsuo; Furukawa, Teruo; Osada, Kazuo )

    1994-08-01

    A glacioclimatological study of the interannual variation of mass of perennial ice in the Fuji Ice Cave at the foot of Mt. Fuji, in central Japan is presented. The cave is a 150-m-long lava tube located in a dense forest area at an altitude of 1120 m. It has a perennial floor ice of areas approximately 3000 m[sup 3] and mean thickness 2.8 m. Mean annual air temperature at the ground surface level is 8.4[degrees]C. Ice surface levels and air temperatures were measured 39 times from July 1984 to December 1992. Mean ice level showed a 15 cm increase from 1984 to 1989 and suddenly started to decrease from 1989 to 1992. In the increase stage, annual net balance (December to November) was similar at various points, but in the decreasing stage, the lowering of the level near the entrance was very large due to intense melting. Air temperature inside the cave at the end of the annual cycle showed a correlation to net balance of the corresponding year. Comparison of yearly net balance with meterological indices at ground level (winter and summer, annual mean air temperature and total precipitation; and number of days with strong precipitation) showed that net balance of a give year has a high correlation with the average winter air temperature anomaly of the preceding 4 yr. This is probably due to the high heat capacity of the cave system. 6 refs., 7 figs., 2 tabs.

  7. Bilateral Meckel's cave amyloidoma: a case report.

    PubMed

    Gültaşli, N; van den Hauwe, L; Bruneau, M; D'Haene, N; Delpierre, I; Balériaux, D

    2012-05-01

    Primary solitary amyloidoma of Meckel's cave is rare, and a bilateral location is even more rare. To the best of our knowledge, only 12 cases in the literature have described such a primary lesion, including one case of bilateral involvement of Meckel's cave. We report here on the case of a 57-year-old woman presenting with pseudotumor masses involving both Meckel's caves and responsible for trigeminal neuropathy. The final diagnosis of amyloidoma was made on the basis of histological examination of surgical biopsy specimens. PMID:21641646

  8. Organic Sulfur Gas Production in Sulfidic Caves

    NASA Astrophysics Data System (ADS)

    Stern, L. A.; Engel, A. S.; Bennett, P. C.

    2001-12-01

    Lower Kane Cave, Big Horn Basin, WY, permits access to an environment where anaerobic sulfide-rich groundwater meets the aerobic vadose zone. At this interface microorganisms thrive on diverse metabolic pathways including autotrophic sulfur oxidation, sulfate reduction, and aerobic heterotrophy. Springs introduce groundwater rich in H2S to the cave where it both degasses into the cave atmosphere and is used by chemautotrophic sulfur oxidizing bacteria in the cave spring and stream habitat. The cave atmosphere in the immediate vicinity of the springs has elevated levels of CO2, H2S and methane, mirroring the higher concentration of H2S and methane in the spring water. The high CO2 concentrations are attenuated toward the two main sources of fresh air, the cave entrance and breathing holes at the rear of the cave. Conventional toxic gas monitors permit estimations of H2S concentrations, but they have severe cross sensitivity with other reduced sulfur gases, and thus are inadequate for characterization of sulfur cave gases. However employment of a field-based GC revealed elevated concentrations of carbonyl sulfide in cave atmosphere. Cultures of microorganisms collected from the cave optimized for enriching fermenters and autotrophic and heterophic sulfate reducing bacteria each produced carbonyl sulfide suggesting a biogenic in origin of the COS in addition to H2S. Enrichment cultures also produced methanethiol (methyl mercaptan) and an additional as yet undetermined volatile organic sulfur compound. In culture, the organo-sulfur compounds were less abundant than H2S, whereas in the cave atmosphere the organo-sulfur compounds were the dominant sulfur gases. Thus, these organo-sulfur gases may prove to be important sources of both reduced sulfur and organic carbon to microorganisms living on the cave wall in a subaerial habitat. Moreover groundwater has not yet been recognized as a source of sulfur gases to the atmosphere, but with the abundance of sulfidic

  9. Nornahraun lava morphology and mode of emplacement

    NASA Astrophysics Data System (ADS)

    Pedersen, Gro B. M.; Höskuldsson, Armann; Riishuus, Morten S.; Jónsdóttir, Ingibjörg; Gudmundsson, Magnús T.; Sigmundsson, Freysteinn; Óskarsson, Birgir V.; Drouin, Vincent; Gallagher, Catherine; Askew, Rob; Moreland, William M.; Dürig, Tobias; Dumont, Stephanie; Þórdarson, Þór

    2015-04-01

    The ongoing Nornahraun eruption is the largest effusive eruption in Iceland since the Laki eruption in 1783-84, with an estimated lava volume of ~1.15 km3 covering an area of ~83.4 km2 (as of 5 JAN 2015). The eruption provides an unprecedented opportunity to study i) lava morphologies and their emplacement styles, ii) the transition from from open to closed lava pathways and iii) lava pond formation. Tracking of the lava advancement and morphology has been performed by GPS and GoPro cameras installed in 4×4 vehicles as well as video footage. Complimentary observations have been provided from aircraft platforms and by satellite data. Of particular importance for lava morphology observations are 1-12 m/pixel airborne SAR images (x-band). The Nornahraun flow field comprises a continuum of morphologies from pāhoehoe to 'a'ā, which have varied tem-porally and spatially. At the onset of the eruption 31 AUG, lava flows advanced rapidly (400-800 m/hr) from the 1.5 km long fissure as large slabby pāhoehoe [1-3] sheet lobes, 100-500 m wide and 0.3-1 m thick at the flow fronts. By 1 SEPT, the flows began channeling towards the NE constrained by the older Holuhraun I lava field and the to-pography of flood plain itself. A central open channel developed, feeding a 1-2 km wide active 'a'ā frontal lobe that advanced 1-2 km/day. In addition to its own caterpillar motion, the frontal lobe advanced in a series of 30-50 m long breakouts, predominantly slabby and rubbly pāhoehoe [4,5]. These breakouts had initial velocities of 10-30 m/hr and reached their full length within tens of minutes and subsequently inflated over hours. With the continuous advancement of the 'a'ā flow front, the breakouts were incorporated into the 'a'ā flow fronts and seldom preserved. At the margins of the frontal lava lobe, the breakouts were more sporadic, but predominantly rubbly pāhoehoe and slabby pāhoehoe, as at the flow front. The lava flow advanced ENE into Jökulsá á Fjöllum on 7 SEPT

  10. Studies of fluid instabilities in flows of lava and debris

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan H.

    1987-01-01

    At least two instabilities have been identified and utilized in lava flow studies: surface folding and gravity instability. Both lead to the development of regularly spaced structures on the surfaces of lava flows. The geometry of surface folds have been used to estimate the rheology of lava flows on other planets. One investigation's analysis assumed that lava flows have a temperature-dependent Newtonian rheology, and that the lava's viscosity decreased exponentially inward from the upper surface. The author reviews studies by other investigators on the analysis of surface folding, the analysis of Taylor instability in lava flows, and the effect of surface folding on debris flows.

  11. Nodal network generator for CAVE3

    NASA Technical Reports Server (NTRS)

    Palmieri, J. V.; Rathjen, K. A.

    1982-01-01

    A new extension of CAVE3 code was developed that automates the creation of a finite difference math model in digital form ready for input to the CAVE3 code. The new software, Nodal Network Generator, is broken into two segments. One segment generates the model geometry using a Tektronix Tablet Digitizer and the other generates the actual finite difference model and allows for graphic verification using Tektronix 4014 Graphic Scope. Use of the Nodal Network Generator is described.

  12. Fire, Lava Flows, and Human Evolution

    NASA Astrophysics Data System (ADS)

    Medler, M. J.

    2015-12-01

    Richard Wrangham and others argue that cooked food has been obligate for our ancestors since the time of Homo erectus. This hypothesis provides a particularly compelling explanation for the smaller mouths and teeth, shorter intestines, and larger brains that separate us from other hominins. However, natural ignitions are infrequent and it is unclear how earlier hominins may have adapted to cooked food and fire before they developed the necessary intelligence to make or control fire. To address this conundrum, we present cartographical evidence that the massive and long lasting lava flows in the African Rift could have provided our ancestors with episodic access to heat and fire as the front edges of these flows formed ephemeral pockets of heat and ignition and other geothermal features. For the last several million years major lava flows have been infilling the African Rift. After major eruptions there were likely more slowly advancing lava fronts creating small areas with very specific adaptive pressures and opportunities for small isolated groups of hominins. Some of these episodes of isolation may have extended for millennia allowing these groups of early hominins to develop the adaptations Wrangham links to fire and cooked food. To examine the potential veracity of this proposal, we developed a series of maps that overlay the locations of prominent hominin dig sites with contemporaneous lava flows. These maps indicate that many important developments in hominin evolution were occurring in rough spatial and temporal proximity to active lava flows. These maps indicate it is worth considering that over the last several million years small isolated populations of hominins may have experienced unique adaptive conditions while living near the front edges of these slowly advancing lava flows.

  13. Genomic sequencing of Pleistocene cave bears

    SciTech Connect

    Noonan, James P.; Hofreiter, Michael; Smith, Doug; Priest, JamesR.; Rohland, Nadin; Rabeder, Gernot; Krause, Johannes; Detter, J. Chris; Paabo, Svante; Rubin, Edward M.

    2005-04-01

    Despite the information content of genomic DNA, ancient DNA studies to date have largely been limited to amplification of mitochondrial DNA due to technical hurdles such as contamination and degradation of ancient DNAs. In this study, we describe two metagenomic libraries constructed using unamplified DNA extracted from the bones of two 40,000-year-old extinct cave bears. Analysis of {approx}1 Mb of sequence from each library showed that, despite significant microbial contamination, 5.8 percent and 1.1 percent of clones in the libraries contain cave bear inserts, yielding 26,861 bp of cave bear genome sequence. Alignment of this sequence to the dog genome, the closest sequenced genome to cave bear in terms of evolutionary distance, revealed roughly the expected ratio of cave bear exons, repeats and conserved noncoding sequences. Only 0.04 percent of all clones sequenced were derived from contamination with modern human DNA. Comparison of cave bear with orthologous sequences from several modern bear species revealed the evolutionary relationship of these lineages. Using the metagenomic approach described here, we have recovered substantial quantities of mammalian genomic sequence more than twice as old as any previously reported, establishing the feasibility of ancient DNA genomic sequencing programs.

  14. LAVA: lithography analysis using virtual access

    NASA Astrophysics Data System (ADS)

    Hsu, Chang; Yang, Rona; Cheng, Jeffery; Chien, Peter; Wen, Victor; Neureuther, Andrew R.

    1998-06-01

    A web site allowing remote operation of the SPLAT, SAMPLE, TEMPEST and SIMPL simulators has been developed to promote collaborative work on lithography and in particular on EUV technology. Based on the extensive use of platform independent programming languages, LAVA is accessible from all modern computing platforms. The software supporting the web site is available to others in creating similar web site sites and in making simulators such as those from other universities 'play' together. The web site explores new paradigms in remote operation of lithography simulators and introduces more application-oriented modes of interaction with technologists. The LAVA web site URL is http://cuervo.eecs.berkeley.edu/Volcano/

  15. Experimental Compaction of Pumiceous Dome Lavas

    NASA Astrophysics Data System (ADS)

    Kendrick, J.; Ashwell, P. A.; Lavalleé, Y.; Kennedy, B. M.; Hess, K. U.; Cole, J.; Dingwell, D. B.

    2012-04-01

    Lava dome stability is reliant on pore pressure, which varies according to the evolution of the permeable porous network. Here, we present experimental results of porosity and permeability evolution during compaction of aphiric (from Ngongotaha volcano) and crystal-bearing (from Tarawera volcano) pumiceous, rhyolitic lavas from Taupo Volcanic Zone, New Zealand. The Ngongotaha sample has 55 % porosity and is from the crystal-free dome carapace erupted ~200 ka following caldera collapse at Rotorua Caldera. Two sample sets from Tarawera are crystalline, pumiceous clasts from a dome-collapse generated block and ash flow at Okataina Caldera ~1314 AD, and contain 50 and 25 % pores. This study tests the validity of the 'permeable foam' model by comparing properties of the experimentally compacted pumice to denser material seen in the exposed cores of Tarawera and Ngongotaha. Cylindrical samples were deformed under conditions similar to lava dome settings, under a constant, low axial stress of 2.8 MPa at 800-900oC (above the measured calorimetric glass transition temperatures). Deformation ensued to a total axial strain of 60% and the porosity and permeability of the samples were measured at strain increments of 10 %. Samples display different resultant strains under the same applied stress and exhibit strain-hardening behaviour during compaction. The development of textures and microstructures is characterised using petrographic analysis and x-ray computed tomography. Porosity reduces steadily with increasing strain, but reaches a minimum of 20 % porosity at 40-50 % strain (irrespective of starting porosity or crystallinity), after which further strain is accommodated by barrelling of the sample. A rapid reduction in permeability along the primary axis occurs during the initial stage of compression and continues to decrease with increasing strain and densification of the lava. Permeability development differs between lava types due to the influence of crystallinity on the

  16. Toward a model for leveed lava flows

    NASA Technical Reports Server (NTRS)

    Baloga, Stephen

    1987-01-01

    Many lava flows have two distinct volumetric components during emplacement. First, there is a component actively flowing in accordance with Newtonian or other constitutive relations. Second, there may be an inactive, stationary component that is no longer participating in the forward movement of the flow. Such passive components may take the form of flow-confining levees, solidified lateral margins, overspilling, plating, small ponds and sidestreams, or a lava tube. To describe the conservation of flow volume for the active component, governing equations are given and discussed.

  17. Lava tube morphology on Etna and evidence for lava flow emplacement mechanisms

    NASA Astrophysics Data System (ADS)

    Calvari, Sonia; Pinkerton, Harry

    1999-06-01

    Lava tubes play a pivotal role in the formation of many lava flow fields. A detailed examination of several compound `a`a lava flow fields on Etna confirmed that a complex network of tubes forms at successively higher levels within the flow field, and that tubes generally advance by processes that include flow inflation and tube coalescence. Flow inflation is commonly followed by the formation of major, first-order ephemeral vents which, in turn, form an arterial tube network. Tube coalescence occurs when lava breaks through the roof or wall of an older lava tube; this can result in the unexpected appearance of vents several kilometers downstream. A close examination of underground features allowed us to distinguish between ephemeral vent formation and tube coalescence, both of which are responsible for abrupt changes in level or flow direction of lava within tubes on Etna. Ephemeral vent formation on the surface is frequently recorded underground by a marked increase in size of the tube immediately upstream of these vents. When the lining of an inflated tube has collapsed, `a`a clinker is commonly seen in the roof and walls of the tube, and this is used to infer that inflation has taken place in the distal part of an `a`a lava flow. Tube coalescence is recognised either from the compound shape of tube sections, or from breached levees, lava falls, inclined grooves or other structures on the walls and roof. Our observations confirm the importance of lava tubes in the evolution of extensive pahoehoe and `a`a flow fields on Etna.

  18. Geology of selected lava tubes in the Bend Area, Oregon

    NASA Technical Reports Server (NTRS)

    Greely, R.

    1971-01-01

    Longitudinal profiles representing 5872.5 m of mapped lava tubes and a photogeologic map relating lava tubes to surface geology, regional structure and topography are presented. Three sets of lava tubes were examined: (1) Arnold Lava Tube System (7km long) composed of collapsed and uncollapsed tube segments and lava ponds, (2) Horse Lava Tube System (11 km long) composed of parallel and anastomosing lava tube segments, and (3) miscellaneous lava tubes. Results of this study tend to confirm the layered lava hypothesis of Ollier and Brown (1965) for lava tube formation; however, there are probably several modes of formation for lava tubes in general. Arnold System is a single series of tubes apparently formed in a single basalt flow on a relatively steep gradient. The advancing flow in which the tubes formed was apparently temporarily halted, resulting in the formation of lava ponds which were inflated and later drained by the lava tube system. Horse System probably formed in multiple, interconnected flows. Pre-flow gradient appears to have been less than for Arnold System, and resulted in meandrous, multiple tube networks.

  19. 9. CRATER RIM DRIVE NEAR THURSTON LAVA TUBE. VIEW OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. CRATER RIM DRIVE NEAR THURSTON LAVA TUBE. VIEW OF CRENELATED LAVA STONE GUARD WALL AND ROCK CUT OPPOSITE. NOTE CATTLE GUARD ACROSS ROAD PARTIALLY PAVED OVER. - Crater Rim Drive, Volcano, Hawaii County, HI

  20. Quantitative constraints on the growth of submarine lava pillars from a monitoring instrument that was caught in a lava flow

    NASA Astrophysics Data System (ADS)

    Chadwick, William W.

    2003-11-01

    Lava pillars are hollow, vertical chimneys of solid basaltic lava that are common features within the collapsed interiors of submarine sheet flows on intermediate and fast spreading mid-ocean ridges. They are morphologically similar to lava trees that form on land when lava overruns forested areas, but the sides of lava pillars are covered with distinctive, evenly spaced, thin, horizontal lava crusts, referred to hereafter as "lava shelves." Lava stalactites up to 5 cm long on the undersides of these shelves are evidence that cavities filled with a hot vapor phase existed temporarily beneath each crust. During the submarine eruption of Axial Volcano in 1998 on the Juan de Fuca Ridge a monitoring instrument, called VSM2, became embedded in the upper crust of a lava flow that produced 3- to 5-m-high lava pillars. A pressure sensor in the instrument showed that the 1998 lobate sheet flow inflated 3.5 m and then drained out again in only 2.5 hours. These data provide the first quantitative constraints on the timescale of lava pillar formation and the rates of submarine lava flow inflation and drainback. They also allow comparisons to lava flow inflation rates observed on land, to theoretical models of crust formation on submarine lava, and to previous models of pillar formation. A new model is presented for the rhythmic formation of alternating lava crusts and vapor cavities to explain how stacks of lava shelves are formed on the sides of lava pillars during continuous lava drainback. Each vapor cavity is created between a stranded crust and the subsiding lava surface. A hot vapor phase forms within each cavity as seawater is syringed through tiny cracks in the stranded crust above. Eventually, the subsiding lava causes the crust above to fail, quenching the hot cavity and forming the next lava crust. During the 1998 eruption at Axial Volcano, this process repeated itself about every 2 min during the 81-min-long drainback phase of the eruption, based on the thickness

  1. Seismogenic lavas and explosive eruption forecasting.

    PubMed

    Lavallée, Y; Meredith, P G; Dingwell, D B; Hess, K-U; Wassermann, J; Cordonnier, B; Gerik, A; Kruhl, J H

    2008-05-22

    Volcanic dome-building episodes commonly exhibit acceleration in both effusive discharge rate and seismicity before explosive eruptions. This should enable the application of material failure forecasting methods to eruption forecasting. To date, such methods have been based exclusively on the seismicity of the country rock. It is clear, however, that the rheology and deformation rate of the lava ultimately dictate eruption style. The highly crystalline lavas involved in these eruptions are pseudoplastic fluids that exhibit a strong component of shear thinning as their deformation accelerates across the ductile to brittle transition. Thus, understanding the nature of the ductile-brittle transition in dome lavas may well hold the key to an accurate description of dome growth and stability. Here we present the results of rheological experiments with continuous microseismic monitoring, which reveal that dome lavas are seismogenic and that the character of the seismicity changes markedly across the ductile-brittle transition until complete brittle failure occurs at high strain rates. We conclude that magma seismicity, combined with failure forecasting methods, could potentially be applied successfully to dome-building eruptions for volcanic forecasting. PMID:18497822

  2. Valleys and Lava Flows near Olympus Mons

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The Mars Orbiter Camera (MOC) on board the Mars Global Surveyor (MGS) spacecraft has been documenting a variety of landforms in the volcanic Tharsis region, including these valleys and associated lava flows on the plains southeast of Olympus Mons. Lava flows are visible in the upper left quarter of this image, but meandering valleys with streamlined 'islands' dominate the scene. The valleys might have been carved by running water, but extremely fluid lava or mud might also have flowed through the channels. The exact role of each type of fluid--water, mud, or lava--remains to be determined. Illumination is from the right. The area shown is 7.3 km (4.5 mi) wide by 12 km (7.5 mi)long.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  3. Lava Flows in the Grand Canyon

    NASA Technical Reports Server (NTRS)

    2003-01-01

    Over vast expanses of time, natural processes like floods and volcanoes deposit layers of rock on the Earth's surface. To delve down through layers of rock is to explore our planet's history. Sometimes rock layers are exposed through human activity, such as drilling or excavation. Other times, rivers carve through the rock. One of the best, and most well-known, examples of a river exposing ancient rocks is Colorado River in Arizona's Grand Canyon. What fewer people know is that the Grand Canyon also has a history of relatively recent (on geologic time scales) volcanism. The evidence--hardened lava--spills down the canyon walls all the way to the river. On June 22, 2003, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured this image of the Grand Canyon, near 36.2 degrees north latitude and 113.2 degrees west longitude. ASTER detects light visible to human eyes as well as 'invisible' infrared light. Because different minerals reflect different portions of the light spectrum, ASTER can see varying mineral compositions of the rocks it observes, as well as detecting vegetation. In this three-dimensional visualization, lava fields appear brownish gray, darker than the layers of limestone, sandstone and other rock in the canyon. Vegetation appears green, and sparsely vegetated areas appear mustard. Water in the Colorado River is blue-purple. Geologists estimate that between 1.8 million and 400,000 years ago, lava flows actually dammed the Colorado River more than a dozen times. Some of the lava dams were as high as 600 meters (about 1,969 feet), forming immense reservoirs. Over time, enough water and sediment built up to push the river flow over the tops of these dams and eventually erode them away. Today, remnants of these lava dams remain throughout the area, along with the much older rock layers they cover. Among the most well known examples of these 'frozen' lava cascades is Lava Falls, which spills down to the

  4. Circulation patterns in active lava lakes

    NASA Astrophysics Data System (ADS)

    Redmond, T. C.; Lev, E.

    2014-12-01

    Active lava lakes provide a unique window into magmatic conduit processes. We investigated circulation patterns of 4 active lava lakes: Kilauea's Halemaumau crater, Mount Erebus, Erta Ale and Nyiragongo, and in an artificial "lava lake" constructed at the Syracuse University Lava Lab. We employed visual and thermal video recordings collected at these volcanoes and use computer vision techniques to extract time-dependent, two-dimensional surface velocity maps. The large amount of data available from Halemaumau enabled us to identify several characteristic circulation patterns. One such pattern is a rapid acceleration followed by rapid deceleration, often to a level lower than the pre-acceleration level, and then a slow recovery. Another pattern is periodic asymmetric peaks of gradual acceleration and rapid deceleration, or vice versa, previously explained by gas pistoning. Using spectral analysis, we find that the dominant period of circulation cycles at approximately 30 minutes, 3 times longer than the dominant period identified previously for Mount Erebus. Measuring a complete surface velocity field allowed us to map and follow locations of divergence and convergence, therefore upwelling and downwelling, thus connecting the surface flow with that at depth. At Nyiragongo, the location of main upwelling shifts gradually, yet is usually at the interior of the lake, for Erebus it is usually along the perimeter yet often there is catastrophic downwelling at the interior; For Halemaumau upwelling/downwelling position is almost always on the perimeter. In addition to velocity fields, we developed an automated tool for counting crustal plates at the surface of the lava lakes, and found a correlation, and a lag time, between changes if circulation vigor and the average size of crustal plates. Circulation in the artificial basaltic lava "lake" was limited by its size and degree of foaming, yet we measured surface velocities and identify patterns. Maximum surface velocity

  5. Identifying hazards associated with lava deltas

    NASA Astrophysics Data System (ADS)

    Poland, Michael P.; Orr, Tim R.

    2014-12-01

    Lava deltas, formed where lava enters the ocean and builds a shelf of new land extending from the coastline, represent a significant local hazard, especially on populated ocean island volcanoes. Such structures are unstable and prone to collapse—events that are often accompanied by small explosions that can deposit boulders and cobbles hundreds of meters inland. Explosions that coincide with collapses of the East Lae `Apuki lava delta at Kīlauea Volcano, Hawai`i, during 2005-2007 followed an evolutionary progression mirroring that of the delta itself. A collapse that occurred when the lava-ocean entry was active was associated with a blast of lithic blocks and dispersal of spatter and fine, glassy tephra. Shortly after delta growth ceased, a collapse exposed hot rock to cold ocean water, resulting in an explosion composed entirely of lithic blocks and lapilli. Further collapse of the delta after several months of inactivity, by which time it had cooled significantly, resulted in no recognizable explosion deposit. Seaward displacement and subsidence of the coastline immediately inland of the delta was measured by both satellite and ground-based sensors and occurred at rates of several centimeters per month even after the lava-ocean entry had ceased. The anomalous deformation ended only after complete collapse of the delta. Monitoring of ground deformation may therefore provide an indication of the potential for delta collapse, while the hazard associated with collapse can be inferred from the level of activity, or the time since the last activity, on the delta.

  6. Lava flows composition of the Daedalia Planum

    NASA Astrophysics Data System (ADS)

    Carli, Cristian; Giacomini, Lorenza; Sgavetti, Maria; Massironi, Matteo

    2010-05-01

    Daedalia Planum is a large lava plain, consisting of more than 1500 km lava flows emplaced over an almost flat terrain in the south-east area of Arsia Mons. The morphology of this region has been studied by Giacomini et al. (Planet.SpaceSci., 2009) and revealed the presence of various features indicative of inflation mechanisms. Thirteen morphologic units have been delineated and the stratigraphic relationships among these units have been established by the authors. Several compositional data indicate that most of the Mars surface appears to consist of tholeiitic basalts where rocks previously identified as andesite may be basaltic rocks coated with alteration rinds (McSween et al., Science, 2009). Some primitive alkaline olivine-rich basaltic rocks have been also recognized by rover exploration (McSween et al., J.Geophys.Res., 2006). The visible and near-infrared reflectance spectra contain electronic absorptions characteristic of mafic minerals including pyroxenes and olivine. These minerals, together with plagioclase, are the major components of lava's rocks. We have analyzed data acquired by the OMEGA orbiter spectrometer of the Mars Express mission. Several OMEGA's images have been studied collecting sets of spectra from each of the thirteen geological units. The spectra indicate a relatively uniform composition of the lavas, characterized by two wide absorption bands (I and II) at about 1000 and 2000 nm, respectively. These spectral features are diagnostic of the presence of pyroxenes, and the continuum removed spectra permit us to recognize the presence of two different pyroxenes . The precise minima positions of band I, between 950 and 1000 nm, and of band II, between 1800 and 2000 nm, suggest the presence in this region of low calcium and subcalcium clinopyroxene, like pigeonite and augite, with variable relative abundances. The presence of these types of pyroxenes suggests a tholeiitic composition of the Daedalia Planum long lava flows, in agreement with

  7. The hydrothermal alteration of cooling lava domes

    NASA Astrophysics Data System (ADS)

    Ball, Jessica L.; Stauffer, Philip H.; Calder, Eliza S.; Valentine, Greg A.

    2015-12-01

    Hydrothermal alteration is a recognized cause of volcanic instability and edifice collapse, including that of lava domes or dome complexes. Alteration by percolating fluids transforms primary minerals in dome lavas to weaker secondary products such as clay minerals; moreover, secondary mineral precipitation can affect the porosity and permeability of dome lithologies. The location and intensity of alteration in a dome depend heavily on fluid pathways and availability in conjunction with heat supply. Here we investigate postemplacement lava dome weakening by hydrothermal alteration using a finite element numerical model of water migration in simplified dome geometries. This is combined with the rock alteration index (RAI) to predict zones of alteration and secondary mineral precipitation. Our results show that alteration potential is highest at the interface between the hot core of a lava dome and its clastic talus carapace. The longest lived alteration potential fields occur in domes with persistent heat sources and permeabilities that allow sufficient infiltration of water for alteration processes, but not so much that domes cool quickly. This leads us to conclude that alteration-induced collapses are most likely to be shallow seated and originate in the talus or talus/core interface in domes which have a sustained supply of magmatic heat. Mineral precipitation at these zones of permeability contrast could create barriers to fluid flow, potentially causing gas pressurization which might promote deeper seated and larger volume collapses. This study contributes to our knowledge of how hydrothermal alteration can affect lava domes and provides constraints on potential sites for alteration-related collapses, which can be used to target hazard monitoring.

  8. The Tony Grove Karst Region in Northern Utah: From Cave Sediments to Fluvial Geomorphology

    NASA Astrophysics Data System (ADS)

    Smith, H. D.

    2013-12-01

    The Tony Grove lake area is a dolomitic karst region in the Bear River Range of the Middle Rocky Mountain Province (Hintze 1973, Wilson 1976). The 5 km study area (Figure 1) is strewn with boulders and consists of a combination of subsurface dissolution caves underlying the highly-eroded karst surface reminiscent of past glaciation. Traces of the dynamic mountain structure can be seen in faults, fractures, and folds with the largest being the Logan Syncline (Wilson, 1976) formed during the Sevier Orogeny. The Tony Grove area stratigraphy is dominated by the Ordovician (505 MYR) Fish Haven dolomite and Silurian (438 MYR) Laketown dolomite units topped with some Devonian (406 MYR) aged inter-bedded quartzite, shale, and dolostone from the Water Canyon Formation (Morgan 1992, Spangler 2001). The 5 km study area contains over 90 karst features formed through vadose water flow due to the alpine proximity. The development and exhumation of these features have been greatly influenced over time by plate tectonics and water. We investigate cave formation and sediments as an indicator of past water flow and watershed dynamics. Figure 1. Site location of the Tony Grove lake area including an image of the karst terrain and geologic map showing the Logan Peak Syncline. The area is home to about 90 karst features including both do lines and caves. Figure 2. The cave sediments in this image of Thundershower Cave in the Tony Grove lake area show the flow pattern and a step and pool channel morphology with a side channel formed to the right during times of higher flow.

  9. The Tony Grove Karst Region in Northern Utah: From Cave Sediments to Fluvial Geomorphology

    NASA Astrophysics Data System (ADS)

    Smith, H. D.

    2012-12-01

    The Tony Grove lake area is a dolomitic karst region in the Bear River Range of the Middle Rocky Mountain Province (Hintze, 1973; Wilson, 1976). Figure 1. The 5 km study area is strewn with boulders and consists of a combination of subsurface dissolution caves underlying the highly-eroded karst surface remnancent of past glaciation. Traces of the dynamic mountain structure can be seen in faults, fractures, and folds with the largest being the Logan Syncline (Wilson, 1976) formed during the Sevier Orogeny. The Tony Grove area stratigraphy is dominated by the Ordovician (505 MYR) Fish Haven dolomite and Silurian (438 MYR) Laketown dolomite units topped with some Devonian (406 MYR) aged inter-bedded quartzite, shale, and dolostone from the Water Canyon Formation (Morgan 1992, Spangler 2001). The 5 km study area contains over 90 karst features formed through vadose water flow due to the alpine proximity. The development and exhumation of these features have been greatly influenced over time by plate tectonics and water. We investigate cave formation and sediments as an indicator of past water flow and watershed dynamics (Figure 2). Figure 1. Site location of the Tony Grove Lake Area including an image of the karst terrain and geologic map showing the Logan Peak Syncline. The area is home to about 90 karst features inculding both dolines and caves. Figure 2. The cave sediments in this image of Thundershower Cave in the Tony Grove Lake Area show the flow pattern and a step and pool channel morphology with a side channel formed to the right during times of higher flow.

  10. The influence of cave stream sediments on the transport behavior of karst springs

    NASA Astrophysics Data System (ADS)

    Wagner, T.; Winkler, G.; Woessner, W.; Birk, S.

    2012-04-01

    Spring response to recharge in karst systems is influenced by the complex distribution of the rock mass hydraulic properties, fracture systems, and the presence of conduits. In addition the exchange of karst water with unconsolidated sediments in conduits may also further influence spring responses. To evaluate the effects of cave streams and sediments on solute transport in karst systems a small scale tracer experiment using fluorescein as an artificial tracer and water temperature as a natural tracer was conducted within the hyporheic zone of the active cave stream Schmelzbach. This interior stream drains parts of the Lurbach Karst System (Semriach-Peggau, Styria, Austria). The main goal of the experiment was to investigate if measurable cave stream hyporheic exchange (with the stream bottom sediments) occurs and the degree to which this process alters the transport of conservative tracers. One hundred meters downstream of the tracer injection point three cross sections of monitoring wells (9 in total along a distance of approximately 25 m) were constructed and fitted with two vertically isolated activated charcoal bags, 10 cm and 30 cm below the streambed surface. PVC monitoring wells were installed along the three cross sections using hand driven steel pipes as a temporary casing. In two of these wells temperature sensors were placed at different depths within the saturated bed sediment to investigate how post tracer test stream flood events impacted the timing and rate of stream water penetration into the bed sediments. The tracer breakthrough curve was measured with a fluorimeter located 100 m from the injection point. The results show a sharp peak and a modest tailing of the breakthrough. A one-dimensional advection dispersion model that accounts for mass transfer and storage of tracer in immobile fluid zones such as pools or sediments provides a good fit to the measured breakthrough curve. The model results suggest that immobile fluid zones amount to 40% of

  11. Cave air ventilation and CO 2 outgassing by radon-222 modeling: How fast do caves breathe?

    NASA Astrophysics Data System (ADS)

    Kowalczk, Andrew J.; Froelich, Philip N.

    2010-01-01

    In general, the rate and timing of calcite precipitation is in part affected by variations in cave air CO 2 concentrations. Knowledge of cave ventilation processes is required to quantify the effect variations in CO 2 concentrations have on speleothem deposition rates and thus paleoclimate records. In this study we use radon-222 ( 222Rn) as a proxy of ventilation to estimate CO 2 outgassing from the cave to the atmosphere, which can be used to infer relative speleothem deposition rates. Hollow Ridge Cave, a wild cave preserve in Marianna, Florida, is instrumented inside and out with multiple micro-meteorological sensor stations that record continuous physical and air chemistry time-series data. Our time series datasets indicate diurnal and seasonal variations in cave air 222Rn and CO 2 concentrations, punctuated by events that provide clues to ventilation and drip water degassing mechanisms. Average cave air 222Rn and CO 2 concentrations vary seasonally between winter ( 222Rn = 50 dpm L - 1 , where 1 dpm L - 1 = 60 Bq m - 3 ; CO 2 = 360 ppmv) and summer ( 222Rn = 1400 dpm L - 1 ; CO 2 = 3900 ppmv). Large amplitude diurnal variations are observed during late summer and autumn ( 222Rn = 6 to 581 dpm L - 1 ; CO 2 = 360 to 2500 ppmv). We employ a simple first-order 222Rn mass balance model to estimate cave air exchange rates with the outside atmosphere. Ventilation occurs via density driven flow and by winds across the entrances which create a 'venturi' effect. The most rapid ventilation occurs 25 m inside the cave near the entrance: 45 h - 1 (1.33 min turnover time). Farther inside (175 m) exchange is slower and maximum ventilation rates are 3 h - 1 (22 min turnover time). We estimate net CO 2 flux from the epikarst to the cave atmosphere using a CO 2 mass balance model tuned with the 222Rn model. Net CO 2 flux from the epikarst is highest in summer (72 mmol m - 2 day - 1 ) and lowest in late autumn and winter (12 mmol m - 2 day - 1 ). Modeled ventilation and net CO 2

  12. NASA Aircraft Aids Earth-Mars Cave Detection Study

    NASA Video Gallery

    The most likely location for discovering potential primitive life forms on Mars to be in caves. A recent NASA-funded airborne and ground study designed to aid in detection of caves on the Earth, th...

  13. Preservation of Microbial-Mineral Biosignatures in Caves

    NASA Astrophysics Data System (ADS)

    Boston, P. J.; Alexander, C.

    2016-05-01

    Earth caves are wonderful preservation environments for distinctive in situ biopatterns and biominerals. Several thousand volcanic caves have been detected on Mars and may contain biosignatures or extant life and are valuable future mission targets.

  14. PATTERNS OF ENDEMISM OF THE EASTERN NORTH AMERICAN CAVE FAUNA

    EPA Science Inventory

    Over 250 species of obligate terrestrial cave-dwelling animals (troglobionts) are known from single caves in the eastern United States. We investigate their geographic distribution, especially in relation to other troglobionts. We relate these patterns to taxonomic group, oppor...

  15. Some New Caves under Airport in Dubrovnik

    NASA Astrophysics Data System (ADS)

    Garasic, Mladen; Garasic, Davor

    2013-04-01

    Till today six speleological sites are known to exist at the premises of the Dubrovnik Airport in Croatia. This is a highly weathered area that has been in the focus of attention of speleologists ever since the airport was built in 1961/62. Two vertical caves measuring 31 m and 10.5 m in depth were discovered at that time. These two caves are now situated right underneath the new control tower of the Dubrovnik Airport. A tunnel entrance to the cave that has been known to local population for a long time is situated in the immediate vicinity of the control tower. In late 1950's the entrance to the cave was closed with concrete because of a military airport construction, but a tunnel was built so as to enable access to the cave. The cave is about 200 meters long and it fully occupies the space underneath the concrete runways of the Dubrovnik Airport. Thanks to efforts made by speleologists in 2006-2010 the cave was adapted to enable tourist visits, and it is now the world's only tourist cave underneath an operating airport. During apron extension activities in May 2012, three additional speleological sites were discovered and examined, together with other previously discovered caves, from the standpoint of geophysics, geology and speleology. Results of exploration shows that there are several faults zones in karstified limestones. The water flow in the caverns varies depending on climatic conditions on the ground surface. Water reaches the caverns via joints directly from the ground surface (to a lesser extent) or in deeper parts via joints and paraclases from other parts of Cretaceous carbonate formations (in most cases). The weathering zone depth in the area of these speleological features, are estimated at 300 to 500 meters (included under sea levels) , and the zone of vertical circulation varies from 50 to 150 m. It is followed by the zone of horizontal circulation in which the ground water is carried via Cretaceous limestones toward submarine springs in the

  16. Emplacement of a silicic lava dome through a crater glacier: Mount St Helens, 2004-06

    USGS Publications Warehouse

    Walder, J.S.; LaHusen, R.G.; Vallance, J.W.; Schilling, S.P.

    2007-01-01

    The process of lava-dome emplacement through a glacier was observed for the first time after Mount St Helens reawakened in September 2004. The glacier that had grown in the crater since the cataclysmic 1980 eruption was split in two by the new lava dome. The two parts of the glacier were successively squeezed against the crater wall. Photography, photogrammetry and geodetic measurements document glacier deformation of an extreme variety, with strain rates of extraordinary magnitude as compared to normal alpine glaciers. Unlike normal temperate glaciers, the crater glacier shows no evidence of either speed-up at the beginning of the ablation season or diurnal speed fluctuations during the ablation season. Thus there is evidently no slip of the glacier over its bed. The most reasonable explanation for this anomaly is that meltwater penetrating the glacier is captured by a thick layer of coarse rubble at the bed and then enters the volcano's groundwater system rather than flowing through a drainage network along the bed.

  17. Bellholes: Ceiling Cavities Eroded By Bats in Caves of the Neotropical Climates

    NASA Astrophysics Data System (ADS)

    Miller, T.

    2014-12-01

    Hundreds of thousands of symmetrical, vertical, bullet-shaped cavities known as bellholes are present in the ceilings of caves restricted to the tropical Americas. Most have circular diameters (rarely influenced by joints or bedding) of at least 30 cm, and may be several meters in height. They are often paired with bellbasins (shallow depressions located vertically beneath them that contain guano produced by bats). Members of the species Artibeus jamaicensis (Jamaican Fruit Bat) are almost exclusive users of these roosts. Brown streaks flowing down the sides of the bellholes and centimeters-thick rinds of the basins below are largely apatite minerals produced by the reaction of the host limestone with phosphoric acids in the guano.Many bellholes have developed in speleothem in the cave ceilings, disproving early theories that they are the result of solution by phreatic currents in flooded caves. A. jamaicensis roosts singly or in harem groups of 2-14 that commonly cluster in the bellholes and it is likely that these social habits of this species focus corrosion resulting from the transfer of feces to rock (producing altered rock then removed by claws) to create discretely-spaced upward-growing cavities. Fossil evidence from Jamaica supports an arrival there from the mainland in the past 12,000 years, suggesting bellholes and bellbasins are geologically recent features in the Caribbean islands. Their locations (not all cave passages have bellholes) can provide information on the hydrological history or microclimate of a cave, due to the absence of both bellholes and bats in some specific situations, e.g. where physical barriers exist such as sumps, small airspaces above streams or through rock collapses, or with increasing distance from an entrance.Smaller circular, increasingly-indented ceiling cavities demonstrate a sequence of bellhole development. Small (23 cm diameter, 9 cm high), circular, streaked cavities in a limestone drainage tunnel constructed in 1927 in

  18. Ice-Confined Basaltic Lava Flows: Review and Discussion

    NASA Astrophysics Data System (ADS)

    Skilling, I.; Edwards, B. R.

    2012-12-01

    Basaltic lavas that are interpreted as having been emplaced in subglacial or ice-confined subaerial settings are known from several localities in Iceland, British Columbia and Antarctica. At least four different types of observations have been used to date to identify emplacement of basaltic lavas in an ice-rich environment: i) gross flow morphology, ii) surface structures, iii) evidence for ice-confined water during emplacement, and iv) lava fracture patterns. Five types of ice-confined lava are identified: sheets, lobes, mounds, linear ridges and sinuous ridges. While the appearance of lavas is controlled by the same factors as in the submarine environment, such as the geometry and configuration of vents and lava tubes, flow rheology and rates, and underlying topography, the presence of ice can lead to distinct features that are specific to the ice-confined setting. Other types have very similar or identical equivalents in submarine environment, albeit with some oversteepening/ice contact surfaces. Ice-confined lavas can form as (1) subaerial or subaqueous lavas emplaced against ice open to the air, (2) subaqueous lavas emplaced into pre-existing sub-ice drainage networks, and (3) subaqueous lavas emplaced into ponded water beneath ice. Their surface structures reflect the relationship between rates of lava flow emplacement at the site of ice-water-lava contact, ice melting and water drainage. Variations in local lava flow rates could be due to lava cooling, constriction, inflation, tube development, ice melting, ice collapse, lava collapse, changes in eruption rate etc. Episodes of higher lava flow rate would favour direct ice contact and plastic compression against the ice, generating oversteepened and/or overthickened chilled margins, cavities in the lava formed by melting of enveloped ice blocks (cryolith cavities) and structures such as flattened pillows and lava clasts embedded into the glassy margins. Melting back of the confining ice generates space to

  19. Underwater observations of active lava flows from Kilauea volcano, Hawaii

    USGS Publications Warehouse

    Tribble, G.W.

    1991-01-01

    Underwater observation of active submarine lava flows from Kilauea volcano, Hawaii, in March-June 1989 revealed both pillow lava and highly channelized lava streams flowing down a steep and unconsolidated lava delta. The channelized streams were 0.7-1.5 m across and moved at rates of 1-3 m/s. The estimated flux of a stream was 0.7 m3/s. Jets of hydrothermal water and gas bubbles were associated with the volcanic activity. The rapidly moving channelized lava streams represent a previously undescribed aspect of submarine volcanism. -Author

  20. Detecting short period variations in lava flux

    NASA Astrophysics Data System (ADS)

    James, M. R.; Pinkerton, H.

    2009-04-01

    Although the underpinning processes that govern the flow of lava have been recognized for some time, modeling the evolution of lava flow fields remains problematic due to the difficulties in fully constraining inputs to flow models. One of the main parameters controlling the evolution of individual flows is effusion rate, and long period effusion rate changes, such as flow-waning prior to the cessation of an eruption, can now be routinely incorporated in simulations. However, effusion rates commonly vary over a wide range of timescales (from years to minutes) and, for short period changes, neither the cause nor the effects are well understood. Nevertheless, short period changes can result in inaccuracies in the input data for simulations and can be responsible for altering flow directions by either building or breaching flow levees. Hence, understanding the processes involved in such changes is important for flow modeling and, furthermore, could eventually provide insight into flow instabilities within the conduit or variability within degassing processes. Observations of short period (e.g. <1 hr) variations in lava flux have been made previously in the field but associated changes cannot be identified in effusion rate data because of the generally low sampling frequency of such data. During the last week of July 2008, trail cameras were used to obtain dense time series imagery of the active lava flow at Mount Etna, Sicily. The trail cameras were modified to capture timelapse imagery by adding an interval timer which triggered image capture every 10 minutes. During daylight, the cameras collected 5 M-pixel colour images and, during nighttime, they automatically switched to a 2 M-pixel camera which collected (uncalibrated) black and white infrared images. For the color images, haze, cloud and sunglare combined with the low contrast between the active lava and its surroundings, prevented useful analysis. However, the infrared images captured at night clearly

  1. 75 FR 4417 - Wind Cave National Park, Custer County, SD

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-27

    ... Wind Cave National Park, Custer County, SD AGENCY: National Park Service. ACTION: Notice of... Statement, Wind Cave National Park, Custer County, South Dakota. SUMMARY: Pursuant to Section 102(2)(C) of... Environmental Impact Statement (Plan), Wind Cave National Park, Custer County, South Dakota. On December 3,...

  2. 36 CFR 7.68 - Russell Cave National Monument.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Russell Cave National... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.68 Russell Cave National Monument. (a) Caves—(1) Closed Areas. Entering, exploring, or remaining within any cave area other than the...

  3. 36 CFR 7.36 - Mammoth Cave National Park.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Mammoth Cave National Park. 7... SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.36 Mammoth Cave National Park. (a) Fishing—(1... Creek Lake. Live minnows and worms may be used in all other waters. (ii) (b)(1) Cave entry. Except...

  4. 36 CFR 7.68 - Russell Cave National Monument.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Russell Cave National... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.68 Russell Cave National Monument. (a) Caves—(1) Closed Areas. Entering, exploring, or remaining within any cave area other than the...

  5. 36 CFR 7.36 - Mammoth Cave National Park.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Mammoth Cave National Park. 7... SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.36 Mammoth Cave National Park. (a) Fishing—(1... Creek Lake. Live minnows and worms may be used in all other waters. (ii) (b)(1) Cave entry. Except...

  6. 36 CFR 7.68 - Russell Cave National Monument.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Russell Cave National... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.68 Russell Cave National Monument. (a) Caves—(1) Closed Areas. Entering, exploring, or remaining within any cave area other than the...

  7. 36 CFR 7.68 - Russell Cave National Monument.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Russell Cave National... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.68 Russell Cave National Monument. (a) Caves—(1) Closed Areas. Entering, exploring, or remaining within any cave area other than the...

  8. 36 CFR 7.36 - Mammoth Cave National Park.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Mammoth Cave National Park. 7... SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.36 Mammoth Cave National Park. (a) Fishing—(1... Creek Lake. Live minnows and worms may be used in all other waters. (ii) (b)(1) Cave entry. Except...

  9. 36 CFR 7.68 - Russell Cave National Monument.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Russell Cave National... INTERIOR SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.68 Russell Cave National Monument. (a) Caves—(1) Closed Areas. Entering, exploring, or remaining within any cave area other than the...

  10. 36 CFR 7.36 - Mammoth Cave National Park.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Mammoth Cave National Park. 7... SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.36 Mammoth Cave National Park. (a) Fishing—(1... Creek Lake. Live minnows and worms may be used in all other waters. (ii) (b)(1) Cave entry. Except...

  11. 36 CFR 7.36 - Mammoth Cave National Park.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Mammoth Cave National Park. 7... SPECIAL REGULATIONS, AREAS OF THE NATIONAL PARK SYSTEM § 7.36 Mammoth Cave National Park. (a) Fishing—(1... Creek Lake. Live minnows and worms may be used in all other waters. (ii) (b)(1) Cave entry. Except...

  12. Parallel speciation in Astyanax cave fish (Teleostei) in Northern Mexico.

    PubMed

    Strecker, Ulrike; Hausdorf, Bernhard; Wilkens, Horst

    2012-01-01

    We investigated differentiation processes in the Neotropical fish Astyanax that represents a model system for examining adaptation to caves, including regressive evolution. In particular, we analyzed microsatellite and mitochondrial data of seven cave and seven surface populations from Mexico to test whether the evolution of the cave fish represents a case of parallel evolution. Our data revealed that Astyanax invaded northern Mexico across the Trans-Mexican Volcanic Belt at least three times and that populations of all three invasions adapted to subterranean habitats. Significant differentiation was found between the cave and surface populations. We did not observe gene flow between the strongly eye and pigment reduced old cave populations (Sabinos, Tinaja, Pachon) and the surface fish, even when syntopically occurring like in Yerbaniz cave. Little gene flow, if any, was found between cave populations, which are variable in eye and pigmentation (Micos, Chica, Caballo Moro caves), and surface fish. This suggests that the variability is due to their more recent origin rather than to hybridization. Finally, admixture of the young Chica cave fish population with nuclear markers from older cave fish demonstrates that gene flow between populations that independently colonized caves occurs. Thus, all criteria of parallel speciation are fulfilled. Moreover, the microsatellite data provide evidence that two co-occurring groups with small sunken eyes and externally visible eyes, respectively, differentiated within the partly lightened Caballo Moro karst window cave and might represent an example for incipient sympatric speciation. PMID:21963344

  13. Metabolically active Crenarchaeota in Altamira Cave.

    PubMed

    Gonzalez, Juan M; Portillo, M Carmen; Saiz-Jimenez, Cesareo

    2006-01-01

    Altamira Cave contains valuable paleolithic paintings dating back to 15,000 years. The conservation of these unique paintings is attracting increasing interest, and so, understanding microbial proliferation in Altamira Cave represents a prioritary objective. Here, we show for the first time that members of the Crenarchaeota were metabolically active components of developing microbial communities. RNA was extracted directly from the studied environment, and a number of 16S rRNA gene sequences belonging to the low-temperature Crenarchaeota were detected. Although low-temperature Crenarchaeota detected in a variety of ecosystems by using molecular techniques remain uncultured, this RNA-based study confirms an active participation of the Crenarchaeota in cave biogeochemical cycles. PMID:16292522

  14. Support of LAVA Integration and Testing

    NASA Technical Reports Server (NTRS)

    Jackson, Marcus Algernon

    2014-01-01

    The Lunar Advanced Volatile Analysis (LAVA) subsystem is a part of the Regolith and Environment Science & Oxygen and Lunar Volatile Analysis (RESOLVE) Payload that will fly to the lunar pole on the Resource Prospector Mission (RPM) in 2019. The purpose of the mission is to characterize the water on the surface and subsurface of the moon in various locations in order to map the distribution. This characterization of water will help to understand how feasible water is as a resource that can be used for drinking water, breathable air, and propellants in future missions. This paper describes the key support activities performed during a 10 week internship; specifically, troubleshooting the Near Infrared Spectrometer for the Surge Tank (NIRST) instrument count loss, contributing to a clamp to be used in the installation of Resistive Temperature Detectors (RTDs) to tubing, performing a failure analysis of the LAVA Fluid Subsystem (FSS), and finalizing trade studies for release.

  15. Voluminous submarine lava flows from Hawaiian volcanoes

    SciTech Connect

    Holcomb, R.T.; Moore, J.G.; Lipman, P.W.; Belderson, R.H.

    1988-05-01

    The GLORIA long-range sonar imaging system has revealed fields of large lava flows in the Hawaiian Trough east and south of Hawaii in water as deep as 5.5 km. Flows in the most extensive field (110 km long) have erupted from the deep submarine segment of Kilauea's east rift zone. Other flows have been erupted from Loihi and Mauna Loa. This discovery confirms a suspicion, long held from subaerial studies, that voluminous submarine flows are erupted from Hawaiian volcanoes, and it supports an inference that summit calderas repeatedly collapse and fill at intervals of centuries to millenia owing to voluminous eruptions. These extensive flows differ greatly in form from pillow lavas found previously along shallower segments of the rift zones; therefore, revision of concepts of volcano stratigraphy and structure may be required.

  16. Cooling of Kilauea Iki lava lake

    SciTech Connect

    Hills, R.G.

    1982-02-01

    In 1959 Kilauea Iki erupted leaving a 110 to 120 m lake of molten lava in its crater. The resulting lava lake has provided a unique opportunity to study the cooling dynamics of a molten body and its associated hydrothermal system. Field measurements taken at Kilauea Iki indicate that the hydrothermal system above the cooling magma body goes through several stages, some of which are well modeled analytically. Field measurements also indicate that during most of the solidification period of the lake, cooling from above is controlled by 2-phase convection while conduction dominates the cooling of the lake from below. A summary of the field work related to the study of the cooling dynamics of Kilauea Iki is presented. Quantitative and qualitative cooling models for the lake are discussed.

  17. Modeling steam pressure under martian lava flows

    USGS Publications Warehouse

    Dundas, Colin M.; Keszthelyi, Laszlo P.

    2013-01-01

    Rootless cones on Mars are a valuable indicator of past interactions between lava and water. However, the details of the lava–water interactions are not fully understood, limiting the ability to use these features to infer new information about past water on Mars. We have developed a model for the pressurization of a dry layer of porous regolith by melting and boiling ground ice in the shallow subsurface. This model builds on previous models of lava cooling and melting of subsurface ice. We find that for reasonable regolith properties and ice depths of decimeters, explosive pressures can be reached. However, the energy stored within such lags is insufficient to excavate thick flows unless they draw steam from a broader region than the local eruption site. These results indicate that lag pressurization can drive rootless cone formation under favorable circumstances, but in other instances molten fuel–coolant interactions are probably required. We use the model results to consider a range of scenarios for rootless cone formation in Athabasca Valles. Pressure buildup by melting and boiling ice under a desiccated lag is possible in some locations, consistent with the expected distribution of ice implanted from atmospheric water vapor. However, it is uncertain whether such ice has existed in the vicinity of Athabasca Valles in recent history. Plausible alternative sources include surface snow or an aqueous flood shortly before the emplacement of the lava flow.

