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1

Rocks, Weathering, and Erosional Landscapes  

NSDL National Science Digital Library

Students will identify principal rock forming silicate minerals and distinguish their relative stability when exposed to weathering; identify sedimentary, igneous and metamorphic rocks and deduce the relative resistance based on mineral composition and texture;and finally relate erosional landscapes to the differential weathering and erosion of rocks of varying strengths. Designed for a geomorphology course

Hanson, Lindley

2

Chemical weathering indices applied to weathering profiles developed on heterogeneous felsic metamorphic parent rocks  

Microsoft Academic Search

Chemical weathering indices are commonly used for characterizing weathering profiles by incorporating bulk major element oxide chemistry into a single metric for each sample. Generally, on homogeneous parent rocks, weathering indices change systematically with depth. However, the weathering of heterogeneous metamorphic rocks confounds the relationship between weathering index and depth. In this paper, we evaluate previously defined chemical weathering indices

Jason R Price; Michael A Velbel

2003-01-01

3

Take a Tumble: Weathering and Erosion Using a Rock Tumbler  

ERIC Educational Resources Information Center

|Weathering--the physical and chemical breakdown of geologic materials--and erosion--the transport of materials by wind, water, or ice--can be subtle, yet powerful forces. For example, shale, a rock made of mud-sized particles, is by far the most common sedimentary rock, a testament to the ability of weathering and erosion to take a rock and…

Coffey, Patrick; Mattox, Steve

2006-01-01

4

Bibliography on the Chemical Weathering of Granitic Rocks,  

National Technical Information Service (NTIS)

This bibliography lists many of the papers in the international published geological geomorphological and soils literature that discuss the chemical weathering of rocks often considered non-soluble. Emphasis is placed on granitic rocks. Keywords: Chemical...

A. J. Gerrard J. Ehlen

1988-01-01

5

Rock-weathering rates as functions of time  

USGS Publications Warehouse

The scarcity of documented numerical relations between rock weathering and time has led to a common assumption that rates of weathering are linear. This assumption has been strengthened by studies that have calculated long-term average rates. However, little theoretical or empirical evidence exists to support linear rates for most chemical-weathering processes, with the exception of congruent dissolution processes. The few previous studies of rock-weathering rates that contain quantitative documentation of the relation between chemical weathering and time suggest that the rates of most weathering processes decrease with time. Recent studies of weathering rinds on basaltic and andesitic stones in glacial deposits in the western United States also clearly demonstrate that rock-weathering processes slow with time. Some weathering processes appear to conform to exponential functions of time, such as the square-root time function for hydration of volcanic glass, which conforms to the theoretical predictions of diffusion kinetics. However, weathering of mineralogically heterogeneous rocks involves complex physical and chemical processes that generally can be expressed only empirically, commonly by way of logarithmic time functions. Incongruent dissolution and other weathering processes produce residues, which are commonly used as measures of weathering. These residues appear to slow movement of water to unaltered material and impede chemical transport away from it. If weathering residues impede weathering processes then rates of weathering and rates of residue production are inversely proportional to some function of the residue thickness. This results in simple mathematical analogs for weathering that imply nonlinear time functions. The rate of weathering becomes constant only when an equilibrium thickness of the residue is reached. Because weathering residues are relatively stable chemically, and because physical removal of residues below the ground surface is slight, many weathering features require considerable time to reach constant rates of change. For weathering rinds on volcanic stones in the western United States, this time is at least 0.5 my. ?? 1981.

Colman, S. M.

1981-01-01

6

Image analysis for quantification of bacterial rock weathering.  

PubMed

A fast, quantitative image analysis technique was developed to assess potential rock weathering by bacteria. The technique is based on reduction in the surface area of rock particles and counting the relative increase in the number of small particles in ground rock slurries. This was done by recording changes in ground rock samples with an electronic image analyzing process. The slurries were previously amended with three carbon sources, ground to a uniform particle size and incubated with rock weathering bacteria for 28 days. The technique was developed and tested, using two rock-weathering bacteria Pseudomonas putida R-20 and Azospirillum brasilense Cd on marble, granite, apatite, quartz, limestone, and volcanic rock as substrates. The image analyzer processed large number of particles (10(7)-10(8) per sample), so that the weathering capacity of bacteria can be detected. PMID:15982765

Puente, M Esther; Rodriguez-Jaramillo, M Carmen; Li, Ching Y; Bashan, Yoav

2005-06-27

7

Rock-based measurement of temperature-dependent plagioclase weathering  

Microsoft Academic Search

Long-term ( > 105 years) weathering can be quantified by measuring microsopic dissolution of minerals in exposed rock surfaces. Digital backscattered (BSE) electron microscope images of plagioclase porosity in field exposures of known age resolves weathering at finer scales and over longer time spans than conventional solute budget and laboratory studies. Rock-based BSE imaging is therefore a potentially useful tool

Ronald I. Dorn; Patrick V. Brady

1995-01-01

8

Rock-weathering by lichens in Antarctic: patterns and mechanisms  

Microsoft Academic Search

Saxicolous species of lichens are able to induce and accelerate weathering of their rock substrate, and effects of lichens\\u000a on substrate can be attributed to both physical and chemical causes. This paper is focused on biotic weathering actions of\\u000a epilithic and endolithic species on the different rock types (sandstones and volcanogenic rocks) in Antarctica. The patterns,\\u000a mechanisms, processes and neoformations

Chen Jie; Hans-Peter Blume

2002-01-01

9

Science Sampler: Chemical weathering--Where did the rocks go?  

NSDL National Science Digital Library

This lesson is part of a larger Earth science unit that combines the concepts of the rock cycle and the water cycle and how they interact to change landforms. The authors refer to it as the "make it and then break it" unit. They spend half the unit making metamorphic, sedimentary, and igneous rock models, and the second half of the unit weathering and eroding their models and other rocks. Students use the lessons learned to answer an open-ended question describing the process of weathering. They also make decisions regarding the chemical and mechanical weathering on monuments and buildings.

Wallace, Carolyn; Zawicki, Joseph; Harris, Robin

2008-10-01

10

Relationships Between Magnetic Properties and Weathering Indices of Basaltic Rocks  

NASA Astrophysics Data System (ADS)

Performance of geophysical sensors is often hampered by soils and regolith with significant levels of magnetic susceptibility and viscosity, primarily dependent on the amount and form of ferrimagnetic iron oxide minerals present. In order to develop predictive models for the occurrence of such conditions, it is crucial to understand how the magnetic signal evolves during weathering from fresh rock to soil material. Rock weathering leads to destruction of primary minerals, formation of secondary minerals, and concomitant changes in magnetic properties and major-, minor-, and trace-element geochemistry. Previous work has examined relationships between magnetic properties (e.g., magnetic susceptibility) and single-element proxies for overall sample weathering state. In this contribution we study the relationships between bulk geochemical and magnetic characteristics of weathered basaltic rock, and regolith and soils with basaltic parent material. Four samples collected from a corestone formed by spheroidal weathering on the Kohala Peninsula on the Big Island of Hawaii represent the earliest stages of weathering; a series of samples from regolith to the B-horizon for a soil on Kaho'olawe Island represent later weathering stages. Our analysis includes X-Ray Fluorescence Spectroscopy of whole-sample geochemistry and magnetic measurements for a range of temperatures and frequencies. The extent of chemical weathering is assessed by use of a number of common (but Fe-free) major-element weathering indices. Progressive spheroidal weathering involves centripetal migration of a weathering front from joints and fractures into the interior of the joint blocks. As the weathering front passes through a volume of material, fresh or slightly weathered rock is transformed to a primary-mineral-depleted, clay-rich shell. The exfoliated shells farthest from the corestone were the first weathered; shells successively closer to the corestone were more recently transformed. In the Kohala corestone-shell complex, some chemical-weathering indices vary monotonically with total Fe (as Fe2O3), whereas other chemical-weathering indices vary monotonically with magnetic susceptibility. Thus, some Fe-free major-element chemical-weathering indices seem to scale more systematically with soil magnetic properties than others. For more strongly weathered soils from Kaho'olawe, there is a weak relationship between magnetic properties and total Fe. We hope that through the use of Fe-free major-element weathering indices an improved relationship can be developed. Such an improved correlation would benefit phenomenological understanding of geophysical sensor performance in areas with basaltic substrate.

van Dam, R. L.; Velbel, M. A.

2009-05-01

11

Plant-induced weathering of a basaltic rock: experimental evidence  

Microsoft Academic Search

The active role of higher plants in the weathering of silicate minerals and rocks is still a question for debate. The present work aimed at providing experimental evidence of the important role of a range of crop plants in such processes. In order to quantitatively assess the possible effect of these diverse plant species on the weathering of a basaltic

Philippe Hinsinger; Omar Neto Fernandes Barros; Marc F. Benedetti; Yves Noack; Gabriel Callot

2001-01-01

12

Association of trace elements with iron oxides during rock weathering  

Microsoft Academic Search

The association of trace elements with Fe oxides during the early stages of rock weathering was determined by analysis of fresh diabase and granite rocks, their associated whole and size-separated saprolites, and goethite by neutron activation and X-ray fluorescence. The same elements are found to be associated with Fe oxides when the results are interpreted by analysis of correlation, by

R. D. Koons; P. A. Helmke; M. L. Jackson

1980-01-01

13

Weathering  

NSDL National Science Digital Library

This course handout covers the processes and effects of weathering. The purpose of this handout is to contrast weathering and erosion, contrast and discuss chemical and mechanical weathering, list the products resulting from the chemical weathering of igneous rocks, and list and discuss the factors that influence the type and rate of rock weathering. Many photographs accompany this summary which depict weathered landscapes. Links are provided to the online Physical Geology resources at Georgia Perimeter College.

Gore, Pamela

1995-08-29

14

Weathering of Rocks Under Humid Tropical Conditions.  

National Technical Information Service (NTIS)

Bauxite formation in the Pengerang Area of southeast Peninsula Malaysia is the end-product of the insitu weathering of Triassic feldspar-rich rhyolitic to andesitic lavas, tuffs and granophyre, under warm humid climatic conditions. The dominant minerals i...

C. S. Hutchison

1973-01-01

15

Weathering of rock surfaces in the Zermatt-Saas area (Swiss Alps), weathering rinds resulting from water-rock interaction  

NASA Astrophysics Data System (ADS)

The geogene component of the chemical composition of most surface waters is contributed by interaction of precipitation water with silicate rocks exposed in the catchment. Mineral solubility and rates of dissolution reaction control the water-rock interaction process. We have studied the chemical composition of surface waters and weathering crusts of exposed rocks in high Alpine catchments of the Zermatt-Saas area (Swiss Alps). Surface water in this area is predominantly controlled by the interaction of meteoric water with the exposed rocks. Water-rock interaction acquires solutes for the surface waters but also chemically and mineralogically alters the near surface volume of the exposed rocks. Exposed rocks in Zermatt-Saas area include various metamorphic oceanic rocks of the Zermatt-Saas ophiolite unit (ZSU) and continental rocks of the nappes above and below the ZSU. During early stages of Alpine orogeny, the ZSU has been subducted and transformed to eclogites and other high-pressure rocks. Fragments of the oceanic material were returned to the surface as serpentinites, eclogites, eclogite facies metagabbro and metasediments. At many outcrops exposed rocks show distinct signs of surface alteration and are coated with rust-colored weathering crusts. These crusts often display a rough surface texture and are porous as a result of intense chemical weathering. For the purpose of this study we collected typical samples of strongly weathered common rocks of the area, including serpentinite, greenschist and gneiss. The sampling locations were typically close to bodies of surface water. We found that the penetration depth of the interaction between surface water and exposed rocks ranges from 0 - 20 mm. In some strongly altered rocks the interface of the alteration reaction between altered and fresh rock was located several cm below the surface. The presence and thickness of reaction crusts is limited by access of water to the reaction sites (reaction front), specifically to the amount of reaction-created porosity and other water-conducting features. Six pairs of carefully separated weathered and fresh parts of rocks were analyzed by X-ray fluorescence to study the bulk composition evolution. 15 thin sections from the weathered part of the rock samples were examined by microscopy. Clear alteration textures were observed on most reactive minerals, like olivine, chlorite, serpentine, pyrite and others. Reaction related chemical changes of such minerals were analyzed by electron microprobe. Weathered rocks from the same lithology have texturally and chemically very similar alteration crusts throughout the area. In metabasaltic rocks like greenschist, chlorite was found to be very finely intergrown with Fe-oxyhydroxide on a µm scale in the alteration zone close to and at the weathered surface. In ultramafic rocks like serpentinite, the alteration from olivine to chrysotile was commonly found. The bulk composition differences between weathered and fresh parts of the rock samples can be correlated with the chemical characteristics of surface water from the respective catchments.

Zhou, Wei; Bucher, Kurt

2010-05-01

16

Weathering of rocks induced by lichen colonization — a review  

Microsoft Academic Search

The evidence presented by numerous investigations of the interface between lichens and their rock substrates strongly suggests that the weathering of minerals can be accelerated by the growth of at least some lichen species. The effects of lichens on their mineral substrates can be attributed to both physical and chemical processes. The physical effects are reflected by the mechanical disruption

Jie Chen; Hans-Peter Blume; Lothar Beyer

2000-01-01

17

Reassessment of chemical weathering indices: case study on pyroclastic rocks of Hong Kong  

Microsoft Academic Search

Quantitative and objective characterization of weathered states of rock by means of chemical weathering indices has significant potential in ground investigation practice. This paper reviews more than thirty different chemical indices and re-assesses their variations along a weathered profile developed over pyroclastic rocks under subtropical conditions. Chemical weathering indices are principally based on the basic assumption that distributions of chemical

N. S Duzgoren-Aydin; A Aydin; J Malpas

2002-01-01

18

Weathered stony meteorites from Victoria Land, Antarctica, as possible guides to rock weathering on Mars  

NASA Astrophysics Data System (ADS)

Parallel studies of Martian geomorphic features and their analogs on Earth continue to be fruitful in deciphering the geologic history of Mars. In the context of rock weathering, the Earth-analog approach is admirably served by the study of meteorites recovered from ice sheets in Antarctica. The weathering environment of Victoria Land possesses several Mars-like attributes. Four of the five Antarctic meteorites being studied contain rust and EETA79005 further possesses a conspicuous, dark, weathering rind on one side. Secondary minerals (rust and salts) occur both on the surfaces and interiors of some of the samples and textural evidence indicates that such secondary mineralization contributed to physical weathering (by salt riving) of the rocks. Several different rust morphologies occur and emphasis is being placed on identifying the phase compositions of the various rust occurrances. A thorough understanding of terrestrial weathering features of the meteorites is a prerequisite for identifying possible Martian weathering features (if such features exist) that might be postulated to occur in some meteorites.

Gooding, J. L.

1984-04-01

19

Weathering distribution in a steep slope of soft pyroclastic rocks as an indicator of slope instability  

Microsoft Academic Search

Weathering of rocks on steep slopes influences slope instability and sometimes leads to slope failure during heavy rainfall. To determine the weathering intensity of hillslope rocks and its inward change from the slope surface, measurements of the penetrative hardness of rocks, which correlates with their strength, were made in some slopes composed of soft pyroclastic rocks on Kyushu Island, Japan.

S. Yokota; A. Iwamatsu

2000-01-01

20

Index properties of weathered rocks: inter-relationships and applicability  

Microsoft Academic Search

The paper describes the change in physical and strength properties due to weathering of three crystalline rocks – granite,\\u000a basalt and quartzite. It draws attention to the relationship between unconfined compressive strength and other measurements\\u000a such as the point load index, the Brazilian tensile strength and the Schmidt hammer rebound number. The strength recorded\\u000a is negatively related to the porosity

A. S. Gupta; K. Seshagiri Rao

1998-01-01

21

Influence of weathering on the engineering properties of Harsit granitic rocks (NE Turkey)  

Microsoft Academic Search

Weathering and hydrothermal alteration of the granitic rocks in the Eastern Black Sea Region (NE Turkey) are important phenomena\\u000a affecting the engineering projects in the region. The study investigated the probable paths of rock-forming mineral transformations\\u000a due to weathering in the Harsit granitoid rocks, the changes of the major oxides as a consequence of weathering and the effects\\u000a of weathering

Sener Ceryan; Sule Tudes; Nurcihan Ceryan

2008-01-01

22

The thermal responses of rock art pigments: Implications for rock art weathering in southern Africa  

NASA Astrophysics Data System (ADS)

The San rock art of southern Africa is an international heritage subject to degradation and loss resulting from weathering. The paintings occur within rock shelters, where many are exposed to direct solar radiation for varying periods, rather than occurring in dark caves. As part of a study on the factors thought to be impacting weathering, data were collected pertaining to rock and pigment temperatures as well as humidity within the rock shelters. In addition, XRD analyses were undertaken on pigment samples, and the pigment to rock and pigment to pigment contacts were investigated by means of SEM. Pigments were found to be composed of ferric oxide (the ochre) and a gypsum-clay mix (the white) and to occur as a layer on top of, rather than penetrating into, the sandstone. Noncontact infrared sensors were used to monitor the temperatures of the actual pigments while micro-thermocouples to monitor the surrounding (nonpainted) rock surfaces. Thermal data show that there are significant differences between the white and the ochre pigments, both in terms of actual temperatures and short-term thermal responses. Noticeably, the white paint exhibits (relatively) large thermal fluctuations, as compared to the ochre or the rock, over the 20-s to 1-min timescale; these thermal variations may induce pigment-to-pigment stresses within the painting. The pigmented areas also exhibit different temperatures to the surrounding paint-free rock, suggesting that there may be both within-painting and between painting and rock (including the rock beneath the painting) stresses that can lead to degradation. Humidity data were found to be inadequate for any meaningful evaluation of the moisture conditions.

Hall, Kevin; Meiklejohn, Ian; Arocena, Joselito

2007-10-01

23

Weathering of expansive sedimentary rock due to cycles of wetting and drying  

Microsoft Academic Search

There are several different mechanisms by which sedimentary rock can weather, such as: (1) Rebound: for cut areas, where the overburden has been removed by erosion or during mass-grading operations, the sedimentary rock will rebound due to the release in overburden pressure, the rebound can cause the opening or widening of cracks and joints; (2) Physical Weathering: sedimentary rock can

Day

1994-01-01

24

Investigating sedimentary rock deposition and weathering in Mawikwe Bay Sea Caves  

NSDL National Science Digital Library

A field investigation to the Mawikwe Bay Sea Caves of northern Wisconsin along Lake Superior in the winter. Students will investigate deposition of sedimentary rocks and weathering of the rocks to produce sea caves.

25

Effects of Weathering on Basaltic Rocks and Their Thermal Emission Spectra: Implications for Evaluating Mars Mineralogy and Weathering  

NASA Astrophysics Data System (ADS)

Thermal emission spectroscopy has provided crucial information about the mineralogical composition of the Martian surface. Portions of that surface may be chemically weathered, and it is, therefore, important that the influence of chemical weathering on thermal infrared observations be recognized and understood. To this end, we have examined a suite of weathered rocks collected from the Columbia River Basalt Group. Weathering causes distinct changes to the thermal emissivity spectra of these basalts, which will be discussed in detail by J. R. Michalski et al. (this meeting). Here, we document physical and mineralogical features of weathering rinds to understand how weathering affects infrared spectra. Chemical weathering of basalts forms microcracks, dissolves primary minerals, and produces secondary phases. In the rocks examined, the relative abundance of primary minerals is the same in the weathering rind and corresponding unweathered rock. This is true even for olivine, the least stable phase in the rocks studied. Thus, preferential dissolution is not a controlling factor in the observed spectral changes. Microcracks form by expansion and dissolution and represent <20 vol% of the weathering rinds studied. While they potentially act as blackbody cavities, they probably influence emissivity spectra more by acting as sites where secondary phases form. Because the cracks are generally a few micrometers in width, the secondary phases filling them are optically thin, which may produce nonlinearity in spectral mixing of mineral phases, complicating spectral modeling. Secondary phases are Si-Al-rich and strongly influence the Si-O stretching region of infrared spectra. Dissolution of silica from primary phases and its precipitation in microcracks are the principle factors controlling changes in emissivity spectra in weathered rocks. These changes can lead to inaccurate relative abundances of primary phases derived from deconvolution modeling of weathered rocks. Also, the secondary silicates are generally amorphous to poorly crystalline, and deconvolution modeling misinterprets these materials as silicate glasses and clay minerals. The exact effects weathering exerts on emissivity spectra and subsequent modeling results will depend on what secondary silicates form, particularly how much silica is present, which will in turn depend on the conditions of weathering. However, the basic scenario of crack formation and mineralogical redistribution of silica should hold for a wide range of weathering conditions, and similar effects are expected for weathered Martian surfaces.

Kraft, M. D.; Michalski, J. R.; Sharp, T. G.

2005-12-01

26

The weathering of municipal solid waste incineration bottom ash evaluated by some weathering indices for natural rock.  

PubMed

The weathering of municipal solid waste incineration (MSWI) residues consists of complicated phenomena. This makes it difficult to describe leaching behaviors of major and trace elements in fresh/weathered MSWI bottom ash, which was relevant interactively to pH neutralization and formation of secondary minerals. In this study, mineralogical weathering indices for natural rock profiles were applied to fresh/landfilled MSWI bottom ash to investigate the relation of these weathering indices to landfill time and leaching concentrations of component elements. Tested mineralogical weathering indices were Weathering Potential Index (WPI), Ruxton ratio (R), Weathering Index of Parker (WIP), Vogt's Residual Index (V), Chemical Index of Alternation (CIA), Chemical Index of Weathering (CIW), Plagioclase Index of Alternation (PIA), Silica-Titania Index (STI), Weathering Index of Miura (Wm), and Weatherability index of Hodder (Ks). Welch's t-test accepted at 0.2% of significance level that all weathering indices could distinguish fresh and landfilled MSWI bottom ash. However, R and STI showed contrasted results for landfilled bottom ash to theoretical expectation. WPI, WIP, Wm, and Ks had good linearity with reclamation time of landfilled MSWI bottom ash. Therefore, these four indices might be applicable as an indicator to identify fresh/weathered MSWI bottom ash and to estimate weathering time. Although WPI had weak correlation with leachate pH, other weathering indices had no significant correlation. In addition, all weathering indices could not explain leaching concentration of Al, Ca, Cu, and Zn quantitatively. Large difficulty to modify weathering indices correctly suggests that geochemical simulation including surface sorption, complexation with DOM, and other mechanisms seems to be the only way to describe leaching behaviors of major and trace elements in fresh/weathered MSWI bottom ash. PMID:22796015

Takahashi, Fumitake; Shimaoka, Takayuki

2012-07-12

27

Sandstone weathering processes damaging prehistoric rock paintings at the Albarracin Cultural Park, NE Spain  

NASA Astrophysics Data System (ADS)

The rock paintings in cliff-foot caves of the Albarracin Cultural Park are known as some of the most important evidences of the Levantine prehistoric art of Spain (8000 3000 BP). The paintings are on sandstone (Buntsandstein facies) of Triasic age, which may develop intense weathering. The analysis of the variables controlling the weathering indicate that salt and wetting-drying weathering are responsible for granular disintegration and flaking, which lead to rock painting deterioration.

Benito, G.; Machado, M. J.; Sancho, C.

1993-09-01

28

Plant-induced weathering of a basaltic rock: experimental evidence  

NASA Astrophysics Data System (ADS)

The active role of higher plants in the weathering of silicate minerals and rocks is still a question for debate. The present work aimed at providing experimental evidence of the important role of a range of crop plants in such processes. In order to quantitatively assess the possible effect of these diverse plant species on the weathering of a basaltic rock, two laboratory experiments were carried out at room temperature. These compared the amounts of elements released from basalt when leached with a dilute salt solution in the presence or absence of crop plants grown for up to 36 days. For Si, Ca, Mg, and Na, plants resulted in an increase in the release rate by a factor ranging from 1 to 5 in most cases. Ca and Na seemed to be preferentially released relative to other elements, suggesting that plagioclase dissolved faster than the other constituents of the studied basalt. Negligible amounts of Fe were released in the absence of plants as a consequence of the neutral pH and atmospheric pO 2 that were maintained in the leaching solution. However, the amounts of Fe released from basalt in the presence of plants were up to 100- to 500-fold larger than in the absence of plants, for banana and maize. The kinetics of dissolution of basalt in the absence of plants showed a constantly decreasing release rate over the whole duration of the experiment (36 days). No steady state value was reached both in the absence and presence of banana plants. However, in the latter case, the rates remained at a high initial level over a longer period of time (up to 15 days) before starting to decrease. For Fe, the maximum rate of release was reached beyond 4 days and this rate remained high up to 22 days of growth of banana. The possible mechanisms responsible for this enhanced release of elements from basalt in the presence of plants are discussed. Although these mechanisms need to be elucidated, the present results clearly show that higher plants can considerably affect the kinetics of dissolution of basalt rock. Therefore, they need to be taken into account when assessing the biogeochemical cycles of elements that are major nutrients for plants, such as Ca, Mg, and K, but also micronutrients such as Fe and 'nonessential' elements such as Si and Na.

Hinsinger, Philippe; Fernandes Barros, Omar Neto; Benedetti, Marc F.; Noack, Yves; Callot, Gabriel

2001-01-01

29

Fractionation of Cu, Fe, and Zn isotopes during the oxidative weathering of sulfide-rich rocks  

Microsoft Academic Search

We measured the Fe, Cu, and Zn isotopic compositions of the fluids generated during leaching experiments with pyrite-, chalcopyrite-, and sphalerite-rich rocks and with a sphalerite mineral separate. Our study demonstrates that the oxidative weathering of sulfide-rich rocks can produce substantial variations in Fe (?1.75 to +1.0‰ ?56Fesolution-pyrite rock) and Cu (0.0 to +2.0‰ ?65Cusolution-chalcopyrite rock) isotopes and small variations

Alvaro Fernandez; David M. Borrok

2009-01-01

30

Long-wave infrared hyperspectral imagery of weathering trajectories on Hawaiian basaltic rock  

Microsoft Academic Search

A long wave infrared (LWIR) hyperspectral imager, the University of Hawaii's Airborne Hyperspectral Imager (AHI), was used to relate systematic changes in LWIR spectral features to weathering trajectories on the surfaces of basaltic rocks. Kahle and others proposed that in relation to the LWIR spectra, that devitrification of chilled glassy margins dominate the first stages of weathering, followed by the

Orion Carlisle; Paul G. Lucey; Sarah B. Sherman

2005-01-01

31

Geoelectric investigations into sandstone moisture regimes: Implications for rock weathering and the deterioration of San Rock Art in the Golden Gate Reserve, South Africa  

Microsoft Academic Search

The Clarens sandstone in the Golden Gate Reserve, South Africa, is the canvas for a collection of San (Bushmen) Rock Art, dating from Neolithic times until as recently as 150years ago. This Rock Art is under threat from human interference but also, to a greater degree, from weathering processes on the rock surface. The dominant weathering processes occurring in the

L. Mol; H. A. Viles

2010-01-01

32

Evaluation of rock mechanical behaviors under uniaxial compression with reference to assessed weathering grades  

Microsoft Academic Search

Summary  A weathering classification for granitic rock materials from southeastern Brazil was framed based on core characteristics.\\u000a The classification was substantiated by a detailed petrographic study. Indirect assessment of weathering grades by density,\\u000a ultrasonic and Schmidt hammer index tests was performed. Rebound values due to Schmidt hammer multiple impacts at one representative\\u000a point were more efficient in predicting weathering grades than

A. Basu; T. B. Celestino; A. A. Bortolucci

2009-01-01

33

Weather  

NSDL National Science Digital Library

This project will help you understand the weather and investigate weather interactively. What are the components of weather? How do you measure weather? Investigate the WeatherScholastic: Weather WatchWeatherWeather Center for Our 4th Grade ...

Lai, Ms.

2007-02-08

34

The relationship between geomechanical properties and weathering indices of granitic rocks, Hamedan, Iran  

Microsoft Academic Search

In order to assess the relationships between geomechanical properties of weathered granitic rocks, physical and mechanical analysis were performed on tonalite, hololeucogranite and porphiroid monzogranite of the Hamedan area of the west Iran. The purpose of this study is to apply correlation analysis to investigate the relationships between petrographical, physical and mechanical properties of granitic rocks. The results suggest that

M. Heidari; G. R. Khanlari; A. A. Momeni; H. Jafargholizadeh

2011-01-01

35

The role of rock weathering in the phosphorus budget of terrestrial watersheds  

Microsoft Academic Search

Residual soils (saprolites) developed on crystalline rocks appear to form by an essentially isovolumetric process (i.e. without dilation or compaction). Isovolumetric geochemical analysis of a suite of saprolite samples developed on a common parent rock can be used to estimate the relative rates of long-term losses of P and Si during weathering. Using the export of dissolved Si in rivers

Leonard Robert Gardner

1990-01-01

36

Cracks in desert pavement rocks: Further insights into mechanical weathering by directional insolation  

Microsoft Academic Search

The formation of cracks is a fundamental first step in the physical weathering of rocks in desert environments. In this study we combine new field data from the Mojave (U.S.), Gobi (Mongolia) and Strzelecki (Australia) deserts that collectively support the hypothesis that meridional cracks (cracks with orientations not readily attributable to rock anisotropies or shape) in boulders or cobbles form

Martha Cary Eppes; Leslie D. McFadden; Karl W. Wegmann; Louis A. Scuderi

2010-01-01

37

Uranium thorium chronometry of weathering rinds: Rock alteration rate and paleo-isotopic record of weathering fluids  

NASA Astrophysics Data System (ADS)

The potential of 238U- 234U- 230Th chronometry for constraining the formation rate of weathering rinds developed on fresh rocks is assessed by analyzing a weathering rind on a basaltic clast from a 125 kyr old Costa Rican alluvial terrace. Eighteen subsamples were collected from one section of the clast by drilling cores (4 mm in diameter and 5 mm depth) along two transects straddling the core-rind boundary. Variations of major and trace element concentrations along the two transects point out (a) intense loss of alkaline and alkaline-earth elements, (b) conservative behaviour of elements such as Zr, Hf and Th, and (c) external input of U into the rind without any evidence of U loss during basalt weathering. In addition, variations in U concentrations along the transects show that the main U-Th fractionation process associated with the weathering of the basaltic clast is an external input of U (without addition nor loss of Th) in the basalt rind transition zone, and that, once deposited U is immobile in the weathering rind. In the frame of this interpretation scheme, a weathering rate of 0.5 ± 0.2 mm/kyr can be calculated for the studied clast, which is consistent with geological and isotopic evidence constraining the depositional ages of the terraces. In addition, the variations in the ( 234U/ 238U) ratio along the analysed transects as well as the increase in Sr isotopic ratios within the weathering rind are best explained by temporal variation of the U activity ratios and Sr isotope ratios of the soil solutions brought into the rind. This work highlights how well detailed U-Th chronological studies of weathering rinds can (1) constrain the formation rates of weathering systems, and (2) record the time variation of isotopic composition of weathering fluids.

Pelt, E.; Chabaux, F.; Innocent, C.; Navarre-Sitchler, A. K.; Sak, P. B.; Brantley, S. L.

2008-11-01

38

[Role of microscopic fungi in the process of weathering of pegmatite deposit rocks and minerals].  

PubMed

The object of this work was to study the effect of microscopic fungi isolated from the weathering zone of a pegmatite deposit on the transport of elements and the degradation of rocks and minerals. Regardless of the chemical composition of rocks and minerals, microscopic fungi accelerated the leaching of elements as compared to the purely chemical process. The extraction of Li, Si, Al and Fe under the action of microorganisms increased by factors of 1.4-1.7, 2.7-4.0, 5.0-8.7 and 4-18, respectively. In the case of chemical weathering, the extraction of elements occurred at a high rate only at the beginning; then the process either decelerated or stopped. The mechanism of action of microscopic fungi on rocks and minerals is discussed as well as the role of these microorganisms in the weathering of spodumene and the surrounding rocks, pegmatites an shales, which occurs in the zone of hypergenesis. PMID:7194415

Avakian, Z A; Karavaiko, G I; Mel'nikova, E O; Krutsko, V S; Ostroushko, Iu I

39

Changes in the weathering of rock surfaces in different geomorphological environments: glacial, nival and coastal.  

NASA Astrophysics Data System (ADS)

The sclerometer or Schmidt Rock Test Hammer has been broadly applied in geomorphology to estimate the strength of different rock types and to measure the degree of rock weathering. It has been proved that for a rock type, the rebound values are lower in weathered than in fresh rock surfaces. This evidence suggests that if there is any factor that causes a gradual change in the weathering degree, it must be possible to identify a distinctive tendency with the sclerometer. There are two types of factors that can cause gradual changes in the weathering degree. First, those related with the time of exposure of a rock surface, which are the basis of works that attempt to use the sclerometer as a tool for relative chronology. Second, those related with the frequency or duration at which the weathering agents operate, which are the basis for the studies focused on the efficacy of weathering. In both cases it is essential to understand how the factors of weathering are spatially distributed in order to achieve a good sampling procedure. We applied the sclerometer in three different environments: rock coasts, glacially exposed surfaces and rock surfaces subjected to nival processes. The sclerometer was used in a receding glacier in Tierra de Fuego, Argentina, assuming that the rock surface must be more weathered as more time passed since the exposure. The hypothesis was confirmed by the negative correlation between rebound values and the distance to the glaciar front. In rocky coasts, it was proved by field and laboratory data that one of the main factors responsible for variations in rock strength is the degree of weathering by tidally-induced wetting and drying. We found negative correlations between rebound values and tidal elevation in very different coastal environments in the NW of Spain and in the Beagle Channel. We also found that the absence of this relationship may be caused by processes of mechanical erosion, but they also can respond to disequilibrium of the intertidal surfaces with tidal range. The research on nival processes was conducted in an ancient glacial cirque in the western mountains of Galicia (NW Spain). The hypothesis here was that weathering degree of rock surface is related with the abrasion produced when a late-lying snow cover slides in the spring. The frequency and extent to which abrasion and other erosional processes take place depends mainly on the thickness of the snow accumulated in a rock wall. Therefore, the rock surfaces are more weathered as frequency and intensity of abrasion decreases with the distance to the rock wall. The experience in three different types of environment suggests that when the sclerometer is used to measure the weathering degree, the sampling method arises as one of the most important factors. The distribution of the sampling points must respond to the characteristics of each area, which needs a previous understanding of the processes and factors responsible of the variations in the degree of weathering. Aknowledgements This work was supported by the research projects GL2004-3380/BOS (Ministerio de Educación y Ciencia) and PGIDIT06PXIB239226PR and PGDIT05PXIC21001PN (Xunta de Galicia). A. Feal Pérez is supported by the grant AP2006-03854

Feal-Pérez, A.; Blanco-Chao, R.; Pérez-Alberti, A.; López-Bedoya, J.; Valcárcel-Díaz, M.

2009-04-01

40

Porosity and surface area evolution during weathering of two igneous rocks  

SciTech Connect

During weathering, rocks release nutrients and storewater vital for growth ofmicrobial and plant life. Thus, the growth of porosity as weathering advances into bedrock is a life-sustaining process for terrestrial ecosystems. Here, we use small-angle and ultra small-angle neutron scattering to show how porosity develops during initial weathering under tropical conditions of two igneous rock compositions, basaltic andesite and quartz diorite. The quartz diorite weathers spheroidally while the basaltic andesite does not. The weathering advance rates of the two systems also differ, perhaps due to this difference in mechanism, from 0.24 to 100 mm kyr1, respectively. The scattering data document how surfaces inside the feldspar-dominated rocks change as weathering advances into the protolith. In the unaltered rocks, neutrons scatter fromtwo types of featureswhose dimensions vary from6 nmto 40 lm: pores and bumps on pore grain surfaces. These features result in scattering data for both unaltered rocks that document multi-fractal behavior: scattering is best described by amass fractal dimension (Dm) and a surface fractal dimension (Ds) for features of length scales greater than and less than 1 lm, respectively. In the basaltic andesite, Dm is approximately 2.9 and Ds is approximately 2.7. The mechanism of solute transport during weathering of this rock is diffusion. Porosity and surface area increase from 1.5%to 8.5%and 3 to 23 m2 g1 respectively in a relatively consistent trend across themm-thick plagioclase reaction front. Across this front, both fractal dimensions decrease, consistentwith development of amoremonodisperse pore networkwith smoother pore surfaces. Both changes are consistent largely with increasing connectivity of pores without significant surface roughening, as expected for transport-limited weathering. In contrast, porosity and surface area increase from 1.3% to 9.5% and 1.5 to 13 m2 g1 respectively across a many cm-thick reaction front in the spheroidally weathering quartz diorite. In that rock, Dm is approximately 2.8 andDs is approximately 2.5 prior to weathering. These two fractals transform during weathering to multiple surface fractals as micro-cracking reduces the size of diffusion-limited subzones of thematrix.Across the reaction front of plagioclase in the quartz diorite, the specific surface area and porosity change very little until the pointwhere the rock disaggregates into saprolite. The different patterns in porosity development of the two rocks are attributed to advective infiltration plus diffusion in the rock that spheroidally fractures versus diffusion-only in the rock that does not. Fracturing apparently diminishes the size of the diffusion-limited parts of the spheroidally weathering rock system to promote infiltration of meteoric fluids, thereforeexplaining the faster weathering advance rate into that rock.

Navarre-Sitchler, Alexis [Colorado School of Mines, Golden; Cole, David [Ohio State University; Rother, Gernot [ORNL; Jin, Lixin [University of Texas, El Paso; Buss, Heather [University of Bristol, UK; Brantley, S. L. [Pennsylvania State University, University Park, PA

2013-01-01

41

[Enrichment and release of uranium during weathering of sedimentary rocks in Wujiang catchments].  

PubMed

Thirteen weathering profiles of typical rocks such as limestone, dolomitic limestone, dolomite, sillcalite, black shale and purple sandrock from Wujiang catchments were selected for discussing enrichment and release behavior of uranium (U) during rock weathering, and studying its impact on riverine U distribution in the catchments during weathering of these rocks with methods of correlation analysis and mass balance calculation. The purpose of this study is to improve our understanding on biogechemical cycling of U and set a basis for catchment protection against U pollution. The results show that the enrichment extent of U in soils from the Wujiang catchments is usually higher than that of upper continental crust (UCC), China soil (CS) and world soil (WS). The ability of enrichment and release of U is partly controlled by content of U in bedrocks, contents and adsorption ability of clay minerals and Fe-oxides/hydroxides in weathering profiles. Our study also reveals that release of U mainly from weathering of limestone and partly from weathering of dolomite and clastic rocks exerts an important control on riverine U distribution. PMID:17326439

Song, Zhao-Liang; Liu, Cong-Qiang; Han, Gui-Lin; Wang, Zhong-Liang; Yang, Cheng; Liu, Zhan-Min

2006-11-01

42

Weathering and its relation to geomechanical properties of Cavusbasi granitic rocks in northwestern Turkey  

Microsoft Academic Search

.   The effect of mainly mechanical weathering on the granodiorites, granites and quartz diorites of the Cavusbasi area of northwest\\u000a Turkey are described, the samples having been taken from cores and field exposures. The primary characteristics of these rocks\\u000a are affected by the weathering process which results in a significant constraint on their use in engineering works. The tests\\u000a undertaken

E. Arel; A. Tugrul

2001-01-01

43

Weathering Of Plutonic Rocks: A Case Study From Calabria, Southern Italy  

NASA Astrophysics Data System (ADS)

The effect of chemical and mechanical weathering on the mineralogy and microfabric of Paleozoic tonalite of the Serre massif, in southern Calabria, has been recognised from the analysis of samples have been taken from cores and field exposure. The original rock contains euhedral zoned plagioclase (andesine-oligoclase), ortoclase, anhedral patches of quartz, green hornblende and biotite, and opaques, apatite and sphene as accessory minerals. Complete weathering profiles of the Serre tonalite are often up to 30 m deep. Petrography of buried and exposed lithology indicates that the transition from the parent rock to saprolite is consistent with the process of grussification and arenisation, similar to granitoid rock weathering in northern Calabria, and it is marked by both chemical alteration and granular disintegration. The mineralogical changes identified suggest in situ weathering was selective with biotite, plagioclase feldspar and their secondary deuteric products altering before K-feldspar and quartz. Quartz crystals are affected by microcracks showing some fissures. Biotite in various degrees of chloritization, or replaced by iron oxides, along cleavage planes, has been observed. Feldspars have an opaque appearance, due to a microcrystalline secondary product, that is probably an aggregate of clayey mineral replacement during weathering. Evidence of chemical dissolution (etch pits) on plagioclase has been identified. Green hornblende alters to ferruginous products growing as linings along mineral cleavage. The loss of the original structure of the rock and the progress of weathering have been characterised through calculation of the Decomposition Index (X_d), indicating the extent to which the rock microfabric and composition are affected by weathering, leading to soil formation. X_d values in the tonalite from the Serre massif range from 0.1 to 0.75, with increasing decomposition. X_d<0.5 samples exceed those having X_d>0.5. These two microfabric types can be described as granular-framework microfabric (X_d <0.5), related to an initial stage of weathering, mainly involving granular disintegration, and as clay-matrix microfabric (X_d >0.5), due to a later stage of rock decay during which chemical decomposition prevails. The contemporaneous presence of both granular- and clay-matrix microfabric reflects a complex weathering profile development, and emphasises the need to sample the weathering profile very carefully before making general statements on the factors influencing weathering. Also, these microfabrics are a useful tool to discriminate between weathering stages; nonetheless the saprolite microfabrics are useful to gain a better understanding of the processes that control landscape evolution in highly weathered rocks. Furthermore, the occurrence of gravelly and sandy regolith at Serre massif exposed surface indicates that the process of grussification is not solely restricted to deep weathering environment but can be achieved by the high current leaching factor to which the profiles are subjected. Thus we suggest that the rock weathering and the production of coarse loose debris are still active and continuous under present-day climatic conditions.