  18. Atmospheric /sup 222/Rn in tourist caves of Slovenia, Yugoslavia

    SciTech Connect

    Kobal, I.; Smodis, B.; Burger, J.; Skofljanec, M.

    1987-04-01

    Radon-222 concentrations in the air of 12 tourist caves in Slovenia, Yugoslavia were measured. In almost all the caves concentrations are higher than in the outdoor air, with the highest concentration in the Tabor Cave at about 6000 Bq m-3. From the /sup 222/Rn concentrations obtained, the activity of /sup 222/Rn inhaled by a visitor breathing cave air was calculated, and the bronchial dose was estimated. The inhaled activity and the bronchial dose were highest in the Tabor Cave with values of 10 kBq and 540 microSv, respectively.

  19. Clinker formation in basaltic lava flows

    NASA Astrophysics Data System (ADS)

    van Wyk de Vrie, B.; Loock, S.; Henot, J.

    2007-12-01

    Basaltic lava flows are classified according their surface morphology. They can be either aa, displaying a rough clinkery surface or pahoehoe, displaying a smooth clinkerless surface. These two surface types differ also in their emplacement and rheology, and can be differentiated in a shear-strain rate vs. apparent viscosity diagram (Hon & al., 2003). To understand clinker formation, one way is to see how a pahoehoe lava converts to an aa through shear-viscosity changes. Two possibilities occur: 1) the viscosity can increase (e.g. by levee formation) and clinkers will be formed by torque on the flow edges, or 2) the shear-strain will increase (lava influx increasing, topographic obstacles, slope change) and clinker will be formed by crust-breakage. These two clinker formatting processes are called magmatic fragmentation. Clinker will be formed on the summit and to the edges of the flow and they will appear at the base of its according the caterpillar motion usually associated with flows. However, in the Chaîne des Puys (French), basal clinker appears without top clinker (i.e. a pahoehoe lava flow with basal clinker) and thus another explanation is needed to explain them. Clinker samples were collected in different emplacement contexts and different part of flows. The SEM analysis of these samples and comparisons with ash samples from the literature show classical magmatic fragmentation textures (stepped fractures, non- synchronic fractures) in three aa lava flows. However, in one pahoehoe flow there are typical phreatomagmatic textures (blocky shapes, adhering fine particles). There are also shearing structures, such as microfaults in an intermediate flow. Thus, there are at least three different ways to form clinker: 1) classically by fragmentation at the flow base and the edges; 2) by phreatomagmatism at the base flow; 3) by shearing at the flow base and the edges. Basal shearing structures include fault gauges and welded clasts, indicating possible shear

  20. Instrumenting caves to collect hydrologic and geochemical data: case study from James Cave, Virginia

    USGS Publications Warehouse

    Schreiber, Madeline E.; Schwartz, Benjamin F.; Orndorff, William; Doctor, Daniel H.; Eagle, Sarah D.; Gerst, Jonathan D.

    2015-01-01

    Karst aquifers are productive groundwater systems, supplying approximately 25 % of the world’s drinking water. Sustainable use of this critical water supply requires information about rates of recharge to karst aquifers. The overall goal of this project is to collect long-term, high-resolution hydrologic and geochemical datasets at James Cave, Virginia, to evaluate the quantity and quality of recharge to the karst system. To achieve this goal, the cave has been instrumented for continuous (10-min interval) measurement of the (1) temperature and rate of precipitation; (2) temperature, specific conductance, and rate of epikarst dripwater; (3) temperature of the cave air; and (4) temperature, conductivity, and discharge of the cave stream. Instrumentation has also been installed to collect both composite and grab samples of precipitation, soil water, the cave stream, and dripwater for geochemical analysis. This chapter provides detailed information about the instrumentation, data processing, and data management; shows examples of collected datasets; and discusses recommendations for other researchers interested in hydrologic and geochemical monitoring of cave systems. Results from the research, briefly described here and discussed in more detail in other publications, document a strong seasonality of the start of the recharge season, the extent of the recharge season, and the geochemistry of recharge.

  1. Is Radon Emission in Caves Causing Deletions in Satellite DNA Sequences of Cave-Dwelling Crickets?

    PubMed Central

    Allegrucci, Giuliana; Sbordoni, Valerio; Cesaroni, Donatella

    2015-01-01

    The most stable isotope of radon, 222Rn, represents the major source of natural radioactivity in confined environments such as mines, caves and houses. In this study, we explored the possible radon-related effects on the genome of Dolichopoda cave crickets (Orthoptera, Rhaphidophoridae) sampled in caves with different concentrations of radon. We analyzed specimens from ten populations belonging to two genetically closely related species, D. geniculata and D. laetitiae, and explored the possible association between the radioactivity dose and the level of genetic polymorphism in a specific family of satellite DNA (pDo500 satDNA). Radon concentration in the analyzed caves ranged from 221 to 26000 Bq/m3. Specimens coming from caves with the highest radon concentration showed also the highest variability estimates in both species, and the increased sequence heterogeneity at pDo500 satDNA level can be explained as an effect of the mutation pressure induced by radon in cave. We discovered a specific category of nuclear DNA, the highly repetitive satellite DNA, where the effects of the exposure at high levels of radon-related ionizing radiation are detectable, suggesting that the satDNA sequences might be a valuable tool to disclose harmful effects also in other organisms exposed to high levels of radon concentration. PMID:25822625

  2. Helium Isotopes and Noble Gas Abundances of Cave Dripping Water in Three Caves in East Asia

    NASA Astrophysics Data System (ADS)

    Chen, A. T.; Shen, C. C.; Tan, M.; Li, T.; Uemura, R.; Asami, R.

    2015-12-01

    Paleo-temperature recorded in nature archives is a critical parameter to understand climate change in the past. With advantages of unique inert chemical characteristics and sensitive solubilities with temperature, dissolved noble gases in speleothem inclusion water were recently proposed to retrieve terrestrial temperature history. In order to accurately apply this newly-developed speleothem noble gas temperature (NGT) as a reliable proxy, a fundamental issue about behaviors of noble gases in the karst should be first clarified. In this study, we measured noble gas contents in air and dripping water to evaluate any ratio deviation between noble gases. Cave dripping water samples was collected from three selected caves, Shihua Cave in northern China, Furong Cave in southwestern, and Gyukusen Cave in an island located in the western Pacific. For these caves are characterized by a thorough mixing and long-term storage of waters in a karst aquifer by the absence of seasonal oxygen isotope shifts. Ratios of dripping water noble gases are statistically insignificant from air data. Helium isotopic ratios in the dripping water samples match air value. The results indicate that elemental and isotopic signatures of noble gases from air can be frankly preserved in the epikarst and support the fidelity of NGT techniques.

  3. Using Lava Tube Skylights To Derive Lava Eruption Temperatures on Io

    NASA Astrophysics Data System (ADS)

    Davies, Ashley Gerard; Keszthelyi, Laszlo P.; McEwen, Alfred S.

    2015-11-01

    The eruption temperature of Io’s silicate lavas constrains Io’s interior state and composition [1]. We have examined the theoretical thermal emission from lava tube skylights above basaltic and ultramafic lava channels. Assuming that tube-fed lava flows are common on Io, skylights could also be common. Skylights present steady thermal emission on a scale of days to months. We find that the thermal emission from such a target, measured at multiple visible and NIR wavelengths, can provide a highly accurate diagnostic of eruption temperature. However, the small size of skylights means that close flybys of Io are necessary, requiring a dedicated Io mission [2]. Observations would ideally be at night or in eclipse. We have modelled the thermal emission spectrum for different skylight sizes, lava flow stream velocities, end-member lava compositions, and skylight radiation shape factors, determining the resulting flow surface cooling rates. We calculate the resulting thermal emission spectrum as a function of viewing geometry. From the resulting 0.7:0.9 μm ratios, we see a clear distinction between basaltic and ultramafic compositions for skylights smaller than 20 m across, even if sub-pixel. Our analysis will be further refined as accurate high-temperature short-wavelength emissivity values become available [3]. This work was performed at the Jet Propulsion Laboratory-California Institute of Technology, under contract to NASA. We thank the NASA OPR Program for support. References: [1] Keszthelyi et al. (2007) Icarus 192, 491-502 [2] McEwen et al. (2015) The Io Volcano Observer (IVO) LPSC-46 abstract 1627 [3] Ramsey and Harris (2015) IAVCEI-2015, Prague, Cz. Rep., abstract IUGG-3519.

  4. Magnetostratigraphy of cave sediments, Wyandotte Ridge, Crawford County, southern Indiana

    SciTech Connect

    Pease, P.P.; Gomez, B. . Dept. of Geography and Geology); Schmidt, V.A. . Dept. of Geology and Planetary Science)

    1992-01-01

    The field polarities of 42 sediment samples obtained from 21 sites in Wyandotte Cave, and five smaller satellite caves in Wyandotte Ridge, southern Indiana, have been determined and correlated with magnetostratigraphic data from Mammoth Cave, Kentucky. In Wyandotte Cave sediment samples obtained between 137 m and 162 m in elevation possessed a normal field polarity, while samples obtained between 168 m and 171 m exhibited a field reversal. The reversal was interpreted to represent the most recent polarity change, dating the sediment fill and the end of the active period of the upper level of Wyandotte Cave at ca 0.788 Ma. There is a temporal correlation between the active period of the upper level in Wyandotte Cave and the C-level in Mammoth Cave, which lies at a similar elevation. Such a correlation is most likely a consequence of the contemporaneous abandonment of passages in the two cave systems during the early Pleistocene reconstruction of the Ohio River system, which acts as the base level control in both caves. Samples from two caves near the top of Wyandotte Ridge, located between elevations of 236 m and 241 m, exhibited a normal polarity. These caves are located at a higher elevation than any of the sample sites in Mammoth Cave and their location suggests that the fill predates sediments from that system. It appears most likely that the fill in these caves is a minimum of ca 2.48 Ma. old and correlates with the residuum of the upper Mitchell Plain surface, not with the fill in the upper (A- or B-levels) in Mammoth Cave.

  5. The Crystals Cave in a test tube

    NASA Astrophysics Data System (ADS)

    Puig, C.; Romero, M. L.

    2012-04-01

    It's quite easy to understand formation of crystals in Nature by evaporation of the solutions that contain minerals, but many times we have realised that our pupils hardly understand that precipitation is a process mostly caused by changing parameters in a solution, like pH, temperature, etc. and not necessarily depending on evaporation. We propose a hands-on activity using the context of the Cave of the Crystals in Naica's mine, Mexico. The Crystals Cave is a wonderful place where giant crystals of selenite (gypsum) have grown feeding from a supersaturated anhydrite solution1. Miners discovered the cave filled with hot water, and drained it to explore the gallery. The cave is now a giant laboratory where scientists are looking for the keys to understand geological processes. Teaching sequence (for students 15 years old) is as follows: DISCOVERING A MARVELLOUS PLACE: We showed our pupils several images and a short video of the Cave of the Crystals and ask them about the process that may have caused the phenomenon. Whole-class discussion. PRESENTING A CHALLENGE TO OUR STUDENTS: "COULD WE CREATE A CRYSTALS CAVE IN A TEST TUBE?" EXPERIMENTING TO IMITATE NATURE: Students tried to grow crystals simulating the same conditions as those in Naica's mine. We have chosen KNO3, a salt more soluble than gypsum. We added 85 g of salt to 200 ml of water (solubility of KNO3 at 25°C is 36 g per 100 gr of water) and heated it until it is dissolved. Afterwards, we poured the solution into some test tubes and other recipients and let them cool at room temperature. And they got a beautiful crystals cave!! THINKING A LITTLE MORE: we asked pupils some questions to make them think about the process and to predict what would happen in different situations. For example: a) What would happen with crystals if we heated the tubes again? or b) What would happen if we took the remaining solution from the tubes and keep it in the fridge? PROVING A NEW HYPOTHESIS: Pupils collected the remaining

  6. Bed Bugs FAQs

    MedlinePlus

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Bed Bugs FAQs Recommend on Facebook Tweet Share Compartir On ... are bed bugs treated and prevented? What are bed bugs? Bed bugs ( Cimex lectularius ) are small, flat, parasitic ...

  7. Comparison of Natural Dams from Lava Flows and Landslides on the Owyhee River, Oregon

    NASA Astrophysics Data System (ADS)

    Ely, L. L.; Brossy, C. C.; Othus, S. M.; Orem, C.; Fenton, C.; House, P. K.; O'Connor, J. E.; Safran, E. B.

    2008-12-01

    Numerous large lava flows and mass movements have temporarily dammed the Owyhee River in southeastern Oregon at various temporal and spatial scales. These channel-encroaching events potentially play a significant role in creating and maintaining the geomorphic features of river canyons in uplifted volcanic terranes that compose a significant part of the western U.S. Abundant landslides and lava flows have the capacity to inhibit incision by altering channel slope, width, and bed character, and burying valley- bottom bedrock under exogenous material; or promote incision by generating cataclysmic floods through natural dam failures. The natural dams vary in their source, morphology, longevity and process of removal, which in turn affects the extent and duration of their impact on the river. The 3 most recent lava flows filled the channel 10-75 m deep and flowed up to 26 kilometers downvalley, creating long, low dams that were subject to gradual, rather than catastrophic, removal. In the last 125 ka, the Saddle Butte and West Crater lava dams created reservoirs into which 10-30 meters of silt and sand were deposited. The river overtopped the dams and in most reaches eventually cut a new channel through the adjacent, less resistant bedrock buttresses. Terraces at several elevations downstream and upstream of the West Crater dam indicate periods of episodic incision ranging from 0.28 to 1.7 mm/yr., based on 3He exposure ages on strath surfaces and boulder-rich fluvial deposits. In contrast to the lava dams, outburst flood deposits associated with landslide dams are common along the river. The mechanisms of failure are related to the geologic setting, and include rotational slump complexes, cantilevered blocks and block slides, and massive earthflows. Most large-scale mass movements occur in reaches where the Owyhee canyon incises through stacks of interbedded fluviolacustrine sediments capped with lava flows. The frequently observed association of landslides and flood

  8. Reply to the Comment on "Sandstone caves on Venezuelan tepuis: Return to pseudokarst?"

    NASA Astrophysics Data System (ADS)

    Aubrecht, R.; Lánczos, T.; Gregor, M.; Schlögl, J.; Šmída, B.; Liščák, P.; Brewer-Carías, Ch.; Vlček, L.

    2013-09-01

    In Aubrecht et al. (2011) we brought new data showing that the arenitic caves in the Venezuelan tepuis did not necessarily originate through quartz cement dissolution ('arenization') but the main portion of the caves originated because of poor lithification prior to erosion. An additional important process is lateritization which is responsible for at least 30% of the caves' volume. Sauro et al. (2012) in their comment support the 'arenization' theory (quartz cement dissolution) and provide several arguments against some points of our research. Their main objections and arguments relate to the following topics: 1) the validity of the arenization theory, 2) the origin and importance of the 'finger-flow' pillars, 3) the importance of the Schmidt hammer measurements and, 4) metamorphism of the Matauí Formation. In our reply we present further documentation that: The quartz cement dissolution theory of cave evolution was far less documented petrographically than the new theory presented by us. Although the presence of quartz dissolution is evident, there is no current evidence that it is widespread or that it plays a trigger role. Many of the presented examples of corrosion on quartz grains could have been caused by local alkalization. In addition, the hydrogeochemical data presented in the comment to support the 'arenization' theory do not in fact contradict our speleogenetic interpretations. 'Finger-flow' pillars are speleogenetic indicators and not speleogenetic factors. Their absence in some caves provides no evidence against our theory. Schmidt hammer measurements only objectivize the data on contrasting hardness in the Matauí Formation beds. They do not say anything about the origin of this difference. The arguments of Sauro et al. (2012) involve the metamorphic overprint of the Matauí Formation shown by the presence of pyrophyllite and quartz mobilizations. Because quartz mobilization also occurs in hypergenic conditions, it may be neglected as a metamorphic

  9. Impacts of cave air ventilation and in-cave prior calcite precipitation on Golgotha Cave dripwater chemistry, southwest Australia

    NASA Astrophysics Data System (ADS)

    Treble, Pauline C.; Fairchild, Ian J.; Griffiths, Alan; Baker, Andy; Meredith, Karina T.; Wood, Anne; McGuire, Elizabeth

    2015-11-01

    Speleothem trace element chemistry is an important component of multi-proxy records of environmental change but a thorough understanding of hydrochemical processes is essential for its interpretation. We present a dripwater chemistry dataset (PCO2, alkalinity, Ca, SIcc, Mg and Sr) from an eight-year monitoring study from Golgotha Cave, building on a previous study of hydrology and dripwater oxygen isotopes (Treble et al., 2013). Golgotha Cave is developed in Quaternary aeolianite and located in a forested catchment in the Mediterranean-type climate of southwest Western Australia. All dripwaters from each of the five monitored sites become supersaturated with respect to calcite during most of the year when cave ventilation lowers PCO2 in cave air. In this winter ventilation mode, prior calcite precipitation (PCP) signals of increased Mg/Ca and Sr/Ca in dripwater are attributed to stalactite deposition. A fast-dripping site displays less-evolved carbonate chemistry, implying minimal stalactite growth, phenomena which are attributed to minimal degassing because of the short drip interval (30 s). We employ hydrochemical mass-balance modelling techniques to quantitatively investigate the impact of PCP and CO2 degassing on our dripwater. Initially, we reverse-modelled dripwater solutions to demonstrate that PCP is dominating the dripwater chemistry at our low-flow site and predict that PCP becomes enhanced in underlying stalagmites. Secondly, we forward-modelled the ranges of solution Mg/Ca variation that potentially can be caused by degassing and calcite precipitation to serve as a guide to interpreting the resulting stalagmite chemistry. We predict that stalagmite trace element data from our high-flow sites will reflect trends in original dripwater solutes, preserving information on biogeochemical fluxes within our system. By contrast, stalagmites from our low-flow sites will be dominated by PCP effects driven by cave ventilation. Our poorly karstified system allows us

  10. Intraformational deformation in the tuffs and lavas of Calico Hills exposed near Yucca Mountain, Nevada

    SciTech Connect

    Buesch, D.C. ); Dickerson, R.P. )

    1993-04-01

    The 12.9 Ma tuffs and lavas of Calico Hills (CH) records development of part of the Southwest Nevada Volcanic Field that formed during intermittent periods of extensional tectonism. Exposures of the CH in upper Paintbrush Canyon, 6 km northeast of Yucca Mountain, consists of five lava flows interstratified with pyroclastic flow and fallout deposits, and fluvially redeposited sediment. The lower part of the exposures (shown in cross section below) consists of a lava flow (L1), interbedded primary and redeposited tuffaceous deposits (R1a and R1b), massive breccia deposit (M1), lava flow (L2), massive breccia deposit (M2), and redeposited tuffaceous deposits (R2). Moderately developed stratification at the base of massive breccia deposit M1 and localized concentrations of lithic fragments throughout the deposit indicates probably deposition from a pyroclastic flow. Bedding in R1, R2, and the base of M1 (dashed line) parallels stratigraphic unit contacts. An intraformational unconformity between R1 subunits (solid line) is interpreted as a fluctuation in local base level, or minor folding prior to deposition of R1b. Northward thinning of post-R1 rocks indicate L1 and R1 were folded into a southeast plunging anticline that formed a topographic high; across which M1 was deposited and against which L2, M2, and R2 abutted. Because post-R2 CH deposits shown no significant intraformational deformation at this location, most deformation described here occurred early in the depositional history of the CH and resulted from localized compression synchronous with regional extension or localized tumescence associated with volcanism.

  11. Sampling Elysium lavas (13 deg N, 203 deg W)

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.

    1994-01-01

    The proposed Pathfinder landing site presents the opportunity to determine chemical and mineralogical compositions of an Elysium lava flow. The flow is part of a geologic unit of planetary significance. The proposed site appears suitable for landing, and lava surfaces should be accessible to the Pathfinder instruments. By analogy to terrestrial flood basalts, any lava analyzed by Pathfinder is likely to be representative of the entire Elysium province.

  12. Delineating recharge areas for Onondaga and Cathedral Caves using groundwater tracing techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Onondaga Cave and Cathedral Cave are two large, significant cave systems with active streams located along the Meramec River in the Ozarks ecoregion of Missouri. Groundwater dye tracing has delineated recharge areas for both caves in order to aid in the management of the cave systems by Onondaga Cav...

  13. Gusev Rocks Solidified from Lava (False Color)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin.

    Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy.

    The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks.

    As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography

  14. Gusev Rocks Solidified from Lava (3-D)

    NASA Technical Reports Server (NTRS)

    2006-01-01

    In recent weeks, as NASA's Mars Exploration Rover Spirit has driven through the basin south of 'Husband Hill,' it has been traversing mainly sand and dune deposits. This week, though, Spirit has been maneuvering along the edge of an arc-shaped feature called 'Lorre Ridge' and has encountered some spectacular examples of basaltic rocks with striking textures. This panoramic camera (Pancam) image shows a group of boulders informally named 'FuYi.' These basaltic rocks were formed by volcanic processes and may be a primary constituent of Lorre Ridge and other interesting landforms in the basin.

    Spirit first encountered basalts at its landing site two years ago, on a vast plain covered with solidified lava that appeared to have flowed across Gusev Crater. Later, basaltic rocks became rare as Spirit climbed Husband Hill. The basaltic rocks that Spirit is now seeing are interesting because they exhibit many small holes or vesicles, similar to some kinds of volcanic rocks on Earth. Vesicular rocks form when gas bubbles are trapped in lava flows and the rock solidifies around the bubbles. When the gas escapes, it leaves holes in the rock. The quantity of gas bubbles in rocks on Husband Hill varies considerably; some rocks have none and some, such as several here at FuYi, are downright frothy.

    The change in textures and the location of the basalts may be signs that Spirit is driving along the edge of a lava flow. This lava may be the same as the basalt blanketing the plains of Spirit's landing site, or it may be different. The large size and frothy nature of the boulders around Lorre Ridge might indicate that eruptions once took place at the edge of the lava flow, where the lava interacted with the rocks of the basin floor. Scientists hope to learn more as Spirit continues to investigate these rocks.

    As Earth approaches the Chinese New Year (The Year of the Dog), the Athena science team decided to use nicknames representing Chinese culture and geography

  15. The transport of CO2 into central Texas caves (Invited)

    NASA Astrophysics Data System (ADS)

    Breecker, D.; Banner, J. L.; Larson, T.

    2013-12-01

    It is well established that CO2 is flushed out of caves by seasonal or synoptic temperature- and barometric pressure-driven ventilation. The mechanism by which CO2 is transported into caves is not as well studied and must be understood in order to quantify carbon (C) cycling through caves, soils and epikarst. Transport mechanisms into caves include gas and aqueous phase (i.e. drip-water) transport. We interpret δ13C values of cave-air CO2 and O2/Ar ratios of cave-air in order to distinguish between these transport mechanisms in three central Texas caves. Gas phase transport might allow cave-air to be used as a simple proxy for otherwise largely inaccessible epikarst air. Drip-water transport might allow measurements of individual drips to be scaled up to cave-integrated assessment of water flux, calcite precipitation, and degassing-related isotope fractionation using measurements of cave-air CO2. We start by assuming gas phase transport and then evaluate the consistency of the results. We apply to cave-air CO2 the theory for steady state soil CO2 transport, which involves mixing with atmospheric air and isotope fractionation by diffusion. This allows calculation of the C isotope composition of the reduced C source for cave-air CO2 (δ13Cr). Calculated cave-air δ13Cr values are consistent with observed soil δ13Cr values. For instance, where trees are evenly distributed at the surface, cave-air δ13Cr values (-24‰) remained within 1‰ of tree-dominated soil δ13Cr values and were 3.5 to 4.5 ‰ lower than grass-dominated soil δ13Cr values, suggesting that trees are the dominant C source. This internally consistent explanation suggests that CO2 diffuses and/or advects into these caves as a gas because aqueous transport into caves would likely result in different cave-air and soil δ13Cr values, as described next. The magnitude of the CO2(g) -HCO3-(aq) carbon isotope per mil fractionation factor is -8.4 ‰ at 20.5°C, the mean Inner Space Cavern drip

  16. Identifying hazards associated with lava deltas

    USGS Publications Warehouse

    Poland, Michael P.; Orr, Tim R.

    2014-01-01

    Lava deltas, formed where lava enters the ocean and builds a shelf of new land extending from the coastline, represent a significant local hazard, especially on populated ocean island volcanoes. Such structures are unstable and prone to collapse—events that are often accompanied by small explosions that can deposit boulders and cobbles hundreds of meters inland. Explosions that coincide with collapses of the East Lae ‘Apuki lava delta at Kīlauea Volcano, Hawai‘i, during 2005–2007 followed an evolutionary progression mirroring that of the delta itself. A collapse that occurred when the lava–ocean entry was active was associated with a blast of lithic blocks and dispersal of spatter and fine, glassy tephra. Shortly after delta growth ceased, a collapse exposed hot rock to cold ocean water, resulting in an explosion composed entirely of lithic blocks and lapilli. Further collapse of the delta after several months of inactivity, by which time it had cooled significantly, resulted in no recognizable explosion deposit. Seaward displacement and subsidence of the coastline immediately inland of the delta was measured by both satellite and ground-based sensors and occurred at rates of several centimeters per month even after the lava–ocean entry had ceased. The anomalous deformation ended only after complete collapse of the delta. Monitoring of ground deformation may therefore provide an indication of the potential for delta collapse, while the hazard associated with collapse can be inferred from the level of activity, or the time since the last activity, on the delta.

  17. Terrestrial Photogrammetry of Active Lava Flows

    NASA Astrophysics Data System (ADS)

    James, M.; Robson, S.

    2006-12-01

    In order to improve our understanding of how lavas flow, cool and stop, accurate and frequent DEMs and associated temperature measurements of active flows are required. We describe the use of terrestrial photogrammetric techniques which allow detailed measurements to be carried out rapidly, frequently and over relevant spatial scales. Furthermore, the equipment required is sufficiently small and light to be easily deployed in remote areas. Images of lava flows from Etna (Sicily) and Hawai'i have been acquired, representing cases involving different length scales, observation distances and advance rates. On Etna, flow-front regions and distal channels of aa flows were studied over distances of up to 400 m. Advance rates were relatively slow (< 4 m hr-1) over flow-fronts ~7 m in height and up to ~30 m in width. The slow rate of change allowed topographic surfaces to be constructed from images collected from multiple locations using a single camera. Sequential surfaces were uses to monitor variations in the volumetric flux at the flow fronts. On Hawai'i, smaller spatial scales were required (distances <30 m) to cover the advance and subsequent inflation of pahoehoe toes. In contrast to the Etna case, the higher rate of lava advance precluded the use of one roving camera to provide topographic data. Hence, DEMs were generated from image pairs acquired using two synchronised and tripod-mounted cameras. Image pairs were collected every minute and the resulting topography can be used to rectify simultaneously collected thermal data. The different problems associated with data collection and processing in these two cases are discussed. This includes image matching issues and factors resulting from the differences between the rubbly aa and the relatively smooth pahoehoe surfaces.

  18. Geochemical Stratigraphy of Southern Parana' Lava Piles

    NASA Astrophysics Data System (ADS)

    Marzoli, A.; De Min, A.; Marques, L. S.; Nardy, A.; Chiaradia, M.

    2015-12-01

    Basaltic lava flows of the Paranà Large Igneous Province exhibit significant regional and stratigraphic geochemical variations. While the most notable difference concerns the dominance of low-Ti (TiO2 < 2.0 wt.%) and high-Ti types in the southern and northern part of the province, respectively, detailed analyses of lava flow sequences sampled mostly in drill cores allowed definition of six main groups of chemically distinct flow units. The chemical and possible age differences among these units were then used to define the global time-related evolution of Paranà basaltic magmatism and involvement of distinct mantle-source components. Newly sampled outcropping lava flow sequences from the southern Paranà do however only partially support this picture. Our new major and trace element and Sr-Nd-Pb isotopic data show that high- and low-Ti basaltic flows are interlayered. In particular, Pitanga type high-Ti basalts are interlayered with Gramado and Esmeralda low-Ti basalts (these latter being present both towards the base and the top of the sequence) in Paranà State, while in Santa Caterina State Gramado flows are interlayered with Urubici-type high-Ti basalts. The interlayering of distinct basaltic magma type requires near-synchronous eruption of chemically strongly different magma types generated from clearly heterogeneous mantle sources and erupted through separated magma plumbing systems, without apparent interaction (mixing) among the distinct basalts. In conclusion, the relative timing of low- and high-Ti magma types seems to be much more complicated than previously thought, as for example Esmeralda or Pitanga basalts, previously considered as quite late and postdating Gramado basalts, are indeed synchronous with them.

  19. Chips Off an Old Lava Flow

    NASA Astrophysics Data System (ADS)

    Taylor, G. J.

    2007-12-01

    Photogeologic and remote sensing studies of the Moon show that many light-colored, smooth areas in the highlands contain craters surrounded by dark piles of excavated debris. The dark deposits resemble the dark basalts that make up the lunar maria. They contain the same diagnostic minerals (especially high-calcium pyroxene) and chemical compositions (high iron oxide) as do mare basalts. The deposits formed when vast amounts of material ejected during the formation of giant impact basins covered pre-existing lava plains. Since the smooth plains are older than the youngest impact basin (about 3.8 billion years old), the lavas must have erupted before formation of the visible maria. In fact, they were visible maria for a while eons ago, but were buried by ejecta when the basins formed. We have samples of these ancient mare basalts. They reside in breccias collected from the lunar highlands. Age dating indicates that the chips have ages of 3.9 billion years and older. The oldest dated mare basalt in the Apollo collection is 4.23 billion years. Now Kentaro Terada (Hiroshima University, Japan), Mahesh Anand (Open University, UK), Anna Sokol and Addi Bischoff (Institute for Planetology, Muenster, Germany), and Yuji Sano (The University of Tokyo, Japan) have determined the age of pieces of an ancient lava flow in a lunar meteorite, Kalahari 009, found in Botswana in 1999. The team dated this very low-titanium mare basalt by using an ion microprobe to measure the isotopic composition of lead and uranium in phosphate minerals. They found that the basalt fragments in the rock have an age of about 4.35 (plus or minus 0.15) billion years. This overlaps with the ages of chemically-distinct igneous rocks from the highlands, indicating that diverse magmas were being produced early in the history of the Moon.

  20. Lava tubes - Potential shelters for habitats. [on moon

    NASA Technical Reports Server (NTRS)

    Horz, F.

    1985-01-01

    Natural caverns occur on the moon in the form of 'lava tubes', which are the drained conduits of underground lava rivers. The inside dimensions of these tubes measure tens to hundreds of meters, and their roofs are expected to be thicker than 10 meters. Consequently, lava tube interiors offer an environment that is naturally protected from the hazards of radiation and meteorite impact. Further, constant, relatively benign temperatures of -20 C prevail. These are extremely favorable environmental conditions for human activities and industrial operations. Significant operational, technological, and economical benefits might result if a lunar base were constructed inside a lava tube.

  1. Book Review: Caves and Karst of the Yorkshire Dales

    NASA Astrophysics Data System (ADS)

    Westaway, Rob

    2015-10-01

    The British Cave Research Association (BCRA) is the research division of the British Caving Association (BCA), itself the principal society in Britain for those interested in caving, with activities including provision of training and safety certification for cavers and managing access to caves. Although some UK cave-related research is carried out by academics, this tends to be restricted to archaeological investigations of caves that have served as human habitations, and to be focused more on the occupants than the caves themselves. In contrast, most cave exploration is undertaken as a leisure activity, under the auspices of clubs affiliated to the BCA/BCRA, this being indeed virtually the only field of Earth science where amateur investigators can continue to make significant discoveries. Many cave explorers are also affiliated with academic researchers, such as managers of dating laboratories; the synergy between these two groups is highly productive, having resulted for instance in the discovery and exploration in recent years of the vast Ogof Draenen cave system in South Wales, which probably dates back to the Early Pleistocene (e.g., Farrant et al., 2014).

  2. Exploring caves: teaching packet for grades K-3

    USGS Publications Warehouse

    U.S. Geological Survey

    1998-01-01

    "Exploring Caves" is an interdisciplinary set of materials on caves for grades K-3. Caves entail at least five scientific disciplines: earth science, hydrology, mapping, biology, and anthropology. Each of these disciplines involves a unique content area as well as the development of particular intellectual skills. This unit aims at helping teachers to sort and organize the most important ideas in this rich scientific area. Detailed lesson plans serve as ways to pass these ideas on to very young students. Most American caves are big holes that form in limestone rock. The holes begin as cracks in limestone. The cracks get bigger and bigger. They grow into underground streams, rivers, and even lakes. When water drains away, the waterways turn into open cave tunnels, passages, and caverns. It takes 10,000 to 100,000 years to form a cave big enough for people to move around inside. Water drips constantly in caves. The drips dissolve limestone minerals in one part of the cave. As water dries out, the minerals build up in other places. In this way, beautiful cave rock formations and crystals grow over thousands of years. These rock formations change dark limestone caves into hidden fantasy lands.

  3. Next generation phylogeography of cave and surface Astyanax mexicanus.

    PubMed

    Coghill, Lyndon M; Darrin Hulsey, C; Chaves-Campos, Johel; García de Leon, Francisco J; Johnson, Steven G

    2014-10-01

    The loss of traits is a commonly observed evolutionary pattern in cave organisms, but due to extensive morphological convergence, inferring relationships between cave and surface populations can be difficult. For instance, Astyanax mexicanus (the blind Mexican cavefish) is thought to have repeatedly lost its eyes following colonization of cave environments, but the number of evolutionarily independent invasions of this species into caves remains unclear. Because of these repeated losses, it has become a model organism for studying the genetic basis of phenotypic trait loss. Here we reconstruct a high-resolution phylogeography for A. mexicanus inferred from both mitochondrial DNA and several thousand single nucleotide polymorphisms. We provide novel insight into the origin of cave populations from the Sabinos and Río Subterráneo caves and present evidence that the Sabinos cave population is part of a unique cave lineage unrelated to other A. mexicanus cave populations. Our results indicate A. mexicanus cave populations have at least four independent origins. PMID:25014568

  4. Determining the Compositions of Extraterrestrial Lava Flows

    NASA Technical Reports Server (NTRS)

    Fink, Jonathan H.

    2002-01-01

    The primary purpose of this research project has been to develop techniques that allow the emplacement conditions of volcanic landforms on other planets to be related to attributes that can be remotely detected with available instrumentation. The underlying assumption of our work is that the appearance of a volcano, lava flow, debris avalanche, or exhumed magmatic intrusion can provide clues about the conditions operating when that feature was first emplaced. Magma composition, amount of crustal heat flow, state of tectonic stress, and climatic conditions are among the important variables that can be inferred from the morphology and texture of an igneous body.

  5. Stratigraphy and geochronology of pitfall accumulations in caves and fissures, Bermuda

    NASA Astrophysics Data System (ADS)

    Hearty, Paul J.; Olson, Storrs L.; Kaufman, Darrell S.; Edwards, R. Lawrence; Cheng, Hai

    2004-05-01

    Deep fractures ("fissures") and avens ("skylights") in limestone cave roofs create natural traps for sediments and biota. Fissures fill quickly with surface sediment and organisms soon after opening. Debris cones are formed as materials fall, wash, or drift on air through openings in cave skylights. Such deposits in Admiral's and Grand Canyon Cave, Bermuda contain distinct beds and are composed of mixtures of sediment and charcoal, together with fossils of land snails, crabs, birds, reptiles, and bats. The "pitfall" accumulations were periodically sealed over by calcite flowstone. A stratigraphic record of surface activity and fauna through both glacial and interglacial periods has been preserved. The succession also provides an ideal setting in which to compare several geochronological methods. Calibrated 14C ages on charcoal and shells provide dated horizons at 1600, 12,800, and about 35,000 14C yr BP. Thermal ionization mass spectrometric (TIMS) ages on several flowstone layers constrain the entire sequence in the Admiral's Cave sequence between 126,300±900 yr (Termination II) and historical times. A continuous relative-age record generated by amino acid epimerization (AAE) geochronology ( D-alloisoleucine/ L-isoleucine or aIle/Ile) on the pulmonate land gastropod Poecilozonites verifies the biostratigraphy, reveals a minimal degree of mixing between stratigraphic units, and establishes an independent temporal link between the subterranean and subaerial deposits of Bermuda. This convergence between stratigraphy and geochronology yields a precisely dated succession from the oceanic island of Bermuda, and thus presents a unique opportunity to assess the rates and processes of evolutionary and climate change during that interval.

  6. Actinobacterial Diversity in Volcanic Caves and Associated Geomicrobiological Interactions.

    PubMed

    Riquelme, Cristina; Marshall Hathaway, Jennifer J; Enes Dapkevicius, Maria de L N; Miller, Ana Z; Kooser, Ara; Northup, Diana E; Jurado, Valme; Fernandez, Octavio; Saiz-Jimenez, Cesareo; Cheeptham, Naowarat

    2015-01-01

    Volcanic caves are filled with colorful microbial mats on the walls and ceilings. These volcanic caves are found worldwide, and studies are finding vast bacteria diversity within these caves. One group of bacteria that can be abundant in volcanic caves, as well as other caves, is Actinobacteria. As Actinobacteria are valued for their ability to produce a variety of secondary metabolites, rare and novel Actinobacteria are being sought in underexplored environments. The abundance of novel Actinobacteria in volcanic caves makes this environment an excellent location to study these bacteria. Scanning electron microscopy (SEM) from several volcanic caves worldwide revealed diversity in the morphologies present. Spores, coccoid, and filamentous cells, many with hair-like or knobby extensions, were some of the microbial structures observed within the microbial mat samples. In addition, the SEM study pointed out that these features figure prominently in both constructive and destructive mineral processes. To further investigate this diversity, we conducted both Sanger sequencing and 454 pyrosequencing of the Actinobacteria in volcanic caves from four locations, two islands in the Azores, Portugal, and Hawai'i and New Mexico, USA. This comparison represents one of the largest sequencing efforts of Actinobacteria in volcanic caves to date. The diversity was shown to be dominated by Actinomycetales, but also included several newly described orders, such as Euzebyales, and Gaiellales. Sixty-two percent of the clones from the four locations shared less than 97% similarity to known sequences, and nearly 71% of the clones were singletons, supporting the commonly held belief that volcanic caves are an untapped resource for novel and rare Actinobacteria. The amplicon libraries depicted a wider view of the microbial diversity in Azorean volcanic caves revealing three additional orders, Rubrobacterales, Solirubrobacterales, and Coriobacteriales. Studies of microbial ecology in

  7. Actinobacterial Diversity in Volcanic Caves and Associated Geomicrobiological Interactions

    PubMed Central

    Riquelme, Cristina; Marshall Hathaway, Jennifer J.; Enes Dapkevicius, Maria de L. N.; Miller, Ana Z.; Kooser, Ara; Northup, Diana E.; Jurado, Valme; Fernandez, Octavio; Saiz-Jimenez, Cesareo; Cheeptham, Naowarat

    2015-01-01

    Volcanic caves are filled with colorful microbial mats on the walls and ceilings. These volcanic caves are found worldwide, and studies are finding vast bacteria diversity within these caves. One group of bacteria that can be abundant in volcanic caves, as well as other caves, is Actinobacteria. As Actinobacteria are valued for their ability to produce a variety of secondary metabolites, rare and novel Actinobacteria are being sought in underexplored environments. The abundance of novel Actinobacteria in volcanic caves makes this environment an excellent location to study these bacteria. Scanning electron microscopy (SEM) from several volcanic caves worldwide revealed diversity in the morphologies present. Spores, coccoid, and filamentous cells, many with hair-like or knobby extensions, were some of the microbial structures observed within the microbial mat samples. In addition, the SEM study pointed out that these features figure prominently in both constructive and destructive mineral processes. To further investigate this diversity, we conducted both Sanger sequencing and 454 pyrosequencing of the Actinobacteria in volcanic caves from four locations, two islands in the Azores, Portugal, and Hawai'i and New Mexico, USA. This comparison represents one of the largest sequencing efforts of Actinobacteria in volcanic caves to date. The diversity was shown to be dominated by Actinomycetales, but also included several newly described orders, such as Euzebyales, and Gaiellales. Sixty-two percent of the clones from the four locations shared less than 97% similarity to known sequences, and nearly 71% of the clones were singletons, supporting the commonly held belief that volcanic caves are an untapped resource for novel and rare Actinobacteria. The amplicon libraries depicted a wider view of the microbial diversity in Azorean volcanic caves revealing three additional orders, Rubrobacterales, Solirubrobacterales, and Coriobacteriales. Studies of microbial ecology in

  8. Altered former alkalic carbonatite lava from Oldoinyo Lengai, Tanzania: Inferences for calcite carbonatite lavas

    NASA Astrophysics Data System (ADS)

    Dawson, J. B.; Garson, M. S.; Roberts, B.

    1987-08-01

    The active volcano Oldoinyo Lengai, Tanzania, is well known for its extrusions of alkalic carbonatite lava, first witnessed in 1960. An older carbonatite flow from the volcano was originally also rich in Na and K, but replacement of nyerereite by pirssonite as a result of leaching of these elements (together with soluble components such as SO3, Cl, and Rb) and addition of Ca has resulted in a rock intermediate in bulk composition between the unique 1960 Lengai lavas and calcite-rich carbonatite flows reported from other localities. Further replacement of Na by Ca could theoretically result in a pure calcite rock, and we suggest that the partially altered alkalic lava described here is the “missing link” between lavas that are now calcitic but which had a high alkali content when originally extruded. The suggested link between alkali carbonate precursors and present-day calcium carbonate “lavas” explains the apparent paradox between the existence of calcite-rich “flows” and the experimental evidence that denies the possibility of hot, liquid calcium carbonate.

  9. Age and speleogenesis of epigenic gypsum caves in the northern Apennines (Italy)

    NASA Astrophysics Data System (ADS)

    Columbu, Andrea; Chiarini, Veronica; De Waele, Jo; Drysdale, Russell; Forti, Paolo; Hellstrom, John; Woodhead, Jon

    2016-04-01

    Triassic and Messinian gypsum beds host the majority of the caves in the eastern flank of the northern Apennines. To date, more than six hundreds voids have been mapped, including the longest known epigenic gypsum cave system in the world (Spipola-Acquafredda, ~11 km of tunnels) (De Waele et al., 2013). Superimposed caves are typically sub-horizontal (Klimchouk, 2000) and connected through vertical shafts, reflecting the palaeo base-level variations. When preserved, river terraces at the surface lie at the same palaeo altitude of the base level and horizontal cave passages. Notwithstanding the well-known geology of the area known (Vai and Martini, 2001), the age of these caves has been greatly underestimated in the past. Considering the rapid dissolution of the gypsum and uplifting of the area, the start of speleogenesis activity was considered to have occurred during the last glacial age. The age of karst voids can be only indirectly estimated by the dating of the infilling sediments. U-Th dating on carbonate speleothems provides high-precision and accurate ages (Hellstrom, 2003; Scholz and Hoffmann, 2008). We thus applied this methodology to 20 speleothems coming from 14 different caves belonging to the Monte Tondo, Spipola Acquafredda, Castelnuovo, Stella-Rio Basino and Brisighella systems. The results show that: i) caves were forming since at least ~300 ka; ii) the peak of speleogenesis was reached during relatively cold climate stages, when rivers formed terraces at the surface and aggradation caused paragenesis in the stable cave levels (Columbu et al., 2015). Besides the significant contribution to the understanding of the Apennines evaporite karst evolution, this study (and its further advancement) may also refine knowledge of the local vs regional uplifting rates and base-level variations since the late Pleistocene (Wegmann and Pazzaglia, 2009). References Columbu, A., De Waele, J., Forti, P., Montagna, P., Picotti, V., Pons-Branchu, E., Hellstrom, J

  10. Topographic Attributes of Three Hawaiian Lava Flows: Implications for Evaluation of Lava Flow Emplacement on Mars

    NASA Astrophysics Data System (ADS)

    Zimbelman, J. R.

    2004-12-01

    Differential Global Positioning System surveys were carried out recently across portions of three lava flows on the Big Island of Hawaii. Transects crossed an entire flow in several cases, and in other cases provided detailed information about selected flow margins. The 1907 basalt (a'a) flow from the southwestern rift zone of Mauna Loa has easy access at several points via the Ocean View Estates road system; flow thickness ranges from about 1 m near the middle of the eastern flow lobe to more than 10 m toward the distal end of this flow. Several components of a benmoreite (alkali-rich basaltic andesite) flow complex from Mauna Kea were examined near the small community of Mana (with permission of the Parker Ranch management), on the western flank of the volcano. The flows are more than 14,000 years old and completely covered with soil more than a meter thick, but flow morphology at the decameter scale remains very evident in aerial photographs; some benmoreite flows have up to 30 m of relief along their middle reaches. A trachyte flow more than 100,000 years old extends down slope from Puu Waawaa, on the northern flank of Hualalai; Puu Anahulu represents a very advanced stage of magmatic differentiation that resulted in a flow complex with more than 120 m of relief at its southern margin. Width/thickness represents a good discriminator between these three Hawaiian lava flows. Unfortunately, width is often the most difficult parameter to measure remotely for flows on other planets. Recent imaging data from the Thermal Emission Imaging System on the Mars Odyssey spacecraft reveal important new details of lava flows in the Tharsis region of Mars, some of which can be combined with elevation information from the Mars Orbiter Laser Altimeter. The precise topographic characteristics of diverse Hawaiian lava flows provide a new tool for evaluating the potential emplacement conditions for some Martian lava flows, which appear to be more consistent with the basalt to

  11. Temperature as tracer of the hydraulic dynamic of an anchialine cave (coastal submerged cave) of Krka Estuary (Croatia)

    NASA Astrophysics Data System (ADS)

    Domínguez-Villar, David; Cukrov, Neven; Krklec, Kristina

    2016-04-01

    A series of temperature, conductivity and water level loggers were used to characterize the hydraulic dynamic of a submerged cave (anchialine cave) in Krka Estuary. Litno Cave is a sub-horizontal gallery, less than 5 m in diameter and one meter below sea level. Apart from some sections that contain occasional air pockets under the ceiling, the cave is completely flooded. Outflow discharge through the cave is continuous during the year (>30 l/s). During several months vertical temperature profiles were measured in three locations inside the cave at 20, 60 and 100 m from the cave entrance, whereas another vertical profile was set in the estuary in front of the cave. Thermometers from the estuary measured thermal gradients to characterize position and evolution of the thermocline up to a depth of 3.5 m. Tides measured in the estuary are synchronous to those recorded in the cave and their amplitudes (20 to 40 cm in the estuary) are the same or smaller depending on cave outflow discharge. Records of cave water temperature show a non-linear response to tides due to the vertical displacement of the thermocline. During neap tides the thermocline was located in the aquifer below the cave, whereas during spring tides only thermometers in the top meter of the cave were not affected by the thermocline vertical displacement. After the first significant rains of the hydrological year, the freshwater contribution increased the cave outflow discharge by one order of magnitude. Thus, conductivity decreased in response to rains from 16000 ±1000 μS/cm to <700 μS/cm at the bottom of the cave. Under these conditions variability of cave water temperature was less than 0.1 °C, although a 0.4 °C long-term variability was recorded. These data shows that the discharge of freshwater to the estuary determines the dynamic of this submerged cave, limiting the influence of estuarine water intrusion in the coastal aquifer and the impact of tides. This research shows that temperature is a

  12. Lava tube shatter rings and their correlation with lava flux increases at Kīlauea Volcano, Hawai‘i

    USGS Publications Warehouse

    Orr, T.R.

    2011-01-01

    Shatter rings are circular to elliptical volcanic features, typically tens of meters in diameter, which form over active lava tubes. They are typified by an upraised rim of blocky rubble and a central depression. Prior to this study, shatter rings had not been observed forming, and, thus, were interpreted in many ways. This paper describes the process of formation for shatter rings observed at Kīlauea Volcano during November 2005–July 2006. During this period, tilt data, time-lapse images, and field observations showed that episodic tilt changes at the nearby Pu‘u ‘Ō‘ō cone, the shallow magmatic source reservoir, were directly related to fluctuations in the level of lava in the active lava tube, with periods of deflation at Pu‘u ‘Ō‘ō correlating with increases in the level of the lava stream surface. Increases in lava level are interpreted as increases in lava flux, and were coincident with lava breakouts from shatter rings constructed over the lava tube. The repetitive behavior of the lava flux changes, inferred from the nearly continuous tilt oscillations, suggests that shatter rings form from the repeated rise and fall of a portion of a lava tube roof. The locations of shatter rings along the active lava tube suggest that they form where there is an abrupt decrease in flow velocity through the tube, e.g., large increase in tube width, abrupt decrease in tube slope, and (or) sudden change in tube direction. To conserve volume, this necessitates an abrupt increase in lava stream depth and causes over-pressurization of the tube. More than a hundred shatter rings have been identified on volcanoes on Hawai‘i and Maui, and dozens have been reported from basaltic lava fields in Iceland, Australia, Italy, Samoa, and the mainland United States. A quick study of other basaltic lava fields worldwide, using freely available satellite imagery, suggests that they might be even more common than previously thought. If so, this confirms that episodic

  13. Pressure Analysis for LAVA-OVEN

    NASA Technical Reports Server (NTRS)

    Cendana, Donna Q.

    2014-01-01

    The Lunar Advanced Volatiles Analysis (LAVA) and the Oxygen Volatiles Extraction Node (OVEN) are subsystems included in the Regolith Environment Science, and Oxygen Lunar Volatiles Extraction (RESOLVE) payload bound for the Moon in 2019. This Resource Prospector Mission (RPM) has the objective of landing on a shadowed region of the Moons South Pole to collect data and determine whether the resources could be effectively used for space exploration systems. The quantification of the resources will help understand if it can adequately minimize materials carried from Earth by: providing life support, propellants, construction materials or energy supply to the payload or crew. This paper outlines the procedures done for the pressure analysis of the LAVA-OVEN (LOVEN) Integration Testing. The pressure analysis quantifies how much gases and water are present in the sample tested during the Engineering Testing Unit (ETU) phase of instrument development. Ultimately the purpose of these tests is to improve the estimate of the amount of water in each Lunar sample and reduce the time necessary for this estimate. The governing principle that was used for the analysis is the Ideal Gas Law, PV=nRT where P stands for pressure, V for volume, n for number of moles, R being the gas constant and T for temperature. We also estimate the errors involved in these measured and derived quantities since a key objective of the mission is to estimate the quantity of volatiles present in the lunar samples introduced into OVEN.

  14. Crystallization during emplacement of lava flows

    NASA Technical Reports Server (NTRS)

    Crisp, J.

    1991-01-01

    Thermal models of lava flows provide a way of estimating emplacement durations and eruption rates of planetary lava flows, which can help constrain magma ascent, rheology and composition. Most of the models that have been developed consider only the effects of cooling by radiation. However, heating due to crystallization can be a large component of the overall heat budget of a flow. Little is known about the amount of crystallization and latent heating during flow advance. Crystal size distribution (CSD) measurements were made to quantify and study the effects of crystallization in the 1984 Mauna Loa flow. For flows on Mars, we must assume that the amount of crystallization is similar to that in terrestrial flows and place minimum and maximum bounds on the latent heat effect. Unfortunately, as examples given here show, there can be anywhere from 0 to 60 percent crystallization during flow advance. To improve constraints for Martian flows, we need to search for correlations in terrestrial flows between flow morphology and the amount of crystallization during emplacement.

  15. Peralkaline silicate lavas at Oldoinyo Lengai, Tanzania

    NASA Astrophysics Data System (ADS)

    Klaudius, Jurgis; Keller, Jörg

    2006-10-01

    A detailed study of Oldoinyo Lengai has led to the recognition of two major cone-building stages. An early, predominantly phonolitic stage, Lengai I, forms the southern cone. The recent nephelinitic Lengai II developed following a major sector collapse event over Lengai I. Petrography of Lengai II lavas show that nephelinite is combeite- and wollastonite-bearing. All Oldoinyo Lengai lavas are peralkaline and highly evolved in terms of low Mg#, Ni and Cr values. Within the unique Lengai II combeite-wollastonite-nephelinite (CWN) peralkalinity increases with time to extreme values (Na + K)/Al = 2.36. Mineralogical expression of peralkalinity is the presence of combeite and Na-rich clinopyroxene. In addition, exceptionally high Fe 2O 3 (up to 10.28 wt.%) in nepheline is an indicator for alumina deficiency. Combeite also shows high Fe 3+. Phonolite and CWN of Lengai I and Lengai II show similarly enriched LILE and LREE values and generally parallel patterns in PM normalized and REE plots.

  16. What factors control the superficial lava dome explosivity?

    NASA Astrophysics Data System (ADS)

    Boudon, Georges; Balcone-Boissard, Hélène; Villemant, Benoit; Morgan, Daniel J.

    2015-04-01

    Dome-forming eruption is a frequent eruptive style; lava domes result from intermittent, slow extrusion of viscous lava. Most dome-forming eruptions produce highly microcrystallized and highly- to almost totally-degassed magmas which have a low explosive potential. During lava dome growth, recurrent collapses of unstable parts are the main destructive process of the lava dome, generating concentrated pyroclastic density currents (C-PDC) channelized in valleys. These C-PDC have a high, but localized, damage potential that largely depends on the collapsed volume. Sometimes, a dilute ash cloud surge develops at the top of the concentrated flow with an increased destructive effect because it may overflow ridges and affect larger areas. In some cases, large lava dome collapses can induce a depressurization of the magma within the conduit, leading to vulcanian explosions. By contrast, violent, laterally directed, explosions may occur at the base of a growing lava dome: this activity generates dilute and turbulent, highly-destructive, pyroclastic density currents (D-PDC), with a high velocity and propagation poorly dependent on the topography. Numerous studies on lava dome behaviors exist, but the triggering of lava dome explosions is poorly understood. Here, seven dome-forming eruptions are investigated: in the Lesser Antilles arc: Montagne Pelée, Martinique (1902-1905, 1929-1932 and 650 y. BP eruptions), Soufrière Hills, Montserrat; in Guatemala, Santiaguito (1929 eruption); in La Chaîne des Puys, France (Puy de Dome and Puy Chopine eruptions). We propose a new model of superficial lava-dome explosivity based upon a textural and geochemical study (vesicularity, microcrystallinity, cristobalite distribution, residual water contents, crystal transit times) of clasts produced by these key eruptions. Superficial explosion of a growing lava dome may be promoted through porosity reduction caused by both vesicle flattening due to gas escape and syn-eruptive cristobalite

  17. A biosignature suite from cave pool precipitates, Cottonwood Cave, New Mexico.

    PubMed

    Melim, L A; Liescheidt, R; Northup, D E; Spilde, M N; Boston, P J; Queen, J M

    2009-11-01

    Calcite cave pool precipitates often display a variety of potential biosignatures from the macroscopic to the submicroscopic. A fossil cave pool in Cottonwood Cave, New Mexico, exhibits older stalactites and stalagmites that are completely coated in brown, laminated calcitic crust that extends down as pool fingers and u-loops. The pool fingers and u-loops are mainly micrite to clotted micrite, some recrystallized to microspar, with some isopachous spar layers. Micrite, particularly clotted micrite, is usually interpreted by carbonate workers as microbial in origin. Scanning electron microscopy examination of etched pool fingers, u-loops, and the brown crust revealed abundant calcified microbial filaments and biofilm. Energy dispersive X-ray analysis showed that these features have excess carbon, above that found in pure calcite. Independent carbon analysis indicated that these same samples contain up to 0.2% organic carbon. Since pool fingers hang down but form underwater, we hypothesize they are biogenic with hanging microbial filaments or biofilm acting as nuclei for calcite precipitation. Because of the abundance of micrite and fossil filaments, we further hypothesize that these pendant features formed during a period of plentiful nutrients and active hydrological activity when the pool was literally dripping with microbial slime. Although each of these lines of evidence could be interpreted in other ways, their combined weight strongly suggests the cave pool precipitates in Cottonwood Cave are biogenic. These investigations can be used to help inform extraterrestrial life-detection studies. PMID:19968466

  18. The explosive origin of obsidian lava (Invited)

    NASA Astrophysics Data System (ADS)

    Castro, J. M.; Bindeman, I. N.; Tuffen, H.; Schipper, C.

    2013-12-01

    A long-standing challenge in volcanology has been to explain why explosive eruptions of rhyolite magma transition into outpourings of lava. Many studies suggest that lava is the product of non-explosive processes that allow magmatic vapour to escape in an open-system manner without wholesale fragmentation. Recent eruptions at Chaitén and Cordón Caulle volcanoes have shown that effusive rhyolites are anything but 'non-explosive' and may erupt simultaneously with vigourous pyroclastic fountains for months from a common vent. This behaviour implies that pyroclastic processes play a critical if not dominant role in degassing magma sufficiently such that it erupts effusively. Here we use H-isotope and bulk H2O measurements paired with textural evidence from the 2008 Chaitén and 2011 Cordón Caulle eruptions to demonstrate that effusion requires explosion(s)--lavas are the direct product of brittle deformation that fosters batched degassing into transient pyroclastic channels that repetitively and explosively vent from effusing lava. Evidence for cyclical brecciation and collapse of porous and permeable magmatic foams is abundant in the textures and structures of tuffisites--ash and lapilli-filled pyroclastic channels--found in volcanic bombs at both Chaitén and Cordón Caulle. We have used FTIR and a TCEA-MAT 253 system to precisely measure total water and D/H in erupted glass. Bulk H2O measurements on tuffisite and adjacent bomb obsidian indicate significantly lower H2O (~0.2-1.0 wt.%) in the tuffisite veins. These depletions imply effective local degassing and rapid advective transport of exsolved vapour through the veins. The H-isotopic signatures of tuffisites are also different from the hosting material insofar as being enriched in deuterium (up to -20‰). Such deuterium enrichments are inconsistent with isotope fractionation during both closed- and open-system degassing, but can be explained if an abundant and more primitive volatile phase from less degassed

  19. 222Rn variations in Mystery Cave, Minnesota

    USGS Publications Warehouse

    Lively, R.S.; Krafthefer, B.C.

    1995-01-01

    222Rn concentrations and meteorological parameters were measured at 4- h intervals over a 2-y period in Mystery Cave, southeastern Minnesota. Continuous radon monitors and meteorological sensors connected to data loggers were installed at several locations along commercial tour routes. 222Rn concentrations ranged as high as 25 kBq m-3 in summer and 20 kBq m-3 in winter. Average winter concentrations were lower than summer by at least a factor of two. Seasonal radon variations were correlative with outside air temperatures. During the winter, radon concentrations were observed to fluctuate periodically by factors of 20 or more in under 24 h. Both the long- and short-term variations are correlative with temperature- induced mixing of cave air with surface air.

  20. Palaeolithic paintings. Evolution of prehistoric cave art.

    PubMed

    Valladas, H; Clottes, J; Geneste, J M; Garcia, M A; Arnold, M; Cachier, H; Tisnérat-Laborde, N

    2001-10-01

    Sophisticated examples of European palaeolithic parietal art can be seen in the caves of Altamira, Lascaux and Niaux near the Pyrenees, which date to the Magdalenian period (12,000-17,000 years ago), but paintings of comparable skill and complexity were created much earlier, some possibly more than 30,000 years ago. We have derived new radiocarbon dates for the drawings that decorate the Chauvet cave in Vallon-Pont-d'Arc, Ardèche, France, which confirm that even 30,000 years ago Aurignacian artists, already known as accomplished carvers, could create masterpieces comparable to the best Magdalenian art. Prehistorians, who have traditionally interpreted the evolution of prehistoric art as a steady progression from simple to more complex representations, may have to reconsider existing theories of the origins of art. PMID:11586348

  1. Biomineralization and biosignatures of coralloid-type speleothems from lava tubes of Galapagos Islands: evidences on the fossil record of prokaryotes

    NASA Astrophysics Data System (ADS)

    Miller, Ana Z.; Garcia-Sanchez, Angela M.; Pereira, Manuel F. C.; Gazquez, Fernando; Calaforra, José M.; Forti, Paolo; Toulkeridis, Theofilos; Martínez-Frías, Jesús; Saiz-Jimenez, Cesareo

    2016-04-01

    Lava tubes have traditionally been considered of little interest from a mineralogical point of view. Recently, this type of volcanic caves has received particular attention because lava tubes have been described on Mars. Speleothems, or secondary mineral deposits in lava tubes are mainly composed of siliceous minerals. Coralloid-type speleothems are found either on basaltic cave walls or on the surface of other speleothems. Several authors attribute a microbially mediated origin to their formation. This type of speleothems was recorded within Royal Palm Cave of Santa Cruz Island in Galapagos Archipelago (Ecuador), a lava tube 600 m long, 5 to 15 m height and 2 to 10 m width. The Galapagos Islands are an archipelago of 19 volcanic islands located some 1500 km west of Ecuador, in the Pacific Ocean. These islands host one of the most biodiverse settings on Earth, studied by Charles Darwin. Beige and greyish small coralloids were collected in Royal Palm Cave and analysed by field emission scanning electron microscopy with energy dispersive X-ray spectroscopy (FESEM-EDS), X-ray micro-computed tomography (micro-CT) and mineralogical analyses for morphological, 3D microstructural and compositional characterization, as well as for assessing microbe-mineral interactions and biogenicity. In addition, 16S rRNA gene analyses were performed to identify microbial communities associated with the coralloid-type speleothems. The coralloids showed internal compositional zonation along the growth direction of the speleothems, according to micro-CT data. Internal layering was clearly discernable by the differences in opacity of the distinct mineralogical phases to X-rays, being dominated by alteration products of siliceous composition, whereas more opaque phases, usually Ca-rich minerals, were dominant in the outermost part of the speleothems. X-ray diffraction and infrared spectroscopy reinforced that the first stage of deposition is mainly composed of opal A and clay minerals

  2. Cyclic pressurisation of lava dome rocks. Laboratory results and implications for lava dome monitoring

    NASA Astrophysics Data System (ADS)

    Dainty, M. L.; Smith, R.; Sammonds, P.; Meredith, P. G.

    2009-12-01

    Lava domes are frequently subjected to cyclic heating and pressurisation. These processes may weaken the dome rocks, leading to collapse of the lava dome or explosion and extrusion events caused by unplugging of the magma conduit. By subjecting lava dome rocks to cyclic loading and heating in the laboratory, we can investigate how these processes affect the elastic moduli and strength of the dome rocks. These elastic moduli are crucial parameters for determining how the deformation measured at a volcano relates to the pressurisation and stress. Recording acoustic emissions (AE) during these cyclic loading tests can reveal when the cracking and damage occurs and indicate expected patterns in seismicity during cyclic pressurisation of lava domes. For this laboratory investigation of cyclic loading and heating of lava dome rocks, samples with four different extrusion dates within the 2004-2008 eruption of Mount St Helens were used. This allowed us to also investigate how the mechanical properties of this lava dome changed with time. For each timed sample, four 62.5 mm long x 25 mm diameter cores were deformed in uniaxial compression. The first sample was simply loaded to failure at a constant rate, to obtain the strength and elastic moduli. Of the remaining three cores from each sample, one was slowly heated and cooled to 900°C and one to 600°C (and the other not heated). The three cores from each sample were then initially loaded to 40 MPa at a constant rate and then unloaded to 5 MPa. They were then sequentially reloaded and unloaded at the same rate with the peak stress in each cycle increased by 5 MPa until failure. For all samples, the core loaded to failure with no cycling was stronger than those subjected to cyclic loading. However, there was no weakening or reduction in elastic moduli seen for the samples subjected to a heating cycle before cyclic loading. The sample extruded in 2004 compared to the later ones from 2005 and 2006, was the weakest at 60 to 70

  3. An American scientist visits the Altamira cave in northern Spain

    SciTech Connect

    Wilkening, M.

    1981-12-01

    The Altamira Cave is internationally known for its remarkable Stone Age paintings. It is located in the brow of a hill overlooking the village of Santillana del Mar which is nestled among green rolling hills near the coast of northern Spain. This report gives a brief description of the Cave and its paintings, the nature of the deterioration that has resulted in the closing of the cave to tourists, and the scientific studies being undertaken to help preserve the paintings.

  4. Cave biosignature suites: microbes, minerals, and Mars.

    PubMed

    Boston, P J; Spilde, M N; Northup, D E; Melim, L A; Soroka, D S; Kleina, L G; Lavoie, K H; Hose, L D; Mallory, L M; Dahm, C N; Crossey, L J; Schelble, R T

    2001-01-01

    Earth's subsurface offers one of the best possible sites to search for microbial life and the characteristic lithologies that life leaves behind. The subterrain may be equally valuable for astrobiology. Where surface conditions are particularly hostile, like on Mars, the subsurface may offer the only habitat for extant lifeforms and access to recognizable biosignatures. We have identified numerous unequivocally biogenic macroscopic, microscopic, and chemical/geochemical cave biosignatures. However, to be especially useful for astrobiology, we are looking for suites of characteristics. Ideally, "biosignature suites" should be both macroscopically and microscopically detectable, independently verifiable by nonmorphological means, and as independent as possible of specific details of life chemistries--demanding (and sometimes conflicting) criteria. Working in fragile, legally protected environments, we developed noninvasive and minimal impact techniques for life and biosignature detection/characterization analogous to Planetary Protection Protocols. Our difficult field conditions have shared limitations common to extraterrestrial robotic and human missions. Thus, the cave/subsurface astrobiology model addresses the most important goals from both scientific and operational points of view. We present details of cave biosignature suites involving manganese and iron oxides, calcite, and sulfur minerals. Suites include morphological fossils, mineral-coated filaments, living microbial mats and preserved biofabrics, 13C and 34S values consistent with microbial metabolism, genetic data, unusual elemental abundances and ratios, and crystallographic mineral forms. PMID:12448994

  5. Lava Flows on Io: Modelling Cooling After Solidification

    NASA Technical Reports Server (NTRS)

    Davies, A. G.; Matson, D. L.; Veeder, G. J.; Johnson, T. V.; Blaney, D. L.

    2003-01-01

    We have modeled the cooling of lava bodies on Io after solidification of the lava, a process that has been little explored since Carr (1986). With recent estimates of lava flow thicknesses on Io ranging from 1 m to 10 m, the modeling of thermal emission from active volcanism must take into account the cooling behaviour after the solidification of the lava, which we model using a finite-element model. Once a lava body is fully solidified, the surface temperature decreases faster, as heat loss is no longer buffered by release of latent heat. This is significant as observed surface temperature is often the only clue available to determine lava surface age. We also find that cooling from the base of the lava is an important process that accelerates the solidification of a flow and therefore subsequent cooling. It is necessary to constrain the cooling process in order to better understand temperature-area relationships on Io's surface and to carry out stochastic modelling of lava flow emplacement.

  6. Small domes on Venus: probable analogs of Icelandic lava shields

    USGS Publications Warehouse

    Garvin, James B.; Williams, Richard S., Jr.

    1990-01-01

    On the basis of observed shapes and volumetric estimates, we interpret small, dome-like features on radar images of Venus to be analogs of Icelandic lava-shield volcanoes. Using morphometric data for venusian domes in Aubele and Slyuta (in press), as well as our own measurements of representative dome volumes and areas from Tethus Regio, we demonstrate that the characteristic aspect ratios and flank slopes of these features are consistent with a subclass of low Icelandic lava-shield volcanoes (LILS ). LILS are slightly convex in cross-section with typical flank slopes of ∼3°. Plausible lava-shield-production rates for the venusian plains suggest formation of ∼53 million shields over the past 0.25 Ga. The cumulative global volume of lava that would be associated with this predicted number of lava shields is only a factor of 3–4 times that of a single oceanic composite shield volcano such as Mauna Loa. The global volume of all venusian lava shields in the 0.5–20-km size range would only contribute a meter of resurfacing over geologically significant time scales. Thus, venusian analogs to LILS may represent the most abundant landform on the globally dominant plains of Venus, but would be insignificant with regard to the global volume of lava extruded. As in Iceland, associated lavas from fissure eruptions probably dominate plains volcanism and should be evident on the higher resolution Magellan radar images.

  7. Joint analysis of deformation, gravity, and lava lake elevation reveals temporal variations in lava lake density at Kilauea Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Carbone, Daniele; Poland, Michael; Patrick, Matthew

    2015-04-01

    We find a tight correlation between (i) changes in lava level within the summit eruptive vent at Kilauea Volcano, Hawaii, observed for at least 2 years since early 2011, and (ii) ground deformation in the vicinity of the vent. The observed correlation indicates that changing pressure within the shallow magma reservoir feeding the lava lake influences both deformation and lava level. However, those two parameters are related to chamber pressure through different properties, namely, the density of the lava filling the vent (for the lava level) and the size/position of the reservoir plus the elastic parameters of the host rock (for the deformation). Joint analyses in the time and frequency domains of lava level (determined from thermal camera imagery of the lava lake) and tilt measured on a borehole instrument (~2 km from the summit vent) reveal a good correlation throughout the studied period. The highest correlation occurs over periods ranging between 1 and 20 days. The ratio between lava level and tilt is not constant over time, however. Using data from a continuously recording gravimeter located near the rim of the summit eruptive vent, we demonstrate that the tilt-lava level ratio is controlled by the fluctuations in the density of the lava inside the vent (i.e., its degree of vesicularity). A second continuous gravimeter was installed near the summit eruptive vent in 2014, providing a new observation point for gravity change associated with summit lava lave activity to test models developed from the previously existing instrument. In addition, a continuous gravimeter was installed on the rim of the Puu Oo eruptive vent on Kilauea's East Rift Zone in 2013. Puu Oo is connected via the subvolcanic magma plumbing system to the summit eruptive vent and often deforms in concert with the summit. This growing network of continuously recording gravimeters at Kilauea can be used to examine correlations in gravity change associated with variations in eruptive activity

  8. International comparison of cave radon concentrations identifying the potential alpha radiation risks to British cave users

    SciTech Connect

    Hyland, R.; Gunn, J.

    1994-08-01

    Elevated concentrations of {sup 222}Rn have been recorded in many limestone caves throughout the world. As prolonged exposure to high radon concentrations has been linked to cancer and tumors, particularly of the lung, a national survey of radon in British caves was undertaken. Passive radon detectors were exposed at 250 sites in 47 caves over four 7-d sampling periods. Mean concentrations ranging from 454-8,868 Bq m{sup {minus}3} were recorded. In one system, in the Peak District, radon concentrations of 155,000 Bq m{sup {minus}3} were recorded. The results indicate that the potential radiation dose from a single 4-h trip could exceed the national average annual background radiation dose (for the UK) from radon of 1.25 mSv. 18 refs., 3 tabs.

  9. International comparison of cave radon concentrations identifying the potential alpha radiation risks to British cave users.

    PubMed

    Hyland, R; Gunn, J

    1994-08-01

    Elevated concentrations of 222Rn have been recorded in many limestone caves throughout the world. As prolonged exposure to high radon concentrations has been linked to cancer and tumors, particularly of the lung (National Academy of Science 1988; Eatough and Henshaw 1990), a national survey of radon in British caves was undertaken. Passive radon detectors were exposed at 250 sites in 47 caves over four 7-d sampling periods. Mean concentrations ranging from 454-8,868 Bq m-3 were recorded. In one system, in the Peak District, radon concentrations of 155,000 Bq m-3 were recorded. The results indicate that the potential radiation dose from a single 4-h trip could exceed the national average annual background radiation dose (for the UK) from radon of 1.25 mSv. PMID:8026972

  10. Pre-excavation studies of prehistoric cave sites by magnetic prospecting

    NASA Astrophysics Data System (ADS)

    Itkis., Sonia; Matskevich, Zinovii; Meshveliani, Tengiz

    2014-05-01

    Detailed magnetic survey was performed for caves study in Israel (1995-1996) within the framework of the Beit Shemesh Regional Project (Judean Shephelah). The experience accumulated in Israel we applied later (2010) in two Georgian prehistoric cave sites: Cherula and Kotias-Klde. The magnetic method is based on the contrast in magnetic properties between a target object (e.g., buried archaeological feature) and the host medium (i.e, the surrounding bedrock and soil). The feasibility of the magnetic method for cave revealing was evaluated by magnetic susceptibility (κ) measurements of surrounding soil and rocks, and archaeological features: stones making up the walls, ceramic fragments and cave fill. According to data obtained, the κ of soil within caves (cave fill) is higher than that of surrounding soil. The enhancement of cave fill κ occurs because processes associated with human habitation: repeated heating and accumulation of organic debris. Both these processes provide good conditions for the conversion of the iron oxide found within the soil to a strongly ferromagnetic form (Mullins, 1977; Maher, 1986; Dalan and Banerjee, 1998, Itkis and Eppelbaum, 1999; Itkis, 2003) The presence of highly magnetic ceramics in caves also enhances magnetic contrast between practically non-magnetic bed rock (chalk in Ramat Beit Shemesh Site (Israel) and limestone (Georgian sites) and the cave fill, increasing the potential of the magnetic method to reveal caves (Itkis, 2011). Based on magnetic survey results, an excavation revealed a cave with a large amount of well preserved pottery and finds typical of the Early Bronze Age. Both studied cave sites in Georgia were located in Chiatura region of Imeretia province. Cherula site is a karstic rockshelter with a single chamber, ca 100 sq. m. The site was briefly tested in 1970s'. The area excavated in 2010 went to the depth of 60 cm below the present day surface; the limestone bedrock was not reached. The excavation revealed

  11. Natural and human impacts on invertebrate communities in Brazilian caves.

    PubMed

    Ferreira, R L; Horta, L C

    2001-02-01

    Species richness, abundance, distribution and similarity between cave invertebrate communities were compared among seven caves located in the Peruaçu River valley, north of Minas Gerais State, Brazil. Such comparisons aimed to determinate the degree of biological complexity in the sampled caves, calculated by the "Index of Biological Complexity in Caves", presented in this manuscript. The presence of potential or real impacts on the cave fauna was also investigated. A total of 1,468 individuals belonging to 57 families of: Acarina, Pseudoscorpionida, Araneida, Opilionida, Amblypygi, Isopoda, Geophilomorpha, Scutigeromorpha, Spirostreptida, Coleoptera, Collembola, Diptera, Dictyoptera, Ephemeroptera, Ensifera, Heteroptera, Hymenoptera, Lepidoptera, Plecoptera, Psocoptera, and Trichoptera was collected. Caves with higher resource availability (as those hidrologicaly actives) had a higher biological complexity than those with less resource. There are two types of impacts that occur in the area: the natural (geological) and the anthropic, as intense "stepping" and visitation or use of cave entrances as cattle shelters. There are caves with different preservation degrees in the area, with invertebrate communities in varied complexity states. The communities of these caves undoubtedly deserve care, since the area is extremely important in the Brazilian biospeleological context. PMID:11340457

  12. Measuring radon concentrations and estimating dose in tourist caves.

    PubMed

    Martín Sánchez, A; de la Torre Pérez, J; Ruano Sánchez, A B; Naranjo Correa, F L

    2015-11-01

    Caves and mines are considered to be places of especial risk of exposure to (222)Rn. This is particularly important for guides and workers, but also for visitors. In the Extremadura region (Spain), there are two cave systems in which there are workers carrying out their normal everyday tasks. In one, visits have been reduced to maintain the conditions of temperature and humidity. The other comprises several caves frequently visited by school groups. The caves were radiologically characterised in order to estimate the dose received by workers or possible hazards for visitors. PMID:25948834

  13. 6. Photographic copy of historic photograph (from Wind Cave National ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Photographic copy of historic photograph (from Wind Cave National Park), photographer unknown, date unknown. Route 87, Pigtail Bridge, elevation. - Pigtail Bridge, Hot Springs, Fall River County, SD

  14. Legal protection for caves in the United States

    NASA Astrophysics Data System (ADS)

    Huppert, G. N.

    1995-09-01

    This study reviews significant state and federal laws that can be used to protect karst, caves, and associated unique minerals and biota. The first state cave protection act was passed in Colorado in 1883; unfortunately it was repealed in 1971. From that modest beginning there are now a total of 22 states, Puerto Rico, and the Cherokee Nation that have specific cave protection acts. Most of these have been legislated during the last 20 years. There are a number of laws on the federal level that can be used for cave protection. The most important of these is the Federal Cave Resources Protection Act of 1988, which mandates cave conservation for many federal land management agencies. The Endangered Species Act of 1973 and the Federal Archaeological Resources Protection Act of 1976 can also be of significant use in the conservation of caves on federal land. The effects of these acts are variable. One factor is how important agency officials and law enforcement officers regard caves. It has not been unusual that little was done in the way of protection or prosecution even when the perpetrators have been apprehended. This attitude is changing rapidly primarily because those involved in enforcing the laws have been educated to the uniqueness and values of caves and their contents.

  15. Analysis of inflated submarine and sub-lacustrine Pahoehoe lava flows using high-resolution bathymetric and lidar data

    NASA Astrophysics Data System (ADS)

    Deschamps, A.; Soule, S. A.; Le Saout, M.; Allemand, P.

    2012-12-01

    , the Hells Half Acres Holocene lava flows, Idaho, display similar morphology as EPR flows, with sheet lavas, flow lobes 5-8 m high and approximately 100 m wide, and pressure ridges. Similar flows are observed in the ESRP: Craters of the Moon, Wapi, and Cerro Grande lava flows for example. In Oregon, Potholes, Devils Garden, Diamond Craters, Deschute River, Owyhee River, Jordan Crater flows are also strictly comparable. In Iceland, Lake Mytvan lava flows, for example, were emplaced in sublacustrine environments, and Budahraun flows in Snaefellness were emplaced at the coast below the sea level. The common point of these presently "aerial" lava flow is their emplacement in lakes, paleo-lakes and river beds, thus in "wet" environment, often controlled by rivers and their tributaries. A more efficient cooling of the lava lobes in wet environment probably triggers the development of strong and plastic margins due to cooling, which resists continued movement of the flow, whereas a thinner margin developing in aerial environment may favor lobe break out when internal pressure rises above the tensile strength of the crust. We propose a theoretical model for these lava flow emplacement on sub-horizontal basement.

  16. Analysis of inflated submarine and sub-lacustrine Pahoehoe lava flows using high-resolution bathymetric and lidar data (Invited)

    NASA Astrophysics Data System (ADS)

    Deschamps, A.; Van Vliet-Lanoe, B.; Soule, S. A.; Allemand, P.; Le Saout, M.; Delacourt, C.

    2013-12-01

    . For example, the Hells Half Acres Holocene lava flows, Idaho, display similar morphology as EPR flows, with sheet lavas, flow lobes 5-8 m high and approximately 100 m wide, and pressure ridges. Similar flows are observed in the ESRP: Craters of the Moon, Wapi, and Cerro Grande lava flows for example. In Oregon, Potholes, Devils Garden, Diamond Craters, Deschute River, Owyhee River, Jordan Crater flows are also strictly comparable. In Iceland, Lake Mytvan lava flows, for example, were emplaced in sublacustrine environments, and Budahraun flows in Snaefellness were emplaced at the coast below the sea level. The common point of these presently "aerial" lava flow is their emplacement in lakes, paleo-lakes and river beds, thus in "wet" environment, often controlled by rivers and their tributaries. A more efficient cooling of the lava lobes in wet environment probably triggers the development of strong and plastic margins due to cooling, which resists continued movement of the flow, whereas a thinner margin developing in aerial environment may favor lobe break out when internal pressure rises above the tensile strength of the crust. We propose a theoretical model for these lava flow emplacement on sub-horizontal basement.

  17. Pre-excavation studies of prehistoric cave sites by magnetic prospecting

    NASA Astrophysics Data System (ADS)

    Itkis., Sonia; Matskevich, Zinovii; Meshveliani, Tengiz

    2014-05-01

    Detailed magnetic survey was performed for caves study in Israel (1995-1996) within the framework of the Beit Shemesh Regional Project (Judean Shephelah). The experience accumulated in Israel we applied later (2010) in two Georgian prehistoric cave sites: Cherula and Kotias-Klde. The magnetic method is based on the contrast in magnetic properties between a target object (e.g., buried archaeological feature) and the host medium (i.e, the surrounding bedrock and soil). The feasibility of the magnetic method for cave revealing was evaluated by magnetic susceptibility (κ) measurements of surrounding soil and rocks, and archaeological features: stones making up the walls, ceramic fragments and cave fill. According to data obtained, the κ of soil within caves (cave fill) is higher than that of surrounding soil. The enhancement of cave fill κ occurs because processes associated with human habitation: repeated heating and accumulation of organic debris. Both these processes provide good conditions for the conversion of the iron oxide found within the soil to a strongly ferromagnetic form (Mullins, 1977; Maher, 1986; Dalan and Banerjee, 1998, Itkis and Eppelbaum, 1999; Itkis, 2003) The presence of highly magnetic ceramics in caves also enhances magnetic contrast between practically non-magnetic bed rock (chalk in Ramat Beit Shemesh Site (Israel) and limestone (Georgian sites) and the cave fill, increasing the potential of the magnetic method to reveal caves (Itkis, 2011). Based on magnetic survey results, an excavation revealed a cave with a large amount of well preserved pottery and finds typical of the Early Bronze Age. Both studied cave sites in Georgia were located in Chiatura region of Imeretia province. Cherula site is a karstic rockshelter with a single chamber, ca 100 sq. m. The site was briefly tested in 1970s'. The area excavated in 2010 went to the depth of 60 cm below the present day surface; the limestone bedrock was not reached. The excavation revealed

  18. Some deep caves in Biokovo Mountain (Croatia)

    NASA Astrophysics Data System (ADS)

    Garasic, Mladen; Garasic, Davor

    2014-05-01

    The investigation of 3 caves explored more than 1000 meters in depth in the Dinaric karst area in Croatia, has been in progress for a considerable period of time. These are complex speleological features situated in the longest mountain range of the Dinaric karst, i.e. at the Northern Velebit mountain range. In fact, these caves have been studied for over two decades now. The first one is a cave system of Lukina jama (Luke's Cave) - Trojama cave, which has been investigated until the depth of 1421 meters (Jalžić, 2007; Šmida, 1993). Its total length is 3731 meters and a new expedition will soon continue to investigate this pit through speleodiving in siphons. The second greatest cave by depth is Slovačka jama (Slovak Cave), 1320 meters in depth, with cave chanals measuring 5677 meters in total length. The third greatest cave by depth is the Cave system of Velebita, reaching down to 1026 m in depth, with the chanal length of 3176 meters (Bakšić, 2006a; 2006b). However, another 3 speleological sites, which can rightly be added to those deeper than 1000 m, have recently been discovered. These are three caverns that were discovered during construction of the Sveti Ilija Tunnel that passes through Mt. Biokovo, in the Dinaric karst area. These caverns undoubtedly point to the link with the ground surface, while the rock overburden above the tunnel in the zone where the caverns were discovered ranges from 1250 and 1350 meters. Bats from the ground surface were found in the caverns and, according to measurements, they are situated in the depth from 200 and 300 meters below the tunnel level. This would mean that the depth of these newly found caves ranges from 1450 and 1650 m, when observed from the ground surface. There are several hundreds of known caves in Biokovo, and the deepest ones discovered so far are Jama Mokre noge (Wet Feet Cave) 831 m in depth, and Jama Amfora (Amphora Cave) 788 m in depth (Bockovac, 1999; Bakšić & all, 2002; Lacković & all, 2001

  19. Microbiology and Geochemistry of Acidic Cave Biofilms in the Frasassi Caves, Italy

    NASA Astrophysics Data System (ADS)

    Meyer, K. M.; Cleaveland, L. C.; Galdenzi, S.; Macalady, J. L.

    2003-12-01

    Acidic (pH 2-4) and extremely acidic (pH 0-1) biofilms in sulfidic regions of the Frasassi cave system are relatively simple, chemoautotrophic microbial communities. As such, they serve as model systems to test relationships between microbial diversity and physical and geochemical factors. Both biofilm types are isolated from surface sources of C and N and are ultimately powered by oxidation of H2S present in the cave atmosphere. pH 2-4 biofilms consist of cells in close association with sub-um to sub-mm mineral grains (primarily CaSO4) coating cave walls. Direct counts of cells stained with 4',6-diamidino-2-phenylindole, hydrochloride (DAPI) yield a biomass estimate of 7.5 x 106 to 1.3 x 107 cells per cm3. The great majority of these cells are either dormant (contain few ribosomes) or cells which do not hybridize with either bacteria- or archaea-specific oligonucleotide probes. Sparse clusters of short rod and coccus-shaped cells hybridized with a bacteria-specific Fluorescent In Situ Hybridization (FISH) probe. Polymerase Chain Reaction (PCR) amplification of 16S rDNA was successful with bacteria-specific primers as well as with several sets of archaeal-specific primers, suggesting that some of the "dormant" cells are archaea. Extremely acidic biofilms (snottites) drip from macroscopic (1-2 cm length), reddish CaSO4 crystals on the cave walls. DAPI-staining and FISH revealed abundant bacterial rods, bacterial filaments, and fungi in the snottites. Future work will characterize the acidic cave wall biofilms, as well as neutral-pH cave stream biofilms, using 16S rDNA clone libraries in order to determine whether pH is an important factor controlling microbial diversity.

  20. Regional Similarity of Leveed Lava Flows on the Mars Plains

    NASA Technical Reports Server (NTRS)

    Baloga, Steve M.; Glaze, Lori, S.

    2008-01-01

    The dynamics of lava flow movement are controlled by the fluid interior. Crust, solids, and nondeformable material can only retard the advance or spreading of a lava flow. Figure 1 shows a typical large, channelized lava flow found on the Mars plains. It has been suggested in [I] that such large leveed flows on the Mars plains were emplaced by a balance between the formation and shedding of crust as the flow advances. For the prototypical flow north of Pavonis Mons (Fig. I), such a balance leads to a flow morphology that approximately self-replicates at all locations along the flow path [2,3]. Moreover, most quantitative characteristics of emplacement (e.g., viscosity, volumetric flow rate) of the prototype flow at Pavonis Mons resembled those of large channelized lava flows on Earth. The exception was the relatively long, sustained supply of lava, on the order of a year as opposed to hours or days for terrestrial analogs.

  1. Shallow caves and blowholes on the Nullarbor Plain, Australia — Flank margin caves on a low gradient limestone platform

    NASA Astrophysics Data System (ADS)

    Burnett, Shannon; Webb, John A.; White, Susan

    2013-11-01

    The Nullarbor Plain of southern Australia is a very extensive limestone platform with relatively few large caves for its size, but contains thousands of blowholes, sub-circular vertical shafts up to 1-2 m in diameter, which often connect to similar-sized sub-horizontal passages. Recent detailed systematic surveys of large areas of the Nullarbor Plain have provided new distribution data showing that blowholes and associated shallow caves are concentrated in a 25-30 km-wide band located > 75 km inland. The known density of these features (up to 43/25 km2) underestimates the cave porosity because the strong draughts blowing from many of the blowholes indicate that they connect to extensive cave systems of small passages. These shallow caves are relict phreatic features; their entrances (blowholes) were opened as the land surface was lowered by denudation. The band of blowholes and caves is located along the Late Miocene (~ 6 Ma) shoreline across the Nullarbor, when there was a eustatic stillstand. The caves formed in the zone of enhanced dissolution at the seaward margin of the freshwater lens along the carbonate coastline, and can therefore be regarded as flank margin caves on a low gradient limestone platform; a flank margin setting relatively unknown prior to this study. The width of the band of flank margin caves, which is substantially greater than previously documented for this cave type, reflects the very low gradient of both the ground surface and water table, together with the influence of tidal fluctuations and regression of the shoreline. Flank margin cave development stopped when the sea retreated rapidly in the Late Miocene-Early Pliocene due to a period of tilting and uplift. The band of flank margin caves has high permeability and substantial porosity, and would therefore form an excellent, largely overlooked, type of palaeokarst petroleum reservoir.

  2. The control of lava flows at Mt. Etna

    NASA Astrophysics Data System (ADS)

    Barberi, Franco; Carapezza, Maria Luisa

    Because of intense urbanization, many of the historic lava flows of Mt. Etna, fed by flank eruptions, have caused significant damage to cities, villages and lifelines. The fear of legal consequences for centuries has prevented any intervention on lava flows to reduce damage until 1983, when a lava flow was dangerously approaching a village and authorization was given. In 1983, for the first time in the world, an attempt was made to stop the flow front by diverting the lava out of its natural channel, through a breach opened by blasting the levee. The technique adopted proved very complex and thermally perturbed the lava causing overflows that prevented completion of the initial plan. Only a short partial diversion was obtained, but the desired result was however achieved as most of the lava outflowed, because of the obstruction of a nearby lava tube. The technique was improved in 1992 and a total diversion of the flow was obtained. The construction of oblique earthen barriers to divert the flows towards less damaging paths was successfully employed in 1983 and 2001. In 1992 a large earthen barrier, built orthogonally to the flow direction delayed the flow advance for nearly one month. A positive experience has been therefore acquired at Mt. Etna to protect settlements from lava flows, but some legal questions have not been yet fully solved. From the Civil Protection viewpoint, it is essential that volcanologists improve their capability of reliably assessing the distance that a lava flow may travel and whether the eruption will continue long enough for lava to reach sites of relevant socioeconomic interest.

  3. Shallow outgassing changes disrupt steady lava lake activity, Kilauea Volcano

    NASA Astrophysics Data System (ADS)

    Patrick, M. R.; Orr, T. R.; Swanson, D. A.; Lev, E.

    2015-12-01

    Persistent lava lakes are a testament to sustained magma supply and outgassing in basaltic systems, and the surface activity of lava lakes has been used to infer processes in the underlying magmatic system. At Kilauea Volcano, Hawai`i, the lava lake in Halema`uma`u Crater has been closely studied for several years with webcam imagery, geophysical, petrological and gas emission techniques. The lava lake in Halema`uma`u is now the second largest on Earth, and provides an unprecedented opportunity for detailed observations of lava lake outgassing processes. We observe that steady activity is characterized by continuous southward motion of the lake's surface and slow changes in lava level, seismic tremor and gas emissions. This normal, steady activity can be abruptly interrupted by the appearance of spattering - sometimes triggered by rockfalls - on the lake surface, which abruptly shifts the lake surface motion, lava level and gas emissions to a more variable, unstable regime. The lake commonly alternates between this a) normal, steady activity and b) unstable behavior several times per day. The spattering represents outgassing of shallowly accumulated gas in the lake. Therefore, although steady lava lake behavior at Halema`uma`u may be deeply driven by upwelling of magma, we argue that the sporadic interruptions to this behavior are the result of shallow processes occurring near the lake surface. These observations provide a cautionary note that some lava lake behavior is not representative of deep-seated processes. This behavior also highlights the complex and dynamic nature of lava lake activity.

  4. Rheological analyses of lava flows on Mars

    NASA Technical Reports Server (NTRS)

    Moore, H. J.; Davis, P. A.

    1991-01-01

    Researchers obtained 183 profiles of lava flows on Mars using photoclinometry. These photoclinometric profiles were leveled by adjusting them until the levee crests or bases had the same elevations (depending on the situation). Here, researchers report some of the results of their analysis of 27 flows on the flanks of Alba Patera (3 flows), near the summit of Ascraeus Mons (6 flows), the flanks of Arsia Mons (3 flows), and the flanks of Olympus Mons (15 flows). Results suggest that the flows examined to date are not felsic or ultramafic; rather, they probably range from basalts to basaltic andesites. Thus, the suggestion that flows on Olympus Mons and elsewhere may be more silicic than Hawaiian basalts is supported by the researchers' results. These suggestions are testable with suitable measurements of silica contents of the flows.

  5. The longevity of lava dome eruptions

    NASA Astrophysics Data System (ADS)

    Wolpert, Robert L.; Ogburn, Sarah E.; Calder, Eliza S.

    2016-02-01

    Understanding the duration of past, ongoing, and future volcanic eruptions is an important scientific goal and a key societal need. We present a new methodology for forecasting the duration of ongoing and future lava dome eruptions based on a database (DomeHaz) recently compiled by the authors. The database includes duration and composition for 177 such eruptions, with "eruption" defined as the period encompassing individual episodes of dome growth along with associated quiescent periods during which extrusion pauses but unrest continues. In a key finding, we show that probability distributions for dome eruption durations are both heavy tailed and composition dependent. We construct objective Bayesian statistical models featuring heavy-tailed Generalized Pareto distributions with composition-specific parameters to make forecasts about the durations of new and ongoing eruptions that depend on both eruption duration to date and composition. Our Bayesian predictive distributions reflect both uncertainty about model parameter values (epistemic uncertainty) and the natural variability of the geologic processes (aleatoric uncertainty). The results are illustrated by presenting likely trajectories for 14 dome-building eruptions ongoing in 2015. Full representation of the uncertainty is presented for two key eruptions, Soufriére Hills Volcano in Montserrat (10-139 years, median 35 years) and Sinabung, Indonesia (1-17 years, median 4 years). Uncertainties are high but, importantly, quantifiable. This work provides for the first time a quantitative and transferable method and rationale on which to base long-term planning decisions for lava dome-forming volcanoes, with wide potential use and transferability to forecasts of other types of eruptions and other adverse events across the geohazard spectrum.

  6. Correlation of the Deccan and Rajahmundry Trap lavas: Are these the longest and largest lava flows on Earth?

    USGS Publications Warehouse

    Self, S.; Jay, A.E.; Widdowson, M.; Keszthelyi, L.P.

    2008-01-01

    We propose that the Rajahmundry Trap lavas, found near the east coast of peninsular India, are remnants of the longest lava flows yet recognized on Earth (??? 1000??km long). These outlying Deccan-like lavas are shown to belong to the main Deccan Traps. Several previous studies have already suggested this correlation, but have not demonstrated it categorically. The exposed Rajahmundry lavas are interpreted to be the distal parts of two very-large-volume pa??hoehoe flow fields, one each from the Ambenali and Mahabaleshwar Formations of the Wai Sub-group in the Deccan Basalt Group. Eruptive conditions required to emplace such long flows are met by plausible values for cooling and eruption rates, and this is shown by applying a model for the formation of inflated pa??hoehoe sheet flow lobes. The model predicts flow lobe thicknesses similar to those observed in the Rajahmundry lavas. For the last 400??km of flow, the lava flows were confined to the pre-existing Krishna valley drainage system that existed in the basement beyond the edge of the gradually expanding Deccan lava field, allowing the flows to extend across the subcontinent to the eastern margin where they were emplaced into a littoral and/or shallow marine environment. These lavas and other individual flow fields in the Wai Sub-group may exceed eruptive volumes of 5000??km3, which would place them amongst the largest magnitude effusive eruptive units yet known. We suggest that the length of flood basalt lava flows on Earth is restricted mainly by the size of land masses and topography. In the case of the Rajahmundry lavas, the flows reached estuaries and the sea, where their advance was perhaps effectively terminated by cooling and/or disruption. However, it is only during large igneous province basaltic volcanism that such huge volumes of lava are erupted in single events, and when the magma supply rate is sufficiently high and maintained to allow the formation of very long lava flows. The Rajahmundry lava

  7. Monitoring of Radon in Tourist Part of Skocjan Caves

    NASA Astrophysics Data System (ADS)

    Debevec Gerjevic, Vanja; Jovanovic, Peter

    2010-05-01

    Due to their exceptional significance for cultural and natural heritage, the Škocjan Caves were entered on UNESCO's list of natural and cultural world heritage sites in 1986. Park Škocjan Caves is located in South Eastern part of Slovenia. It was established with aim of conserving and protecting exceptional geomorphological, geological and hydrological outstanding features, rare and endangered plant and animal species, paleontological and archaeological sites, ethnological and architectural characteristics and cultural landscape and for the purpose of ensuring opportunities for suitable development, by the National Assembly of the Republic of Slovenia in 1996. Park Škocjan Caves established monitoring that includes caves microclimate parameters: humidity, CO2, wind flow and radon concentration and daughter products. The approach in managing the working place with natural background radiation is complex. Monitoring of Radon has been functioning for more than ten years now. Presentation will show the yearly dynamic observed in the different parts of the caves, related to radon daughter products and other microclimatic data, beside the most convenient measuring technique. Implementing the Slovene legislation in the field of radiation protection, we are obligated to perform special measurements in the caves and also having our guides and workers in the caves regularly examined according to established procedure. The medical exams are performed at Institution of Occupational Safety, Ljubljana in order to monitor the influence of Radon to the workers in the cave. The equivalent dose for each employed person is also established on regular basis and it is part of medical survey of workers in the caves. The survey will be described along with education of the staff working in the caves in the field of radiation protection. An overview of Slovene legislation with practical example on implementation will be demonstrated in the case of Škocjan Caves where the managing

  8. Similarities in basalt and rhyolite lava flow emplacement processes

    NASA Astrophysics Data System (ADS)

    Magnall, Nathan; James, Mike; Tuffen, Hugh; Vye-Brown, Charlotte

    2016-04-01

    Here we use field observations of rhyolite and basalt lava flows to show similarities in flow processes that span compositionally diverse lava flows. The eruption, and subsequent emplacement, of rhyolite lava flows is currently poorly understood due to the infrequency with which rhyolite eruptions occur. In contrast, the emplacement of basaltic lava flows are much better understood due to very frequent eruptions at locations such as Mt Etna and Hawaii. The 2011-2012 eruption of Cordón Caulle in Chile enabled the first scientific observations of the emplacement of an extensive rhyolite lava flow. The 30 to 100 m thick flow infilled a topographic depression with a negligible slope angle (0 - 7°). The flow split into two main channels; the southern flow advanced 4 km while the northern flow advanced 3 km before stalling. Once the flow stalled the channels inflated and secondary flows or breakouts formed from the flow front and margins. This cooling rather than volume-limited flow behaviour is common in basaltic lava flows but had never been observed in rhyolite lava flows. We draw on fieldwork conducted at Cordón Caulle and at Mt Etna to compare the emplacement of rhyolite and basaltic flows. The fieldwork identified emplacement features that are present in both lavas, such as inflation, breakouts from the flow font and margins, and squeeze-ups on the flow surfaces. In the case of Cordón Caulle, upon extrusion of a breakout it inflates due to a combination of continued lava supply and vesicle growth. This growth leads to fracturing and breakup of the breakout surface, and in some cases a large central fracture tens of metres deep forms. In contrast, breakouts from basaltic lava flows have a greater range of morphologies depending on the properties of the material in the flows core. In the case of Mt Etna, a range of breakout morphologies are observed including: toothpaste breakouts, flows topped with bladed lava as well as breakouts of pahoehoe or a'a lava. This

  9. Monitoring of cave air temperature and humidity in the Niedźwiedzia Cave system (Sudetes, Poland) - a key to understanding tourists activity impact to cave environment

    NASA Astrophysics Data System (ADS)

    Gasiorowski, M.; Hercman, H.

    2012-04-01

    The Niedźwiedzia Cave is located in Śnieżnik Massif (the Easter Sudetes, SW Poland) at 800 m a.s.l. The length of known passages is ~3000 m and denivelation is 69 m. The system is composed of 3 levels of passages and chambers. It is a show cave with ~80,000 visitors every year. In 2010 we started monitoring program of cave air temperature and humidity, drip rate, stable isotopes and Uranium and Polonium content in water in selected sites inside the cave and in its vicinity. Changes in dropping rate in upper level are well correlated with precipitation. However, a response of dripping to rainfall depends on former precipitation frequency and intensity - during the humid period the dripping reacts immediately and after long dry period dripping responses with two-weeks delay. There is not so direct correlation between precipitation and dripping in lower level of the system. Air temperature inside the cave is almost stable in lower level (mean annual ~5.3 °C, and annual variation up to 0.7 °C) and more dynamic in the middle level (mean annual ~6.4 °C, and mean annual amplitude up to 4 °C). Daily and weekly measured changes of cave air temperature demonstrate extremely well correlation with number of visitors. In show cave passages (the middle level of the system) temperature increase 0.1-0.2 °C during every day when the cave is open for tourists and such changes is not observed during days without visitors and in lower level of the system closed for tourists. But even short visits of 3-4 cavers are recorded by temperature sensors exposed in the lower level (~0.02 °C increase). It proves very high sensitivity of cave environment to human activity. This study is funded by the National Science Centre and Higher Education grant no. N N306 131038.

  10. Packed Bed Reactor Experiment

    NASA Video Gallery

    The purpose of the Packed Bed Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed bed in reduced gravity. A packed bed consists of a metal pipe ...

  11. A geochronological approach for cave evolution in the Cantabrian Coast (Pindal Cave, NW Spain)

    USGS Publications Warehouse

    Jimenez-Sanchez, M.; Bischoff, J.L.; Stoll, H.; Aranburu, A.

    2006-01-01

    Some of the oldest speleothems in the North Cantabrian Coast (Spain) are reported for the first time in this work. Pindal Cave is developed at 24 m above sea level, in a karstic massif reaching its highest surface in a marine terrace (rasa) located at 50-64 m above the present sea level. Several phases of evolution were previously recognized into the cave, including block collapse of the roof, episodic flooding and detrital sedimentation, and chemical precipitation of at least four speleothem generations over both alluvial and collapse deposits. Three of these speleothem generations have been dated by U/Th. The first generation yielded ages from 124,2 ?? 1, 5 ka BP to 73,1 ?? 0,9 ka BP, giving a minimum age for the main detritic sediments in the cave. The second one is not dated. The third generation gives an age of 3,71 ?? 0,4 ka BP (mathematically corrected to 2.7 ?? 0.5 ka BP), while for the youngest generation, with actively growing stalagmites in the cave, basal ages of 200 years BP are estimated by counting annual laminae. The data suggest a tentative maximum elevation rate close to 0, 2 mm/yr for the Cantabrian Margin in this area, although further chronological studies will be needed to check this hypothesis. ?? 2006 Gebru??der Borntraeger.

  12. Benchmarking computational fluid dynamics models for lava flow simulation

    NASA Astrophysics Data System (ADS)

    Dietterich, Hannah; Lev, Einat; Chen, Jiangzhi

    2016-04-01

    Numerical simulations of lava flow emplacement are valuable for assessing lava flow hazards, forecasting active flows, interpreting past eruptions, and understanding the controls on lava flow behavior. Existing lava flow models vary in simplifying assumptions, physics, dimensionality, and the degree to which they have been validated against analytical solutions, experiments, and natural observations. In order to assess existing models and guide the development of new codes, we conduct a benchmarking study of computational fluid dynamics models for lava flow emplacement, including VolcFlow, OpenFOAM, FLOW-3D, and COMSOL. Using the new benchmark scenarios defined in Cordonnier et al. (Geol Soc SP, 2015) as a guide, we model viscous, cooling, and solidifying flows over horizontal and sloping surfaces, topographic obstacles, and digital elevation models of natural topography. We compare model results to analytical theory, analogue and molten basalt experiments, and measurements from natural lava flows. Overall, the models accurately simulate viscous flow with some variability in flow thickness where flows intersect obstacles. OpenFOAM, COMSOL, and FLOW-3D can each reproduce experimental measurements of cooling viscous flows, and FLOW-3D simulations with temperature-dependent rheology match results from molten basalt experiments. We can apply these models to reconstruct past lava flows in Hawai'i and Saudi Arabia using parameters assembled from morphology, textural analysis, and eruption observations as natural test cases. Our study highlights the strengths and weaknesses of each code, including accuracy and computational costs, and provides insights regarding code selection.

  13. A comparative Study of Circulation Patterns at Active Lava Lakes

    NASA Astrophysics Data System (ADS)

    Lev, Einat; Oppenheimer, Clive; Spampinato, Letizia; Hernandez, Pedro; Unglert, Kathi

    2016-04-01

    Lava lakes present a rare opportunity to study magma dynamics in a large scaled-up "crucible" and provide a unique natural laboratory to ground-truth dynamic models of magma circulation. The persistence of lava lakes allows for long-term observations of flow dynamics and of lava properties, especially compared to surface lava flows. There are currently five persistent lava lakes in the world: Halemaumau in Kilauea (Hawaii, USA), Erta Ale (Ethiopia), Nyiragongo (Congo), Erebus (Antarctica), and Villarica (Chile). Marum and Benbow craters of Ambrym volcano (Vanuatu) and Masaya (Nicaragua) have often hosted lava lakes as well. We use visible-light and thermal infrared time-lapse and video footage collected at all above lakes (except Villarica, where the lake is difficult to observe), and compare the circulation patterns recorded. We calculate lake surface motion from the footage using the optical flow method (Lev et al., 2012) to produce 2D velocity fields. We mined both the surface temperature field and the surface velocity field for patterns using machine learning techniques such as "self-organizing maps (SOMs)" and "principle component analysis (PCA)". We use automatic detection technique to study the configuration of crustal plates at the lakes' surface. We find striking differences among the lakes, in flow direction, flow speed, frequency of changes in flow direction and speed, location and consistency of upwelling and downwelling, and crustal plate configuration. We relate the differences to lake size, shallow conduit geometry, lava viscosity, crystal and gas content, and crust integrity.

  14. A burial cave in the western Aleutian Islands, Alaska.

    PubMed

    West, Dixie; Lefèvre, Christine; Corbett, Debra; Crockford, Susan

    2003-01-01

    During the 1998 field season, the Western Aleutians Archaeological and Paleobiological Project (WAAPP) team located a cave in the Near Islands, Alaska. Near the entrance of the cave, the team identified work areas and sleeping/sitting areas surrounded by cultural debris and animal bones. Human burials were found in the cave interior. In 2000, with permission from The Aleut Corporation, archaeologists revisited the site. Current research suggests three distinct occupations or uses for this cave. Aleuts buried their dead in shallow graves at the rear of the cave circa 1,200 to 800 years ago. Aleuts used the front of the cave as a temporary hunting camp as early as 390 years ago. Finally, Japanese and American military debris and graffiti reveal that the cave was visited during and after World War II. Russian trappers may have also taken shelter there 150 to 200 years ago. This is the first report of Aleut cave burials west of the Delarof Islands in the central Aleutians. PMID:21755641

  15. Guanophilic fungi in three caves of southwestern Puerto Rico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fifty species of guanophilic (bat guano-loving) fungi were isolated from field-collected samples within three caves in south-western Puerto Rico; most were mitosporic fungi (23 species). The caves studied were Cueva La Tuna (Cabo Rojo), Cueva de Malano (Sistema de Los Chorros, San Germán), and Cuev...

  16. THE MID-LATITUDE BIODIVERSITY RIDGE IN TERRESTRIAL CAVE FAUNA

    EPA Science Inventory

    The world's obligate cave-dwelling fauna holds considerable promise for biogeographic analysis because it represents a large number of independent evolutionary experiments in isolation in caves and adaptation to subterranean life. We focus on seven north temperate regions of at l...

  17. The Oldest Cave Art: An Essay on Giftedness and Excellence.

    ERIC Educational Resources Information Center

    Breen, Maureen; White, David A.

    1996-01-01

    This essay examines issues of giftedness and excellence, beginning with classical references to human striving toward the "good," the attraction of gifted children to quality, and the recent discovery of the oldest known cave art with its manifest excellence. Classroom activities related to cave art and language arts, social studies, sciences,…

  18. PROCESSES INFLUENCING VARIABILITY IN CAVE DRIP WATER TEMPERATURES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have investigated five months of epikarst storage drip water temperatures along with surface air temperature and rainfall at a small waterfall in Cave Spring Caverns, Kentucky. Falling from about 4 m, water temperatures are measured within seconds of entering the cave passage with two minute, and...

  19. Meckel's cave epidermoid with trigeminal neuralgia: CT findings.

    PubMed

    Kapila, A; Steinbaum, S; Chakeres, D W

    1984-12-01

    An epidermoid tumor of Meckel's cave was found in a middle-aged woman with trigeminal neuralgia. On CT the lesion had negative attenuation numbers of fat and extended from an expanded Meckel's cave through the porous trigeminus into the ambient and cerebellopontine angle cisterns. Surgical excision provided relief of the patient's trigeminal neuralgia. PMID:6501628

  20. Evolution and development in cave animals: from fish to crustaceans

    PubMed Central

    Protas, Meredith; Jeffery, William R.