Le Pera, E.; Viola, S.; Ietto, F.

2003-04-01

44

Complex weathering in drylands: Implications of ‘stress’ history for rock debris breakdown and sediment release  

NASA Astrophysics Data System (ADS)

Weathering studies have often sought to explain features in terms of a prevailing set of environmental conditions. However, it is clear that in most present-day hot desert regions, the surface rock debris has been exposed to a range of weathering environments and processes. These different weathering conditions can arise in two ways, either from the effects of long-term climate change acting on debris that remains relatively static within the landscape or through the spatial relocation of debris from high to low altitude. Consequently, each fragment of rock may contain a unique weathering-related legacy of damage and alteration — a legacy that may greatly influence its response to present-day weathering activity. Experiments are described in which blocks of limestone, sandstone, granite and basalt are given ‘stress histories’ by subjecting them to varying numbers of heating and freezing cycles as a form of pre-treatment. These imposed stress histories act as proxies for a weathering history. Some blocks were used in a laboratory salt weathering simulation study while others underwent a 2 year field exposure trial at high, mid and low altitude sites in Death Valley, California. Weight loss and ultrasonic pulse velocity measurements suggest that blocks with stress histories deteriorate more rapidly than unstressed samples of the same rock type exposed to the same environmental conditions. Laboratory data also indicate that the result of imposing a known ‘weathering history’ on samples by pre-stressing them is an increase in the amount of fine sediment released during salt weathering over a given period of time in comparison to unstressed samples.

Warke, P. A.

2007-03-01

45

Identification of rock weathering and environmental control in arid catchments (northern Xinjiang) of Central Asia  

NASA Astrophysics Data System (ADS)

Chemical weathering is an integral part of the earth surface processes, whose spatial patterns and controlling factors on continental scale are still not fully understood. Highlands of the Asian continent have been shown having some of the highest observed rates of chemical weathering yet reported. However, the paucity of river gauge data in many of these terrains has limited determination of chemical weathering budget in a continental scale. A dataset of three large watersheds throughout northern Xinjiang in Central Asia is used to empirically identify chemical weathering regimes and interpret the underlying controlling factors. Detailed analysis of major ion ratios and a forward model of mass budget procedure are presented to distinguish the relative significances and contributions of silicate, carbonate weathering and evaporite dissolution. The analytical results show that carbonic acid is the most important weathering agent to the studied watersheds. Silicate weathering contributes, on average, ˜17.8% (molar basis) of total cations on a basin wide scale with an order of Zhungarer > Erlqis > Yili, indicating that silicate weathering, however, does not seem to be intense in the study basins. Evaporite dissolution, carbonate weathering and precipitation input contribute 43.6%, 29.7% and 8.9% of the total dissolved cations on average for the whole catchment, respectively. The three main morphological and hydrological units are reflected in water chemistry. Rivers from the montane areas (recharge area) of the three watersheds are very dilute, dominated by carbonate and silicate weathering, whereas the rivers of piedmont areas as well as the rivers of the sedimentary platform (runoff area) are dominated by carbonate weathering, and rivers of desert plain in the central Zhungarer basin (discharge area) are dominated by evaporite dissolution and are SO4 rich. This spatial pattern indicates that, beside lithology, runoff conditions have significant role on the regional chemical weathering regimes. Chemical weathering processes in the areas appear to be significantly climate controlled, displaying a tight correlation with runoff and aridity. Carbonate weathering are mostly influenced by runoff, which is higher in the mountainous part of the studied basins. The identification of chemical weathering regimes from our study confirmed the weathering potential and complexity of temperate watersheds in arid environment and that additional studies of these terrains are warranted. However, because the dominant weathering reactions in the sedimentary platform of northern Xinjiang are of carbonates and evaporites rather than silicate minerals, and the climatic factors have important role on the rock weathering regimes, we think that weathering at the arid temperate drainage system (Central Asia) is maybe not an important long-term sink for atmospheric CO2, if the future climate has no great change.

Zhu, Bingqi; Yu, Jingjie; Qin, Xiaoguang; Rioual, Patrick; Zhang, Yichi; Liu, Ziting; Mu, Yan; Li, Hongwei; Ren, Xiaozong; Xiong, Heigang

2013-04-01

46

Uranium and thorium in weathering and pedogenetic profiles developed on granitic rocks from NW Spain  

Microsoft Academic Search

Uranium and thorium were analyzed in seven weathering and pedogenetic soil profiles developed on granitic rocks from NW Spain. Concentrations were measured by X-ray fluorescence spectrometry (XRF) and the U- and Th-bearing minerals were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Both elements were determined in rock, bulk soil and in different grain-size fractions (sand:

Teresa Taboada; Antonio Martínez Cortizas; Carlota García; Eduardo García-Rodeja

2006-01-01

47

Biomineralization of Weathered Rock Rinds: Examples from the Lower Afroalpine Zone on Mount Kenya  

Microsoft Academic Search

Rock rinds have been used for half a century to date glacial deposits and recently inroads have been developed to use nuclides to provide absolute ages of weathering rinds in pebble clasts. While maximum and minimum rind thicknesses have helped to elucidate time since deposition and allowed stratigraphic division of deposits at glacial rank, little has been done to investigate

W. C. Mahaney; D. H. Krinsley; C. C. R. Allen

2012-01-01

48

Field and laboratory tests on risk of slope failure due to weathering of rock materials  

NASA Astrophysics Data System (ADS)

Authors set out the challenge to explore the mechanism of rock weathering and its effects to the geotechnical hazards. Any natural or human induced disturbances to the natural slopes speed up their weathering process. So, exploration of both disturbed and undisturbed slopes is necessary for robust understanding. Various regions in Asia were explored to experience variety of environmental and climatic conditions. Field exploration on the thickness and in-situ mechanical property was carried out by performing seismic refraction surveys, dynamic cone penetration tests and Schmidt hammer tests at various sites in Japan and Pakistan. In laboratory change in mechanical property of soft rocks due to weathering has been observed and slake durability tests were conducted on various rocks. Field exploration indicated that the thickness of weathered layer is 1 meter or its roundabouts and having S-wave velocity of 200-300 m/s. Laboratory testing differentiated the slaking potential and mechanical property degradation of various rocks. Moreover sensible correlations had been observed in thickness calculated by seismic refraction or dynamic cone penetration in field. Slake durability index showed good correlation with Schmidt hammer hardness and mechanical property. A general agreement was also observed when strength and S-wave velocities from laboratory tests were compared with the field exploration. Authors believed that the study provides the useful information on the long term prediction and assessment of landslide risk.

Qureshi, M. U.; Towhata, I.; Yamada, S.; Aziz, M.

2009-04-01

49

Weathering Of Plutonic Rocks: A Case Study From Calabria, Southern Italy  

Microsoft Academic Search

The effect of chemical and mechanical weathering on the mineralogy and microfabric of Paleozoic tonalite of the Serre massif, in southern Calabria, has been recognised from the analysis of samples have been taken from cores and field exposure. The original rock contains euhedral zoned plagioclase (andesine-oligoclase), ortoclase, anhedral patches of quartz, green hornblende and biotite, and opaques, apatite and sphene

E. Le Pera; S. Viola; F. Ietto

2003-01-01

50

A tectono-geomorphic model of the hydrogeology of deeply weathered crystalline rock: Evidence from Uganda  

NASA Astrophysics Data System (ADS)

Deeply weathered crystalline rock forms important aquifers for public water supply throughout low-latitude regions of Africa, South America, and Asia, but these aquifers have considerable heterogeneity and produce low well yields. Aquifers occur in the bedrock and overlying weathered mantle and are the products of geomorphic activity of meteoric water, principally deep weathering and stripping. The fundamental relationship between the hydrogeology and geomorphology of these terrains has, however, remained unresolved. This study demonstrates the ability of a recently developed tectono-geomorphic model of landscape evolution in Uganda to explain the hydrogeological characteristics of two basins, as determined using a combination of textural analysis, slug tests, packer tests, and pumping tests. The geopetal imprint of long-term deep weathering and erosional unloading is identified in the vertical heterogeneity of the fractured-bedrock and weathered-mantle aquifers; horizontal heterogeneity is lithologically controlled. The two units form an integrated aquifer system in which the more transmissive (5-20 m2/d) and porous weathered mantle provides storage to underlying bedrock fractures (transmissivity, T, ?1 m2/d). The thickness and extent of the more productive weathered-mantle aquifer are functions of contemporary geomorphic processes. The utility of the tectono-geomorphic model, applicable to deeply weathered environments, is that it coherently describes the basin-scale hydrogeological characteristics of these complex terrains.

Taylor, Richard; Howard, Ken

2000-06-01

51

Salinity and chemical weathering rate of rocks in a semi-arid region  

NASA Astrophysics Data System (ADS)

Rain and river water samples were collected during one year in the Salgado River Basin, a semiarid region in Bahia State, Brazil. The Na, Ca, and K and Mg concentrations and U and total dissolved salts contents in river water, rocks and soils of the basin were measured. A geochemical balance and the chemical weathering of rocks was determined. The water of Salgado River shows high concentration of the total dissolved salts (1,42 g/l) making it impossible to determine the chemical weathering rate of rocks by using the major catons as tracer elements. The results of 36 t/sq km-yr was obtained by using uranium as natural tracer.

Nordemann, L. M. M.

1983-02-01

52

Microstructural weathering of sedimentary rocks by freeze–thaw cycles: Experimental study of state and transfer parameters  

Microsoft Academic Search

The frost sensitivity of a rock is resulting from the combined action of processes linked to porous network characteristics (state parameters) and to the way water flows into this porous network (transfer parameters), our study was thus about the influence of these parameters on frost weathering of rocks. Sedimentary rocks often found on buildings (limestone and sandstone) and consequently submitted

Alice Saad; Sylvine Guédon; François Martineau

2010-01-01

53

Rocks  

NSDL National Science Digital Library

This guide explores rocks, from processes that can change them (such as weathering), to what can happen to them as they move through the rock cycle. Using this guide, teachers of middle school students will focus on the tangible process of sedimentary roc

National Science Teachers Association (NSTA)

2009-07-01

54

Weather  

NSDL National Science Digital Library

Learn all about the aspects of weather that effect us every day. Click here to see a weather forecast for anywhere in the world World Wide Weather Watch See what happens to weather when you change conditions at your house Weather Maker Weather Games ...

Hyde, Mrs.

2007-02-08

55

Weather  

NSDL National Science Digital Library

This lesson is written for fourth grade students. Students will explore weather and the effects it has on their lives. What is weather? video of what is weather Let's take a walk through the weather. Put on your hats and coats! Clouds Cloud Types Clouds - Dan's Wild Weather Page What to Wear? What to Wear? What to Drink? Weather Patterns and Climatic Regions ...

Bullough, Ms.

2010-06-24

56

Weather  

NSDL National Science Digital Library

This is a first grade weather unit. SEASONS Fall Winter Build a Snowman Spring Summer What things determine and effect the weather? Cloud Precipitation Sunshine Temperature Visibility Wind Direction Wind Force WEATHER VIDEOS Tornado Hurricane Hail Lightning FUN AND GAMES Dress the Bear for the Weather The Great Weather Race Game Weather coloring books for kids ...

Stearns, Ms.

2008-10-25

57

Weather  

NSDL National Science Digital Library

Have you ever wondered how the weather man, or meteorolgist, on TV knows what to say about tomorrow\\'s weather? It\\'s because they have certain tools that they use that help them predict what the weather will be. Throughout this school year you are going to be making tools and predicting weather just like a meterorologist! Task You are going to be weather forcasters! You are going to record and track weather patterns throughout the year. You will also use weather tools to make predictions about the weather like real weather forecasters! The Process 1. First we need to learn a little bit about weather so ...

Williams, Ms.

2005-10-25

58

Storage and release of fossil organic carbon related to weathering of sedimentary rocks  

NASA Astrophysics Data System (ADS)

The biogeochemical carbon cycle, which plays an undeniable role in global climate change, is defined both by the size of carbon reservoirs (such as the atmosphere, biomass, soil and bedrock) and the exchange between them of various mineral and organic carbon forms. Among these carbon forms, fossil organic carbon (FOC) (i.e., the ancient organic matter stored in sedimentary rocks) is widely observed in modern environments but is not included in the supergene carbon budget. Using a digitized map of the world and an existing model of CO 2 consumption associated with rock weathering, we establish the global distribution of FOC stored in the first meter of sedimentary rocks and a first estimation of annual FOC delivery to the modern environment resulting from chemical weathering of these rocks. Results are given for the world's 40 major river basins and extended to the entire continental surface. With a mean value of 1100 10 9 t, mainly controlled by shale distribution, the global FOC stock is significant and comparable to that of soil organic carbon (1500 10 9 t). The annual chemical delivery of FOC, estimated at 43 10 6 t yr - 1 and controlled by the areal distribution of shales and runoff, is of the same order of magnitude as the FOC output flux to oceans. Chemical weathering of bedrock within the Amazon basin produces one-quarter of the total global flux of FOC derived from chemical weathering, and thus is expected to govern FOC release on a global scale. These results raise important questions concerning the role of FOC in the modern carbon cycle as well as the origin and the budget of carbon in soils and rivers.

Copard, Yoann; Amiotte-Suchet, Philippe; Di-Giovanni, Christian

2007-06-01

59

Metasomatic mechanism of weathering-pedogenesis of carbonate rocks: I. Mineralogical and micro-textural evidence  

Microsoft Academic Search

On the basis of mineralogical, geochemical and micro-textural studies of the typical sections of the red weathering crust\\u000a of carbonate rocks in the subtropical karst areas of Guizhou Province and Guangxi Autonomous Region, we have found, either\\u000a on a microscopic or on a macroscopical scale and in different positions of the sections, the most direct and most important\\u000a mineralogical and

Zhu Lijun; Li Jingyang

2002-01-01

60

High-frequency rock temperature data from hyper-arid desert environments in the Atacama and the Antarctic Dry Valleys and implications for rock weathering  

Microsoft Academic Search

In desert environments with low water and salt contents, rapid thermal variations may be an important source of rock weathering. We have obtained temperature measurements of the surface of rocks in hyper-arid hot and cold desert environments at a rate of 1\\/s over several days. The values of temperature change over 1-second intervals were similar in hot and cold deserts

Christopher P. McKay; Jamie L. Molaro; Margarita M. Marinova

2009-01-01

61

Geochemical evolution of solutions derived from experimental weathering of sulfide-bearing rocks  

USGS Publications Warehouse

The chemical composition of natural waters is affected by the weathering of geologic materials at or near the surface of the Earth. Laboratory weathering experiments of whole-rock sulfide rocks from the Shoe-Basin Mine (SBM) and the Pennsylvania Mine (PM) from the Peru Creek Basin, Summit County, Colorado, indicate that the mineral composition of the sulfide rocks, changes in pH, the duration of the experiment, and the formation of sorbents such as Fe and Al oxyhydroxides affect the chemical composition of the resulting solution. Carbonate minerals in the rock from SBM provide buffering capacity to the solution, contribute to increases in the pH and enhance the formation of Fe and Al oxyhydroxides, which sorb cations from solution. The final solution pH obtained in the experiments was similar to those measured in the field (i.e., 2.8 for PM and 5.0 for SBM). At PM, acidic, metal-rich mine effluent is discharged into Peru Creek where it mixes with stream water. As a result, the pH of the effluent increases causing Fe and Al oxyhydroxide and schwertmannite to precipitate. The resulting solids sorb metal cations from the water thereby improving the quality of the water in Peru Creek. ?? 2006.

Munk, L.; Faure, G.; Koski, R.

2006-01-01

62

Terrestrial laser scanning and exploratory spatial data analysis for the mapping of weathering forms on rock art panels  

Microsoft Academic Search

Rock art conservators are faced with complex decisions to prioritize rock art panels for protection from destructive forces of weathering. We provide a system to facilitate such decision making that blends traditional remote sensing with interactive techniques of exploratory spatial data analysis. Our system, ‘mapping weathering forms in three-dimensional (3D)’ (MapWeF) uses a 3D laser scanning device for sub-centimetre data

B. J. Vogt; R. M. Edsall

2010-01-01

63

Weather  

NSDL National Science Digital Library

Meteorologists study the weather by recording and analyzing data. You can become an amateur meteorologist by building your own weather station and keeping a record of your measurements. After a while, you\\'ll notice the weather patterns that allow meteorologists to forecast the weather. Tasks: 1. As a group you will build a weather station outside. 2. Your group will build instruments to measure the weather. 3. Each person will record the data in personal weather journals. Process: 1.Since weather happens outside, you\\'ll need to make ...

Tuttle, Rachelle

2005-10-25

64

Change of black shale organic material surface area during oxidative weathering: Implications for rock-water surface evolution  

NASA Astrophysics Data System (ADS)

Black shale oxidative weathering plays a significant role in a variety of processes including acid mine drainage and atmospheric CO 2 control. The modeling of weathering is highly dependent on reactive surface area. In this study it is shown that black shale oxidative weathering is regulated mainly by the external, geometrical surface area of rock polyhedrons and the organic matter's (OM) internal surface area. The internal rock surface area decreases dramatically during OM dissolution from ˜15 m 2/g to ˜5 m 2/g. A linear relationship was found between the decrease of internal rock surface area and quantity of OM dissolved. Optical roughness analyses of black and bleached shale surface area reveal the formation of macropores due to the dissolution of mesoporous and probably microporous OM. However, due to deconsolidation, the geometrical external rock polyhedron surface area increases during weathering. Black shale polyhedrons show a doubling of their external surface area as OM decreases. This provokes an increase of the shale volume which is easily accessible by fluids. The increase of the external rock surface area seems to be self-accelerating during weathering. The upscaling of external and internal rock surface area evolution during weathering presented in this study demonstrates the possible application of these results to the improved understanding of a chemical transport in a variety of natural systems.

Fischer, Cornelius; Gaupp, Reinhard

2005-03-01

65

Enrichment and Release of Rare Earth Elements during Weathering of Sedimentary Rocks in Wujiang Catchments, Southwest China  

Microsoft Academic Search

Thirteen weathering profiles of sedimentary rocks such as limestone, dolomitic limestone, dolomite, sillicalite, black shale and purple sandrock from Wujiang catchments were selected for study on enrichment and release behavior of rare earth elements (REE) during weathering, and its impact on plant growth and riverine REE distribution in the catchments with methods of hierachical cluster analysis and mass balance calculation

Zhaoliang Song; Congqiang Liu; Guilin Han; Zhongliang Wang; Zhaozhou Zhu; Cheng Yang

2006-01-01

66

Weather.  

ERIC Educational Resources Information Center

|This theme issue of "The Goldfinch" focuses on weather in Iowa and weather lore. The bulletin contains historical articles, fiction, activities, and maps. The table of contents lists: (1) "Wild Rosie's Map"; (2) "History Mystery"; (3) "Iowa's Weather History"; (4) "Weather Wonders"; (6) "Seasonal Jobs"; (7) "Fiction: Winter Courage"; (8) "Stayin'…

Ruth, Amy, Ed.

1996-01-01

67

Rock albedo and monitoring of thermal conditions in respect of weathering: some expected and some unexpected results  

Microsoft Academic Search

Broadly speaking, there is, at least within geomorphic circles, a general acceptance that rocks with low albedos will warm both faster and to higher temperatures than rocks with high albedos, reflectivity influencing radiative warming. Upon this foundation are built no- tions of weathering in respect of the resulting thermal differences, both at the grain scale and at the scale of

Kevin Hall; B. Staffan Lindgren; Peter Jackson

2005-01-01

68

Mechanical Weathering  

NSDL National Science Digital Library

This activity was designed to give students an opportunity to realize that all rocks weather mechanically and each specific rock type has its own particular rate of weathering. Students discover that mechanical weathering is the process of breaking down bedrock into smaller fragments by physical as opposed to chemical means and that rock weathering, although it seems to occur slowly in human terms, is an extremely significant part of the rock cycle. They will learn that weathered rock materials are called sediments and are the structural basis for soils and can also be compacted into sedimentary rock. Students will realize that rock weathering rates vary widely depending on mineral content, texture, rock type, and climate and that differential weathering (varying weathering rates for two or more rock types in physical contact with each other) has given rise to some of the world's most breathtaking scenery.

69

Uranium and thorium in weathering and pedogenetic profiles developed on granitic rocks from NW Spain.  

PubMed

Uranium and thorium were analyzed in seven weathering and pedogenetic soil profiles developed on granitic rocks from NW Spain. Concentrations were measured by X-ray fluorescence spectrometry (XRF) and the U- and Th-bearing minerals were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS). Both elements were determined in rock, bulk soil and in different grain-size fractions (sand: 2000-50 microm, silt: 50-2 microm, and clay: <2 microm). U concentrations in the rock varied between 5.3 and 27.7 mg kg(-1) and Th concentrations from 5.5 to 50.7 mg kg(-1). The most alkalic rocks can be considered as U-rich granites. Bulk soil U and Th concentrations are similar to those of the rocks (4.8-29.2 and 7.4-56.7 mg kg(-1), respectively), but in the grain-size fractions both elements show the lowest concentrations in the sand and the highest in the clay. In the latter, concentrations are always higher than those of the rocks, particularly in the C horizons with enrichments up to 4 times for U and 5 times for Th. The concentration profiles and the ratios to the parent rock suggest that U and Th are leached from the surface soil and accumulate in the deeper horizons. Mass balance calculations, using Ti as a reference immobile element, also support U and Th leaching in the solum and supergene enrichment in bottom horizons. Leaching seems to be more intense on horizons with gravel content higher than 20%. The leaching of U and Th in the topmost horizons and the accumulation in the bottom soil horizons can be considered as a natural attenuation of the impact of these radiogenic elements in the environment. But their enrichment in the potentially airborne fraction poses some risk of redistribution in the ecosystems. PMID:15923024

Taboada, Teresa; Martínez Cortizas, Antonio; García, Carlota; García-Rodeja, Eduardo

2005-05-31

70

Weather  

NSDL National Science Digital Library

The National Oceanic and Atmospheric Administration (NOAA) provides these two Websites on weather. The first site serves as a major hub for information related to weather, with links to primary data sources, forecasts, maps, images (such as the latest satellite imagery for North America), and a wealth of other data, including space weather. Researchers will also find links to national weather research centers and other related agencies.

71

Chemical weathering of granitic rock: experiments and Pb-Li isotopes tracing  

NASA Astrophysics Data System (ADS)

In a recent study (Négrel et al. 2010, Chem. Geol. Vol. 274) focusing on the lead geochemistry and Pb-isotope ratios of groundwaters along a small (53 km2) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh), we have shown that most of the lead in the groundwaters is of geogenic origin. Combining a weathering model and field observations, we were able to define a two-step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main minerals from the granite in a second step of weathering. In order to go further and to better characterize water/rock interactions, we performed laboratory experiments with the two main granite bedrocks from this site. The aim of the present work is to better constrain the processes of water/rock interactions both in terms of source (dissolution of different primary minerals) and extent of weathering, by measuring Pb isotope signatures in addition with Li isotope signatures. Laboratory experiments consisted in measuring the evolution through time of major and trace elements, as well as Pb and Li isotopic compositions of a rainwater solution in equilibrium with a granite powder. Experiments were carried out at 25°C with a solution/powder mass ratio of 10 considering 15 mL of reference solution TMRAIN-95 and 1.5 g of powdered granite placed in screw-top Teflon° PFA beakers. The beakers were kept in a temperature-controlled oven, which temperature was maintained within 5% of target temperature over the total duration of the experiments. Aliquots of the solution (after filtration at 0.2 ?m) in contact with the granite powder were periodically sampled (from weeks up to 2 years) and analyzed for lead and lithium isotopic compositions. The results show that a radiogenic contribution of lead is observed during the experiments, in agreement with the field observations, and that the light lithium isotope (6Li) is preferentially retained during uptake of Li into secondary minerals. The results of these experiments will be discussed in the frame of the relative proportion of granite weathering (dissolution of primary minerals) to secondary mineral formation.

Millot, R.; Négrel, P.

2011-12-01

72

The effect of temperature on experimental and natural chemical weathering rates of granitoid rocks  

USGS Publications Warehouse

The effects of climatic temperature variations (5-35??C) on chemical weathering are investigated both experimentally using flow-through columns containing fresh and weathered granitoid rocks and for natural granitoid weathering in watersheds based on annual solute discharge. Although experimental Na and Si effluent concentrations are significantly higher in the fresh relative to the weathered granitoids, the proportional increases in concentration with increasing temperature are similar. Si and Na exhibit comparable average apparent activation energies (E(a)) of 56 and 61 kJ/mol, respectively, which are similar to those reported for experimental feldspar dissolution measured over larger temperature ranges. A coupled temperature-precipitation model, using an expanded database for solute discharge fluxes from a global distribution of 86 granitoid watersheds, produces an apparent activation energy for Si (51 kJ/mol), which is also comparable to those derived from the experimental study. This correlation reinforces evidence that temperature does significantly impact natural silicate weathering rates. Effluent K concentrations in the column study are elevated with respect to other cations compared to watershed discharge due to the rapid oxidation/dissolution of biotite. K concentrations are less sensitive to temperature, resulting in a lower average E(a) value (27 kJ/mol) indicative of K loss from lower energy interlayer sites in biotite. At lower temperatures, initial cation release from biotite is significantly faster than cation release from plagioclase. This agrees with reported higher K/Na ratios in cold glacial watersheds relative to warmer temperate environments. Increased release of less radiogenic Sr from plagioclase relative to biotite at increasing temperature produces corresponding decreases in 87Sr/86Sr ratios in the column effluents. A simple mixing calculation using effluent K/Na ratios, Sr concentrations and 87Sr/86Sr ratios for biotite and plagioclase approximates stoichiometric cation ratios from biotite/plagioclase dissolution at warmer temperatures (35??C), but progressively overestimates the relative proportion of biotite with decreasing temperature. Ca, Mg, and Sr concentrations closely correlate, exhibit no consistent trends with temperature, and are controlled by trace amounts of calcite or exchange within weathered biotite. The inability of the watershed model to differentiate a climate signal for such species correlates with the lower temperature dependence observed in the experimental studies.

White, A. F.; Blum, A. E.; Bullen, T. D.; Vivit, D. V.; Schulz, M.; Fitzpatrick, J.

1999-01-01

73

Evidence for Physical Weathering of Iron Meteorite Meridiani Planum (Heat Shield Rock) on Mars  

NASA Astrophysics Data System (ADS)

Meteorites on the surfaces of other solar system bodies can provide natural experiments for monitoring weathering processes. In the case of Mars, clues to the more subtle aspects of water occurrence and reaction may be revealed by the effects of highly sensitive aqueous alteration processes, while physical processes may be recorded through aeolian abrasion effects. Over the past 2000 sols, the two Mars Exploration Rover (MER) spacecraft have formally identified a minimum of 11 meteorite candidates [1-3], with many more unofficial candidates likely, posing an intriguing set of questions concerning their chemical, mineralogical, and morphological conditions. Five meteorite candidates, including the newly discovered MER-B rock Block Island, and one confirmed meteorite [Meridiani Planum (MP; originally Heat Shield Rock)] [4] have been investigated with the rover arm instruments. All contain levels of ferric iron, which should not be present in pristine samples (i.e. without fusion crust and/or alteration phases). Moreover, preliminary morphologic evidence contributes to the case of possible chemical weathering in Block Island. Scrutiny of a Microscopic Imager (MI) mosaic of MP shows clear evidence for both localized aeolian sculpting, and the Widmanstätten pattern common to sliced and acid-etched surfaces of many iron-nickel meteorites. These latter features are manifest as millimeter-sized chevrons and subparallel linearities, most prominent across a partially brushed surface approximately 3 x 2 cm in area. Similar patterns are observed on a number of hot and cold desert meteorites (e.g. Drum Mountain and Ft. Stockton), and are attributed to physical ablation by sand grains differentially weathering the kamacite and taenite lamellae within the rock. A similar or identical process is interpreted as responsible for the features observed in MP. Other macro-scale features on MP are of questionable weathering origin. While some prefer a regmaglypt interpretation for the cavities in MP, others question whether differential weathering (either aqueous or physical) of softer sulfide (troilite) nodules or other inclusions such as schreibersite [5] in the metal matrix may be at least partly responsible. A discontinuous coating of darker material, interpreted to be oxide (though it is uncertain whether this is relict fusion crust or weathering rind), appears in the MI images also to have been polished and sculpted by abrasive forces. Laboratory experiments designed to address the requirements for iron shaping by wind abrasion would help provide constraints on the wind velocities involved in these processes. Preliminary results for Block Island display many features that are also consistent with aeolian abrasion. References: [1] Schröder C. et al. (2008) JGR 113, E06S22, doi:10.1029/2007JE002990. [2] Ashley J. W. et al. (2009) LPSC XL. [3] Schröder C. et al. (2009) LPSC XL. [4] Connolly H.C.J. et al. (2006) Meteoritical Bulletin #90, Meteoritics and Planet Sci. 41(9): p. 1383-1418. [5] Fleischer I. et al. (2009) Meteoritics and Planet Sci. 44, p. A70.

Ashley, J. W.; McCoy, T. J.; Schröder, C.

2009-12-01

74

Influence of weathering on shear strength of joints in a porphyritic granite rock mass in Jechon area, South Korea  

Microsoft Academic Search

The evolution of the shear strength of rock joints due to weathering processes is evaluated in terms of the joint wall compressive\\u000a strength (JCS) and residual friction angle. Laboratory direct shear tests were performed on 32 porphyritic granite joints\\u000a sampled from granitic rock slopes along a highway in the area of Jechon in South Korea. These samples were classified according

Ik Woo; Jean-Alain Fleurisson; Hyuck-Jin Park

2010-01-01

75

Effect of soil-rock system on speleothems weathering in Bailong Cave, Yunnan Province, China*  

PubMed Central

Bailong Cave with its well-developed Middle Triassic calcareous dolomite’s system was opened as a show cave for visitors in 1988. The speleothem scenery has been strongly weathered as white powder on the outer layers. Study of the cave winds, permeability of soil-rock system and the chemical compositions of the dripping water indicated: (1) The cave dimension structure distinctively affects the cave winds, which were stronger at narrow places. (2) Based on the different soil grain size distribution, clay was the highest in composition in the soil. The response sense of dripping water to the rainwater percolation was slow. The density of joints and other openings in dolomite make the dolomite as mesh seepage body forming piles of thin and high columns and stalactites. (3) Study of 9 dripping water samples by HYDROWIN computer program showed that the major mineral in the water was dolomite.

Wang, Jing; Song, Lin-hua

2005-01-01

76

Excavatability Assessment of Weathered Sedimentary Rock Mass Using Seismic Velocity Method  

SciTech Connect

Seismic refraction method is one of the most popular methods in assessing surface excavation. The main objective of the seismic data acquisition is to delineate the subsurface into velocity profiles as different velocity can be correlated to identify different materials. The physical principal used for the determination of excavatability is that seismic waves travel faster through denser material as compared to less consolidated material. In general, a lower velocity indicates material that is soft and a higher velocity indicates more difficult to be excavated. However, a few researchers have noted that seismic velocity method alone does not correlate well with the excavatability of the material. In this study, a seismic velocity method was used in Nusajaya, Johor to assess the accuracy of this seismic velocity method with excavatability of the weathered sedimentary rock mass. A direct ripping run by monitoring the actual production of ripping has been employed at later stage and compared to the ripper manufacturer's recommendation. This paper presents the findings of the seismic velocity tests in weathered sedimentary area. The reliability of using this method with the actual rippability trials is also presented.

Bin Mohamad, Edy Tonnizam; Noor, Muhazian Md; Isa, Mohamed Fauzi Bin Md.; Mazlan, Ain Naadia [Department of Geotechnics and Transportation, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai. Johor (Malaysia); Saad, Rosli [Universiti Sains Malaysia, Penang (Malaysia)

2010-12-23

77

Weathering  

NSDL National Science Digital Library

This interactive Flash resource provides information regarding physical and chemical weathering at an introductory physical geology or Earth science level. It includes animations, diagrams, and supplementary information and is suitable for high school or undergraduate students.

Smoothstone; Mifflin, Houghton

78

Role of fractures in weathering of solid rocks: narrowing the gap between laboratory and field weathering rates  

NASA Astrophysics Data System (ADS)

A weathering study of a fractured environment composed of granites and metasediments was conducted in Trás-os-Montes and Alto Douro (north of Portugal) and covered the hydrographic basin of Sordo river. Within the basin, a number of perennial springs were monitored for discharge rate, which allowed for the estimation of annual recharges. A small area of the basin was characterized for parameters such as hydraulic conductivity and effective porosity, which, in combination with the previously calculated recharges, allowed for the calculation of a fracture surface area. The monitored springs were also sampled and analyzed for major inorganic compounds, and using a mole balance model the chemistry of the water samples was explained by weathering to kaolinite of albite oligoclase plus biotite (granites) or of albite plus chlorite (metasediments). The number of moles of dissolved primary minerals (e.g. albite) could be calculated using this method. These mass transfers were then multiplied by the spring's median discharge rate and divided by the fracture surface area to obtain a weathering rate. Another weathering rate was determined, but using a BET surface area as normalizing factor. Comparing both rates with a representative record of laboratory as well as of field-based weathering rates, it has been noted that rates normalized by the BET were, as expected, similar to commonly reported field-based rates, whereas rates normalized by the fracture surface area were unexpectedly relatively close to laboratory rates (one order of magnitude smaller). The monitored springs are of the fracture artesian type, which means that water emerging at the spring site flowed preferentially through joints and fractures and that weathering took place predominantly at their walls. Consequently, it was concluded that the most realistic weathering rates are those normalized by the fracture surface area, and as a corollary that the gap between laboratory and field weathering rates might not be as wide as usually is reported to be.

Pacheco, Fernando A. L.; Alencoão, Ana M. P.

2006-01-01

79

Studies of Fe/sup 2 +/. -->. Fe/sup 3 +/ transitions during the process of rock weathering by nuclear gamma-resonance spectroscopy  

SciTech Connect

This paper presents a method for the mineral and weathering assessment of rocks and carbonaceous matter based in gamma spectroscopy and transitions between iron ions. The method is applied to rocks collected near the Teberda preserve. Four latitudinal bands of rocks parallel to the Greater Caucasus Ridge are identified in this territory. Isomer shift and hyperfine parameters of the Moessbauer spectra are given.

Vasil'ev, S.P.; Babanin, V.F.; Solov'ev, A.A.

1986-11-01

80

Worldwide distribution of continental rock lithology: Implications for the atmospheric\\/soil CO2 uptake by continental weathering and alkalinity river transport to the oceans  

Microsoft Academic Search

The silicate rock weathering followed by the formation of carbonate rocks in the ocean, transfers CO2 from the atmosphere to the lithosphere. This CO2 uptake plays a major role in the regulation of atmospheric CO2 concentrations at the geologic timescale and is mainly controlled by the chemical properties of rocks. This leads us to develop the first world lithological map

Philippe Amiotte Suchet; Jean-Luc Probst; Wolfgang Ludwig

2003-01-01

81

Behavior of major and trace elements upon weathering of peridotites in New Caledonia : A possible site on ultramafic rocks for the Critical Zone Exploration Network (CZEN) ?  

Microsoft Academic Search

Ultramafic rocks cover about 1% of the continental surfaces and are related to ophiolitic bodies formed near convergent plate boundaries (Coleman, 1977). The most typical ultramafic rocks are dunite and harzburgite, which are composed of easily weatherable ferromagnesian mineral species (olivines and pyroxenes), but also of more resistant spinels (chromite and magnetite). Oceanic serpentinization of these ultramafic rocks usually lead

Farid Juillot; D. Fandeur; E. Fritsch; G. Morin; J. P. Ambrosi; L. Olivi; A. Cognigni; J. L. Hazemann; O. Proux; S. Webb; G. E. Brown Jr.

2010-01-01

82

Erosion rates and weathering history of rock surfaces associated with Aboriginal rock art engravings (petroglyphs) on Burrup Peninsula, Western Australia, from cosmogenic nuclide measurements  

NASA Astrophysics Data System (ADS)

The Burrup Peninsula and surrounding Dampier Archipelago, in Western Australia, contain the world's largest known gallery of rock art engravings (petroglyphs), estimated to number up to 1 million images. The peninsula is also the site of major industrial development and there are concerns that industrial emissions may adversely affect the stability and longevity of the rock art. We have studied the natural processes and rates of weathering and erosion, including the effects of fire, that affect the stability of rock surfaces and hence the longevity of the rock art, using cosmogenic nuclides. The concentration of 10Be in quartz yields erosion rates in the range 0.15–0.48 mm/1000 years on horizontal rock surfaces and 0.34–2.30 mm/1000 years on vertical rock faces. The former, largely caused by mm-scale surface flaking, are amongst the lowest erosion rates measured by cosmogenic nuclides anywhere in the world. The latter are inferred to represent a combination of mm-scale flaking and very rare centimetre- to metre-scale block falls, controlled by failure along joint planes. Such low erosion rates result from a combination of resistant rocks, low relief and low rainfall, favouring long-term preservation of the petroglyphs – long enough to encompass the known period of human settlement in Australia.

Pillans, Brad; Fifield, L. Keith

2013-06-01

83

Re-Os isotope systematics and weathering of Precambrian crustal rocks: implications for the marine osmium isotope record  

NASA Astrophysics Data System (ADS)

The effects of weathering of freshly exposed Precambrian rocks on the mobility of osmium were studied on soils developed on a chronosequence of glacial moraines from the western Wind River Range in Wyoming. The Os budget of the Precambrian granitoid source rocks is dominated by Os-rich trace phases, such as magnetite. Amongst the major silicates, biotite, or a trace phase in biotite, carries most of the Os and Re and is also the most radiogenic mineral with 187Os/ 186Os of ˜113 and 187Re/ 186Os of ˜2,000. Re-Os isotope systematics of source rocks and soils indicate that rapid oxidation of magnetite mobilizes Os with an isotopic composition similar to the isotopic composition of the bulk soils. A very radiogenic fraction of Os is mobilized through preferential weathering of biotite. Radiogenic runoff from Precambrian shields, inferred from osmium isotope analyses of freshwater Fe-Mn-nodules suggests that high-latitude Precambrian shields are important source areas of radiogenic Os in seawater. We propose that glacial scouring and weathering of glacial tills exposed after deglaciation of Precambrian shields surrounding the North Atlantic provides a mechanism for the slightly more radiogenic nature of North Atlantic seawater compared to other seawater masses. Glacial-interglacial variations in the osmium isotopic composition of seawater seem plausible and may be triggered by changes in weathering regimes on glacial-interglacial time scales in high-latitude shield areas surrounding the North Atlantic.

Peucker-Ehrenbrink, Bernhard; Blum, Joel D.

1998-10-01

84

Salt-induced rock fragmentation on Mars: The role of salt in the weathering of Martian rocks  

Microsoft Academic Search

Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos (except: Meridiani landing side, which formed by different processes, and is therefore not considered in this paper). Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight

Emil Jagoutz

2006-01-01

85

External Resource: Mechanical Weathering  

NSDL National Science Digital Library

A student activity with teacher's sheet, to give the students an opportunity to realize that all rocks weather mechanically and each specific rock type has its own particular rate of weathering. Mechanical weathering is the process of breaking down bedroc

1900-01-01

86

Characterizing the process and quantifying the rate of subaerial rock weathering on desert surfaces using roughness analysis  

NASA Astrophysics Data System (ADS)

Subaerial weathering of rocks is a common process observed on desert surfaces on Earth and other planetary terrestrial surfaces such as on Mars. On Earth, this weathering process has been previously identified as one of the key erosion agent driving geomorphic surface evolution and the development of desert pavements. And yet, fundamental aspects of the process, such as the relative contribution of the different weathering modes that drive it (e.g., mechanical breakdown of rocks, chemical weathering, aeolian abrasion and exfoliation) as well as the rate by which this weathering process occurs have not been systematically examined. Here, we present a new approach for quantitatively addressing these fundamental aspects of process geomorphology on desert surfaces. We focus here on co-genetic desert alluvial surfaces of different ages, i.e. alluvial chronosequences, which provide excellent recorders for the evolution of boulder-strewn surfaces into smooth desert pavements through in-situ subaerial weathering of rocks. Our approach combines independent measures of two different surface attributes: High resolution (mm-scale) 3D ground-based laser scanning (LiDAR) of surface micro-topography, and numerical dating of surface age. Roughness analysis of the LiDAR data in power spectral density (PSD) space allows us to characterize the geometric manifestation of rock weathering on the surface and to distinguish between the different weathering modes. Numerical age constraints provide independent estimates for the time elapsed since the process began. Accordingly, we are able to constrain surface roughness evolution on alluvial fan desert chronosequences through time, and present PSD analysis of surface roughness as a new quantitative tool to examine the process of subaerial rock weathering in desert environments. In this study we present results from two late Quaternary alluvial chronosequences along the Dead Sea Transform in the hyper-arid Negev desert of southern Israel. LiDAR scanning was applied on representative areas (~30-50 m2) of 10 separate surfaces ranging from rough Holocene surfaces to fairly smooth surfaces with well-developed pavements displaying an OSL age of 87 kyr. We find typical and recurring time-dependent changes in the offset as well as shape of the PSD curves in both chronosequences: PSD offset is continuously reduced over time reflecting the overall reduction in the amplitude of roughness at all wavelengths. The PSD curves display progressive moderation of slopes at the longer wavelengths with the moderation point itself systematically shifted to shorter wavelengths. This characteristic evolution of PSD offset and slope moderation at longer wavelengths reflects the typical break up of boulder-sized clasts through time as the surfaces mature into well-developed desert pavements and points towards mechanical breakdown as the dominant weathering mode. In addition, we are able to determine the rate by which the larger clasts are removed from the system. We build on these new insights into process and rate of rock weathering to propose PSD analysis of surface roughness as a complementary method for constraining the age of desert alluvial surfaces in places where 'conventional' dating cannot be applied.

Mushkin, Amit; Sagy, Amir; Trabelci, Eran

2013-04-01

87

Role of fractures in weathering of solid rocks: narrowing the gap between laboratory and field weathering rates  

Microsoft Academic Search

A weathering study of a fractured environment composed of granites and metasediments was conducted in Trás-os-Montes and Alto Douro (north of Portugal) and covered the hydrographic basin of Sordo river. Within the basin, a number of perennial springs were monitored for discharge rate, which allowed for the estimation of annual recharges. A small area of the basin was characterized for

Fernando A. L. Pacheco; Ana M. P. Alencoão

2006-01-01

88

Weather  

NSDL National Science Digital Library

In the project you will learn about thunderstorms and tornadoes and play a weather matching game. What exactly are thunderstorms and tornadoes? Use your T- chart to explain some facts about a thunderstorm and a tornado as we review each. T-Chart Begin by reviewing what a thunderstorm is and how they form. Thunderstorm information What is a thunderstorm? What are thunderstorms most likely to occur? What causes thunder? Next review what a tornado ...

Caitlin, Ms.

2009-10-21

89

Weathering Animation  

NSDL National Science Digital Library

Weathering is the term that describes all the processes that break down rocks in the environment near the Earth's surface. This module will help you to understand two weathering processes: mechanical and chemical.

2002-01-01

90

Worldwide distribution of continental rock lithology: Implications for the atmospheric/soil CO2 uptake by continental weathering and alkalinity river transport to the oceans  

NASA Astrophysics Data System (ADS)

The silicate rock weathering followed by the formation of carbonate rocks in the ocean, transfers CO2 from the atmosphere to the lithosphere. This CO2 uptake plays a major role in the regulation of atmospheric CO2 concentrations at the geologic timescale and is mainly controlled by the chemical properties of rocks. This leads us to develop the first world lithological map with a grid resolution of 1° × 1°. This paper analyzes the spatial distribution of the six main rock types by latitude, continents, and ocean drainage basins and for 49 large river basins. Coupling our digital map with the GEM-CO2 model, we have also calculated the amount of atmospheric/soil CO2 consumed by rock weathering and alkalinity river transport to the ocean. Among all silicate rocks, shales and basalts appear to have a significant influence on the amount of CO2 uptake by chemical weathering.

Amiotte Suchet, Philippe; Probst, Jean-Luc; Ludwig, Wolfgang

2003-06-01

91

Synchrotron-based redox behavior of chromium during weathering of ultramafic rocks in New-Caledonia  

NASA Astrophysics Data System (ADS)

In New-Caledonia, deep weathering of ultramafic rocks (peridotites) has lead to the development of thick lateritic regoliths where Ni, Cr, Co and Mn can exhibit concentration up to several wt%. Such a large occurrence of these potentially toxic elements can represent serious risks for the environmental quality of this ‘' biodiversity hotspot'' and actual risk assessment relies on our capacity at characterizing the natural cycling of these elements. The present study reports the results of a detailed XANES analysis on the redox chemistry of Cr along a 64 meters depth lateritic regolith developed in the ultramafic rocks of the Koniambo outcrops located on the western coast of New Caledonia. In a first step, bulk XAS data at both the Cr and Mn K-edges have been used to evidence a remarkable correlation between the occurrence of Mn(III,IV)-oxides (mainly asbolane) and that of Cr(VI), at the scale of the studied regolith (Fandeur et al., 2009a). Since Cr mainly occurs as Cr(III)-bearing silicates in the ultramafic bedrock, such a correlation strongly suggests an oxidation of the fraction of Cr(III) released upon the weathering of these silicates to Cr(VI) by the Mn(III,IV)-oxides, as already demonstrated in laboratory studies (Oze et al., 2008). In a second step, µ-XANES mapping of the Cr redox at the boundary between Mn(III,IV)-oxides and Fe(III)-oxyhydroxides (mainly goethite) allowed to depict the actual behavior of Cr(VI) after oxidation. Results indicate an association of Cr(VI) with both Mn-oxides and Fe-oxyhydroxides which suggests that, after oxidation of Cr(III) to Cr(VI) by the Mn(III,IV)-oxides, part of oxidized chromium is desorbed from these Mn-oxides and transported to the surrounding Fe-oxyhydroxides where it accumulates through sorption reactions (Fandeur et al., 2009b). Such a redox-sorption pathway has been confirmed by reacting aqueous Cr(III) with birnessite alone or with a mixture of birnessite and goethite during time-resolved laboratory experiments. This complex sorption/oxidation/desorption/re-sorption pathway suggests that, in lateritic regoliths, the enhancement of the mobility of Cr possibly induced by its oxidation after sorption on Mn(III,IV)-oxides could be significantly limited by sorption of Cr(VI) onto surrounding Fe(III)-oxyhydroxides. This work has been supported by the French ANR-ECCO program. References Fandeur D., Juillot F., Morin G., Olivi L., Cognigni A., Webb S., Ambrosi J.P., Fritsch E. and Brown Jr. G.E. (2009a). XANES evidence for oxidation of Cr(III) to Cr(VI) by Mn-oxides in a lateritic regolith developed on serpentinized ultramafic rocks in New Caledonia. Environmental Science and Technology, submitted. Fandeur D., Juillot F., Morin G., Webb S., Hazemann J.L., Proux O., Olivi L., Cognigni A., Ambrosi J.P., Fritsch E., Guyot F. and Brown Jr G.E. (2009b). Crystal-chemistry of Cr and Mn and specific behavior of Cr(VI) after oxidation by Mn-oxides along a lateritic regolith from New Caledonia. Geochimica Cosmochimica Acta, submitted. Oze, C.; Bird, D. K.; Fendorf, S. Genesis of hexavalent chromium from natural sources in soil and groundwater. Proc. Nat. Acad. Sci. 2007, 104, 6544-6549.

Juillot, Dr.; Fandeur, Dr.; Fritsch, Dr.; Morin, Dr.; Olivi, Dr.; Webb, Dr.; Hazemann, Dr.; Ambrosi, Dr.; Brown, Jr., Dr.

2009-04-01

92

A model for simulating rock–water interactions in a weathering profile subjected to frequent alternations of wetting and drying  

Microsoft Academic Search

Physically based equations for unsaturated groundwater flow and solute transport have been coupled with kinetic rate laws for mineral dissolution–precipitation, and mass balance\\/mass action equations for aqueous species, in a numerical model that is capable of simulating rock–water interactions in a weathering profile subjected to fluctuating boundary conditions. A numerical experiment was conducted to demonstrate how incipient soil development may

Nasser Alsaaran; Greg A. Olyphant

1998-01-01

93

Rain, rock moisture dynamics, and the rapid response of perched groundwater in weathered, fractured argillite underlying a steep hillslope  

NASA Astrophysics Data System (ADS)

Various field studies have concluded that shallow groundwater in weathered bedrock underlying hillslopes can contribute to both base and stormflow and thus dominate runoff. The processes associated with recharge from the ground surface, through this unsaturated zone, have received little study, yet they influence runoff dynamics, the chemical evolution of water, and moisture availability. Here we use five measurement systems to document soil and rock moisture dynamics within a 4000 m2zero-order basin in which all runoff occurs through weathered argillite. At this site, the weathered bedrock zone (in which the groundwater fluctuates by 8 m seasonally) varies in depth from ˜4 m at the base of the hillslope to nearly 19 m near the hill top. An aggregate-rich, porous, 0.5 m thick soil overlies the weathered bedrock. We find that during the first rains of the wet season, water rapidly travels meters into the weathered bedrock zone. Consistently, however, groundwater at some places responds quickly to the first major storm, well before the wetting front has been detected much beyond about 1 m. Furthermore, throughout the wet season, the lower portion of the unsaturated weathered bedrock shows little or no moisture change. These observations suggest a fracture-dominated flow path, leading to a highly variably groundwater response across the hillslope for a given storm. Seasonal changes in rock moisture content are greatest in the first 5 to 10 m depth and may exceed the magnitude of moisture changes in the soil, suggesting that it could constitute a significant unmapped moisture reservoir.

Salve, Rohit; Rempe, Daniella M.; Dietrich, William E.

2012-11-01

94

Regolith Evolution Influences Element Redistribution During Weathering of Volcanic Rocks in Erosional, Sedentary, and Depositional Landscapes: Examples From Hawai'i, Guatemala and Southeastern Australia  

NASA Astrophysics Data System (ADS)

This study examines the weathering of volcanic rocks exemplifying each of three landscape/regolith associations (erosional, sedentary/relict/residual, and depositional), and illustrates how the regolith/landscape associations and their geomorphic evolution influence the geochemical evolution of the regolith. In erosional landscapes, the rate of physical erosion exceeds the rate of chemical weathering of rock to altered regolith, and surface materials consist of fresh or minimally weathered bedrock. Recent basalts (<4ka) from Hawai'i have weathered slightly and have accumulated no weathering rinds, saprolite, or allochthonous regolith over their brief exposure history. Whole-rock geochemistry is not affected by the small amount of chemical weathering. Leaching has been insufficient for differential removal of elements, and there are no elemental sources outside of the nearly fresh outcrops from which elements might have been introduced into the exposed volumes. In sedentary/relict/residual landscapes, the rate of chemical weathering equals or exceeds the rate of physical erosion, and surface material consists of deeply weathered saprolite. Some volcanic rocks of Plio-Pleistocene age from Hawai'i and Guatemala have experienced spheroidal or corestone weathering, in which corestones of minimally weathered rock are surrounded by concentric saprolitic shells and saprolite derived from the decomposition of the volcanic rock. Many major elements and some minor elements (REE) are depleted from the saprolitic portions of these regoliths. However, several of these minor elements (REE) are enriched in the inner portions of corestone-shell complexes, suggesting that these minor elements and REE leached from saprolite are transferred within the regolith to secondary minerals formed during incipient weathering of the corestones. In depositional landscapes, the surficial material consists of sediment (colluvial, fluvial/alluvial, or aeolian). Tertiary volcanic rocks of the Monaro Volcanic Province (New South Wales, Australia) were emplaced in fluvial-lacustrine environments and almost immediately covered by fine-grained clastic sediment. The jointed flows weathered spheroidally. Corestones have essentially fresh major element and REE signatures. However, Zr (probably redistributed physically from the fine-grained sediment) exhibits systematic absolute enrichment with progressive weathering in the Monaro corestone-shell complexes. Weathering of volcanic rocks results in geochemical trends that differ systematically with the presence, nature, and extent of development of associated regolith. Geochemical patterns of element depletion and enrichment in individual samples and suites of samples can only be properly interpreted if the regolith/landscape context of the samples is taken into account.

Velbel, M. A.; Patino, L. C.; Price, J. R.; Wade, J. A.

2004-12-01

95

A study of the depth of weathering and its relationship to the mechanical properties of near-surface rocks in the Mojave Desert  

USGS Publications Warehouse

Weathered granite extends 70 m deep at Hi Vista in the arid central Mojave Desert of southern California. The low strength of this granite is due to the alteration of biotite and chlorite montmorillonite. Deep weathering probably occurs in most granites, although we cannot rule out some anomalous mechanisms at Hi Vista. Geophysical instruments set in these slightly altered rocks are limited by the unstable behavior of the rocks. Thus, tectonic signals from instruments placed in shallow boreholes give vague results. Geophysical measurements of these weathered rocks resemble measurements of granitic rocks near major faults. The rheology of the rocks in which instruments are placed limits the useful sensitivity of the instruments. ?? 1985 Birkha??user Verlag.

Stierman, D. J.; Healy, J. H.

1985-01-01

96

Thermal infrared analysis of weathered granitic rock compositions in the Sacaton Mountains, Arizona: Implications for petrologic classifications from thermal infrared remote-sensing data  

Microsoft Academic Search

Received 9 October 2003; revised 28 January 2004; accepted 11 February 2004; published 18 March 2004. (1) Critical to spectral interpretations of geologic surfaces on the Earth and Mars is an understanding of the relationship between the composition of weathered rock surfaces and whole-rock mineralogy. In this study, thermal infrared spectroscopic and remote-sensing analyses were used to determine the composition

Joseph R. Michalski; Stephen J. Reynolds; Thomas G. Sharp; Philip R. Christensen

2004-01-01

97

Rocks  

NSDL National Science Digital Library

This year we are going to learn about rocks. Do you like to collect rocks? Rocks are the most common material on earth. We will learn about the parts that make up the rocks and sort rocks based upon color, hardness, texture, layering, and particle size. So you want to learn about rocks? Go to Intro to Rocks for some fascinating facts about rocks! Now lets learn about some of the different kinds of rocks. Igneous Rocks Metamorphic Rocks Sedimentary Rocks Click here to see the differences between the types of rocks that you have learned about What Type Of Rock Do I Have?. After doing all the activities above, ...

Woodruff, Mrs.

2010-06-21

98

Nutrient Release from Weathering of Purplish Rocks in the Sichuan Basin, China 1 1 Project supported by the National Basic Research Program of China (No. 2003CB415202) and the National Natural Science Foundation of China (Nos. 40571093 and 49601009)  

Microsoft Academic Search

Purplish soils having high fertility with mineral nutrients inherited from the parent rock are widely distributed in the hills along the Yangtze River, especially in the Sichuan Basin. Pot and field weathering experiments were conducted to mimic rock weathering and nutrient release processes in order to better understand soil fertility and nutrient compensation. Three types of purplish rock formations formed

Bo ZHU; Tao WANG; Xiang YOU; Mei-Rong GAO

2008-01-01

99

Rock and stone weathering at Citadel fortifications, Gozo (Malta): benefits from terrestrial laser scanning combined with conventional investigations  

NASA Astrophysics Data System (ADS)

Military architecture heritage is frequently built on rock masses affected by slope instability and weathering processes, which progressively undermine the foundations and cause collapses and toppling of the masonries. The latter can be also weakened by alteration of the stone surfaces, as a consequence of the interactions with the local environmental conditions. These conservation issues are emphasized for those sites, whose susceptibility to structural damages is also due to the similarity between the lithotypes constituting the geologic substratum and the construction materials. Effective solutions for the protection from such a type of phenomena can be achieved if the whole "rock mass - built heritage system" is analyzed. In this perspective, we propose a new approach for the study of the weathering processes affecting historic hilltop sites, taking benefits from the combination of terrestrial laser scanning (TLS) and conventional investigations, the latter including geotechnical and minero-petrographic analyses. In particular, the results here presented were obtained from specific tests on the fortifications of Citadel, Gozo (Malta), performed in co-operation with the Restoration Unit, Works Division, Maltese Ministry for Resources and Rural Affairs and the private company Politecnica Ingegneria e Architettura. The Citadel fortifications are built at the top of a relatively stiff and brittle limestone plate, formed by Upper Coralline Limestone (UCL) and overlying a thick Blue Clay (BC) layer. Differential weathering creates extensively fractured ledges on the cap and erosion niches in the strata beneath, thereby favouring block detachment, even rockfall events, such as the last one occurred in 2001. The locally quarried Globigerina Limestone (GL), historically employed in restoration masonries, is also exposed to alveolization and powdering, and several collapses damaged the underwalling interventions. Since the erosion pattern distribution suggested a correlation with the structural setting of the rock mass and the mineralogical properties of the limestones, an overall weathering study was carried out, by combining surface surveys with analyses of the inner structure. A holistic TLS point cloud of Citadel, produced by Consorzio Ferrara Ricerche of the University of Ferrara and made available by the Restoration Unit, was exploited to perform a 3D quantitative kinematic analysis of the entire rock mass. Each sector was classified in relation to the probability of occurrence of instability mechanisms, among which plane failure, block toppling and wedge failure. The latter was found associated with the highest index measured (30%), followed by the flexural toppling mechanism (17%), providing a confirmation to the field survey and the results of geotechnical analyses. The integration with geologic and diagnostic investigations (e.g., boreholes, thin section observations) highlighted the intrinsic weaknesses of the rocks and stones to weathering, with a quite unexpected higher susceptibility to erosion and disaggregation characterizing the inner layers. Hence, the textural appearance of the erosion surfaces, the rock/stone structural properties and the TLS-based classification of the cliff sectors were mutually correlated, and the most unstable areas were mapped. As main implication for the conservation, on site monitoring system (i.e., biaxial inclinometers and crack gauges) was installed and targeted restorations have been properly designed.

Tapete, D.; Gigli, G.; Mugnai, F.; Vannocci, P.; Pecchioni, E.; Morelli, S.; Fanti, R.; Casagli, N.

2012-04-01

100

Microbial Weathering of Igneous Rocks: A Tool for Locating Past Life on Mars  

Microsoft Academic Search

Some microbes are capable of living in terrestrial igneous rocks, and similar environments exist on Mars. Evidence for microbe on Mars could be found in volcanic glass in ejecta, quenched lavas, or shock melted meteorites.

M. R. Fisk; S. J. Giovannoni

1999-01-01

101

Enhanced chemical weathering of rocks during the last glacial maximum: a sink for atmospheric CO 2?  

Microsoft Academic Search

It has been proposed that increased rates of chemical weathering and the related drawdown of atmospheric CO2 on the continents may have at least partly contributed to the low CO2 concentrations during the last glacial maximum (LGM). Variations in continental erosion could thus be one of the driving forces for the glacial\\/interglacial climate cycles during Quaternary times. To test such

Wolfgang Ludwig; Philippe Amiotte-Suchet; Jean-Luc Probst

1999-01-01

102

Comparison of rate of physical and chemical decomposition of rocks in weathering by wetting-drying and wetting-freezing-drying cycles  

NASA Astrophysics Data System (ADS)

The type and amount of weathering is determined by a complex combination of physico-chemical properties of the material and climatic conditions. Different materials respond differently in the same environments, but also the same materials can respond in different ways to the same processes in different environments. Weathering processes are often acting simultaneously at one site and it is sometimes hard to determine the exact weathering process that resulted in a certain weathering product. Rock characteristics, alternation of wetting and drying cycles and presence of joints and fissures are crucial for weathering processes. However, there is a big difference in the material response to precipitation depending on whether or not it is followed by freezing when more deterioration occurs. In order to study in detail the behaviour of different rocks under moisture and temperature regimes, weathering experiments with multiple cycles were carried out. The aim of these experiments was to obtain data about dynamics of decomposition of rocks under controlled laboratory conditions. Six rocks were selected for the weathering experiments due to their geological setting in mountain regions and their physico-chemical and mineralogical characteristics: red and grey sandstone (Germany), red sandstone (Serbia), tuffaceous rock (Island), gabbro (Serbia), and dunite (Germany). Samples of each of these rocks were examined in two separate experimental sets. First set consisted of 10 identical cycles that included 4 steps: raining, freezing, thawing and drying. After each step, sample mass was measured. Second set also had 10 cycles, but consisted of two steps: raining and drying. Leachate was collected after each cycle during both sets and volume, pH and conductivity was measured. Contents of Ca, K, Mg, Si, Al and Fe were determined in collected leachate after cycles 1, 5 and 10. Leachate characteristics were similar in both experimental sets. Volume, conductivity and pH of leachate were constant throughout all cycles. Furthermore, the concentrations of analyzed elements in the leachate were low throughout both sets of the experiment. As expected, freezing of samples did not show significant influence on concentration of tested elements in the leachate. However, the rate of mass loss differentiated samples from two experimental sets. Mass loss in samples submitted to freezing was constantly increasing with the number of cycles for all tested rocks. According to mass loss, dunite was most quickly deteriorating from all tested rocks during both experimental sets. Dunite lost about twice as much mass when frozen then when rained on. Both red sandstones behaved similarly to dunite. On the contrary, mass loss in grey sandstone, tuffaceous rock and gabbro during raining was <1%, but increased 4 times with freezing. Rock characteristics crucial for weathering are mineralogical composition and physico-mechanical characteristics. Obtained results indicate that the physical weathering processes are important in all tested rocks. Furthermore, they indicate that the rate of physical weathering during rainfall is not an indication of deterioration that will occur during freezing. Key words: weathering experiment, raining, freezing, rocks

Vezmar, T.; Kasanin-Grubin, M.; Kuhn, N. J.; Milovanovic, D.

2012-04-01

103

Weathering and deterioration of rock properties of the Dabotap pagoda (World Cultural Heritage), Republic of Korea  

Microsoft Academic Search

The Bulkugsa Dabotap pagoda was built in AD 761, and designated as World Cultural Heritage by UNESCO in 1995. The ca. 270 blocks used in the construction of the pagoda consist mainly of white grey alkali granite with medium-grained equi-granular texture and small mialolitic cavities. Small quantities of biotite granite, granodiorite, gabbroic and tuffaceous rocks were also used. Some overlapping

Chan Hee Lee; Myeong Seong Lee; Mancheol Suh; Seok-Won Choi

2005-01-01

104

Modelling Compositional Change: The Example of Chemical Weathering of Granitoid Rocks  

Microsoft Academic Search

Perturbation on the simplex is an operation which can be used to numerically describe changes in the composition of, for example, soils, sediments, or rocks. The combination of perturbation and power transformation provides a strong tool for analyzing compositional linear processes in the simplex. When the process is constrained in the sense of a well-known starting (or final) composition, noncentred

Hilmar von Eynatten; Carles Barceló-Vidal; Vera Pawlowsky-Glahn

2003-01-01

105

Weathering of Igneous, Metamorphic, and Sedimentary Rocks in a Semi-Arid Climate - An Engineering Application of Petrology  

NSDL National Science Digital Library

The identification of clay mineral assemblages in soils provides a unique opportunity to demonstrate how basic principles of petrology and geochemistry are applied to engineering design criteria in construction site preparation. Specifically, the problem investigates the conditions leading to the formation of smectite in soils and the resulting construction risk due to soil expansion. Students examine soils developed on igneous, metamorphic, and sedimentary rocks near Denver, Colorado. The field locations are areas of suburban growth and several have expansive soil problems. The 2-week exercise includes sample collection, description, and preparation, determining clay mineralogy by XRD, and measurement of Atterberg Plasticity Indices. This problem develops skills in X-ray diffraction analysis as applied to clay mineralogy, reinforces leacture material on the geochemistry of weathering, and demonstrates the role of petrologic characterization in site engineering.

Harrison, Wendy; Wendlandt, Ric

106

The Effects of Fire on Rock Art: Microscopic Evidence Reveals the Importance of Weathering Rinds  

Microsoft Academic Search

This paper presents results of the first study of pre-fire and post-fire samples collected from rock engravings and adjacent sandstone joint faces. A 2001 wildfire at Whoopup Canyon, Wyoming, stimulated a comparison of 1991 and 2003 samples. Opti- cal microscopy of ultra-thin sections, backscattered electron microscopy, x-ray (energy dispersive and wavelength dispersive) analysis of cross sections, and high-resolution trans- mission

Alice M. Tratebas; Niccole Villa Cerveny; Ronald I. Dorn

2004-01-01

107

Rare earth element geochemistry of sulphide weathering in the São Domingos mine area (Iberian Pyrite Belt): A proxy for fluid–rock interaction and ancient mining pollution  

Microsoft Academic Search

Gossan, disseminated orebody waste, other mining wastes, minesoils and acid mine drainage (AMD) in the abandoned São Domingos mine area (Iberian Pyrite Belt, IPB) have been analyzed for rare earth elements (REE). The main aim is to understand REE mobility during sulphide weathering so that the lanthanide series can be used both as a record of the water–rock interaction and

Rafael Pérez-López; Joaquín Delgado; José Miguel Nieto; Belén Márquez-García

2010-01-01

108

Use of hydraulic tests at different scales to characterize fracture network properties in the weathered-fractured layer of a hard rock aquifer  

Microsoft Academic Search

The hydrodynamic properties of the weathered-fractured layer of a hard-rock pilot watershed in a granitic terrain are characterized using hydraulic tests at different scales. The interpretation of numerous slug tests leads us to characterize the statistical distribution of local permeabilities in the wells. The application of flowmeter profiles during injection tests determines the vertical distribution of conductive fracture zones and

J. C. Maréchal; B. Dewandel; K. Subrahmanyam

2004-01-01

109

Behavior of major and trace elements upon weathering of peridotites in New Caledonia : A possible site on ultramafic rocks for the Critical Zone Exploration Network (CZEN) ?  

NASA Astrophysics Data System (ADS)

Ultramafic rocks cover about 1% of the continental surfaces and are related to ophiolitic bodies formed near convergent plate boundaries (Coleman, 1977). The most typical ultramafic rocks are dunite and harzburgite, which are composed of easily weatherable ferromagnesian mineral species (olivines and pyroxenes), but also of more resistant spinels (chromite and magnetite). Oceanic serpentinization of these ultramafic rocks usually lead to partial transformation of these initial mineral assemblages by forming hydrous layer silicates such as serpentine (lizardite, chrysotile and antigorite) talc, chlorite and actinolite (Malpas, 1992). It also lead to the formation of highly sheared textures, which favor meteoric weathering through preferential water flows. Compared to their crystalline rock counterpart that covers most of the continental surfaces, these ultramafic rocks mainly differ by their lower SiO2, Al2O3 and K2O contents (less than 50%, 10% and 1%, respectively) and, on the opposite, much higher MgO content (more than 18%). Moreover, they commonly have higher concentrations in FeO and other trace elements, such as Ni, Cr, Mn and Co. Weathering of these rocks is then at the origin of major geochemical anomalies on continental surfaces, especially when they occur in tropical and subtropical regions. Such conditions are encountered in New Caledonia where one third of the surface is covered with peridotites (mainly harzburgite with small amounts of dunite) obducted about 35 millions years ago during large tectonic events in the Southwest Pacific at the Late Eocene (Cluzel et al., 2001). Tropical weathering of these ultramafic rocks lead to the development of thick lateritic regoliths where almost all Mg and Si have been leached out and Fe, Mn, Ni, Cr and Co have been relatively concentrated. In these oxisols, Ni, Cr and Co can exhibit concentration up to several wt%, which make them good candidates for ore mining (New Caledonia is the third Ni producer in the world). However, these high concentration of potentially toxic elements can represent a serious hazard for the environmental quality of the Caledonian ecosystem which is a '' biodiversity hotspot' (Myers, 2000), which emphasize the strong need for characterizing the natural cycling of these elements upon weathering of ultramafic rocks. To reach this goal, we have studied the mineralogical distribution, crystal-chemistry and mass balance modelling of major (Si, Mg, Al, Fe, Mn) and trace elements (Ni, Cr and Co) in the freely-drained weathering profile developed in the serpentinized harzburgites of Mt Koniambo (West Coast of New Caledonia). Results show that both hydrothermal and meteoric processes contributed to the vertical differentiation of this freely drained weathering profiles in serpentinized ultramafic rocks. Finally, they also emphasize the importance of both redox reactions and interactions with Mn- and Fe-oxyhydroxydes (Fandeur et al., 2009a; 2009b) to explain the opposite behavior observed between very mobile Ni and almost immobile Cr (Fandeur et al., 2010). These results bring new insights on the geochemical behavior of trace elements upon weathering of ultramafic rocks under tropical conditions leading to the formation of supergene ore deposits. They also emphasize the interest of such a weathering site on ultramafic rocks under tropical climate to complemente the reference sites of the Critical Zone Exploration Network (CZEN). References Cluzel D., Aitchinson J.C. and Picard C. (2001) Tectonic accretion and underplating of mafic terranes in the Late Eocene intraoceanic fore-arc of New-Caledonia (Southwest Pacific): geodynamic implications. Tectonophysics, 340, 23-59. Coleman, R.G. (1977) Ophiolites: Ancient oceanic lithosphere?: Berlin, Germany, Springer-Verlag, 229p. Fandeur D., Juillot F., Morin G., Olivi L., Cognigni A., Fialin M., Coufignal F., Ambrosi J.P., Guyot F. and Fritsch E. (2009a). Synchrotron-based speciation of chromium in an Oxisol from New-Caledonia : Importance of secondary Fe-oxyhydroxydes. American Mineralogist, 94, 710-719. Fandeur

Juillot, Farid; Fandeur, D.; Fritsch, E.; Morin, G.; Ambrosi, J. P.; Olivi, L.; Cognigni, A.; Hazemann, J. L.; Proux, O.; Webb, S.; Brown, G. E., Jr.

2010-05-01

110

Efficacy of nanolime in restoration procedures of salt weathered limestone rock  

NASA Astrophysics Data System (ADS)

Salt crystallisation process is one of the most powerful weathering agents in stone materials, especially in the coastal areas, where sea-spray transports large amount of salts on the stone surface. The consolidation of such degraded stone material represents a critical issue in the field of restoration of cultural heritage. In this paper, the nanolime consolidation behaviour in limestone degraded by salt crystallization has been assessed. For this purpose, a stone material taken from a Sicilian historical quarry and widely used in the eastern Sicilian Baroque architecture has been artificially degraded by the salt crystallization test. Then degraded samples have been treated with NanoRestore®, a suspension of nanolime in isopropyl alcohol. To evaluate the consolidating effectiveness, the peeling test and point load test were performed. Moreover, mercury intrusion porosimetry has been executed to evaluate the variations induced by treatment, while colorimetric measurements have been aimed to assess aesthetical issues.

Ruffolo, Silvestro A.; La Russa, Mauro F.; Aloise, Piergiorgio; Belfiore, Cristina M.; Macchia, Andrea; Pezzino, Antonino; Crisci, Gino M.

2013-09-01

111

Rapid changes in the physical properties of rock and concrete during intertidal exposure; implications for weathering and engineering durability  

NASA Astrophysics Data System (ADS)

Water absorption is an important parameter affecting the susceptibility of rocky shore substrates and construction materials to wetting-drying, salt weathering and dissolution processes exposed in the intertidal zone. Strength is also an important determinant of durability and resistance to erosion processes such as abrasion. Here we examine changes in the water absorption properties and strength of representative materials used in the construction of coastal defences after 8 months exposure in the intertidal zone. Blocks of Portland limestone, Cornish granite and marine concrete were attached to shore platforms in Cornwall, UK, at Mean Tide Level. After 8 months exposure, Water Absorption Capacity (WAC) was determined (in both fresh water and synthetic seawater) for exposed and control samples, and strength was measured using Point Load and Equotip surface hardness tests. Differences between exposed and control samples were examined with ANOVA, using material type (3 levels; limestone, granite and concrete) and treatment (2 levels; control and field exposed) as fixed factors. There were significant differences in the WAC of field exposed materials compared to unexposed controls after 8 months (p = 0.02). Post-hoc Student Newman Kuels (SNK) tests also revealed significant material x treatment combinations in both fresh and synthetic seawater (p < 0.01). Field exposed concrete had lower water absorption compared to controls (p < 0.05), which was associated with the development of a surface bio-chemical crust (observed using SEM) and an increase in surface hardness (Equotip test, Student's t-test p = 0.05). In contrast, WAC of limestone in fresh and synthetic seawater was higher for exposed samples compared to controls, but was only significant in fresh water (p = 0.05). SEM examination suggests that extensive borehole erosion of exposed limestone probably explains these differences. Surface hardness of exposed limestone was lower than controls, which may also be associated with boring activity, but this was not statistically significant after 8 months. Water Absorption Capacity and surface hardness were no different between controls and field exposed granite samples. Point Load tests showed no detectable changes in bulk material strength of any material after 8 months exposure. Results are discussed with respect to early-stage physical changes of natural rock and artificial materials exposed in the intertidal zone during the construction of hard coastal defences. In particular, the role of material composition in determining responses to exposure, and temporal changes in the susceptibility of natural rock and concrete to different intertidal weathering and erosion processes, are discussed.

Coombes, Martin A.; Naylor, Larissa A.; Feal-Pérez, Alejandra

2010-05-01

112

Schmidt Hammer studies in the maritime Antarctic: Application to dating Holocene deglaciation and estimating the effects of macrolichens on rock weathering  

NASA Astrophysics Data System (ADS)

In order to contribute to the reconstruction of the deglaciation history of the Marguerite Bay area (~ 68°S, Maritime Antarctic) and to estimate the rock weathering rate in this Antarctic sector, 28 sites (7 on Rothera Point and 21 on Anchorage Island) were characterised using Schmidt Hammer values. The weathering effect of two of the most widespread species of macrolichens in this area (Usnea sphacelata and Umbilicaria decussata) was tested at 5 different sites on Rothera Point.Schmidt Hammer data, in conjunction with recent 14C age, suggest a deglaciation age for the Marguerite Bay area of around 12 ka, and an average uplift rate of 5.4 mm year- 1 on Anchorage Island for the period between 3.3 and 5.2 ka. The weathering rates are extremely slow (e.g. three times slower than reported in Norway). Our data confirm that lichens exert a strong impact on weathering, decreasing the Schmidt Hammer R-values on lichenised surfaces by a factor of 3-4 compared to bare rock surfaces. The effect of lichens on weathering is mainly due to edaphic conditions and the type of the lichen involved rather the period of exposure.

Guglielmin, M.; Worland, M. R.; Convey, P.; Cannone, N.

2012-06-01

113

Characterization and petrophysical properties of hydrothemally altered lacustrine volcanistic rock in Geyser Valley (Kamchatka) and its transformation by weathering  

NASA Astrophysics Data System (ADS)

Work is devoted to the study of volcano sedimentary hydrothermally altered rocks in Geyser Valley (Kamchatka peninsula, Russia). The Geyser Valley is one of the most unique nature objects in Russia. There are quite large geyser fields. The valley of the river is part of the Uson-Geysernaya depression, where hydrothermal activity is very high. Besides geysers here are hot springs, mud pots and fumarols. In the late Pleistocene (about 45-35 thousand years ago) the lake was located in the site of the modern valley of the Geysernaya river, where sediments accumulated intensively. Sedimentary material came from several sources in the form of pyroclastic flows, ash falls, was supplied by permanent and temporary water streams. The total deposit thickness reached several hundred meters. In the late Pleistocene there was breakthrough of reservoir and further conditions for the lacustrine deposits formation did not arose. Later the rocks were intensively processed by thermal water. In 2007 large landslide was formed in lower part of the Geysernaya River on their left slope. Deposits of Geysernaya (Q34grn) series and Pemsovaya (Q34pmz) series were involved in landslide displacement. The headscarp was formed up to 100 m and a length of 800 m, exposing the volcano-sedimentary section of hydrothermally altered rocks - a unique opportunity for sampling and subsequent laboratory study. Thickness of lake sediments is interbedding of coarse-grain, medium-grain, fine-grain tuffites predominantly acidic composition. The study of thin sections revealed that all samples are lithoclastic and vitroclastic hydrothermally altered tuffits. Currently, the primary minerals and volcanic glass is largely replaced by clay minerals of the smectite group. Pores and cracks are made zeolites (heulandite and clinoptilolite). All this points to the low-temperature (<200 ° C) hydrothermal conditions with a pH near neutral. Tyere are acid plagioclase and quartz in most samples The high content of smectite causes high hygroscopy of deposits. Rocks are highly porous - of 37-65%, primarily low density - 0,9-1,65 g/cm3 wave velocities - from 0.74 km/s for porous to 3.42 km/sec for dense varieties. All samples are characterized by low strength characteristics: uniaxial compressive strength - 1.2 - 21.7 MPa, uniaxial tension - 0,6-4,7 MPa. By water saturation strength decreases rapidly. Soft coefficient ranges from 0.22 to 0.57. Proving to be on the land surface as a result of slope deformation, volcanic-sedimentary hydrothermally altered rocks are destroyed quickly by precipitation and temperature fluctuations Rock turned to sand, silt and clay depending on the original composition. It was found that often weathered to clayey state tuffites inherit structural and textural features of the primary species. The composition also varies: increased content of clay minerals (to 90%), decreasing the content of zeolites (not to exceed 10%). Quartz and plagioclase form sans fraction. Physical and mechanical properties vary widely: the density of the soil increases slightly up to 1,57-1,59 g/cm3 for sands, 1,2-1,79 g/cm3 for clays, porosity of 51-52% and 49-78% respectively, moisture 22-23% and 43-98/ Clays are in a state of semi-solid to fluid. The high content of smectite determines high plastic properties. Plasticity Index varies widely from 11 to 57. Cohesion and the internal friction angle obtained from shear tests also change widely. For clayey sand grip reaches 137 kPa, internal friction angle - 17 degrees. In clay grip ranges from 13 kPa to 120 kPa, and the internal friction angle - from 11 degrees to 31 degrees. Large variation of properties of the investigated soils is explained by the inhomogeneity of volcano-sedimentary formations both vertically and laterally, varying degrees of hydrothermal alteration and of weathering, fracturing and cracks filling The obtained datas can adequately characterize the volcanic-lacustrine sediments in the valley of the Geysernaya river and use them in calculations of slope stability and for and geological mapping.

Gvozdeva, Irina; Zerkal, Oleg; Samarin, Evgeny

2013-04-01

114

Rocks  

NSDL National Science Digital Library

In this activity students will use sample sets of igneous, metamorphic, and sedimentary rocks to learn how to identify the major rock types. They will write the key characteristics that would help them identify each of the rocks on the list. They will find and copy an image of each from the "Volcano World" slide show and answer the questions at the end of this activity. As a result of this lesson students will learn how to identify major rock types through their characteristic properties, especially through the Earth Science Reference Table identification charts, and understand how to find out what types of rocks can be found in a particular area using geologic maps, especially the one in the Earth Science Reference Table.

Lamont-Doherty Earth Observatory, The E.

115

Slope processes in weathered volcaniclastic rocks of the Camaldoli hill (Naples, Italy): Geomorphologic and Engineering-Geological aspects  

NASA Astrophysics Data System (ADS)

Following the geological study performed by Orsi et al. (this session), the main results of a geomorphologic and engineering-geological investigation of the stability conditions of the Camaldoli hill (urban area of Naples) are here presented. The Camaldoli hill, the highest peak of the Phlegraean Fields caldera (452 m asl), is characterized by relief energy of a few hundreds of meters, and by high slope gradients, which frequently reach the verticality. Low-order, structurally controlled channels drain the hillslopes; the development of stepped longitudinal profiles in the channels is related to the alternance of rocks and soils. The geological framework of the hill represent a further factor predisposing to mass movements and soil erosion. The Camaldoli hill is in fact characterized, as already highlighted by Orsi et al., by a basal sequence of jointed weak tuffs, overlain by some tens of metres of loose, unconsolidated pyroclastic terrains, ranging in age from about 12.000 and 4.000 yrs. BP. The latter deposits are generally weathered in their upper layers, as a consequence of interaction with decay agents and of past slope instabilities. Present-day morphodynamics of the hill is ruled by the occurrence of a variety of slope processes. Shallow landslides involve the weathered portion of the youngest pyroclastic products, showing features typical of slides or falls. Such events, which usually start in the upper reaches of the slope, may undergo different evolution, essentially controlled by the local slope morphology: (i) low-mobility soil slides-debris flows on open slopes; (ii) slides/falls evolving to hyperconcentrated flows along channels. The first processes have been seldom observed on open slopes, while the transition from slides/falls to hyperconcentrated flows along channels seems much more diffuse in the study area. The flows are generally fed, under intense to extreme rainfall events, by the re-mobilization of pre-existing landslide debris. The upper tuff formations (namely, the Neapolitan Yellow Tuff) are involved in falls and topple failures, which can detach volumes up to some tens of cubic metres, frequently reaching the lowest sectors of the slope, close to, if not within, the urbanized area. Eventually, accelerated soil erosion plays a major role in the open slopes, where evidences of sheet, rills and gullies have been surveyed. Joining the contribution of volcanologists and engineering-geologists, a tentative evaluation of the volumes susceptible to be mobilized by instability processes acting on the surficial, weathered cover of the loose pyroclastics was performed, adopting different methodologies. The so obtained results are compared and discussed in the paper: overall, they provide evidence of a widespread proneness to slope instability, which in turn may result into a serious threat to the diffuse settlements and infrastructures located at the Camaldoli’s foothill.

Calcaterra, D.; Coppin, D.; Palma, B.; Parise, M.; Orsi, G.; de Vita, S.; di Vito, M. A.

2003-04-01

116

Gravestone Weathering  

NSDL National Science Digital Library

In this activity (located on pages 9-14 of PDF), learners visit a cemetery to examine the distinguishing characteristics of rock weathering. After researching stone weathering and acid rain, learners apply their knowledge to collect data related to chemical decomposition and physical disintegration at a cemetery site. This detailed lesson guide includes tips for educators, pre/post activity suggestions, hands-outs, and background information.