    2013-01-01

    Cave animals are excellent models to study the general principles of evolution as well as the mechanisms of adaptation to a novel environment: the perpetual darkness of caves. In this article, two of the major model systems used to study the evolution and development (evo–devo) of cave animals are described: the teleost fish Astyanax mexicanus and the isopod crustacean Asellus aquaticus. The ways in which these animals match the major attributes expected of an evo–devo cave animal model system are described. For both species, we enumerate the regressive and constructive troglomorphic traits that have evolved during their adaptation to cave life, the developmental and genetic basis of these traits, the possible evolutionary forces responsible for them, and potential new areas in which these model systems could be used for further exploration of the evolution of cave animals. Furthermore, we compare the two model cave animals to investigate the mechanisms of troglomorphic evolution. Finally, we propose a few other cave animal systems that would be suitable for development as additional models to obtain a more comprehensive understanding of the developmental and genetic mechanisms involved in troglomorphic evolution. PMID:23580903

  1. Reconstructing western Grand Canyon's lava dams and their failure mechanisms: new insights from geochemical correlation and 40Ar/39Ar dating

    NASA Astrophysics Data System (ADS)

    Crow, R.; Karlstrom, K. E.; McIntosh, W. C.; Peters, L.; Dunbar, N. W.

    2010-12-01

    longer lived because they undergo less interaction with river water and fracturing and generally fill dry portions of the river bed. Identification of far-traveled clasts on top of lava dam remnants in at least two locations supports the idea that the stable Colorado River established itself on top of the distal parts of some lava dams. Thus, whereas previous workers reported that deposits from outburst flood dam failure events exist in western grand canyon, our data identify specific dam failures and an interaction of catastrophic events at the head of lava dams and modified fluvial processes in distal portions of dams.

  2. Improvement of a 2D numerical model of lava flows

    NASA Astrophysics Data System (ADS)

    Ishimine, Y.

    2013-12-01

    I propose an improved procedure that reduces an improper dependence of lava flow directions on the orientation of Digital Elevation Model (DEM) in two-dimensional simulations based on Ishihara et al. (in Lava Flows and Domes, Fink, JH eds., 1990). The numerical model for lava flow simulations proposed by Ishihara et al. (1990) is based on two-dimensional shallow water model combined with a constitutive equation for a Bingham fluid. It is simple but useful because it properly reproduces distributions of actual lava flows. Thus, it has been regarded as one of pioneer work of numerical simulations of lava flows and it is still now widely used in practical hazard prediction map for civil defense officials in Japan. However, the model include an improper dependence of lava flow directions on the orientation of DEM because the model separately assigns the condition for the lava flow to stop due to yield stress for each of two orthogonal axes of rectangular calculating grid based on DEM. This procedure brings a diamond-shaped distribution as shown in Fig. 1 when calculating a lava flow supplied from a point source on a virtual flat plane although the distribution should be circle-shaped. To improve the drawback, I proposed a modified procedure that uses the absolute value of yield stress derived from both components of two orthogonal directions of the slope steepness to assign the condition for lava flows to stop. This brings a better result as shown in Fig. 2. Fig. 1. (a) Contour plots calculated with the original model of Ishihara et al. (1990). (b) Contour plots calculated with a proposed model.

  3. Numerical simulation of lava flows: Applications to the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Zimbelman, James R.; Campbell, Bruce A.; Kousoum, Juliana; Lampkin, Derrick J.

    1993-01-01

    Lava flows are the visible expression of the extrusion of volcanic materials on a variety of planetary surfaces. A computer program described by Ishihara et al. appears to be well suited for application to different environments, and we have undertaken tests to evaluate their approach. Our results are somewhat mixed; the program does reproduce reasonable lava flow behavior in many situations, but we have encountered some conditions common to planetary environments for which the current program is inadequate. Here we present our initial efforts to identify the 'parameter space' for reasonable numerical simulations of lava flows.

  4. Comparative analysis between Payen and Daedalia Planum lava fields

    NASA Astrophysics Data System (ADS)

    Giacomini, Lorenza; Massironi, Matteo; Pasquarè, Giorgio; Carli, Cristian; Martellato, Elena; Frigeri, Alessandro; Cremonese, Gabriele; Bistacchi, Andrea; Federico, Costanzo

    The Payen volcanic complex is a large Quaternary fissural structure belonging to the back-arc extensional area of the Andes in the Mendoza Province (Argentina). From the eastern portion of this volcanic structure huge pahoehoe lava flows were emitted, extending more than 180 km from the feeding vents. These huge flows propagated over the nearly flat surface of the Pampean foreland (ca 0.3° slope). The very low viscosity of the olivine basalt lavas, coupled with the inflation process are the most probable explanation for their considerable length. In an inflation process a thin viscoelastic crust, produced at an early stage, is later inflated by the underlying fluid core, which remains hot and fluid thanks to the thermal-shield effect of the crust. The inflation shows some typical morphological fingerprints like tumuli, lava lobes, lava rises and lava ridges. In order to compare the morphology of the Argentinean Payen flows with lava flows on Mars, MOLA, THEMIS, MOC, MRO/HIRISE, and MEX/OMEGA data have been analysed, providing a multi-scale characterisation of Martian flows. Mars Global Surveyor/MOLA data were used to investigate the topographic environment over which flows propagated on Mars in order to detect very low angle slopes where possibly inflation processes could have developed. Then Mars Odyssey/THEMIS and Mars Global Surveyor's MOC data were used to detect Martian lava flows with inflation "fingerprints", whereas OMEGA data were used to obtain some inferences about their composition. Finally the MRO/HIRISE images recently acquired, can provide further details and constraints on surface morphologies and lava fronts. All these data were used to analyze Daedalia Planum lava field, at about 300 km southwest of Arsia Mons, and clear morphological similarities with the longest flows of the Payen lava fields were found. These striking morphological analogies suggest that inflation process is quite common also for the Daedalia field. This is also supported by

  5. Numerical simulation of lava flows: Applications to the terrestrial planets

    NASA Astrophysics Data System (ADS)

    Zimbelman, James R.; Campbell, Bruce A.; Kousoum, Juliana; Lampkin, Derrick J.

    1993-03-01

    Lava flows are the visible expression of the extrusion of volcanic materials on a variety of planetary surfaces. A computer program described by Ishihara et al. appears to be well suited for application to different environments, and we have undertaken tests to evaluate their approach. Our results are somewhat mixed; the program does reproduce reasonable lava flow behavior in many situations, but we have encountered some conditions common to planetary environments for which the current program is inadequate. Here we present our initial efforts to identify the 'parameter space' for reasonable numerical simulations of lava flows.

  6. Map Showing Lava Inundation Zones for Mauna Loa, Hawaii

    USGS Publications Warehouse

    Trusdell, F.A.; Graves, P.; Tincher, C.R.

    2002-01-01

    Introduction The Island of Hawaii is composed of five coalesced basaltic volcanoes. Lava flows constitute the greatest volcanic hazard from these volcanoes. This report is concerned with lava flow hazards on Mauna Loa, the largest of the island shield volcanoes. Hilo lies 58 km from the summit of Mauna Loa, the Kona coast 33 km, and the southernmost point of the island 61 km. Hawaiian volcanoes erupt two morphologically distinct types of lava, aa and pahoehoe. The surfaces of pahoehoe flows are rather smooth and undulating. Pahoehoe flows are commonly fed by lava tubes, which are well insulated, lava-filled conduits contained within the flows. The surfaces of aa flows are extremely rough and composed of lava fragments. Aa flows usually form lava channels rather than lava tubes. In Hawaii, lava flows are known to reach distances of 50 km or more. The flows usually advance slowly enough that people can escape from their paths. Anything overwhelmed by a flow will be damaged or destroyed by burial, crushing, or ignition. Mauna Loa makes up 51 percent of the surface area of the Island of Hawaii. Geologic mapping shows that lava flows have covered more than 40 percent of the surface every 1,000 years. Since written descriptions of its activity began in A.D. 1832, Mauna Loa has erupted 33 times. Some eruptions begin with only brief seismic unrest, whereas others start several months to a year following increased seismic activity. Once underway, the eruptions can produce lava flows that reach the sea in less than 24 hours, severing roads and utilities. For example, the 1950 flows from the southwest rift zone reached the ocean in approximately three hours. The two longest flows of Mauna Loa are pahoehoe flows from the 50-kilometer-long 1859 and the 48-kilometer-long 1880-81 eruptions. Mauna Loa will undoubtedly erupt again. When it does, the first critical question that must be answered is: Which areas are threatened with inundation? Once the threatened areas are

  7. Modelling the thermal effects of spherulite growth in rhyolitic lava

    NASA Astrophysics Data System (ADS)

    Tuffen, H.; Cordonnier, B.; Castro, J. M.

    2012-12-01

    Rhyolitic lava flows, sills and dykes commonly comprise a spherulitic interior enveloped by a glassy carapace. Spherulite crystallisation has long been assumed to be a "passive" process that occurs during cooling of the lava around and below its glass transition temperature (~600-700 °C). It has also been suggested to be self-limiting due to diffusion controlled growth, creating only a small proportion of spherulites embedded in glass (snowflake obsidian). However, textures in rhyolitic lava bodies at Hrafntinnuhryggur, Krafla, Iceland indicate that near-complete spherulite crystallisation can occur, and suggest that parts of the lava spatially associated with zones of spherulite and lithophysae growth may be significantly heated. Evidence for heating includes melting of parts of the glassy lava carapace by lower-viscosity, invading melt of identical composition. Additionally, spherulitic crystal morphologies have been grown experimentally at undercoolings of only 100 °C. As the liquidus temperature of dry rhyolite may approach 1200 °C, this means that spherulites could continue to grow in degassed magma at temperatures of >900 °C, well above the initial magma temperature. We use new constraints on spherulite growth rates to model the thermal effects of spherulite growth within rhyolitic lava bodies, using three growth laws (size- and temperature-dependent, diffusion controlled and linear) and a variety of initial temperatures, nucleation densities and seed nuclei sizes. Models consider both latent heat release due to crystallisation and conductive cooling. Model results indicate that, when lava bodies are sufficiently large, spherulite growth can cause considerable heating (possibly >150 °C), enabling parts of lava bodies to heat to above the initial eruption temperature. This heating can lead to a viscosity reduction of orders of magnitude and trigger vesiculation. Model results indicate that cooling rates of between 10-3 to 10-5 °C/s ought to mark the

  8. Thick seam sub-level caving with new Hungarian shield

    SciTech Connect

    Pera, F.

    1983-08-01

    Sub-level caving has been introduced in a longwall face at Akja Colliery, Hungary. Upper seams have been mined previously by room and pillar methods, having pillars. The limestone roof has been broken up by the earlier mining operations and continues to fracture. Portions of the remaining coal pillars and the lower seams are fissured. Thus the roof rock and coal can be properly caved. Experience showed that a sub-level caving shield was required, and a caliper-shield type support was developed. The design is described and details are given of its operation. The shield contains a caving door enabling the caved coal to be directed onto the armoured face conveyor. The support system has operated satisfactorily since August 1982.

  9. Numerical and Experimental Approaches Toward Understanding Lava Flow Heat Transfer

    NASA Astrophysics Data System (ADS)

    Rumpf, M.; Fagents, S. A.; Hamilton, C.; Crawford, I. A.

    2013-12-01

    We have performed numerical modeling and experimental studies to quantify the heat transfer from a lava flow into an underlying particulate substrate. This project was initially motivated by a desire to understand the transfer of heat from a lava flow into the lunar regolith. Ancient regolith deposits that have been protected by a lava flow may contain ancient solar wind, solar flare, and galactic cosmic ray products that can give insight into the history of our solar system, provided the records were not heated and destroyed by the overlying lava flow. In addition, lava-substrate interaction is an important aspect of lava fluid dynamics that requires consideration in lava emplacement models Our numerical model determines the depth to which the heat pulse will penetrate beneath a lava flow into the underlying substrate. Rigorous treatment of the temperature dependence of lava and substrate thermal conductivity and specific heat capacity, density, and latent heat release are imperative to an accurate model. Experiments were conducted to verify the numerical model. Experimental containers with interior dimensions of 20 x 20 x 25 cm were constructed from 1 inch thick calcium silicate sheeting. For initial experiments, boxes were packed with lunar regolith simulant (GSC-1) to a depth of 15 cm with thermocouples embedded at regular intervals. Basalt collected at Kilauea Volcano, HI, was melted in a gas forge and poured directly onto the simulant. Initial lava temperatures ranged from ~1200 to 1300 °C. The system was allowed to cool while internal temperatures were monitored by a thermocouple array and external temperatures were monitored by a Forward Looking Infrared (FLIR) video camera. Numerical simulations of the experiments elucidate the details of lava latent heat release and constrain the temperature-dependence of the thermal conductivity of the particulate substrate. The temperature-dependence of thermal conductivity of particulate material is not well known

  10. Hardened Lava Meets Wind on Mars

    NASA Technical Reports Server (NTRS)

    2006-01-01

    NASA's Mars Exploration Rover Spirit used its microscopic imager to capture this spectacular, jagged mini-landscape on a rock called 'GongGong.' Measuring only 3 centimeters (1.2 inches) across, this surface records two of the most important and violent forces in the history of Mars -- volcanoes and wind.

    GongGong formed billions of years ago in a seething, stirring mass of molten rock. It captured bubbles of gases that were trapped at great depth but had separated from the main body of lava as it rose to the surface. Like taffy being stretched and tumbled, the molten rock was deformed as it moved across an ancient Martian landscape. The tiny bubbles of gas were deformed as well, becoming elongated. When the molten lava solidified, the rock looked like a frozen sponge.

    Far from finished with its life, the rock then withstood billions of years of pelting by small sand grains carried by Martian dust storms that sometimes blanketed the planet. The sand wore away the surface until, little by little, the delicate strands that enclosed the bubbles of gas were breached and the spiny texture we see today emerged.

    Even now, wind continues to deposit sand and dust in the holes and crevices of the rock.

    Similar rocks can be found on Earth where the same complex interplay of volcanoes and weathering occur, whether it be the pelting of rocks by sand grains in the Mojave desert or by ice crystals in the frigid Antarctic.

    GongGong is one of a group of rocks studied by Spirit and informally named by the Athena Science Team to honor the Chinese New Year (the Year of the Dog). In Chinese mythology, GongGong was the god-king of water in the North Land. When he sacrificed his life to knock down Mount BuZhou, he defeated the bad Emperor in Heaven, freed the sun, moon and stars to go from east to west, and caused all the rivers in China to flow from west to east.

    Spirit's microscopic imager took this image during on the rover's 736th day, or sol, of

  11. Fossil invertebrates records in cave sediments and paleoenvironmental assessments: a study of four cave sites from Romanian Carpathians

    NASA Astrophysics Data System (ADS)

    Moldovan, O. T.; Constantin, S.; Panaiotu, C.; Roban, R. D.; Frenzel, P.; Miko, L.

    2015-06-01

    Fossil invertebrates from cave sediments have been recently described as a potential new proxy for paleoenvironment and used in cross-correlations with alternate proxy records from cave deposits. Here we present the results of a fossil invertebrates study in four caves from two climatically different regions of the Romanian Carpathians, to complement paleoenvironmental data previously reported. Oribatid mites and ostracods are the most common invertebrates in the studied cave sediments. Some of the identified taxa are new for science, and most of them are indicative for either warm/cold stages or dry/wetter oscillations. In two caves the fossil invertebrates records indicate rapid climate oscillations during times known for a relatively stable climate. By corroborating the fossil invertebrates' record with the information given by magnetic properties and sediment structures, complementary data on past vegetation, temperatures, and hydraulic regimes could be gathered. This paper analyses the potential of fossil invertebrate records as a paleoenvironmental proxy, potential problems and pitfalls.

  12. 43 CFR 37.11 - Nomination, evaluation, and designation of significant caves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Nomination, evaluation, and designation of significant caves. 37.11 Section 37.11 Public Lands: Interior Office of the Secretary of the Interior CAVE MANAGEMENT Cave Designation § 37.11 Nomination, evaluation, and designation of significant caves. (a) Nominations for initial and...

  13. OBLIQUE VIEW OF THE NORTHWEST SIDE. NOTE THE LAVA ROCK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OBLIQUE VIEW OF THE NORTHWEST SIDE. NOTE THE LAVA ROCK FOUNDATION PIERS AND DETAILING AT THE WINDOWS. VIEW FACING SOUTHWEST. - Hickam Field, Fort Kamehameha Officers' Housing Type Z, 19 Worchester Avenue, Honolulu, Honolulu County, HI

  14. DETAIL OF LAVA BEDROCK WHICH WILL ACT AS BASE SUPPORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF LAVA BEDROCK WHICH WILL ACT AS BASE SUPPORT FOR REACTOR. INL NEGATIVE NO. 472. Unknown Photographer, 8/23/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  15. Athabasca Valles, Mars: A lava-draped channel system

    USGS Publications Warehouse

    Jaeger, W.L.; Keszthelyi, L.P.; McEwen, A.S.; Dundas, C.M.; Russell, P.S.

    2007-01-01

    Athabasca Valles is a young outflow channel system on Mars that may have been carved by catastrophic water floods. However, images acquired by the High-Resolution Imaging Science Experiment camera onboard the Mars Reconnaissance Orbiter spacecraft reveal that Athabasca Valles is now entirely draped by a thin layer of solidified lava - the remnant of a once-swollen river of molten rock. The lava erupted from a fissure, inundated the channels, and drained downstream in geologically recent times. Purported ice features in Athabasca Valles and its distal basin, Cerberus Palus, are actually composed of this lava. Similar volcanic processes may have operated in other ostensibly fluvial channels, which could explain in part why the landers sent to investigate sites of ancient flooding on Mars have predominantly found lava at the surface instead.

  16. Detail of redwood tank on lava rock platform. Trestle and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail of redwood tank on lava rock platform. Trestle and steel tanks can be see in right background. - Hawaii Volcanoes National Park Water Collection System, Hawaii Volcanoes National Park, Volcano, Hawaii County, HI

  17. Arsia Mons Lava Flows at Night

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    This nighttime IR image is of lava flows from Arsia Mons. The different tones of brightness in the nighttime IR are indicative of the relative ages of the flows in the images. The small circular features are impact craters.

    Image information: IR instrument. Latitude -5.7, Longitude 243.5 East (116.5 West). 100 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. Soft-bottom crustacean assemblages in Mediterranean marine caves: the cave of Cerro Gordo (Granada, Spain) as case study

    NASA Astrophysics Data System (ADS)

    Navarro-Barranco, C.; Guerra-García, J. M.; Sánchez-Tocino, L.; García-Gómez, J. C.

    2012-12-01

    Although marine caves are priority conservation areas according to the Directive 92/43/CEE of the European Community, there is a lack of studies dealing with their soft-bottom communities. For a case study, we selected the Cerro Gordo cave at 15 m depth. Three different zones were defined: a semi-dark 25-m long entrance area, a dark intermediate area of 35 m, and the final zone at 90 m from the entrance. Sediment samples were taken from these zones as well as from outside the cave (control) by SCUBA diving. Six rectangular cores of 10 × 250 cm2 were collected in each site for macrofaunal study, and three more replicates were taken to analyze physico-chemical parameters. The granulometry showed a clear gradient from medium sands outside the cave to silt and clay in the inner zone. Measurements of the crustacean assemblages showed that the number of species and abundance were significantly higher outside the cave (30-40 species, >4,000 ind m-2) than inside (5-10 species, <1,000 ind m-2). Multivariate analyses showed a clear difference in species composition between outside and inside the cave. Caprellids, tanaids, cumaceans, and decapods were only found outside the cave, while gammarids and isopods were present both outside and inside the cave. The gammarid Siphonoecetes sabatieri and the tanaid Apseudes latreilli were the dominant species outside the cave, while the gammarids Harpinia pectinata, Harpinia crenulata, and Harpinia ala were dominant inside. The present study represents an increase in depth range and geographic distribution for Kupellonura mediterranea and Monoculodes packardi. This is the first description of soft-bottom crustacean communities from submarine caves of southern Spain.

  19. Seven Possible Cave Skylights on Mars

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1

    Seven very dark holes on the north slope of a Martian volcano have been proposed as possible cave skylights, based on day-night temperature patterns suggesting they are openings to subsurface spaces. These six excerpts of images taken in visible-wavelength light by the Thermal Emission Imaging System camera on NASA's Mars Odyssey orbiter show the seven openings. Solar illumination comes from the left in each frame. The volcano is Arsia Mons, at 9 degrees south latitude, 239 degrees east longitude.

    The features have been given informal names to aid comparative discussion (see figure 1). They range in diameter from about 100 meters (328 feet) to about 225 meters (738 feet). The candidate cave skylights are (A) 'Dena,' (B) 'Chloe,' (C) 'Wendy,' (D) 'Annie,' (E) 'Abby' (left) and 'Nikki,' and (F) 'Jeanne.' Arrows signify north and the direction of illumination.

    Mars Odyssey is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The orbiter's Thermal Emission Imaging System was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing, Santa Barbara, Calif., and is operated by Arizona State University.

  20. Automated Search for Lunar Lava Tubes in the Clementine Dataset

    NASA Astrophysics Data System (ADS)

    Taylor, Allen G.; Gibbs, A.

    1998-01-01

    A significant problem in computer science, which has become increasingly acute recently, is the automatic extraction and cataloging of desired features from large sets of complex images. Solution of this problem could potentially have broad applicability. As a prototype of this kind of problem, our group has chosen to attempt the automatic retrieval of lava tubes from the Clementine dataset. Lunar lava tubes have long been recognized as desirable locations for the placement of manned lunar bases. Advantages include that (1) little construction is needed; (2) building materials need not be lifted out of Earth's gravity well; (3) the tubes provide natural environmental control; and (4) the tubes provide natural protection from cosmic rays, meteorites, micrometeorites, and impact crater ejecta. Coombs and Hawke identified about 100 probable lava tubes associated with sinuous rilles in the Lunar Orbiter and Apollo photos, primarily in the nearside maria. The lava tubes that are visible to Earth-based telescopes might be too large to provide good candidates for lunar bases. Such lava tubes of large diameter need a great depth of overlying rock to keep from collapsing. Any intact large tubes would lie inconveniently far underground. Most useful would be lava tubes that are too small to be discerned from Earth. The Clementine spacecraft, which mapped the entire surface of the Moon to an unprecedented level of detail in 1994, gives us a view of these smaller lava tubes. Over 1.9 million images in the visible, near infrared, and mid-infrared portions of the spectrum were captured. Our task is to find and catalog the small lava tubes in the Clementine dataset. Of particular interest are small sinuous rifles that contain interruptions, which represent uncollapsed portions of a tube that has partially collapsed. Once cataloged, the candidate base locations can be examined more closely for suitability. Considerations would be proximity to resources, sites of scientific interest

  1. Clinker formation in basaltic and trachybasaltic lava flows

    NASA Astrophysics Data System (ADS)

    Loock, Sébastien; van Wyk de Vries, Benjamin; Hénot, Jean-Marc

    2010-09-01

    Clinker is a term used to describe massive or scoriaceous fragments commonly associated with ‘a‘ā lava flows. Clinker is generally considered to form by fragmentation of an upper vesiculated crust, due to an increase in apparent viscosity and/or to an increase in shear strain rate. Surface clinker is considered to be transported to the flow front and incorporated at the base by caterpillar motion. Clinker that we have observed on a variety of lava flows has very variable textures, which suggests several different mechanisms of formation. In order to study clinker formation, we examined several lava flows from the Chaîne des Puys Central France, where good sections, surface morphology and surface textures are widespread and clearly visible. We observed basal and surface ‘a‘ā clinker that has fragmentation textures similar to those observed in ash formed in eruptions under dry conditions. In two pāhoehoe flows we have observed basal clinker that formed in-situ. Two other flows display clinker features identical to those commonly observed in phreatomagmatic ash, such as adhering particles, blocky shapes, spherical glass and attached microphenocrysts. Another pāhoehoe flow has a flakey, angular basal breccia, with microfaulted and abraded clasts. These were probably formed at a cooled lava base by large amounts of simple shear and consequent intra-lava brittle faulting. Using these observations we propose three different ways of fragmentation. (1) Clinker can form at the surface and eventually produce roll-over basal breccia. (2) Water/lava interactions can form basal clinker by phreatomagmatic fragmentation. Water/lava ratio variations may produce different clinker structures, in a manner similar to observed textural changes in phreatomagmatic eruptions. (3) Clinker can be formed by brittle brecciation during basal simple shear. The different clinker can provide information about the mechanisms and environmental conditions during lava flow emplacement.

  2. Validating Cellular Automata Lava Flow Emplacement Algorithms with Standard Benchmarks

    NASA Astrophysics Data System (ADS)

    Richardson, J. A.; Connor, L.; Charbonnier, S. J.; Connor, C.; Gallant, E.

    2015-12-01

    A major existing need in assessing lava flow simulators is a common set of validation benchmark tests. We propose three levels of benchmarks which test model output against increasingly complex standards. First, imulated lava flows should be morphologically identical, given changes in parameter space that should be inconsequential, such as slope direction. Second, lava flows simulated in simple parameter spaces can be tested against analytical solutions or empirical relationships seen in Bingham fluids. For instance, a lava flow simulated on a flat surface should produce a circular outline. Third, lava flows simulated over real world topography can be compared to recent real world lava flows, such as those at Tolbachik, Russia, and Fogo, Cape Verde. Success or failure of emplacement algorithms in these validation benchmarks can be determined using a Bayesian approach, which directly tests the ability of an emplacement algorithm to correctly forecast lava inundation. Here we focus on two posterior metrics, P(A|B) and P(¬A|¬B), which describe the positive and negative predictive value of flow algorithms. This is an improvement on less direct statistics such as model sensitivity and the Jaccard fitness coefficient. We have performed these validation benchmarks on a new, modular lava flow emplacement simulator that we have developed. This simulator, which we call MOLASSES, follows a Cellular Automata (CA) method. The code is developed in several interchangeable modules, which enables quick modification of the distribution algorithm from cell locations to their neighbors. By assessing several different distribution schemes with the benchmark tests, we have improved the performance of MOLASSES to correctly match early stages of the 2012-3 Tolbachik Flow, Kamchakta Russia, to 80%. We also can evaluate model performance given uncertain input parameters using a Monte Carlo setup. This illuminates sensitivity to model uncertainty.

  3. A review: Quantitative models for lava flows on Mars

    NASA Technical Reports Server (NTRS)

    Baloga, S. M.

    1987-01-01

    The purpose of this abstract is to review and assess the application of quantitative models (Gratz numerical correlation model, radiative loss model, yield stress model, surface structure model, and kinematic wave model) of lava flows on Mars. These theoretical models were applied to Martian flow data to aid in establishing the composition of the lava or to determine other eruption conditions such as eruption rate or duration.

  4. Lava flow rheology: A comparison of morphological and petrological methods

    NASA Astrophysics Data System (ADS)

    Chevrel, M. O.; Platz, T.; Hauber, E.; Baratoux, D.; Lavallée, Y.; Dingwell, D. B.

    2013-12-01

    In planetary sciences, the emplacement of lava flows is commonly modelled using a single rheological parameter (apparent viscosity or apparent yield strength) calculated from morphological dimensions using Jeffreys' and Hulme's equations. The rheological parameter is then typically further interpreted in terms of the nature and chemical composition of the lava (e.g., mafic or felsic). Without the possibility of direct sampling of the erupted material, the validity of this approach has remained largely untested. In modern volcanology, the complex rheological behaviour of lavas is measured and modelled as a function of chemical composition of the liquid phase, fractions of crystals and bubbles, temperature and strain rate. Here, we test the planetary approach using a terrestrial basaltic lava flow from the Western Volcanic Zone in Iceland. The geometric parameters required to employ Jeffreys' and Hulme's equations are accurately estimated from high-resolution HRSC-AX Digital Elevation Models. Samples collected along the lava flow are used to constrain a detailed model of the transient rheology as a function of cooling, crystallisation, and compositional evolution of the residual melt during emplacement. We observe that the viscosity derived from the morphology corresponds to the value estimated when significant crystallisation inhibits viscous deformation, causing the flow to halt. As a consequence, the inferred viscosity is highly dependent on the details of the crystallisation sequence and crystal shapes, and as such, is neither uniquely nor simply related to the bulk chemical composition of the erupted material. This conclusion, drawn for a mafic lava flow where crystallisation is the primary process responsible for the increase of the viscosity during emplacement, should apply to most of martian, lunar, or mercurian volcanic landforms, which are dominated by basaltic compositions. However, it may not apply to felsic lavas where vitrification resulting from

  5. Studies of vesicle distribution patterns in Hawaiian lavas

    NASA Technical Reports Server (NTRS)

    Walker, George P. L.

    1987-01-01

    Basaltic lava flows are generally vesicular, and the broader facts relating to vesicle distribution have long been established; few studies have yet been made with a view to determining how and when vesicles form in the cooling history of the lava, explaining vesicle shape and size distribution, and gaining enough understanding to employ vesicles as a geological tool. Various avenues of approach exist by which one may seek to gain a better understanding of these ubiquitous structures and make a start towards developing a general theory, and three such avenues have recently been explored. One avenue involves the study of pipe vesicles; these are a well known feature of lava flows and are narrow pipes which occur near the base of many pahoehoe flow units. Another avenue of approach is that presented by the distinctive spongy pahoehoe facies of lava that is common in distal locations on Hawaiian volcanoes. A third avenue of approach is that of the study of gas blisters in lava. Gas blisters are voids, which can be as much as tens of meters wide, where the lava split along a vesicle-rich layer and the roof up-arched by gas pressure. These three avenues are briefly discussed.

  6. Stochastic modeling of a lava-flow aquifer system

    USGS Publications Warehouse

    Cronkite-Ratcliff, Collin; Phelps, Geoffrey A.

    2014-01-01

    This report describes preliminary three-dimensional geostatistical modeling of a lava-flow aquifer system using a multiple-point geostatistical model. The purpose of this study is to provide a proof-of-concept for this modeling approach. An example of the method is demonstrated using a subset of borehole geologic data and aquifer test data from a portion of the Calico Hills Formation, a lava-flow aquifer system that partially underlies Pahute Mesa, Nevada. Groundwater movement in this aquifer system is assumed to be controlled by the spatial distribution of two geologic units—rhyolite lava flows and zeolitized tuffs. The configuration of subsurface lava flows and tuffs is largely unknown because of limited data. The spatial configuration of the lava flows and tuffs is modeled by using a multiple-point geostatistical simulation algorithm that generates a large number of alternative realizations, each honoring the available geologic data and drawn from a geologic conceptual model of the lava-flow aquifer system as represented by a training image. In order to demonstrate how results from the geostatistical model could be analyzed in terms of available hydrologic data, a numerical simulation of part of an aquifer test was applied to the realizations of the geostatistical model.

  7. Effect of a fluctuating supply on lava flow emplacement

    NASA Astrophysics Data System (ADS)

    Tarquini, S.; De'Michieli Vitturi, M.

    2013-12-01

    The evolution of lava flows emplaced at Mount Etna (Italy) in September 2004 is examined in detail through the analysis of morphometric measurements of flow units. The collected layout of data suggests that the growth of the main channelized flow unit is consistent with a layering of lava blankets which maintains the initial geometry of the channel, although levees are widened and raised. The growth of the flow unit is here related to the overflow of lava pulses which have already been described for the considered lava flows. A simple analytical model describing the evolution of the lava level in a channelized flow unit fed by a fluctuating supply is introduced. The model shows that a fluctuation in the velocity of extrusion of lava at the vent triggers the formation of pulses which become increasingly high with distance from the vent, and are destined to overflow within a given distance. Our results cope well with the observed morphology, characterized by a very flat initial profile followed by a massive increase in flow unit section area between 600 and 700 m downflow from the vent. The inferred emplacement dynamics provides also an explanation for the observed substantial 'loss' of the original flowing mass with increasing distance from the vent.

  8. Origins and implications of zigzag rift patterns on lava lakes

    NASA Astrophysics Data System (ADS)

    Karlstrom, Leif; Manga, Michael

    2006-06-01

    The distinctive rift patterns observed on newly formed lava lakes are very likely a product of interaction between heat transfer (cooling of lava) and deformation of the solid crust in response to applied stresses. One common pattern consists of symmetric "zigzag" rifts separating spreading plates. Zigzags can be characterized by two measurable parameters: an amplitude A, and an angle θ between segments that make up the zigzags. Similar patterns are observed in analog wax experiments in which molten wax acts as cooling and solidifying lava. We perform a series of these wax experiments to find the relationship between θ, A, and the cooling rate. We develop a model to explain the observed relationships: θ is determined by a balance of spreading and solidification speeds; the amplitude A is limited by the thickness of the solid wax crust. Theoretical predictions agree well with experimental data; this enables us to scale the model to basaltic lava lakes. If zigzag rifts are observed on the surface of lava lakes, and if physical properties of the lava crust can be measured or inferred by other means, measurements of θ and A make it possible to calculate crust-spreading velocity and crust thickness.

  9. Discrimination, correlation, and provenance of Bed I tephrostratigraphic markers, Olduvai Gorge, Tanzania, based on multivariate analyses of phenocryst compositions

    NASA Astrophysics Data System (ADS)

    Habermann, Jörg M.; McHenry, Lindsay J.; Stollhofen, Harald; Tolosana-Delgado, Raimon; Stanistreet, Ian G.; Deino, Alan L.

    2016-06-01

    The chronology of Pleistocene flora and fauna, including hominin remains and associated Oldowan industries in Bed I, Olduvai Gorge, Tanzania, is primarily based on 40Ar/39Ar dating of intercalated tuffs and lavas, combined with detailed tephrostratigraphic correlations within the basin. Although a high-resolution chronostratigraphic framework has been established for the eastern part of the Olduvai Basin, the western subbasin is less well known due in part to major lateral facies changes within Bed I combined with discontinuous exposure. We address these correlation difficulties using the discriminative power of the chemical composition of the major juvenile mineral phases (augite, anorthoclase, plagioclase) from tuffs, volcaniclastic sandstones, siliciclastic units, and lavas. We statistically evaluate these compositions, obtained from electron probe micro-analysis, applying principal component analysis and discriminant analysis to develop discriminant models that successfully classify most Bed I volcanic units. The correlations, resulting from integrated analyses of all target minerals, provide a basin-wide Bed I chemostratigraphic framework at high lateral and vertical resolution, consistent with the known geological context, that expands and refines the geochemical databases currently available. Correlation of proximal ignimbrites at the First Fault with medial and distal Lower Bed I successions of the western basin enables assessment of lateral facies and thickness trends that confirm Ngorongoro Volcano as the primary source for Lower Bed I, whereas Upper Bed I sediment supply is mainly from Olmoti Volcano. Compositional similarity between Tuff IA, Bed I lava, and Mafic Tuffs II and III single-grain fingerprints, together with north- and northwestward thinning of Bed I lava, suggests a common Ngorongoro source for these units. The techniques applied herein improve upon previous work by evaluating compositional affinities with statistical rigor rather than

  10. Vision-mediated interaction with the Nottingham caves

    NASA Astrophysics Data System (ADS)

    Ghali, Ahmed; Bayomi, Sahar; Green, Jonathan; Pridmore, Tony; Benford, Steve

    2003-05-01

    The English city of Nottingham is widely known for its rich history and compelling folklore. A key attraction is the extensive system of caves to be found beneath Nottingham Castle. Regular guided tours are made of the Nottingham caves, during which castle staff tell stories and explain historical events to small groups of visitors while pointing out relevant cave locations and features. The work reported here is part of a project aimed at enhancing the experience of cave visitors, and providing flexible storytelling tools to their guides, by developing machine vision systems capable of identifying specific actions of guides and/or visitors and triggering audio and/or video presentations as a result. Attention is currently focused on triggering audio material by directing the beam of a standard domestic flashlight towards features of interest on the cave wall. Cameras attached to the walls or roof provide image sequences within which torch light and cave features are detected and their relative positions estimated. When a target feature is illuminated the corresponding audio response is generated. We describe the architecture of the system, its implementation within the caves and the results of initial evaluations carried out with castle guides and members of the public.

  11. Geoarchaeological study of Katarraktes cave system - a geochemical approach

    NASA Astrophysics Data System (ADS)

    Psomiadis, D.; Dotsika, E.; Albanakis, K.; Pennos, C.; Zisi, N.; Syros, A.; Vaxevanopoulos, M.; Pehlivanidou, S.

    2009-04-01

    Archaeological excavations in the cave system of Katarraktes, near Sidirokastro, Macedonia, Greece, begun in 2004 and brought into surface a great number of historical and prehistoric findings. The setting of the archaeological studies was mainly a rock-roof and the findings aged from Bronze Age till modern times. The main activity of that location seemed to be food preparation and storage. In order to investigate the correlation between human use of the cave and the environmental conditions of the area during those parts of prehistoric and historical time, a geochemical study was conducted, dealing with waters of the cave system, cave unconsolidated sediments and carbonate rocky depositions of the cave like stalagmites. The analysis of the δ13C and δ18O isotopes in carbonate sediments provided information about the conditions at the time of precipitation of the carbonate material inside the cave. Similar analyses took place on samples near the archaeological findings and the results were correlated with archaeological data both in view of time and space. A general reconstruction of the period of human occupation in the Katarraktes cave system was established, on the basis of a combination of archaeological and geochemical data.

  12. The fungal colonisation of rock-art caves: experimental evidence.

    PubMed

    Jurado, Valme; Fernandez-Cortes, Angel; Cuezva, Soledad; Laiz, Leonila; Cañaveras, Juan Carlos; Sanchez-Moral, Sergio; Saiz-Jimenez, Cesareo

    2009-09-01

    The conservation of rock-art paintings in European caves is a matter of increasing interest. This derives from the bacterial colonisation of Altamira Cave, Spain and the recent fungal outbreak of Lascaux Cave, France-both included in the UNESCO World Heritage List. Here, we show direct evidence of a fungal colonisation of rock tablets in a testing system exposed in Altamira Cave. After 2 months, the tablets, previously sterilised, were heavily colonised by fungi and bacteria. Most fungi isolated were labelled as entomopathogens, while the bacteria were those regularly identified in the cave. Rock colonisation was probably promoted by the dissolved organic carbon supplied with the dripping and condensation waters and favoured by the displacement of aerosols towards the interior of the cave, which contributed to the dissemination of microorganisms. The role of arthropods in the dispersal of spores may also help in understanding fungal colonisation. This study evidences the fragility of rock-art caves and demonstrates that microorganisms can easily colonise bare rocks and materials introduced into the cavity. PMID:19484211

  13. The fungal colonisation of rock-art caves: experimental evidence

    NASA Astrophysics Data System (ADS)

    Jurado, Valme; Fernandez-Cortes, Angel; Cuezva, Soledad; Laiz, Leonila; Cañaveras, Juan Carlos; Sanchez-Moral, Sergio; Saiz-Jimenez, Cesareo

    2009-09-01

    The conservation of rock-art paintings in European caves is a matter of increasing interest. This derives from the bacterial colonisation of Altamira Cave, Spain and the recent fungal outbreak of Lascaux Cave, France—both included in the UNESCO World Heritage List. Here, we show direct evidence of a fungal colonisation of rock tablets in a testing system exposed in Altamira Cave. After 2 months, the tablets, previously sterilised, were heavily colonised by fungi and bacteria. Most fungi isolated were labelled as entomopathogens, while the bacteria were those regularly identified in the cave. Rock colonisation was probably promoted by the dissolved organic carbon supplied with the dripping and condensation waters and favoured by the displacement of aerosols towards the interior of the cave, which contributed to the dissemination of microorganisms. The role of arthropods in the dispersal of spores may also help in understanding fungal colonisation. This study evidences the fragility of rock-art caves and demonstrates that microorganisms can easily colonise bare rocks and materials introduced into the cavity.

  14. Lava-substrate heat transfer: Laboratory experiments and thermodynamic modeling

    NASA Astrophysics Data System (ADS)

    Rumpf, M.; Fagents, S. A.; Hamilton, C. W.; Wright, R.; Crawford, I.

    2012-12-01

    We have performed laboratory experiments and numerical modeling to investigate the heat transfer from a lava flow into various substrate materials, focusing on the effects of the differing thermophysical properties of substrate materials. Initial motivation for this project developed from the desire to understand the loss of solar wind volatiles embedded in lunar regolith deposits that were subsequently covered by a lava flow. The Moon lacks a significant atmosphere and magnetosphere, leaving the surface regolith exposed to bombardment by solar flare and solar wind particles, and by the cosmogenic products of galactic cosmic rays. Preservation of particle-rich regolith deposits may have occurred by the emplacement of an active lava flow on top of the regolith layer, provided the embedded particles survive heating by the lava. During future expeditions to the lunar surface, ancient regolith deposits could be sampled through surface drilling to extract the extra-lunar particles, revealing a history of the solar activity and galactic events not available on the Earth. This project also has important implications for terrestrial lava flows, particularly in the prediction of lava flow hazards. Lava erupted on Earth may be emplaced on various substrates, including solid lava rock, volcanic tephra, sands, soils, etc. The composition, grain size, consolidation, moisture content, etc. of these materials will vary greatly and have different effects on the cooling of the flow. Accounting for specific properties of the substrate could be an important improvement in lava flow models We have performed laboratory experiments in collaboration with the Department of Art and Art History at the University of Hawaii at Manoa in which ~5-6 kg of basalt, collected at Kilauea Volcano, Hawaii, is melted to ~1200 °C. The lava is poured into a device constructed of calcium silicate sheeting that has been filled with a solid or particulate substrate material and embedded with thermocouples

  15. The evolution of cave systems from the surface to subsurface

    SciTech Connect

    Loucks, R.G. ); Handford, C.R. )

    1996-01-01

    Many carbonate reservoirs are the result of cave-forming processes. The origin and recognition of fractures, breccias, and sediment fills associated with paleocaves were determined through the study of modern and paleocaves systems. Cave formation and destruction are the products of near-surface processes. Near-surface processes include solutional excavation, clastic and chemical sedimentation, and collapse of cave walls and ceilings. Cave sediment is derived from inside and/or outside the system. Depositional mechanisms include suspension, tractional, mass-flow and rock-fall. Collapse of ceilings and walls from chaotic breakdown breccias. These piles can be tens of meters thick and contain large voids and variable amounts of matrix. Cave-roof crackle breccia forms from stress-and tension-related fractures in cave-roof strata. As the cave-bearing strata subside into the subsurface, mechanical compaction increases and restructures the existing breccias and remaining cavities. Fracture porosity increases and breccia and vug porosity decreases. Large cavities collapse forming burial chaotic breakdown breccias. Differentially compacted strata over the collapsed chamber fracture and form burial cave-roof crackle breccias. Continued burial leads to more extensive mechanical compaction causing previously formed clasts to fracture and pack closer together. The resulting product is a rebrecciated chaotic breakdown breccia composed predominantly of small clasts. Rebrecciated blocks are often overprinted by crackling. Subsurface paleocave systems commonly have a complex history with several episodes of fracturing and brecciation. The resulting collapsed-paleocave reservoir targets are not single collapsed passages of tens of feet across, but are homogenized collapsed-cave systems hundreds to several thousand feet across.

  16. The evolution of cave systems from the surface to subsurface

    SciTech Connect

    Loucks, R.G.; Handford, C.R.

    1996-12-31

    Many carbonate reservoirs are the result of cave-forming processes. The origin and recognition of fractures, breccias, and sediment fills associated with paleocaves were determined through the study of modern and paleocaves systems. Cave formation and destruction are the products of near-surface processes. Near-surface processes include solutional excavation, clastic and chemical sedimentation, and collapse of cave walls and ceilings. Cave sediment is derived from inside and/or outside the system. Depositional mechanisms include suspension, tractional, mass-flow and rock-fall. Collapse of ceilings and walls from chaotic breakdown breccias. These piles can be tens of meters thick and contain large voids and variable amounts of matrix. Cave-roof crackle breccia forms from stress-and tension-related fractures in cave-roof strata. As the cave-bearing strata subside into the subsurface, mechanical compaction increases and restructures the existing breccias and remaining cavities. Fracture porosity increases and breccia and vug porosity decreases. Large cavities collapse forming burial chaotic breakdown breccias. Differentially compacted strata over the collapsed chamber fracture and form burial cave-roof crackle breccias. Continued burial leads to more extensive mechanical compaction causing previously formed clasts to fracture and pack closer together. The resulting product is a rebrecciated chaotic breakdown breccia composed predominantly of small clasts. Rebrecciated blocks are often overprinted by crackling. Subsurface paleocave systems commonly have a complex history with several episodes of fracturing and brecciation. The resulting collapsed-paleocave reservoir targets are not single collapsed passages of tens of feet across, but are homogenized collapsed-cave systems hundreds to several thousand feet across.

  17. IDENTIFICATION OF BAT ECTOPARASITE LEPTOCIMEX INORDINATUS FROM BAT-DWELLING CAVE, KANCHANABURI PROVINCE, THAILAND.

    PubMed

    Potiwat, Rutcharin; Sungvornyothin, Sungsit; Samung, Yudthana; Payakkapol, Anon; Apiwathnasorn, Chamnarn

    2016-01-01

    Bat bugs are blood-feeding insects of bats or warm blooded animals and humans. Since 2011, Leptocimex spp (Heteroptera: Cimicidae) has been reported in Thailand. However, microscopic examination of Leptocimex spp is complicated, especially when the entire body of the specimen is not available. To confirm the phenotypic identification of L. inordinatus from a limestone bat cave in Thailand, partial fragments of mitochondrial cytochrome c oxidase subunit 1 (COI) gene and 16S mitochondrial ribosomal DNA were PCR amplified and sequenced, which revealed 97% sequence identity with Cimicidae family members, being most similar to Cacodminae gen. sp. and C. vicinus, both bat bugs. Phylogenetic tree construction showed that L. inordinatus has a separate genetic lineage from that of with human bed bugs (Cimex hemipterus or C. lectularius), swallow bugs and other tick species. The presence of L. inordinatus in a bat-dwelling cave frequented by humans presents a potential public health problem requiring attention in particular regarding the possibility of zoonotic transmission of pathogens. PMID:27086421

  18. Monitoring of Bunker Cave (NW Germany): Assessing the complexity of cave environmental parameters

    NASA Astrophysics Data System (ADS)

    Riechelmann, Dana Fc; Schröder-Ritzrau, Andrea; Scholz, Denis; Spötl, Christoph; Richter, Detlev K.; Mangini, Augusto

    2010-05-01

    Bunker Cave (N 51° 22'03', E 7° 39'53') is located in the Rhenish Slate Mountains in the western part of Germany and is part of a giant cave system in the area of Iserlohn (Hammerschmidt et al., 1995).As part of the DAPHNE (Dated Speleothems - archives of the paleoenvironment) project Bunker Cave is being monitored since the end of 2006. The ongoing monitoring program is performed on a monthly base. Surface climate parameters are measured and samples of rain water, cave air, drip water at eight different drip sites and modern calcite precipitates from watch glasses placed beneath drip sites are collected. Data sets include temperature, precipitation, calculated infiltration, drip rates, electric conductivity, pH, alkalinity, cations, anions and stable isotopes. Bunker Cave shows a constant temperature throughout the year. Active calcite precipitation is higher in winter than in summer, which is due to lower cave pCO2 in winter. The generally low pCO2 values, however, support almost continuous calcite precipitation throughout the whole year. Drip water δ18O values reflect the mean annual isotopic composition of the rainfall in this area with no or less contribution of the summer rain. The slope of the MWL for local precipitation is close to the slope of both the global MWL and the local MWL at the nearby station Bad Salzuflen. The karst aquifer is well mixed as shown by the uniform drip water δ18O values. Hence, the site is well suited to detect multi-annual climate trends using stalagmite stable isotope records. In order to test the potential influence of kinetic isotope fractionation on the stable isotope signals at Bunker Cave, stable isotope data of modern calcite precipitated on watch glasses were compared to predicted values. Comparison of the δ18O values of in situ modern calcite precipitates with the δ18O values expected from equilibrium isotope fractionation suggests a small kinetic influence, which is probably related to the variability in drip rate

  19. Do cave features affect underground habitat exploitation by non-troglobite species?

    NASA Astrophysics Data System (ADS)

    Lunghi, Enrico; Manenti, Raoul; Ficetola, Gentile Francesco

    2014-02-01

    Many biospeleological studies focus on organisms that are exclusive inhabitants of the subterranean realm, but organisms that are not obligate cave-dwellers are frequent in caves, and may account for a substantial portion of biomass. Moreover, several taxa that are usually epigeous are regularly found inside caves, but for most of them it is unknown whether they accidentally enter them, or whether they actively select caves for specific environmental features. In this study we analysed the community of non-strict cave-dwelling organisms (amphibians, gastropods, spiders and orthopterans) in 33 caves from Central Italy, to assess how environmental factors determine community structure. Cave features strongly affected the distribution of the taxa considered. The combined effect of cave morphology and microclimate explained nearly 50% of the variation of community structure. Most of community variation occurred along a gradient from deep, dark and humid caves, to dry caves with wider entrances and extended photic areas. Most of species were associated with humid, deep and dark caves. Most of the non-troglobiont amphibians and invertebrates did not occur randomly in caves, but were associated to caves with specific environmental features. Analysing relationships between cave-dwelling species and environmental variables can allow a more ecological and objective classification of cave-dwelling organisms.

  20. A Gradual Compositional Change from Samoan Shield to Rejuvenated Lavas?

    NASA Astrophysics Data System (ADS)

    Konter, J. G.; Jackson, M. G.; Koppers, A. A.

    2013-12-01

    The geochemical evolution of intraplate volcanoes is often compared to the archetypal model derived from Hawaiian volcanoes that involves a mantle plume source with multiple components. In Samoa, a range in rock types, ages, and isotopic compositions have been obtained across a number of volcanic seamounts and islands. However, due to dense vegetation on the islands, stratigraphic relations are not well known, and therefore a sequence for the construction of Samoan volcanoes is not as well-defined as in Hawaii. On the three largest islands, a shield and a rejuvenated stage have been defined, whereas the existence of a post-shield stage has been suggested and questioned (Natland and Turner, 1985). Moreover, the existing shield isotopic compositions (particularly Sr) are distinct, spanning a larger range than in Hawaii. Tutuila only hosts a small amount of rejuvenated lavas, but they are similar to those of Upolu, and there is an isotopic and compositional overlap between Tutuila shield volcanics and the Upolu lavas. On the island of Upolu, roughly half the surface area is covered in rejuvenated lavas, while the other half consists of shield stage lavas. The shield lavas around Fagaloa Bay are compositionally similar to some of the Tutuila lavas. On the island of Savaii, rejuvenated volcanism covers nearly the entire island, showing similar compositions to Upolu rejuvenated volcanism. We here present new data for samples from a deep canyon in the interior of Savaii, which form the missing link in understanding the geochemical sequence of Samoan volcanic construction. In this canyon, an isotopically distinct composition is found that resembles the composition of Fagaloa lavas on Upolu, instead of the extremely radiogenic Sr isotope compositions dredged from the submarine base of Savaii that represent the early shield stage. In Fagaloa Bay, a slope break on the mountainside has been suggested to form the outline of a crater along which late-stage evolved lavas such as

  1. Calcite Farming at Hollow Ridge Cave: Calibrating Net Rainfall and Cave Microclimate to Dripwater and Calcite Chemical Variability

    NASA Astrophysics Data System (ADS)

    Tremaine, D. M.; Kilgore, B. P.; Froelich, P. N.

    2012-04-01

    Stable isotope (δ18O and δ13C) and trace element records in cave speleothems are often interpreted as climate changes in rainfall amount or source, cave air temperature, overlying vegetation and atmospheric pCO2. However, these records are difficult to verify without in situ calibration of changes in cave microclimate (e.g., net rainfall, interior ventilation changes) to contemporaneous variations in dripwater and speleothem chemistry. In this study at Hollow Ridge Cave (HRC) in Marianna, Florida (USA), cave dripwater, bedrock, and modern calcite (farmed in situ) were collected in conjunction with continuous cave air pCO2, temperature, barometric pressure, relative humidity, radon-222 activity, airflow velocity and direction, rainfall amount, and drip rate data [1]. We analyzed rain and dripwater δD and δ18O, dripwater Ca2+, pH, δ13C and TCO2, cave air pCO2 and δ13C, and farmed calcite δ18O and δ13C to examine the relationships among rainwater isotopic composition, cave air ventilation, cave air temperature, calcite growth rate and seasonal timing, and calcite isotopic composition. Farmed calcite δ13C decreases linearly with distance from the front entrance to the interior of the cave during all seasons, with a maximum entrance-to-interior gradient of Δδ13C = -7‰ . A whole-cave "Hendy test" at distributed contemporaneous farming sites reveals that ventilation induces a +1.9 ± 0.96‰ δ13C offset between calcite precipitated in a ventilation flow path and out of flow paths. Farmed calcite δ18O exhibits a +0.82 ± 0.24‰ offset from values predicted by both theoretical calcite-water calculations and by laboratory-grown calcite [2]. Unlike calcite δ13C, oxygen isotopes show no ventilation effects and are a function only of temperature. Combining our data with other speleothem studies, we find a new empirical relationship for cave-specific water-calcite oxygen isotope fractionation across a range of temperatures and cave environments: 1000 ln α = 16

  2. Spatial organization and connectivity of caves

    NASA Astrophysics Data System (ADS)

    Jouves, Johan; Viseur, Sophie; Guglielmi, Yves; Camus, Hubert

    2015-04-01

    The main particularity of karst systems is their hierarchical organization as three-dimensional network of conduits behaving as drain. They are recognized as having a major influence on fluid flow at reservoir scale. However, a karstic network is generally hardly continuously observable and their great intrinsic heterogeneity makes their characterization very complex. This media can be only observed by speleological investigation, conditioned to human possibilities. As a result, only few parts can be observed and therefore it is required to model the non-observable parts for reservoir characterizations. To provide realistic 3D models, non-observable karstic features will be generated using parameters extracted from observed ones. Morphometric analysis of the three-dimensional karstic network provides quantitative measures that can (i) give information on speleogenesis processes, (ii) be used to compare different karst systems, (iii) be correlated with hydrogeological behavior and (iii) control the simulation of realistic karst networks. Recent work done on the subject characterize the karstic network as a whole, without genetic a-priori. However, most of observable caves appears to have a polygenic history due to modifications in boundary conditions and some different karst features can be observed in a same cavity. To study the geometrical organization of caves, we propose to analyze 3D speleological topographies for which speleogenetic context is known. This way, it is possible to characterize karst features according to speleogenetic processes. Several morphometric descriptors have been calculated on three-dimensional topographies provided by speleological works. Some parameters describe the existence of preferential direction of karstification and preferential flow paths, other parameters describe the complexity, geometry and connectivity of the three-dimensional karstic networks. Through the study of fifteen different caves, 150km of 3D data have been analyzed

  3. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  4. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  5. 7 CFR 2902.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Bedding, bed linens, and towels. 2902.15 Section 2902... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  6. 7 CFR 2902.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Bedding, bed linens, and towels. 2902.15 Section 2902... PROCUREMENT Designated Items § 2902.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  7. 7 CFR 3201.15 - Bedding, bed linens, and towels.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Bedding, bed linens, and towels. 3201.15 Section 3201... PROCUREMENT Designated Items § 3201.15 Bedding, bed linens, and towels. (a) Definition. (1) Bedding is that..., bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding....