Wiberg, Leanne; History, National M.

2000-01-01

117

Rates of Chemical Weathering  

NSDL National Science Digital Library

In this activity, students will investigate the weathering of rocks by chemical processes. They will use effervescent cleansing tablets as a model for rock, and vary surface area, temperature, and acidity to see how rapidly the "rock" dissolves. This investigation will help them understand three of the factors that affect the rate of chemical weathering and develop better understanding of how to design controlled experiments by exploring only one experimental variable at a time.

Passow, Michael

118

Chemical weathering of silicate rocks in Karelia region and Kola peninsula, NW Russia: Assessing the effect of rock composition, wetlands and vegetation  

Microsoft Academic Search

This study is aimed at assessing the effect of factors including lithology, forest\\/peatland coverage, dissolved organic carbon, and vegetation on chemical fluxes and concentrations of major elements in rivers. The mean annual element concentrations and dissolved fluxes of acid and basic rock dominated watersheds of the Karelia region and Kola peninsula, NW Russia, have been estimated from the chemical composition

E. A. Zakharova; O. S. Pokrovsky; B. Dupré; J. Gaillardet; L. E. Efimova

2007-01-01

119

Structure and chemistry of bacterially populated acidic microenvironments found on naturally colonized and weathered circumneutral pH unsaturated waste rock from the Antamina Mine, Peru  

NASA Astrophysics Data System (ADS)

The microbial community present in geochemically well characterized field cells and experimental waste rock piles at the Antamina Mine, were examined using electron microscopy, culture dependent, and culture independent techniques. Relatively large populations of up to 10^8 bacteria per gram were found, despite the young age of the waste rock (1.5 years). Most samples were at alkaline pH and dominated by bacteria capable of neutral pH thiosulfate oxidation. One sample from a field cell producing drainage at a pH of 6.5 was dominated by acidophilic bacteria capable of Fe^2+ and S^0 oxidation. A weathered massive sulfide from this sample was thoroughly examined using a field emission gun scanning electron microscope equipped with a focused ion beam (FE-SEM-FIB). Bacteria were abundant as monolayer and agglomerate biofilms upon and within a porous schwertmannite precipitate, while no bacteria were found directly attached to clean sulfide surfaces. Pitting of pyrrhotite was observed beneath the microbially inhabited schwertmannite, while no pitting was observed in adjacent clean pyrrhotite surfaces indicating greater oxidation of the pyrrhotite surface beneath the schwertmannite. Some waste rock that has been exposed to natural surface weathering conditions for more than twice the amount of time, possessed larger total populations of bacteria, but did not support significant populations of acidophiles, suggesting a succession from neutrophiles to acidophiles takes place prior to the development of acid mine drainage. The development of the porous iron oxide film may be prerequisite for acidophilic bacteria to flourish, creating acidic microenvironments within a neutral bulk, ambient pH mine waste.

Dockrey, J. W.; Mayer, K. U.; Beckie, R. D.; Southam, G.

2009-12-01

120

Rapid changes in the physical properties of rock and concrete during intertidal exposure; implications for weathering and engineering durability  

Microsoft Academic Search

Water absorption is an important parameter affecting the susceptibility of rocky shore substrates and construction materials to wetting-drying, salt weathering and dissolution processes exposed in the intertidal zone. Strength is also an important determinant of durability and resistance to erosion processes such as abrasion. Here we examine changes in the water absorption properties and strength of representative materials used in

Martin A. Coombes; Larissa A. Naylor; Alejandra Feal-Pérez

2010-01-01

121

Rare earth elements in stream waters from the Rokko granite area, Japan: Effect of weathering degree of watershed rocks  

Microsoft Academic Search

The concentrations of major elements and rare earth elements (REE) of the stream waters from the Rokko granite area, Japan, were analyzed to examine the relationship between the degree of weathering and chemistry of the waters. The clay minerals in the related soils from the watershed areas were also examined. It was found that the relative proportion of kaolinite to

TAIGA NAKAJIMA; YASUTAKA TERAKADO

122

Silica- and sulfate-bearing rock coatings in smelter areas: Products of chemical weathering and atmospheric pollution I. Formation and mineralogical composition  

NASA Astrophysics Data System (ADS)

Black rock-coatings occur in proximity to smelters and roast yards of the Greater Sudbury area, Ontario, Canada and contain information about the past interactions between surface minerals, and gaseous and particulate atmospheric components, many of which were pollutants. Rock-coatings were collected from various locations within the Sudbury area and are characterized with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, electron microprobe analysis, infrared spectroscopy and X-ray photoelectron spectroscopy. Acidic fumigations and rain, the result of vast quantities of SO2 released from smelting, increased the chemical weathering rate of exposed rocks in the Sudbury area. Non-stoichiometric dissolution of the silicate minerals under acidic conditions resulted in the accumulation of silicic acid and the subsequent formation of a silica-gel type coating. The silica gel transformed overtime into amorphous silica, opal (opal C and opal-CT) and cristobalite. Dissolution of the underlying rock and also of metal-bearing particles by sulfuric acid resulted in the in situ formation of metal-sulfate-rich layers on the interfaces between the atmosphere and the silica-rich coating (atmosphere-coating interface, ACI) and between the silica-rich coating and the underlying rock (rock-coating interface, RCI). These metal-sulfate-rich layers contain nanometer aggregates of Fe-Cu-sulfate-hydroxide, goldichite, mereiterite, guildite, butlerite and antlerite. The silica-rich matrix also contains a mix of detrital grains from adjacent rocks and soils (feldspar, quartz, hematite, chlorite, montmorillonite) and non-dissolved smelter-derived nano- to micro-size particulates (metal-silicates, metal-oxides, C-spheres). The apparent disequilibrium between the embedded particles and the Fe-Cu-sulfates suggests that trapped nanoparticles were encapsulated into pores which prevented their equilibration with acidic metal-sulfate-bearing fluids. An XPS depth profile indicates a gradual transition from lower to higher concentrations of metals from the coating surface towards the metal-sulfate-rich layer on the ACI, which suggests that the outer surface of the coatings is currently leached on an angstrom scale by surface waters.

Mantha, Nathalie M.; Schindler, Michael; Murayama, Mitsuhiro; Hochella, Michael F.

2012-05-01

123

Rare earth element trends and cerium-uranium-manganese associations in weathered rock from Koongarra, Northern Territory, Australia  

Microsoft Academic Search

At Koongarra, Australia, three drill cores from the Cahill Schist Formation containing U-ore, and regolith above it containing secondary U-ore, were studied to ascertain the distribution of rare earth elements (REEs) and U. The unaltered schist has a REE trend similar to the Post Archaean Australian Shale (PAAS), which is, therefore, used as a normalising standard. Unweathered rock from the

Anthony J. Koppi; Robert Edis; Damien J. Field; Harold R. Geering; David A. Klessa; David J. H. Cockayne

1996-01-01

124

Effects of direct and indirect heating on the validity of rock weathering simulation studies and durability tests  

Microsoft Academic Search

Rock surface and subsurface temperature responses in samples exposed to direct heating (insolation) under natural hot desert conditions reveal considerable variability between lithologies related to differences in thermal properties, especially albedo and thermal conductivity. However, when the same samples are heated indirectly by air in an oven-based environmental cabinet, lithological differences in temperature response disappear and all samples attain temperatures

P. A. Warke; B. J. Smith

1998-01-01

125

Temporal trends of dissolved weathering products released from a high Arctic coal mine waste rock pile in Svalbard (78°N)  

Microsoft Academic Search

It is well known that oxidation of sulphide-containing coal mine waste has considerable environmental impacts due to generation of acid mine drainage (AMD) containing high dissolved metal concentrations. This study is the first to evaluate seasonal trends in the release of AMD from high arctic coal mine waste rock. Runoff from an abandoned coal mine waste pile in Svalbard (78°N)

Jens Søndergaard; Bo Elberling; Gert Asmund; Claus Gudum; Karl Martin Iversen

2007-01-01

126

Pathways of calcrete development on weathered silicate rocks in Tamil Nadu, India: Mineralogy, chemistry and paleoenvironmental implications  

NASA Astrophysics Data System (ADS)

Poorly documented yet spectacularly thick and extensive outcrops of calcrete hardpan occur on gneiss in the semiarid region of Coimbatore, South India. The hardpan caps a series of residual plateaux forming the present-day continental divide and grades into large expanses of Vertisols. Characteristic calcrete and Vertisol profiles were logged along toposequences and sampled for macro- and micromorphological study, and for chemical and mineralogical composition. Strontium isotopic analyses revealed that the calcrete is derived from in situ weathering of Ca-bearing primary minerals of the saprolite, which is rich in ankerite, Ca-amphiboles and Ca-plagioclase. The macroscale analysis revealed a range of facies developed within the gneiss saprolite, but in terms of relative chronology the nodular hardpan has the longest history. Two evolutionary pathways leading to nodular hardpan formation have been established. The first occurs entirely within a vadose environment, whereas the second begins within a phreatic environment before continuing to develop in vadose conditions. The ability to identify and map these generic categories of calcrete constitutes a potential tool for reconstructing paleotopography and paleogroundwater levels. The bedrock-weathering-derived nodular hardpan is blanketed by a laminar facies that correlates with an eolian event with marine Sr signatures. This suggests influx of Ca dust from the Arabian Sea continental shelf during a Pleistocene sea-level low-stand. It defines an important benchmark in the chronology of the area and highlights the potential antiquity of the thick calcrete profiles.

Durand, N.; Gunnell, Y.; Curmi, P.; Ahmad, S. M.

2006-11-01

127

Do Rocks Last Forever?  

NSDL National Science Digital Library

In this activity, students learn about chemical and mechanical weathering in rocks. From the background material, they will learn that the change that takes place in rocks is called weathering and that this term refers to the destructive processes that change the character of rock at or near the Earth's surface. Processes of mechanical weathering (or physical disintegration) break rock into smaller pieces but do not change its chemical composition; processes of chemical weathering (or rock decomposition) transform rocks and minerals exposed to water and atmospheric gases into new chemical compounds (different rocks and minerals), some of which can be dissolved away. Four experiments that illustrate the effects of mechanical and chemical weathering are provided.

128

Impact of weathering on the geomechanical properties of rocks along thermal metamorphic contact belts and morpho-evolutionary processes: The deep-seated gravitational slope deformations of Mt. Granieri Salincriti (Calabria Italy)  

NASA Astrophysics Data System (ADS)

Numerous Deep-Seated Gravitational Slope Deformations (DSGSDs) occur throughout Italy, that originate from particular tectono-stratigraphic settings, relief, seismicity, deglaciation, as well as from intense and deep processes of chemico-physical weathering of crystalline metamorphic rocks. These DSGSDs are particularly widespread in the Calabrian mountains. This study is focused on the Mt. Granieri Salincriti slope, on the Ionian side of the Serre Massif, where granites and granodiorites (Stilo Unit, Palaeozoic) are in contact with metamorphites through a thermal metamorphic aureole. This setting generates deep geochemical processes, inducing intense chemical weathering. These processes are mainly due to the interaction between groundwater and the sulphides that are contained in the local pegmatitic hydrothermal intrusions, especially along the thermal metamorphic contact belt. The Mt. Granieri Salincriti slope has an important DSGSD, which is associated with many active and/or quiescent landslides. Among these landslides, the Salincriti rock avalanche-debris flow (about 2 M m3) represents the paroxysmal and terminal stage of the deep creep deformations of Mt. Granieri, typifying a geological setting that is common in the Calabrian Arc. This multi-disciplinary study assessed the weathering susceptibility of the local crystalline metamorphic rocks, especially those lying along thermal metamorphic contact belts, by characterising the weathering horizons and the spatial distribution of weathering in the rock mass. The study was also aimed at identifying the relations between weathering, above all deep geochemical processes, effects on rocks and slope morphodynamics. The methodology was based on detailed geological data, geological engineering surveys, geomorphology and surface hydrogeology analyses, as well as physico-mechanical laboratory tests. These investigations, supported by a monitoring program, led to the development of an engineering geological model of the slope. Geological character (attributed to a thermal metamorphic contact belt), geomorphological evidence and geomechanical elements elucidated the interactions between deep geochemical processes and weak belts in the investigated rocks, as well as the critical role that these interactions play in the evolution of deep-seated creep deformations and associated shallow landslides.

Pellegrino, A.; Prestininzi, A.

2007-06-01

129

Quantification of physical weathering rates using thermodynamics  

Microsoft Academic Search

Physical weathering plays an important role in the global rock cycle in that it breaks up primary rock, thereby increasing the surface area for chemical weathering and providing the substrate for soil formation. We use a simple, thermodynamics based approach to quantify magnitudes of weathering, their spatial variation across climatic regions and their sensitivity to climatic change. Our approach is

F. Gans; S. Arens; S. J. Schymanski; A. Kleidon

2010-01-01

130

Natural Weathering Rates of Silicate Minerals  

Microsoft Academic Search

Silicates constitute more than 90% of the rocks exposed at Earth's land surface (Garrels and Mackenzie, 1971). Most primary minerals comprising these rocks are thermodynamically unstable at surface pressure\\/temperature conditions and are therefore susceptible to chemical weathering. Such weathering has long been of interest in the natural sciences. Hartt (1853) correctly attributed chemical weathering to \\

A. F. White

2003-01-01

131

Impact of weathering on the geomechanical properties of rocks along thermal–metamorphic contact belts and morpho-evolutionary processes: The deep-seated gravitational slope deformations of Mt. Granieri–Salincriti (Calabria– Italy)  

Microsoft Academic Search

Numerous Deep-Seated Gravitational Slope Deformations (DSGSDs) occur throughout Italy, that originate from particular tectono-stratigraphic settings, relief, seismicity, deglaciation, as well as from intense and deep processes of chemico-physical weathering of crystalline–metamorphic rocks. These DSGSDs are particularly widespread in the Calabrian mountains. This study is focused on the Mt. Granieri–Salincriti slope, on the Ionian side of the Serre Massif, where granites

A. Pellegrino; A. Prestininzi

2007-01-01

132

Yellowstone Weather  

NSDL National Science Digital Library

Yellowstone National Park's high altitude and mountainous terrain makes weather prediction very difficult. This website provides seasonal weather information, average temperature and precipitation data, links to weather forecasts, and other weather links.

Park, Yellowstone N.

133

Rock Cycle Animation  

NSDL National Science Digital Library

The rock cycle is an ongoing process in which rock, driven by tectonic processes such as volcanoes and earthquakes, the surface processes of weathering and erosion, and compaction, is created, destroyed, and recycled. This interactive feature introduces viewers to the processes which come into play as rock proceeds through the various portions of the cycle.

2011-06-22

134

Rock weathering and Carbon cycle  

Microsoft Academic Search

In the history of the Earth system, we can find indicators of hot or glacial periods, as well as brutal climatic change... How can we explain those climate variations on a geological timescale ? One of the causative agents is probably the fluctuation of atmospheric CO2 amounts, (gas responsible for the greenhouse effect). A concrete study of some CO2 fluxes

Patrick Strozza

2010-01-01

135

Honeycomb Weathering of Limestone Formations  

USGS Multimedia Gallery

Honeycomb weathering of sandstone located on the shores of Puget Sound occurs when expanding salt crystals break fragments of rock, creating a small hole that becomes larger as the process repeats itself over time....

2010-08-16

136

Weathering of Rocks in Gusev Crater Inferred From Correlations Between Primary and Secondary Fe-bearing Minerals Identified by Spirit's Moessbauer Spectrometer  

NASA Astrophysics Data System (ADS)

The Mars Exploration Rover Spirit has by now identified more than six different rock classes during its traverse from the landing site across the plains and into the Columbia Hills. The classification is based on the rocks' chemical composition, and can be further divided into several subclasses on the basis of mineralogical composition from Moessbauer spectra. Rocks in Gusev Crater show various degrees of alteration, both between different rock classes and within individual rock classes. Fe3+/FeTotal ratios determined by Moessbauer spectroscopy were used as a measure of the alteration of individual rocks. Spirit's Moessbauer spectrometer identified eight different Fe-bearing mineral phases: The primary minerals olivine, pyroxene, ilmenite, and magnetite as well as the secondary minerals hematite, goethite, an unspecified nanophase ferric oxide phase, and a ferric sulfate. For all rock and soil targets the amounts of Fe in individual primary minerals were plotted against Fe3+/FeTotal ratios, and the amounts of Fe in individual secondary minerals. A good correlation is observed between olivine and Fe3+/FeTotal in all rock and soil classes, whereas a good correlation between pyroxene and Fe3+/FeTotal is only observed in pervasively altered rocks in the Columbia Hills. Ilmenite and magnetite show no apparent correlation with Fe3+/FeTotal ratios. Plots between primary and secondary minerals indicate that Fe from olivine or pyroxene is altered to a range of secondary phases rather than one individual secondary mineral. However, remarkable correlations exist between olivine and hematite in Pot of Gold Class rocks and between magnetite and goethite in Clovis Class rocks. The results suggest that the slow alteration of olivine in rocks and soils is the only currently active alteration process in Gusev Crater.

Schroeder, C.; Klingelhoefer, G.; Morris, R. V.; Rodionov, D. S.

2006-12-01

137

Weather Watch  

ERIC Educational Resources Information Center

Suggests a number of ways in which Federal Aviation Agency weather report printouts can be used in teaching the weather section of meteorology. These weather sequence reports can be obtained free of charge at most major airports. (JR)

Bratt, Herschell Marvin

1973-01-01

138

Natural building stones of Mexico–Tenochtitlán: their use, weathering and rock properties at the Templo Mayor, Palace Heras Soto and the Metropolitan Cathedral  

Microsoft Academic Search

In the Aztec period and in colonial times different natural stones originating in the Valley of Mexico were used for building\\u000a construction. Stone weathering was investigated onsite at various historical buildings within the old quarter of Mexico City.\\u000a In this study, different aspects of weathering and deterioration at three significant historical buildings will be presented,\\u000a the Aztec excavation site Templo

Wanja Wedekind; Joerg Ruedrich; Siegfried Siegesmund

2011-01-01

139

Severe Weather  

ERIC Educational Resources Information Center

Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This month's insert, Severe Weather, has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in this poster are hurricanes,…

Forde, Evan B.

2004-01-01

140

Weather Forecasting  

NSDL National Science Digital Library

Students consider how weather forecasting plays an important part in their daily lives. They learn about the history of weather forecasting â from old weather proverbs to modern forecasting equipment â and how improvements in weather technology have saved lives by providing advance warning of natural hazards.

Integrated Teaching And Learning Program

141

Severe Weather  

ERIC Educational Resources Information Center

Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This article deals with a poster entitled, "Severe Weather," that has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in…

Forde, Evan B.

2004-01-01

142

Severe Weather  

ERIC Educational Resources Information Center

|Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This month's insert, Severe Weather, has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted in this poster are hurricanes,…

Forde, Evan B.

2004-01-01

143

Severe Weather  

ERIC Educational Resources Information Center

|Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. This article deals with a poster entitled, "Severe Weather," that has been created by NOAA to help educate the public about hazardous weather conditions. The four types of severe weather highlighted…

Forde, Evan B.

2004-01-01

144

UM Weather  

NSDL National Science Digital Library

Sponsored by The Weather Underground at the University of Michigan at Ann Arbor, UM Weather bills itself as the "Internet's premier source of weather information." The site offers several general audience tools such as the Fast Forecast for any city in the US, ski weather, and weather cams. But, it also provides access to over two dozen weather software packages, a new computer model forecasts page, and most impressively a list of close to 400 other weather related Web sites. Professionals and researchers will appreciate the non-technical feel of the site and the valuable information they can procure from it.

1994-01-01

145

Weather Predictions  

NSDL National Science Digital Library

Students will use the internet to learn about weather and play games enhancing their knowledge and interest. Using the knowledge they learned students will write out their prediction of their next 5 days of weather. Intro Task Resources Evaluation Conclusion Teacher Guide Intro Look at the current weather forecast-Click here Current Weather-CNN Task Search for information about what causes different kinds of weather and what instruments people use to predict weather. What is a person called who predicts weather? Resources Resource 1 Resource 2 Resource 3 Resource 4 Resource 5 Resource 6 Evaluation Rubric Conclusion After researching, create your ...

Burr, Miss

2009-03-27

146

Groundwater in granitic rocks  

Microsoft Academic Search

A comparison of published chemical analyses of ground waters found in granitic rocks from a variety of locations shows that their compositions fall into two distinct classes. Ground waters from shallow wells and springs have a high bicarbonate\\/chloride ratio resulting from the neutralization of carbonic acid (dissolved COâ) by weathering reactions. The sodium, potassium, and silica released by weathering reactions

Rimstidt

1985-01-01

147

Thermal behaviour of weathered and consolidated marbles  

Microsoft Academic Search

To optimise stone consolidation it is necessary to understand the mechanisms of weathering in marbles, the control by the mineralogical composition and the rock fabric. The knowledge of how the stone consolidants affect the weathering mechanisms and if they are compatible with the stone is also an important consideration. The weathering of marble can begin with thermal stress whereby cracks

J. Ruedrich; T. Weiss; S. Siegesmund; E. K. Tschegg

2003-01-01

148

Rivers, chemical weathering and Earth's climate  

Microsoft Academic Search

We detail the results of recent studies describing and quantifying the large-scale chemical weathering of the main types of continental silicate rocks: granites and basalts. These studies aim at establishing chemical weathering laws for these two lithologies, describing the dependence of chemical weathering on environmental parameters, such as climate and mechanical erosion. As shown within this contribution, such mathematical laws

Bernard Dupré; Céline Dessert; Priscia Oliva; Yves Goddéris; Jérôme Viers; Louis François; Romain Millot; Jérôme Gaillardet

2003-01-01

149

Weather & Weather Maps. Teacher's Manual.  

ERIC Educational Resources Information Center

This guide is intended to provide an opportunity for students to work with weather symbols used for reporting weather. Also included are exercises in location of United States cities by latitude and longitude, measurement of distances in miles and kilometers, and prediction of weather associated with various types of weather fronts. (RE)

Metro, Peter M.; Green, Rachel E.

150

Dissolution of olivine during natural weathering  

NASA Astrophysics Data System (ADS)

Naturally weathered olivine occurring as phenocrysts in Hawai'ian volcanic rocks from several volcanic centers and regolith/outcrop settings, and as tectonized olivines from several metadunite bodies in the southern Appalachian Blue Ridge, are all similarly corroded by natural weathering. Conical (funnel-shaped) etch pits occur as individual pits, base-to-base pairs of cone-shaped pits, or en echelon arrays. Etch-pit shapes and orientations in the smallest etch-pit arrays visible in conventional scanning electron microscopy resemble even smaller features previously reported from transmission electron microscope investigations of olivine weathering. Etch pits occur in samples with chemical and/or mineralogical evidence of weathering, and/or are associated with, or proximal or directly connected to, fractures or exposed outcrop surface, and therefore are formed by weathering and not inherited from pre-weathering aqueous alteration (e.g., serpentinization, iddingsitization) of these parent rocks. Many etch pits are devoid of weathering products. Natural weathering of olivine is surface-reaction-limited. Similarity of corrosion forms from naturally weathered olivine from multiple igneous and metamorphic parent-rock bodies suggests that olivine weathers in the same manner regardless of its specific crystallization/recrystallization history, eruption/weathering/exposure ages of the olivine's host rock, and the local regolith history.

Velbel, Michael A.

2009-10-01

151

Weather Watchers  

NSDL National Science Digital Library

In this lesson, students learn how meteorologists measure the weather by examining some online, real-time data resources and collaborating to create an in-class weather station that tracks local weather patterns for one week. Students compare this information to weather patterns in two other locations. After completing this lesson, students should be able to explain ways that meteorologists measure and predict weather and use the Internet to research information about weather conditions in various locations in the United States, including their hometown. Students will also collaborate on creating some weather-measurement instruments and keep a weather journal for one week. This site provides an overview of the lesson, detailed procedures for the teacher, including a list of research sites, and an organizational path for students.

152

Weather Talk  

NSDL National Science Digital Library

Weather Talk is a primer on weather and naval meteorology. It provides a brief overview of major weather elements and is presented in a non-mathematical way, so that the reader will have a better understanding of the basic mechanisms of weather and use it to their advantage and safety in planning and carrying out their own activities. The site explains temperature, wind, pressure, atmospheric moisture, air masses and fronts, thunderstorms, tornadoes, hurricanes, and climatology.

153

Chemical weathering of silicate rocks in Aldan Shield and Baikal Uplift: insights from long-term seasonal measurements of solute fluxes in rivers  

Microsoft Academic Search

A reassessment of available information from the Russian Hydrological Survey on long-term seasonal measurements of water, suspended matter and dissolved major element discharges in ?30 small and large watersheds draining acid silicate rocks (granites, gneisses, quartzites, shales) of the Aldan Shield and Baikal Uplift was combined with new data on river water chemistry for three granitic watersheds in order to

E. A. Zakharova; O. S. Pokrovsky; B. Dupré; M. B. Zaslavskaya

2005-01-01

154

An Experimental Study of Rock Dissolution Kinetics and Implications On Weathering Rates In An Active Volcanic Area: The Case Study of Mount Etna  

Microsoft Academic Search

Six dissolution experiments were performed on fresh and undisturbed basaltic rock samples (hawaiite), that were collected from two quarries in the Mount Etna area. They can be attributed to the well documented historical 1669 lava flow. Different operating conditions were selected to carry out the experiments, with the aim of quan- tifying the role of chemico-physical parameters on dissolution, such

B. Parisi; F. Parello; M. Valenza

2002-01-01

155

Antarctic Weather  

NSDL National Science Digital Library

Visitors to this site can read a discussion about the weather in Anarctica, including why it is so cold, how weather observations are conducted there, and what role the continent plays in the global weather system. Links to related topics, a wind chill calculator, and a Fahrenheit-Celsius-Kelvin temperature converter are also provided.

156

Severe Weather  

NSDL National Science Digital Library

Educating the public about safety issues related to severe weather is part of the National Oceanic and Atmospheric Administration's (NOAA) mission. The National Weather Service (NWS)--which is part of NOAA and its parent agency, the Department of Commerce--is charged with the critical responsibility of observing and reporting the weather and with issuing forecasts and warnings of weather and floods in the interest of national safety and economy. Through a massive network of weather-monitoring and reporting stations around the globe, including land, sea, air, and space-borne instruments, NWS scientists constantly assimilate all of the reliable weather data available. Much of this data are then used in numerical computer models of the atmosphere that help to accurately describe and interpret current conditions and produce the best possible forecasts of future weather.

Forde, Evan B.

2004-04-01

157

COSTRUZIONE DEL MODELLO GEOLOGICO-TECNICO IN AMMASSI CRISTALLINO- METAMORFICI AFFETTI DA INTENSI PROCESSI DI ALTERAZIONE: UN ESEMPIO DI APPLICAZIONE NEI BACINI DELLE F.RE ALLARO ED AMUSA (MASSICCIO DELLE SERRE, CALABRIA) CONSTRUCTION OF ENGINEERING-GEOLOGY MODEL OF CRYSTALLINE METAMORPHIC ROCK MASSES EXPERIENCING DEEP WEATHERING PROCESSES: EXAMPLE OF APPLICATION TO THE ALLARO AND AMUSA RIVER BASIN (SERRE MASSIF, CALABRIA, ITALY)  

Microsoft Academic Search

The study of natural slope morphodynamic represents a com- plex topic involving many different features, among which geo- logical and structural settings, kinds of landform and process activity, groundwater seepage, climatic conditions and rheological behaviour of involved rock masses also related to weathering processes. Paper deals with an area located in the south-east side of Calabria (Serre Massif); in an

ANNAMARIA PELLEGRINO; ALBERTO PRESTININZI; GABRIELE SCARASCIA MUGNOZZA

2008-01-01

158

Evolution of porosity and diffusivity associated with chemical weathering of a basalt clast  

Microsoft Academic Search

Weathering of rocks as a result of exposure to water and the atmosphere can cause significant changes in their chemistry and porosity. In low-porosity rocks, such as basalts, changes in porosity, resulting from chemical weathering, are likely to modify the rock's effective diffusivity and permeability, affecting the rate of solute transport and thus potentially the rate of overall weathering to

Alexis Navarre-Sitchler; Carl I. Steefel; Li Yang; Liviu Tomutsa; Susan L. Brantley

2009-01-01

159

The assessment of weathering stages in granites using an EC\\/pH meter  

Microsoft Academic Search

The weathering of granite encompasses a wide range extending from slightly weathered rock to saprolite to soil. Although many different methods are available for quantifying the amount of chemical or physical weathering in granites, dissolution rate as a method for estimating the degree of chemical weathering in these rocks was not thoroughly investigated. This study sought to identify a method

Anestoria Shalkowski; Yoshinori Kodama; Shigenori Nakano

2009-01-01

160

Xenotime-hematite aggregates on opaline filaments: evidence for biomineralization in weathered siliciclastic rocks, Capanema, Quadrilátero Ferrífero of Minas Gerais, Brazil  

NASA Astrophysics Data System (ADS)

Dissolution cavities in weathered pebbly quartzite of the ~2.5-Ga Moeda Formation at Capanema, Quadrilátero Ferrífero of Minas Gerais, Brazil, are decorated with suspended filaments of opaline silica. The filaments sustain xenotime-hematite aggregates in the open space. Xenotime occurs as inclusions in buds and botryoidal aggregates of hematite. The filamentous structures consist of strand-forming buds, hypha-like extensions, and thin strands that compose mat-like arrangements. They resemble microbial filaments that were replaced by opaline silica and fossilized. The occurrence of spherical hematite as protuberances on hematite-free opaline hyphae is interpreted as accretion of dissolved iron onto extracellular polymers. Phosphate sites in polymeric substances expelled from the microbial filaments might have adsorbed yttrium and heavy rare-earth elements from groundwater to the iron-accreting polymers. These would have resulted in botryoidal aggregates of hematite with xenotime inclusions. The presence of authigenic xenotime in the weathering zone opens a new possibility to constrain the evolution of lateritic profiles by xenotime geochronology.

Cabral, Alexandre Raphael; Koglin, Nikola; Seabra Gomes, Antônio Augusto; Lehmann, Bernd

2012-01-01

161

Weather Instruments  

NSDL National Science Digital Library

This Topic in Depth discusses the variety of instruments used to collect climate and weather data. The first two websites provide simple introductions to the many weather instruments. Bethune Academy's Weather Center (1) discusses the functions of psychrometers, anemometers, weather balloons, thermometers, and barometers. The Illinois State Water Survey (2) furnishes many images of various instruments that collect data daily for legal issues, farmers, educators, students, and researchers. The third website (3), created by the Center for Improving Engineering and Science Education (CIESE), provides a classroom activity to educate users on how to build and use weather instruments. By the end of the group project, students should know all about wind vanes, rain gauges, anemometers, and thermometers. Next, the Miami Museum of Science provides a variety of activities to help students learn about the many weather instruments including wind scales and wind chimes (4). Students can learn about the wind, air pressure, moisture, and temperature. At the fifth website, the Tyson Research Center at Washington University describes the devices it uses in its research (5). At the various links, users can find out the center's many projects that utilize meteorological data such as acid rain monitoring. The sixth website, a pdf document created by Dr. John Guyton at the Mississippi State University Extension Service, provides guidance to teachers about the education of weather patterns and instruments (6). Users can find helpful information on pressure systems, humidity, cloud patterns, and much more. Next, the University of Richmond discusses the tools meteorologists use to learn about the weather (7). While providing materials about the basic tools discussed in the other websites, this site also offers information about weather satellites, radar, and computer models. After discovering the many weather instruments, users can learn about weather data output and analysis at the Next Generation Weather Lab website (8). This expansive website provides an abundance of surface data and upper air data as well as satellite and radar images for the United States.

162

Weather Experiments  

NSDL National Science Digital Library

Looking for fun ways to learn about weather? Weather Wiz Kids has 39 fun weather related experiments for you to try. These experiments can be done in the classroom with your friends or even at home! Some of the experiments on the site include: tornado in a bottle, make lightning, make it rain, cloud in a bottle, what's in the wind, the Doppler Effect, and baking soda volcano.

2010-01-01

163

Weather Data  

NSDL National Science Digital Library

The listed websites are recommended safe kid friendly sites that may be used when gathering data for the at home data project. Use the websites listed to learn more about daily weather patterns in different cities around the world. After you have collected and organized your data, create a graph representing the different weather patterns in that city. Use this site to record the daily high temperature for your assigned city. The Weather Channel Use this ...

Harris, Ms.

2011-01-24

164

Spatial relationships of salt distribution and related physical changes of underlying rocks on naturally weathered sandstone exposures (Bohemian Switzerland National Park, Czech Republic)  

Microsoft Academic Search

Efflorescence, case hardening, and granular disintegration represent common weathering features of Upper Cretaceous quartz\\u000a sandstones exposed in the Bohemian Switzerland National Park (NW Bohemia, Czech Republic). Salt species (sulphates: gypsum\\u000a (CaSO42H2O), potassium alum (KAl(SO4)212H2O), tschermigite (NH4Al(SO4)212H2O), alunite (K(Al3(SO4)2(OH)6), and alunogen (Al2(SO4)317H2O), minor nitrates: nitrammite (NH4NO3)) determined by X-ray diffraction exhibit vertical and geographic zoning. More soluble salts (chlorides, nitrates, tschermigite)

R. P?ikryl; L. Melounová; Z. Va?ilová; Z. Weishauptová

2007-01-01

165

On the persistence of 'weathering'  

NASA Astrophysics Data System (ADS)

The term 'weathering' has been in use for a very long time but it has come to mean different things to different people and hence, as scientific short-hand, it no longer functions. Here we question the tenets underpinning the most common usage of the term and note that the climate-process linkage implicit to the term is often missing and amounts to misdirection. Rather than climate as the primary driver behind specific weathering processes, it is argued that rock properties constitute the dominant control. Further, a case is made for reconsideration of our present bipartite (mechanical/chemical) division of weathering processes and of the weathering processes currently deemed to be 'those that occur'. As process studies become evermore reductionist in nature, so the functionality of the term comes more and more into question. The linkage between process and landform, the scaling-up attribute, is seen as a current weakness and one that will become more confusing as reductionist approaches continue. As a 'way forward' it is suggested that weathering, stripped of specific preconceived notions of specific processes, be envisaged as a function of energy transfer and be investigated in that light. Identification of new processes as well as restructuring of known processes, particularly when considering weathering on other planets, is a potential outcome of such an approach. With a process foundation rooted in energy transfer, 'rock decay' provides a better umbrella term and liberates researchers from the inescapable conceptual baggage implicit to the term 'weathering'.

Hall, Kevin; Thorn, Colin; Sumner, Paul

2012-05-01

166

Weather Forecasting  

NSDL National Science Digital Library

This activity (on page 2 of the PDF) is a full inquiry investigation into meteorology and forecasting. Learners will research weather folklore, specifically looking for old-fashioned ways of predicting the weather. Then, they'll record observations of these predictors along with readings from their own homemade barometer, graphing the correct predictions for analysis. Relates to linked video, DragonflyTV: Forecasting.

Twin Cities Public Television, Inc.

2005-01-01

167

Weather Instruments.  

ERIC Educational Resources Information Center

|This booklet presents some activities to measure various weather phenomena. Directions for constructing a weather station are included. Instruments including rain gauges, thermometers, wind vanes, wind speed devices, humidity devices, barometers, atmospheric observations, a dustfall jar, sticky-tape can, detection of gases in the air, and pH of…

Brantley, L. Reed, Sr.; Demanche, Edna L.; Klemm, E. Barbara; Kyselka, Will; Phillips, Edwin A.; Pottenger, Francis M.; Yamamoto, Karen N.; Young, Donald B.

168

Weather Forecasting  

NSDL National Science Digital Library

Weather Forecasting is a set of computer-based learning modules that teach students about meteorology from the point of view of learning how to forecast the weather. The modules were designed as the primary teaching resource for a seminar course on weather forecasting at the introductory college level (originally METR 151, later ATMO 151) and can also be used in the laboratory component of an introductory atmospheric science course. The modules assume no prior meteorological knowledge. In addition to text and graphics, the modules include interactive questions and answers designed to reinforce student learning. The module topics are: 1. How to Access Weather Data, 2. How to Read Hourly Weather Observations, 3. The National Collegiate Weather Forecasting Contest, 4. Radiation and the Diurnal Heating Cycle, 5. Factors Affecting Temperature: Clouds and Moisture, 6. Factors Affecting Temperature: Wind and Mixing, 7. Air Masses and Fronts, 8. Forces in the Atmosphere, 9. Air Pressure, Temperature, and Height, 10. Winds and Pressure, 11. The Forecasting Process, 12. Sounding Diagrams, 13. Upper Air Maps, 14. Satellite Imagery, 15. Radar Imagery, 16. Numerical Weather Prediction, 17. NWS Forecast Models, 18. Sources of Model Error, 19. Sea Breezes, Land Breezes, and Coastal Fronts, 20. Soundings, Clouds, and Convection, 21. Snow Forecasting.

Nielsen-Gammon, John

1996-09-01

169

Weather One  

NSDL National Science Digital Library

This website contains summaries and lessons about various aspects of weather. This includes the seasons, types of clouds, air, winds, global warming, hurricanes, tornadoes and lightning. Worksheets are provided to accompany the lesson themes.

Friend, Duane

170

Space Weather  

NASA Astrophysics Data System (ADS)

Following James Van Allen's discovery of Earth's radiation belts (1958), it was immediately recognized that the space environment would be hostile to the communications satellites that had been envision by Arthur Clark (1945) and John Pierce (1955). Van Allen's discovery set off a burst of "space weather" research and engineering that continues to today, paralleling "space weather" research that had, prior to 1958, been directed toward understanding environment effects on cable and early wireless communications, electric power distribution, and pipelines. Van Allen's discovery also meant that the flight of humans above the sensible atmosphere would be fraught with more peril than mere weightlessness. This Van Allen lecture will discuss the space weather considerations that arose from Van Allen's discovery as well as space weather effects that occur from numerous other physical processes in the complex sun-heliosphere-magnetosphere environmental system.

Lanzerotti, L. J.

2005-05-01

171

Sedimentary Rocks: Carbonate Rocks  

NSDL National Science Digital Library

Sedimentary Rocks: Carbonate Rocks is a course handout meant to accompany the discussion of chemical and biochemical sedimentary rocks. Rock composition is broken into the main categories of limestone and dolostone. Depositional conditions are discussed, including the topics of coral reefs, plankton, and carbonate compensation depth (CCD). There are a few photographs, which display calcareous algae. Links are provided to the online Physical Geology resources at Georgia Perimeter College.

Gore, Pamela

172

Rock Cycle: Environments of Formation  

NSDL National Science Digital Library

This Science Object is the second of four Science Objects in the Rocks SciPack. It provides an in-depth exploration of the conditions and environment required during the formation of igneous, sedimentary, and metamorphic rocks. Igneous rock forms from the cooling and crystallization of magma. Sometimes the magma reaches Earth's surface and cools quickly; sometimes it does not reach the surface and thus cools slowly. Rocks at Earth's surface are subjected to processes of weathering and erosion, producing sediments as they are broken down. Sedimentary rock is formed when sediments are buried and solidified through various processes. Sedimentary rock buried deep enough may be transformed into metamorphic rock or melted down to magma. Rock formed deep within the crust (either igneous or metamorphic) may be forced up again to become land surface and even mountains by the forces that drive the motion of Earth's plates. Subsequently, this new rock too will erode. Learning Outcomes:� Realize that different rocks have specific origins, and that they are the product of any number of processes.� Identify the processes through which igneous, sedimentary, and metamorphic rock form.� Explain the role of intermediary materials such as sediment and magma in the formation of different kinds of rock.� Provide an overarching description of the steps in the rock cycle, the formation of sedimentary rock, the re-forming of rock by heat and pressure, and the process by which re-formed rock can return to the surface.

National Science Teachers Association (NSTA)

2006-11-01

173

National Weather Service: Weather Education  

NSDL National Science Digital Library

The National Weather Service's Office of Climate, Water, and Weather Services has a strong outreach component. This "Education" page offers a range of materials for educators and young people which includes lesson plans, brochures, satellite image collections and career information for the fields of meteorology and climatology. The site doesn't have a search engine, but visitors can scroll through eight topical sections, including "Classroom Materials", "Careers in Weather", and "Graphics, Photos, Images". Science teachers won't want to miss the "Classroom Materials", as they can find materials on the "One Sky, Many Voices" project designed to bring together meteorology projects from around the United States together in a collaborative learning environment. Moving on, the "Graphics, Photos, Images" area contains a range of lightning photos and satellite images organized into categories like "Ocean Events", "Severe Weather", and "Tropical Cyclones".

174

Some topics on geochemistry of weathering: a review.  

PubMed

Weathering is a complex process comprising physical disaggregation, chemical and biological decomposition of rocks and minerals transforming complex structure minerals in simpler ones. Hydrolysis of silicates is perhaps the most important process but associated certainly to biological weathering. It is discussed the role ofwaters: activities/concentrations of chemical species, pH, Eh, importance of complexes. Weathering is not only a destructive process. It can concentrate chemical species and form mineral deposits (kaolin, bauxite, Fe, Mn, P, Nb, Au). Weathering studies are important in pedology, engineering geology, hydrogeology, paleoclimatology and ecology. The use of stonemeal is based upon the study of rock weathering. PMID:17143414

Formoso, Milton L L

2006-12-01

175

Space Weather  

NASA Astrophysics Data System (ADS)

This volume provides a comprehensive overview of our current observational knowledge, theoretical understanding, and numerical capability with regard to the phenomena known as space weather. Space weather refers to conditions on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems, and can endanger human life or health. The rapid advance in these technologies has provided us with unprecedented capability and convenience, and we have come to rely on them more and more. Technology has reduced society's risk to many kinds of natural disasters, but through its own vulnerability, it has actually increased society's risk to space weather. Adverse conditions in the space environment can cause disruption of satellite operations, communications, navigation, and electric power distribution grids, leading to a variety of socioeconomic losses.

Song, Paul; Singer, Howard J.; Siscoe, George L.

176

Isotopic tracers of chemical weathering and consequences for marine geochemical budgets  

Microsoft Academic Search

The mechanical breakdown of rock by physical weathering exerts a significant control on chemical weathering rates because it produces surface area. During periods of icehouse conditions on Earth, the grinding of rock by glacial processes should lead to faster chemical weathering of the continents, perhaps particularly during periods of pronounced climatic variability, like the Quaternary. Evidence is reviewed here for

D. Vance

2011-01-01

177

Unisys Weather  

NSDL National Science Digital Library

The Unisys weather website offers a host of weather analyses and forecasts. In the Analyses link, visitors can find satellite images as well as surface, upper air, and radar images. Visitors can learn the intricacies of Unisys's many forecast models such as the Nested Grid Model (NGM), Aviation Model, and the Rapid Update Cycle (RUC) Model. Users can find archived hurricane data for the Atlantic, the Eastern Pacific, and the Western Pacific. The site also furnishes archived surface maps, infrared satellite images, upper air charts, and sea surface temperature (SST) plots.

178

Weather Forecasting  

NSDL National Science Digital Library

Weather Forecasting is one of several online guides produced by the Weather World 2010 project at the University of Illinois. These guides use multimedia technology and the dynamic capabilities of the web to incorporate text, colorful diagrams, animations, computer simulations, audio, and video to introduce topics and concepts in the atmospheric sciences. This module introduces forecast methods and the numerous factors one must consider when attempting to make an accurate forecast. Sections include forecasting methods for different scenarios, surface features affecting forecasting, forecasting temperatures for day and night, and factors for forecasting precipitation.

2010-01-01

179

The Weather Doctor  

NSDL National Science Digital Library

Published by Spectrum Educational Enterprises, The Weather Doctor Web site is maintained by meteorologist Keith Heidorn. Visitors to the site will find everything from the joys of weather watching, to making rain, to weather history, to much more. Coming from someone who clearly enjoys what they do, this site explores unique aspects of weather including weather people, weather history, and weather and arts.

Heidorn, Keith.

2002-01-01

180

Today's Weather  

NSDL National Science Digital Library

This activity is part of Planet Diary and contains an online exploration of weather maps. Students use current maps to learn about and locate different features such as low-pressure areas and fronts. They then explore how these are related to severe storms.

181

Weather control  

Microsoft Academic Search

Weather modification, the intentional altering of atmospheric conditions to suit the purposes of humankind, has five basic forms: (1) fog dissipation; (2) rain and snow enhancement; (3) hail suppression; (4) lightning suppression; and (5) the abatement of severe storms such as hurricanes and tornadoes. The dissipation of fog and the seeding of clouds with dry ice or silver iodide to

Leepson

1980-01-01

182

Effect of Fine Root Contact on Plant-Induced Weathering of Basalt  

Microsoft Academic Search

The objective of the present study was to provide experimental evidence on the active role of plant roots in rock weathering and the importance of the proximity of roots to rock in the weathering process. The analysis was based on the release of different elements from basalt rock particles by three crop species: rice, soybean and maize. Quantitative results were

Meheruna Akter; Tasuku Akagi

2005-01-01

183

Heterogeneous distribution of nanophase aluminosilicate weathering products: Interpreting Martian weathering  

NASA Astrophysics Data System (ADS)

Nanocrystalline alteration products form in a range of soil and regolith weathering environments on Earth. In some weathering systems, poorly crystalline aluminosilicates such as allophane are distributed heterogeneously, as a function of depth in a vertical weathering profile or as a function of micro-environmental factors. Both of these factors can be important for understanding weathering processes on Earth and are particularly important to consider when interpreting allophane on Mars. Chemical and mineralogical measurements of Mars could be confounded by a vertical heterogeneity common to many weathering systems, because what is observed at the surface by spacecraft may not be representative of the complete weathering system. Appropriate caution should be taken to compare surface measurements of Mars to terrestrial weathering environments that examine soil columns. Also, nanocrystalline aluminosilicates are known to form coatings on regolith particles and rock fragments and can be compositionally distinct from weathering products formed in the greater regolith matrix. These types of coatings are particularly important to consider for interpreting remotely sensed spectral measurements because fragmented rocks, from sand to boulders, comprise much of the relatively dust-free surfaces of Mars. Due to their strong influence on spectral observations, coatings could be strongly detectable by thermal infrared spectroscopy relative to coexisting, weakly aggregated fine-grained weathering products, resulting in the oversampling of coatings. Consequently, detected nanocrystalline aluminosilicates phases may not represent the overall weathering system. As an example of these influences, we will consider the high-silica material(s) detected in Mars northern plains. Although there are several models for how this material formed, if it formed by in situ regolith weathering then the high-silica material was precipitated from dissolved regolith materials. Evidence for extensive cryoturbation in the northern plains indicates that subsurface materials have been brought to the surface, thus any vertical compositional heterogeneity resulting from weathering may have been subsequently homogenized. However, small-scale compositional heterogeneities could persist. Although high-silica material may coat particulates that comprise much of the surface, it may only represent only a micro-environment of the subsurface weathering. For example, although we suggest that the northern plains contain a silica-rich allophanic phase, weathering may also have produced more aluminous phases that are undetected in spectra because they do not form coatings. In addition, we will consider the possibility that Martian weathering produces poorly crystalline aluminosilicate phases that are structurally different from true allophane. We will report on the thermal infrared spectral difference between these phases. The details of Martian weathering processes that can be inferred from detection of allophane are limited by how well vertical and micro-environmental heterogeneities are understood and compensated for, for which input from the terrestrial weathering and soil science communities is essential.

Kraft, M. D.; Sharp, T. G.; Rampe, E. B.

2011-12-01

184

Salt weathering in dual-porosity building dolostones  

Microsoft Academic Search

The influence of rock fabric on physical weathering due to the salt crystallization of selected brecciated dolostones is discussed. These dual-porosity dolostones are representative of heterogeneous and anisotropic building rocks, and present highly complex and heterogeneous rock fabric features. The pore structure of the matrix and clasts is described in terms of porosity and pore size distribution, whereas the relative

D. Benavente; J. Martínez-Martínez; N. Cueto; M. A. García-del-Cura

2007-01-01

185

Rad Rocks  

NSDL National Science Digital Library

Why do we have rocks? How are rocks formed? Why do we have rock cycles? There are all differnt kinds of rocks. What parts make up rocks? Can you sort rocks based on color, hardness, texture, layering, and particle size? How do the things rocks are made of determine how people use them? Organize rocks by color, weight, shape, and sizes. Click here to find out the basics about ...

2010-04-26

186

Weather Watchers  

NSDL National Science Digital Library

Students are introduced to some essential meteorology concepts so they more fully understand the impact of meteorological activity on air pollution control and prevention. First, they develop an understanding of the magnitude and importance of air pressure. Next, they build a simple aneroid barometer to understand how air pressure information is related to weather prediction. Then, students explore the concept of relative humidity and its connection to weather prediction. Finally, students learn about air convection currents and temperature inversions. In an associated literacy activity, students learn how scientific terms are formed using Latin and Greek roots, prefixes and suffixes, and are introduced to the role played by metaphor in language development. Note: Some of these activities can be conducted simultaneously with the air quality activity (What Color Is Your Air Today?) of Air Pollution unit, Lesson 1.

Integrated Teaching And Learning Program

187

Weathering: methods and techniques to measure  

NASA Astrophysics Data System (ADS)

Surface recession takes place when weathered material is removed from the rocks. In order to know how fast does weathering and erosion occur, a review of several methods, analyses and destructive and non-destructive techniques to measure weathering of rocks caused by physico-chemical changes that occur in bedrocks due to salt crystallization, freezing-thaw, thermal shock, influence of water, wind, temperature or any type of environmental agent leading to weathering processes and development of soils, in-situ in the field or through experimental works in the laboratory are addressed. From micro-scale to macro-scale, from the surface down to more in depth, several case studies on in-situ monitoring of quantification of decay on soils and rocks from natural landscapes (mountains, cliffs, caves, etc) or from urban environment (foundations or facades of buildings, retaining walls, etc) or laboratory experimental works, such as artificial accelerated ageing tests (a.a.e.e.) or durability tests -in which one or more than one weathering agents are selected to assess the material behaviour in time and in a cyclic way- performed on specimens of these materials are summarised. Discoloration, structural alteration, precipitation of weathering products (mass transfer), and surface recession (mass loss) are all products of weathering processes. Destructive (SEM-EDX, optical microscopy, mercury intrusion porosimetry, drilling resistance measurement, flexural and compression strength) and Non-destructive (spectrophotocolorimetry, 3D optical surface roughness, Schmidt hammer rebound tester, ultrasound velocity propagation, Nuclear Magnetic Resonance NMR, X ray computed micro-tomography or CT-scan, geo-radar differential global positioning systems) techniques and characterization analyses (e.g. water absorption, permeability, open porosity or porosity accessible to water) to assess their morphological, physico-chemical, mechanical and hydric weathering; consolidation products or methods to stop or to slow down their weathering or durability and stability of soils and rocks are also topics where the methods and techniques deal with the quantification of weathering. Cultural stone weathering studies contribute substantially to the knowledge of weathering rates revealing the importance of specific weathering agents and weathering factors.

Lopez-Arce, P.; Zornoza-Indart, A.; Alvarez de Buergo, M.; Fort, R.

2012-04-01

188

Weather Cycles  

NASA Astrophysics Data System (ADS)

This completely updated edition explores in detail the unresolved debate on the existence of weather cycles. It provides a different perspective on one of the most difficult questions in the current global warming debate: how much of the recent temperature rise can be attributed to natural causes? The book examines the complex analysis required to assess the evidence for cycles with a minimum of mathematics. First Edition Hb (1992): 0-521-38178-9 First Edition Pb (1995): 0-521-47869-3

Burroughs, William James

2003-12-01

189

Aviation weather radar  

Microsoft Academic Search

The Federal Aviation Administration has established three ground-based weather radar programs. The terminal Doppler weather radar (TDWR) and weather system processor (WSP) provide wind shear detection capability for air traffic controllers in the terminal area. These systems also reduce weather related delays. The next generation weather radar (NEXRAD) is used by the FAA to improve safety and reduce weather related

D. H. Turnbull

1995-01-01

190

Weather Science Hotlist  

NSDL National Science Digital Library

The Franklin Institute Online offers the metadata Web site Weather Science Hotlist. The page contains dozens of links organized into ten topics that include Online Exhibits, Weather Right Now, Background Information, Severe Weather, El Nino/ La Nina, Historical Weather, Career Connections, Activities, Atmosphere, and Weather Forecasting. A great source for anyone looking for online weather information.

1969-12-31

191

Rock-degrading endophytic bacteria in cacti  

Microsoft Academic Search

A plant–bacterium association of the cardon cactus (Pachycereus pringlei) and endophytic bacteria promotes establishment of seedlings and growth on igneous rocks without soil. These bacteria weather several rock types and minerals, unbind significant amounts of useful minerals for plants from the rocks, fix in vitro N2, produce volatile and non-volatile organic acids, and reduce rock particle size to form mineral

M. Esther Puente; Ching Y. Li; Yoav Bashan

2009-01-01

192

Anisotropie verticale de la perméabilité de l'horizon fissuré des aquifères de socle : concordance avec la structure géologique des profils d'altération Vertical anisotropy of hydraulic conductivity in fissured layer of hard-rock aquifers due to the geological structure of weathering profiles  

NASA Astrophysics Data System (ADS)

Pumping tests carried out in the fissured layer of a granitic hard-rock aquifer, interpreted at the observation wells by means of the analytical solution of Neuman and at the pumping wells with that of Gringarten show the existence of a strong vertical anisotropy of this layer of the aquifer; the horizontal permeability is clearly and systematically higher than the vertical one. These results agree perfectly with the geological observations, the fissured layer of the weathered granite profile showing the existence of many sub-horizontal fissures. It confirms that, within the fissured layer, the permeability of sub-horizontal fissures due to the weathering process dominates over that of sub-vertical fissures of tectonic origin. To cite this article: J.-C. Maréchal et al., C. R. Geoscience 335 (2003).To cite this article: J.-C. Maréchal et al., C. R. Geoscience 335 (2003).

Maréchal, Jean-Christophe; Wyns, Robert; Lachassagne, Patrick; Subrahmanyam, Kambhampati; Touchard, Frédéric

2003-05-01

193

Destructive Weather  

NSDL National Science Digital Library

What are the effects of different types of destructive weather? Learn All About Hurricanes Record on your chart 3 things that you learned. Watch a Hurricane Video These are the devastating Effects of Hurricanes Learn All About Tornadoes Record on your chart 3 things that you learned. Watch a Tornado Video These are the devastating Effects of tornadoes Learn All About Thunderstorms Record on your chart 3 things that you learned. These are the devastating Effects of thunderstorms Follow these important tips To keep safe. ...

Alizabethirwin

2010-11-03

194

Weather Tamers  

NSDL National Science Digital Library

Problem-based learning experiences that extend at least two weeks provide an opportunity for students to investigate a real-world problem while learning science content and skills in an exciting way. Meteorology provides a wealth of problems students can investigate while learning specific science concepts and skills found frequently in middle level national and state curricula standards. The hands-on activity described in this article helps students learn about the science behind weather events by planning, constructing, and testing models of cities exposed to a series of simulated hurricanes and tornado conditions.

Sterling, Donna R.; Frazier, Wendy M.

2007-03-01

195

Observe the effects of mechanical weathering  

NSDL National Science Digital Library

In this interactive Earth science resource, students are first presented with six photographs, each featuring a different mechanical weathering event in which rock is broken down. Examples of the events include road damage due to ice heaving and the expansion of cracks in rocks due to tree growth. Students are instructed to click on each labeled image to see an enlarged version of it. In the enlarged view, brief text, often accompanied by visual cues such as arrows, explains the physical weathering process shown. Copyright 2005 Eisenhower National Clearinghouse

Education, Terc. C.; Littell, Mcdougal

2003-01-01

196

Talking Rocks.  

ERIC Educational Resources Information Center

Discusses some of the ways that rocks can be used to enhance children's creativity and their interest in science. Suggests the creation of a dramatic production involving rocks. Includes basic information on sedimentary, igneous, and metamorphic rocks. (TW)

Rice, Dale; Corley, Brenda

1987-01-01

197

The Weather Dude  

NSDL National Science Digital Library

The Weather Dude is a weather education Web site offered by meteorologist Nick Walker of The Weather Channel. For kids, the site offers a great online textbook entitled Weather Basics, which explains everything from precipitation to the seasons, using simple text and fun graphics. Other fun things for kids include weather songs, questions and quizzes, weather proverbs, and more. Teachers are also provided with helpful resources such as weather activity sheets and printable blank maps, as well as many other links to weather forecasts and information that will help make teaching about weather fun.

Walker, Nick.

2002-01-01

198

Investigating Factors that Influence Weathering of Monuments in a Cemetery  

NSDL National Science Digital Library

In this field activity students will discover some of the factors that influence weathering of rock by making observations, asking questions and completing an investigation of their own design in a local cemetery.

199

Forecasting the Weather.  

ERIC Educational Resources Information Center

|Presents a computer program which predicts the weather based on student input of such weather data as wind direction and barometric pressure. Also provides procedures for several hands-on, weather-related activities. (JN)|

Bollinger, Richard

1984-01-01

200

Weather Prediction Models  

NASA Astrophysics Data System (ADS)

Awareness of weather and concern about weather in the proximate future certainly must have accompanied the emergence of human self-consciousness. Although weather is a basic idea in human existence, it is difficult to define precisely.

Bacmeister, Julio T.

201

Cockpit Weather Information Needs.  

National Technical Information Service (NTIS)

The primary objective is to develop an advanced pilot weather interface for the flight deck and to measure its utilization and effectiveness in pilot reroute decision processes, weather situation awareness, and weather monitoring. Identical graphical weat...

C. H. Scanlon

1992-01-01

202

National Weather Service  

MedlinePLUS

... CURRENT CONDITIONS Radar Climate Monitoring River Levels Observed Precipitation Surface Weather Upper Air Marine and Buoy Reports ... Weather Current Outlook Maps Drought Fire Weather Fronts/Precipitation Maps Current Graphical Forecast Maps Rivers Marine Offshore ...

203

What's the Weather?  

NSDL National Science Digital Library

In this lesson, students use daily observations, videos, and activities to learn about meteorology and the changing nature of weather. Students also identify weather events that are commonly reported in the news and discuss how weather affects lives.

Foundation, Wgbh E.

2009-07-21

204

Migration and enrichment of trace elements of Lower Palaeozoic carbonate rock strata in Beijing  

Microsoft Academic Search

Analyses of trace elements of the Lower Palaeozoic carbonate rock strata in Beijing show that the contents of As, Hg, F increase\\u000a from primary carbonate rocks to weathered carbonate rocks and from primary carbonate rocks to the soil coexisting with carbonate\\u000a rocks, but the distribution regularity of S is not obvious. In the whole weathered stages, the sorption of As

ShanQin Ni; QuanLin Hou; YiWen Ju; LingLing Xiao; YuDong Wu; Qing Liu

2008-01-01

205

Soil Genesis and Development, Lesson 2 - Processes of Weathering  

Technology Transfer Automated Retrieval System (TEKTRAN)

Weathering processes — which include physical, chemical, and biological — contribute to the development of soil. The learning objectives of the lesson are: 1) Define and distinguish physical, chemical, and biological weathering processes; and 2) Describe how rock and mineral properties and environm...

206

Effects of climate on chemical_ weathering in watersheds  

Microsoft Academic Search

Climatic effects on chemical weathering are evaluated by correlating variations On solute concentrations and fluxes with temperature, precipitation, runoff, and evapotranspiration (ET) for a worldwide distribution of sixty-eight watersheds underlain by granitoid rock types. Stream solute concentrations are strongly correlated with proportional ET loss, and evaporative concentration makes stream solute concentrations an inappropriate surrogate for chemical weathering. Chemical fluxes are

Art F. White; Alex E. Blum

1995-01-01

207

Does mineral surface area affect chemical weathering rates?  

Microsoft Academic Search

Iceland is a basaltic volcanic island representative of the high relief, volcanic and tectonic active islands that contribute over 45% of river suspended material to the oceans worldwide (Milliman and Syvitski, 1992). These islands have enormous mechanical and chemical weathering rates due to the combined effects of high relief, high runoff, the presence of glaciers and easily weathered volcanic rocks,

Eydis Salome Eiriksdottir; Sigurdur Reynir Gislason; Eric H. Oelkers

2010-01-01

208

Mechanics of Sheeting Joints and Spheroidal Weathering (Invited)  

Microsoft Academic Search

Physical weathering in low-porosity materials, like most crystalline rocks, commonly involves fracture, which increases the surface area that can be accessed by reactive chemicals. Chemical reactions on these surfaces can in turn affect the course of further fracturing. Physical and chemical weathering thus commonly go hand in hand, although one process can dominate the other. Two common products of physical

S. J. Martel

2010-01-01

209

Rock Solid  

NSDL National Science Digital Library

A teacher describes how developing a structured, focused, and fun curriculum on rocks and minerals for learning-disabled students transformed her initial reluctance about Earth science into enthusiasm. Students observed, described, and sorted rocks and explored rock formation. A sample worksheet is included, as is a list of children's trade books about rocks.

Sorel, Katherine

2003-02-01

210

Igneous Rocks  

NSDL National Science Digital Library

This interactive lesson on igneous rocks begins with a comparison of intrusive and extrusive igneous rocks with diagrams to show their origin. This leads to a discussion of intrusive rock formations including dikes, sills, laccoliths and batholiths and a block diagram to show their location. Basaltic rocks are described to include basalt, pumice, and gabbro and are contrasted with granitic rhyolite and obsidian.

211

rock properties  

NSDL National Science Digital Library

Rocks are the most common material on earth. We will learn about the parts that make up the rocks and sort rocks based upon color, hardness, texture, layering, and particle size. Lets review: What do you already know about rocks? Please write down your thoughts on a piece of paper. Now, click on the link below to find out what the definition of a rock is. *Intro to Rocks Please answer the questions below in complete sentences on your paper. 1. Rocks are made up of several particles. ...

Krystal

2009-12-14

212

Igneous Rocks  

NSDL National Science Digital Library

This site explores igneous rocks in-depth through descriptions and pictures. The formation and distribution of this rock type are covered, as well as magma types associated with them (mafic to felsic). Classification of igneous rocks covers their texture and composition, including the difference between intrusive and extrusive. An alphabetical listing of rocks connects the user with a description, picture, tectonic association, and mineral composition of the rock. Bowens Reaction Series is covered as well, with associated rock types. A self-test allows the user to identify rocks by picture alone. Links are provided to sites with further information.

2007-12-12

213

Metamorphic Rocks  

NSDL National Science Digital Library

This interactive lesson on metamorphic rocks starts with a review of the rock cycle and goes on to describe the relationship between metamorphic rocks and their parent rock. The lesson then describes the agents of metamorphism (temperature, pressure, and chemical change) and moves into a discussion on contact, regional, and dynamic metamorphism. The remainder of the lesson consists of descriptions of foliated rocks such as slate, schist, and gneiss, and the non-foliates exemplified by quartzite and white marble.

214

Release of biodegradable dissolved organic matter from ancient sedimentary rocks  

Microsoft Academic Search

Sedimentary rocks contain the largest mass of organic carbon on Earth, yet these reservoirs are not well integrated into modern carbon budgets. Here we describe the release of dissolved organic matter (DOM) from OM-rich sedimentary rocks under simulated weathering conditions. Results from column experiments demonstrate slow, sustained release of DOM from ancient sedimentary rocks under simulated weathering conditions. 1H-NMR analysis

Sarah Schillawski; Steven Petsch

2008-01-01

215

Long-term stability of global erosion rates and weathering during late-Cenozoic cooling  

Microsoft Academic Search

Over geologic timescales, CO2 is emitted from the Earth's interior and is removed from the atmosphere by silicate rock weathering and organic carbon burial. This balance is thought to have stabilized greenhouse conditions within a range that ensured habitable conditions. Changes in this balance have been attributed to changes in topographic relief, where varying rates of continental rock weathering and

Jane K. Willenbring; Friedhelm von Blanckenburg

2010-01-01

216

Role of fine roots in the plant-induced weathering of andesite for several plant species  

Microsoft Academic Search

The present work aims at providing experimental evidence for weathering as a direct consequence of plant physiology, and the importance of the proximity of fine roots to rock in the weathering process. Discussion is based on the release of different elements from andesite rock particles by the three crop species: rice, maize, and soybean. We designed two types of hydroponic

AKTER MEHERUNA; TASUKU AKAGI

2006-01-01

217

Effect of microstructure and weathering on the strength anisotropy of porous rhyolite  

Microsoft Academic Search

To study the effect of microstructure and weathering on the strength anisotropy of rock, unconfined compressive strength (UCS) tests were carried out on three porous rhyolites having the same original lithology, but different weathering periods of 2600, 20,000 and 40,000 years. The rock is mainly composed of glassy groundmass, with flow structure. UCS tests were undertaken on a series of

Y Matsukura; K Hashizume; C. T Oguchi

2002-01-01

218

Interpreting a Weathered Mars: Investigating the Effects of Weathering on Spectroscopic Observations Through Laboratory Study  

NASA Astrophysics Data System (ADS)

Infrared spectroscopy is a critical tool for Martian mineralogy. Because it is crucial to evaluate the history of water on Mars, mineralogical study of weathering and alteration is among the most important topics of Mars spectroscopy. The state of alteration of the Martian surface is evaluated by the presence or absence of alteration phases and their overall abundance. Interpretations of Martian weathering processes are based on the types of alteration products, the mineral assemblages, and derived chemistry. The spectroscopy of alteration minerals has been studied in detail for decades; however, detecting and identifying alteration products from remotely- sensed spectra of natural surfaces is complicated by microtextural mixing of rock-forming minerals, alteration products, and void space. We are investigating the effects that low-temperature weathering has on spectral observations in order to facilitate interpretation of spectroscopic data of Martian surfaces that may be weathered. Our approach has been to characterize the infrared spectra, mineral assemblages, and textures of weathering rinds and rock coatings formed on volcanic rocks in a variety of environments. This approach enables us to witness the spectral variability that results from weathering and tie it to differences in texture or mineralogical composition. More importantly, by examining numerous rinds and coatings, we can determine what effects are common to broader weathering phenomena. For instance, basalt weathering typically leads to systematic changes in silicate vibrational absorptions that can hamper spectral modeling techniques used to assess Martian data. In addition, weathered surfaces may show little evidence of hydrated minerals in near-infrared data. Another important component of our research is the use of controlled laboratory experiments designed to simplify, yet emulate, important attributes of the naturally weathered surfaces, in order to better constrain the spectral effects of weathering. Based on our findings regarding weathering mineral detectability, assertions that Mars has lacked aqueous weathering in its latter history may be incorrect. Rather, we suggest that volumetrically small amounts of high-silica weathering products formed in aqueous environments at middle and high latitudes and that this is consistent with spectroscopic observations of Mars.

Kraft, M. D.; Sharp, T. G.; Michalski, J. R.; Rampe, E. B.

2007-12-01

219

CRONO—A code for the simulation of chemical weathering  

NASA Astrophysics Data System (ADS)

CRONO is a new code for simulating chemical weathering. This program allows for the simulation of complex scenarios of interaction in water-rock-gas systems while accounting for mineral dissolution kinetics and solution transport. The thermodynamic calculations are realized using the GEOCHEQ program. CRONO was developed for simulations of regolith formation on the surfaces of early Earth and Mars and can be applied to other targets formed mainly as a result of chemical weathering. In this paper, an application of the code using a simulation of modern subaerial weathering of basaltic rocks is presented.

Novoselov, Alexey A.; Souza Filho, Carlos Roberto

2013-10-01

220

Future Weather Station  

NSDL National Science Digital Library

In this activity students build dioramas of futuristic weather stations to demonstrate their knowledge of weather forecasting. They will work in groups to research modern forecasting equipment and techniques, and then build a weather station that will do something we cannot do at present (such as stopping tornadoes). They will present their dioramas and then discuss the pros and cons of controlling the weather.

221

Weather in Your Life.  

ERIC Educational Resources Information Center

|Facts and activities related to weather and meteorology are presented in this unit. Separate sections cover the following topics: (1) the water cycle; (2) clouds; (3) the Beaufort Scale for rating the speed and force of wind; (4) the barometer; (5) weather prediction; (6) fall weather in Iowa (sleet, frost, and fog); (7) winter weather in Iowa…

Kannegieter, Sandy; Wirkler, Linda

222

Controlling The Global Weather  

Microsoft Academic Search

the weather controller is extremely complex, the existence of the required technology is plausible in the time range of several decades.While the concept of controlling the weather has often appeared in science fiction literature, this statement of the problem provides a scientific basis and a system architecture to actually implement global weather control. Large-scale weather control raises important legal and

Ross N. Hoffman

2002-01-01

223

Lithium isotope history of Cenozoic seawater: changes in silicate weathering and reverse weathering.  

PubMed

Weathering of uplifted continental rocks consumes carbon dioxide and transports cations to the oceans, thereby playing a critical role in controlling both seawater chemistry and climate. However, there are few archives of seawater chemical change that reveal shifts in global tectonic forces connecting Earth ocean-climate processes. We present a 68-million-year record of lithium isotopes in seawater (?(7)Li(SW)) reconstructed from planktonic foraminifera. From the Paleocene (60 million years ago) to the present, ?(7)Li(SW) rose by 9 per mil (‰), requiring large changes in continental weathering and seafloor reverse weathering that are consistent with increased tectonic uplift, more rapid continental denudation, increasingly incongruent continental weathering (lower chemical weathering intensity), and more rapid CO(2) drawdown. A 5‰ drop in ?(7)Li(SW) across the Cretaceous-Paleogene boundary cannot be produced by an impactor or by Deccan trap volcanism, suggesting large-scale continental denudation. PMID:22282473

Misra, Sambuddha; Froelich, Philip N

2012-01-26

224

Weather Derivative Valuation  

NASA Astrophysics Data System (ADS)

Weather Derivative Valuation is the first book to cover all the meteorological, statistical, financial and mathematical issues that arise in the pricing and risk management of weather derivatives. There are chapters on meteorological data and data cleaning, the modelling and pricing of single weather derivatives, the modelling and valuation of portfolios, the use of weather and seasonal forecasts in the pricing of weather derivatives, arbitrage pricing for weather derivatives, risk management, and the modelling of temperature, wind and precipitation. Specific issues covered in detail include the analysis of uncertainty in weather derivative pricing, time-series modelling of daily temperatures, the creation and use of probabilistic meteorological forecasts and the derivation of the weather derivative version of the Black-Scholes equation of mathematical finance. Written by consultants who work within the weather derivative industry, this book is packed with practical information and theoretical insight into the world of weather derivative pricing.

Jewson, Stephen; Brix, Anders

2005-04-01

225

Geology of the Oceanic Crust: Magnetic Properties of Oceanic Rocks  

Microsoft Academic Search

A diverse suite of rocks has been sampled from ocean basin escarpments in the North Atlantic and the Caribbean: fresh and weathered basalts, metabasalts (zeolite and greenschist facies), gabbros, met, agabbros (greenschist and amphiolite facies), serpentinized peridotites, and actinolite rocks. One hundred and three representative specimens were chosen from this diverse suite of rocks, and the natural remanent magnetization (NRM)

Paul J. Fox; Neil D. Opdyke

1973-01-01

226

Geomicrobiology of a Weathering Crust from an Impact Crater and a Hypothesis for its Formation  

Microsoft Academic Search

Understanding the role of microbe-mineral interactions in rock weathering is vital to an understanding of nutrient availability to the biosphere and, in so far as weathering influences carbon dioxide drawdown, climate control. We studied a weathering crust on a resurge tsunami deposit (Loftarstone) from the ? 455 Ma old Lockne impact crater, central Sweden with an integrated approach using XRD,

Charles S. Cockell; Niki Kennerley; Maurits Lindstrom; Jonathan S. Watson; Vala Ragnarsdottir; Erik Sturkell; Sieglinde Ott; Andrew G. Tindle

2007-01-01

227

Exploring links between vadose zone hydrology and chemical weathering in the Boulder Creek critical zone observatory  

Microsoft Academic Search

Understanding the relationship between subsurface flow paths on hillslopes and chemical weathering of bedrock is fundamental to understanding the timing and mechanisms that weather bedrock to saprolite. The link between chemical weathering of bedrock and contact time with reactive water along flow paths motivates this study. Water drives the chemical alteration of rock into saprolite, yet connected porosity generally declines

Abigail L. Langston; Gregory E. Tucker; Robert S. Anderson; Suzanne P. Anderson

2011-01-01

228

Relationship between mineral weathering and groundwater composition  

NSDL National Science Digital Library

In this pair of activities, students start by using published data to predict what will happen to groundwater composition as a consequence of chemical weathering. The data are provided in a spreadsheet (Hinman_weathering). Students are given the histograms only; both are normalized to 100 %, while one includes silica and the other does not. Students must use resources to predict how groundwater composition will change as a consequence of the observed weathering, and support those predictions using balanced chemical-weathering equations. Afterwards, they conduct a laboratory experiment in which they subject crushed rock to four types of solutions (acid solution, organic-rich solution, rainwater, and alkaline solution). The pH of each solution is measured, and subsequently adjusted after 24 and 48 hours. Solutions are sampled after 14 days. They are analyzed by ICP, and the compositions reported to students for comparison with their predictions.

Hinman, Nancy

229

Australian Severe Weather  

NSDL National Science Digital Library

The Australian Severe Weather Web site is maintained by self proclaimed severe weather enthusiasts Michael Bath and Jimmy Deguara. Other weatherphobes will fully appreciate what the authors have assembled. Everything from weather images, storm news, tropical cyclone data, bush fire and wild fire information, weather observation techniques, and even video clips and Web cam links. Although these other items make the site well rounded, the extensive amount of categorized weather pictures (which are quite extraordinary) are reason enough to visit.

230

Rock Art  

ERIC Educational Resources Information Center

|There are many interpretations for the symbols that are seen in rock art, but no decoding key has ever been discovered. This article describes one classroom's experiences with a lesson on rock art--making their rock art and developing their own personal symbols. This lesson allowed for creativity, while giving an opportunity for integration…

Henn, Cynthia A.

2004-01-01

231

Rock Finding  

ERIC Educational Resources Information Center

|In this article, the authors discuss a literature-based activity that helps students discover the importance of making detailed observations. In an inspiring children's classic book, "Everybody Needs a Rock" by Byrd Baylor (1974), the author invites readers to go "rock finding," laying out 10 rules for finding a "perfect" rock. In this way, the…

Rommel-Esham, Katie; Constable, Susan D.

2006-01-01

232

Collecting Rocks.  

ERIC Educational Resources Information Center

One of a series of general interest publications on science topics, the booklet provides those interested in rock collecting with a nontechnical introduction to the subject. Following a section examining the nature and formation of igneous, sedimentary, and metamorphic rocks, the booklet gives suggestions for starting a rock collection and using…

Barker, Rachel M.

233

Metamorphic Rocks  

NSDL National Science Digital Library

Here is an in-depth description of metamorphic rocks, from their classification to formation and identification. It covers types of metamorphism (including Barrovian, or regional rock changes), classification by foliation, and metamorphic processes (facies and zones). An alphabetical list of rocks with picture, composition, description, tectonic association, and type of metamorphism is given. Common metamorphic minerals are covered as well.

2007-12-12

234

Edheads: Weather Activities  

NSDL National Science Digital Library

This great interactive resource allows you multiple opportunities to explore weather related concepts. After clicking start, you will learn how to report and predict the weather at the underground W.H.E.D weather caves! Each activity has three different levels, and each level is harder than the one before it. This resource also includes a teacher's guide (with pre- and post- tests) and links to additional weather related resources. These include a weather glossary, a Fahrenheit to Celsius & Celsius to Fahrenheit converter, and a link that provides information about interesting people in the weather field.

2010-01-01

235

Space Weather FX  

NSDL National Science Digital Library

Space Weather FX is a vodcast (video podcast) series that explores the science of space weather and how it can impact our every day lives. Episodes include Space Weather and its Effects, Connecting the Sun and Earth, When Space Weather Attacks, Stratospheric Sudden Warming, A Tour of Haystack's Radars, GPS and Space Weather, It Came from the Sun, and The Big Picture. The site also contain links to space weather information and educational materials. The episodes will run on one of four free video players.

236

The Weather Man  

NSDL National Science Digital Library

This project is designed to let you be "The Weather Man" and control the weather through simulation, and hands on experience, followed by guided questioning and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. How does humility play a role in weather? How does more or less change weather? 2. What is water vapor? Where does it come from? 3. What happens when the weather drops below zero degrees? ...

Grasser, Mrs. E.

2012-09-27

237

Internet Weather Links: Weather and Weather Related Lesson Plans  

NSDL National Science Digital Library

The Internet Weather Links is a collection of lesson plans provided by the Utah Education Network's Weather Report Web site. The activities are organized by grade level from kindergarten to fourth grade and include such topics as Sunny Colors, Weather in a Box, Changes Due to Freezing, and Geological Features. Each lesson is well organized with explanations of its objectives, intended learning outcomes, and instructional procedures. Downloadable documents, related links, extensions to the lesson, and even rating systems for teachers are also provided, making it a great resource especially for use with younger students.

1996-01-01

238

Air Weather Service Weather-Modification Program.  

National Technical Information Service (NTIS)

The Air Weather Service has recently inaugurated a program to field test those weather-modification techniques within the scientific state-of-the-art and of potential value to the Air Force in order to bring them to a state of operational readiness. The f...

H. S. Appleman

1968-01-01

239

The influence of marine salts, aspect and microbes in the weathering of sandstone in two historic structures  

Microsoft Academic Search

Sandstone weathering rates are compared on two historic structures, one coastal and one inland. Weathering is accelerated at the coastal site by a factor of 1.59, although this value may underestimate the true difference. Intra-site coastal patterns show that aspect creates a threefold variation in weathering rate. Abundant micro-organism growth protects rock, whereas patchy colonisation leads to increased weathering. Weathering

Derek Mottershead; Anna Gorbushina; Gerald Lucas; Janet Wright

2003-01-01

240

Geotechnical properties of weathered and hydrothermally decomposed granite and their influence on slope stability  

Microsoft Academic Search

Weathering and alternation in granite has a deep inpact on both geotechnical properties of the rock as well as of the rock mass. In a granite rock mass, the discontinuity pattern together with joint cohesion and friction plays a major role especially when prone to sliding. These pheneomena could be exclusively studied at the Königshainer Berge Tunnel Project (Lausitz, Germany)

K. Thuro; M. Scholz

2003-01-01

241

Project Weather and Water.  

ERIC Educational Resources Information Center

Introduces Project Weather and Water with the goal of developing and testing ideas of how to implement weather topics and water physics in an integrated way. Discusses teacher preparation, implementation, and evaluation of this project. (ASK)

Hansen, Pal J. Kirkeby

2000-01-01

242

Hot Weather Tips  

MedlinePLUS

Home > Newsletters > Connections newsletter - Archives > Spring 2003 > HOT Weather Tips E-mail to a Friend Printable Version ©Family Caregiver Alliance We all suffer in hot weather. However, for elderly and disabled ...

243

On Observing the Weather  

NSDL National Science Digital Library

In this article, Mount Washington Observatory meteorologist Tim Markle shares the ins and outs of his daily weather-observing routine and offers insights on making weather observations at home or at school.

Crane, Peter

2004-05-01

244

Introduction to Weather  

NSDL National Science Digital Library

This resource provides an overview of weather, the day-to-day changes in temperature, air pressure, moisture, wind, cloudiness, rainfall and sunshine. Links embedded in the text provide access to descriptions of cloud types and to information on weather hazards such as fog, hurricanes, thunderstorms, and tornadoes. Other topics include meteorology, weather measurements, and weather mapping. Materials are also provided on the water cycle and its elements, such as evaporation, uplift and cooling of air, dew point, condensation, and precipitation.

2010-01-01

245

Extreme Weather on Earth  

NSDL National Science Digital Library

In this activity, students utilize a set of photographs and a 30 minute video on weather to investigate extreme weather events. They are posed with a series of questions that ask them to identify conditions predictive of these events, and record them on a worksheet. Climate and weather concepts defined.

Mika, Anna; Education, National G.

246

Weather Maps in Motion  

NSDL National Science Digital Library

In this activity, students learn to interpret current weather maps. They will observe weather map loop animations on the internet, learn the concept of Zulu time (Universal Time Coordinated, UTC) and visualize the movement of fronts and air masses. They will then analyze a specific weather station model, generate a meteogram from their observations, and answer a set of questions about their observations.

Burrows, Charles

247

Weather Fundamentals: Meteorology. [Videotape].  

ERIC Educational Resources Information Center

The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) looks at how meteorologists gather and interpret current weather data collected from sources…

1998

248

Doppler weather radar  

Microsoft Academic Search

The Doppler weather radar and its signals are examined from elementary considerations to show the origin and development of useful weather echo properties such as signal-to-noise ratio (SNR), range correlation, signal statistics, etc. We present a form of the weather radar equation which explicitly shows the echo power loss due to finite receiver bandwidth and how it is related to

RICHARD J. DOVIAK; DUSAN S. ZRNIC; DALE S. SIRMANS

1979-01-01

249

Weather Fundamentals: Meteorology. [Videotape].  

ERIC Educational Resources Information Center

|The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) looks at how meteorologists gather and interpret current weather data collected from sources…

1998

250

Severe Weather Primer  

NSDL National Science Digital Library

The severe weather primer from the National Severe Storms Laboratory of the NOAA provides text and graphic explanations of how severe weather phenomena form. Basics on thunderstorms, tornadoes, floods, hail, lightning, winter weather, and winds are provided in a question-oriented format including answers to frequently asked questions.

Laboratory, National S.

2010-04-24

251

Weather Girl Goes Rogue  

NSDL National Science Digital Library

This humorous video suggests what might happen if a weather forecaster reported the weather in the context of climate change. There is a sharp contrast between the anchor focusing on short-term local concerns and the weather forecaster describing what is happening on a long-term global basis.

Ram, Deep R.; Technologies, Institute F.

252

Weather and Climate Basics  

NSDL National Science Digital Library

This primer from the National Center for Atmospheric Research (NCAR) defines weather and climate, and explains related concepts such as the atmosphere, natural hazards, rising sea level, and modeling. Users explore how dynamic forces within the atmosphere change our weather and climate. They learn what causes weather events and climate change and how NCAR scientists are exploring our atmosphere through scientific research.