  8. Comparison of 3D point clouds produced by LIDAR and UAV photoscan in the Rochefort cave (Belgium)

    NASA Astrophysics Data System (ADS)

    Watlet, Arnaud; Triantafyllou, Antoine; Kaufmann, Olivier; Le Mouelic, Stéphane

    2016-04-01

    Amongst today's techniques that are able to produce 3D point clouds, LIDAR and UAV (Unmanned Aerial Vehicle) photogrammetry are probably the most commonly used. Both methods have their own advantages and limitations. LIDAR scans create high resolution and high precision 3D point clouds, but such methods are generally costly, especially for sporadic surveys. Compared to LIDAR, UAV (e.g. drones) are cheap and flexible to use in different kind of environments. Moreover, the photogrammetric processing workflow of digital images taken with UAV becomes easier with the rise of many affordable software packages (e.g. Agisoft, PhotoModeler3D, VisualSFM). We present here a challenging study made at the Rochefort Cave Laboratory (South Belgium) comprising surface and underground surveys. The site is located in the Belgian Variscan fold-and-thrust belt, a region that shows many karstic networks within Devonian limestone units. A LIDAR scan has been acquired in the main chamber of the cave (~ 15000 m³) to spatialize 3D point cloud of its inner walls and infer geological beds and structures. Even if the use of LIDAR instrument was not really comfortable in such caving environment, the collected data showed a remarkable precision according to few control points geometry. We also decided to perform another challenging survey of the same cave chamber by modelling a 3D point cloud using photogrammetry of a set of DSLR camera pictures taken from the ground and UAV pictures. The aim was to compare both techniques in terms of (i) implementation of data acquisition and processing, (ii) quality of resulting 3D points clouds (points density, field vs cloud recovery and points precision), (iii) their application for geological purposes. Through Rochefort case study, main conclusions are that LIDAR technique provides higher density point clouds with slightly higher precision than photogrammetry method. However, 3D data modeled by photogrammetry provide visible light spectral information

  9. Lunar Lava Tubes - The Promise of New Orbital Data

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.

    2009-01-01

    The basaltic plains of the Moon contain lava channels on scales of tens of meters to hundreds of kilometers. Many of these channels are segmented, strongly suggesting that some portions include covered lava tubes. Lunar lava tubes are expected to provide unique environments below the harsh lunar surface, maintaining near-isothermal conditions and substantial shielding from solar and galactic radiation. A lava tube has often been suggested as natural shelter for a future human outpost. Previous searches for lunar lava tubes have been limited by a combination of image resolution and completeness of coverage. The five robotic Lunar Orbiter spacecraft combined to photograph essentially the entire lunar surface with a resolution of 60 m, and covered selected sites with resolutions as high as 2 m. The highest-resolution Apollo images, from the mapping and panoramic cameras, covered swaths totaling 16% of the lunar surface, at resolutions of approximately 5 m. The Lunar Reconnaissance Orbiter -- launched in June 2009 to a polar orbit -- carries a suite of instruments that will revolutionize lunar remote sensing, including the identification and characterization of lava tubes. The Lunar Reconnaissance Orbiter Camera (LROC) system includes a multi-spectral wide-angle camera with a resolution of 70 m, allowing a comprehensive survey of the entire lunar surface. The LROC narrow-angle camera is providing targeted images at resolutions of 0.5 - 2 m, including stereo coverage, which should allow detection of tube entrances and breakdown structures. The Lunar Orbiter Laser Altimeter is producing a global topographic map with a vertical resolution of 1 m and a horizontal resolution of 50 m. These data will be critical to understanding lava dynamics and tube emplacement.

  10. Rheology of lava flows on Mercury: An analog experimental study

    NASA Astrophysics Data System (ADS)

    Sehlke, A.; Whittington, A. G.

    2015-11-01

    We experimentally determined the rheological evolution of three basaltic analog compositions appropriate to Mercury's surface, during cooling, and crystallization. Investigated compositions are an enstatite basalt, and two magnesian basalts representing the compositional end-members of the northern volcanic plains with 0.19 wt % (NVP) and 6.26 wt % Na2O (NVP-Na). The viscosity-strain rate dependence of lava was quantified using concentric cylinder viscometry. We measured the viscosities of the crystal-free liquids from 1600°C down to the first detection of crystals. Liquidus temperatures of the three compositions studied are around 1360°C, and all three compositions are more viscous than Hawaiian basalt at the same temperature. The onset of pseudoplastic behavior was observed at crystal fractions ~0.05 to 0.10, which is consistent with previous studies on mafic lavas. We show that all lavas develop detectable yield strengths at crystal fractions around 0.20, beyond which the two-phase suspensions are better described as Herschel-Bulkley fluids. By analogy with the viscosity-strain rate conditions at which the pahoehoe to `a`a transition occurs in Kilauea basalt, this transition is predicted to occur at ~1260 ± 10°C for the enstatite basalt, at ~1285 ± 20°C for the NVP, and at ~1240 ± 40°C for the NVP-Na lavas. Our results indicate that Mercury lavas are broadly similar to terrestrial ones, which suggests that the extensive smooth lava plains of Mercury could be due to large effusion rates (flood basalts) and not to unusually fluid lavas.

  11. Fractal analysis: A new remote sensing tool for lava flows

    NASA Technical Reports Server (NTRS)

    Bruno, B. C.; Taylor, G. J.; Rowland, S. K.; Lucey, P. G.; Self, S.

    1992-01-01

    Many important quantitative parameters have been developed that relate to the rheology and eruption and emplacement mechanics of lavas. This research centers on developing additional, unique parameters, namely the fractal properties of lava flows, to add to this matrix of properties. There are several methods of calculating the fractal dimension of a lava flow margin. We use the 'structured walk' or 'divider' method. In this method, we measure the length of a given lava flow margin by walking rods of different lengths along the margin. Since smaller rod lengths transverse more smaller-scaled features in the flow margin, the apparent length of the flow outline will increase as the length of the measuring rod decreases. By plotting the apparent length of the flow outline as a function of the length of the measuring rod on a log-log plot, fractal behavior can be determined. A linear trend on a log-log plot indicates that the data are fractal. The fractal dimension can then be calculated from the slope of the linear least squares fit line to the data. We use this 'structured walk' method to calculate the fractal dimension of many lava flows using a wide range of rod lengths, from 1/8 to 16 meters, in field studies of the Hawaiian islands. We also use this method to calculate fractal dimensions from aerial photographs of lava flows, using lengths ranging from 20 meters to over 2 kilometers. Finally, we applied this method to orbital images of extraterrestrial lava flows on Venus, Mars, and the Moon, using rod lengths up to 60 kilometers.

  12. The origin and evolution of lavas from Haleakala Crater, Hawaii

    SciTech Connect

    West, H.B.

    1988-01-01

    Sr, Nd, and Pb isotope systematics of lavas from the Maui Volcanic Complex (MVC) are consistent with a three-component petrogenetic mixing model. MVC shield-building (SB) lavas define linear trends on isotope-isotope plots, consistent with two-component mixing between primitive (PM) and enriched (EM) mantle components. The two-component (PM-EM) Hawaiian plume source is variable in composition during production of tholeiite magmas even within a single shield. Sr and Pb isotopic ratios of Haleakala post shield-building (PSB) lavas define a strong positively correlated array that deviates from the SB array towards an unradiogenic end-member. The PSB array may therefore result from time- and volume-dependent binary mixing between Hawaiian plume melts and a depleted (DM) mantle (i.e. MORB source) component. Several trace element ratios in Haleakala PSB lavas are correlated with isotopic compositions but not with major and trace element contents, and therefore appear to reflect changes in source composition. Trace element mixing systematics for these lavas indicate that the DM component must be a melt. The inferred PM component has chondritic ratios for several trace elements, consistent with it representing primitive mantle. The EM component may represent apart of the Hawaiian plume source that was either metasomatized or metasomatically scavenged. Alkalic cap lavas exposed in the northwest wall of Haleakala Crater display systematic, upsection geochemical variations indicative of the repetitive intrusion of discrete magma batches. In contrast, lava compositions within magma batches vary upsection progressively, and geochemical variations are opposite to those observed for interbatch discontinuities.

  13. Hidden Outgassing Dynamics at Kilauea (Hawaii) Lava Lake

    NASA Astrophysics Data System (ADS)

    Del Bello, E.; Taddeucci, J.; Orr, T. R.; Houghton, B. F.; Scarlato, P.; Patrick, M. R.

    2014-12-01

    Lava lakes offer unique opportunities for understanding how magmatic volatiles physically escape from low-viscosity, vesicular magma in open-vent conditions, a process often referred to as magma outgassing. Large-scale lava convection movements and meter-scale bubble explosions, sometimes triggered by rock falls, are acknowledged outgassing processes but may not be the only ones. In 2013 we used high-frequency (50-500 Hz) thermal and visible imaging to investigate the short-timescale dynamics of the currently active Halema`uma`u lava lake. At that time, besides the dominant release of large bubbles, three types of peculiar outgassing features were observed on the lava lake surface. The first, diffusely observed throughout the observation experiment, consisted of prolonged (up to seconds) gas venting from 'spot vents'. These vents appeared to open and close without the ejection of material or bubble bursting, and were the site of hot gas emission. Spot vents were located both between and inside cooling plates, and followed the general circulation pattern together with the rest of the lava lake surface. The second feature, observed only once, consisted of the transient wobbling of the whole lava lake surface. This wobbling, with a wavelength of meters to tens of meters, was not related to any external trigger, and dampened soon without apparent consequences on the other lake dynamics. Finally, we observed large (meters) doming areas of the lake surface randomly fluctuating over seconds to minutes. These areas were either stationary or moved independently of the general lake surface circulation, and usually were not affected by other lake surface features (e.g., cooling plate boundaries). These three features, though trivial for the overall lake outgassing, testify that the lava lake has a complex shallow subsurface architecture, in which permeable channels and gas pockets act independently of the more common bubble bursts.

  14. ComputerApplications and Virtual Environments (CAVE)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Virtual Reality (VR) can provide cost effective methods to design and evaluate components and systems for maintenance and refurbishment operations. The Marshall Space Flight Centerr (MSFC) in Huntsville, Alabama began to utilize VR for design analysis in the X-34 experimental reusable space vehicle. Analysts at MSFC's Computer Applications and Virtual Environments (CAVE) used Head Mounted Displays (HMD) (pictured), spatial trackers and gesture inputs as a means to animate or inhabit a properly sized virtual human model. These models were used in a VR scenario as a way to determine functionality of space and maintenance requirements for the virtual X-34. The primary functions of the virtual X-34 mockup was to support operations development and design analysis for engine removal, the engine compartment and the aft fuselage. This capability provided general visualization support to engineers and designers at MSFC and to the System Design Freeze Review at Orbital Sciences Corporation (OSC). The X-34 program was cancelled in 2001.

  15. ComputerApplications and Virtual Environments (CAVE)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Virtual Reality (VR) can provide cost effective methods to design and evaluate components and systems for maintenance and refurbishment operations. The Marshall Space Flight Center (MSFC) in Huntsville, Alabama began to utilize VR for design analysis in the X-34 experimental reusable space vehicle. Analysts at MSFC's Computer Applications and Virtual Environments (CAVE) used Head Mounted Displays (HMD) (pictured), spatial trackers and gesture inputs as a means to animate or inhabit a properly sized virtual human model. These models were used in a VR scenario as a way to determine functionality of space and maintenance requirements for the virtual X-34. The primary functions of the virtual X-34 mockup was to support operations development and design analysis for engine removal, the engine compartment and the aft fuselage. This capability providedgeneral visualization support to engineers and designers at MSFC and to the System Design Freeze Review at Orbital Sciences Corporation (OSC). The X-34 program was cancelled in 2001.

  16. Computer Applications and Virtual Environments (CAVE)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Virtual Reality (VR) can provide cost effective methods to design and evaluate components and systems for maintenance and refurbishment operations. Marshall SPace Flight Center (MSFC) is begirning to utilize VR for design analysis in the X-34 experimental reusable space vehicle. Analysts at MSFC's Computer Applications and Virtual Environments (CAVE) used Head Mounted Displays (HMD) (pictured), spatial trackers and gesture inputs as a means to animate or inhabit a properly sized virtual human model. These models are used in a VR scenario as a way to determine functionality of space and maintenance requirements for the virtual X-34. The primary functions of the virtual X-34 mockup is to support operations development and design analysis for engine removal, the engine compartment and the aft fuselage. This capability provides general visualization support to engineers and designers at MSFC and to the System Design Freeze Review at Orbital Sciences Corporation (OSC).

  17. Contemporary flowstone development links early hominin bearing cave deposits in South Africa

    NASA Astrophysics Data System (ADS)

    Pickering, Robyn; Kramers, Jan D.; Hancox, Philip John; de Ruiter, Darryl J.; Woodhead, Jon D.

    2011-06-01

    The Cradle of Humankind cave sites in South Africa preserve fossil evidence of four early hominin taxa: Australopithecus africanus, Australopithecus sediba, Paranthropus robustus and early Homo. In order to integrate this record into a pan-African scenario of human evolutionary history it is critical to have reliable dates and temporal ranges for the southern African hominins. In the past a lack of precise and accurate chronological data has prevented the evaluation of the temporal relationships between the various sites. Here we report new uranium-lead (U-Pb) radiometric ages obtained from sheets of calcium carbonate flowstone inter-bedded between clastic cave sediments at the site of Swartkrans, providing bracketing ages for the fossiliferous deposits. The fossil bearing units of Swartkrans, specifically the Hanging Remnant and Lower Bank of Member 1, are underlain by flowstone layers dated to 2.25 ± 0.05 Ma and 2.25 ± 0.08 Ma and capped by layers of 1.8 ± 0.01 Ma and 1.7 ± 0.07 Ma. The age bracket of the Member 1 deposits is therefore between 2.31 and 1.64 Ma. However, by combining the U-Pb with biostratigraphic data we suggest that this can be narrowed down to between 1.9 and 1.8 Ma. These data can be compared with other recently dated sites and a radiometrically dated U-Pb age sequence formed: Sterkfontein Member 4, Swartkrans Member 1, Malapa, and Cooper's D. From this new U-Pb dataset, a pattern of contemporary flowstone development emerges, with different caves recording the same flowstone-forming event. Specifically overlapping flowstone formation takes place at Swartkrans and Sterkfontein at ~ 2.29 Ma and ~ 1.77 Ma, and at Sterkfontein and Malapa at ˜ 2.02 Ma. This suggests a regional control over the nature and timing of speleothem development in cave deposits and these flowstone layers could assist in future correlation, both internal to specific deposits and regionally between sites.

  18. Bedrock Channel and Cave Evolution Models Based on Computational Fluid Dynamics

    NASA Astrophysics Data System (ADS)

    Perne, M.; Covington, M. D.; Cooper, M.

    2014-12-01

    Models of bedrock channel cross-section evolution typically rely on simple approximations of boundary shear stress to calculate erosion rates across the channel. While such models provide a useful tool for gaining general insight into channel dynamics, they also exhibit a narrower range of behaviors than seen in nature and scale experiments. Recent computational advances enable use of computational fluid dynamics (CFD) to relax many of the assumptions used in these simple models by simulating the full 3D flow field and resulting erosion. We have developed a model of bedrock channel evolution at the reach scale, using CFD, that alternates flow simulation steps with channel evolution steps and evolves the channel in time according to shear stresses calculated from the CFD runs. Caves provide an ideal field setting for studying bedrock channel dynamics, because long records of incision are often preserved in the form of channel widths, meander patterns, and sculpted forms, such as scallops, that indicate flow velocity and direction. However, most existing numerical models of cave formation investigate processes on larger scales, treat conduits as simple shapes, such as cylinders, and deal with the early stages of speleogenesis when sediment transport and erosion mechanisms other than dissolution do not have to be taken into account. Therefore, initial applications of the CFD model focus on the dynamics of cave channels, and particularly on the controls of channel width. While discharge, base level, sediment supply, and the ratio of dissolution to mechanical erosion, are likely to play important roles in determining channel width, we lack a quantitative understanding for the importance of these various factors. Notches in passage walls are thought to result from lateral erosion during periods of increased sediment load when the bed is armored. Modeling is used to check the plausibility of this explanation, and examine whether other mechanisms may also produce notches

  19. Hybrid fluidized bed combuster

    DOEpatents

    Kantesaria, Prabhudas P.; Matthews, Francis T.

    1982-01-01

    A first atmospheric bubbling fluidized bed furnace is combined with a second turbulent, circulating fluidized bed furnace to produce heat efficiently from crushed solid fuel. The bed of the second furnace receives the smaller sizes of crushed solid fuel, unreacted limestone from the first bed, and elutriated solids extracted from the flu gases of the first bed. The two-stage combustion of crushed solid fuel provides a system with an efficiency greater than available with use of a single furnace of a fluidized bed.

  20. Clumped isotope thermometry of cryogenic cave carbonates

    NASA Astrophysics Data System (ADS)

    Kluge, Tobias; Affek, Hagit P.; Zhang, Yi Ge; Dublyansky, Yuri; Spötl, Christoph; Immenhauser, Adrian; Richter, Detlev K.

    2014-02-01

    Freezing of cave pool water that is increasingly oversaturated with dissolved carbonate leads to precipitation of a very specific type of speleothems known as cryogenic cave carbonates (CCC). At present, two different environments for their formation have been proposed, based on their characteristic carbon and oxygen isotope ratios. Rapidly freezing thin water films result in the fast precipitation of fine-grained carbonate powder (CCCfine). This leads to rapid physicochemical changes including CO2 degassing and CaCO3 precipitation, resulting in significantly 13C-enriched carbonates. Alternatively, slow carbonate precipitation in ice-covered cave pools results in coarse crystalline CCC (CCCcoarse) yielding strongly 18O-depleted carbonate. This is due to the formation of relatively 18O-enriched ice causing the gradual depletion of 18O in the water from which the CCC precipitates. Cryogenic carbonates from Central European caves were found to have been formed primarily during the last glacial period, specifically during times of permafrost thawing, based on the oxygen isotope ratios and U-Th dating. Information about the precise conditions of CCCcoarse formation, i.e. whether these crystals formed under equilibrium or disequilibrium conditions with the parent fluid, however, is lacking. An improved understanding of CCCcoarse formation will increase the predictive value of this paleo-permafrost archive. Here we apply clumped isotopes to investigate the formation conditions of cryogenic carbonates using well-studied CCCcoarse from five different cave systems in western Germany. Carbonate clumped isotope measurements yielded apparent temperatures between 3 and 18 °C and thus exhibit clear evidence of isotopic disequilibrium. Although the very negative carbonate δ18O values can only be explained by gradual freezing of pool water accompanied by preferential incorporation of 18O into the ice, clumped isotope-derived temperatures significantly above expected freezing

  1. Dated rock engravings from Wonderwerk Cave, South Africa

    SciTech Connect

    Thackeray, A.I.; Thackeray, J.F.; Beaumont, P.B.; Vogel, J.C.

    1981-10-02

    Radiocarbon dates associated with engraved stones from sealed archeological deposits at Wonderwerk Cave in the northern Cape Province indicate that rock engraving in South Africa is at least 10,000 years old.

  2. Further constraints on the Chauvet cave artwork elaboration.

    PubMed

    Sadier, Benjamin; Delannoy, Jean-Jacques; Benedetti, Lucilla; Bourlès, Didier L; Jaillet, Stéphane; Geneste, Jean-Michel; Lebatard, Anne-Elisabeth; Arnold, Maurice

    2012-05-22

    Since its discovery, the Chauvet cave elaborate artwork called into question our understanding of Palaeolithic art evolution and challenged traditional chronological benchmarks [Valladas H et al. (2001) Nature 413:419-479]. Chronological approaches revealing human presences in the cavity during the Aurignacian and the Gravettian are indeed still debated on the basis of stylistic criteria [Pettitt P (2008) J Hum Evol 55:908-917]. The presented (36)Cl Cosmic Ray Exposure ages demonstrate that the cliff overhanging the Chauvet cave has collapsed several times since 29 ka until the sealing of the cavity entrance prohibited access to the cave at least 21 ka ago. Remarkably agreeing with the radiocarbon dates of the human and animal occupancy, this study confirms that the Chauvet cave paintings are the oldest and the most elaborate ever discovered, challenging our current knowledge of human cognitive evolution. PMID:22566649

  3. Ancient photosynthetic eukaryote biofilms in an Atacama Desert coastal cave

    USGS Publications Warehouse

    Azua-Bustos, A.; Gonzalez-Silva, C.; Mancilla, R.A.; Salas, L.; Palma, R.E.; Wynne, J.J.; McKay, C.P.; Vicuna, R.

    2009-01-01

    Caves offer a stable and protected environment from harsh and changing outside prevailing conditions. Hence, they represent an interesting habitat for studying life in extreme environments. Here, we report the presence of a member of the ancient eukaryote red algae Cyanidium group in a coastal cave of the hyperarid Atacama Desert. This microorganism was found to form a seemingly monospecific biofilm growing under extremely low photon flux levels. Our work suggests that this species, Cyanidium sp. Atacama, is a new member of a recently proposed novel monophyletic lineage of mesophilic "cave" Cyanidium sp., distinct from the remaining three other lineages which are all thermo-acidophilic. The cave described in this work may represent an evolutionary island for life in the midst of the Atacama Desert. ?? Springer Science + Business Media, LLC 2009.

  4. 5. Photographic copy of historic photograph (from Wind Cave National ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. Photographic copy of historic photograph (from Wind Cave National Park), photographer unknown, date unknown. Route 87, Beaver Creek Bridge, elevation. - Beaver Creek Bridge, Hot Springs, Fall River County, SD

  5. Further constraints on the Chauvet cave artwork elaboration

    PubMed Central

    Sadier, Benjamin; Delannoy, Jean-Jacques; Benedetti, Lucilla; Bourlès, Didier L.; Jaillet, Stéphane; Geneste, Jean-Michel; Lebatard, Anne-Elisabeth; Arnold, Maurice

    2012-01-01

    Since its discovery, the Chauvet cave elaborate artwork called into question our understanding of Palaeolithic art evolution and challenged traditional chronological benchmarks [Valladas H et al. (2001) Nature 413:419–479]. Chronological approaches revealing human presences in the cavity during the Aurignacian and the Gravettian are indeed still debated on the basis of stylistic criteria [Pettitt P (2008) J Hum Evol 55:908–917]. The presented 36Cl Cosmic Ray Exposure ages demonstrate that the cliff overhanging the Chauvet cave has collapsed several times since 29 ka until the sealing of the cavity entrance prohibited access to the cave at least 21 ka ago. Remarkably agreeing with the radiocarbon dates of the human and animal occupancy, this study confirms that the Chauvet cave paintings are the oldest and the most elaborate ever discovered, challenging our current knowledge of human cognitive evolution. PMID:22566649

  6. 75 FR 21039 - Notice of Temporary Road Closure of Coal Pit Spring-Cave Gulch Road (6287-0-B0), Within the Cave...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-22

    ... Bureau of Land Management Notice of Temporary Road Closure of Coal Pit Spring--Cave Gulch Road (6287-0-B0), Within the Cave Gulch Area, Oregon AGENCY: Bureau of Land Management, Interior. ACTION: Notice of... (BLM), in the Cave Gulch area, approximately 11 miles northwest of Burns, in Harney County,...

  7. Radon Dose Determination for Cave Guides in Czech Republic

    NASA Astrophysics Data System (ADS)

    Thinova, Lenka; Rovenska, Katerina

    2008-08-01

    According to recommended approach there are six (from total of twelve) open-to-public caves in Czech Republic, reaching near to an effective lung-dose of 6mSv/year. A conservative approach for estimating the potential effective lung-dose in caves (or underground) is based on two season's measurements, using solid state alpha track detector (Kodak in plastic diffusion chamber). The obtained dataset is converted into an annual effective dose, in agreement with the ICRP65 recommendation, using the "cave factor" 1.5. The value of "cave factor" which depends on the spectrum of aerosol particles, or on the proportional representation of the unattached/attached ratio (6.5 : 93.5 for residential places, 13.6 : 86.4 for caves due to lower concentration of free aerosols) and on the equilibrium factor. Thus conversion factor is 1.5 times higher in comparison with ICRP 65. Is this correct? Because a more precisely determined dose value would have a significant impact on radon remedies, or on restricting the time workers stay underground, a series of measurement was initiated in 2003 with the aim to specify input data, computation and errors in effective dose assessment in each one of the evaluated caves separately. The enhancement of personal dosimetry for underground work places includes a study of the given questions, from the following points of view in each cave: continual radon measurement; regular measurements of radon and its daughters to estimate the equilibrium factor and the presence of free 218Po; regular indoor air flow measurements to study the location of the radon supply and its transfer among individual areas of the cave; natural radioactive element content evaluation in subsoil and in water inside/outside, a study of the radon sources in the cave; determination of the free fraction from continual unattached and attached fraction measurement (grid and filter); thoron measurement. Air flow measurements provide very interesting information about the origin of

  8. Radon Dose Determination for Cave Guides in Czech Republic

    SciTech Connect

    Thinova, Lenka; Rovenska, Katerina

    2008-08-07

    According to recommended approach there are six (from total of twelve) open-to-public caves in Czech Republic, reaching near to an effective lung-dose of 6mSv/year. A conservative approach for estimating the potential effective lung-dose in caves (or underground) is based on two season's measurements, using solid state alpha track detector (Kodak in plastic diffusion chamber). The obtained dataset is converted into an annual effective dose, in agreement with the ICRP65 recommendation, using the 'cave factor' 1.5. The value of 'cave factor' which depends on the spectrum of aerosol particles, or on the proportional representation of the unattached/attached ratio (6.5 : 93.5 for residential places, 13.6 : 86.4 for caves due to lower concentration of free aerosols) and on the equilibrium factor. Thus conversion factor is 1.5 times higher in comparison with ICRP 65. Is this correct? Because a more precisely determined dose value would have a significant impact on radon remedies, or on restricting the time workers stay underground, a series of measurement was initiated in 2003 with the aim to specify input data, computation and errors in effective dose assessment in each one of the evaluated caves separately. The enhancement of personal dosimetry for underground work places includes a study of the given questions, from the following points of view in each cave: continual radon measurement; regular measurements of radon and its daughters to estimate the equilibrium factor and the presence of free {sup 218}Po; regular indoor air flow measurements to study the location of the radon supply and its transfer among individual areas of the cave; natural radioactive element content evaluation in subsoil and in water inside/outside, a study of the radon sources in the cave; determination of the free fraction from continual unattached and attached fraction measurement (grid and filter); thoron measurement. Air flow measurements provide very interesting information about the origin

  9. Late Holocene lava flow morphotypes of the northern Harrat Rahat, Kingdom of Saudi Arabia: implications for the description of continental lava fields

    NASA Astrophysics Data System (ADS)

    Murcia, H. F.; Nemeth, K.; Moufti, R.; Lindsay, J. M.; El-Masry, N.; Cronin, S. J.; Qaddah, A.; Smith, I. E.

    2013-12-01

    Lava morphotype refers to the surface morphology of a lava flow after solidification. In Saudi Arabia, young and well-preserved mafic lava fields (Harrats) display a wide range of these morphotypes. This study examines those exhibited by four of the post-4500 yrs. BP lava fields in the northern Harrat Rahat (<10 Ma) and describes these lava fields from general characteristics to detailed lava structures. This study also discusses the relationship between rheology and morphotypes, and proposes a preliminary correlation with whole-rock chemical composition. The Harrat Rahat lava fields include one or more lobes that may extend over 20 km from the source, with thicknesses varying between 1-2 m up to 12 m. Each lava flow episode covered areas between ~32 and ~61 km2, with individual volumes estimated between ~0.085 and ~0.29 km3. The whole-rock chemical compositions of these lavas lie between 44.3 to 48.4% SiO2, 9.01-4.28% MgO and 3.13-6.19% NaO+K2O. Seven different morphotypes with several lava structures are documented: Shelly, Slabby, Rubbly-pahoehoe, Platy, Cauliflower, Rubbly-a'a, and Blocky. These may be related to the shear strain and/or apparent viscosity of the lava flows formed from typical pahoehoe (pure or Hawaiian-pahoehoe, or sheet-pahoehoe). The well-preserved lava fields in Harrat Rahat allow the development of a more expanded classification scheme than has been traditionally applied. In addition to the whole-rock composition, these morphotypes may be indicators of other properties such as vesicularity, crystallization, effusion mechanism, as well as significant along-flow variations in topography and lava thickness and temperature that modify the rheology. The linearity of transitions between morphotypes observed in the lava fields suggest that real time forecasting of the evolution of lava flows might be possible.

  10. Analogue experiments as benchmarks for models of lava flow emplacement

    NASA Astrophysics Data System (ADS)

    Garel, F.; Kaminski, E. C.; Tait, S.; Limare, A.

    2013-12-01

    During an effusive volcanic eruption, the crisis management is mainly based on the prediction of lava flow advance and its velocity. The spreading of a lava flow, seen as a gravity current, depends on its "effective rheology" and on the effusion rate. Fast-computing models have arisen in the past decade in order to predict in near real time lava flow path and rate of advance. This type of model, crucial to mitigate volcanic hazards and organize potential evacuation, has been mainly compared a posteriori to real cases of emplaced lava flows. The input parameters of such simulations applied to natural eruptions, especially effusion rate and topography, are often not known precisely, and are difficult to evaluate after the eruption. It is therefore not straightforward to identify the causes of discrepancies between model outputs and observed lava emplacement, whereas the comparison of models with controlled laboratory experiments appears easier. The challenge for numerical simulations of lava flow emplacement is to model the simultaneous advance and thermal structure of viscous lava flows. To provide original constraints later to be used in benchmark numerical simulations, we have performed lab-scale experiments investigating the cooling of isoviscous gravity currents. The simplest experimental set-up is as follows: silicone oil, whose viscosity, around 5 Pa.s, varies less than a factor of 2 in the temperature range studied, is injected from a point source onto a horizontal plate and spreads axisymmetrically. The oil is injected hot, and progressively cools down to ambient temperature away from the source. Once the flow is developed, it presents a stationary radial thermal structure whose characteristics depend on the input flow rate. In addition to the experimental observations, we have developed in Garel et al., JGR, 2012 a theoretical model confirming the relationship between supply rate, flow advance and stationary surface thermal structure. We also provide

  11. Geologic history of the Black Hills caves, South Dakota

    USGS Publications Warehouse

    Palmer, Arthur N.; Palmer, Margaret; Paces, James B.

    2016-01-01

    The caves reveal four phases of calcite deposition: eogenetic ferroan calcite (Mississippian replacement of sulfates); white scalenohedra in paleovoids deposited during deep post-Mississippian burial; palisade crusts formed during blockage of springs by Oligocene–Miocene continental sediments; and laminated crusts from late Pleistocene water-table fluctuations. The caves reveal more than 300 m.y. of geologic history and a close relationship to regional geologic events.

  12. Some Caves in tunnels in Dinaric karst of Croatia

    NASA Astrophysics Data System (ADS)

    Garasic, Mladen; Garasic, Davor

    2016-04-01

    In the last 50 years during the construction of almost all the tunnels in the Croatian Dinaric Karst thousands of caves have been encountered that represented the major problems during the construction works. Geological features (fissures, folding, faults, etc.) are described in this contribution, together with the hydrogeological conditions (rapid changes in groundwater levels). Special engineering geological exploration and survey of each cave, together with the stabilization of the tunnel ceiling, and groundwater protection actions according to basic engineering geological parameters are also presented. In karst tunneling in Croatia over 150 caves longer than 500 m have been investigated. Several caves are over 300 m deep (St. Ilija tunnel in Biokovo Mt), and 10 are longer than 1000 m (St.Rok tunnel, HE Senj and HE Velebit tunnels in Velebit Mt, Ucka tunnel in Ucka Mt, Mala kapela tunnel in Kapela Mt, caverns in HE Plat tunnel etc). Different solutions were chosen to cross the caves depending on the size and purpose of the tunnels (road, rail, pedestrian tunnel, or hydrotechnical tunnels). This is presentations of interesting examples of ceiling stabilization in big cave chambers, construction of bridges inside tunnels, deviations of tunnels, filling caves, grouting, etc. A complex type of karstification has been found in the cavern at the contact between the Palaeozoic clastic impervious formations and the Mesozoic complex of dolomitic limestones in the Vrata Tunnel and at the contact with flysch in the Učka Tunnel. However, karstification advancing in all directions at a similar rate is quite rare. The need to have the roadway and/or tunnel above water from a spring is the biggest possible engineering-geological, hydrogeological and civil engineering challenge. Significant examples are those above the Jadro spring (Mravinci tunnel) in flysch materials or above the Zvir spring in Rijeka (Katarina tunnel), and in fractured Mesozoic carbonates. Today in Croatian

  13. Climate control of rock magnetic properties of cave sediments

    NASA Astrophysics Data System (ADS)

    Panaiotu, Cristian George; Roban, Relu

    2013-04-01

    Rock magnetic parameters of sediments reflect palaeoenvironmental and paleoclimatic conditions during deposition in the marine and in the continental realm. Cyclical changes in the magnetic mineral assemblages occurring at the orbital periodicities involved in the standard Milankovitch theory have been observed in numerous sedimentary records confirming the relationship between rock magnetism and past global change. In this respect cave sediments were longtime neglected, but in the last decade several studies about magnetic properties of cave sediments have been published. These studies have shown that the magnetic susceptibility data of cave sediments reflect both long- and short-term climatic oscillations. Magnetic susceptibility variations are attributed to changes in climate-controlled pedogenesis and the production of low coercivity magnetic mineral phases, magnetite and maghemite, outside the cave. The soils are then washed, blown or tracked into the cave where they accumulate, creating the changes observed in rock magnetic data. We present several studies of rockmagnetism in cave sediments from the Apuseni and South Carpathians Mountains (Romania). In each cave we used various rockmagnetic methods (variation of magnetic susceptibility with fields, frequency and temperature, anisotropy of magnetic susceptibility, hysteresis properties) and sedimentologic (granulometry, calcimetry, LOI, geochemistry) methods to characterized the studied deposits. In general the sections are relative short both in length (2 to 9 m) and time and the source area of sediments is highly variable, which make difficult the interpretation of magnetic signal in terms of climate. The best results can be obtained from fine sediments. When several magnetic parameters from several caves are plotted together a clear trend can be observed, which can be interpreted in terms of paleoclimate. Low magnetic susceptibility and low frequency dependence magnitudes indicate times of cooler

  14. On lava dome growth, with application to the 1979 lava extrusion of the soufrière of St. Vincent

    NASA Astrophysics Data System (ADS)

    Huppert, Herbert E.; Shepherd, John B.; Haraldur Sigurdsson, R.; Sparks, Stephen J.

    1982-12-01

    A theoretical analysis is presented for the spread of a viscous liquid flowing under its own hydrostatic pressure on a horizontal surface in order to model lava dome formation. Two situations are considered in detail: the spreading of a constant volume of liquid and the case where the amount of liquid is continually increased. Experiments with silicone liquids show close agreement with theory. The formation of a basaltic andesite lava extrusion in 1979 on the crater floor of the Soufrière of St. Vincent (West Indies) provided the motivation for and an application of the model. The extrusion reached a diameter of 868 m and a height of 133 m over a period of 150 days. Over the first 90 days the growth relationships were consistent with those predicted by theory. Application of the theory to the Soufrière dome suggests an effective viscosity of 2 X 10 12 poise for the basaltic andesite lava. The large effective viscosity calculated for the lava may be attributed to the dominant influence of a high-viscosity skin which forms at the margins of the flow as it cools. After 70 days, the rate of growth of the extrusion markedly decreased because a substantial collar of rubble accumulated at the flow front. Due to this collar the growth of the extrusion ceased after 150 days. From approximately two weeks after the initiation of the extrusion, the discharge rate of lava decreased approximately linearly with increasing dome height. This observation suggests that the lava ascended under a decreasing hydrostatic driving pressure and that extrusion ceased when the lava column reached hydrostatic equilibrium.

  15. The Influence of Slope Breaks on Lava Flow Surface Disruption

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Fagents, Sarah A.; Wright, Robert

    2014-01-01

    Changes in the underlying slope of a lava flow impart a significant fraction of rotational energy beyond the slope break. The eddies, circulation and vortices caused by this rotational energy can disrupt the flow surface, having a significant impact on heat loss and thus the distance the flow can travel. A basic mechanics model is used to compute the rotational energy caused by a slope change. The gain in rotational energy is deposited into an eddy of radius R whose energy is dissipated as it travels downstream. A model of eddy friction with the ambient lava is used to compute the time-rate of energy dissipation. The key parameter of the dissipation rate is shown to be rho R(sup 2/)mu, where ? is the lava density and mu is the viscosity, which can vary by orders of magnitude for different flows. The potential spatial disruption of the lava flow surface is investigated by introducing steady-state models for the main flow beyond the steepening slope break. One model applies to slow-moving flows with both gravity and pressure as the driving forces. The other model applies to fast-moving, low-viscosity, turbulent flows. These models provide the flow velocity that establishes the downstream transport distance of disrupting eddies before they dissipate. The potential influence of slope breaks is discussed in connection with field studies of lava flows from the 1801 Hualalai and 1823 Keaiwa Kilauea, Hawaii, and 2004 Etna eruptions.

  16. Bed material agglomeration during fluidized bed combustion

    SciTech Connect

    Brown, R.C.; Dawson, M.R.; Noble, S.

    1993-02-01

    The purpose of this project is to determine the physical and chemical reactions which led to the undesired agglomeration of bed material during fluidized bed combustion and to relate these reactions to specific causes. Survey of industrial-scale fluidized bed combustors is being conducted to determine the occurrence of bed agglomeration and the circumstances under which agglomeration took place. This task should be finished by the end of February. Samples of bed material, agglomerate material, and boiler deposits are being requested from boiler operators as part of the survey. Once received, these sample will be analyzed to determine chemical and mineralogic composition. The bulk chemical determination will be performed using x-ray fluorescence and inductively coupled plasma-optical emission (ICP). Mineralogy will be detected by x-ray diffraction (XRD). Chemical and mineral reactions will be determined by scanning electron microscopy, optical microscopy, and electron microprobe.

  17. Isotopic dating of Lava Creek B tephra in terrace deposits along the Wind River, Wyoming--Implications for post 0. 6 Ma uplift of the Yellowstone hotspot

    SciTech Connect

    Izett, G.A.; Pierce, K.L.; Naeser, N.D. ); Jaworowski, C. . Dept. of Geology and Geophysics)

    1992-01-01

    Along the Wind River near Kinnear (Pavillon quadrangle), a meter-thick tephra layer occurs near the middle of a main-stem gravel deposit about 100 m above the river. On Muddy Ridge 25 km east of Kinnear, a Lava Creek B tephra layer occurs at the base of a terrace deposit about 100 m above Muddy Creek. Another Lava Creek B tephra site 67 km northwest and upstream from Kinnear occurs within main-stem gravels of a terrace deposit 145 m above the river. This upstream increase of 45 m of the tephra horizon raises the concern that the two tephra layers might not be of the same age. All three tephras contain the same assemblage of phenocrysts as that in the Lava Creek Tuff, Member B in Yellowstone National Park and the Lava Creek B volcanic ash bed of the Western U.S., and therefore they are arguably correlatives. The authors confirmed this petrographic correlation by isotopic dating of sanidine crystals recovered from cm-size pumice lapilli in the Kinnear tephra and from coarse-grained tephra at the Muddy Creek site. Laser total-fusion Ar-40-Ar-39 ages of sanidine from the two sites are coeval, 0.66[plus minus]0.01 Ma and 0.67[plus minus]0.01 Ma at Muddy Creek. Conventional K-Ar dating of sanidine from the tephra at the Cl453 site resulted in an age of 0.60[plus minus]0.02 Ma. Glass-mantled zircon crystals from the Cl453 site yielded a fission-track age of 0.67[plus minus]0.16 Ma. These isotopic ages are compatible with conventional K-Ar, Ar-40-Ar-39, and fission-track ages of the Lava Creek Tuff, Member B in Yellowstone National Park and other occurrences of Lava Creek B ash beds. The authors suggest that the terrace deposit that contains the Lava Creek B tephra rises from the Kinnear site northwest up the Wind River as a result of Quaternary uplift in the area of the Yellowstone hotspot.

  18. Evaluating genetic viability of pronghorn in Wind Cave National Park

    USGS Publications Warehouse

    Jenks, Jonathan A.; Jacques, Christopher N.; Sievers, Jaret D.; Klaver, Robert W.; Bowyer, R. Terry; Roddy, Daniel E.

    2006-01-01

    The pronghorn (Antilocapra americana) was reintroduced into Wind Cave National Park, South Dakota, in 1914 and thus, has inhabited the Park for almost a century. A decline in the population has raised concern for the continued existence of pronghorn inside Wind Cave National Park. Historically, pronghorn numbers reached greater than 300 individuals in the 1960’s but declined to about 30 individuals by 2002. The primary objective of our study was to evaluate genetic characteristics of pronghorn to determine if reduced heterozygosity contributed to the decline of pronghorn in Wind Cave National Park. Microsatellite DNA was collected from 75 pronghorn inhabiting Wind Cave National Park in western South Dakota (n = 11), northwestern South Dakota (n = 33), and southwestern South Dakota (n = 31). Pronghorn in Wind Cave National Park had similar levels of observed heterozygosity (0.473 to 0.594) and low inbreeding coefficients (-0.168 to 0.037) when compared with other populations in western South Dakota. Furthermore, indices of population structure indicated no differentiation occurred among pronghorn populations. Results indicated that genetic variability was not a primary factor in the decline of pronghorn in Wind Cave National Park.

  19. Practice Hospital Bed Safety

    MedlinePlus

    ... Bed? Todd says that there is no standard definition for hospital beds, a fact that consumers shopping ... in retail stores that don’t meet the definition of medical devices under the law, but which ...

  20. Fluidized bed combustion

    SciTech Connect

    Sowards, N.K.; Murphy, M.L.

    1992-04-07

    This patent describes a method of incinerating a fuel containing difficult to remove tramp comprising wire. It comprises placing of a fluid bed within a downwardly and inwardly tapered centrally hollow air distributor disposed within a lower portion of a vessel; introducing fuel comprising combustible material and tramp comprising wire into the fluid bed; incinerating the combustible material in the fluid bed accommodating downward migration within the fluid bed of the wire without a central obstruction to such migration; in the course of performing the incinerating step, fluidizing the bed solely by introducing inwardly at several tiered locations directed air into the bed only around the tapered periphery along the lower portion of the vessel from a plurality of inwardly and downwardly parallel sites as causing the bed material and tramp to migrate downwardly and inwardly without central bed obstruction toward a discharge site.

  1. Enuresis (Bed-Wetting)

    MedlinePlus

    ... their development. Bed-wetting is more common among boys than girls. What causes bed-wetting? A number of things ... valves in boys or in the ureter in girls or boys Abnormalities in the spinal cord A small bladder ...

  2. Gigantic self-confined pahoehoe inflated lava flows in Argentina

    NASA Astrophysics Data System (ADS)

    Pasquare', G.; Bistacchi, A.

    2007-05-01

    The largest lava flows on Earth are pahoehoe basalts emplaced by inflation, a process which can change lava lobes initially a few decimetres thick into large lava sheets several metres thick. Inflation involves the initial formation of a thin, solidified, viscoelastic crust, under which liquid lava is continually added. This thermally efficient endogenous growth process explains the spread of huge volumes of lava over large, almost flat areas, as in the sheet flows which characterise the distal portions of Hawaiian volcanoes or some continental flood basalt provinces. Long, narrow, inflated pahoehoe flows have occasionally been described, either emplaced along pre-existing river channels or confined within topographic barriers. In this contribution we present previously unknown inflated pahoehoe lava flows following very long, narrow pathways over an almost flat surface, with no topographic confinement. Lava, which erupted in Late Quaternary times from the eastern tip of a 60 km long volcanic fissure in Argentina, formed several discrete flows extending as far as 180 km from the source. This fissure was characterized by a long-lasting and complex activity. Alkali-basaltic lava flows were emitted at the two extremities of the fissure system. In the intermediate section of the fissure, the Payun Matru, a great trachitic composite volcano, developed, giving rise to a large caldera which produced large pyroclastic flows. Alkali-basalts predate and postdate the trachitic activity, in fact at the end of the trachitic activity, new basaltic lava flows (mainly aa) were emitted from both ends of the fissure. We studied in details the youngest of the gigantic flows (Pampas Onduladas lava flow), which progressively develops through differing thermally-efficient flow mechanisms. The flow created a large shield volcanic structure at the eastern tip of the E-W fissure and spread to the E forming a very large and thick inflated pahoehoe sheet flow. Leaving the flanks of the

  3. Bubbled lava from the floor of the Sea of Okhotsk

    NASA Astrophysics Data System (ADS)

    Baturin, G. N.; Dubinchuk, V. T.; Rashidov, V. A.

    2014-05-01

    A sample of bubbled lava raised from a submarine volcano in the Sea of Okhotsk was analyzed by means of electron microscopy and the ICP-MS technique. The outside of the sample is flecked with rounded micro- and macrocavities, and the inner part is characterized by a liquation structure. Along with this, the unstructured mass of the rock contains globular particles of nearly the same diameters as the cavities. The lava is close to andesites and volcanic ashes of Kamchatka Peninsula in the macro- and microelemental composition but different in the somewhat increased content of barium, strontium, lithium, niobium, tungsten, uranium, and thorium. It is suggested that the cavities were formed during the eruption of the submarine volcano owing to contact of the boiling gas-saturated lava with seawater accompanied by the ejection of ash, which was spread by marine currents over long distances.

  4. Insights into the dynamics of the Nyiragongo lava lake level

    NASA Astrophysics Data System (ADS)

    Smets, Benoît; d'Oreye, Nicolas; Geirsson, Halldor; Kervyn, Matthieu; Kervyn, François

    2016-04-01

    Nyiragongo volcano, in North Kivu, Democratic Republic of Congo, is among the most active volcanoes in Africa and on Earth. Since the first European observations in the late 19th Century, its eruptive activity mostly concentrated into its main crater, with the presence of a persistent lava lake from at least 1928 to 1977 and since 2002. The size, shape and elevation of this lava lake have evolved through time, modifying the topography of the main crater. In January 1977 and 2002, the uppermost magmatic system of Nyiragongo, including the lava lake, was drained during flank eruptions. These flank events caused major disasters, mostly due to the exceptionally fast-moving lava flows and the presence of a dense population living at foot of this volcano. Despite a large scientific interest and societal concern, the study of the eruptive activity of Nyiragongo remains limited by climate and vegetation conditions that, most of the time, limit use of satellite remote sensing techniques, and recurrent armed conflicts in the Kivu region, which sometimes prevent field access to the main crater. Here we focus on the dynamics of the Nyiragongo lava lake level and its relationship with the volcanic plumbing system by describing the historical and recent lava lake activity and presenting new quantitative observations using close-range photogrammetry, a Stereographic Time-Lapse Camera (STLC) system and high-resolution satellite SAR and InSAR remote sensing. Results highlight that, contrary to the interpretation found in some recent publications, the lava lake drainages appear to be the consequence and not the cause of the 1977 and 2002 flank eruptions. Two types of short-term lava lake level variations are observed. The first one corresponds to cyclic metre-scale variations attributed to gas piston activity. The STLC data recorded in September 2011 show hour-scale gas piston cycles reaching up to 3.8 m, which are interpreted to be related to gas accumulation and release in the

  5. Mare ridges and lava lakes. [Apollo 17 investigation

    NASA Technical Reports Server (NTRS)

    Hodges, C. A.

    1973-01-01

    The autointrusive hypothesis of the origin of several vagaries of prominent mare ridges is explained. Data are based on a comparison between the structure of a Hawaiian lava lake and the mare ridges. Resulting data suggest that these ridges may have formed as squeeze-ups and autointrusives in tension fractures over buried topography in the crust of luna lava lakes. Data also suggest that mare ridges may result from: (1) pressure ridges in flows, (2) compressional features resulting from subsidence of mare lava, (3) volcanic ring structures and extrusives, or loccoliths fed by lunar grid controlled dikes, (4) draped topography and fissure eruptives, (5) drag folds or tension-gash dikes caused by wrench faulting at depth, and (6) postmare thrust faults.

  6. Chasing lava: a geologist's adventures at the Hawaiian Volcano Observatory

    USGS Publications Warehouse

    Duffield, Wendell A.

    2003-01-01

    A lively account of the three years (1969-1972) spent by geologist Wendell Duffield working at the Hawaiian Volcano Observatory at Kilauea, one of the world's more active volcanoes. Abundantly illustrated in b&w and color, with line drawings and maps, as well. Volcanologists and general readers alike will enjoy author Wendell Duffield's report from Kilauea--home of Pele, the goddess of fire and volcanoes. Duffield's narrative encompasses everything from the scientific (his discovery that the movements of cooled lava on a lava lake mimic the movements of the earth's crust, providing an accessible model for understanding plate tectonics) to the humorous (his dog's discovery of a snake on the supposedly snake-free island) to the life-threatening (a colleague's plunge into molten lava). This charming account of living and working at Kilauea, one of the world's most active volcanoes, is sure to be a delight.

  7. Time for Bed Game

    MedlinePlus

    ... a Friend Who Cuts? Babysitting: Time for Bed Game KidsHealth > For Teens > Babysitting: Time for Bed Game Print A A A Text Size What Kids ... kids to bed can be tough sometimes! This game introduces children to the concept of getting enough ...

  8. Making a Bed

    ERIC Educational Resources Information Center

    Wexler, Anthony; Stein, Sherman

    2005-01-01

    The origins of this paper lay in making beds by putting pieces of plywood on a frame: If beds need to be 4 feet 6 inches by 6 feet 3 inches, and plywood comes in 4-foot by 8-foot sheets, how should one cut the plywood to minimize waste (and have stable beds)? The problem is of course generalized.

  9. Fluidized bed quenching technology

    SciTech Connect

    Reynoldson, R.

    1996-12-31

    The use of fluidized beds for quenching ferrous materials is outlined and compared with the more traditional techniques commonly used in the heat treatment industry. The use of fluidized bed quenching to control distortion of metal parts is also discussed. A case study is provided to illustrate a practical application of fluidized bed quenching.

  10. Lava Flow Hazard Assessment for the Idaho National Laboratory: A Probabilistic Approach to Modeling Lava Flow Inundation with MOLASSES

    NASA Astrophysics Data System (ADS)

    Gallant, E.; Connor, C.; Richardson, J. A.; Wetmore, P. H.; Connor, L.

    2015-12-01

    We present the results of a lava flow hazard assessment for the Idaho National Laboratory (INL) using a new lava flow code, MOLASSES (MOdular LAva Simulation Software for Earth Science). INL is a nuclear research and development facility located on the eastern Snake River Plain with the potential for lava flow inundation from both monogenetic and polygenetic basaltic eruptions. Previously published inventories of observed surface vents and vents that are buried by younger lava flows and inferred from interpretation of borehole stratigraphy were used to created spatial density maps of vents within the INL region. Monte carlo simulations were run using the MOLASSES code to compare the difference between events initiated using only surface vents and events initiated using both the surface and the buried vents. We find that the inclusion of the buried vent locations drastically increases the number of site inundations and events initiating within INL boundaries. This highlights the need to seek out a more complete eruption record in an area of heavy prehistoric activity to better assess future hazard and associated risk.

  11. Birth of a lava lake: Nyamulagira volcano 2011-2015

    NASA Astrophysics Data System (ADS)

    Coppola, D.; Campion, R.; Laiolo, M.; Cuoco, E.; Balagizi, C.; Ripepe, M.; Cigolini, C.; Tedesco, D.