2008-01-01

253

American Weather Stories.  

ERIC Educational Resources Information Center

|Weather has shaped United States' culture, national character and folklore; at times it has changed the course of history. The seven accounts compiled in this publication highlight some of the nation's weather experiences from the hurricanes that threatened Christopher Columbus to the peculiar run of bad weather that has plagued American…

Hughes, Patrick

254

Space weather risk  

Microsoft Academic Search

The importance of space weather to society is in a continuous increase since we are more and more dependent on reliable spaceborne and ground-based technological systems. Physical processes involved in space weather constitute a complicated chain from the Sun to the Earth's surface, so the management of space weather risks requires expertise in many disciplines of science and technology. In

Risto Pirjola; Kirsti Kauristie; Hanna Lappalainen; Ari Viljanen; Antti Pulkkinen

2005-01-01

255

Science Rocks!  

ERIC Educational Resources Information Center

|It all began one Monday morning. Raymond could not wait to come to large group. In his hand, he held a chunk of white granite he had found. "Look at my beautiful rock!" he cried. The rock was passed around and examined by each student. "I wonder how rocks are made?" wondered one student. "Where do they come from?" asked another. At this moment, a…

Prestwich, Dorothy; Sumrall, Joseph; Chessin, Debby A.

2010-01-01

256

Earth Rocks!  

NSDL National Science Digital Library

The purpose of this lesson is to introduce students to the basic elements of our Earth's crust: rocks, soils and minerals. They learn how we categorize rocks, soils and minerals and how they are literally the foundation for our civilization. Students also explore how engineers use rocks, soils and minerals to create the buildings, roads, vehicles, electronics, chemicals, and other objects we use to enhance our lives.

Integrated Teaching And Learning Program

257

Sampling Rocks  

NSDL National Science Digital Library

In this lesson, students will learn about sampling through an investigation of rocks found in the schoolyard. This will provide a start to understanding everyday statistics. They will first collect and analyze a sample of rocks from the schoolyard and array the collected rocks by characteristics such as size, weight, and color, to see if any generalizations can be made about the types of rocks that can be found in the schoolyard. Students will then be introduced to the notion of a sample and how the size and method of collection of a sample can bias findings.

258

Fabulous Weather Day  

NSDL National Science Digital Library

Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. After studying weather for three months, we celebrate what we have learned and stretch our thinking further into the weather world around us! Students learn how meteorologists collect data about the weather, how they study wind, temperature, precipitation, basic types/characteristics of clouds, and how they forecast. The project helps the students grow in their understanding of how the weather works and how it can affect their lives. Our unit focused on guiding students to formulate explanations about animals based on scientific evidence.

Marshall, Candice; Mogil, H. M.

2007-01-01

259

[Weathering seasonal variations in karst valley in southwest China].  

PubMed

Jialing River is a 1st grade tributary of upstream Yangzi River. In two years, Samples were collected monthly in Wentang Gorge section of Jialing River and analyzed multi-parameters including hydrochemistry and isotopes. Thus, a general result was concluded that the hydrochemical characteristic of Jialing River in Wentang gorge is controlled by weathering of stratum and the hydrochemical type is HCO3(-) -Ca. Most irons were influenced by dilution, which had higher concentrations in dry season than that in rainy season, but nitrate. Nitrate, which was controlled by human activities, has higher concentrations in rainy season. However, some other analyst revealed weathering impacts. The contrast ratio of (Ca(2+) + Mg2+) and HCO3- were between 0.5-1, the same as (Ca(2+) + Mg2+) and (HCO3(-) + SO4(2-)), Which implied that the weathering impacts in this basin was mainly carbonated and sulfate weathering of carbonated, and sulphate rocks weathering was not so significant. The values of delta13C(HCO3- in Jialing River were -8.74 per thousand(-) - 7.36 per thousand, and delta34S(SO)(4)2 - was 14.43 per thousand in dry season and 12.21 per thousand in rainy season. The data of isotopes inferred that, in rainy season sulfate weathering of carbonated and sulphate rocks weathering both had more impacts and sulphate rocks weathering played a more important role than sulfate weathering of carbonated, but, in dry season, carbonated weathering of carbonated was more meaningful. PMID:22720555

Xiao, Qiong; Shen, Li-Cheng; Yang, Lei; Wu, Kun-Yu; Chen, Zhan-Tu

2012-04-01

260

Avalanche Weather Forecasting  

NSDL National Science Digital Library

Avalanches form through the interaction of snowpack, terrain, and weather, the latter being the focus of this module. The module begins with basic information about avalanches, highlighting weather's role in their development. The rest of the module teaches weather forecasters how to make an avalanche weather forecast, that is, one in which key weather parameters are evaluated for their impact on avalanche potential. The forecasts are used primarily by avalanche forecasters, who integrate them with other information to determine when to issue avalanche hazard warnings. The module contains five cases that let users apply the avalanche weather forecast process to different combinations of snowpack, terrain, and weather conditions. It is a companion to the COMET module "Snowpack and Its Assessment," which describes snowpack development and various assessment techniques.

Linder, Dave

2011-01-01

261

11. COULTERVILLE ROAD AT ROCK SLIDE AREA WITH HWY 140 ...  

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

11. COULTERVILLE ROAD AT ROCK SLIDE AREA WITH HWY 140 AT REAR. LOOKING NNE. GIS: N-37 43 04.7 / W-119 43 00.3 - Coulterville Road, Between Foresta & All-Weather Highway, Yosemite Village, Mariposa County, CA

262

Beyond the Weather Chart: Weathering New Experiences.  

ERIC Educational Resources Information Center

Describes an early childhood educator's approach to teaching children about rain, rainbows, clouds, precipitation, the sun, air, and wind. Recommends ways to organize study topics and describes experiments that can help children better understand the different elements of weather. (MOK)

Huffman, Amy Bruno

1996-01-01

263

Beyond the Weather Chart: Weathering New Experiences.  

ERIC Educational Resources Information Center

|Describes an early childhood educator's approach to teaching children about rain, rainbows, clouds, precipitation, the sun, air, and wind. Recommends ways to organize study topics and describes experiments that can help children better understand the different elements of weather. (MOK)|

Huffman, Amy Bruno

1996-01-01

264

National Weather Service- Severe Weather Awareness  

NSDL National Science Digital Library

This website provides access to information designed to protect and prepare individuals from severe weather. Materials presented here include forecasts for aviation and marine interests and the general public, maps, statistical data, educational materials, publications, and links to related sites.

265

Rocks and Minerals  

NSDL National Science Digital Library

Rock Cycle Mineralogy 4 Kids Mineralogy 4 kids : rockin Internet site : the best place to learn about rocks and minerals Rock Cycle Map Rocks and Minerals Rocks and Minerals Pictures Rocks and Minerals Slide Show Rocks and Minerals Slide Show Earth Science Earth Science Uses for Minerals Metamorphic Rock Forming Sedimentary Rocks Observation ...

Richrigby

2010-02-23

266

Fossil microorganisms and formation of Early Precambrian weathering crusts  

NASA Astrophysics Data System (ADS)

Weathering crusts are the only reliable evidences of continental conditions existence, and often are the only source of information about exogenous processes and subsequently about conditions under which the development of biosphere occurred. Complex of diverse fossil microorganisms was discovered in result of electronic-microscope investigations. Chemical composition of discovered fossils is identical to that of the host rocks and is represented by Si, Al, Fe, Ca and Mg. Probably, microorganisms fixed in rocks played role of catalyst. Decomposition of minerals, comprising rocks, and their transformation into clayey (argillaceous) minerals, occurred most likely under influence of microorganisms. And may be unique weathering crusts of Early Precambrian were formed due to interaction between specific composition of microorganism assemblage and conditions of hypergene transformations. So it is possible to speak about colonization of land by microbes already at that time and about existence of single raw from weathering crusts (Primitive soils) to real soils.

Astafieva, M. M.; Rozanov, A. Yu.; Vrevsky, A. B.; Alfimova, N. A.; Matrenichev, V. A.; Hoover, R. B.

2009-08-01

267

Strontium Isotopes, Basalt Weathering and Phanerozoic CO2  

NASA Astrophysics Data System (ADS)

Using a combined model for the strontium and carbon cycles that distinguishes the weathering of volcanic and non-volcanic silicate rocks, the weathering of younger and older carbonates, basalt-seawater reaction, and marine carbonate burial, the ratio of volcanic (mainly basalt) weathering to total silicate weathering is calculated as a function of time from the oceanic record of 87Sr/86Sr. The volcanic proportion is then used to modify the equations for calculating atmospheric CO2 in the GEOCARBSULF model by the addition of a new non- dimensional volcanic weathering factor. The effect of uplift and physical erosion on weathering is also modified by using only the distribution over time of the abundance of sandstones and shales, and not Sr isotopic data that had been used previously. Results indicate large variations in the volcanic proportion of silicates undergoing weathering over time and uniformly lower CO2 values than GEOCARBSULF for the early Paleozoic and for the Mesozoic with the degree of lowering depending upon the 87Sr/86Sr of nonvolcanics undergoing weathering and the ratio of the intrinsic weatherability of volcanics to nonvolcanics. An increased minimum in CO2 during the Late Ordovician is in agreement with the presence of a continental glaciation at that time, and, using intrinsic volcanic/non-volcanic weatherability = 10, variations of Jurassic and Cretaceous CO2 agree with the independent work of Fletcher et al (2007) based on liverwort delta 13C values.

Berner, R. A.

2007-12-01

268

Weather and Atmosphere  

NSDL National Science Digital Library

In this unit, students learn the basics about weather and the atmosphere. They investigate materials engineering as it applies to weather and the choices available to us for clothing to counteract the effects of weather. Students have the opportunity to design and analyze combinations of materials for use in specific weather conditions. In the next lesson, students also are introduced to air masses and weather forecasting instrumentation and how engineers work to improve these instruments for atmospheric measurements on Earth and in space. Then, students learn the distinguishing features of the four main types of weather fronts that accompany high and low pressure air masses and how those fronts are depicted on a weather map. During this specific lesson, students learn different ways that engineers help with storm prediction, analysis and protection. In the final lesson, students consider how weather forecasting plays an important part in their daily lives by learning about the history of weather forecasting and how improvements in weather technology have saved lives by providing advance warning of natural disasters.

Integrated Teaching And Learning Program

269

Cenozoic weathering covers in Buchan, Scotland and their significance  

Microsoft Academic Search

Isolated occurrences of chemically weathered rock or saprolite are common in many formerly glaciated areas around the North Atlantic1-6. These pockets of saprolite are widely regarded as remnants of Cenozoic deep-weathering covers which existed before the first extensive Northern Hemisphere glaciations at ~2.4 Myr (ref. 7) and their apparent survival has long been used as evidence for the local ineffectiveness

A. M. Hall

1985-01-01

270

Reply to the comments on [open quotes]Weathering, plants, and the long-term carbon cycle[close quotes  

Microsoft Academic Search

Some lichens can and do promote the weathering of their substrates. The authors' sole interest for purposes of carbon-cycle modeling is the degree of that enhancement for calcium and magnesium silicates relative to both abiotic chemical weathering due to water-rock interaction and the weathering that occurs beneath higher plants. The work by Jackson and Keller (1970) had offered the most

M. F. Cochran; R. A. Berner

1993-01-01

271

Weathering and slope movements in the Calabrian Arc (southern Italy): a state-of-the-art report  

Microsoft Academic Search

Weathered igneous and metamorphic rocks widely crop out in the Mediterranean area, where in recent years greater attention has been paid to weathering-related slope movements. Calabria, the southern-most region of the Italian peninsula, is one of the most challenging area where to study this topic. Many factors favoured during past times the onset and devlopment of the weathering processes in

D. Calcaterra; M. Parise

2003-01-01

272

Methods for the study of rock-inhabiting microorganisms—A mini review  

Microsoft Academic Search

The breakdown (‘weathering’) of rocks is a well-known phenomenon which is not only caused by weather factors such as temperature changes, wind erosion, freezing and thawing, extraction by rain and snow melt water, but also by chemical pollution (acid rain) and microbial activities. Microorganisms are found on the rock surfaces, in cracks and in some cases even within the pore

P. Hirsch; F. E. W. Eckhardt; R PALMERJR

1995-01-01

273

Chemical weathering and boulder mantles, Kärkevagge, Swedish Lapland  

NASA Astrophysics Data System (ADS)

A deposit of giant boulders covers much of the floor of Kärkevagge, an alpine valley in the Swedish Arctic. These mica schist and garnet-mica schist boulders apparently have been there since the waning stages of glaciation in the valley, about 13,000 to 9000 years ago according to cosmogenic dating. Boulder elevations range from 665 to 825 m asl, with the higher and possibly younger boulders situated farther up the valley. We used total chemical analyses of rock and incipient soils forming on the boulders to determine relative weathering intensity on the tops of 20 boulders arrayed across lower, middle, and upper valley positions. An additional three boulders from a deposit of giant boulders damming Lake Rissajaure at the valley head were also analyzed. The dam may be a later deposit, as indicated by preliminary cosmogenic dates, or may be part of the larger valley deposit as other interpretations surmise. Total chemistry was not significantly different between the mica schist and garnet-mica schist boulders. However, total chemistry did vary by position. Boulders at the lowest positions were chemically more similar to those at the dam than to the other positions. This difference was removed when calculating the overall weathering indices by taking the ratio of weathering indices of the C horizon to exposed rock. A clear trend in the weathering was revealed by the analyses: lower valley boulders show significantly more weathering than the upper group and the middle group is intermediate. This indicates that weathering rates differ because of elevation or age of the boulders strewn down the valley. However, boulders on the Lake Rissajaure dam complicate those simple interpretations because they show as much weathering evidence as the lower boulders. All of the weathering indices exhibited this same trend. Elevated levels of Fe in the two more weathered positions indicate influence of pyrite, a known weathering accelerant, and undoubtedly the factor controlling boulder weathering in Kärkevagge.

Darmody, R. G.; Thorn, C. E.; Allen, C. E.

2005-04-01

274

Art Rocks with Rock Art!  

ERIC Educational Resources Information Center

|This article discusses rock art which was the very first "art." Rock art, such as the images created on the stone surfaces of the caves of Lascaux and Altimira, is the true origin of the canvas, paintbrush, and painting media. For there, within caverns deep in the earth, the first artists mixed animal fat, urine, and saliva with powdered minerals…

Bickett, Marianne

2011-01-01

275

NOAA Daily Weather Maps  

NSDL National Science Digital Library

The charts on this website are the principal charts of the former Weather Bureau publication, "Daily Weather Map." They are the Surface Weather Map, the 500-Millibar Height Contours chart, the Highest and Lowest Temperatures chart, and the Precipitation Areas and Amounts chart. For each day, simple charts are arranged on a single page. These charts are the surface analysis of pressure and fronts, color shading, in ten degree intervals,of maximum and minimum temperature, 500-Millibar height contours, and color shaded 24-hour total precipitation. These charts act as links to their respective Daily Weather Map charts. All charts are derived from the operational weather maps prepared at the National Centers for Environmental Prediction, Hydrometeorological Prediction Center, National Weather Service.

Center, Hydrometeorological P.

2011-01-01

276

Watching the World's Weather  

NASA Astrophysics Data System (ADS)

At a time of growing concern about the impact of pollution on the global climate, weather satellites will play an increasingly crucial role in monitoring how changes such as the ozone hole and global warming will affect the world's climate. The complexities of the global weather machine on every scale are attractively revealed through spectacular images of satellite photography. Anyone interested in how the weather satellite works now and in the future should buy this book.

Burroughs, William James

1991-04-01

277

Space Weather Media Viewer  

NSDL National Science Digital Library

This is version 3 of the space Weather Media Viewer, created to work with the space Weather Action Center to see near-real time data and to provide additional images and resources available for educational use. It features easy downloads that can also be added to news reports and space weather reports. It was designed for ease in adding any media (videos, images) data.

2011-01-01

278

Plymouth State Weather Center  

NSDL National Science Digital Library

The Plymouth State Weather Center offers the latest observations and forecasts for the United States and Southern Canada. By simply selecting a state, individuals can find data on the temperature, wind direction and speed, cloud cover, and other weather information for stations throughout the selected region. The website provides a state forecast as well. The map on the homepage allows users to observe the overall weather patterns throughout the continental United States and Southern Canada.

279

National Weather Service  

NSDL National Science Digital Library

Sick and tired of the heat? Feel like it will never end? Then check out the National Weather Service's (NWS) Heat Wave, a site devoted to the extreme weather that is crippling the south. The NWS provides information on the heat index, heat's affect on the body, and how to beat the heat. For those who want an up-to-the-minute look at the weather, the site links to current conditions, forecasts, and watches and warnings.

280

Space Weather: Welcome, SEC  

NSDL National Science Digital Library

This video presentation welcomes the Space Environment Center (SEC) to the National Weather Service (NWS) as an operational entity of the National Centers for Environmental Prediction (NCEP) family. Describing the ways in which space weather affects global communications and power resources, it demonstrates the importance of space weather forecasting as a part of the NWS family of services. With the inclusion of SEC, the NWS now provides environmental understanding from the sun to the sea.

Spangler, Tim

2005-01-11

281

Backyard Weather Stations  

NSDL National Science Digital Library

Learn how to build your own backyard weather station with complete directions provided by FamilyEducation.com's Web site, Backyard Weather Stations. The site shows exactly what you'll need and how to build the necessary components (e.g., rain gauge and barometer), as well as how to keep records of the data collected. Parents and teachers will enjoy watching the kids "learn the basics of scientific observation and record-keeping while satisfying their natural curiosity about weather."

Randall, Dennis.

282

Weather and Climate Data  

NSDL National Science Digital Library

The Weather and Climate Data site for the Center for Ocean-Land-Atmosphere Studies (COLA) contains analyses of current conditions and the state of the atmosphere; weather forecasts; metropolitan quick-look weather summaries and meteograms; short-term climate outlooks for temperature, precipitation and soil moisture; El Nino forecasts for understanding the ocean-atmosphere system; and maximum potential hurricane intensity maps showing potential minimum pressure and potential maximum winds for the oceans.

283

Questa Baseline and Pre-mining Ground-Water Quality Investigation, 7. A Pictorial Record of Chemical Weathering, Erosional Processes, and Potential Debris-flow Hazards in Scar Areas Developed on Hydrothermally Altered Rocks  

USGS Publications Warehouse

Erosional scar areas developed along the lower Red River basin, New Mexico, reveal a complex natural history of mineralizing processes, rapid chemical weathering, and intense physical erosion during periodic outbursts of destructive, storm-induced runoff events. The scar areas are prominent erosional features with craggy headwalls and steep, denuded slopes. The largest scar areas, including, from east to west, Hottentot Creek, Straight Creek, Hansen Creek, Lower Hansen Creek, Sulfur Gulch, and Goat Hill Gulch, head along high east-west trending ridges that form the northern and southern boundaries of the lower Red River basin. Smaller, topographically lower scar areas are developed on ridge noses in the inner Red River valley. Several of the natural scar areas have been modified substantially as a result of large-scale open-pit and underground mining at the Questa Mine; for example, much of the Sulfur Gulch scar was removed by open pit mining, and several scars are now partially or completely covered by mine waste dumps.

Plumlee, Geoffrey S.; Ludington, Steve; Vincent, Kirk R.; Verplanck, Philip L.; Caine, Jonathan S.; Livo, K. Eric

2009-01-01

284

Winter Storm (weather)  

NSDL National Science Digital Library

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. First think about these questions: 1. What is your favorite aspect of winter weather? 2. How does the weather effect your everyday life? Form groups of THREE. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper... 1. In general, when are winds formed? 2. When winds are blowing, how can you ...

Miller, Aubree

2009-09-28

285

Iron isotopic fractionation during continental weathering  

SciTech Connect

The biological activity on continents and the oxygen content of the atmosphere determine the chemical pathways through which Fe is processed at the Earth's surface. Experiments have shown that the relevant chemical pathways fractionate Fe isotopes. Measurements of soils, streams, and deep-sea clay indicate that the {sup 56}Fe/{sup 54}Fe ratio ({delta}{sup 56}Fe relative to igneous rocks) varies from +1{per_thousand} for weathering residues like soils and clays, to -3{per_thousand} for dissolved Fe in streams. These measurements confirm that weathering processes produce substantial fractionation of Fe isotopes in the modern oxidizing Earth surface environment. The results imply that biologically-mediated processes, which preferentially mobilize light Fe isotopes, are critical to Fe chemistry in weathering environments, and that the {delta}{sup 56}Fe of marine dissolved Fe should be variable and negative. Diagenetic reduction of Fe in marine sediments may also be a significant component of the global Fe isotope cycle. Iron isotopes provide a tracer for the influence of biological activity and oxygen in weathering processes through Earth history. Iron isotopic fractionation during weathering may have been smaller or absent in an oxygen-poor environment such as that of the early Precambrian Earth.

Fantle, Matthew S.; DePaolo, Donald J.

2003-10-01

286

Rock Shots  

NSDL National Science Digital Library

Recently debuted on Adam Curry's METAVERSE site is Rock Shots, the first exclusive gallery of Rock 'n Roll photography on the Web by photographer Niels Van Iperen. Niels has been shooting musicians, fans and festivals for over 12 years in Europe and the U.S. His clients include the magazines Rolling Stone, Musician, Metal Hammer, OOR and Guitar World . Rock Shots brings you face to face with Aerosmith live in Brazil, Pearl Jam in their dressing room, the Red Hot Chili Peppers in a swimming pool and more ... on stage, backstage and audience rage. Portraits are viewed in Rock Shots through a custom-made search engine and is updated weekly with new artists.

Iperen, Niels V.

1995-01-01

287

Particle size distributions, microstructures and chemistry of fault rocks in a shallow borehole adjacent to the San Andreas Fault near Little Rock, CA  

Microsoft Academic Search

In mapping the distribution of fractured crystalline rocks along the Mojave section of the San Andreas Fault (SAF), Dor et al. (2006) found that almost all rocks within 50 to 200 m from the fault are pulverized to some degree. In an effort to characterize the role of surface weathering, and quantify the mesoscale and microscale deformation of these rocks

N. Wechsler; J. S. Chester; T. K. Rockwell; Y. Ben-Zion

2009-01-01

288

Weather and emotional state  

NASA Astrophysics Data System (ADS)

Introduction Given the proven effects of weather on the human organism, an attempt to examine its effects on a psychic and emotional level has been made. Emotions affect the bio-tonus, working ability and concentration, hence their significance in various domains of economic life, such as health care, education, transportation, tourism, etc. Data and methods The research has been made in Sofia City within a period of 8 months, using 5 psychological methods (Eysenck Personality Questionnaire (EPQ), State-Trait Anxiety Inventory (STAI), Test for Self-assessment of the emotional state (developed by Wessman and Ricks), Test for evaluation of moods and Test "Self-confidence - Activity - Mood" (developed by the specialists from the Military Academy in Saint Petersburg). The Fiodorov-Chubukov's complex-climatic method was used to characterize meteorological conditions because of the purpose to include in the analysis a maximal number of meteorological elements. 16 weather types are defined in dependence of the meteorological elements values according to this method. Abrupt weather changes from one day to another, defined by the same method, were considered as well. Results and discussions The results obtained by t-test show that the different categories of weather lead to changes in the emotional status, which indicates a character either positive or negative for the organism. The abrupt weather changes, according to expectations, have negative effect on human emotions but only when a transition to the cloudy weather or weather type, classified as "unfavourable" has been realized. The relationship between weather and human emotions is rather complicated since it depends on individual characteristics of people. One of these individual psychological characteristics, marked by the dimension "neuroticism", has a strong effect on emotional reactions in different weather conditions. Emotionally stable individuals are more "protected" to the weather influence on their emotions, while those who are emotionally unstable have a stronger dependence to the impacts of the weather.

Spasova, Z.

2010-09-01

289

A visual analytical approach to rock art panel condition assessment  

NASA Astrophysics Data System (ADS)

Rock art is a term for pecked, scratched, or painted symbols found on rock surfaces, most typically joint faces called rock art panels. Because rock art exists on rock at the atmosphere interface, it is highly susceptible to the destructive processes of weathering. Thus, rock weathering scientists, including those that study both natural and cultural surfaces, play a key role towards understanding rock art longevity. The mapping of weathering forms on rock art panels serves as a basis from which to assess overall panel instability. This work examines fissures, case hardened surfaces, crumbly disintegration, and lichen. Knowledge of instability, as measured through these and other weathering forms, provides integral information to land managers and archaeological conservators required to prioritize panels for remedial action. The work is divided into five chapters, three of which are going to be submitted as a peer-reviewed journal manuscript. The second chapter, written as a manuscript for International Newsletter on Rock Art, describes a specific set of criteria that lead to the development of a mapping tool for weathering forms, called 'mapping weathering forms in three dimensions' (MapWeF). The third chapter, written as a manuscript for Remote Sensing of Environment, presents the methodology used to develop MapWeF. The chapter incorporates terrestrial laser scanning, a geographic information system (GIS), geovisualization, image analysis, and exploratory spatial data analysis (ESDA) to identify, map, and quantify weathering features known to cause instability on rock art panels. The methodology implemented in the third chapter satisfies the criteria described in Chapter Two. In the fourth chapter, prepared as a manuscript for Geomorphology, MapWeF is applied to a site management case study, focusing on a region---southeastern Colorado---with notoriously weak and endangered sandstone rock art panels. The final conclusions chapter describes contributions of the work to GIScience and rock weathering, and discusses how MapWeF, as a diagnostic tool, fits into a larger national vision by linking existing rock art stability characterizations to cultural resource management-related conservation action.

Vogt, Brandon J.

290

Rock varnish as a habitat for extant life on Mars  

Microsoft Academic Search

Many of the rocks on the surface of Mars that have been imaged by the Viking and Mars Pathfinder Landers display dark shiny surface coatings resembling Mn-rich terrestrial rock varnish. On our planet, these thin (5 um - 1 mm) coatings can be the result of a combination of various weathering processes combined with microbial precipitation of mineral oxides over

Barry E. DiGregorio

2002-01-01

291

Oxygen and hydrogen isotope studies of plutonic granitic rocks  

Microsoft Academic Search

The primary deltaD values of the biotites and hornblendes in granitic batholiths are remarkably constant at about -50 to -85, identical to the values in regional metamorphic rocks, marine sediments and greenstones, and most weathering products in temperate climates. Therefore the primary water in these igneous rocks is probably not ``juvenile'', but is ultimately derived by dehydration and\\/or partial melting

Hugh P. Taylor

1978-01-01

292

On Observing the Weather  

ERIC Educational Resources Information Center

|Rain, sun, snow, sleet, wind... the weather affects everyone in some way every day, and observing weather is a terrific activity to attune children to the natural world. It is also a great way for children to practice skills in gathering and recording information and to learn how to use simple tools in a standardized fashion. What better way to…

Crane, Peter

2004-01-01

293

Weather Fundamentals: Clouds. [Videotape].  

ERIC Educational Resources Information Center

|The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) discusses how clouds form, the different types of clouds, and the important role they play in…

1998

294

On Observing the Weather  

ERIC Educational Resources Information Center

Rain, sun, snow, sleet, wind... the weather affects everyone in some way every day, and observing weather is a terrific activity to attune children to the natural world. It is also a great way for children to practice skills in gathering and recording information and to learn how to use simple tools in a standardized fashion. What better way to…

Crane, Peter

2004-01-01

295

Weathering Database Technology  

ERIC Educational Resources Information Center

Collecting weather data is a traditional part of a meteorology unit at the middle level. However, making connections between the data and weather conditions can be a challenge. One way to make these connections clearer is to enter the data into a database. This allows students to quickly compare different fields of data and recognize which…

Snyder, Robert

2005-01-01

296

Weather Fundamentals: Wind. [Videotape].  

ERIC Educational Resources Information Center

|The videos in this educational series, for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes) describes the roles of the sun, temperature, and air pressure in creating the incredible…

1998

297

The Home Weather Station.  

ERIC Educational Resources Information Center

Described is how an amateur weather observer measures and records temperature and precipitation at a well-equipped, backyard weather station. Directions for building an instrument shelter and a description of the instruments needed for measuring temperature and precipitation are included. (KR)

Steinke, Steven D.

1991-01-01

298

Advanced Aviation Weather Forecasts  

Microsoft Academic Search

n The U.S. air transportation system faces a continuously growing gap between the demand for air transportation and the capacity to meet that demand. Two key obstacles to bridging this gap are traffic delays due to en route severe- weather conditions and airport weather conditions. Lincoln Laboratory has been addressing these traffic delays and related safety problems under the Federal

Marilyn M. Wolfson; David A. Clark

2006-01-01

299

Teacher's Weather Sourcebook.  

ERIC Educational Resources Information Center

|This book is a teaching resource for the study of weather-related phenomena. A "weather unit" is often incorporated into school study because of its importance to our daily lives and because of its potential to cut across disciplinary content. This book consists of two parts. Part I covers the major topics of atmospheric science such as the…

Konvicka, Tom

300

Fabulous Weather Day  

ERIC Educational Resources Information Center

|Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. Students learn how meteorologists collect data about the weather, how they study wind, temperature, precipitation, basic types/characteristics of clouds, and how they forecast. The project helps the students grow in…

Marshall, Candice; Mogil, H. Michael

2007-01-01

301

The Home Weather Station.  

ERIC Educational Resources Information Center

|Described is how an amateur weather observer measures and records temperature and precipitation at a well-equipped, backyard weather station. Directions for building an instrument shelter and a description of the instruments needed for measuring temperature and precipitation are included. (KR)|

Steinke, Steven D.

1991-01-01

302

What Is Space Weather?  

NSDL National Science Digital Library

This resource provides a brief overview of the phenomenon known as space weather, which happens when energetic particles emitted by the Sun impact the Earth's magnetosphere. Users can view images, video clips, and animations of auroras and other types of space weather. A set of links to related websites is also provided.

303

Northwest Weather Watch  

NSDL National Science Digital Library

This educational module is designed to teach students about predicting weather. This includes a series of activites about clouds, moisture, air and rain for students to complete. There are curriculum connections to art, writing and math as well as links for more resources and live weather data.

Palewicz, Sue; Scurlock, Marianne; Edmon, Harry

304

People and Weather.  

ERIC Educational Resources Information Center

|Provides: (1) background information on ways weather influences human lives; (2) activities related to this topic; and (3) a ready-to-copy page with weather trivia. Each activity includes an objective, list of materials needed, recommended age level(s), subject area(s), and instructional strategies. (JN)|

NatureScope, 1985

1985-01-01

305

Weather and Individual Happiness  

Microsoft Academic Search

This paper investigates the influence of weather on happiness. While previous studies have examined climatic influence by comparing the well-being of people living in different regions, this paper focuses on how daily changes in weather affect individuals living in a single location. Our data set consists of 516 days of data on 75 students from Osaka University. Daily information on

Yoshiro Tsutsui

2011-01-01

306

Waste glass weathering  

Microsoft Academic Search

The weathering of glass is reviewed by examining processes that affect the reaction of commercial, historical, natural, and nuclear waste glass under conditions of contact with humid air and slowly dripping water, which may lead to immersion in nearly static solution. Radionuclide release data from weathered glass under conditions that may exist in an unsaturated environment are presented and compared

J. K. Bates; E. C. Buck

1993-01-01

307

Designing a Weather Station  

ERIC Educational Resources Information Center

|The collection and analysis of weather data is crucial to the location of alternate energy systems like solar and wind. This article presents a design challenge that gives students a chance to design a weather station to collect data in advance of a large wind turbine installation. Data analysis is a crucial part of any science or engineering…

Roman, Harry T.

2012-01-01

308

Fabulous Weather Day  

ERIC Educational Resources Information Center

Each year, first graders at Kensington Parkwood Elementary School in Kensington, Maryland, look forward to Fabulous Weather Day. Students learn how meteorologists collect data about the weather, how they study wind, temperature, precipitation, basic types/characteristics of clouds, and how they forecast. The project helps the students grow in…

Marshall, Candice; Mogil, H. Michael

2007-01-01

309

Quantifying rock mass strength degradation in coastal rock cliffs  

NASA Astrophysics Data System (ADS)

Although rock cliffs are generally perceived to evolve through undercutting and cantilever collapse of material, the recent application of high-resolution three-dimensional monitoring techniques has suggested that the volumetric losses recorded from layers above the intertidal zone produce an equally significant contribution to cliff behaviour. It is therefore important to understand the controls on rockfalls in such layers. Here we investigate the progressive influence of subaerial exposure and weathering on the geotechnical properties of the rocks encountered within the geologically complex coastal cliffs of the northeast coast of England, UK. Through a program of continuous in situ monitoring of local environmental and tidal conditions and laboratory rock strength testing, we aim to better quantify the relationships between environmental processes and the geotechnical response of the cliff materials. We have cut fresh (not previously exposed) samples from the three main rock types (sandstone, mudstone and shale) found within the cliff to uniform size, shape and volume, thus minimizing variability and removing previous surface weathering effects. In order to characterise the intact strength of the rocks, we have undertaken unconfined compressive strength and triaxial strength tests using high pressure (400 kN maximum axial load; 64 MPa maximum cell pressure) triaxial testing apparatus. The results outline the peak strength characteristics of the unweathered materials. We then divided the samples of each lithology into different experimental groups. The first set of samples remained in the laboratory at constant temperature and humidity; this group provides our control. Samples from each of the three rock types were located at heights on the cliff face corresponding with the different lithologies: at the base (mudstone), in the mid cliff (shale) and at the top of the cliff (sandstone). This subjected them to the same conditions experienced by the in situ cliff forming materials, which were also monitored using an array of environmental sensors. This experiment forms the basis of a long term investigation into the effects of varying environmental conditions on rock mass strength degradation over time. Ultimately, we aim to develop rock mass strength degradation curves to build a quantitative understanding of the interaction between coastal rock cliff behaviour and environmental processes.

Brain, Matthew; Lim, Michael; Rosser, Nick; Petley, David; Norman, Emma; Barlow, John

2010-05-01

310

Fair weather atmospheric electricity  

NASA Astrophysics Data System (ADS)

Not long after Franklin's iconic studies, an atmospheric electric field was discovered in "fair weather" regions, well away from thunderstorms. The origin of the fair weather field was sought by Lord Kelvin, through development of electrostatic instrumentation and early data logging techniques, but was ultimately explained through the global circuit model of C.T.R. Wilson. In Wilson's model, charge exchanged by disturbed weather electrifies the ionosphere, and returns via a small vertical current density in fair weather regions. New insights into the relevance of fair weather atmospheric electricity to terrestrial and planetary atmospheres are now emerging. For example, there is a possible role of the global circuit current density in atmospheric processes, such as cloud formation. Beyond natural atmospheric processes, a novel practical application is the use of early atmospheric electrostatic investigations to provide quantitative information on past urban air pollution.

Harrison, R. G.

2011-06-01

311

Scholastic: Weather Watch  

NSDL National Science Digital Library

The Weather Watch series of online projects investigates seasonal weather phenomena. Students discover the scientific explanations for these events, and use tools and resources for enhanced research. The Hurricanes project allows students to monitor patterns and plot the progression of hurricanes. The Winter Storms project contains an interactive weather maker allowing students to create different weather patterns by changing factors. A winter storm timeline provides stories of the harshest blizzards that have occurred in the U.S. The Weather Reporters project includes a selection of hands-on science experiments for classroom participation, leading up to sharing results online with students worldwide. Each project provides assessment tools and lesson plan suggestions for educators. Links are provided for additional resources.

312

Weathering-related Slope Instabilities of The Calabrian Arc (italy)  

NASA Astrophysics Data System (ADS)

Weathered igneous and metamorphic rocks widely crop out in the Mediterranean area, where in recent years greater attention has been paid to weathering-related slope movements. Calabria, the southernmost region of the Italian peninsula, is one of the most challenging area where to study such topic. Many factors favoured during past times onset and development of the weathering processes in Calabria: huge geody- namic events, still active today as proved by regional seismicity; high uplifting rate; long history of exposition to weathering agents; aggressive climatic conditions, char- acterized by intense, locally clustered, rainfall. In the late '80s a wide research pro- gramme was started in Calabria with the aim of defining an integrated, multidisci- plinary method, suitable to analyse and interpret both the weathering processes and the related instability phenomena. Two were the main goals of the research: a) the engineering-geological characteristics of weathered terrains; and b) the understanding of typology, mechanisms and triggering causes of mass movements. The research was carried out on several test sites distributed over the Calabrian Arc, a complex chain formed by several massifs (Coastal Chain, Sila, Serre, Poro, Aspromonte), largely made up of crystalline rocks. Choice of the sites was also dictated by the presence of important man-made structures (settlements, dams, tunnels, etc.) and the conse- quent availability of specific geological and geotechnical data. A summary of the re- sults so far obtained in the definition of the weathering characteristics of Calabrian crystalline rocks, in type and frequency of slope movements in weathered materials, and in the understandings of the main relations between weathering and instability as well, is here presented. In general terms, weathering in Calabria shows a complex profile, characterized by pronounced irregularity in the spatial distribution of weath- ered horizons. The latter have been recognized up to a depth of 150-200 m from the ground surface, where only occasionally fresh volumes are present. Mass movements range from slide-flows to rock instabilities, including also deep-seated phenomena. Frequency and activity of slope movements seems to be strictly related to outcropping of the more weathered horizons.

Calcaterra, D.; Parise, M.

313

Mechanics of Sheeting Joints and Spheroidal Weathering (Invited)  

NASA Astrophysics Data System (ADS)

Physical weathering in low-porosity materials, like most crystalline rocks, commonly involves fracture, which increases the surface area that can be accessed by reactive chemicals. Chemical reactions on these surfaces can in turn affect the course of further fracturing. Physical and chemical weathering thus commonly go hand in hand, although one process can dominate the other. Two common products of physical weathering are sheeting joints and spheroidal weathering. Both involve fracturing parallel or subparallel to a nearby surface, but they are distinctly different in several ways. Sheeting joints can achieve dimensions of a couple of hundred meters, typically have radii of curvature of 100m - 1000m, and are bounded on one side by the topographic surface. As the distance from the topographic surface increases, the spacing between sheeting joints generally increases and they become less curved. Neither chemical weathering nor grain-scale effects appear to be consequential in the formation of sheeting joints. In contrast, for spheroidal weathering the individual fractures are roughly grain-sized, form in “shells” with radii of curvature of about 1m, and are bounded on all sides by pre-existing bedrock fractures. As the distance from the bounding surfaces increases, the spacing between fractures generally stays about the same but the “shells” defined by the fractures become more curved. Both chemical weathering and grain-scale cracking accompany spheroidal weathering. The processes of sheeting joint formation and spheroidal weathering have been approached from the perspective of a complete boundary value problem in continuum mechanics, where several factors generally are needed to predict the physical failure of a rock mass, including: (a) the shape of a rock body; (b) the stresses acting on its surface, (c) the body forces within it, and (d) the equations of equilibrium; and (e) the constitutive laws for the material. In the cases of sheeting joint formation and spheroidal weathering, a simpler approach that depends on only four factors can be used to provide insight into the fracture process: (a) the shape of a rock body; (b) the stress distribution parallel to its surface, (c) the body forces within it, and (d) a single equation of equilibrium. This approach indicates that in both cases high compressive stresses parallel to convex bounding surfaces contribute fundamentally to the formation of the fractures. In at least some cases involving sheeting joints, the origin of these stresses is likely to be tectonic. In the case of spheroidal weathering, the compressive stresses are likely to arise from chemical alteration of grains.

Martel, S. J.

2010-12-01

314

Environmental Education Tips: Weather Activities.  

ERIC Educational Resources Information Center

|Provides weather activities including questions, on weather, heating the earth's surface, air, tools of the meteorologist, clouds, humidity, wind, and evaporation. Shows an example of a weather chart activity. (RT)|

Brainard, Audrey H.

1989-01-01

315

Analysis of Preflight Weather Briefings.  

National Technical Information Service (NTIS)

Weather is often cited as a factor in general aviation (GA) accidents and mishaps. The type of weather information requested from, or provided by, automated flight service station (AFSS) specialists is dependent on weather conditions at the time the prefl...

A. M. Hendrix O. V. Prinzo R. Hendrix

2007-01-01

316

Environmental Education Tips: Weather Activities.  

ERIC Educational Resources Information Center

Provides weather activities including questions, on weather, heating the earth's surface, air, tools of the meteorologist, clouds, humidity, wind, and evaporation. Shows an example of a weather chart activity. (RT)

Brainard, Audrey H.