    2016-03-01

    Since 1938, Nyamulagira volcano (Democratic Republic of Congo) has operated as a classic pressurized basaltic closed system, characterized by frequent dike-fed flank eruptions. However, on June 24, 2014, an active lava lake was observed in its summit, after a period of 76 years. The small lava lake is now exposed at the bottom of a pit-crater and is rising and growing. Based on satellite-derived infrared (IR) data, SO2 fluxes and periodic field surveys, we provide evidence that the development of the lava lake was gradual and occurred more than 2 years before it was first observed in the field. Notably, this process followed the voluminous 2011-2012 distal flank eruption and was coeval with weakening of the central rock column below the summit. Hence, the opening and development of the pit-crater favoured the continuous rise of fresh magma through the central conduit and promoted the gradual "re-birth" of the Nyamulagira lava lake. Budgeted volumes of magma erupted, and magma degassed at depth indicate that the formation of the lava lake is due to the draining and refilling of a shallow plumbing system (1-2 km depth), probably in response to the rift-parallel 2011-2012 distal eruption. We thus suggest that the transition from lateral to central activity did not result from a substantial change in the magma supply rate but, more likely, from the perturbation of the plumbing system (and related stress field) associated with the distal eruption. The processes observed at Nyamulagira are not unique and suggest that rift-fissure eruptions, in addition to triggering caldera collapses or lava lake drainages, may also induce a progressive resumption of central vent activity. Current activity at Nyamulagira represents a tangible and major hazard for the population living at the base of its southern flank.

  12. Crystallization history of the 1984 Mauna Loa lava flow

    NASA Technical Reports Server (NTRS)

    Crisp, Joe; Cashman, Katharine V.; Bonini, Jennifer A.; Hougen, Sarah B.; Pieri, David C.

    1994-01-01

    During a 3-week eruption in 1984, Mauna Loa produced vent lavas that increased in crystallinity from less than 1 to 30%, and 27-km-long flows that increased in crystallinity as they moved downstream. We examined the crystallization history of these lavas using crystal size distribution (CSD) analysis to study the rates of crystallization, viscosity increase, and latent heating. Typical average growth and nucleation rates were 5 x 10(exp -9) cm/s and 5/cu cm/s for microphenocrysts (20- to 500-micron size crystals nucleated in the rift zone) and 5 x 10(exp -8) cm/s and 5 x 10(exp 4)/cu cm/s for microlites (1- to 20-micron size crystals nucleated in the channel). These crystallization rates are high compared with those found in other CSD studies of igneous rocks, probably due to highly nonequilibrium conditions brought on by rapid degassing in the rift zone and cooling in the lava channel. Growth and nucleation rates decreased with time at the vent and with distance downstream. The maximum downstream total crystallinity measured is 39% (25% microlites, 14% microphenocrysts) in a quenched sample 14 km from the vent. Growth and nucleation rates cannot be calculated for postemplacement samples, but they place upper limits of 53-58% on the amount of crystallization in the channel 9-20 km from the vent. Crystallization could have been mostly responsible for the 10(exp 5)-fold downstream increase in apparent viscosity, although degassing and increasing incorporation of solid lava fragments also contributed. Another effect of crystallization on the lava flow was the sizeable latent heating (0.01 J/g/s over the first half of the flow length, if the crystallinity of downstream quench samples is representative of the hot fluid core), which may have been counteracted by entrainment of cooler material. Measurements of crystallization are shown to be crucial in the study of lava flow emplacement dynamics.

  13. Study of radiocarbon dynamics of Baradla Cave, Hungary

    NASA Astrophysics Data System (ADS)

    Molnár, Mihály; Dezsö, Zoltán; Futo, Istvan; Siklósy, Zoltan; Jull, A. J. Timothy; Koltai, Gabriella

    2016-04-01

    Carbon isotope composition of speleothems and their parent drip water reflects the isotope composition of the atmospheric CO2, the soil and the host rock and can sometimes be influenced even by the cave atmosphere. Owing to the fact that 14C in the bedrock has long decayed, the bedrock derived carbon content of the seepage water can be considered as inactive or "dead carbon". The initial dead carbon proportion (dcp) of a stalagmite or tufa layer, caused by the incorporation of the inactive carbon, can be calculated with the help of the C-14 level differences between the contemporary atmosphere and the formed stone carbonate. The revolutionary technological advances of 14C (AMS) have brought the possibility of analysing 14C dynamics of karst systems due to the small amount of demanded material. The Baradla-Domica Cave is the largest cave of Gömör-Torna Karst, a karst area situated in the northeast of Hungary, and located on the Slovakian-Hungarian borderland. The approximately 26 km long cave is a typical example of multi-level speleogenesis. As a case study we have investigated several recent (age < 50 years) and older (age about 10-11 kyrs) stalagmites and recent drip water, some freshwater tufa samples and the recent cave air carbon-dioxide of the Baradla-cave to study the carbon dynamics and dead carbon level there. According four modern stalagmites (formed 1991-2004) the current dcp is very small in Baradla Cave (3-7%). Stalagmites deposited in Holocene (U/Th dated) were also characterized by very small dead carbon contents (1-11% dcp). Outside the cave a dpc about 20-25% was found in a freshwater tufa sample. This relatively low dead carbon content might be either explained by the thinness of the limestone bedrock above (56-80 m) or the relatively fast infiltration conditions, or their combined effect. Cave air is enriched in CO2 (2-5 times higher than in natural air, not homogenous) but the source of this surplus CO2 is not the limestone according its

  14. Can subterranean cave systems affect soil CO2 fluxes?

    NASA Astrophysics Data System (ADS)

    Krajnc, Bor; Ferlan, Mitja; Ogrinc, Nives

    2015-04-01

    Main factors affecting soil CO2 fluxes in most ecosystems are soil temperature and soil moisture. Nevertheless occasionally high soil CO2 fluxes were observed at carst areas, which could result from ventilation of subterranean cavities (Ferlan et al., 2011). The aim of this work was to determine the influence of cave ventilation to soil CO2 fluxes. Research was done in a dead-end passage of Postojna cave (Pisani rov) and on the surface area above the passage (Velika Jeršanova dolina) in south-western Slovenia. Inside the cave we measured CO2 concentrations, its carbon (13C) stable isotope composition, 222Rn activity concentrations, temperatures and air pressure. At the surface we had chosen two sampling plots; test plot above the cave and control. At both plots we measured soil CO2 fluxes with automatic chambers, CO2 concentrations, temperatures and carbon stable isotope composition of soil air at three different depths (0.2 m, 0.5 m and 0.8 m) and different meteorological parameters such as: air temperature, air pressure, wind speed an precipitation. To detect the cave influence, we compared two surface CO2 flux measurements with air temperatures and changes of CO2 concentrations in the cave atmosphere. Our results on CO2 concentrations in the gallery of the cave indicated that the ventilation of this particular gallery also depends on outside air temperatures. Outside temperature increased and corresponded to higher CO2 concentrations, whereas at lower temperatures (T < 9 oC) cave started to ventilate and exhaled CO2 reach air through unknown fissures and cracks. At the control plot the soil CO2 fluxes were in a good correlation with soil temperatures (r = 0.789, p =0.01), where greater soil temperatures correspond to greater soil CO2 fluxes. Soil CO2 fluxes at the plot above the cave did not show statistically significant correlations with soil temperatures or soil moisture indicating that other factors possibly cave ventilation could influence it. References

  15. Boron isotopic constraints on the source of Hawaiian shield lavas

    NASA Astrophysics Data System (ADS)

    Tanaka, Ryoji; Nakamura, Eizo

    2005-07-01

    Boron isotopic compositions of lavas from three representative Hawaiian shield volcanoes (Kilauea, Mauna Loa, and Koolau) were analyzed by thermal ionization mass spectrometry. The boron isotopic composition of each sample was analyzed twice, once with and once without acid leaching to evaluate the effect of posteruptive boron contamination. Our acid-leaching procedure dissolved glass, olivine, secondary zeolite, and adsorbed boron; this dissolved boron was completely removed from the residue, which was comprised of plagioclase, pyroxenes, and newly formed amorphous silica. We confirmed that an appropriate acid-leaching process can eliminate adsorbed and incorporated boron contamination from all submarine samples without modifying the original 11B/ 10B ratio. On the other hand, when the sample was weathered, i.e., the olivine had an iddingsite rim, 11B/ 10B of the acid-resistant minerals are also modified, thus it is impossible to get the preeruptive 11B/ 10B value from the weathered samples. Through this elimination and evaluation procedure of posteruptive contamination, preeruptive δ 11B values for the shield lavas are -4.5 to -5.4‰ for Koolau ( N = 8), -3.6 to -4.6‰ for Kilauea ( N = 11), and -3.0 to -3.8‰ for Mauna Loa ( N = 6). Historical Kilauea lavas show a systematic temporal trend for B content and Nb/B coupled with other radiogenic isotopic ratios and trace element ratios, at constant δ 11B, indicating little or no assimilation of crustal materials in these lavas. Uncorrelated B content and δ 11B in Koolau and Mauna Loa lavas may also indicate little or no effect of crustal assimilation in these lavas. The source of KEA-component (identical to the so-called Kea end member in Hawaiian lavas) of the Hawaiian source mantle, represented by Kilauea, should be derived from lower part of subducted oceanic crust or refractory peridotite in the recycled subducted slab. The systematic trend from Kilauea to Koolau—decreasing δ 11B coupled with decreasing

  16. Late-stage flood lavas in the Elysium region, Mars

    NASA Technical Reports Server (NTRS)

    Plescia, J. B.

    1987-01-01

    In the southeastern part of the Elysium region is a unit that exhibits little texture and a generally low albedo and that has a very low crater frequency. This unit has been mapped as smooth plains material and previously interpreted as an eolian deposit on the basis of Mariner 9 images. More recently, the unit was mapped as material deposited during a channeling episode. The author interprets the smooth plains unit as being a volcanic deposit composed of low viscosity lava flows: both flood lavas and individual flows. The reasons for these conclusions are given and briefly discussed.

  17. Conveying Lava Flow Hazards Through Interactive Computer Models

    NASA Astrophysics Data System (ADS)

    Thomas, D.; Edwards, H. K.; Harnish, E. P.

    2007-12-01

    As part of an Information Sciences senior class project, a software package of an interactive version of the FLOWGO model was developed for the Island of Hawaii. The software is intended for use in an ongoing public outreach and hazards awareness program that educates the public about lava flow hazards on the island. The design parameters for the model allow an unsophisticated user to initiate a lava flow anywhere on the island and allow it to flow down-slope to the shoreline while displaying a timer to show the rate of advance of the flow. The user is also able to modify a range of input parameters including eruption rate, the temperature of the lava at the vent, and crystal fraction present in the lava at the source. The flow trajectories are computed using a 30 m digital elevation model for the island and the rate of advance of the flow is estimated using the average slope angle and the computed viscosity of the lava as it cools in either a channel (high heat loss) or lava tube (low heat loss). Even though the FLOWGO model is not intended to, and cannot, accurately predict the rate of advance of a tube- fed or channel-fed flow, the relative rates of flow advance for steep or flat-lying terrain convey critically important hazard information to the public: communities located on the steeply sloping western flanks of Mauna Loa may have no more than a few hours to evacuate in the face of a threatened flow from Mauna Loa's southwest rift whereas communities on the more gently sloping eastern flanks of Mauna Loa and Kilauea may have weeks to months to prepare for evacuation. Further, the model also can show the effects of loss of critical infrastructure with consequent impacts on access into and out of communities, loss of electrical supply, and communications as a result of lava flow implacement. The interactive model has been well received in an outreach setting and typically generates greater involvement by the participants than has been the case with static maps

  18. Thermo-Rheological Feedbacks in Silicic Lavas and Ignimbrites

    NASA Astrophysics Data System (ADS)

    Whittington, A. G.; Robert, G.; Andrews, G. D.; Avard, G.; Romine, W. L.; Ye, J.

    2012-12-01

    The rheology of lava is highly dependent on temperature, both directly (via non-Arrhenian temperature dependence of melt viscosity) and indirectly (via increasing crystal content). Rheology feeds back to temperature, because rapidly sheared melts can undergo viscous heating (heat production = viscosity × [strain rate]2), and rapid disequilibrium crystallization can cause heating due to latent heat release (ΔHxt). The heat budget of partially crystalline lava balances these gains with conductive losses controlled by thermal diffusivity (D) and conductivity (k = DρCP, where ρ is density and CP is heat capacity). We measured the apparent viscosity of several crystalline dacitic lavas from Santiaguito, Guatemala and Bezymianny, Kamchatka. At conditions appropriate to lava flows (shear stress ~0.1 to 0.4 MPa, strain rate ~10-8 to 10-5s-1), apparent viscosity is best modeled as a power-law with no yield strength. Viscosity of the flow core, at ~850°C, is estimated ~5×1010 Pa.s. There is no evidence for significant crystallization during flow emplacement at Santiaguito, but viscous heating may be significant ongoing heat source within these flows (~100Wm-3 if most shearing is restricted to a ~1m wide zone), enabling highly viscous lava to travel long distances (~4 km in ~2 yrs for Santiaguito). Extremely high-grade, lava-like welded ignimbrites are deposited by many of the largest explosive eruptions in Earth history with volumes typically ranging between 10 to 1000 km3 and volcanic explosivity indices of 8 to 9. The lava-like and rheomorphic Grey's Landing ignimbrite, Idaho, provides abundant field evidence supporting the upward-migration of a transient, 1 - 2 m thick, sub-horizontal ductile shear zone at the interface between the pyroclastic density current and deposit, through which all of the deposit passed. We test the syn-depositional shear zone model through a combination of rheological experiments and thermo-mechanical modeling. Our results demonstrate that

  19. Determining lava rheology using video velocimetry and flow models (Invited)

    NASA Astrophysics Data System (ADS)

    Lev, E.; Spiegelman, M. W.; Wysocki, R.; Karson, J. A.

    2013-12-01

    Flowing lava is one of the most common surface expressions of magmatic and volcanic processes, and thus provides an opportunity for measuring the physical properties of magma. However, direct and accurate field measurements are difficult to carry out, and thus flow models rely on estimates based from measurements of velocity and temperature made at the flow's surface. We demonstrate here how lava rheology can be assessed remotely using video velocimetry. We apply our method on lava flows of both laboratory and natural scales. Our experimental setup, part of the Syracuse University Lava Project (http://lavaproject.syr.edu) includes a large furnace capable of melting up to 450 kg of basalt. The lava is poured onto tilted planes or channels made of sand or steel to produce meters-long flows. This experimental setup is probably the only facility that allows such large scale controlled lava flows made of natural basaltic material. We document the lava using a high-resolution video camera, a forward-looking infrared (FLIR) camera and thermocouples. We employ Differential Optical Flow to extract surface velocity fields from video recordings of the experimental and natural flows. This technique uses the time-variations of the spatial gradients of the image intensity to estimate velocity between consecutive frames. An important benefit for using optical flow, compared with other velocimetry methods, is that it outputs a spatially coherent flow field rather than point measurements. We demonstrate that the optical flow results agree with other measures of the flow velocity, and estimate the error due to noise and time-variability to be under 30 percent of the measured velocity. Our forward flow models are obtained by solving the Stokes flow equations using the finite-element method. We explore a range of rheological parameters, including the lava's apparent viscosity, the power-law exponent m and the thermal activation energy. We find that for the high-temperature portion of

  20. Fractal dimension analyses of lava surfaces and flow boundaries

    NASA Technical Reports Server (NTRS)

    Cleghorn, Timothy F.

    1993-01-01

    An improved method of estimating fractal surface dimensions has been developed. The accuracy of this method is illustrated using artificially generated fractal surfaces. A slightly different from usual concept of linear dimension is developed, allowing a direct link between that and the corresponding surface dimension estimate. These methods are applied to a series of images of lava flows, representing a variety of physical and chemical conditions. These include lavas from California, Idaho, and Hawaii, as well as some extraterrestrial flows. The fractal surface dimension estimations are presented, as well as the fractal line dimensions where appropriate.

  1. Recent flood lavas in the Elysium region of Mars

    NASA Technical Reports Server (NTRS)

    Plescia, J. B.

    1990-01-01

    A volcanic origin is presently suggested for the 'Cerberus Formation' region of smooth plains in the southeastern Elysium region of Mars, on the basis of its surface morphology, lobate edges, vents, and an embayment relation of the unit with adjacent, older units. The low viscosity lavas that filled a topographic depression in southeastern Elysium subsequently flowed into western Amazonic Planitia via channels formed by an earlier fluvial episode. A young, upper Amazonian dating is indicated by crater frequencies and stratigraphic relations, implying that large-scale eruptions of low-viscosity lava were still possible late in Martian history.

  2. Getting Rid of Bed Bugs

    MedlinePlus

    ... Bed Bugs — Do-it-yourself Bed Bug Control — Pesticides to Control Bed Bugs Bed Bug Information Clearinghouse ... Greener Living Health and Safety Land and Cleanup Pesticides Waste Water Science & Technology Air Climate Change Ecosystems ...

  3. Morphology and evolution of sulphuric acid caves in South Italy

    NASA Astrophysics Data System (ADS)

    D'Angeli, Ilenia M.; De Waele, Jo; Galdenzi, Sandro; Madonia, Giuliana; Parise, Mario; Vattano, Marco

    2016-04-01

    Sulphuric acid speleogenesis (SAS) related to the upwelling of acid water enriched in H2S and CO2 represents an unusual way of cave development. Since meteoric infiltration waters are not necessarily involved in speleogenesis, caves can form without the typical associated karst expressions (i.e. dolines) at the surface. The main mechanism of sulphuric acid dissolution is the oxidation of H2S (Jones et al., 2015) which can be amplified by bacterial mediation (Engel et al., 2004). In these conditions, carbonate dissolution associated with gypsum replacement, is generally believed to be faster than the normal epigenic one (De Waele et al., 2016). In Italy several SAS caves have been identified, but only few systems have been studied in detail: Frasassi and Acquasanta Terme (Marche)(Galdenzi et al., 2010), Monte Cucco (Umbria) (Galdenzi & Menichetti, 1995), and Montecchio (Tuscany) (Piccini et al., 2015). Other preliminary studies have been carried out in Calabria (Galdenzi, 2007) and Sicily (De Waele et al., 2016). Several less studied SAS cave systems located in South Italy, and in particular in Apulia (Santa Cesarea Terme), Sicily (Acqua Fitusa, Acqua Mintina) and Calabria (Mt. Sellaro and Cassano allo Ionio) have been selected in the framework of a PhD thesis on SAS caves and their speleogenesis. Using both limestone tablet weight loss (Galdenzi et al., 2012) and micro erosion meter (MEM) (Furlani et al., 2010) methods the dissolution rate above and under water in the caves will be quantified. Geomorphological observations, landscape analysis using GIS tools, and the analysis of gypsum and other secondary minerals (alunite and jarosite) (stable isotopes and dating) will help to reconstruct the speleogenetic stages of cave formation. Preliminary microbiological analysis will determine the microbial diversity and ecology in the biofilms. References Engel S.A., Stern L.A., Bennett P.C., 2004 - Microbial contributions to cave formation: New insight into sulfuric acid

  4. Field Measurements of the 1983 Royal Gardens Lava Flows, Kilauea Volcano, and 1984 Mauna Loa Lava Flow, Hawaii

    NASA Technical Reports Server (NTRS)

    Fink, J.; Zimbelman, J.

    1985-01-01

    Theoretical models used in the remote determination of lava flow rheology and compositions rely on estimates of such geometric and flow parameters as volume flow rates, levee heights, and channel dimensions, as well as morphologic and structural patterns on the flow surfaces. Quantitative measures of these variables are difficult to obtain, even under optimum conditions. Detailed topographic profiles across several Hawaiian lava flows that were carefully monitored by the U.S. Geological Survey during their emplacement in 1983 were surveyed in order to test various flow emplacement models. Twenty two accurate channel cross sections were constructed by combining these profiles with digitized pre-flow topographic measurements. Levee heights, shear zone widths, and flow depths could then be read directly from the cross sections and input into the models. The profiles were also compared with ones constructed for some Martian lava flows.

  5. Spotted hyena and steppe lion predation behaviours on cave bears of Europe - ?Late Quaternary cave bear extinction as result of predator stress

    NASA Astrophysics Data System (ADS)

    Diedrich, Cajus G.

    2010-05-01

    Cave bears hibernated in caves all over Eurasia (e.g. Rabeder et al., 2000) including alpine regions using mainly larger caves for this purpose. Late Quaternary spotted hyenas Crocuta crocuta spelaea instead occupied mainly areas close to the cave entrances as their dens (Diedrich and Žák 2006, Diedrich 2010). The largest predator, the steppe lion Panthera leo spelaea was only a sporadic cave dweller (Diedrich 2007b, 2009b). His presence and its remains from caves all over Europe can be recently explained best as result of imported carcasses after killing by their largest antagonists, the Late Quaternary spotted hyenas. In some cases the kill might have happened in the hyena den cave itself during the theft of prey remains by lions (Diedrich 2009a). Another reason of their remains in caves of Europe is the hunting onto the herbivorous cave bears, especially during hibernation times, when megafauna prey was less available in the open environments (Diedrich 2009c). These lion remains from caves of Europe, nearly all of which were from adult animals, provide evidence of active predation by lions onto cave bears even in medium high alpine regions (Diedrich 2009b, in review). Lion skeletons in European cave bear dens were therefore often found amongst originally articulated cave bear skeletons or scattered cave bear remains and even close to their hibernation nests (Diedrich et al. 2009c, in review). Not only lions fed on cave bears documented mainly by the large quantities of chewed, punctured and crushed cave bear long-bones; even damaged skulls reveal that hyenas scavenged primarily on cave bear carcasses which were mainly responsible for the destruction of their carcasses and bones (Diedrich 2005, 2009d). Predation and scavenging on cave bears by the two largest Late Quaternary predators C. c. spelaea and P. l. spelaea explains well the large quantity of fragmented cave bear bones over all European caves in low to medium high mountainous elevations, whereas in

  6. Carbon dioxide seasonality in dynamically ventilated caves: the role of advective fluxes

    NASA Astrophysics Data System (ADS)

    Lang, Marek; Faimon, Jiří; Godissart, Jean; Ek, Camille

    2016-07-01

    The seasonality in cave CO2 levels was studied based on (1) a new data set from the dynamically ventilated Comblain-au-Pont Cave (Dinant Karst Basin, Belgium), (2) archive data from Moravian Karst caves, and (3) published data from caves worldwide. A simplified dynamic model was proposed for testing the effect of all conceivable CO2 fluxes on cave CO2 levels. Considering generally accepted fluxes, i.e., the direct diffusive flux from soils/epikarst, the indirect flux derived from dripwater degassing, and the input/output fluxes linked to cave ventilation, gives the cave CO2 level maxima of 1.9 × 10-2 mol m-3 (i.e., ˜ 440 ppmv), which only slightly exceed external values. This indicates that an additional input CO2 flux is necessary for reaching usual cave CO2 level maxima. The modeling indicates that the additional flux could be a convective advective CO2 flux from soil/epikarst driven by airflow (cave ventilation) and enhanced soil/epikarstic CO2 concentrations. Such flux reaching up to 170 mol s-1 is capable of providing the cave CO2 level maxima up to 3 × 10-2 mol m-3 (70,000 ppmv). This value corresponds to the maxima known from caves worldwide. Based on cave geometry, three types of dynamic caves were distinguished: (1) the caves with the advective CO2 flux from soil/epikarst at downward airflow ventilation mode, (2) the caves with the advective soil/epikarstic flux at upward airflow ventilation mode, and (3) the caves without any soil/epikarstic advective flux. In addition to CO2 seasonality, the model explains both the short-term and seasonal variations in δ13C in cave air CO2.

  7. Internal cave gating for protection of colonies of the endangered gray bat (Myotis grisescens)

    USGS Publications Warehouse

    Martin, K.W.; Leslie, David M., Jr.; Payton, M.E.; Puckette, William L.; Hensley, S.L.

    2003-01-01

    Persistent human disturbance is a major cause for the decline in populations of many cave-dwelling bats and other sensitive cave-obligate organisms. Cave gating has been used to climinate human disturbance, but few studies have assessed directly the impact of such management activities on resident bats. In northeastern Oklahoma, USA, 25 entrances of caves inhabited by two endangered species and one endangered subspecies of bats are protected from human entry with internal gates. Because cave gates may impede ingress and egress of bats at caves, we evaluated the impacts of internal gates before and after their construction at six colonies of endangered gray bats (Myotis grisescens) from 1981 to 2001. No caves were abandoned by gray bats after the construction of internal gates; in fact, total numbers of gray bats using the six caves increased from 60,130 in 1981 to 70,640 in 2001. Two caves harbored more gray bats after gating, and three caves had no change in gray bat numbers after gating. We also compared initiations of emergences at three gated and three open-passage caves in June and July 1999-2000. No differences in timing of initiation of emergence were found between colonies in gated versus open-passage caves. Our results support the use of internal gates to protect and thereby enhance recovery of colonies of endangered gray bats. Additional research is encouraged to confirm that our observations on gray bats are generally applicable to other species of cave-dwelling bats.

  8. Numerical simulation of formation and preservation of Ningwu ice cave, Shanxi, China

    NASA Astrophysics Data System (ADS)

    Yang, S.; Shi, Y.

    2015-10-01

    Ice caves exist in locations where annual average air temperature is higher than 0 °C. An example is Ningwu ice cave, Shanxi Province, the largest ice cave in China. In order to quantitatively investigate the mechanism of formation and preservation of the ice cave, we use the finite-element method to simulate the heat transfer process at this ice cave. There are two major control factors. First, there is the seasonal asymmetric heat transfer. Heat is transferred into the ice cave from outside very inefficiently by conduction in spring, summer and fall. In winter, thermal convection occurs that transfers heat very efficiently out of the ice cave, thus cooling it down. Secondly, ice-water phase change provides a heat barrier for heat transfer into the cave in summer. The calculation also helps to evaluate effects of global warming, tourists, colored lights, climatic conditions, etc. for sustainable development of the ice cave as a tourism resource. In some other ice caves in China, managers have installed airtight doors at these ice caves' entrances with the intention of "protecting" these caves, but this in fact prevents cooling in winter and these cave ices will entirely melt within tens of years.

  9. Mount St. Helens Lava Domes, Then and Now

    NASA Astrophysics Data System (ADS)

    Fink, J.; Anderson, S. W.

    2004-12-01

    When the Mount St. Helens (MSH) lava dome grew from 1980-1986, little was known about how volatiles, vesicularity or crystallinity were distributed in domes, or about overall patterns of growth. Six years of MSH observations, coupled with comparative petrologic, structural, and analog laboratory studies of domes at Soufriere of St. Vincent, Augustine, Redoubt, Merapi, Montserrat, Santiaguito, and elsewhere have provided a much better foundation for evaluating the 2004 eruptive activity. One of the main goals of the earlier studies was to differentiate intrusive processes from those operating when magma ascends near and onto the volcano's surface. Here we use some of our earlier isotopic, petrographic and remote sensing observations of textures and volatiles to speculate about the processes operating in 2004. We earlier linked variations in lava textures to degassing processes operating during ascent and emplacement. MSH lava was extruded in a relatively dense state. When the water content was high enough, hot, ductile lava beneath the quenched outer rind of the dome vesiculated during surface flow, creating a 1 to 2 meter thick scoriaceous carapace. Post-1983 lavas lacked this scoria because the dome had reached a critical size and strength, resulting in lower short-term eruption rates and extensive degassing of lava en route to the surface. Observations of a dense "fin" in October 2004 suggest that this initial dome-building magma experienced thorough degassing as it broke a new path to the crater floor. We also used hydrogen isotope analyses of water in 1980-86 dome samples to infer degassing processes occurring in the source magma chamber and conduit system. Water content and hydrogen isotopic values of dome samples varied according to texture, position on the flow, and repose period prior to eruption. We saw two trends: (1) lava from lobes emplaced after longer repose intervals were deuterium-enriched, and (2) within individual lobes, relatively dry, smooth

  10. Ancient human footprints in Ciur-Izbuc Cave, Romania.

    PubMed

    Webb, David; Robu, Marius; Moldovan, Oana; Constantin, Silviu; Tomus, Bogdan; Neag, Ionel

    2014-09-01

    In 1965, Ciur-Izbuc Cave in the Carpathian Mountains of Romania was discovered to contain about 400 ancient human footprints. At that time, researchers interpreted the footprints to be those of a man, woman and child who entered the cave by an opening which is now blocked but which was usable in antiquity. The age of the prints (≈10-15 ka BP) was based partly on their association with cave bear (Ursus spelaeus) footprints and bones, and the belief that cave bears became extinct near the end of the last ice age. Since their discovery, the human and bear evidence and the cave itself have attracted spelunkers and other tourists, with the result that the ancient footprints are in danger of destruction by modern humans. In an effort to conserve the footprints and information about them and to reanalyze them with modern techiques, Ciur-Izbuc Cave was restudied in summer of 2012. Modern results are based on fewer than 25% of the originally described human footprints, the rest having been destroyed. It is impossible to confirm some of the original conclusions. The footprints do not cluster about three different sizes, and the number of individuals is estimated to be six or seven. Two cases of bears apparently overprinting humans help establish antiquity, and C-14 dates suggest a much greater age than originally thought. Unfortunately, insufficient footprints remain to measure movement variables such as stride length. However, detailed three-dimensional mapping of the footprints does allow a more precise description of human movements within the cave. PMID:25043334

  11. Radon in Ingleborough / Clapham Cave, North Yorkshire, UK.

    NASA Astrophysics Data System (ADS)

    Gillmore, Gavin

    2015-04-01

    Atmospheric radon concentration was measured at Ingleborough Cave, North Yorkshire during the summer of 2004, and the autumn / winter of 2004/5. Significantly, Ingleborough Cave forms part of a larger system which includes the world famous Gaping Gill pothole. This plunges 105 m (334 ft), contains the tallest unbroken waterfall in England and one of the largest known underground chambers in the UK. Measurements were taken to assess the effects of seasonal and spatial variation, elevation and ventilation on radon concentration in Ingleborough. In this study personal dose exposures for three groups of cave user were identified, and the performance of a variety of radon detection systems evaluated. Summer radon concentrations inside the cave peaked at around 7,000 Bq m-3, although average concentrations were less than 5,000 Bq m-3. During the winter measurement period, average concentrations were around 100 Bq m-3, and a winter / summer ration therefore of 47,4. The average annual radon concentration exceeded the legislative limitations for the workplace of 400 Bq m-3 due in part to a failed fan in the ventilation system. When the fan was running we noted an 80% reduction in radon concentrations although reliability of the fan was problematic due to extensive but relatively rare flooding of the cave system. The radon dose experienced by cave workers and guides in this study exceeded the Ionisation Radiation Regulations limit of 5 mSv/annum, and highlighted that for health and safety reasons the ventilation system should be fully operational during the high radon concentration summer months. Keywords: Radon, Cave, Ingleborough, Detection methods

  12. Flow Classification and Cave Discharge Characteristics in Unsaturated Karst Formation

    NASA Astrophysics Data System (ADS)

    Mariethoz, G.; Mahmud, K.; Baker, A.; Treble, P. C.

    2015-12-01

    In this study we utilize the spatial array of automated cave drip monitoring in two large chambers of the Golgotha Cave, SW Australia, developed in Quaternary aeolianite (dune limestone), with the aim of understanding infiltration water movement via the relationships between infiltration, stalactite morphology and groundwater recharge. Mahmud et al. (2015) used the Terrestrial LiDAR measurements to analyze stalactite morphology and to characterize possible flow locations in this cave. Here we identify the stalactites feeding the drip loggers and classify each as matrix (soda straw or icicle), fracture or combined-flow. These morphology-based classifications are compared with flow characteristics from the drip logger time series and the discharge from each stalactite is calculated. The total estimated discharge from each area is compared with infiltration estimates to better understand flow from the surface to the cave ceilings of the studied areas. The drip discharge data agrees with the morphology-based flow classification in terms of flow and geometrical characteristics of cave ceiling stalactites. No significant relationships were observed between the drip logger discharge, skewness and coefficient of variation with overburden thickness, due to the possibility of potential vadose-zone storage volume and increasing complexity of the karst architecture. However, these properties can be used to characterize different flow categories. A correlation matrix demonstrates that similar flow categories are positively correlated, implying significant influence of spatial distribution. The infiltration water comes from a larger surface area, suggesting that infiltration is being focused to the studied ceiling areas of each chamber. Most of the ceiling in the cave site is dry, suggesting the possibility of capillary effects with water moving around the cave rather than passing through it. Reference:Mahmud et al. (2015), Terrestrial Lidar Survey and Morphological Analysis to

  13. Paleo-watertable definition using cave ferromanganese stromatolites and associated cave-wall notches (Sierra de Arnero, Spain)

    NASA Astrophysics Data System (ADS)

    Rossi, Carlos; Villalaín, Juan J.; Lozano, Rafael P.; Hellstrom, John

    2016-05-01

    The steeply-dipping-dolostone-hosted caves of the Sierra de Arnero (N Spain) contain low-gradient relict canyons with up to ten mapped levels of ferromanganese stromatolites and associated wall notches over a vertical range of 85 m, the highest occurring ~ 460 m above base level. Despite a plausible speleogenetic contribution by pyrite oxidation, and the irregular cave-wall mesomorphologies suggestive of hypogenic speleogenesis, the Arnero relict caves are dominantly epigenic, as indicated by the conduit pattern and the abundant allogenic sediments. Allogenic input declined over time due to a piracy-related decrease in the drainage area of allogenic streams, explaining the large size of the relict Arnero caves relative to the limited present-day outcrop area of the karstified carbonates. Allogenic-sediment input also explains the observed change from watertable canyons to phreatic conduits in the paleo-downstream direction. Stromatolites and notches arguably formed in cave-stream passages at the watertable. The best-defined paleo-watertables show an overall slope of 1.7°, consistent with the present-day relief of the watertable, with higher-slope segments caused by barriers related to sulfide mineralization. The formation of watertable stromatolites favored wall notching by the combined effect of enhanced acidity by Mn-Fe oxidation and shielding of cave floors against erosion. Abrasive bedload further contributed to notch formation by promoting lateral mechanical erosion and protecting passage floors. The irregular wallrock erosional forms of Arnero caves are related partly to paragenesis and partly to the porous nature of the host dolostones, which favored irregular dissolution near passage walls, generating friable halos. Subsequent mechanical erosion contributed to generate spongework patterns. The dolostone porosity also contributes to explain the paradox that virtually all Arnero caves are developed in dolostone despite being less soluble than adjacent

  14. Experiments on Natural-Scale Basaltic Lava Flows: Scope and First Results of the Syracuse University Lava Project

    NASA Astrophysics Data System (ADS)

    Karson, J.; Wysocki, R.; Kissane, M. T.; Smith, C.; Spencer, S.

    2012-12-01

    The Syracuse University Lava Project creates natural-scale basaltic lava flows for scientific investigations, educational opportunities and artistic projects. Modified furnaces designed for melting and pouring metals are used to create individual basaltic lava flow lobes of up to 450 kg (10-2m2) with the potential to generate much larger flow fields under controlled conditions. At present, the starting material used in 1.1 Ga Keewenan basalt from the Mid-Continent Rift in NW Wisconsin, a relatively uniform, well-characterized tholeiitic-alkalic basalt. Other compositions (andesite, komatiite, carbonatite) are planned for future experiments. Basaltic gravel is heated to 1100° to 1300°C in a crucible resulting in homogeneous, convecting basaltic magma. Lava is poured over a variety of surfaces including rock slabs, wet or dry sand, H2O or CO2 ice, rough or smooth material, and confined or unconfined channels. Resulting lava flows can be dissected for mapping details of morphological and textural variations. Video from various perspectives is used to document flow behavior and evolution. Infrared images constrain flow temperatures. Textural features of flows such as vesicles and plagioclase microlites have vertical and lateral variations similar to those of natural flows. Differing experimental set-ups provide analogs for a wide range of terrestrial, marine, and extraterrestrial lava flows. In an initial series of experiments, basaltic lava flows (50-200 kg) were poured over dry sand at near constant effusion rates (~10-4m3s-1). Flow temperature and slope were varied to produce a range of different flow morphologies. The results show systematic behavior consistent with observations of natural lava flows and analog experiments. At relatively high T (>1200°C) and steeper slopes (>15°) thin, narrow, leveed flows form. At intermediate T and slope, sheet-like, ropey, pahoehoe forms develop. Flows at the lowest T (1100°C) and gentlest slopes (<10°) investigated

  15. A roadmap to cave dwelling on the Moon and Mars

    NASA Astrophysics Data System (ADS)

    Blamont, Jacques

    2014-11-01

    Habitat in lava tubes recently discovered on the Moon and Mars, should become a unifying concept for occupancy. Basic motivations and specifications for such a habitat are briefly reviewed. The first step is to obtain a consensus from Agencies on the validity of the concept. Afterwards, two types of research programs should be implemented: Search for lava tubes by dedicated polar orbiters.Mapping, classification and choice of site should be achieved before 2020. Development of specific technology to begin by the end of the 2020s: Bulldozers, elevators, and cranes for access. Inflatable cylindrical structures of large dimension for housing. Since apprenticeship is needed for Mars habitat, Moon lava tubes would be used as a first step. Use of lava tubes provides therefore a unifying concept for exploration. A roadmap is proposed.

  16. Pleistocene cave art from Sulawesi, Indonesia.

    PubMed

    Aubert, M; Brumm, A; Ramli, M; Sutikna, T; Saptomo, E W; Hakim, B; Morwood, M J; van den Bergh, G D; Kinsley, L; Dosseto, A

    2014-10-01

    Archaeologists have long been puzzled by the appearance in Europe ∼40-35 thousand years (kyr) ago of a rich corpus of sophisticated artworks, including parietal art (that is, paintings, drawings and engravings on immobile rock surfaces) and portable art (for example, carved figurines), and the absence or scarcity of equivalent, well-dated evidence elsewhere, especially along early human migration routes in South Asia and the Far East, including Wallacea and Australia, where modern humans (Homo sapiens) were established by 50 kyr ago. Here, using uranium-series dating of coralloid speleothems directly associated with 12 human hand stencils and two figurative animal depictions from seven cave sites in the Maros karsts of Sulawesi, we show that rock art traditions on this Indonesian island are at least compatible in age with the oldest European art. The earliest dated image from Maros, with a minimum age of 39.9 kyr, is now the oldest known hand stencil in the world. In addition, a painting of a babirusa ('pig-deer') made at least 35.4 kyr ago is among the earliest dated figurative depictions worldwide, if not the earliest one. Among the implications, it can now be demonstrated that humans were producing rock art by ∼40 kyr ago at opposite ends of the Pleistocene Eurasian world. PMID:25297435

  17. Field test of a calcite dissolution rate law: Fort's Funnel Cave, Mammoth Cave National Park

    SciTech Connect

    Slunder, J.S. ); Groves, C.G. . Center for Cave and Karst Studies)

    1994-03-01

    The laboratory-derived calcite dissolution rate law of Plummer et al. (1978) is the most widely used and mechanistically detailed expression currently available for predicting dissolution rates as a function of water chemistry. Such rate expressions are of great use in understanding timescales associated with limestone karst development. Little work has gone into the field testing of the rate law under natural conditions. This work measured dissolution rates by a crystal weight loss experiment in Buffalo Creek within Fort's funnel Cave, which lies within a pristine, forested catchment of Mammoth Cave National Park. Continuous water chemistry sampling over the same period allowed a time-integrated prediction of the dissolution based on the Plummer et al. (1978) expression. Results indicate that the rate law overpredicted dissolution by a factor of about ten. This concurs with earlier laboratory work suggesting that the law tends to overpredict rates in solutions close to equilibrium with respect to calcite, as were the waters within this part of the groundwater flow system.

  18. A prototype mass spectrometer for in situ analysis of cave atmospheres

    NASA Astrophysics Data System (ADS)

    Patrick, Edward L.; Mandt, Kathleen E.; Mitchell, Evelynn J.; Mitchell, Joseph N.; Younkin, Kerri N.; Seifert, Clarissa M.; Williams, Gregg C.

    2012-10-01

    Research in cave environments has many applications: studying local hydrogeologic activity, paleoclimate studies, analyzing white nose syndrome in bat populations, analogs for underground atmospheres in mining facilities, carbon sequestration efforts, and terrestrial analogs for planetary caves. The atmospheres of many caves contain tracers of current geological and biological activity, but up to this point, in situ studies have been limited to sensors that monitor individual components of the cave atmosphere. A prototype cave mass spectrometer system was assembled from commercial off-the-shelf parts to conduct surveys of atmospheric compositions inside four local Texas caves and to perform atmospheric analysis of two aquifer wellheads to a depth of 60 m. We found increased levels of CO2 in all caves and, surprisingly, increased levels of O2 in Bracken Bat Cave. Aquifer wellhead measurements showed indications of methane, other hydrocarbons, and other constituents not anticipated.

  19. Geomicrobiology of Phreatic Caves Associated With Central Florida Springs

    NASA Astrophysics Data System (ADS)

    Giannotti, A. L.; Tysall, T. N.; Franklin, R. B.; Mills, A. L.

    2005-05-01

    Phreatic (underwater) limestone caves are common in Florida in association with the numerous springs that issue from the karst landscape. Extensive microbial mats and diverse communities of invertebrates have been observed by cave divers, but, as ecosystems, the caves are not well studied. Four aphotic aquatic caves were identified in which to investigate relationships between microbial communities and their geochemical surroundings, and to evaluate the potential for chemolithoautotrophic microbial activity to support higher-order consumers. The caves were associated with the discharge sites of four different second-magnitude springs (flow: 0.3 to 3 m3 s-1) in central Florida in which communities containing microbial mats, isopods, amphiphods, and cave crayfish have been observed. Samples of bulk water and microbial mat were collected along the flow path in each cave; depths ranged from 0.5 to 15 m below the ground surface, and penetration distance extended up to 250 m from each cave entrance. Microscopic examination of the mats revealed the presence of sulfur-granule-containing, filamentous morphologies consistent with Thiothrix and Beggiatoa and an unidentified filamentous iron bacteria. The bacteria were found in all four springs, but H2S was detected in water samples from only one of the caves. In many cases, the morphology of the organisms changed along the flow path within an individual spring, although there was little change in the associated water chemistry (pH, dissolved oxygen, conductivity, total Fe, NH4+, NO3-, HS-, SO42-, PO4-, Cl-, Fl-, Ca2+, Na+, and Mg2+). The overall water chemistry of the four caves/springs was distinct (principal components analysis), and the major differences were due to Ca2+, K+, and Cl- concentrations, pH (range: 7.3 to 8.4), and sulfur and iron availability. Efforts to culture the dominant organisms in each set of mats (using media prepared with cave or spring water) and community-level genetic analyses (T-RFLP) demonstrated

  20. Lava flow materials in the Tharsis region of Mars

    NASA Technical Reports Server (NTRS)

    Schaber, G. G.; Horstman, K. C.; Dial, A. L., Jr.

    1978-01-01

    Lava-flow materials in the Tharsis region of Mars were studied from moderate-resolution (100-280 m/pixel) Viking Orbiter imagery. Individual eruptive sequences were recognized primarily by stratigraphic relations, density of superimposed impact craters, flow morphology, flow trend, and variations in surface albedo. Nine detailed maps of lava flows based on delineation of flow scarps were compiled for a total area of 7.25 million sq km. Two thirds of this area was covered by mappable flows representing at least 14 distinct eruptive sequences. Assuming a rate of crater production twice that of the moon, the observed range of superimposed crater densities (90 to 3200 craters at least 1 km in diameter per sq km) indicates an age range of 100 m.y. to several billion years for these flows. The youngest lavas are associated with flood lavas filling the depression surrounding the Olympus Mons shield. Flow thicknesses range from less than 5 meters to 20 meters on steeper shield slopes (0.5 to 4.5 deg) and from 20 to 65 meters on relatively flat (less than 0.5 deg slope) terrain.

  1. A Radiation Safety Analysis for Lunar Lava Tubes

    NASA Technical Reports Server (NTRS)

    DeAngelis, G.; Wilson, J. W.; Clowdsley, M. S.; Nealy, J. E.; Humes, D. H.; Clem, J. M.

    2002-01-01

    The purpose of this work is an assessment of the lunar lava tubes physical characteristics and an evaluation of the their actual safety features from the point of view of the ionizing radiation environment as potential habitats for future lunar exploration crews. Additional information is contained in the original extended abstract.

  2. Fluctuating supply and emplacement dynamic of channelized lava flows

    NASA Astrophysics Data System (ADS)

    Tarquini, Simone; de'Michieli Vitturi, Mattia

    2014-05-01

    The evolution of lava flows emplaced on Mount Etna (Italy) in September 2004 is examined in detail through the analysis of morphometric measurements of flow units. The growth of the main channelized flow is consistent with a layering of lava blankets which maintains the initial geometry of the channel (although levees are widened and raised), and is here explicitly related to the repeated overflow of lava pulses. A simple analytical model is introduced describing the evolution of the flow level in a channelized flow unit fed by a fluctuating supply. The model, named FLOWPULSE, shows that a fluctuation in the velocity of lava extrusion at the vent triggers the formation of pulses which become increasingly high the farther they are from the vent, and are invariably destined to overflow within a given distance. The FLOWPULSE simulations are in accordance with the observed morphology, characterized by a very flat initial profile followed by a massive increase in flow unit cross-section area between 600 and 700 m downflow. The modeled emplacement dynamics provides also an explanation for the observed substantial "loss" of the original flowing mass with increasing distance from the vent.

  3. OVEN & LAVA Subsystems in the RESOLVE Payload for Resource Prospector

    NASA Technical Reports Server (NTRS)

    Captain, Janine E.

    2015-01-01

    A short briefing in Power Point of the status of the OVEN subsystem and the LAVA subsystems of the RESOLVE payload being developed under the Resource Prospector mission. The purpose of the mission is to sample and analyze volatile ices embedded in the lunar soil at the poles of the Moon and is expected to be conducted in the 2020 time frame.

  4. Raman Study of Secondary Minerals in a Recent Lava Tube

    NASA Astrophysics Data System (ADS)

    Guimbretière, G.; Canizarès, A.; Finizola, A.; Delcher, E.; Raimboux, N.; Veron, E.; Simon, P.; Devouard, B.; Bertil, A.

    2014-06-01

    We present here the technical adaptations made for a field use of a laboratory in situ Raman spectrometer, and the characterization of secondary mineral phases growing in a recent, still hot on some spots, lava tube (2007 Piton de la Fournaise).

  5. Lava Lakes on Io: New Perspectives from Modeling

    NASA Technical Reports Server (NTRS)

    Gregg, Tracy K. P.; Lopes, Rosaly M.

    2004-01-01

    Ionian paterae are a class of volcanic feature that are characterized by irregular craters with steep walls, flat floors, and arcuate margins that may or may not exhibit nesting. Loki (310 W, 12 N) is Io's largest patera at approx.200 km in diameter (Figure 1), and may account for 15% of Io's total heat flow. Earth-based infrared data, as well as information collected using the Galileo Near-Infrared Mapping Spectrometer (NIMS) and the Photopolarimeter Radiometer (PPR) have been used to interpret Loki s eruption style. Debate continues over whether Loki s occasional (periodic or not) temperature increases are due to an overturning lava lake within the patera, or to an eruption of surface flows on the patera floor. Interpretation of model results and comparisons with active terrestrial lava lakes suggest that Loki behaves quite differently from active lava lakes on Earth, and that surface flows (rather than an overturning lava lake) are a more likely explanation of Loki's thermal brightening.

  6. Oblique view of the northeast side, note the lava rock ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique view of the northeast side, note the lava rock stem wall below the windows of the shed-roof addition, view facing west - U.S. Marine Corps Base Hawaii, Kaneohe Bay, Golf Course Equipment & Repair Shop, Reeves & Moffett Roads, Kaneohe, Honolulu County, HI

  7. The CAVE (TM) automatic virtual environment: Characteristics and applications

    NASA Technical Reports Server (NTRS)

    Kenyon, Robert V.

    1995-01-01

    Virtual reality may best be defined as the wide-field presentation of computer-generated, multi-sensory information that tracks a user in real time. In addition to the more well-known modes of virtual reality -- head-mounted displays and boom-mounted displays -- the Electronic Visualization Laboratory at the University of Illinois at Chicago recently introduced a third mode: a room constructed from large screens on which the graphics are projected on to three walls and the floor. The CAVE is a multi-person, room sized, high resolution, 3D video and audio environment. Graphics are rear projected in stereo onto three walls and the floor, and viewed with stereo glasses. As a viewer wearing a location sensor moves within its display boundaries, the correct perspective and stereo projections of the environment are updated, and the image moves with and surrounds the viewer. The other viewers in the CAVE are like passengers in a bus, along for the ride. 'CAVE,' the name selected for the virtual reality theater, is both a recursive acronym (Cave Automatic Virtual Environment) and a reference to 'The Simile of the Cave' found in Plato's 'Republic,' in which the philosopher explores the ideas of perception, reality, and illusion. Plato used the analogy of a person facing the back of a cave alive with shadows that are his/her only basis for ideas of what real objects are. Rather than having evolved from video games or flight simulation, the CAVE has its motivation rooted in scientific visualization and the SIGGRAPH 92 Showcase effort. The CAVE was designed to be a useful tool for scientific visualization. The Showcase event was an experiment; the Showcase chair and committee advocated an environment for computational scientists to interactively present their research at a major professional conference in a one-to-many format on high-end workstations attached to large projection screens. The CAVE was developed as a 'virtual reality theater' with scientific content and

  8. Fire and Ice: Lavas on Io, Cryolavas on Titan

    NASA Astrophysics Data System (ADS)

    Lopes, R. M.; Gregg, T. K.; Spencer, J. R.; Mitchell, K. L.; Williams, D. A.

    2007-12-01

    Volcanic flows in our solar system are remarkably varied. Io and Titan are particularly good examples of relatively large bodies that have erupted a variety of flows, ranging from basaltic and possibly sulfur and ultramafic lavas on Io to mixtures of water and possibly ammonia and methanol on Titan. These exotic extraterrestrial flows can be much different from the examples we see on Earth, but the similarities are also striking. Understanding their eruption mechanisms is important for better constraining how effusive eruptions behave on Earth under present and past conditions. Io has exceptionally long lava flows, but these are rare compared to the most common form of Ionian volcanism; lava lakes and lava flows that are confined within calderas [Lopes et al., 2004, Icarus; Gregg and Lopes, Icarus, in press]. The largest lava flows on Io can be considered analogues to continental flood basalts on Earth, being hundreds of km long and containing many different flow units. The composition of these flows on Io is thought to be either basaltic or ultramafic. Galileo results showed the largest active flow in the Solar System at Amirani [300 km long; Kezthelyi et al., 2001, JGR 106] and recent observations by the New Horizons spacecraft showed a new flow at Masubi that is about 200 km long. Ionian flows at volcanoes such as Masubi, Maui, and Prometheus generate persistently active plumes and the movement of the Prometheus plume has been related to the growth of the lava flow [Kieffer et al. 2000, Science 288]. Sulfur flows are thought to exist on Io, but are largely a by-product of silicic volcanism. On Earth, sulfur flows are rare but have formed from melting hydrothermal sulfur deposits. Flows around Emakong on Io are thought to be sulfur flows [Williams et al., 2001, JGR 106], but to date there are no measurements that can confirm their composition. Ra Patera's flows at the time of the Voyager encounter was thought to be a site of sulfur volcanism [Pieri et al., 1984

  9. Rheology of lava flows on Mercury: an experimental study

    NASA Astrophysics Data System (ADS)

    Sehlke, A.; Whittington, A. G.

    2014-12-01

    The morphology of lava flows is controlled by the physical properties of the lava and its effusion rates, as well as environmental influences such as surface medium, slope and ambient temperature and pressure conditions. The important rheological properties of lavas include viscosity (η) and yield strength (σy), strongly dependent on temperature (T), composition (X), crystal fraction (φc) and vesicularity (φb). The crystal fraction typically increases as temperature decreases, and also influences the residual liquid composition. The rheological behavior of multi-phase lava flows is expressed as different flow morphologies, for example basalt flows transition from smooth pahoehoe to blocky `a`a at higher viscosities and/or strain rates. We have previously quantified the rheological conditions of this transition for Hawaiian basalts, but lavas on Mercury are very different in composition and expected crystallization history. Here we determine experimentally the temperature and rheological conditions of the pahoehoe-`a`a transition for two likely Mercury lava compositions using concentric cylinder viscometry. We detect first crystals at 1302 ºC for an enstatite basalt and 1317 ºC for a basaltic komatiite composition representative of the northern volcanic plains (NVP). In both cases, we observe a transition from Newtonian to pseudo-plastic response at crystal fractions > 10 vol%. Between 30 to 40 vol%, a yield strength (τ0) around 26±6 and 110±6 Pa develops, classifying the two-phase suspensions as Herschel-Bulkley fluids. The measured increase in apparent viscosity (ηapp) ranges from 10 Pa s to 104 Pa s. This change in rheological properties occurs only in a temperature range up to 100 ºC below the liquidus. By analogy with the rheological conditions of the pahoehoe-`a`a transition for Hawaiian basalts, we can relate the data for Mercury to lava flow surface morphology as shown in Figure 1, where the onset of the transition threshold zone (TTZ) for the

  10. Use of VNIR Camera System to Estimate Lava Temperature

    NASA Astrophysics Data System (ADS)

    Vaughan, R.; Keszthelyi, L. P.