1989-01-01

317

Constraints on the Global-scale Chemical Weathering State of Mars From TES Results Based on Spectral Analysis of Chemically Weathered Basalts  

Microsoft Academic Search

On Earth, subaerially exposed basaltic rocks (from arid-to-tropical regions) develop weathering rinds and rock coatings that affect spectroscopic measurements of their natural surfaces. Similarly, basaltic rocks and basaltic soil particles on Mars may have rinds and coatings that are spectroscopically observable. Thermal emission spectroscopy, because it provides information about the composition and structure of silicate and non-silicate minerals and mineraloids,

J. R. Michalski; M. D. Kraft; T. G. Sharp; P. R. Christensen

2005-01-01

318

Reshaping of sandstone surfaces by cryptoendolithic cyanobacteria: bioalkalization causes chemical weathering in arid landscapes  

Microsoft Academic Search

We report a novel weathering mechanism in South African sandstone formations, where cryptoendolithic cyanobacteria induce weathering by substrate alkalization during photosynthesis. As a result, the upper rock part is loosened and then eroded away by physical forces such as wind, water, trampling. This special type of 'exfoliation' is widely distributed and affects the geomorphology of whole sandstone mountain ranges and

B. Budel; B. Weber; M. Kuhl; H. Pfanz; D. Sultemeyer; D. Wessels

2004-01-01

319

Weathering of the Rio Blanco quartz diorite, Luquillo Mountains, Puerto Rico: Coupling oxidation, dissolution, and fracturing  

Microsoft Academic Search

In the mountainous Rio Icacos watershed in northeastern Puerto Rico, quartz diorite bedrock weathers spheroidally, producing a 0.2–2m thick zone of partially weathered rock layers (?2.5cm thickness each) called rindlets, which form concentric layers around corestones. Spheroidal fracturing has been modeled to occur when a weathering reaction with a positive ?V of reaction builds up elastic strain energy. The rates

Heather L. Buss; Peter B. Sak; Samuel M. Webb; Susan L. Brantley

2008-01-01

320

The coupling of biological iron cycling and mineral weathering during saprolite formation, Luquillo Mountains, Puerto Rico  

Microsoft Academic Search

Corestones of quartz diorite bedrock in the Rio Icacos watershed in Puerto Rico weather spheroidally to form concentric sets of partially weathered rock layers (referred to here as rindlets ) that slowly transform to saprolite. The rindlet zone (0.2-2 m thick) is overlain by saprolite (2-8 m) topped by soil (0.5-1 m). With the objective of understanding interactions between weathering,

H. L. BUSS; M. A. BRUNS; M. J. SCHULTZ; J. MOORE; C. F. MATHUR; S. L. BRANTLEY

2006-01-01

321

The role of chemical weathering in the neutralization of acidic deposition  

Microsoft Academic Search

Chemical weathering of rocks and minerals is a key factor which mitigates acidic deposition and affects water chemistry. It\\u000a supplies cations and alkalinity to the surface water, groundwater, ion-exchange complex, and vegetation in the watershed.\\u000a The kinetics of chemical weathering have not been determined in the field, but based on laboratory experiments, the rate of\\u000a weathering has a fractional order

Jerald L. Schnoor; Werner Stumm

1986-01-01

322

Strong tectonic and weak climatic control of long-term chemical weathering rates  

Microsoft Academic Search

The relationships among climate, physical erosion, and chemical weathering have remained uncertain, because long-term chemical weathering rates have been difficult to measure. Here we show that long-term chemical weathering rates can be measured by combining physical erosion rates, inferred from cosmogenic nuclides, with dissolution loss- es, inferred from the rock-to-soil enrichment of insoluble elements. We used this method to measure

Clifford S. Riebe; James W. Kirchner; Darryl E. Granger; Robert C. Finkel

2001-01-01

323

The Space Weather Reanalysis  

NASA Astrophysics Data System (ADS)

The objective of this project is to generate a complete 11 year space weather representation using physically consistent data-driven space weather models. The project will create a consistent, integrated historical record of the near Earth space environment by coupling observational data from space environmental monitoring systems archived at NGDC with data-driven, physically based numerical models. The resulting product will be an enhanced look at the space environment on consistent grids, time resolution, coordinate systems and containing key fields allowing an interested user to quickly and easily incorporate the impact of the near-Earth space climate in environmentally sensitive models. Currently there are no easily accessible long term climate archives available for the space-weather environment. Just as with terrestrial weather it is crucial to understand both daily weather forecasts as well as long term climate changes, so this project will demonstrate the ability to generate a meaningful and physically derived space weather climatology. The results of this project strongly support the DOD's Environmental Scenario Generator (ESG) project. The ESG project provides tools for intellegent data mining, classification and event detection which could be applied to a historical space-weather database. The two projects together provide a suite of tools for the user interested in modeling the effect of the near-earth space environment. We will present results and methodologies developed during the first two years of effort in the project.

Kihn, E. A.; Ridley, A. J.; Zhizhin, M.

2002-12-01

324

Start a Rock Collection  

NSDL National Science Digital Library

Learners follow a three-step process to start their own rock collection. Learners will collect rocks, record information about each rock on a Rock Chart, observe and sort their rocks, and create a rock display. This activity also includes a book list with resources for rock classification.

History, American M.

2012-06-26

325

Basalt weathering in Central Siberia under permafrost conditions  

Microsoft Academic Search

Chemical weathering of basalts in the Putorana Plateau, Central Siberia, has been studied by combining chemical and mineralogical analysis of solids (rocks, soils, river sediments, and suspended matter) and fluid solution chemistry. Altogether, 70 large and small rivers, 30 soil pore waters and groundwaters and over 30 solids were sampled during July to August 2001. Analysis of multiannual data on

O. S. Pokrovsky; J. Schott; D. I. Kudryavtzev; B. Dupré

2005-01-01

326

Characterization of Bacterial Community Structure on a Weathered Pegmatitic Granite  

Microsoft Academic Search

This study exploited the contrasting major element chemistry of a pegmatitic granite to investigate mineralogical influences on bacterial community structure. Intact crystals of variably weathered muscovite, plagioclase, K-feldspar, and quartz were extracted, together with whole-rock granite. Environmental scanning electron microscopy revealed a diversity of bacterial structures, with rods and cocci clearly visible on surfaces of all mineral types. Bacterial automated

Deirdre B. Gleeson; Nabla M. Kennedy; Nicholas Clipson; Karrie Melville; Geoffrey M. Gadd; Frank P. McDermott

2006-01-01

327

Atomic force microscopy of differential weathering in real time  

Microsoft Academic Search

Differential weathering of a rock sample was observed in-situ using atomic force microscopy (AFM). The sample contained fayalite intergrown with veins of magnetite and serpentine. Analyses consisted of polishing the sample with alumina and recording AFM scans periodically during subsequent exposure to nitric acid. Immediately after polishing, serpentine areas were recessed compared to fayalite and magnetite, which were similar in

J. S. Heaton; R. C. Engstrom

1994-01-01

328

Mineralogy of Natural Basalt Weathering Rinds With Application to Thermal Emission Spectra of Mars  

NASA Astrophysics Data System (ADS)

Mineralogy of Natural Basalt Weathering Rinds With Application to Thermal Emission Spectra of Mars M.D. Kraft, J.R. Michalski, T.G. Sharp, (and P.R. Christensen?) Chemically weathered rocks have been suggested to cover a significant portion of the Martian surface based on orbiter observations, and rocks investigated by the Mars Exploration Rover at the Gusev landing site show evidence of chemical alteration and weathering rinds. To understand remote mineralogical and chemical measurements of altered rock surfaces, whether in situ or from orbit, it is important to understand the general characteristics of weathering rinds (e.g., secondary mineralogy and microstructure in rinds) and how these characteristics affect remote observations. We are investigating a suite of weathered rocks of the Columbia River Basalt Group (CRBG) to identify chemical, mineralogical, and micro-structural changes associated with weathering and determine how these changes influence thermal emission measurements. Preliminary work shows that thermal emission spectra of weathered surfaces can vary substantially from spectra of fresh rocks despite rather low degrees of alteration in weathered surfaces. In rocks studied thus far, the predominant difference between the unweathered rock and weathering rind is an increase in porosity in the rind due to dissolution and/or volume expansion, causing a substantial increase in the volume density of micron-scale cracks. Mineralogical differences are imparted in the rind by the (partial) infilling of cracks by secondary materials that are Si, Al, and Fe-rich. A previous investigation by Colman (1982) showed that secondary silicates in basalt weathering rinds were dominantly X-ray amorphous. High-resolution secondary electron imaging of crack-filling products reveals spheroid-shaped materials, 10s of nm in diameter, which are consistent with short-range order allophane. We are currently performing additional analyses using XRD and TEM to constrain the mineralogy of secondary phases in CRGB weathering rinds, including the crystallinity of secondary silicates. Assessing chemical weathering on Mars may rely largely on the ability to detect and constrain the mineralogy of short-range order silicates, which may be the dominant Martian weathering products. Thermal emission spectroscopic data of Mars, with the detailed understanding that we intend to provide with this study, provides a unique and excellent means of constraining the nature of silicate weathering on Mars.

Kraft, M. D.; Michalski, J. R.; Sharp, T. G.; Christensen, P. R.

2004-12-01

329

Weather and Climate  

NSDL National Science Digital Library

This unit introduces younger students to the concepts of weather and climate. Topics include the structure of the atmosphere, the definitions of weather and climate, and temperature and how it is measured. There are also discussions of heat transfers (radiation, conduction, convection), air pressure, wind, and the Coriolis effect. Other topics include types of storms, larger-scale weather systems such as pressure systems and fronts, and factors (insolation, land-sea breezes, orographic effect) that influence the climate in a given region. A vocabulary list and downloadable, printable student worksheets are provided.

Medina, Philip

330

World Weather Information Service  

NSDL National Science Digital Library

The World Meteorological Organization Web site offers the World Weather Information Service page. Here, visitors will find official weather forecasts and climatological information for selected cities worldwide. Users choose a particular continent and country, and are then presented with a list of various cities they can get information on. This includes the date and time of the current forecast, minimum and maximum temperatures for that day, a general cloud description, and a monthly review of various data for that city. If for nothing else, the site does a good job of providing a very straightforward and easy way to find weather information from hundreds of cities around the globe.

331

Extreme Weather Sourcebook 2001  

NSDL National Science Digital Library

Originally reviewed in the February 26, 1999 Scout Report, the latest version of the National Center for Atmospheric Research (NCAR) Extreme Weather Sourcebook offers easy access to updated data on the economic damage from hurricanes, floods, and tornadoes in the United States and its territories. Time spans for each type of extreme weather vary, with hurricane data covering 1900-99, tornadoes 1950-99, floods 1955-1999, and lightning 1959-1994; however, all damage data are reported in constant 1999 dollars to simplify comparisons. The data are offered by weather event and state by rank or alphabetically.

2001-01-01

332

WeatherTracker  

NSDL National Science Digital Library

WeatherTracker is the ideal desktop application for anyone who always wants to know what the weather outside is like. The temperature, barometric pressure, humidity, winds, and current conditions can be displayed in three different formats, updated hourly for North American Cities. The local forecasts, climate data and near shore marine forecasts can be displayed in other windows and are available for select North American cities. Other cities are limited to temperature and current conditions. WeatherTracker is shareware with a fee of $20.00.

333

From Rocks to Cement. What We Make. Science and Technology Education in Philippine Society.  

ERIC Educational Resources Information Center

This module deals with the materials used in making concrete hollow blocks. Topics discussed include: (1) igneous, metamorphic, and sedimentary rocks; (2) weathering (the process of breaking down rocks) and its effects on rocks; (3) cement; (4) stages in the manufacturing of Portland cement; and (5) the transformation of cement into concrete…

Philippines Univ., Quezon City. Science Education Center.

334

Radiogenic Isotopes in Weathering and Hydrology  

NASA Astrophysics Data System (ADS)

There are a small group of elements that display variations in their isotopic composition, resulting from radioactive decay within minerals over geological timescales. These isotopic variations provide natural fingerprints of rock-water interactions and have been widely utilized in studies of weathering and hydrology. The isotopic systems that have been applied in such studies are dictated by the limited number of radioactive parent-daughter nuclide pairs with half-lives and isotopic abundances that result in measurable differences in daughter isotope ratios among common rocks and minerals. Prior to their application to studies of weathering and hydrology, each of these isotopic systems was utilized in geochronology and petrology. As in the case of their original introduction into geochronology and petrology, isotopic systems with the highest concentrations of daughter isotopes in common rocks and minerals and systems with the largest observed isotopic variations were introduced first and have made the largest impact on our understanding of weathering and hydrologic processes. Although radiogenic isotopes have helped elucidate many important aspects of weathering and hydrology, it is important to note that in almost every case that will be discussed in this chapter, our fundamental understanding of these topics came from studies of variations in the concentrations of major cations and anions. This chapter is a "tools chapter" and thus it will highlight applications of radiogenic isotopes that have added additional insight into a wide spectrum of research areas that are summarized in almost all of the other chapters of this volume.The first applications of radiogenic isotopes to weathering processes were based on studies that sought to understand the effects of chemical weathering on the geochronology of whole-rock samples and geochronologically important minerals (Goldich and Gast, 1966; Dasch, 1969; Blaxland, 1974; Clauer, 1979, 1981; Clauer et al., 1982); as well as on the observation that radiogenic isotopes are sometimes preferentially released compared to nonradiogenic isotopes of the same element during acid leaching of rocks ( Hart and Tilton, 1966; Silver et al., 1984; Erel et al., 1991). A major finding of these investigations was that weathering often results in anomalously young Rb-Sr isochron ages, and discordant Pb-Pb ages. Rubidium is generally retained relative to strontium in whole-rock samples, and in some cases radiogenic strontium and lead are lost preferentially to common strontium and lead from weathered minerals.The most widely utilized of these isotopic systems is Rb-Sr, followed by U-Pb. The K-Ar system is not directly applicable to most studies of rock-water interaction, because argon is a noble gas, and upon release during mineral weathering mixes with atmospheric argon, limiting its usefulness as a tracer in most weathering applications. Argon and other noble gas isotopes have, however, found important applications in hydrology (see Chapter 5.15). Three other isotopic systems commonly used in geochronology and petrology include Sm-Nd, Lu-Hf, and Re-Os. These parent and daughter elements are in very low abundance and concentrated in trace mineral phases. Sm-Nd, Lu-Hf, and Re-Os have been used in a few weathering studies but have not been utilized extensively in investigations of weathering and hydrology.The decay of 87Rb to 87Sr has a half-life of 48.8 Gyr, and this radioactive decay results in natural variability in the 87Sr/86Sr ratio in rubidium-bearing minerals (e.g., Blum, 1995). The trace elements rubidium and strontium are geochemically similar to the major elements potassium and calcium, respectively. Therefore, minerals with high K/Ca ratios develop high 87Sr/86Sr ratios over geologic timescales. Once released into the hydrosphere, strontium retains its isotopic composition without significant fractionation by geochemical or biological processes, and is therefore a good tracer for sources and cycling of calcium. The decay of 235U to 207Pb, 238U to 206Pb, and 232Th to 208Pb hav

Blum, J. D.; Erel, Y.

2003-12-01

335

Classic Rock  

ERIC Educational Resources Information Center

While "early college" programs designed for high-school-age students are beginning to proliferate nationwide, a small New England school has been successfully educating teens for nearly four decades. In this article, the author features Simon's Rock, a small liberal arts college located in the Great Barrington, Massachusetts, that has been…

Beem, Edgar Allen

2004-01-01

336

Rock Censorship  

Microsoft Academic Search

This article discusses the issue of censorship of rock music as it pertains to both collectors and directors of libraries interested in popular music collections. It offers both a brief history of recent censorial events, and factual information regarding the censorship issue. It offers suggestions as to what issues those involved need to be familiar with, what the legal issues

James R. McDonald

1994-01-01

337

Rock Groups  

NSDL National Science Digital Library

In this one-page article Steven Strogatz explains how representing numbers with concrete objects can make calculations less confusing. By using images of rocks, he demystifies concepts such as square numbers, parity, primes, and sums of consecutive numbers. This is the second in Steven's series of 15 articles on the Elements of Math (home page cataloged separately).

Strogatz, Steven

2010-02-07

338

How does weather change?  

NSDL National Science Digital Library

This activity is a field investigation where students gather temperature and weather data in the a.m and p.m. and develop a new, experimental question to predict temperature over the course of the year.

Susan Anderson, Taylors Falls Elementary, Taylors Falls, MN based on an activity from Houghton Mifflin Science Grade 2 Weather Patterns, p. D6.

339

The Weather Calculator  

NSDL National Science Digital Library

This set of conversion tools helps convert units and values for weather data, including temperature, moisture, atmospheric pressure, wind, and other parameters. Formulas are also provided for the conversions.

340

Tombstone Weathering Lab  

NSDL National Science Digital Library

Students work in groups in a cemetery to collect a quantitative and a qualitative measure of the extent of weathering of tombstones and their ages. The data are shared between all students, graphed as scatter plots, and the rate of weathering is estimated. Students write about and then discuss the results, the difference between the quantitative and qualitative measures, and speculate on factors in addition to time that may be important for weathering rate. The exercise ends with each students writing a hypothesis about a factor that influences weathering rate and describing a research project that could test that hypothesis. This activity is aimed at developing an understanding of the scatter in "real data", allowing for practice of team work, and hypothesis generation and testing. Designed for a geomorphology course Has minimal/no quantitative component

Anders, Alison

341

Weather and Climate.  

National Technical Information Service (NTIS)

Recommendations for using space observations of weather and climate to aid in solving earth based problems are given. Special attention was given to: (1) extending useful forecasting capability of space systems, (2) reducing social, economic, and human lo...

1975-01-01

342

Winter Weather FAQs  

MedlinePLUS

... lower your body temperature. What is the best clothing for cold weather? Adults and children should wear: ... coat and shoes several layers of loose-fitting clothing Be sure the outer layer of your clothing ...

343

Weatherization Materials Handbook.  

National Technical Information Service (NTIS)

This handbook provides information on purchasing weatherization products, and is intended for use by Community Action Agencies and other community-based organizations in their energy conservation programs. Product information is given for insulation, stor...

1979-01-01

344

Experimentation with Weather Control.  

National Technical Information Service (NTIS)

Contents: Brief historical sketch (woes of citizens as a source of inspiration for, and a cause of difficulties in, weather control experimentation); Three consecutive hail-prevention experiments in Switzerland. Reports of the U.S. National Academy of Sci...

J. Neyman

1967-01-01

345

Winter Weather Emergencies  

MedlinePLUS

... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. You should have a disaster plan. Being prepared can help reduce fear, anxiety and losses. Centers for Disease Control and Prevention

346

Mapping Weather Severity Zones.  

National Technical Information Service (NTIS)

The goals of this project were to develop a methodology to map winter severity from a winter maintenance perspective, and to create electronic maps and associated geospatial data depicting winter weather severity across the country. Work performed under t...

J. J. Mewes

2011-01-01

347

Lithium Isotope History of Cenozoic Seawater: Changes in Silicate Weathering, Reverse Weathering and Seawater Chemistry  

NASA Astrophysics Data System (ADS)

Weathering of continental rocks consumes CO2 and modulates cation fluxes to the ocean, playing a critical role in controlling both long-term seawater chemistry and climate. There are few archives of seawater chemistry that reveal shifts in global tectonic forces that connect Earth-Ocean-Climate processes. We present the first high-resolution 68 Myr record of Li isotopes in seawater (?7LiSW) reconstructed from planktonic forams. From the mid Paleocene (60Ma) to Holocene, ?7LiSW rose 9%, requiring large changes in continental weathering and seafloor reverse weathering fluxes. This scenario is consistent with increased tectonic uplift, more rapid continental denudation, increasingly incongruent continental weathering (lower weathering intensity), decreased dissolved-Li flux and rapid CO2 drawdown. The ?7LiSW today (31.0%, ?Li~1.5 Ma) reflects a balance between inputs of river dissolved Li (?7LiRiv~23%) and hydrothermal Li (?7LiHT~8.4%) and large fractionation (?SW-SED -15%) during removal of LiSW into marine authigenic clays (?7LiSED~16%). Thus a geologic record of ?7LiSW change, unlike 87/86SrSW, is sensitive to the large Li-isotope fractionation factors and to changes in silicate sources and sinks. ?7LiSW today is heavier than either upper continental crust (?7LiUCC =1.7%) or oceanic basalts (?7LiBasalt =3.4%) due to 6Li enrichment in the secondary clays formed during chemical weathering and to preferential 6Li-uptake during seafloor reverse weathering - the "push-me pull-you" systematics of ?7LiSW balance. The stepped increases in ?7LiSW accumulating to 9% over 60 Ma are coincident with major tectonic uplifts, large igneous province (LIP) eruptions, and global climate cooling events. With increased mountain building and changes in continental silicate weathering regimes over the Cenozoic, the isotopic signature of ?7LiRiv increased from 2% to 23%, and the dissolved Li river flux fell by 50%. This scenario requires that the total silicate-derived cation river flux to the ocean (dissolved plus clay-bound) increased, so that the uplift- and weathering-driven cooling of the climate shifted the global weathering pattern from transport limited to weathering limited, increasing secondary clay mineral formation. As a result of preferential retention of 6Li by secondary clays, ?7LiRiv became heavier, driving ?7LiSW to its current heavy value.

Misra, S.; Froelich, P. N.

2011-12-01

348

Microbial Weathering of Peridotites by a Tropical Cyanobacterial Mat  

NASA Astrophysics Data System (ADS)

Nickeliferous tropical laterites represent more than 60 percent of the worlds Ni reserves and are believed to be the product of millions of years of weathering on ultramafic peridotite rocks in tropical regions. While both Cyanobacterial mats and microbial weathering processes are well characterized in general, these structures have never been implicated in ultramafic rock weathering. We used Au/Hg amalgam voltammetric microelectrodes to measure several important dissolved redox-active species (Fe (II), Mn (II), oxygen, peroxide, and organo-Fe/Mn complexes) in situ. Dissolved Fe II/III, phosphate, nitrite, nitrate and electrical conductivity, pH, & Eh were measured on site by spectrophotometry and combination electrodes, respectively. Mat, rock and water samples were compared using a suite of analytical techniques (XRD, SIMS, XPS, ICP-MS). Microbial community structure was determined using ESEM and 16S rDNA cloning. In order to further investigate the relative importance of peroxide and organic ligands (e.g. DFAM) on weathering, laboratory incubations, monitored by voltammetry, were also conducted. In situ voltammetric profiles revealed significant redox zonation and the presence of both organo-Mn (III/IV) and organo-Fe(III) complexes within the mat. Importantly, 50 ?M peroxide was detected within 15 mm of the atmosphere/mat interface. The mat was highly enriched in Ni and Mn compared to the substrate. XPS and dynamic SIMS characterization of the rock surface showed trace metal zonation within a weathering rind. Laboratory experiments demonstrated maximal dissolution of Ni and Mn from the substrate in the presence of both peroxide and DFAM. The high peroxide concentrations in the mat are likely produced via a photochemical reaction involving DOC. Microbial successions resulting in the accumulation of organic material allow the development of redox zonation. We propose a mechanism for enhanced weathering of serpentenized peridotites under microaerophilic conditions, by means of a combination of peroxide and bacterially produced organic ligands. This process may be important for the development of nickeliferous laterite deposits.

Fowle, D.; Crowe, S.; O'Neill, A.; Weisener, C.

2006-12-01

349

Predicting Seasonal Weather  

NSDL National Science Digital Library

Large-scale weather patterns which occur in various locations around the Earth play a significant part in controlling the weather on a seasonal time scale. A National Science Foundation (NSF)-funded collaborative research effort between Atmospheric and Environmental Research, Inc. (AER), and the Massachusetts Institute of Technology (MIT) has led to a new understanding of the relationship between fall snow cover and winter climate variability. This research has led to the development of a new seasonal forecast model.

350

Extreme Weather Sourcebook: Tornadoes  

NSDL National Science Digital Library

The Extreme Weather Sourcebook is a database maintained by the Societal Impacts Program (SIP) at NCAR of statistics on extreme weather events. The Sourcebook is intended as a resource for researchers, policy makers, the media, and the general public, among other users. This page from the Sourcebook showcases data on tornado damages as total losses for the years 1950-2009 in the United States.

University Consortium for Atmospheric Research (UCAR)

351

An Ocean of Weather  

NSDL National Science Digital Library

In this lesson, students will investigate the close relationship between the ocean and the atmosphere to determine the extent the ocean affects the Earth's weather in the South Atlantic Bight region. As they study this relationship, students will learn that the ocean and atmosphere work together as a system. They will experiment to find out that heat transfer from the ocean is a cause of much of Earth's weather and will make and explain an ocean water cycle.

352

Effects of paleogeology, chemical weathering, and climate on the global geochemical cycle of carbon dioxide  

Microsoft Academic Search

A new method of geologic reconstruction has been developed that determines areas of exposure for each epoch of the Phanerozoic. The paleogeologic maps reveal that the relative proportions of exposed rock types show few abrupt changes through Phanerozoic time, compared to the secular changes in areal extent of rock deposition. Chemical weathering of silicate minerals acts as a long-term transfer

Bluth; G. J. S

1990-01-01

353

Global CO2-consumption by chemical weathering: What is the contribution of highly active weathering regions?  

NASA Astrophysics Data System (ADS)

CO2-consumption by chemical weathering of silicates and resulting silicate/carbonate weathering ratios influences the terrestrial lateral inorganic carbon flux to the ocean and long-term climate changes. However, little is known of the spatial extension of highly active weathering regions and their proportion of global CO2-consumption. As those regions may be of significant importance for global climate change, global CO2-consumption is calculated here at high resolution, to adequately represent them. In previous studies global CO2-consumption is estimated using two different approaches: i) a reverse approach based on hydrochemical fluxes from large rivers and ii) a forward approach applying spatially explicit a function for CO2-consumption. The first approach results in an estimate without providing a spatial resolution for highly active regions and the second approach applied six lithological classes while including three sediment classes (shale, sandstone and carbonate rock) based at a 1° or 2° grid resolution. It remained uncertain, if the applied lithological classification schemes represent adequately CO2-consumption from sediments on a global scale (as well as liberation of other elements like phosphorus or silicon by chemical weatheirng). This is due to the large variability of sediment properties, their diagenetic history and the contribution from carbonates apparent in silicate dominated lithological classes. To address these issues, a CO2-consumption model, trained at high-resolution data, is applied here to a global vector based lithological map with 15 lithological classes. The calibration data were obtained from areas representing a wide range of weathering rates. Resulting global CO2-consumption by chemical weathering is similar to earlier estimates (237 Mt C a-1) but the proportion of silicate weathering is 63%, and thus larger than previous estimates (49 to 60%). The application of the enhanced lithological classification scheme reveals that it is important to distinguish among the various types of sedimentary rocks and their diagenetic history to evaluate the spatial distribution of rock weathering and thus lateral inorganic carbon fluxes. Results highlight the role of hotspots (>10 times global average weathering rates) and hyperactive areas (5 to 10 times global average rates). Only 9% of the global exorheic area is responsible for about 50% of CO2- consumption by chemical weathering (or if hotspots and hyperactive areas are considered: 3.4% of exorheic surface area corresponds to 28% of global CO2-consumption). The contribution of endorheic areas to the global CO2-consumption is with 3.7 Mt C a-1 only minor. A significant impact on the global CO2-consumption rate can be expected if identified highly active areas are affected by changes in the overall spatial patterns of the hydrological cycle due to ongoing global climate change. Specifically if comparing the Last Glacial Maximum with present conditions it is probable that also the global carbon cycle has been affected by those changes. It is expected that results will contribute to improve global carbon and global circulation models. In addition, recognizing chemical weathering rates and geochemical composition of certain lithological classes may be of value for studies focusing on biological aspects of the carbon cycles (e.g. studies needing information on the abundance of phosphorus or silica in the soil or aquatic system). Reference: Hartmann, J., Kempe, S, Dürr, H.H., Jansen, N. (2009) Global CO2-consumption by chemical weathering: What is the contribution of highly active weathering regions?. Global and Planetary Change, 69, 185-194. doi:10.1016/j.gloplacha.2009.07.007

Hartmann, Jens; Jansen, Nils; Dürr, Hans H.; Kempe, Stephan; Köhler, Peter

2010-05-01

354

Chemical Weathering in the Amur River  

NASA Astrophysics Data System (ADS)

The Amur River is the fourth largest river (~1,855,000 km2) in north Eurasia which flow into the Pacific Ocean. It flows through 4 countries-the Russian Far East, northeast China, east Mongolia and a small territory of North Korea. Climatic and ecological conditions differ significantly from western intercontinental region to eastern coastal area. Southern part of the Amur basin is mostly lowland region with alluvial deposits and various rocks of sedimentary and magmatic origin. In the northern part, there are mountains with siliceous and carbonaceous sedimentary rocks, and permafrost plays an important role in river chemical discharge. We examined dissolved major element and Sr isotopic compositions of 19 summer samples in the middle reach of the Amur to better understand the relationship between chemical weathering, geology, and climate (with the aid of GlS). We found that the 87Sr/86Sr ratios fall a narrow the range of 0.709-0.712 and the TDS (total dissolved solids) is about 80 (40-180) mg/L. Kaolinite is the thermodynamically stable silicate mineral for most samples. We quantified chemical weathering rates using an inverse model: rain accounts for (2-14)% of the total cationic concentration, evaporites (3-19)%, carbonates (43-77)%, and silicates (14-32)%. Net CO2 consumption rate by silicate weathering in the Amur basin is in the range of (10-100) ×103 mol/km2/yr, and the value at the main channel above confluence with the Sungari tributary is ~10 ×103 mol/km2/yr. We tested correlations between the CO2 consumption rates by silicate weathering and various climatic (air temperature, precipitation, and runoff) and geologic (relief, slope, elevation) factors calculated using GIS. Stepwise regression using SPSS on the entire data set yielded best correlation (negative) with elevation (R2 = 0.6823, p = 0.0002).

Moon, S.; Huh, Y.

2006-12-01

355

Mechanical Properties of Rocks.  

National Technical Information Service (NTIS)

Contents: Method of determining the strength of rocks under uniaxial compression; Prophilographic investigations and correct data on mechanical properties of rocks; Methods of determining the shearing strength of rocks; Effect of rock-specimen size on mec...

M. M. Protodyakonov M. I. Koifman

1968-01-01

356

Weather Science, Weather Research: History of Their Problems and Findings from Documents during Three Thousand Years.  

National Technical Information Service (NTIS)

Contents: The prescientific era. Perception of weather; Establishment of the science of weather. Recording the weather in numbers; Extension of the science of weather. Representation of weather: climatic charts and weather charts; Meteorology up to the be...

K. Schneider-Carius

1975-01-01

357

The Influence of Weathering on the Engineering Properties of Dunites  

NASA Astrophysics Data System (ADS)

Weathering processes cause important changes in the engineering properties of rocks. In this study, dunites in the Bursa region in western Turkey were investigated and the changes in engineering properties due to weathering were evaluated. The studies were initiated with field observations including measurement of the characteristics of discontinuities such as spacing, aperture, fill material, roughness, and Schmidt hammer rebound value. Subsequently, laboratory studies were conducted in two stages. The first stage comprised mineralogical, petrographic, and chemical analyses. The second stage included physicomechanical tests to determine specific gravity, unit weights, water absorption, effective porosity, uniaxial compressive strength, P-wave velocity, and slake-durability index. According to these evaluations, the changes in engineering properties were determined to be mostly related to serpentinization at every stage of weathering. The most suitable parameters for characterizing the degree of weathering of the studied dunites are loss-on-ignition values, specific gravity, unit weight, water absorption, and effective porosity.

Ündül, Ömer; Tu?rul, Atiye

2012-03-01

358

Weather and The Water Cycle  

NSDL National Science Digital Library

Students will be able to do activities dealing with weather and water cycles. Learn what makes weather wet and wild, forcast and predict weather. Webweather For Kids Learn about tornadoes and hurricanes. Kidstorm Learn about the water cycles. water Cycles Now click on the following link: Interactive weather maker 1. How much change in temperature is needed to make it snow? On the right side of the page click on Weather Detective Web Quest. Follow the ...

Merritt, Mrs.

2005-10-15

359

Effects of chemical weathering on infrared spectra of Columbia River Basalt and spectral interpretations of martian alteration  

NASA Astrophysics Data System (ADS)

We investigated the mineralogy of basalt weathering rinds and fresh basaltic rocks using visible/near-infrared (VNIR) ( ? = 0.4-2.5 ?m) and thermal emission ( ? = 6-30 ?m) spectroscopy to 1) constrain the effects of chemical weathering on rock spectra, and 2) further understand the context of infrared spectra of Mars, which may contain evidence for weathered rocks and particulates derived from them. VNIR spectra of weathered rock surfaces are generally redder and brighter than fresh surfaces. Thermal infrared spectra of weathered basalts show evidence for aluminous opal and clay minerals (or clay precursor mineraloids) in natural surfaces. Supporting VNIR observations generally do not show the same evidence for neoformed clays or silica because of their textural occurrence as thin coatings and microfracture-fill, and possibly due to poor crystallinity of the aluminosilicate weathering products in this context. Spectral trends observed at Mars, such as the detection of low to moderate (10-25%) abundances of silica and clay that are observed in the thermal infrared but not in the VNIR, are therefore consistent with trends observed for natural rock surfaces in the laboratory. The combined use of thermal infrared and VNIR suggest that vast areas of martian dark regions contain sandy-rocky basaltic materials with weathering rinds and thin coatings that could have formed in conditions of relatively low water/rock ratios.

Michalski, Joseph R.; Kraft, Michael D.; Sharp, Thomas G.; Christensen, Philip R.

2006-08-01

360

Basalt weathering across scales  

NASA Astrophysics Data System (ADS)

Weathering of silicate minerals impacts many geological and ecological processes. For example, the weathering of basalt contributes significantly to consumption of atmospheric carbon dioxide (CO 2) and must be included in global calculations of such consumption over geological timeframes. Here we compare weathering advance rates for basalt ( wD?), where D and ? indicate the scale at which the rate is determined and surface area measured, respectively, from the laboratory to the watershed scales. Data collected at the laboratory, weathering rind, soil profile and watershed scales show that weathering advance rate of basalt is a fractal property that can be described by a fractal dimension ( dr ? 2.3). By combining the fractal description of rates with an Arrhenius relationship for basalt weathering, we derive the following equation to predict weathering advance rates at any spatial scale from weathering advance rates measured at the BET scale: wD?=k(e. Here, k0 is the pre-exponential factor (1.29 × 10 7 mm 3 mm - 2 yr - 1 ), Ea is the activation energy (70 kj mol - 1 ), and a is a spatial constant related to the scale of measurement of BET surface area (10 - 7 mm). The term, (, is the roughness. The roughness fractal dimension can be conceptualized as a factor related to both the thickness of the reaction front and the specific surface area within the reaction front. However, the above equation can also be written in terms of a surface fractal dimension and the hypothetical average grain radius. These fractal dimensions provide insight into reaction front geometry and should vary with lithology. Once the surface area discrepancy has been accounted for using this method, we find a one to two order of magnitude range in weathering advance rates measured at any scale or temperature that can be attributed to factors such as changes in erosional regime, parent lithology, mechanism, climate, composition of reacting fluid, and biological activity. Our scaled equation, when used to predict global basalt CO 2 consumption based upon global lithologic maps, yields an uptake flux (1.75 × 1013 mol CO 2 yr - 1 ) within the predicted error of fluxes estimated based upon riverine measurements.

Navarre-Sitchler, Alexis; Brantley, Susan

2007-09-01

361

Oceans, Climate and Weather  

NSDL National Science Digital Library

What is the difference between weather and climate? What do the oceans have to do with them? Weather is the day-to-day state of the atmosphere and its short-term (minutes to weeks) variation. Climate is typically described by the regional patterns of seasonal temperature and precipitation over 30 years. The averages of annual temperature, rainfall, cloud cover, and depth of frost penetration are all typical climate-related statistics. The oceans influence the worlds climate by storing solar energy and distributing it around the planet through currents and atmospheric winds.This publication is all about developing your students understandings of earths oceans and the major effect they have on climate. Understanding and interpreting local weather data and understanding the relationship between weather and climate are important first steps to understanding larger-scale global climate changes. Activities that ask students to collect and analyze local weather data as well as analyze global data can be found in the Lessons and Activities section. Analyzing and interpreting data is a major focus of this publication. Numerous data sets can be found in the Sources for Real Data section. The Background Information section and the article Tomorrows Forecast will help reinforce your own content knowledge.

Lightle, Kimberly

2006-01-01

362

[Weather, climate and health].  

PubMed

The notion of complex influence of atmospheric conditions on modem human population, especially the relationship between weather, climate and human healths, has actuated the World Meteorological Organisation to commemorate the coming into force, on March 23, 1950, of the Convention of WMO and this year to celebrate this day by focusing on theme of current interest--"Weather, climate and health". In the light of this, the authors of this paper reveal the results of recent studies dealing with influence of sudden and short-term changes in weather and climate on human health, and future expected climate changes due to "greenhouse" effect, increase in global temperature and tropospheric ozone depletion, as well. Special attention is given to climate shifts due to ENSO (El Niño/Southern Oscillation) phenomenon because of its great impact on human society and epidemics of certain infectious diseases. The results of biometeorological studies dealing with complex influence of daily weather changes on incidence of certain diseases in Croatia have also been presented. In addition, the authors have stated their own view and opinion in regard to future biometeorlogical studies in Croatia in order to achieve better understanding of influence of climate and weather changes on human health, and help prevention of mortality and morbidity related to chronic noninfectious diseases. PMID:19658377

Bani?, M; Plesko, N; Plesko, S

363

Phosphine from rocks: mechanically driven phosphate reduction?  

PubMed

Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks. PMID:16294866

Glindemann, Dietmar; Edwards, Marc; Morgenstern, Peter

2005-11-01

364

Effects of climate on chemical weathering in watersheds  

USGS Publications Warehouse

Climatic effects on chemical weathering are evaluated by correlating variations in solute concentrations and fluxes with temperature, precipitation, runoff, and evapotranspiration (ET) for a worldwide distribution of sixty-eight watersheds underlain by granitoid rock types. Stream solute concentrations are strongly correlated with proportional ET loss, and evaporative concentration makes stream solute concentrations an inapprorpiate surrogate for chemical weathering. Chemical fluxes are unaffected by ET, and SiO2 and Na weathering fluxes exhibit systematic increases with precipitation, runoff, and temperature. However, warm and wet watersheds produce anomalously rapid weathering rates. A proposed model that provides an improved prediction of weathering rates over climatic extremes is the product of linear precipitation and Arrhenius temperature functions. The resulting apparent activation energies based on SiO2 and Na fluxes are 59.4 and 62.5 kJ.mol-1, respectively. The coupling between temperature and precipitation emphasizes the importance of tropical regions in global silicate weathering fluxes, and suggests it is not representative to use continental averages for temperature and precipitation in the weathering rate functions of global carbon cycling and climatic change models. Fluxes of K, Ca, and Mg exhibit no climatic correlation, implying that other processes, such as ion exchange, nutrient cycling, and variations in lithology, obscure any climatic signal. -from Authors

White, A. F.; Blum, A. E.

1995-01-01

365

Delicious Differential Weathering  

NSDL National Science Digital Library

Students are asked to place a Baby Ruth candy bar in their mouths but are asked not to bite it. Once they have sucked off all the chocolate and caramel the students are given permission to bite the peanuts. After lecturing on the differences between chemical and physical weathering students are asked to list the order of ingredients they tasted. Each group is given a sample of granite. Students are asked to list three visible minerals in the granite. Relate the minerals of the granite (hornblende, feldspar, and quartz) to the ingredients of the candy bar. Explain Bowen's reaction series and how different minerals will weather first and how climate will affect weathering rates.

Gorte, Mary

366

Extreme Weather Sourcebook  

NSDL National Science Digital Library

This report presents a summary of damage caused by hurricanes, floods, tornadoes, lightning, hail, thunderstorms, and windstorms in the United States and its territories. Information was collected from as far back as 1900 (for hurricanes) and as recently as 1999 (for most categories). For each weather category, there is statistical information on monetary damages (in millions of dollars), sorted by rank and by alphabetic listing. There is also a summary table for composite damage from tornadoes, hurricanes, and floods; tables and graphs for damage and casualties caused by lightning; and summary information for other types of extreme weather (hail, thunderstorms, winter storms). Links are provided to information on data sources and methodology and on the societal impacts of weather.

367

Rock mechanics. Second edition  

SciTech Connect

Rock Mechanics, 2nd Edition deals with rock as an engineering construction material-a material with which, upon which, and within which civil engineers build structures. It thus pertains to hydraulic structures engineering; to highway, railway, canal, foundation, and tunnel engineering; and to all kinds of rock earthworks and to substructures in rock. Major changes in this new edition include: rock classification, rock types and description, rock testing equipment, rock properties, stability effects of discontinuity and gouge, grouting, gunite and shotcrete, and Lugeon's water test. This new edition also covers rock bolting and prestressing, pressure-grouted soil anchors, and rock slope stabilization.

Jumikis, A.R.

1983-01-01

368

Wisconsin Weather Stories  

NSDL National Science Digital Library

University of Wisconsin meteorologists and folklorists along with Wisconsin teachers created this website to offer classroom materials "that integrate earth science, social studies, language arts, and math." Students can learn about severe weather and the importance of forecasting by listening to and reading people's accounts. Each lesson contains benchmarks and standards for grades four, eight, and twelve; as well as many fun activities. The website features a concise glossary and many links where teachers can discover more resources. Visitors who remember the weather discussed, such as the Ice Bowl of 1967, can find out how to submit their accounts to the website.

369

Indigenous Weather Knowledge  

NSDL National Science Digital Library

Produced by the Commonwealth Bureau of Meteorology, this Web site exhibits seasonal weather calendars created by Indigenous people thousands of years ago. The site first discusses the Aboriginal people in Australia and their methods for dealing with past climate changes. Studying the calendars, users will notice that Indigenous people dealt with climate on a local scale and recognized a varying number of seasons. For comparison, the site presents the Bureau of Meteorology's Temperature and Rainfall Graphs and climate group classification maps. Because it is still in the early stages of development, users should revisit this site to learn more about Aboriginal knowledge of weather and climate.