    2012-12-01

    We present initial results from using a visible and near infrared (VNIR) camera as an optical pyrometer at Kilauea Volcano, Hawai`i. The basic concept of pyrometry simply converts the color of incandescent material into a temperature and has been used on Kilauea since the earliest days of regular volcano monitoring. However, these temperatures have always been lower than expected, raising the concern that the emissivity of lava at these wavelengths was not close to a blackbody. We carefully calibrated a system that uses 3 digital cameras with wavelengths similar to the green, red, and near-infrared channels of the Landsat Enhanced Thematic Mapper plus (ETM+) and Advanced Spaceborne Thermal Emissions and Reflection Radiometer (ASTER) VNIR instruments by imaging a high-temperature blackbody. Following techniques used to estimate lava temperatures on Jupiter's moon, Io, we obtained relationships between band ratios and blackbody temperatures. The green/red ratio provides good temperature estimates for any reasonable temperature above 1000 °C, while the red/NIR is useful from about 700-1200 °C. We also observed the glow from the lava lake in Halema`uma`u as reflected and scattered from the steam plume above it. We found that the temperatures inferred from the glow are much too high (~1400 °C) from the red/NIR ratios and much too low (<700 °C) from the green/red ratios. One possible explanation is that there are variations in the emissivity of molten lava at these wavelengths. However, we also know that there are wavelength dependent scattering properties of the plume cloud that are consistent with errors in these temperature estimates. Future work examining incandescent lava without the interference of a plume will be needed to better evaluate the emissivity of lava in this wavelength range. However, we have sufficient data to demonstrate the great utility of VNIR data acquired at night for determining if a volcano is actively erupting mafic lava. We propose that

  11. Pulmonary histoplasmosis associated with exploration of a bat cave.

    PubMed

    Lottenberg, R; Waldman, R H; Ajello, L; Hoff, G L; Bigler, W; Zellner, S R

    1979-08-01

    Approximately 14 days after exploring a limestone cave in northcentral Florida in February 1973, an 18-year-old female developed a respiratory illness with pronounced shortness of breath and cyanosis. The following day, an 18-year-old male presented to the hospital with similar complaints. The association of illness with their recent caving experience prompted further epidemiologic investigation. Twenty-nine members of a church-sponsored youth group explored the implicated cave. Twenty-three of them later became ill with complaints of cough, afternoon fever and sweats, chest discomfort, and dyspnea on exertion. Histoplasmin skin tests were positive in 18 of 24 individuals tested. Serum for complement fixation (CF) was positive in 12 of 26. Testing of area residents revealed a low incidence of skin test and CF positivity (7% and 0%, respectively). That spelunkers are at risk of acquiring pulmonary histoplasmosis has been noted previously; in Florida this has been related to the exploration of caves infested with bats. This is the largest reported outbreak of acute pulmonary histoplasmosis that has been associated with spelunking and further points out that only those individuals who enter the cave are at risk of acquiring the disease, and not those who reside in the surrounding area. PMID:572635

  12. Mining safety of longwall top-coal caving in China

    SciTech Connect

    Wu, J.; Qin, Y.; Zhai, M.

    1999-07-01

    Longwall top-coal caving technology has developed rapidly in China, in recent years. The application of longwall top-coal caving can double both the productivity and the efficiency of a working face and reduce the cost of production by 30 to 50%. Using standard longwall equipment, annual production can reach 3 million metric tons (Mt), and a maximum of 4.1 Mt has been obtained; many top-coal caving longwall working faces can obtain 200 tons per man-shift. Longwall top-coal caving is distinctly different from slice mining in thicken seam. Concerns of safety and productivity for this method have been raised in recent years. This paper will discuss the following: (1) how to recognize the law of fire-damp emission, accumulation and outburst; (2) how to resolve the ventilation problem in a highly gassy working face; (3) how to recognize the law of spontaneous combustion of ignitable coal, and to avoid spontaneous combustion in gob area; and (4) how to control dust in longwall top-coal caving face.

  13. The setting of the Mt. Carmel caves reassessed

    NASA Astrophysics Data System (ADS)

    Vita-Finzi, Claudio; Stringer, Chris

    2007-02-01

    Four caves on the SW flank of Mt. Carmel, es Skhul, el Wad, el Jaml and et Tabun, were first excavated in the 1930s by a team led by Dorothy Garrod. They yielded human remains whose age and evolutionary status remain controversial partly because the complexity of the cave deposits invites conflicting interpretations. The abrasion of artefacts and pebbles in el Wad and es Skhul, which was originally ascribed to spring flow within the caves, is explained here by wave action, with the implication that during part of the Middle Palaeolithic the caves were on the shoreline rather than being separated from it—as they now are—by several kilometres of coastal plain and a height difference of some 45 m. U-series, thermoluminescence (TL) and electron spin resonance (ESR) dating suggests that this occurred about 120,000 years ago, when sea level in the eastern Mediterranean stood 5-6 m above its present position. It follows that Mt. Carmel has subsequently undergone some 40 m of uplift. During the period of maximum submergence, the coastal route between Africa and the northern Mediterranean would have been partly blocked, but the loss of the coastal plain for transit and as a source of animal food was offset by easier access from the caves to marine resources.

  14. Transitional lava flows as potential analogues for lunar impact melts

    NASA Astrophysics Data System (ADS)

    Neish, Catherine; Hughes, Scott; Hamilton, Christopher; Kobs Nawotniak, Shannon; Garry, William Brent; Skok, John Roma; Elphic, Richard; Carter, Lynn; Bandfield, Joshua; Osinski, Gordon; Lim, Darlene; Heldmann, Jennifer

    2015-11-01

    Lunar impact melt deposits are among the roughest surface materials on the Moon at the decimeter scale, even though they appear smooth at the meter scale. These characteristics distinguish them from well-studied terrestrial analogues, such as Hawaiian pāhoehoe and ´a´ā lava flows. The morphology of impact melt deposits can be related to their emplacement conditions, so understanding the origin of these unique surface properties will inform us as to the circumstances under which they were formed. Although there is no perfect archetype for lunar impact melts on Earth, certain terrestrial environments lend themselves as functional analogues. Specifically, a variety of transitional lava flow types develop if the surface of a pāhoehoe-like flow is disrupted, producing ‘slabby’ or ‘rubbly’ flows that are extremely rough at the decimeter scale. We investigated the surface roughness of transitional lava flows at Craters of the Moon (COTM) National Monument, comparing radar imagery and high-resolution topographic profiles to similar data sets acquired by the Lunar Reconnaissance Orbiter for impact melt deposits on the Moon. Results suggest that the lava flows at COTM have similar radar properties to lunar impact melt deposits, but the terrestrial flows are considerably rougher at the meter scale. It may be that lunar impact melts represent a unique lava type not observed on Earth, whose surface texture is influenced by their high emplacement temperatures and/or cooling in a vacuum. Information about the surface properties of lunar impact melt deposits will be critical for future landed missions that wish to sample these materials.

  15. Cave levels as proxies for measuring post-orogenic uplift: Evidence from cosmogenic dating of alluvium-filled caves in the French Pyrenees

    NASA Astrophysics Data System (ADS)

    Calvet, M.; Gunnell, Y.; Braucher, R.; Hez, G.; Bourlès, D.; Guillou, V.; Delmas, M.

    2015-10-01

    The rates and chronology of valley incision in mountain ranges have been studied in various parts of the globe, but the causes of river incision are often blurred because tectonic, climatic, and sea level-related forcing signals are difficult to distinguish from one another. The Têt River limestone gorge in the Eastern Pyrenees, which displays multiple cave levels containing datable alluvial deposits, provides an opportunity for clarifying this debate. Horizontal epiphreatic passages in limestone can be used as substitutes for fluvial terraces because they correspond to former valley floors and, therefore, also record the position of former local base levels. In the Têt canyon, the passages are filled with quartz-rich sand and gravel sequences that can be dated by 26Al/10Be burial dating. The canyon has cut into a Middle Miocene pediment system-now forming a raised plateau at 1250-1500 m-and displays nine cave levels over a vertical height of 1 km. One alluvial fill sequence in a cave at + 270 m above datum (i.e., the local river bed) yielded a weighted mean age of 5.14 ± 0.41 Ma; another, situated at + 110 m above datum, yielded weighted mean ages of 2.23 ± 0.230 Ma and 1.20 ± 0.286 Ma. The data convert to a mean incision rate of ~ 52 m·Ma- 1 since the beginning of the Pliocene, and involved an acceleration to 92 m·Ma- 1 during the Quaternary. Pre-burial catchment denudation rates range from 35 to 7 m·Ma- 1, and these also doubled during the early Quaternary. It is concluded that: (i) valley incision into the Miocene pediment has been occurring since 5, probably 10 Ma; (ii) there is no evidence of a Messinian canyon in the Villefranche gorge, strongly suggesting through various additional indicators that interference of the Messinian Salinity Crisis with the canyon incision history was minimal; (iii) valley deepening was not a steady process, and recorded periods of stability around 1-2 Ma and perhaps 6-5 Ma; and (iv) the terraced network of epiphreatic

  16. Hominid exploitation of the environment and cave bear populations. The case of Ursus spelaeus Rosenmüller-Heinroth in Amutxate cave (Aralar, Navarra-Spain).

    PubMed

    Torres, Trinidad; Ortiz, José E; Cobo, Rafael; de Hoz, Pedro; García-Redondo, Ana; Grün, Rainer

    2007-01-01

    Cave bears (Ursus deningeri and U. spelaeus) and hominids (Homo heidelbergensis, H. neanderthalensis, and H. sapiens) were potential competitors for environmental resources (subterranean and open air). Here, we examined the age at death of cave bear (Ursus spelaeus Rosenmüller-Heinroth) specimens from Amutxate cave in order to shed light on the effect of resource sharing between cave bears and hominids. After studying dental wear of the deciduous and permanent dentitions, the ontogenetic development of mandibles, and incremental layers of cement (annuli), we defined five age groups differentiated by marked development and size gaps. Our findings indicate that after hibernating, bears abandoned the den, thereby leaving the subterranean environment (caves) free for temporary hominid occupation-this would explain the subtle traces of hominid presence in many dens. However, a simple calculation based on age at death of subadult and adult cave bear specimens in Amutxate cave, extrapolated to the whole cave area, showed that the area surrounding this cave hosted bears for at least 9,000 years. This length of habitation, quite similar to the time-span derived from amino acid racemization and electron spin resonance, indicates that bear populations in the Amutxate cave constituted a serious constraint for hominid exploitation of the environment. PMID:16996576

  17. Formation of perched lava ponds on basaltic volcanoes: Interaction between cooling rate and flow geometry allows estimation of lava effusion rates

    NASA Technical Reports Server (NTRS)

    Wilson, L.; Parfitt, E. A.

    1993-01-01

    Perched lava ponds are infrequent but distinctive topographic features formed during some basaltic eruptions. Two such ponds, each approximately 150 m in diameter, formed during the 1968 eruption at Napau Crater and the 1974 eruption of Mauna Ulu, both on Kilauea Volcano, Hawaii. Each one formed where a channelized, high volume flux lava flow encountered a sharp reduction of slope: the flow spread out radially and stalled, forming a well-defined terminal levee enclosing a nearly circular lava pond. We describe a model of how cooling limits the motion of lava spreading radially into a pond and compare this with the case of a channelized flow. The difference in geometry has a major effect, such that the size of a pond is a good indicator of the volume flux of the lava forming it. Lateral spreading on distal shallow slopes is a major factor limiting the lengths of lava flows.

  18. Project C.A.V.E.S.: High School Spelunking in Arkansas.

    ERIC Educational Resources Information Center

    Reese, Rachel

    1989-01-01

    Project CAVES (Creative Adventures and Valuable Experiences through Spelunking) is a summer residential program for gifted high-school students, involving lectures, surveying and mapping simulated caves, and exploring and surveying actual caves in Arkansas. The project's development and learning activities are described. (JDD)

  19. 36 CFR 290.3 - Nomination, evaluation, and designation of significant caves.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 2 2012-07-01 2012-07-01 false Nomination, evaluation, and designation of significant caves. 290.3 Section 290.3 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE CAVE RESOURCES MANAGEMENT § 290.3 Nomination, evaluation, and designation of significant caves. (a) Nominations...

  20. 36 CFR 290.3 - Nomination, evaluation, and designation of significant caves.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 2 2013-07-01 2013-07-01 false Nomination, evaluation, and designation of significant caves. 290.3 Section 290.3 Parks, Forests, and Public Property FOREST SERVICE, DEPARTMENT OF AGRICULTURE CAVE RESOURCES MANAGEMENT § 290.3 Nomination, evaluation, and designation of significant caves. (a) Nominations...

  1. Identifying Source Mixing and Examining Water Chemistry Variations: The Carroll Cave - Toronto Springs System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Located in the Missouri Ozarks, Carroll Cave is a dendritic stream cave system, formed in Ordivician Gasconade dolomite. In 2002, a new survey effort was launched under the auspices of the Carroll Cave Conservancy to provide a comprehensive map of the system. Since that time, 29.89 km of estimated p...

  2. Fluidized bed combustor modeling

    NASA Technical Reports Server (NTRS)

    Horio, M.; Rengarajan, P.; Krishnan, R.; Wen, C. Y.

    1977-01-01

    A general mathematical model for the prediction of performance of a fluidized bed coal combustor (FBC) is developed. The basic elements of the model consist of: (1) hydrodynamics of gas and solids in the combustor; (2) description of gas and solids contacting pattern; (3) kinetics of combustion; and (4) absorption of SO2 by limestone in the bed. The model is capable of calculating the combustion efficiency, axial bed temperature profile, carbon hold-up in the bed, oxygen and SO2 concentrations in the bubble and emulsion phases, sulfur retention efficiency and particulate carry over by elutriation. The effects of bed geometry, excess air, location of heat transfer coils in the bed, calcium to sulfur ratio in the feeds, etc. are examined. The calculated results are compared with experimental data. Agreement between the calculated results and the observed data are satisfactory in most cases. Recommendations to enhance the accuracy of prediction of the model are suggested.

  3. Fluidized bed combustion

    SciTech Connect

    Sowards, N.K.; Murphy, M.L.

    1991-10-29

    This patent describes a vessel. It comprises a fluid bed for continuously incinerating fuel comprising tire segments and the like which comprise metallic wire tramp and for concurrently removing tramp and bed materials at a bottom effluent exit means of the vessel, the vessel further comprising static air distributor means at the periphery of the bed comprising a substantially centrally unobstructed relatively large central region in which the fluid bed and fuel only are disposed and through which bed material and tramp migrate without obstruction to and through the effluent exit means, downwardly and inwardly stepped lower vessel wall means and a plurality of peripherally located centrally directed vertically and horizontally offset spaced air influent means surrounding the central region and associated with the stepped lower vessel wall means by which the bed is supported and fluidized.

  4. Fossil invertebrates records in cave sediments and paleoenvironmental assessments - a study of four cave sites from Romanian Carpathians

    NASA Astrophysics Data System (ADS)

    Moldovan, O. T.; Constantin, S.; Panaiotu, C.; Roban, R. D.; Frenzel, P.; Miko, L.

    2016-01-01

    Fossil invertebrates from cave sediments have been recently described as a potential new proxy for paleoenvironment and used in cross-correlations with alternate proxy records from cave deposits. Here we present the results of a fossil invertebrates study in four caves from two climatically different regions of the Romanian Carpathians, to complement paleoenvironmental data previously reported. Oribatid mites and ostracods are the most common invertebrates in the studied cave sediments. Some of the identified taxa are new to science, and most of them are indicative for either warm and/or cold stages or dry and/or wetter oscillations. In two caves the fossil invertebrates records indicate rapid climate oscillations during times known for a relatively stable climate. By corroborating the fossil invertebrates' record with the information given by magnetic properties and sediment structures, complementary data on past vegetation, temperatures and hydraulic regimes could be gathered. This paper analyzes the potential of fossil invertebrate records as a paleoenvironmental proxy, potential problems and pitfalls.

  5. Molecular Characterization of Aquatic Bacterial Communities in Dinaric Range Caves.

    PubMed

    Pleše, Bruna; Pojskić, Naris; Ozimec, Roman; Mazija, Mirna; Ćetković, Helena; Lukić-Bilela, Lada

    2016-07-01

    Dinaric limestone cave systems, recognized as a hotspot of subterranean biodiversity, inhabit composite microbial communities whose structure, function and importance to ecosystems was poorly considered until the last few years. Filamentous microbial biofilms from three caves in Dinaric karst were assessed using 16S rRNA-based phylogenetic approach combined with universally protein coding genes/proteins. Studied clone libraries shared divisions but phylogenetic distribution of the obtained phylotypes differed: in Veternica and Vjetrenica clone libraries, Nitrospirae prevailed with 36% and 60% respectively, while in Izvor Bistrac the most abundant were Alphaproteobacteria (41%) followed by Firmicutes (32%). Moreover, three phylotypes were associated with novel uncultured candidate divisions OP3, WS5 and OD1 revealing the diversity and uniqueness of the microbial world in caves. Deeply understanding subterranean habitats could elucidate many new aspects in phylogeny and evolution of microorganisms as well as animal taxa, adjacent to their energy suppliers in microbial communities and biofilms. PMID:27329058

  6. Late Pleistocene human remains from Wezmeh Cave, western Iran.

    PubMed

    Trinkaus, Erik; Biglari, Fereidoun; Mashkour, Marjan; Monchot, Hervé; Reyss, Jean-Louis; Rougier, Hélène; Heydari, Saman; Abdi, Kamyar

    2008-04-01

    Paleontological analysis of remains from Wezmeh Cave in western Iran have yielded a Holocene Chalcolithic archeological assemblage, a rich Late Pleistocene carnivore faunal assemblage, and an isolated unerupted human maxillary premolar (P(3) or possibly P(4)). Species representation and U-series dating of faunal teeth place the carnivore assemblage during oxygen isotope stages (OIS) 3 and 2, and noninvasive gamma spectrometry dating of the human premolar places it at least as old as early OIS 2. The human premolar crown morphology is not diagnostic of late archaic versus early modern human affinities, but its buccolingual diameter places it at the upper limits of Late Pleistocene human P(3) and P(4) dimensions and separate from a terminal Pleistocene regional sample. Wezmeh Cave therefore provides additional Paleolithic human remains from the Zagros Mountains and further documents Late Pleistocene human association with otherwise carnivore-dominated cave assemblages. PMID:18000894

  7. Medical illustration: from caves to cyberspace.

    PubMed

    Tsafrir, J; Ohry, A

    2001-06-01

    The human body has been depicted in ancient cave-paintings, in primitively sculpted figures, and through all the ages in various forms of artistic expression. The earliest medical texts were descriptive but not illustrated. Later, as it became clear that knowledge of the human body and all its systems was essential to the practice of healing, texts were accompanied by illustrations which became an integral part of the teaching process. The illustrators included artists, whose interest was primarily artistic, but who were sometimes employed by surgeons or physicians to illustrate their texts. Occasionally, the physicians or scientists accompanied their texts with their own illustrations, and in the last century, medical illustration, in its infinite variety of techniques, has been developed as a profession in its own right. As knowledge was extended, permitted by social and cultural change, as well as by technological advances, the types of illustrations have ranged from gross anatomy through dissections showing the various organ systems, histological preparations, and radiological images, right up to the computerized digital imagery that is available today, which allows both static and dynamic two- and three-dimensional representations to be transmitted electronically across the world in a matter of seconds. The techniques used to represent medical knowledge pictorially have been as varied as the illustrators themselves, involving drawing, engraving, printing, photography, cinematography and digital processing. Each new technique has built on previous experience to broaden medical knowledge and make it accessible to an ever-widening audience. This vast accumulation of pictorial material has posed considerable problems of storage, cataloguing, retrieval, display and dissemination of the information, as well as questions of ethics, validity, manipulation and reliability. This paper traces these developments, illustrating them with representative examples drawn from

  8. Mapping of a complex lava flow field using regular surveys with a portable thermal camera

    NASA Astrophysics Data System (ADS)

    Calvari, S.; Lodato, L.; Garfi, G.; Spampinato, L.; Andronico, D.

    2003-04-01

    The use of a portable thermal camera has been applied to routine monitoring of the 2002 Etna flank eruption. The eruption started on 27 October with the opening of a field of fissures on the north and south flanks of the volcano. Abundant ash emission from the whole length of the 10 km long fissure covered the lava flow field, making it impossible to approach the active lava even with helicopters. Additionally, the northern lava flows were spreading into a forest, causing fire and impeding routine measures in field and lava flow mapping from the ground. This situation continued for several days. The only way to obtain an approximate mapping of the flow field was to use a thermal camera from helicopter, obtaining inclined images of the lava flow field. This allowed: (1) an estimation of the speed of the spreading lava and (2) of the position of the lava flow fronts, (3) evaluation of effusion rate, (4) daily covered area, and (5) organisation of evacuation plans for people living close to the area affected by flows. All these information were essential for civil protection purposes. Emission of lava flows from the north fissure stopped on 5 November 2002. During the following phase of the eruption, when lava flows spread for over two months only on the southern flank of the volcano, little ash emission from the craters allowed us a better view of the lava flow field. However, since the active flows were spreading on a limited surface, flanking and overlapping each other several times, distinction between active and inactive lava flows was made possible only by using a thermal camera. This device allowed us to distinguish active lava flows, inflating flow fronts, lava tubes and ephemeral vents, giving us a comprehensive view of the evolution of the lava flow field. It also helped us discover new vent opening from the base of the cinder cone, in a way to advice the Civil Protection authorities about the future path of new lava flows.

  9. Geochemistry and mineralogy of the phonolite lava lake, Erebus volcano, Antarctica: 1972 2004 and comparison with older lavas

    NASA Astrophysics Data System (ADS)

    Kelly, Peter J.; Kyle, Philip R.; Dunbar, Nelia W.; Sims, Kenneth W. W.

    2008-11-01

    Mount Erebus, Antarctica, is a large (3794 m) alkaline open-conduit stratovolcano that hosts a vigorously convecting and persistently degassing lake of anorthoclase phonolite magma. The composition of the lake was investigated by analyzing glass and mineral compositions in lava bombs erupted between 1972 and 2004. Matrix glass, titanomagnetite, olivine, clinopyroxene, and fluor-apatite compositions are invariant and show that the magmatic temperature (˜ 1000°C) and oxygen fugacity (ΔlogFMQ = - 0.9) have been stable. Large temperature variations at the lake surface (~ 400-500°C) are not reflected in mineral compositions. Anorthoclase phenocrysts up to 10 cm in length feature a restricted compositional range (An 10.3-22.9Ab 62.8-68.1Or 11.4-27.2) with complex textural and compositional zoning. Anorthoclase textures and compositions indicate crystallization occurs at low degrees of effective undercooling. We propose shallow water exsolution causes crystallization and shallow convection cycles the anorthoclase crystals through many episodes of growth resulting in their exceptional size. Minor variations in eruptive activity from 1972 to 2004 are decoupled from magma compositions. The variations probably relate to changes in conduit geometry within the volcano and/or variable input of CO 2-rich volatiles into the upper-level magma chamber from deeper in the system. Eleven bulk samples of phonolite lava from the summit plateau that range in age from 0 ± 4 ka to 17 ± 8 ka were analyzed for major and trace elements. Small compositional variations are controlled by anorthoclase content. The lavas are indistinguishable from modern bulk lava bomb compositions and demonstrate that Erebus volcano has been erupting lava and tephra from the summit region with the same bulk composition for ˜ 17 ka.

  10. Vermiculation patterns in Coiba Mare cave, Bihor Mountains, Romania

    NASA Astrophysics Data System (ADS)

    Bojar, Ana-Voica; Guja, Ovidiu; Stefanescu, Daniel

    2014-05-01

    Vermiculation patterns developing on cave surfaces are certainly a spectacular feature. Sometimes vermiculation cover hundreds of square meters, like for example in Coiba Mare cave, which is situated in the Bihor Mountains, Romania. The Coiba Mare Cave is located at 1020 m altitude, on the Gardisoara Valley, not far from the Casa de Piatra Hamlet, in the Apuseni Natural Park (Bihor Mountains) situated in the western part of Romania. The first written document concerning the cave dates back to 1929, when R. Jeannel and E. Racovitza presented a brief description. Speleological investigations, which were started by I. Viehmann, D. Coman and M. Bleahu in 1953, were continued by several speleological clubs during 1975-1976. In this study, we are investigating the mineralogy, stable isotope distribution and patterns of vermiculations in the Coiba Mare cave. Material from the vermiculations developed on cave wall was analysed using Powder X-ray diffraction (PXRD), Fourier transformed infrared (FTIR) and energy dispersive analyses (EDS). The material consists mainly of calcite with traces of quartz, muscovite, chlinochlore, kaolinite, potassium feldspar and organic material. In Coiba Mare, the general look of the vermiculation pattern is that of a "pelli de leopardo" (Leopard's spots), a term used by Bini et al. (1978) for large vermiculations composed of clay. In the light of previous literature and according, to the own field and laboratory data a mechanism responsible for the formation of vermiculations is proposed. Evaporation and water film rupture cause the concentration of the loose particles. Evaporation is also associated with the formation of calcite microcrystals at the water-air interface. Concentration of the particle in vermiculations patterns and crystallisation is the result of evaporation and shrinking water spots.

  11. Secondary sulfate minerals from Alum Cave Bluff: Microscopy and microanalysis

    SciTech Connect

    Lauf, R.J.

    1997-07-01

    Microcrystals of secondary sulfate minerals from Alum Cave Bluff, Great Smoky Mountains National Park, were examined by scanning electron microscopy and identified by X-ray fluorescence (XRF) in the SEM. Among the samples the author discovered three new rare-earth sulfates: coskrenite-(Ce), levinsonite-(Y), and zugshunstite-(Ce). Other minerals illustrated in this report include sulfur, tschermigite, gypsum, epsomite, melanterite, halotrichite, apjohnite, jarosite, slavikite, magnesiocopiapite, and diadochite. Additional specimens whose identification is more tentative include pickeringite, aluminite, basaluminite, and botryogen. Alum Cave is a ``Dana locality`` for apjohnite and potash alum, and is the first documented North American occurrence of slavikite.

  12. Highly siderophile element constraints on the genesis of Azorean lavas

    NASA Astrophysics Data System (ADS)

    Waters, C. L.; Watanabe, S.; Olson, K. M.; Walker, R. J.; Widom, E.; Hanan, B. B.; Day, J. M.

    2013-12-01

    Ocean island basalts (OIB) from the Azores archipelago show incompatible element and Sr-Nd-Hf-Pb isotopic heterogeneity both among different islands and within individual islands. This heterogeneity has commonly been attributed to the presence of a mantle plume delivering diverse recycled materials--including terrigenous sediments, metasomatized subcontinental lithosphere, and oceanic crust--to the melting region beneath the Azores (Turner et al., 1997; Widom and Shirey, 1996; Beier et al., 2007). Despite an abundance of datasets including major and trace element and Sr, Nd, Hf, and Pb isotopic compositions, the origin of elemental and isotopic heterogeneity in the Azores remains vigorously debated. We report new highly siderophile element (HSE: Os, Ir, Pd, Pt, Ru, Re) abundance data alongside major and trace element abundance and Nd-Hf-Os-Pb isotope data for a suite of high MgO (8-17 wt%) lavas from the islands of Sao Miguel, Pico, Faial, and Terceira. These lavas span most of the range of incompatible trace element and Nd-Hf-Pb isotopic heterogeneity observed for the Azores. Because HSEs are largely controlled by sulfide, they provide an alternative to the classic perspective of OIB petrogenesis derived from lithophile elements. The results show distinct fractionation patterns for HSEs from different islands at a similar range of MgO contents. Lavas from Pico and Faial have lower absolute HSE abundances (total HSE abundances ~0.001 × CI chondrite; Ir=0.014-0.133 ppb) and are generally more homogeneous than lavas from Terceira and Sao Miguel (total HSE = ~0.003 × CI chondrite; Ir=0.038-0.657 ppb)). Faial and Pico lavas (IrN* = 0.8×0.3, where IrN* = IrN/[(OsN+RuN)0.5] x 100) also commonly lack the positive relative enrichment in Ir observed in Terceira and Sao Miguel lavas (IrN* = 2.4 ×1.1). In contrast to previous studies of OIB in which HSEs are observed to positively correlate with MgO (e.g., Day, 2013), only Re correlates with MgO, as expected given its

  13. Constraints on Lava Flow Emplacement Derived From Precision Topographic Measurements

    NASA Astrophysics Data System (ADS)

    Zimbelman, J. R.; Bjonnes, E. E.

    2005-12-01

    Precision topography obtained with a Differential Global Positioning System (DGPS) was used to derive constraints on the physical properties of two lava flows on the Big Island of Hawaii. We used a Trimble 4800 DGPS to collect positional information across the lava flows with < 2 cm horizontal and < 4 cm vertical precision (but field tests show that points are usually repeatable to < 1 cm both horizontally and vertically). The DGPS data were overlaid on georeferenced aerial and satellite imaging data, allowing us to correlate the measured topographic points to field notes and photographs, as well as to the local setting evident in the vertical images. We combined field and imaging data for the eastern lobe of the 1907 basalt flow from the southwestern rift zone of Mauna Loa volcano, east of the Ocean View Estates subdivision, and for portions of a grass-covered Pleistocene benmoreite flow near Mana on the western flank of Mauna Kea volcano. Measured physical dimensions of the Hawaiian lava flows obtained from the DGPS data were then used to calculate the yield strength, average effusion rate, and effective viscosity of the lavas using published relationships derived from diverse theories of fluid flow. Yield strengths obtained from three different expressions ranged from 5800 to 56000 Pa for the Mauna Loa basalt flow and from 13000 to 28000 Pa for the Mauna Kea benmoreite flow. Total flow length could not be determined for the Mauna Kea flow, but the entire surface portion of the 1907 flow is well exposed; this allowed us to calculate an average effusion rate of 29 m/s and effective viscosities ranging from 17000 to 280000 Pa-s for this flow, broadly consistent with values published for the 1984 basalt flow from the eastern rift zone of Mauna Loa. These results improve our confidence in being able to derive similar constraints on the likely emplacement conditions of lava flows on other planets, such as the enormous lava flows commonly found on the martian, venusian

  14. Paleomagnetism of some Precambrian basaltic flows and red beds, Eastern Grand Canyon, Arizona

    USGS Publications Warehouse

    Elston, D.P.; Robert, Scott G.

    1973-01-01

    Lava flows and red sandstone beds near the middle of the Upper Precambrian Grand Canyon Series exhibit stable remanent magnetization. The beds are about 1000 m stratigraphically above rocks of the Grand Canyon Series for which paleomagnetic poles have been reported. All specimens were subjected to stepwise thermal (200??-700??C) or alternating field (25-5000 Oe) demagnetization for the determination of characteristic magnetization. The pole for two flows and an intercalated sandstone bed of the Cardenas Lavas of Ford, Breed and Mitchell (upper Unkar Group), is at 174.6W, 0.4N (N = 10, K = 50, ??95 = 6.9??). The pole for a weathered zone developed across the Cardenas Lavas is at 167.8W, 49.4N (N = 5, K = 79, ??95 = 8.6??). The pole for directly overlying sandstone of the Nankoweap Formation of Maxson is at 174.4E, 12.5N (N = 6, K = 105, ??95 = 6.6??). These poles lie on or near, and appear to follow, part of an apparent polar wandering path recently proposed for the Precambrian of North America by Spall. If the fit is not accidental, little or no rotation has occurred between north-central Arizona and parts of the North American continent used to define the proposed path. ?? 1973.

  15. The sources and sinks of CO2 in caves under mixed woodland and grassland vegetation

    NASA Astrophysics Data System (ADS)

    Breecker, Daniel O.; Payne, Ashley E.; Quade, Jay; Banner, Jay L.; Ball, Carolyn E.; Meyer, Kyle W.; Cowan, Brian D.

    2012-11-01

    We measured concentrations and stable carbon isotope compositions of carbon dioxide in the atmospheres of three caves in central Texas and one cave in southern Arizona in order to identify CO2 sources and sinks. The vegetation above the caves studied is either savannah (two caves, above which vegetation has been minimally disturbed) or discrete patches of grassland and woodland (two caves, above which vegetation has been highly disturbed). We tested two hypotheses concerning CO2 in the cave atmospheres: (1) cave ventilation by tropospheric air is the primary sink for CO2 and (2) CO2 is primarily derived from the deepest rooting plants growing above the caves. Within caves, we monitored CO2 at individual locations on monthly and daily time-scales and measured CO2 along transects with increasing distance from the cave entrances. We also measured CO2 in the pore spaces of soils under grasses and trees above each of the caves. We calculated δ13C values of respired CO2 (δ13Cr) for all gas samples using measured δ13C values and CO2 concentrations. We then identified the sources of cave CO2 by comparing cave-air and soil CO2δ13Cr values. At all locations in each Texas cave, CO2 concentrations were highest (lowest) and δ13C values were lowest (highest) during the summer (winter). Cave-air CO2 concentrations consistently increased and δ13C values consistently decreased with distance from the cave entrances. Similar but smaller magnitude seasonal variations in CO2 concentrations occurred in the Arizona cave and no seasonal or spatial variation in the δ13C of cave-air CO2 was observed. The mean δ13Cr values of CO2 in soils under grass were 3.5-4.5‰ higher than the δ13Cr values of CO2 in soils under trees. In the caves under savannah, mean δ13Cr values of cave-air CO2 (-24‰ in both caves) were within 1‰ of the mean δ13Cr values of CO2 in soils under trees. In caves covered by large, contiguous areas of grassland, the δ13Cr values of cave-air CO2 were similar

  16. Seasonal variations of 14C and δ13C for cave drip waters in Ryugashi Cave, Shizuoka Prefecture, central Japan

    NASA Astrophysics Data System (ADS)

    Minami, Masayo; Kato, Tomomi; Horikawa, Keiji; Nakamura, Toshio

    2015-11-01

    Speleothem 14C has recently emerged as a potentially powerful proxy for hydrology changes in comparison with atmospheric 14C calibration curve, rather than as a direct dating tool, apart from a time marker using bomb peak of 14C. Some possible causes for the relationship between speleothem 14C content (or dead carbon fraction: DCF) and karst hydrology have been proposed, such as changes in temperature, precipitation, drip water flow dynamics, cave air ventilation, soil air pCO2. In this study, we investigated seasonal variation in 14C and δ13C of drip water in Ryugashi Cave, Shizuoka Prefecture, central Japan, to examine the causes of the 14C and δ13C variations in a speleothem. The results show that different 14C concentrations and δ13C values of drip water from the Ryugashi Cave, were exhibited at different sites of the Caves No. 1, No. 3, and No. 4, which have different temperature, air pCO2, and flow paths. Further, the 14C and δ13C of drip waters showed seasonal variations at all sites, which were lower in fall and winter, and higher in spring and summer, though the extent of the variations was different among the sites. The 14C in drip waters tended to be correlated with the drip rates: 14C tended to be higher in drip waters with higher drip rates, and also correlated with rainfall amount around the Ryugashi Cave, especially for the drip waters in Cave No. 3, which are considered to have simpler flow paths. The increase in rainfall amount could bring the increase in drip rate of drip water, and then the decrease in interaction between solution and karst, resulting in 14C increase (DCF decrease) in drip water. Accordingly, the reconstruction of precipitation could be performed using 14C variation in a speleothem formed by drip water with simple flow dynamics.

  17. Detrital cave sediments as recorders of environmental changes, the Seso Cave System (Huesca, Spain)

    NASA Astrophysics Data System (ADS)

    Oliva-Urcia, Belén; Bartolomé, Miguel; Moreno, Ana; Gil-Romera, Graciela; Sancho, Carlos; Muñoz, Arsenio; Osácar, Cinta

    2014-05-01

    The sedimentological study of a waterlaid detrital sequence of ~ 240 cm thick within the Seso Cave System (West-Central Pyrenees) reveals two types of sedimentary environments, the lower part (first 100 cm) is made of autochthonous (piping detached material from the Eocene marls host rock inside of the cavity) and the upper part, which is mixed with the pond deposits from 100 to 190 cm, is made of allochthonous (stream transported sediments from the outside) sediments. In these sediments, seven charcoal samples were dated using 14C AMS ranging from 2080 to 650 cal yr BP (130 BC-1300 AD). Two levels of human occupation of the cave have been recognized by ceramics associated to the Iberian Period and to the Roman Period, respectively. The autochthonous material is made up of fine grain laminated sediments (lutites and marls) and corresponds to pond facies, whereas the allochthonous material is lutites and sands and corresponds to stream facies. The increase in sedimentation rate towards the end of the sequence points to an intensification of the alluvial activity as a possible consequence of a more arid climate during the Medieval Climate Anomaly. In addition to the sedimentological and chronological studies, magnetic analyses were performed in 44 standard samples taken along the profile. The magnetic signature of the samples confirm the difference in the provenance of the studied sequence, with lower values in the natural remanent magnetization and magnetic susceptibility in the pond facies than in the stream facies due to the lower quantity of ferromagnetic minerals in the former. The rock magnetic analyses reveal that the ferromagnetic mineral is a soft coercive mineral with Curie temperatures of 580ºC, i.e., magnetite. In addition, the direction of the paleomagnetic record of the sediments is modified by the two human settlements.

  18. Fluidized bed calciner apparatus

    DOEpatents

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  19. Volunteer Shelter Bed Programs.

    ERIC Educational Resources Information Center

    Little (Arthur D.), Inc., Washington, DC.

    The volunteer shelter bed program development guidelines in this booklet are offered as a community-based alternative to the institutionalization of status offenders. The volunteer shelter bed program is described as a nonsecure residential alternative for status offenders, which can be implemented without the creation of new facilities or the…

  20. Lava-seawater vapor interaction at the mid-ocean ridge crest: an important volcanic process to explain lava transport and flow morphology on the deep sea floor

    NASA Astrophysics Data System (ADS)

    Ridley, W. I.; Perfit, M.; Fornari, D.; Cann, J.; Smith, D.

    2003-12-01

    Eruption of lava from seafloor vents at the mid-ocean ridge (MOR) crest remains a poorly understood phenomena, despite the fact that it is the dominant volcanic process on earth. During the last decade only a handful of MOR eruptions have been documented using either NOAA-PMEL hydrophone detected events or serendipity, and observations of seafloor manifestations of those effusive events did not capture the actual interaction between erupted lava and near-freezing ambient seawater. Because of the great physical and technological obstacles to actually observing volcanic eruption processes in the deep sea, we must rely on the physical and chemical evidence left behind in the cooled seafloor lava flows to deduce the likely processes that occurred. Based on observations and sampling of numerous lava flows from slow to fast-spreading MORs we find a plethora of delicate macroscopic features preserved on the crusts of lava flows and in lava pillars that suggest intense and extensive interactions between hot magma and seawater during seafloor eruptions resulting in a briny vapor phase. Undersides of many lobate and sheet lava crusts have glassy drips (lava stalactites) and flanges (relict bubble walls) that could only have formed in cavities initially filled with a hot vapor at magmatic temperatures as lava was transported across the seafloor. Detailed petrologic observations of the surfaces of drips and flanges, including the presence of molten salt, exotic Cl- and S-bearing secondary silicates, secondary sulfates and almost pure forsterite, suggest that the vapor phase was flashed seawater. This vapor phase is a key to understanding delicate drip structures formed on lava crusts and the mechanisms by which lava is distributed far from eruptive fissures on the deep sea floor. We suggest that vaporized seawater is incorporated at the flow front as lava moves over the seafloor. The vapor rises as streams of bubbles through the lava behind the flow front and then collects

  1. Subglacial lava propagation, ice melting and heat transfer during emplacement of an intermediate lava flow in the 2010 Eyjafjallajökull eruption

    NASA Astrophysics Data System (ADS)

    Oddsson, Björn; Gudmundsson, Magnús T.; Edwards, Benjamin R.; Thordarson, Thorvaldur; Magnússon, Eyjólfur; Sigurðsson, Gunnar

    2016-07-01

    During the 2010 Eyjafjallajökull eruption in South Iceland, a 3.2-km-long benmoreite lava flow was emplaced subglacially during a 17-day effusive-explosive phase from April 18 to May 4. The lava flowed to the north out of the ice-filled summit caldera down the outlet glacier Gígjökull. The flow has a vertical drop of about 700 m, an area of ca. 0.55 km2, the total lava volume is ca. 2.5·107 m3 and it is estimated to have melted 10-13·107 m3 of ice. During the first 8 days, the lava advanced slowly (<100 m day-1), building up to a thickness of 80-100 m under ice that was initially 150-200 m thick. Faster advance (up to 500 m day-1) formed a thinner (10-20 m) lava flow on the slopes outside the caldera where the ice was 60-100 m thick. This subglacial lava flow was emplaced along meltwater tunnels under ice for the entire 3.2 km of the flow field length and constitutes 90 % of the total lava volume. The remaining 10 % belong to subaerial lava that was emplaced on top of the subglacial lava flow in an ice-free environment at the end of effusive activity, forming a 2.7 km long a'a lava field. About 45 % of the thermal energy of the subglacial lava was used for ice melting; 4 % was lost with hot water; about 1 % was released to the atmosphere as steam. Heat was mostly released by forced convection of fast-flowing meltwater with heat fluxes of 125-310 kWm-2.

  2. Microscopic and macroscopic assessment of the emplacement of obsidian lavas

    NASA Astrophysics Data System (ADS)

    Befus, K. S.; Williams, M.; Gardner, J. E.

    2013-12-01

    Rhyolitic obsidian lavas are common in silicic volcanic systems, but quantitative data related to the emplacement of such lavas is rare. To assess the emplacement dynamics of rhyolitic obsidian lavas we measured the 3D orientation of microlites in samples collected systematically across five of the Central Plateau Member lavas of Yellowstone. Eruption volumes and maximum flow distances of targeted lava flows range from 0.01-70 km3 and 0.13-22 km, respectively. The dataset allows us to examine how deformation during emplacement varies with eruption size. Oriented thin sections were prepared from samples thought to be in place (i.e., not rotated by autobrecciation or erosion). In each sample, we petrographically measured the trend and plunge of >130 acicular Fe-Ti oxide microlites. The 3D microlite orientation can be used in two ways to understand the kinematics of emplacement. First, microlite orientations can be used to infer the dominant directions of fluid stretching because microlite long axes align in the direction of local extension. Second, the degree of alignment of a microlite population (i.e., standard deviation of trend and plunge), irrespective of preferred orientation, is dependent on the strain microlites experience during emplacement. We found that microlites are strongly aligned in all samples from all flows. Microlites are aligned roughly parallel to the direction of flow in samples collected near the flow front. Conversely, microlites are generally aligned orthogonal to the flow direction in samples collected from interior portions of the flows. In individual flows, the degree of alignment shows no correlation with distance travelled, instead it has slight random variations. Large- and small-volume flows display indistinguishable degrees of microlite alignment. Microlites provide a indicator of flow direction near flow fronts where strain is imparted by simple shear. In the interior portions of flows, strain is induced by pure shear via flattening

  3. Estimates of Lava Eruption Rates at Alba Patera, Mars

    NASA Technical Reports Server (NTRS)

    Baloga, S. M.; Pieri, D. C.

    1985-01-01

    The Martian volcanic complex Alba Patera exhibits a suite of well-defined, long and relatively narrow lava flows qualitatively resembling those found in Hawaii. Even without any information on the duration of the Martian flows, eruption rates (total volume discharge/duration of the extrusion) estimates are implied by the physical dimensions of the flows and the likely conjecture that Stephan-Boltzmann radiation is the dominating thermal loss mechanism. The ten flows in this analysis emanate radially from the central vent and were recently measured in length, plan areas, and average thicknesses by shadow measurement techniques. The dimensions of interest are shown. Although perhaps morphologically congruent to certain Hawaiian flows, the dramatically expanded physical dimensions of the Martian flows argues for some markedly distinct differences in lava flow composition for eruption characteristics.

  4. Profiling bacterial diversity in a limestone cave of the western Loess Plateau of China

    PubMed Central

    Wu, Yucheng; Tan, Liangcheng; Liu, Wuxing; Wang, Baozhan; Wang, Jianjun; Cai, Yanjun; Lin, Xiangui

    2015-01-01

    Bacteria and archaea sustain subsurface cave ecosystems by dominating primary production and fueling biogeochemical cyclings, despite the permanent darkness and shortage of nutrients. However, the heterogeneity and underlying mechanism of microbial diversity in caves, in particular those well connect to surface environment are largely unexplored. In this study, we examined the bacterial abundance and composition in Jinjia Cave, a small and shallow limestone cave located on the western Loess Plateau of China, by enumerating and pyrosequencing small subunit rRNA genes. The results clearly reveal the contrasting bacterial community compositions in relation to cave habitat types, i.e., rock wall deposit, aquatic sediment, and sinkhole soil, which are differentially connected to the surface environment. The deposits on the cave walls were dominated by putative cave-specific bacterial lineages within the γ-Proteobacteria or Actinobacteria that are routinely found on cave rocks around the world. In addition, sequence identity with known functional groups suggests enrichments of chemolithotrophic bacteria potentially involved in autotrophic C fixation and inorganic N transformation on rock surfaces. By contrast, bacterial communities in aquatic sediments were more closely related to those in the overlying soils. This is consistent with the similarity in elemental composition between the cave sediment and the overlying soil, implicating the influence of mineral chemistry on cave microhabitat and bacterial composition. These findings provide compelling molecular evidence of the bacterial community heterogeneity in an East Asian cave, which might be controlled by both subsurface and surface environments. PMID:25870592

  5. Profiling bacterial diversity in a limestone cave of the western Loess Plateau of China.

    PubMed

    Wu, Yucheng; Tan, Liangcheng; Liu, Wuxing; Wang, Baozhan; Wang, Jianjun; Cai, Yanjun; Lin, Xiangui

    2015-01-01

    Bacteria and archaea sustain subsurface cave ecosystems by dominating primary production and fueling biogeochemical cyclings, despite the permanent darkness and shortage of nutrients. However, the heterogeneity and underlying mechanism of microbial diversity in caves, in particular those well connect to surface environment are largely unexplored. In this study, we examined the bacterial abundance and composition in Jinjia Cave, a small and shallow limestone cave located on the western Loess Plateau of China, by enumerating and pyrosequencing small subunit rRNA genes. The results clearly reveal the contrasting bacterial community compositions in relation to cave habitat types, i.e., rock wall deposit, aquatic sediment, and sinkhole soil, which are differentially connected to the surface environment. The deposits on the cave walls were dominated by putative cave-specific bacterial lineages within the γ-Proteobacteria or Actinobacteria that are routinely found on cave rocks around the world. In addition, sequence identity with known functional groups suggests enrichments of chemolithotrophic bacteria potentially involved in autotrophic C fixation and inorganic N transformation on rock surfaces. By contrast, bacterial communities in aquatic sediments were more closely related to those in the overlying soils. This is consistent with the similarity in elemental composition between the cave sediment and the overlying soil, implicating the influence of mineral chemistry on cave microhabitat and bacterial composition. These findings provide compelling molecular evidence of the bacterial community heterogeneity in an East Asian cave, which might be controlled by both subsurface and surface environments. PMID:25870592

  6. Effects of lava-dome growth on the crater glacier of Mount St. Helens, Washington: Chapter 13 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    Walder, Joseph S.; Schilling, Steve P.; Vallance, James W.; LaHusen, Richard G.

    2008-01-01

    The process of lava-dome emplacement through a glacier was observed for the first time as the 2004-6 eruption of Mount St. Helens proceeded. The glacier that had grown in the crater since the cataclysmic 1980 eruption was split in two by the new lava dome. The two parts of the glacier were successively squeezed against the crater wall. Photography, photogrammetry, and geodetic measurements document glacier deformation of an extreme variety, with strain rates of extraordinary magnitude as compared to normal temperate alpine glaciers. Unlike such glaciers, the Mount St. Helens crater glacier shows no evidence of either speed-up at the beginning of the ablation season or diurnal speed fluctuations during the ablation season. Thus there is evidently no slip of the glacier over its bed. The most reasonable explanation for this anomaly is that meltwater penetrating the glacier is captured by a thick layer of coarse rubble at the bed and then enters the volcano’s groundwater system rather than flowing through a drainage network along the bed. Mechanical consideration of the glacier-squeeze process also leads to an estimate for the driving pressure applied by the growing lava dome.

  7. Spotted hyena and steppe lion predation behaviours on cave bears of Europe - ?Late Quaternary cave bear extinction as result of predator stress

    NASA Astrophysics Data System (ADS)

    Diedrich, Cajus G.

    2010-05-01

    Cave bears hibernated in caves all over Eurasia (e.g. Rabeder et al., 2000) including alpine regions using mainly larger caves for this purpose. Late Quaternary spotted hyenas Crocuta crocuta spelaea instead occupied mainly areas close to the cave entrances as their dens (Diedrich and Žák 2006, Diedrich 2010). The largest predator, the steppe lion Panthera leo spelaea was only a sporadic cave dweller (Diedrich 2007b, 2009b). His presence and its remains from caves all over Europe can be recently explained best as result of imported carcasses after killing by their largest antagonists, the Late Quaternary spotted hyenas. In some cases the kill might have happened in the hyena den cave itself during the theft of prey remains by lions (Diedrich 2009a). Another reason of their remains in caves of Europe is the hunting onto the herbivorous cave bears, especially during hibernation times, when megafauna prey was less available in the open environments (Diedrich 2009c). These lion remains from caves of Europe, nearly all of which were from adult animals, provide evidence of active predation by lions onto cave bears even in medium high alpine regions (Diedrich 2009b, in review). Lion skeletons in European cave bear dens were therefore often found amongst originally articulated cave bear skeletons or scattered cave bear remains and even close to their hibernation nests (Diedrich et al. 2009c, in review). Not only lions fed on cave bears documented mainly by the large quantities of chewed, punctured and crushed cave bear long-bones; even damaged skulls reveal that hyenas scavenged primarily on cave bear carcasses which were mainly responsible for the destruction of their carcasses and bones (Diedrich 2005, 2009d). Predation and scavenging on cave bears by the two largest Late Quaternary predators C. c. spelaea and P. l. spelaea explains well the large quantity of fragmented cave bear bones over all European caves in low to medium high mountainous elevations, whereas in

  8. Sulfate-reducing bacteria are common members of bacterial communities in Altamira Cave (Spain).

    PubMed

    Portillo, M Carmen; Gonzalez, Juan M

    2009-01-15

    The conservation of paleolithic paintings such as those in Altamira Cave (Spain) is a primary objective. Recent molecular studies have shown the existence of unknown microbial communities in this cave including anaerobic microorganisms on cave walls. Herein, we analyzed an anaerobic microbial group, the sulfate-reducing bacteria (SRB), from Altamira Cave with potential negative effects on painting conservation. In the present work, the communities of bacteria and SRB were studied through PCR-DGGE analysis. Data suggest that SRB communities represent a significant, highly diverse bacterial group in Altamira Cave. These findings represent a first report on this physiological group on caves with paleolithic paintings and their potential biodegradation consequences. Expanding our knowledge on microbial communities in Altamira Cave is a priority to design appropriate conservation strategies. PMID:19027143

  9. Topographic and Stochastic Influences on Pahoehoe Lava Lobe Emplacement

    NASA Technical Reports Server (NTRS)

    Hamilton, Christopher W.; Glaze, Lori S.; James, Mike R.; Baloga, Stephen M.

    2013-01-01

    A detailed understanding of pahoehoe emplacement is necessary for developing accurate models of flow field development, assessing hazards, and interpreting the significance of lava morphology on Earth and other planetary surfaces. Active pahoehoe lobes on Kilauea Volcano, Hawaii, were examined on 21-26 February 2006 using oblique time-series stereo-photogrammetry and differential global positioning system (DGPS) measurements. During this time, the local discharge rate for peripheral lava lobes was generally constant at 0.0061 +/- 0.0019 m3/s, but the areal coverage rate of the lobes exhibited a periodic increase every 4.13 +/- 0.64 minutes. This periodicity is attributed to the time required for the pressure within the liquid lava core to exceed the cooling induced strength of its margins. The pahoehoe flow advanced through a series of down slope and cross-slope breakouts, which began as approximately 0.2 m-thick units (i.e., toes) that coalesced and inflated to become approximately meter-thick lobes. The lobes were thickest above the lowest points of the initial topography and above shallow to reverse facing slopes, defined relative to the local flow direction. The flow path was typically controlled by high-standing topography, with the zone directly adjacent to the final lobe margin having an average relief that was a few centimeters higher than the lava inundated region. This suggests that toe-scale topography can, at least temporarily, exert strong controls on pahoehoe flow paths by impeding the lateral spreading of the lobe. Observed cycles of enhanced areal spreading and inflated lobe morphology are also explored using a model that considers the statistical likelihood of sequential breakouts from active flow margins and the effects of topographic barriers.

  10. Fractal geometry of some Martian lava flow margins: Alba Patera

    NASA Technical Reports Server (NTRS)

    Kauhanen, K.

    1993-01-01

    Fractal dimension for a few lava flow margins on the gently sloping flanks of Alba Patera were measured using the structured walk method. Fractal behavior was observed at scales ranging from 20 to 100 pixels. The upper limit of the linear part of log(margin length) vs. log(scale) profile correlated well to the margin length. The lower limit depended on resolution and flow properties.

  11. Preferential Weathering of Carbonatite Lava at Ol Doinyo Lengai, Tanzania

    NASA Astrophysics Data System (ADS)

    Robertson, C. H.; Harpp, K. S.; Geist, D.; Bosselait, M.

    2014-12-01

    Although carbonatites have been produced since the Archean and are preserved in the geologic record, the East African Rift is home to the only active carbonatite volcano, at Ol Doinyo Lengai. It has long been known that the natrocarbonatites become strongly weathered the first time they are exposed to rain. We studied the weathering patterns in the field and have determined the mineralogical transformations via petrography and XRD. Mass transport is assessed by XRF and ICP-MS analyses. Water preferentially dissolves specific minerals in the pristine lava, permeating through earlier layers of flow to form stalactites, which have differing mineralogical composition. These hang both from the host flow and from the bottom of underlying earlier flows. The weathering product is characterized by trona, a hydrated carbonate mineral, as well as the sodium sulfate mineral aphthitalite. Data from XRD analysis of the carbonatite lava confirm transformation of its original minerals, nyerereite and gregoryite, into secondary hydrated carbonate minerals gaylussite and pirssonite (e.g., Zaitsev and Keller, 2006). This transformation is attributed to the instability of the erupted minerals at atmospheric conditions. Data from XRF analysis indicate a 4-fold increase in the amount of sodium present in the stalactite as well as a 8-fold increase in potassium. Trace element analysis by ICP-MS indicates significantly elevated levels of vanadium, copper, and rubidium in the weathering product, whereas strontium, barium, lanthanum, and cesium are left behind in high concentrations in the carbonatite lava. Our results provide further evidence supporting the proposal by Dawson et al. (1987) that calcium carbonate dominated lava flows result from extensive weathering of sodic carbonatite flows.

  12. Formation of Hrad Vallis (Mars) by low viscosity lava flows

    NASA Astrophysics Data System (ADS)

    Hopper, Joshua P.; Leverington, David W.

    2014-02-01

    Hrad Vallis is a Martian outflow channel previously interpreted as a product of aqueous outbursts from the subsurface, possibly involving mudflows associated with lahar-like events. However, an alternative volcanic hypothesis for the development of the system is worthy of consideration on the basis of (1) the nature of landforms preserved along component channels and adjacent uplands and (2) similarities between the basic properties of this system and large volcanic channels of the inner solar system. Hrad Vallis commences on the distal flanks of the Elysium Mons shield volcano, terminates within extensive volcanic plains, is associated with landforms typical of large volcanic channels, and shows evidence for having been a conduit for large volumes of lava. The properties of this system are consistent with incision by low viscosity lava. Crude thermal estimates suggest that this system could have formed through effusion of as little as ~ 10,900 km3 of magma to the surface, or ~ 6% of the volume of the terrestrial Columbia River Basalt Group. Incision rates of up to several meters per day are estimated for mechanical and thermal processes involving lava flows with depths of 5-20 m and dynamic viscosities of ~ 1 Pa s. Flow of lava within the Hrad Vallis system is predicted to have been fully turbulent and characterized by discharges as great as ~ 865,000 m3/s. Predicted flow conditions are consistent with those previously determined for Athabasca Valles, which also formed as a result of the expulsion of flows from structures associated with Elysium Mons.

  13. An analogue experimental model of depth fluctuations in lava lakes

    NASA Astrophysics Data System (ADS)

    Witham, Fred; Woods, Andrew W.; Gladstone, Charlotte

    2006-07-01

    Lava lakes, consisting of molten degassing lava in summit craters of active basaltic volcanoes, sometimes exhibit complex cycles of filling and emptying on time-scales of hours to weeks such as recorded at Pu’u’O’o in Hawaii and Oldoinyo Lengai in Tanzania. Here we report on a new series of analogue laboratory experiments of two-phase flow in a reservoir-conduit-lava lake system which spontaneously generates oscillations in the depth of liquid within the lake. During the recharge phase, gas supplied from a subsurface reservoir of degassing magma drives liquid magma up the conduit, causing the lake to fill. As the magmastatic pressure in the lake increases, the upward supply of magma, driven by the gas bubbles, falls. Eventually the upflow becomes unstable, and liquid drains downwards from the lake, driven by the magmastatic pressure of the overlying lake, suppressing the ascent of any more bubbles from the chamber. At a later stage, once the lake has drained sufficiently, the descent speed of liquid through the conduit decreases below the ascent speed of the bubbles, and the recharge cycle resumes. Application of a quantitative model of the experiments to the natural system is broadly consistent with field data.

  14. Calculated viscosity-distance dependence for some actively flowing lavas

    NASA Technical Reports Server (NTRS)

    Pieri, David

    1987-01-01

    The importance of viscosity as a gauge of the various energy and momentum dissipation regimes of lava flows has been realized for a long time. Nevertheless, despite its central role in lava dynamics and kinematics, it remains among the most difficult of flow physical properties to measure in situ during an eruption. Attempts at reconstructing the actual emplacement viscosities of lava flows from their solidified topographic form are difficult. Where data are available on the position of an advancing flow front as a function of time, it is possible to calculate the effective viscosity of the front as a function of distance from the vent, under the assumptions of a steady state regime. As an application and test of an equation given, relevant parameters from five recent flows on Mauna Loa and Kilauea were utilized to infer the dynamic structure of their aggregate flow front viscosity as they advanced, up to cessation. The observed form of the viscosity-distance relation for the five active Hawaiian flows examined appears to be exponential, with a rapid increase just before the flows stopped as one would expect.

  15. Map showing lava-flow hazard zones, Island of Hawaii

    USGS Publications Warehouse

    Wright, Thomas L.; Chun, Jon Y.F.; Exposo, Jean; Heliker, Christina; Hodge, Jon; Lockwood, John P.; Vogt, Susan M.

    1992-01-01

    This map shows lava-flow hazard zones for the five volcanoes on the Island of Hawaii. Volcano boundaries are shown as heavy, dark bands, reflecting the overlapping of lava flows from adjacent volcanoes along their common boundary. Hazard-zone boundaries are drawn as double lines because of the geologic uncertainty in their placement. Most boundaries are gradational, and the change In the degree of hazard can be found over a distance of a mile or more. The general principles used to place hazard-zone boundaries are discussed by Mullineaux and others (1987) and Heliker (1990). The differences between the boundaries presented here and in Heliker (1990) reflect new data used in the compilation of a geologic map for the Island of Hawaii (E.W. Wolfe and Jean Morris, unpub. data, 1989). The primary source of information for volcano boundaries and generalized ages of lava flows for all five volcanoes on the Island of Hawaii is the geologic map of Hawaii (E.W. Wolfe and Jean Morris, unpub. data, 1989). More detailed information is available for the three active volcanoes. For Hualalai, see Moore and others (1987) and Moore and Clague (1991); for Mauna Loa, see Lockwood and Lipman (1987); and for Kilauea, see Holcomb (1987) and Moore and Trusdell (1991).

  16. Palæomagnetism of Hawaiian lava flows

    USGS Publications Warehouse

    Doell, Richard R.; Cox, Allan

    1961-01-01

    PALÆOMAGNETIC investigations of volcanic rocks extruded in various parts of the world during the past several million years have generally revealed a younger sequence of lava flows magnetized nearly parallel to the field of a theoretical geocentric axial dipole, underlain by a sequence of older flows with exactly the opposite direction of remanent magnetization. A 180-degree reversal of the geomagnetic field, occurring near the middle of the Pleistocene epoch, has been inferred by many workers from such results1–3. This is a preliminary report of an investigation of 755 oriented samples collected from 152 lava flows on the island of Hawaii, selected to represent as many stratigraphic horizons as possible. (Sampling details are indicated in Table 1.) This work was undertaken because Hawaii's numerous thick sequences of lava flows, previously mapped as Pliocene to Historic by Stearns and Macdonald4, and afterwards assigned ages ranging from later Tertiary to Recent, by Macdonald and Davis5, appeared to offer an ideal opportunity to examine the most recent reversal of Earth's field.

  17. The formation of vesicular cylinders in pahoehoe lava flows

    NASA Astrophysics Data System (ADS)

    Fowler, A. C.; Rust, Alison C.; Vynnycky, M.

    2015-01-01

    Vertical cylinders of bubble-enriched, chemically evolved volcanic rock are found in many inflated pahoehoe lava flows. We provide a putative theoretical explanation for their formation, based on a description of a crystallising three-phase (liquid, solid, gas) crystal pile in which the water-saturated silicate melt exsolves steam and becomes more silica-rich as it crystallises anhydrous minerals. These cylinders resemble pipes that form in solidifying binary alloys as a result of sufficiently vigorous porous medium convection within the mush. A convection model with the addition of gas bubbles that provide the buoyancy source indicates that the effective Rayleigh number is too low for convection to occur in the mush of a basalt lava flow. However, the formation of gas bubbles during crystallisation means that the base state includes fluid migration up through the crystal mush even without convection. Stability considerations suggest that it is plausible to form a positive feedback where increased local porosity causes increased upwards fluid flow, which brings more silicic melt up and lowers the liquidus temperature, promoting locally higher porosity. Numerical solutions show that there are steady solutions in which cylinders form, and we conclude that this model provides a viable explanation for vesicular cylinder formation in inflated basalt lava flows.

  18. 43 CFR 37.12 - Confidentiality of cave location information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... administrative review or appeal under 5 U.S.C. 552 or 43 CFR parts 2 or 4. ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Confidentiality of cave location information. 37.12 Section 37.12 Public Lands: Interior Office of the Secretary of the Interior...

  19. Finite element visualization in the cave virtual reality environment

    SciTech Connect

    Plaskacz, E.J.; Kuhn, M.A.

    1996-03-01

    Through the use of the post-processing software, Virtual Reality visualization (VRviz), and the Cave Automatic Virtual Environment (CAVE), finite element representations can be viewed as they would be in real life. VRviz is a program written in ANSI C to translate the mathematical results generated by finite element analysis programs into a virtual representation. This virtual representation is projected into the CAVE environment and the results are animated. The animation is fully controllable. A user is able to translate the image, rotate about any axis and scale the image at any time. The user is also able to freeze the animation at any time step and control the image update rate. This allows the user to navigate around, or even inside, the image in order to effectively analyze possible failure points and redesign as necessary. Through the use of the CAVE and the real life image that is being produced by VRviz, engineers are able to save considerable time, money, and effort in the design process.

  20. 43 CFR 37.12 - Confidentiality of cave location information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... administrative review or appeal under 5 U.S.C. 552 or 43 CFR parts 2 or 4. ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Confidentiality of cave location information. 37.12 Section 37.12 Public Lands: Interior Office of the Secretary of the Interior...

  1. 43 CFR 37.12 - Confidentiality of cave location information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... administrative review or appeal under 5 U.S.C. 552 or 43 CFR parts 2 or 4. ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Confidentiality of cave location information. 37.12 Section 37.12 Public Lands: Interior Office of the Secretary of the Interior...

  2. 43 CFR 37.12 - Confidentiality of cave location information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... administrative review or appeal under 5 U.S.C. 552 or 43 CFR parts 2 or 4. ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Confidentiality of cave location information. 37.12 Section 37.12 Public Lands: Interior Office of the Secretary of the Interior...

  3. 43 CFR 37.12 - Confidentiality of cave location information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... administrative review or appeal under 5 U.S.C. 552 or 43 CFR parts 2 or 4. ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Confidentiality of cave location information. 37.12 Section 37.12 Public Lands: Interior Office of the Secretary of the Interior...

  4. Full Immersive Virtual Environment Cave[TM] in Chemistry Education

    ERIC Educational Resources Information Center

    Limniou, M.; Roberts, D.; Papadopoulos, N.

    2008-01-01

    By comparing two-dimensional (2D) chemical animations designed for computer's desktop with three-dimensional (3D) chemical animations designed for the full immersive virtual reality environment CAVE[TM] we studied how virtual reality environments could raise student's interest and motivation for learning. By using the 3ds max[TM], we can visualize…

  5. 14. Cooper's cave as viewed from the bank of the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Cooper's cave as viewed from the bank of the Hudson River below the Finch, Pruyn & Company Powerhouse. Facing south-southwest. - Glens Falls Dam, 100' to 450' West of U.S. Route 9 Bridge Spanning Hudson River, Glens Falls, Warren County, NY

  6. The Atacama Desert Cave Shredder: A Case for Conduction Thermodynamics

    NASA Astrophysics Data System (ADS)

    Titus, T. N.; Wynne, J. J.; Ruby, D.; Cabrol, N.

    2010-03-01

    In the Atacama Desert, where caves are quite dry, the interior rock temperature should be a function of only the thermal conduction through the rock, which is driven by the mean temperature at the surface. In this paper, we test this hypothesis.

  7. Modelling cave flow hydraulics in the Notranjski Kras, Slovenia

    NASA Astrophysics Data System (ADS)

    Kaufmann, Georg; Gabrovsek, Franci

    2015-04-01

    The Notranjski Kras region is a karst region in western Slovenia, developed in Cretaceous limestone. The region is characterised by hilly relief, with peaks reaching 1300 m elevation. Several well-developed cave systems drain the karst aquifer, providing preferential flow pathes along two sections: The Pivka River, which sinks into Postojnska Jama and reappears in Planinska Jama, and the Stržen and Cerkniščica rivers, which sink into Karlovica Jama, flow through Zelške Jama and Tkalca Jama and also reappear in Planinska Jama. Both sub-surface flow pathes merge in Planinska Jama, providing water for the Unica river. The Unica river leaves Planinska Jama via a large karst srping and passes through Planinsko Polje, disappearing again through two groups of ponors, finally emerging in the Ljubljanka Springs at around 300 m asl. The sub-surface flow path through the Postojnska Jama cave system has been monitored with 7 stations distributed along the flow path, monitoring stage and temperature. We have used the stage data to model flow through the cave system with the program package SWMM, simulating the active parts of Postojnska Jama with simplified geometry. From the comparison of stage observations and predictions, we identified key sections in the cave, which control the sub-surface flow, such as passage constrictions, sumps and by-passes. Using a formal inverse procedure, we determined the geometry of this key sections by fitting predicted to observed stages, and we achieved a very high degree of correlation.

  8. Cryogenic cave carbonates as an archive of Late Pleistocene permafrost in the Ural Mountains: preliminary results

    NASA Astrophysics Data System (ADS)

    Dublyansky, Yuri; Kadebskaya, Olga; Cheng, Hai; Luetscher, Mark; Spötl, Christoph

    2015-04-01

    A specific type of cave deposits, cryogenic cave carbonates (CCCs), was discovered in the late 1980s in several caves of Central Europe. Unlike 'common' speleothems that form primarily due to degassing of CO2 from Ca2+ and HCO3- -rich waters, CCCs form by freezing-induced segregation (Žák et al., 2004). The formation of CCCs, hence, requires the presence of both liquid water and freezing temperatures. The latter combination may occur in caves in two situations: (1) freezing-thawing cycles in cave entrance zones; and (2) degrading permafrost conditions, when the active layer reaches the cave ceiling, whilst the deeper parts of the cave remain frozen. The latter situation is associated with a particular type of CCCs, which can be used as a marker for permafrost conditions. Because cave carbonates can be accurately dated using the U/Th method, CCCs may be used to identify events of (degrading) palaeo-permafrost conditions. In this study, CCCs were identified and sampled in four caves, located along a 1000 km-long transect from the northern to the southern Ural Associating the CCCs to permafrost conditions was possible on the basis of field observations (locations deep inside the cave, far from entrance zones) and stable isotope properties (strongly depleted δ18O values, inverse correlation between δ18O and δ13C). Chaikovskiy et al. (2014) reported five U/Th analyses of CCC from three caves: 16.7 ka and 104.8 ka (Divja Cave, northern Ural); and 13.4 ka, 86.5 ka and 125.3 ka (Rossijskaya and Usvinskaya Caves, central Ural). In this study we report 25 additional U/Th ages from northern and central Ural, as well as the first CCC age from southern Ural (Shulgan-Tash Cave). Most of the younger ages (

  9. On developing thermal cave detection techniques for earth, the moon and mars

    USGS Publications Warehouse

    Wynne, J.J.; Titus, T.N.; Chong, Diaz G.

    2008-01-01

    The purpose of this study is to (1) demonstrate the viability of detecting terrestrial caves at thermal-infrared wavelengths, (2) improve our understanding of terrestrial cave thermal behavior, (3) identify times of day when cave openings have the maximum thermal contrast with the surrounding surface regolith, and (4) further our understanding of how to detect caves on Earth, the Moon and Mars. We monitored the thermal behavior of two caves in the Atacama Desert of northern Chile. Through this work, we identified times when temperature contrasts between entrance and surface were greatest, thus enabling us to suggest optimal overflight times. The largest thermal contrast for both caves occurred during mid-day. One cave demonstrated thermal behavior at the entrance suggestive of cold-trapping, while the second cave demonstrated temperature shifts suggestive of airflow. We also collected thermograms without knowing optimal detection times; these images suggest both caves may also be detectable during off-peak times. We suggest cave detection using thermal remote sensing on Earth and other planetary objects will be limited by (1) capturing imagery in the appropriate thermal wavelength, (2) the size of cave entrance vs. the sensor's spatial resolution, (3) the viewing angle of the platform in relation to the slope trajectory of the cave entrance, (4) the strength of the thermal signal associated with the cave entrance, and (5) the time of day and season of thermal image capture. Through this and other studies, we will begin to identify the range of conditions under which caves are detectable in the thermal infrared and thus improve our detection capabilities of these features on Earth, the Moon and Mars. ?? 2008 Elsevier B.V.

  10. A post-wildfire response in cave dripwater chemistry

    NASA Astrophysics Data System (ADS)

    Nagra, Gurinder; Treble, Pauline C.; Andersen, Martin S.; Fairchild, Ian J.; Coleborn, Katie; Baker, Andy

    2016-07-01

    Surface disturbances above a cave have the potential to impact cave dripwater discharge, isotopic composition and solute concentrations, which may subsequently be recorded in the stalagmites forming from these dripwaters. One such disturbance is wildfire; however, the effects of wildfire on cave chemistry and hydrology remains poorly understood. Using dripwater data monitored at two sites in a shallow cave, beneath a forest, in southwest Australia, we provide one of the first cave monitoring studies conducted in a post-fire regime, which seeks to identify the effects of wildfire and post-fire vegetation dynamics on dripwater δ18O composition and solute concentrations. We compare our post-wildfire δ18O data with predicted dripwater δ18O using a forward model based on measured hydro-climatic influences alone. This helps to delineate hydro-climatic and fire-related influences on δ18O. Further we also compare our data with both data from Golgotha Cave - which is in a similar environment but was not influenced by this particular fire - as well as regional groundwater chemistry, in an attempt to determine the extent to which wildfire affects dripwater chemistry. We find in our forested shallow cave that δ18O is higher after the fire relative to modelled δ18O. We attribute this to increased evaporation due to reduced albedo and canopy cover. The solute response post-fire varied between the two drip sites: at Site 1a, which had a large tree above it that was lost in the fire, we see a response reflecting both a reduction in tree water use and a removal of nutrients (Cl, Mg, Sr, and Ca) from the surface and subsurface. Solutes such as SO4 and K maintain high concentrations, due to the abundance of above-ground ash. At Site 2a, which was covered by lower-middle storey vegetation, we see a solute response reflecting evaporative concentration of all studied ions (Cl, Ca, Mg, Sr, SO4, and K) similar to the trend in δ18O for this drip site. We open a new avenue for

  11. Thorium-230 Dating: Technical Capabilities and Cave Climate Records (Invited)

    NASA Astrophysics Data System (ADS)

    Edwards, R.; Cheng, H.

    2013-12-01

    Because of low natural abundances of Th-230 and U-234, Th-230 dating has been limited by counting statistics ever since the first Th-230 dating studies (Barnes et al., 1956; Broecker, 1963). In this regard, we have made tremendous strides over the past quarter century, increasing the fraction of atoms of U and Th atoms that we can detect by 5 orders of magnitude (from 10-7 to 3x10-2). We have also improved the accuracy and precision of half-life values so that their contribution to uncertainty in Th-230 age is comparable to or smaller than that resulting from analysis uncertainty (Cheng et al., 2013). With ideal samples, we can date materials as old as 800,000 years and the uncertainty in age for a 100,000 year old sample, for example, may be as low as ×100 years (2σ). Given these technical capabilities, the most daunting hurdle is often the ability to find and identify materials amenable to Th-230 dating. Coarsely-crystalline, low-porosity speleothem calcite, containing negligible detrital clay has, in many cases, proven to be ideal in this respect. Over the past 15 years, Th-230 dating of cave calcite has been used to obtain precise chronologies for many cave climate records. Prominent among these are records of the oxygen isotopic composition of cave calcite, which reflect the oxygen isotopic composition of rainfall at the cave site. The most extensive records of this sort are those of the Asian Monsoon based on Chinese cave deposits. Such records now cover over 400,000 years with oxygen isotope resolution averaging several decades. In addition to the fundamental characterization of monsoon history, the records help us to understand the causes in changes in monsoon rainfall. Furthermore, we can correlate cave records to some marine and ice core records, thereby transferring precise cave chronologies to other types of records. Of note is the use of this approach to understand the timing and causes of events during glacial terminations (Cheng et al., 2009). In

  12. Key variables influencing patterns of lava dome growth and collapse

    NASA Astrophysics Data System (ADS)

    Husain, T.; Elsworth, D.; Voight, B.; Mattioli, G. S.; Jansma, P. E.

    2013-12-01

    Lava domes are conical structures that grow by the infusion of viscous silicic or intermediate composition magma from a central volcanic conduit. Dome growth can be characterized by repeated cycles of growth punctuated by collapse, as the structure becomes oversized for its composite strength. Within these cycles, deformation ranges from slow long term deformation to sudden deep-seated collapses. Collapses may range from small raveling failures to voluminous and fast-moving pyroclastic flows with rapid and long-downslope-reach from the edifice. Infusion rate and magma rheology together with crystallization temperature and volatile content govern the spatial distribution of strength in the structure. Solidification, driven by degassing-induced crystallization of magma leads to the formation of a continuously evolving frictional talus as a hard outer shell. This shell encapsulates the cohesion-dominated soft ductile core. Here we explore the mechanics of lava dome growth and failure using a two-dimensional particle-dynamics model. This meshless model follows the natural evolution of a brittle carapace formed by loss of volatiles and rheological stiffening and avoids difficulties of hour-glassing and mesh-entangelment typical in meshed models. We test the fidelity of the model against existing experimental and observational models of lava dome growth. The particle-dynamics model follows the natural development of dome growth and collapse which is infeasible using simple analytical models. The model provides insight into the triggers that lead to the transition in collapse mechasnism from shallow flank collapse to deep seated sector collapse. Increase in material stiffness due to decrease in infusion rate results in the transition of growth pattern from endogenous to exogenous. The material stiffness and strength are strongly controlled by the magma infusion rate. Increase in infusion rate decreases the time available for degassing induced crystallization leading to a

  13. Millennial Scale Cycles from Speleothems of the Gibraltar Caves

    NASA Astrophysics Data System (ADS)

    Boyd, Meighan; Mattey, Dave; Atkinson, Tim; Hoffmann, Dirk

    2016-04-01

    The Rock of Gibraltar contains many solution caves which initially formed near sea level and now span elevations to over 300m as a result of slow uplift over time. In the modern climate, Gibraltar holds an important position near the southern limit of the tracks taken by the depressions that deliver rainfall to Europe from the North Atlantic sector of the atmosphere. Monitoring in St. Michaels and Ragged Staff caves has been carried out since 2004 by monthly sampling and deployment of logging instruments which reveals that speleothem growth is most strongly influenced by seasonally reversing cave ventilation that permeates the entire rock. The results provide unprecedented insight into how cave environments respond to seasonal change, variations in sea level and neotectonic uplift and the ways that regional climate is recorded as chemical proxies in an evolving cave environment. We present an overview of the results of this proxy record of precipitation, sea level and environmental change, including new analysis within this 500ka record. A general mean isotopic composition of 1ka time slices have been stacked into a preliminary record from over twenty speleothems. Within this we look at higher resolution time slices to examine the occurrence of millennial scale cycles which occur within the Gibraltar record. During glacial maxima, the Gibraltar record shows elevated δ18O and associated higher δ13C caused by greater degassing or lower soil pCO2 from weakened vegetative activity during cool arid glacials. Highly resolved millennial scale warming events which seem to match the Greenland ice core record give insights into SST changes and atmospheric reorganization at Gibraltar.

  14. Integrated MVG and ERT Survey Over a Shallow Cave

    NASA Astrophysics Data System (ADS)

    Gambetta, M.; Armadillo, E.; Carmisciano, C.; Stefanelli, P.; Caratori Tontini, F.; Cocchi, L.

    2009-05-01

    An integrated geophysical MVG (Microgravity Vertical Gradient) and ERT (Electrical Resistivity Tomography) survey was performed over a shallow cave in the Armetta Mountain karst area, close to the Liguria-Piedmont watershed (Tanaro valley). The aim of this study is to test the response of a known shallow karst cave. The cave was developed in the Mesozoic sedimentary cover (dolostones and limestones - CAU : Caprauna Armetta Unit); the shallowest portion of the cave exhibits narrow passages and, at about 30 m below the entrance, a fossil meander which links two large chambers, that represent the target of the geophysical survey. The site was surveyed with five, 235 m long, ERT sections, crosscutting the underground voids; 53 MVG stations was collected in an area of 150 by 50 meters above the cave. The ERT prospecting was performed using a Syscal R1 (Iris Instrument) multielectrode system with sets of 48 electrodes evenly spaced each 5 meters. A Wenner-Schlumberger array was used. The MVG survey was performed using a LaCoste&Romberg D model gravity meters equipped with a digital data acquisition through the Aliod feedback system, GPS tracking and automatic tide corrections, with a nominal resolution of 1 microGal (10 nm/s2). Each MVG station was achieved by two successive readings performed at the bottom and top of a 1.80 meters high tower frame. Differential GPS, with acquisition rate of 1 Hz and sampling time of 120 s, was used for the geographic position. The results of the integrated survey show a clear geophysical response of the hollow which exhibits high resistivity values and a negative gravity anomaly. This paper confirms the effectiveness of the geophysical exploration even in a quite complex environment giving a precise location of the voids. The application of such techniques can be efficient in site surveying where the conceivable presence of hollows may be expected.

  15. Mapping planetary caves with an autonomous, heterogeneous robot team

    NASA Astrophysics Data System (ADS)

    Husain, Ammar; Jones, Heather; Kannan, Balajee; Wong, Uland; Pimentel, Tiago; Tang, Sarah; Daftry, Shreyansh; Huber, Steven; Whittaker, William L.

    Caves on other planetary bodies offer sheltered habitat for future human explorers and numerous clues to a planet's past for scientists. While recent orbital imagery provides exciting new details about cave entrances on the Moon and Mars, the interiors of these caves are still unknown and not observable from orbit. Multi-robot teams offer unique solutions for exploration and modeling subsurface voids during precursor missions. Robot teams that are diverse in terms of size, mobility, sensing, and capability can provide great advantages, but this diversity, coupled with inherently distinct low-level behavior architectures, makes coordination a challenge. This paper presents a framework that consists of an autonomous frontier and capability-based task generator, a distributed market-based strategy for coordinating and allocating tasks to the different team members, and a communication paradigm for seamless interaction between the different robots in the system. Robots have different sensors, (in the representative robot team used for testing: 2D mapping sensors, 3D modeling sensors, or no exteroceptive sensors), and varying levels of mobility. Tasks are generated to explore, model, and take science samples. Based on an individual robot's capability and associated cost for executing a generated task, a robot is autonomously selected for task execution. The robots create coarse online maps and store collected data for high resolution offline modeling. The coordination approach has been field tested at a mock cave site with highly-unstructured natural terrain, as well as an outdoor patio area. Initial results are promising for applicability of the proposed multi-robot framework to exploration and modeling of planetary caves.

  16. Reproductive Seasonality in Nesticus (Araneae: Nesticidae) Cave Spiders

    PubMed Central

    Carver, Linnea M.; Perlaky, Patricia; Cressler, Alan; Zigler, Kirk S.

    2016-01-01

    Spiders of the family Nesticidae are members of cave communities around the world with cave-obligate (troglobiotic) species known from North America, Europe, Asia and the Indo-Pacific. A radiation of Nesticus (Araneae: Nesticidae) in the southern Appalachians includes ten troglobiotic species. Many of these species are of conservation interest due to their small ranges, with four species being single-cave endemics. Despite conservation concerns and their important role as predators in cave communities, we know little about reproduction and feeding in this group. We addressed this knowledge gap by examining populations of two species on a monthly basis for one year. We made further observations on several other species and populations, totaling 671 individual spider observations. This more than doubled the reported observations of reproduction and feeding in troglobiotic Nesticus. Female Nesticus carry egg sacs, facilitating the determination of the timing and frequency of reproduction. We found that Nesticus exhibit reproductive seasonality. Females carried egg sacs from May through October, with a peak in frequency in June. These spiders were rarely observed with prey; only 3.3% (22/671) of individuals were observed with prey items. The frequency at which prey items were observed did not vary by season. Common prey items were flies, beetles and millipedes. Troglobiotic species constituted approximately half of all prey items observed. This result represents a greater proportion of troglobiotic prey than has been reported for various troglophilic spiders. Although our findings shed light on the life history of troglobiotic Nesticus and on their role in cave ecosystems, further work is necessary to support effective conservation planning for many of these rare species. PMID:27280416

  17. Reproductive Seasonality in Nesticus (Araneae: Nesticidae) Cave Spiders.

    PubMed

    Carver, Linnea M; Perlaky, Patricia; Cressler, Alan; Zigler, Kirk S

    2016-01-01

    Spiders of the family Nesticidae are members of cave communities around the world with cave-obligate (troglobiotic) species known from North America, Europe, Asia and the Indo-Pacific. A radiation of Nesticus (Araneae: Nesticidae) in the southern Appalachians includes ten troglobiotic species. Many of these species are of conservation interest due to their small ranges, with four species being single-cave endemics. Despite conservation concerns and their important role as predators in cave communities, we know little about reproduction and feeding in this group. We addressed this knowledge gap by examining populations of two species on a monthly basis for one year. We made further observations on several other species and populations, totaling 671 individual spider observations. This more than doubled the reported observations of reproduction and feeding in troglobiotic Nesticus. Female Nesticus carry egg sacs, facilitating the determination of the timing and frequency of reproduction. We found that Nesticus exhibit reproductive seasonality. Females carried egg sacs from May through October, with a peak in frequency in June. These spiders were rarely observed with prey; only 3.3% (22/671) of individuals were observed with prey items. The frequency at which prey items were observed did not vary by season. Common prey items were flies, beetles and millipedes. Troglobiotic species constituted approximately half of all prey items observed. This result represents a greater proportion of troglobiotic prey than has been reported for various troglophilic spiders. Although our findings shed light on the life history of troglobiotic Nesticus and on their role in cave ecosystems, further work is necessary to support effective conservation planning for many of these rare species. PMID:27280416

  18. The role of crystallinity and viscosity in the formation of submarine lava flow morphology

    NASA Astrophysics Data System (ADS)

    McClinton, J. Timothy; White, Scott M.; Colman, Alice; Rubin, Kenneth H.; Sinton, John M.

    2014-09-01

    Submarine lava flow morphology is commonly used to estimate relative flow velocity, but the effects of crystallinity and viscosity are rarely considered. We use digital petrography and quantitative textural analysis techniques to determine the crystallinity of submarine basaltic lava flows, using a set of samples from previously mapped lava flow fields at the hotspot-affected Galápagos Spreading Center. Crystallinity measurements were incorporated into predictive models of suspension rheology to characterize lava flow consistency and rheology. Petrologic data were integrated to estimate bulk lava viscosity. We compared the crystallinity and viscosity of each sample with its flow morphology to determine their respective roles in submarine lava emplacement dynamics. We find no correlation between crystallinity, bulk viscosity, and lava morphology, implying that flow advance rate is the primary control on submarine lava morphology. However, we show systematic variations in crystal size and shape distribution among pillows, lobates, and sheets, suggesting that these parameters are important indicators of eruption processes. Finally, we compared the characteristics of lavas from two different sampling sites with contrasting long-term magma supply rates. Differences between lavas from each study site illustrate the significant effect of magma supply on the physical properties of the oceanic upper crust.

  19. Disruption of tephra fall deposits caused by lava flows during basaltic eruptions

    NASA Astrophysics Data System (ADS)

    Brown, R. J.; Thordarson, T.; Self, S.; Blake, S.

    2015-10-01

    Observations in the USA, Iceland and Tenerife, Canary Islands reveal how processes occurring during basaltic eruptions can result in complex physical and stratigraphic relationships between lava and proximal tephra fall deposits around vents. Observations illustrate how basaltic lavas can disrupt, dissect (spatially and temporally) and alter sheet-form fall deposits. Complexity arises through synchronous and alternating effusive and explosive activity that results in intercalated lavas and tephra deposits. Tephra deposits can become disrupted into mounds and ridges by lateral and vertical displacement caused by movement (including inflation) of underlying pāhoehoe lavas and clastogenic lavas. Mounds of tephra can be rafted away over distances of 100 s to 1,000 s m from proximal pyroclastic constructs on top of lava flows. Draping of irregular topography by fall deposits and subsequent partial burial of topographic depressions by later lavas can result in apparent complexity of tephra layers. These processes, deduced from field relationships, have resulted in considerable stratigraphic complexity in the studied proximal regions where fallout was synchronous or alternated with inflation of subjacent lava sheets. These mechanisms may lead to diachronous contact relationships between fall deposits and lava flows. Such complexities may remain cryptic due to textural and geochemical quasi-homogeneity within sequences of interbedded basaltic fall deposits and lavas. The net effect of these processes may be to reduce the usefulness of data collected from proximal fall deposits for reconstructing basaltic eruption dynamics.

  20. Origin and deformation of high porosity bands in the Takanoobane Rhyolite lava of Aso volcano, Japan

    NASA Astrophysics Data System (ADS)

    Furukawa, K.; Uno, K.

    2015-10-01

    In rhyolite lavas, the high porosity bands are often developed. They potentially act as pathways for gas movement to the lava surface. Since explosive activities of lavas are generally considered to be controlled by degassing system, understanding the origin and deformation process of the high porosity bands is important to assessing volcanic hazards. The Takanoobane rhyolite lava in the middle of Kyushu Island in SW Japan is effused at 51 ± 5 ka. The volume, flow length, and thickness are 0.14 km3, > 2 km, and about 90 m, respectively. The central crystalline part of the lava is characterized by the light-colored bands defined by the high porosity zone (HPZ). On the basis of geological and petrographical studies, we revealed that the HPZ was primary formed by ductile-brittle tearing of the lava (known as cavitation). According to the AMS results, the HPZs were subsequently stretched and flattened laterally during the concentric spreading of the lava. This deformation process could stretch the HPZ not only radially but also laterally. This effective stretching developed the HPZ into pervasive thin bands. Since the HPZs act as degassing pathways to the lava surface, the pervasive HPZ bands may play a role in providing volcanic gasses to void spaces created in surface fold hinges of rhyolite lavas. Thus, this degassing system may promote explosive activity of the lava surface.

  1. Lava flow hazard modeling during the 2014-2015 Fogo eruption, Cape Verde

    NASA Astrophysics Data System (ADS)

    Cappello, Annalisa; Ganci, Gaetana; Calvari, Sonia; Pérez, Nemesio M.; Hernández, Pedro A.; Silva, Sónia V.; Cabral, Jeremias; Del Negro, Ciro

    2016-04-01

    Satellite remote sensing techniques and lava flow forecasting models have been combined to enable a rapid response during effusive crises at poorly monitored volcanoes. Here we used the HOTSAT satellite thermal monitoring system and the MAGFLOW lava flow emplacement model to forecast lava flow hazards during the 2014-2015 Fogo eruption. In many ways this was one of the major effusive eruption crises of recent years, since the lava flows actually invaded populated areas. Combining satellite data and modeling allowed mapping of the probable evolution of lava flow fields while the eruption was ongoing and rapidly gaining as much relevant information as possible. HOTSAT was used to promptly analyze MODIS and SEVIRI data to output hot spot location, lava thermal flux, and effusion rate estimation. This output was used to drive the MAGFLOW simulations of lava flow paths and to continuously update flow simulations. We also show how Landsat 8 OLI and EO-1 ALI images complement the field observations for tracking the flow front position through time and adding considerable data on lava flow advancement to validate the results of numerical simulations. The integration of satellite data and modeling offers great promise in providing a unified and efficient system for global assessment and real-time response to effusive eruptions, including (i) the current state of the effusive activity, (ii) the probable evolution of the lava flow field, and (iii) the potential impact of lava flows.

  2. Discriminating lava flows of different age within Nyamuragira's volcanic field using spectral mixture analysis

    NASA Astrophysics Data System (ADS)

    Li, Long; Canters, Frank; Solana, Carmen; Ma, Weiwei; Chen, Longqian; Kervyn, Matthieu

    2015-08-01

    In this study, linear spectral mixture analysis (LSMA) is used to characterize the spectral heterogeneity of lava flows from Nyamuragira volcano, Democratic Republic of Congo, where vegetation and lava are the two main land covers. In order to estimate fractions of vegetation and lava through satellite remote sensing, we made use of 30 m resolution Landsat Enhanced Thematic Mapper Plus (ETM+) and Advanced Land Imager (ALI) imagery. 2 m Pleiades data was used for validation. From the results, we conclude that (1) LSMA is capable of characterizing volcanic fields and discriminating between different types of lava surfaces; (2) three lava endmembers can be identified as lava of old, intermediate and young age, corresponding to different stages in lichen growth and chemical weathering; (3) a strong relationship is observed between vegetation fraction and lava age, where vegetation at Nyamuragira starts to significantly colonize lava flows ∼15 years after eruption and occupies over 50% of the lava surfaces ∼40 years after eruption. Our study demonstrates the capability of spectral unmixing to characterize lava surfaces and vegetation colonization over time, which is particularly useful for poorly known volcanoes or those not accessible for physical or political reasons.

  3. Constraints on Determining the Eruption Style and Composition of Terrestrial Lavas from Space

    NASA Technical Reports Server (NTRS)

    Wright, Robert; Glaze, Lori; Baloga, Stephen M.

    2011-01-01

    The surface temperatures of active lavas relate to cooling rates, chemistry, and eruption style. We analyzed 61 hyperspectral satellite images acquired by the National Aeronautics and Space Administration s Earth Observing-1 (EO-1) Hyperion imaging spectrometer to document the surface temperature distributions of active lavas erupted at 13 volcanoes. Images were selected to encompass the range of common lava eruption styles, specifically, lava fountains, flows, lakes, and domes. Our results reveal temperature distributions for terrestrial lavas that correlate with composition (i.e., a statistically significant difference in the highest temperatures retrieved for mafic lavas and intermediate and felsic lavas) and eruption style. Maximum temperatures observed for mafi c lavas are approx.200 C higher than for intermediate and felsic lavas. All eruption styles exhibit a low-temperature mode at approx.300 C; lava fountains and 'a' a flows also exhibit a higher-temperature mode at approx.700 C. The observed differences between the temperatures are consistent with the contrasting rates at which the lava surfaces are thermally renewed. Eruption styles that allow persistent and pervasive thermal renewal of the lava surface (e.g., fractured crusts on channel-fed 'a' a flows) exhibit a bimodal temperature distribution; eruption styles that do not (e.g., the continuous skin of pahoehoe lavas) exhibit a single mode. We conclude that insights into composition and eruption style can only be gained remotely by analyzing a large spatio-temporal sample of data. This has implications for determining composition and eruption style at the Jovian moon Io, for which no in situ validation is available.

  4. Controls on lava-snow interactions from propogation styles during the 2012-13 Tolbachik eruption

    NASA Astrophysics Data System (ADS)

    Edwards, Benjamin; Belousov, Alexander; Belousov, Marina

    2014-05-01

    Knowledge of how volcanism interacts with hydrosphere/cryosphere is critical for understanding the functioning and evolution of the Earth, establishing volcanism-climate linkages, and estimations of related hazards. Until now, no special studies have been focused on interactions between snowpack and advancing incandescent lava during volcanic eruptions, even though snow is the most widely distributed form of solid H2O on the planet. It was thought a priori that snow might melt rapidly in front of active lava flows producing vigorous floods. Here we present results of unique field observations made in the snowpack in front of advancing basaltic lava flows during the 2012-13 eruption at Tolbachik volcano, Kamchatka, Russia. Our observations in the first time demonstrate that in reality heat transfer through lava/snow boundary occurs relatively slowly, so that melting of the majority of the snow pack occurs over the span of several hours-days after emplacement of the lava flows, producing only local and sporadic meltwater floods. Two fundamentally different styles of lava propagation result in two strikingly different responses of snowpack: i) 'a'a lava advancing in a rolling caterpillar-track motion propagates on top of snowpack; the melt water accumulates in (saturates) the layer of snow buried underneath the lava flow and does not interact notably with the lava material, and ii) pahoehoe lava advancing as inflating lobes propagates beneath/inside snowpack, locally generating slowly growing 'snow-domes'; the melt water precipitates down into incandescent lava producing chilling and local thermal shock/quench fragmentation (minor hyaloclastite production). Our observations show that lava-snow interactions can vary significantly depending on styles of flow front advance. Lava flows emplaced over areas covered with snow bear features that can be distinguished in old stratigraphic sequences and used for paleoclimatic reconstructions on Earth, Mars and other planets.

  5. Oxygen isotope geochemistry of back-arc lavas

    NASA Astrophysics Data System (ADS)

    Bonifacie, M.; Eiler, J. M.; Stolper, E. M.; Langmuir, C. H.

    2007-12-01

    Oxygen isotope ratios of arc-related magmas can constrain the amount and nature of slab-derived components contributing to their mantle sources because: (i) most geological solids and fluids contain similar concentration of oxygen; and (ii) possible slab components (fluids, melts or rocks from sedimentary, mafic or ultramafic parts of the lithosphere) differ from one another in δ18O values and these distinctive oxygen-isotope compositions can be preserved in deeply subducted materials. Previous laser fluorination oxygen isotope data on back-arc basin basalts (BABB) show slightly but consistently elevated δ18O values (from 5.5 to 6.1 ‰ [1-3]) with respect to mid-ocean ridge basalts or MORB (δ18O = 5.5 ± 0.2 ‰ [4]). The subtle elevations in δ18O characteristic of BABB are generally associated with 'enriched' radiogenic isotope compositions (e.g., high 87Sr/86Sr) and high apparent degrees of melting of their peridotitic sources that may reflect fluxed melting of the mantle by fluids and/or hydrous melts released from subducted oceanic lithosphere [1-3]. These trends could be used to precisely define the sources and amounts of slab- derived components delivered to the back arc mantle. However, two issues demand that this problem be better constrained through further studies. First, the subtle difference in δ18O between MORB and BABB involves comparison of data generated in different laboratories that may not share common standardization; this difference must be demonstrated within a single laboratory using a common set of standards. Second, the trends of δ18O vs. other geochemical indices observed in BABB lavas are based on samples from several relatively small and unrelated suites of lavas. These trends must be documented through study of one or more relatively large and diverse suites of closely related lavas. We are performing new laser-fluorination oxygen isotope measurements of a comprehensive suite of fresh back-arc glasses collected along the Eastern

  6. Asymmetric deformation structure of lava spine in Unzen Volcano, Japan

    NASA Astrophysics Data System (ADS)

    Miwa, T.; Okumura, S.; Matsushima, T.; Shimizu, H.

    2013-12-01

    Lava spine is commonly generated by effusive eruption of crystal-rich, dacitic-andesitic magmas. Especially, deformation rock on surface of lava spine has been related with processes of magma ascent, outgassing, and generation of volcanic earthquake (e.g., Cashman et al. 2008). To reveal the relationships and generation process of the spine, it is needed to understand a spatial distribution of the deformation rock. Here we show the spatial distribution of the deformation rock of lava spine in the Unzen volcano, Japan, to discuss the generation process of the spine. The lava spine in Unzen volcano is elongated in the E-W direction, showing a crest like shape with 150 long, 40 m wide and 50 m high. The lava spine is divided into following four parts: 1) Massive dacite part: Dense dacite with 30 m of maximum thickness, showing slickenside on the southern face; 2) Sheared dacite part: Flow band developed dacite with 1.0 m of maximum thickness; 3) Tuffisite part: Network of red colored vein develops in dacite with 0.5 m of maximum thickness; 4) Breccia part: Dacitic breccia with 10 m of maximum thickness. The Breccia part dominates in the northern part of the spine, and flops over Massive dacite part accross the Sheared dacite and Tuffisite parts. The slickenside on southern face of massive dacite demonstrates contact of solids. The slickenside breaks both of phenocryst and groundmass, demonstrating that the slickenside is formed after significant crystallization at the shallow conduit or on the ground surface. The lineation of the slickenside shows E-W direction with almost horizontal rake angle, which is consistent with the movement of the spine to an east before emplacement. Development of sub-vertical striation due to extrusion was observed on northern face of the spine (Hayashi, 1994). Therefore, we suggest that the spine just at extrusion consisted of Massive dacite, Sheared dacite, Tuffisite, Breccia, and Striation parts in the northern half of the spine. Such a

  7. [Variation Characteristics of Cave Water Hydrogeochemistry in Naduo Cave of Guizhou and Its Implications for Environment Research].

    PubMed

    Shen, Wei; Wang, Jian-li; Wang, Jia-lu; Jiang, Xian-shu; Mao, Qing-ya; Chen, Zhi-qiu; Liu, Xiao

    2015-12-01

    During the period from December 2012 to December 2014, three dripping water sites (S1, S2, S3) and one pool water site (SC) have been selected for a long-term monitoring of geochemical indexes in Naduo Cave, Guanling county of Guizhou Province, China. Based on the local meteorological data, this paper analyzed the seasonal change of hydro-geochemical indicators and their feedbacks to climate events. The results indicated that the hydro-geochemical type of cave water was HCO₃⁻-Ca²⁺. Dripping water and pool water were in deposition all the year, except in the month with the maximum precipitation. There were some discrepancies of main ions' concentration among three dripping water sites due to the difference of the migration pathways and migration time. Affected by mixed water and high CO₂ concentration of cave air, the ion concentration of pool water was higher than dripping water, and there was considerable fluctuation. The geochemistry indexes of water in Naduo Cave showed extraordinary seasonal variation rules and could perfectly respond to the external climate environment. The concentration of ions was sensitive to the response of the annual precipitation change caused by extreme climate events. During the rainy season, the concentrations of Ca²⁺, Mg²⁺ and SO₄²⁻ in 2013 were relatively higher and more stable than those in 2014. The response time and susceptivity of each monitoring site were inconsistent. PMID:27011980

  8. First DNA sequences from Asian cave bear fossils reveal deep divergences and complex phylogeographic patterns.

    PubMed

    Knapp, Michael; Rohland, Nadin; Weinstock, Jacobo; Baryshnikov, Gennady; Sher, Andrei; Nagel, Doris; Rabeder, Gernot; Pinhasi, Ron; Schmidt, Heiko A; Hofreiter, Michael

    2009-03-01

    Until recently, cave bears were believed to have only inhabited Europe. However, recent morphological evidence suggests that cave bears' geographic range extended as far east as Transbaikalia, Eastern Siberia. These Asian cave bears were morphologically distinct from European cave bears. However, how they related to European lineages remains unclear, stressing the need to assess the phylogenetic and phylogeographic relationship between Asian cave bears and their European relatives. In this work, we address this issue using a 227 base-pair fragment of the mitochondrial control region obtained from nine fossil bone samples from eight sites from the Urals, Caucasus, Altai Mountains, Ukraine and Yana River region in Eastern Siberia. Results of the phylogenetic analyses indicate that (i) the cave bear from the Yana River is most closely related to cave bears from the Caucasus region; (ii) the Caucasus/Yana group of bears is genetically very distinct from both European cave bears and brown bears, suggesting that these bears could represent an independent species; and (iii) the Western European cave bear lineage reached at least temporarily to the Altai Mountains, 7000 km east of their known centre of distribution. These results suggest that the diversity of cave bears was greater than previously believed, and that they could survive in a much wider range of ecological conditions than previously assumed. They also agree with recent studies on other extinct and extant species, such as wolves, hyenas and steppe bison, which have also revealed higher genetic and ecological diversity in Pleistocene populations than previously known. PMID:19226321

  9. Dating cave speleothems using diamond core bits in Tennessee and Virginia

    NASA Astrophysics Data System (ADS)

    Burnham, T. G.; Gao, Y.; Cheng, H.; Edwards, R.

    2011-12-01

    Removing speleothems for paleoclimate study was a destructive practice in cave and karst communities. It was considered illegal and even resulted in lawsuits in some cases. We used small diamond core bits to investigate age distributions of speleothems in several caves in Virginia and Tennessee without removing them from caves. Core bits of 8 mm diameter and one inch depth of cut were used to drill nearly 100 cores from three caves: Morril's Cave (aka Worley's Cave) and Blue Springs Cave in Tennessee and Grand Caverns in Virginia. Samples drilled in Morrill's Cave were processed for U/Th chemistry directly. Cores drilled in Blue Springs Cave and Grand Caverns were carefully selected and cleaned using ultrasonic cleaner before the U/Th chemistry procedure. Age dating results showed significant differences for these two sets of samples. For Morril's Cave samples, most of the age errors (2 sigma) were greater than 1%. For the pre-cleaned samples, more than 90% of the age errors (2 sigma) were less than 1%. This method is non-destructive and easy to use with minimum equipment needed in the field. Age dating results are fairly precise if samples are pre-cleaned for U/Th chemistry. Major limitations of this methods are 1) Pre-cleaning is necessary to ensure precise dating results; 2) Hiatus could be missed if cores are only drilled at the top and bottom portions of the speleothems; 3) Exact location of ages are hard to interpret especially for relatively longer cores.

  10. Particle fuel bed tests

    SciTech Connect

    Horn, F.L.; Powell, J.R.; Savino, J.M.

    1985-01-01

    Gas-cooled reactors, using packed beds of small diameter coated fuel particles have been proposed for compact, high-power systems. The particulate fuel used in the tests was 800 microns in diameter, consisting of a thoria kernel coated with 200 microns of pyrocarbon. Typically, the bed of fuel particles was contained in a ceramic cylinder with porous metallic frits at each end. A dc voltage was applied to the metallic frits and the resulting electric current heated the bed. Heat was removed by passing coolant (helium or hydrogen) through the bed. Candidate frit materials, rhenium, nickel, zirconium carbide, and zirconium oxide were unaffected, while tungsten and tungsten-rhenium lost weight and strength. Zirconium-carbide particles were tested at 2000 K in H/sub 2/ for 12 hours with no visible reaction or weight loss.

  11. Bed rest during pregnancy

    MedlinePlus

    ... provider before you start any activity: Squeezing stress balls Pressing your hands and feet against the bed ... limit yourself from doing any of these: Cooking Light chores Walking Bathing or showering Driving Having sex ...

  12. Tapered bed bioreactor

    DOEpatents

    Scott, Charles D.; Hancher, Charles W.

    1977-01-01

    A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

  13. Test Bed For Telerobots

    NASA Technical Reports Server (NTRS)

    Matijevic, Jacob R.; Zimmerman, Wayne F.; Dolinsky, Shlomo

    1990-01-01

    Assembly of electromechanical and electronic equipment (including computers) constitutes test bed for development of advanced robotic systems for remote manipulation. Combines features not found in commercial systems. Its architecture allows easy growth in complexity and level of automation. System national resource for validation of new telerobotic technology. Intended primarily for robots used in outer space, test bed adapted to development of advanced terrestrial telerobotic systems for handling radioactive materials, dangerous chemicals, and explosives.

  14. ‘Neanderthal bone flutes’: simply products of Ice Age spotted hyena scavenging activities on cave bear cubs in European cave bear dens

    PubMed Central

    Diedrich, Cajus G.

    2015-01-01

    Punctured extinct cave bear femora were misidentified in southeastern Europe (Hungary/Slovenia) as ‘Palaeolithic bone flutes’ and the ‘oldest Neanderthal instruments’. These are not instruments, nor human made, but products of the most important cave bear scavengers of Europe, hyenas. Late Middle to Late Pleistocene (Mousterian to Gravettian) Ice Age spotted hyenas of Europe occupied mainly cave entrances as dens (communal/cub raising den types), but went deeper for scavenging into cave bear dens, or used in a few cases branches/diagonal shafts (i.e. prey storage den type). In most of those dens, about 20% of adult to 80% of bear cub remains have large carnivore damage. Hyenas left bones in repeating similar tooth mark and crush damage stages, demonstrating a butchering/bone cracking strategy. The femora of subadult cave bears are intermediate in damage patterns, compared to the adult ones, which were fully crushed to pieces. Hyenas produced round–oval puncture marks in cub femora only by the bone-crushing premolar teeth of both upper and lower jaw. The punctures/tooth impact marks are often present on both sides of the shaft of cave bear cub femora and are simply a result of non-breakage of the slightly calcified shaft compacta. All stages of femur puncturing to crushing are demonstrated herein, especially on a large cave bear population from a German cave bear den. PMID:26064624

  15. 'Neanderthal bone flutes': simply products of Ice Age spotted hyena scavenging activities on cave bear cubs in European cave bear dens.

    PubMed

    Diedrich, Cajus G

    2015-04-01

    Punctured extinct cave bear femora were misidentified in southeastern Europe (Hungary/Slovenia) as 'Palaeolithic bone flutes' and the 'oldest Neanderthal instruments'. These are not instruments, nor human made, but products of the most important cave bear scavengers of Europe, hyenas. Late Middle to Late Pleistocene (Mousterian to Gravettian) Ice Age spotted hyenas of Europe occupied mainly cave entrances as dens (communal/cub raising den types), but went deeper for scavenging into cave bear dens, or used in a few cases branches/diagonal shafts (i.e. prey storage den type). In most of those dens, about 20% of adult to 80% of bear cub remains have large carnivore damage. Hyenas left bones in repeating similar tooth mark and crush damage stages, demonstrating a butchering/bone cracking strategy. The femora of subadult cave bears are intermediate in damage patterns, compared to the adult ones, which were fully crushed to pieces. Hyenas produced round-oval puncture marks in cub femora only by the bone-crushing premolar teeth of both upper and lower jaw. The punctures/tooth impact marks are often present on both sides of the shaft of cave bear cub femora and are simply a result of non-breakage of the slightly calcified shaft compacta. All stages of femur puncturing to crushing are demonstrated herein, especially on a large cave bear population from a German cave bear den. PMID:26064624

  16. A meta-analysis of aneurysm formation in laser assisted vascular anastomosis (LAVA)

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. However, aneurysm formation is one of the main reasons delay the clinical application of LAVA. Some scientists investigated the incidence of aneurysms in animal model. To systematically analyze the literature on reported incidence of aneurysm formation in LAVA therapy, we performed a meta-analysis comparing LAVA with conventional suture anastomosis (CSA) in animal model. Data were systematically retrieved and selected from PUBMED. In total, 23 studies were retrieved. 18 studies were excluded, and 5 studies involving 647 animals were included. Analysis suggested no statistically significant difference between LAVA and CSA (OR 1.24, 95%CI 0.66-2.32, P=0.51). Result of meta analysis shows that the technology of LAVA is very close to clinical application.

  17. Temperature Measurements in Carbonatite Lava Lakes and Flows from Oldoinyo Lengai, Tanzania

    NASA Astrophysics Data System (ADS)

    Krafft, Maurice; Keller, Jorg

    1989-07-01

    The petrogenesis of carbonatites has important implications for mantle processes and for the magmatic evolution of mantle melts rich in carbon dioxide. Oldoinyo Lengai, Tanzania, is