370

Wonderful World of Weather  

NSDL National Science Digital Library

This standards-based module uses hands-on activities and real-time data investigations to allow students in the elementary grades to investigate weather phenomena both locally as well as in other places around the world. By using hands-on activities and real-time data investigations, the students will develop a basic understanding of how weather can be described in measurable quantities, such as temperature, wind and precipitation. The lesson plans which make up this module have been designed to allow teachers to select the ones which fit into their curriculum to allow for flexibility in implementation

2003-01-01

371

Space weather in Japan  

NASA Astrophysics Data System (ADS)

In Japan, Communications Research Laboratory engages in operational space environment information service as National Forecasting Center and Regional Warning Center of ISES. Data of local observation and data collected via internet from domestic and foreign institute are used for daily operational forecast. Fundamental research on space weather issue has been carried out at several institutes and university, including STE Laboratory and NASDA. In this presentation, overview of current space weather forecast operation and system for information outreach in Japan will be presented. Current and future observation program from ground-base and space will be also briefly reviewed.

Akioka, M.

372

Space weather in Japan  

NASA Astrophysics Data System (ADS)

In Japan, Communications Research Laboratory engages in operational space environment information services as National Forecasting Center and Regional Warning Center of ISES. Data from local observations and data collected via internet from domestic and foreign institutes are used for the daily operational forecast. Fundamental research on space weather issues has been carried out at several institutes and universities, including STE Laboratory and NASDA. In this presentation, an overview of current space weather forecast operations and a system for information outreach in Japan will be presented. Current and future observation programs from ground-base and space will be also briefly reviewed.

Akioka, M.; Ishibashi, H.; Kikuchi, T.; Sagawa, E.; Nagatsuma, T.

373

Space Weather Action Center  

NSDL National Science Digital Library

In this interdisciplinary activity, learners create a Space Weather Action Center (SWAC) to monitor solar storms and develop real SWAC news reports. Learners work in teams to first investigate sunspot regions, storm signals, a magnetosphere, and auroras and share their research with their peers. Then, learners assemble an instructional flip chart, data collection clipboards/notebook, and display board for their SWAC. Learners conclude the activity by writing their own weather reports, which can be filmed or broadcast if equipment is available. Once learners create a SWAC, solar storm research and reporting can become an ongoing activity.

Nasa

2013-07-30

374

Olympian weather forecasting  

NASA Astrophysics Data System (ADS)

A unique public-private partnership will provide detailed weather information at the 2002 Winter Olympics in Utah, 8-24 February About 50 meteorologists with the National Weather Service (NWS) and several private groups will work in the background to provide accurate forecasts.This is the first time that U.S. government and private meteorologists will share forecasting responsibilities for the Olympics, according to the Salt Lake Organizing Committee for the Olympic Games. The partnership includes meteorologists with the University of Utah and KSL-TV in Salt Lake City.

Showstack, Randy

375

Weather and The Seasons  

NSDL National Science Digital Library

This project will allow students to see the different weather conditions that are apart of the different seasons. It will also help students to identify the characterisitics that go along with each of the different seasons, For example, what weather conditions are present in each season and how we dress for each season. With a partner watch the video: Observing Clouds On piece of paper write your answers to the following questions: 1). What types of changes in the clouds did you observe? 2). What do you think caused the changes in the clouds? (Ex: teperature, morning to night, etc) Next, with your partner, please watch the second video: Observing Precipitation On ...

Maxwell, Ms.

2012-02-07

376

Initial effects of vegetation on Hawaiian basalt weathering rates  

SciTech Connect

Weathering of Ca and Mg silicates on land and ensuing precipitation and burial of Ca and Mg carbonates in marine sediments is the principal sink for carbon dioxide from the atmosphere/ocean system on geologic time scales. Model calculations of ancient atmospheric CO[sub 2] partial pressure depend strongly on the authors assumptions about the enhancement of silicate weathering rates first by primitive terrestrial biota, then by the appearance and evolution of the vascular plants. Aa and pahoehoe basalts were collected from Mauna Loa and Kilauea volcanoes on the island of Hawaii. Flows ranged in age (one year to several thousand years) and in ambient climate. Where possible, each flow was sampled beneath a suite of current plant covers: none, lichens, and higher plants. Rocks were embedded in epoxy to preserve the plant-rock interface, then sectioned and subjected to electron probe microanalysis. During initial weathering, vascular plants appeared to promote congruent dissolution of minerals (particularly olivine and Ca-rich plagioclase) and glass near the surfaces of underlying basalts. In the neighborhood of roots, primary cracks widened with time into networks of open channels. This effect was observed prior to the formation of measurable leached zones in exterior grains and prior to the appearance of secondary minerals. As a result, initial mass loss from young, plant-covered basalts appeared to be up to one or more orders of magnitude greater than from bare-rock controls. Despite earlier reports of substantial enhancement of Hawaiian basalt weathering rates by the lichen Stereocaulon vulcani, weathering observed beneath this lichen was comparable to that of unvegetated rocks.

Cochran, M.F.; Berner, R.A. (Yale Univ., New Haven, CT (United States))

1992-01-01

377

Edible Rocks  

NSDL National Science Digital Library

This lesson has been designed as a comfortable introduction to describing meteorites. It helps students become better observers by making a connection between the familiar (candy bars) and the unfamiliar (meteorites). Edible "rocks" are used in a scientific context, showing students the importance of observation, teamwork and communication skills. In everyday terms, students draw and describe the food. They pair their observations with short descriptions that are in geologic "Field Note" style. As the teacher and class review, appropriate geologic terminology may be substituted by the teacher and subsequently embraced by even very young students.

Lindstrom, Marilyn

378

Rock Showdown  

NSDL National Science Digital Library

Service learning is a pedagogy that has the potential to connect young adolescents with their community in authentic situations where they can initiate projects that address real needs. The use of the "community" as a context for service and learning has long been explored in science education. There are many examples of service learning initiatives which generally fall under the heading of community-based education . In most cases, students carry out service projects for the community, and along the way may learn some science. By contrast, seventh-grade students from Philippine Science High School created the Rock Showdown as a model of service learning in partnership with the community.

Laroder, Aris; Tippins, Deborah; Morano, Lourdes; Handa, Vicente

2007-03-01

379

Weather Depot 1.21  

NSDL National Science Digital Library

As a quote commonly misattributed to Mark Twain goes, "Everyone talks about the weather, but no one does a thing about it." This little program from the folks at Weather Depot won't allow users to modify weather conditions, but it will let users customize their own weather planner (with hourly and daily updates), view regional radar, and view a map of current temperatures around the United States. Additionally, users may look up current road conditions, and view weather Web cams. Weather Depot 1.21 is compatible with all systems running Windows 98 and higher.

380

Nitrogen fixation in lichens is important for improved rock weathering.  

PubMed

It is known that cyanobacteria in cyanolichens fix nitrogen for their nutrition.However, specific uses of the fixed nitrogen have not been examined. The present study shows experimentally that a mutualistic interaction between a heterotrophic N2 fixer and lichen fungi in the presence of a carbon source can contribute to enhanced release of organic acids, leading to improved solubilization of the mineral substrate. Three lichen fungi were isolated from Xanthoparmelia mexicana, a foliose lichen, and they were cultured separately or with a heterotrophic N2 fixer in nutrient broth media in the presence of a mineral substrate. Cells of the N2-fixing bacteria attached to the mycelial mats of all fungi, forming biofilms. All biofilms showed higher solubilizations of the substrate than cultures of their fungi alone. This finding has bearing on the significance of the origin and existence of N2-fixing activity in the evolution of lichen symbiosis. Further, our results may explain why there are N2-fixing photobionts even in the presence of non- fixing photobionts (green algae) in some remarkable lichens such as Placopsis gelida. Our study sheds doubt on the idea that the establishment of terrestrial eukaryotes was possible only through the association between a fungus and a phototroph. PMID:17301502

Seneviratne, Gamini; Indrasena, I K

2006-12-01

381

Brazilian Space Weather Program  

Microsoft Academic Search

A space weather program is being initiated at the Brazilian National Institute for Space Research (INPE) to study events from their initiation on the sun to their impacts on the earth, including their effects on space-based and ground-based technological systems. The program is built on existing capabilities at INPE, which include scientists with a long tradition and excellence in the

Antonio Padilha; Hisao Takahashi; Eurico de Paula; Hanumant Sawant; Haroldo de Campos Velho; Icaro Vitorello; Joaquim Costa; Jonas Souza; José Cecatto; Odim Mendes; Walter Demétrio Gonzalez Alarcon

2008-01-01

382

What Makes the Weather?  

ERIC Educational Resources Information Center

Provides (1) background information showing how the sun, earth, air, and water work together to create weather; (2) six activities on this topic; and (3) a ready-to-copy coloring page on the water cycle. Each activity includes an objective, list of materials needed, recommended age level(s), subject area(s), and instructional strategies. (JN)

NatureScope, 1985

1985-01-01

383

Dress for the Weather  

ERIC Educational Resources Information Center

"If someone were traveling to our area for the first time during this time of year, what would you tell them to bring to wear? Why?" This question was used to engage students in a guided-inquiry unit about how climate differs from weather. In this lesson, students explored local and national data sets to give "travelers" advice when preparing for…

Glen, Nicole J.; Smetana, Lara K.

2010-01-01

384

Weather, Climate, and You.  

ERIC Educational Resources Information Center

|Information from the American Institute of Medical Climatologists on human responses to weather and climatic conditions, including clouds, winds, humidity, barometric pressure, heat, cold, and other variables that may exert a pervasive impact on health, behavior, disposition, and the level of efficiency with which individuals function is…

Blai, Boris, Jr.

385

Gulf of Maine: Weather  

NSDL National Science Digital Library

Lessons and activities from the Gulf of Maine Research Institute (formerly Gulf of Maine Aquarium), focused on hurricanes, El Nino, fog, and volcanic eruptions. Emphasis on important hurricanes of the past. Resources include lessons, guides for simple experiments, and a student weather network. Downloadable materials and additional webpages also provided.

386

Weather Specialist (AFSC 25120).  

ERIC Educational Resources Information Center

This correspondence course is designed for self-study to help military personnel to attain the rating of weather specialist. The course is organized in three volumes. The first volume, containing seven chapters, covers background knowledge, meteorology, and climatology. In the second volume, which also contains seven chapters, surface…

Air Univ., Gunter AFS, Ala. Extension Course Inst.

387

Palaeoclimate: Weathering away warmth  

NASA Astrophysics Data System (ADS)

At the end of the Eocene epoch, permanent ice cover developed over Antarctica as the Earth began to cool from greenhouse warmth. Sediment records off the Antarctic coast show spikes in weathering rate at the onset of ice growth that may indicate synchronous consumption of atmospheric carbon dioxide.

Haley, Brian A.

2013-02-01

388

Dress for the Weather  

NSDL National Science Digital Library

"If someone were traveling to our area for the first time during this time of year, what would you tell them to bring to wear? Why?" This question was used to engage students in a guided-inquiry unit about how climate differs from weather. In this lesson,

Smetana, Lara K.; Glen, Nicole J.

2010-04-01

389

Winds, Weather, and Deserts  

NSDL National Science Digital Library

This site contains 17 questions on the topic of wind and weathering, which covers the Coriolis Effect and wind characteristics. This is part of the Principles of Earth Science course at the University of South Dakota. Users submit an answer and are provided immediate verification.

Heaton, Timothy

390

Weather and Health  

NSDL National Science Digital Library

Funded by the National Environmental Education Foundation (NEEF), this course will help meteorologists and others broaden their understanding of the impacts of weather and climate on public health, including the impacts of heat waves and cold temperatures, winter storms and thunderstorms, flooding, drought, poor air quality, tornadoes, hurricanes, wildfire, ultraviolet radiation, and other phenomena.

2008-01-01

391

Blogging About the Weather  

NSDL National Science Digital Library

Since the majority of the content standards related to weather focus on forecasting, elementary students often spend a lot of time studying cloud types, fronts, storms, and using a barometer to read air pressure. Although this allows students to "do" scie

Evans, Kyle; Frazier, Wendy

2010-04-01

392

Weather and Agriculture  

NSDL National Science Digital Library

In this lesson plan students will research, discuss, and write reports on the relationship between climate and agriculture. They will pretend that they have just purchased farms in specific parts of the United States and will investigate the weather and climate of that region in order to maximize the chances that their farms will succeed.

393

Tactical Weather Expert System.  

National Technical Information Service (NTIS)

The objective of this project was to assess the feasibility of developing an expert system for tactical weather prediction. Using WILLARD, an expert system developed to predict severe thunderstorms in the Great Plains Regions of the United States, as a po...

H. B. Teates P. D. Lampru M. D. Condon

1987-01-01

394

Cold-Weather Sports  

MedlinePLUS

... Your Cool in the Cold and Snow Bad-Weather Driving Contact Us Print Additional resources Send to a friend Reprint guidelines Share this page using: What are these? Note: Clicking these links will take you to a site outside of KidsHealth's control.

395

External Resource: Rock Cycle Animation  

NSDL National Science Digital Library

This cutaway view of Earth shows where some common rock-forming processes occur. Embedded animations will illustrate the path of a rock moving through the rock cycle. Topics include: rock cycle, magma chamber, magma, igneous rock, sedimentary rock, erosio

1900-01-01

396

Towards Weather Ethics: From Chance to Choice with Weather Modification  

Microsoft Academic Search

The field of weather and climate ethics is a novel branch of applied ethics, based on environmental sciences and philosophy. Due to recent scientific findings concerning climate change, intentional weather and climate modification schemes have become even more relevant to finding feasible ways to moderate climate change and therefore are in need of careful analysis. When, if ever, can weather

Sanna Joronen; Markku Oksanen; Timo Vuorisalo

2011-01-01

397

Weather automation studies at the Otis Weather Test Facility  

Microsoft Academic Search

A description of the Otis Weather Test Facility (WTF) is presented, taking into account the distribution of surface-based and tower-mounted instrumentation at the WTF, the automation of the rotating beam ceilometer, the present weather decision tree, and slant visual range techniques. A demonstration model of a Modular Automated Weather System (MAWS) is also considered. The versatility of MAWS results from

D. A. Chisholm

1978-01-01

398

Spatial Variability of the Depth of Weathered and Engineering Bedrock using Multichannel Analysis of Surface Wave Method  

NASA Astrophysics Data System (ADS)

In this paper an attempt has been made to evaluate the spatial variability of the depth of weathered and engineering bedrock in Bangalore, south India using Multichannel Analysis of Surface Wave (MASW) survey. One-dimensional MASW survey has been carried out at 58 locations and shear-wave velocities are measured. Using velocity profiles, the depth of weathered rock and engineering rock surface levels has been determined. Based on the literature, shear-wave velocity of 330 ± 30 m/s for weathered rock or soft rock and 760 ± 60 m/s for engineering rock or hard rock has been considered. Depths corresponding to these velocity ranges are evaluated with respect to ground contour levels and top surface levels have been mapped with an interpolation technique using natural neighborhood. The depth of weathered rock varies from 1 m to about 21 m. In 58 testing locations, only 42 locations reached the depths which have a shear-wave velocity of more than 760 ± 60 m/s. The depth of engineering rock is evaluated from these data and it varies from 1 m to about 50 m. Further, these rock depths have been compared with a subsurface profile obtained from a two-dimensional (2-D) MASW survey at 20 locations and a few selected available bore logs from the deep geotechnical boreholes.

Anbazhagan, P.; Sitharam, T. G.

2009-03-01

399

Weathering and erosion fluxes of arsenic in watershed mass budgets.  

PubMed

Arsenic in natural waters and in soils represents a serious health hazard. Natural sources of this element in soil are the subject of this communication. Weathering mass balance of As and rates of weathering in soils are evaluated from monitored inputs and outputs in two small watersheds. These watersheds are located within the Celina-Mokrsko gold district, Czech Republic. Annual chemical weathering fluxes of As are calculated from the monthly weighted means of stream water and groundwater. The fluxes are corrected for atmospheric precipitation, agrochemical inputs, and biological uptake. Mechanical and chemical weathering rates of the arsenopyrite-bearing rocks in the watersheds were estimated from mass balance data on sodium and silica. The input of As due to total weathering of bedrock was estimated to be 1369 g ha(-1)yr(-1) in the Mokrsko watershed (MW) and 81 g ha(-1)yr(-1) in the Celina watershed (CW). These results indicate that the annual weathering rate of As in the watersheds represents more than 95% of the total As input to the soil. Accumulation rate of As in the soil was estimated at 311 g ha(-1)yr(-1) in MW and 69 g ha(-1)yr(-1) in CW. The mass balance method for calculation of weathering rate of As was used, and the results suggest that weathering could be the most important process in the As biogeochemistry of the areas with elevated As content in the bedrock. Simple model of weathering and erosion can be used successfully in estimating their role in As pollution on the scale of small watershed. The method is also useful for indicating the mass balance of As in soils that is controlled by both the natural and anthropogenic inputs and outputs of As. PMID:17067656

Drahota, Petr; Paces, Tomás; Pertold, Zdenek; Mihaljevic, Martin; Skrivan, Petr

2006-10-24

400

Microcracks in lunar rocks  

Microsoft Academic Search

Lunar samples contain abundant open microcracks that have closure characteristics completely unlike any shocked terrestrial rock; however, the microcracks present in the lunar rocks before the rocks reached the surface of the moon were likely similar to the microcracks in the shocked terrestrial rocks. Because the microcracks present in the lunar rocks in situ inside the moon were different, radically

G. Simmons

1979-01-01

401

Unusual Weather and Environmental Pollution.  

National Technical Information Service (NTIS)

The Japanese translation contains an attempt to report world weather trends, environmental pollution, and meteorological forecasting. It is a well-documented study ranging from analysis of man's earliest organized recording of the weather to fossil fuel p...

T. Asakura

1974-01-01

402

Cold Weather and Cardiovascular Disease  

MedlinePLUS

Cold Weather and Cardiovascular Disease Updated:Dec 11,2012 The fall and winter seasons will bring cooler temperatures, and ... and snow. It’s important to know how cold weather can affect your heart, especially if you have ...

403

Stay Safe in Cold Weather!  

MedlinePLUS

... Health and Aging » Publications Stay Safe in Cold Weather! What is hypothermia? Keep warm inside Bundle up ... to find more information Stay Safe in Cold Weather! Learn Why You Need to Stay Warm When ...

404

All-Weather Home Building.  

National Technical Information Service (NTIS)

To determine the experiences of contractors in building in a variety of weather conditions, the following tasks are reported and discussed: (1) a summary of literature review and annotated bibliography for all - weather home building, (2) a questionnaire ...

1975-01-01

405

Space Weather: A Research Perspective  

NSDL National Science Digital Library

The National Research Council (NRC) sponsors the Space Weather: A Research Perspective Website. Space weather occurs due to the behavior of the sun, the "nature of Earth's magnetic field and atmosphere, and our location in the solar system." Space weather research will be useful for space weather forecasting, satellite troubleshooting, and gaining a greater understanding of Earth's place in space. To further understand space weather, the user can browse through sections such as What is Space Weather, The Elements of Near-Earth Space, Practical Consequences of Space Weather, and Earth-Space Meteorology, among others. Each section provides images, diagrams, and descriptions. Weather links and resources, as well as a glossary, round out the site.

406

External Resource: Erosion and Weathering  

NSDL National Science Digital Library

This is a Teachers' Domain photo essay with images that depict surface features on Earth that result from weathering and erosion, as well as measures designed to mitigate their unwanted effects. Topics: weathering, erosion, sediments, dunes, deltas, glaci

1900-01-01

407

Rare earth element sorption by basaltic rock: Experimental data and modeling results using the “Generalised Composite approach”  

Microsoft Academic Search

Sorption of the 14 rare earth elements (REE) by basaltic rock is investigated as a function of pH, ionic strength and aqueous REE concentrations. The rock sample, originating from a terrestrial basalt flow (Rio Grande do Sul State, Brazil), is composed of plagioclase, pyroxene and cryptocrystalline phases. Small amounts of clay minerals are present, due to rock weathering. Batch sorption

E. Tertre; A. Hofmann; G. Berger

2008-01-01

408

Make Your Own Weather Station  

NSDL National Science Digital Library

This three-part activity shows learners how to build three meteorology tools: a wind vane, a rain gauge, and a barometer. Then, they can use their tools to build their own weather station to record data about the weather, study the data to detect patterns, and use the patterns to predict the weather. This lesson also includes information about the difference between weather and climate.

History, American M.

2012-06-26

409

Weather Variation and Crop Yields  

Microsoft Academic Search

While the efiects of rising mean temperatures on agricultural output have been studied extensively, there is limited discussion of the impact of inter-annual weather variation on crop yields. This paper estimates the link between weather and crop yields separating the in?uence of (i) mean weather outcomes (i.e., climate) to which a farmer can adapt from (ii) unpredictable year-to-year weather ?uctuations

Wolfram Schlenker

410

Chemical weathering, river geochemistry and atmospheric carbon fluxes from volcanic and ultramafic regions on Luzon Island, the Philippines  

Microsoft Academic Search

We investigated rates of chemical weathering of volcanic and ophiolitic rocks on Luzon Island, the Philippines. Luzon has a tropical climate and is volcanically and tectonically very active, all factors that should enhance chemical weathering. Seventy-five rivers and streams (10 draining ophiolites, 65 draining volcanic bedrock) and two volcanic hot springs were sampled and analyzed for major elements, alkalinity and

H. H. Schopka; L. A. Derry; C. A. Arcilla

2011-01-01

411

Fossil organic carbon fluxes released by chemical and mechanical weathering. Jurassic marls of Draix experimental watersheds, France  

Microsoft Academic Search

Fate of Fossil Organic Carbon (FOC), originating from sedimentary rock weathering, is a major unknown into carbon cycle. Generally considered as degradable and as a CO2 source for the atmosphere, its occurrence was highlighted by numerous studies in various pools, such as rivers, soils and recent sediments, indicating a potential resistance to weathering. This work focuses on annual FOC fluxes

Y. Graz; C. di-Giovanni; Y. Copard; M. Boussafir; F. Laggoun-Défarge; N. Mathys; F. Rey; S. Sizaret

2009-01-01

412

Science Sampler: Clever with weather  

NSDL National Science Digital Library

In eighth-grade Earth science at Louisville Middle School in Louisville, Colorado, students learn how large-scale weather patterns such as the jet stream and weather fronts interact to generate local weather conditions. The authors have developed a modeli

Crowder, David; Hoenigman, Rhonda

2011-02-01

413

Weather Fundamentals: Climate & Seasons. [Videotape].  

ERIC Educational Resources Information Center

|The videos in this educational series for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes), describes weather patterns and cycles around the globe. The various types of climates around…

1998

414

Weather Specialist/Aerographer's Mate.  

ERIC Educational Resources Information Center

|This course trains Air Force personnel to perform duties prescribed for weather specialists and aerographer's mates. Training includes meteorology, surface and ship observation, weather radar, operation of standard weather instruments and communications equipment, and decoding and plotting of surface and upper air codes upon standard maps and…

Chanute AFB Technical Training Center, IL.

415

Weather Fundamentals: Climate & Seasons. [Videotape].  

ERIC Educational Resources Information Center

The videos in this educational series for grades 4-7, help students understand the science behind weather phenomena through dramatic live-action footage, vivid animated graphics, detailed weather maps, and hands-on experiments. This episode (23 minutes), describes weather patterns and cycles around the globe. The various types of climates around…

1998

416

Influence of weather on osteoarthritics  

Microsoft Academic Search

This exploratory study examined the effects of selected weather variables on pain and pain-related stress in osteoarthritic subjects. Urban and rural dwelling arthritics who perceived that weather made their symptoms worse and those who did not were surveyed. Some persons with osteoarthritis in urban Chicago were more weather sensitive than their rural counterparts in Grand Forks, North Dakota. Multiple regression

Joyce M. Laborde; William A. Dando; Marjorie J. Powers

1986-01-01

417

Differences Between Climate and Weather  

NSDL National Science Digital Library

In this activity, students collect weather data over several days or weeks, graph temperature data, and compare the temperature data collected with long-term climate averages from where they live. Understanding the difference between weather and climate and interpreting local weather data are important first steps to understanding larger-scale global climate changes.

Research, National C.

418

Global CO 2-consumption by chemical weathering: What is the contribution of highly active weathering regions?  

NASA Astrophysics Data System (ADS)

CO 2-consumption by chemical weathering of silicates and resulting silicate/carbonate weathering ratios influences long-term climate changes. However, little is known of the spatial extension of highly active weathering regions and their proportion of global CO 2-consumption. As those regions may be of significant importance for global climate change, global CO 2-consumption is calculated here at high resolution, to adequately represent them. In previous studies global CO 2-consumption is estimated using two different approaches: i) a reverse approach based on hydrochemical fluxes from large rivers and ii) a forward approach applying spatially explicit a function for CO 2-consumption. The first approach results in an estimate without providing a spatial resolution for highly active regions and the second approach applied six lithological classes while including three sediment classes (shale, sandstone and carbonate rock) based at a 1° or 2° grid resolution. It remained uncertain, if the applied lithological classification schemes represent adequately CO 2-consumption from sediments on a global scale. This is due to the large variability of sediment properties, their diagenetic history and the contribution from carbonates apparent in silicate dominated lithological classes. To address these issues, a CO 2-consumption model, trained at high-resolution data, is applied here to a global vector based lithological map with 15 lithological classes. The calibration data were obtained from areas representing a wide range of weathering rates. Resulting global CO 2-consumption by chemical weathering is similar to earlier estimates (237 Mt C a - 1 ) but the proportion of silicate weathering is 63%, and thus larger than previous estimates (49 to 60%). The application of the enhanced lithological classification scheme reveals that it is important to distinguish among the various types of sedimentary rocks and their diagenetic history to evaluate the spatial distribution of rock weathering. Results highlight the role of hotspots (> 10 times global average weathering rates) and hyperactive areas (5 to 10 times global average rates). Only 9% of the global exorheic area is responsible for about 50% of CO 2-consumption by chemical weathering (or if hotspots and hyperactive areas are considered: 3.4% of exorheic surface area corresponds to 28% of global CO 2-consumption). The contribution of endorheic areas to the global CO 2-consumption is with 3.7 Mt C a - 1 only minor. A significant impact on the global CO 2-consumption rate can be expected if identified highly active areas are affected by changes in the overall spatial patterns of the hydrological cycle due to ongoing global climate change. Specifically if comparing the Last Glacial Maximum with present conditions it is probable that also the global carbon cycle has been affected by those changes. It is expected that results will contribute to improve global carbon and global circulation models.

Hartmann, Jens; Jansen, Nils; Dürr, Hans H.; Kempe, Stephan; Köhler, Peter

2009-12-01

419

Long-term rates of chemical weathering and physical erosion from cosmogenic nuclides and geochemical mass balance  

Microsoft Academic Search

Quantifying long-term rates of chemical weathering and physical erosion is important for understanding the long-term evolution of soils, landscapes, and Earth's climate. Here we describe how long-term chemical weathering rates can be measured for actively eroding landscapes using cosmogenic nuclides together with a geochemical mass balance of weathered soil and parent rock. We tested this approach in the Rio Icacos

Clifford S. Riebe; James W. Kirchner; Robert C. Finkel

2003-01-01

420

Chemical weathering in Malay Peninsula and North Borneo: Clay mineralogy and element geochemistry of river surface sediments  

Microsoft Academic Search

Weathering products of silicate rocks are particularly useful for evaluating the continental chemical weathering on the Earth’s\\u000a surface and its mechanism. Clay mineralogy and major-element geochemistry of surface sediment samples collected in major rivers\\u000a of Malay Peninsula and North Borneo in the tropical Southeast Asian region are used to study the present chemical weathering\\u000a process and its controlling factors of

Hao Wang; ZhiFei Liu; Edlic Sathiamurthy; Christophe Colin; JianRu Li; YuLong Zhao

2011-01-01

421

Lithology and Geochemistry of the Weathering Crust.  

National Technical Information Service (NTIS)

Contents: Development of the weathering crust theory; Factors influencing weathering crust formation; Weathering. geochemical types and stages; Geochemical thermodynamics of the weathering and migration of elements; Effect of the mineral composition of ro...

K. I. Lukashev

1970-01-01

422

Whether weather affects music  

NASA Astrophysics Data System (ADS)

The creative output of composers, writers, and artists is often influenced by their surroundings. To give a literary example, it has been claimed recently that some of the characters in Oliver Twist and A Christmas Carol were based on real-life people who lived near Charles Dickens in London [Richardson, 2012]. Of course, an important part of what we see and hear is not only the people with whom we interact but also our geophysical surroundings. Of all the geophysical phenomena to influence us, the weather is arguably the most significant because we are exposed to it directly and daily. The weather was a great source of inspiration for artists Claude Monet, John Constable, and William Turner, who are known for their scientifically accurate paintings of the skies [e.g., Baker and Thornes, 2006].

Aplin, Karen L.; Williams, Paul D.

2012-09-01

423

Seasonal Extreme Weather Forecasts  

NSDL National Science Digital Library

Forecasts for UK winter gales and severe gales, North Atlantic and US landfalling hurricanes, Northwest Pacific and Far East landfalling typhoons, Southwest Pacific and Australian landfalling cyclones, and US Cooling Degree Days are available at this site from the Benfield Greig Hazard Research Centre at University College, London. Forecast summaries, descriptions of forecasting methodology, and graphics of historical and predicted events through time are presented in .pdf format for each weather subcategory. This site also tells users when the next predictions are to be released and has links to press releases and other extreme weather Websites. This is a good site for those interested in methods of climatology or those who want to prepare for that next big typhoon.

424

Weather Crossword Puzzle  

NSDL National Science Digital Library

This section of the Windows to the Universe web site features weather crossword puzzles. Topics include the Earth's atmosphere, temperature, precipitation, fronts, clouds, winds, hurricanes, tornadoes, thunderstorms, weather, lightning and thunder, how hurricanes form, and snow. Links at the bottom of the page allow users to reference other Windows to the Universe sites to help solve the puzzles. Windows to the Universe is a user-friendly learning system pertaining to the Earth and Space sciences. The objective of this project is to develop an innovative and engaging web site that spans the Earth and Space sciences and includes a rich array of documents, including images, movies, animations, and data sets that explore the Earth and Space sciences and the historical and cultural ties between science, exploration and the human experience. Links at the top of each page allow users to navigate between beginner, intermediate and advanced levels.

Johnson, Roberta

2000-07-01

425

1980 Weather summary  

NASA Astrophysics Data System (ADS)

The weather in the United States during 1980 was bad. A 3-month heat wave in the southwest caused about $20 billion in ruined crops, an increase in power consumption, and damage to roads and highways. Nationwide, the heat killed 1320 people. Floods caused more than $1 billion in losses. Hurricane Allen caused about $500 million in property losses and took two lives.The highest temperature reading during 1980, 51°C (124°F), was reached five times. Locations were at Bull Head, Arizona; Death Valley, California; and three times at Baker, California. Preliminary figures also show that the lowest temperature for the year was recorded at Tok weather station, 150 miles southeast of Fairbanks, Alaska. There the mercury plummeted to -56°C (-68°F). In the lower 48 states the minimum thermometer reading was -44°C at Wisdom, Montana.

Bell, Peter M.

426

Weather Variables Lab  

NSDL National Science Digital Library

This activity has students collect weather data for eight days and enter it into a chart to look for relationships. Students should find the relationship between air temperature, dew point, relative humidity, and the chance of precipitation. They also should see the relationship between air pressure and cloud cover and the relationship between temperature and air pressure. The site also provides a list of required materials, a formatted copy of the data table, and links to online references.

Hildreth, Carol

427

Terminal Doppler weather radar  

Microsoft Academic Search

The terminal Doppler weather radar (TDWR) system, now under development, will provide automatic detection of microbursts and low-level wind shear. This paper discusses the TDWR performance parameters and describes its structural elements, including the antenna subsystem, the transmitter, the receiver\\/exciter, the digital signal processor, and the radar product generator\\/remote monitoring subsystem. Attention is also given to the processes of the

M. Michelson; W. W. Shrader; J. G. Wieler

1990-01-01

428

Astrobiological Implications of Rock Varnish in Tibet  

NASA Astrophysics Data System (ADS)

The study of terrestrial geomicrobiology and its relationship to rock weathering processes is an essential tool in developing analogues for similar processes that may have occurred on Mars. Most studies of manganese-enhanced rock varnish have focused on samples taken from warm arid desert regions. Here, we examine samples obtained from eolian-abraded lava flows of the 4700-4800 m high Ashikule Basin in Tibet. Because it receives approximately 300 mm of precipitation annually, this site is nowhere near as dry as Atacama Desert locales. However, the dusty, sulfate-rich, high-altitude and high-UV flux environment of the Tibetan locale offers new insight into rock varnish formation processes in a terrestrial environment that displays some attributes similar to those expected on early Mars. Microprobe measurements reveal that Mn enhancements in varnish are two orders of magnitude above the dust source, but Fe is only enhanced by a factor of three. Manganese-enhancing bacterial forms are not abundant but are still approximately 3 times more common than in Mojave and Sonoran Desert varnishes. In addition to its occurrence in subaerial positions, Tibetan varnish also occurs in micron-scale "pods" enveloped by silica glaze and as remobilized constituents that have migrated into the underlying weathering rind. A lack of surficial Mn-rich varnish, therefore, might not imply the absence of varnish. In contrast to suggestions that silica glaze might be a good source of microbial fossils and a key to varnish formation, we did not observe any clear microfossil forms entombed in silica glaze; further, there is no gradation between varnish and silica glaze but only distinct contacts. %K Analogue, Astrobiology, Bacteria, Biomineralization, Desert varnish, Geomicrobiology, Life on Mars, Manganese enhancement, Rock coating, Rock varnish, Microstromatolite, Tibet, Weathering

Krinsley, David; Dorn, Ronald I.; DiGregorio, Barry

2009-08-01

429

A Photographic Atlas of Rock Breakdown Features in Geomorphic Environments  

NSDL National Science Digital Library

This downloadable (15 mb) atlas features photos of rocks, rock formations, and landscapes that have been shaped by aeolian (wind), fluvial (river), and other weathering processes. The photos are accompanied by descriptions of the features and discussion of the processes involved in creating them. There is also a discussion of the applicability of these same processes to explain similar features seen on Mars and Venus, and the use of high-resolution imagery from Mars to identify these features. A bibliography is included.

430

Pipelines and Space Weather  

NASA Astrophysics Data System (ADS)

Long conductors of all types on Earth's surface are subject to disturbance and disruption by telluric currents (currents that flow within the Earth or on its surface) induced by space weather events. Attention is most often paid to the effects that these currents can produce in electric grids. After all, if an electric power system is disrupted, many other modern infrastructures that depend on the secure and continuous supply of electrical power will also be affected. A recent technical paper in Space Weather by R. A. Marshall and colleagues draws needed attention to the effects of telluric currents on long pipelines. This is a space weather topic that often does not receive the attention it warrants in terms of its critical relevance to modern-day life. Pipelines have long used cathodic protection systems to mitigate the corrosion of the pipes that can arise from potential differences between the ground and the pipes. These potential differences occur because telluric currents flow more readily in the pipes than in the ground. While pipeline engineers have long worked hard on this problem, it was the design and installation in the mid-1970s of the Alaska pipeline directly under the auroral zone that drew enhanced attention to this topic.

Lanzerotti, Louis J.

2010-05-01

431

Weather service upgrade too costly?  

NASA Astrophysics Data System (ADS)

America needs timely and accurate weather forecasting, said Ernest F. Hollings (D-S.C.), chairman of the Senate Committee on Commerce, Science, and Transportation on National Ocean Policy. Calling the existing warning and forecast system dangerously obsolete, Hollings said that new technology “should dramatically improve the accuracy and timeliness of weather predictions,” as we face the new challenge of bringing the National Weather Service into the 21st century. Hollings' committee heard testimony to consider the modernization of the NWS and pending legislation (S98, S916) on June 18.Major components of the Weather Service Modernization program, according to John A. Knauss, administrator of the National Oceanic and Atmospheric Administration, are the Next Generation Weather Radar (NEXRAD), a new generation of Geostationary Operational Environmental Satellites (GOES-NEXT), the Automated Surface Observing System (ASOS), and the Advanced Weather Interactive Processing System (AWIA). The best defense against severe weather—early warnings—is probably hampered by outdated equipment, he added.

Bush, Susan

432

Engineering classification and index properties of a weathered granite  

Microsoft Academic Search

Summary  A comprehensive range of classification, or index, and engineering design tests have been carried out on the seven stages\\u000a of weathering of rock material recognised in the Hingston Down granite from east Cornwall, England. Interrelationships have\\u000a been determined for all test results. It is concluded that the quick absorption, Schmidt hammer and point load strength tests\\u000a are reliable and simple

T. Y. Irfan; W. R. Dearman

1978-01-01

433

Mycorrhizal weathering: A true case of mineral plant nutrition?  

Microsoft Academic Search

Weatherable minerals in all podzol surface soils andshallow granitic rock under European coniferousforests studied hitherto are criss-crossed bynumerous open, tubular pores, 3–10 µm in width. Wehypothesize that these pores were formed bycomplex-forming, low-molecular weight organic acidsexuded by or formed in association with mycorrhizalfungi. It is well known that ectomycorrhizal myceliumrepresents a greatly extended, and better distributed,surface area for the absorption

Nico van Breemen; Roger Finlay; Ulla Lundström; Antoine G. Jongmans; Reiner Giesler; Mats Olsson

2000-01-01

434

Physical weathering of marbles caused by anisotropic thermal expansion  

Microsoft Academic Search

Marbles as building stones as well as in their natural environments show complex weathering phenomena. The most important\\u000a damage scenario is based on the highly anisotropic thermal expansion coefficient ? of calcite, i.e. extreme expansion parallel and contraction normal to the crystallographic c-axis. Therefore, the rock fabric\\u000a and especially the lattice-preferred orientation (texture) of calcite and\\/or dolomite as the predominant

S. Siegesmund; K. Ullemeyer; T. Weiss; E. K. Tschegg

2000-01-01

435

Characterization of Fungal Community Structure on a Weathered Pegmatitic Granite  

Microsoft Academic Search

This study exploited the contrasting major element chemistry of adjacent, physically separable crystals of framework and sheet\\u000a silicates in a pegmatitic granite to investigate the mineralogical influences of fungal community structure on mineral surfaces.\\u000a Large intact crystals of variably weathered muscovite, plagioclase, K-feldspar, and quartz were individually extracted, together\\u000a with whole-rock granite. Environmental scanning electron microscopy (ESEM) revealed a diversity

Deirdre B. Gleeson; Nicholas Clipson; Karrie Melville; Geoffrey M. Gadd; Frank P. McDermott

2005-01-01

436

Chemical Composition of Martian Rocks  

NASA Astrophysics Data System (ADS)

In situ analyses of martian surface rocks (and soils) provided data about the chemical composition of several landing sites. One of the used techniques is the alpha-induced x-ray emission applied by the Alpha Particle X-Ray Spectrometer (APXS) onboard the current Mars Exploration Rovers (MER) Spirit and Opportunity and onboard the preceding Mars Pathfinder Rover Sojourner (MPF Mission). These measurements encompass the determination of major, minor, and (for the MER APXS) trace elements, such as Ni, Zn, and Br, as well as Cu, Pb, Sr, Y, Ga, and Ge. The obtained data indicate a remarkable compositional difference between the rocks at the different landing sites, whereas most soils including those measured by the Viking landers are chemically similar. Initially, the only chemical data of Mars were obtained by the study of a class of meteorites that turned out to be martian, which was furthermore confirmed by the discovery of a rock (by rover Opportunity) that is chemically related to those meteorites. The rocks at the Pathfinder landing site turned out to be richer in Si and K than the martian meteorites and all rocks encountered at the MER sites. At Gusev crater (the first MER landing site), two geological regions were encountered along the rover Spirit's traverse: the plains and the hills. Rocks in the plains resemble primitive basalts, while rocks located in the Columbia Hills revealed different types. Several rock classes could be cataloged based on their chemical composition. Most of the hills rocks are significantly weathered and enriched in mobile elements, such as P, Zn, S, Cl, and Br. On the other hand, a suite of ultramafic rocks was discovered for the first time on Mars. The rocks at Meridiani Planum (the second MER landing site) are salt-rich siliciclastic sediments. All rocks showed much higher S contents than the soils. High concentrations of Cl and Br were also discovered at various samples. Huge quantities of spherules were found on top of soils and outcrops along the rover's traverse. APXS measurements revealed that these spherules contain high amounts of iron that is mainly present as the mineral hematite (determined by Mössbauer spectrometry). The formation of hematite is typically, but not exclusively, an indicator for aqueous activities under oxidizing conditions. The in situ measurements at both MER landing sites point to a variety of sedimentary processes and various types of alteration processes; hence, they show clear evidence of ancient aqueous environments that discontinued long time, ago. The combination of in situ measurements and element correlations obtained by the martian meteorites implies an ancient basaltic crust with high abundances of incompatible elements (K, Rb, Nd, U, and Th) and volatile elements (S, Cl). Compared to the Earth's mantle, the martian mantle contains about twice as much Fe, is richer in moderately volatile elements like K, and has a much higher abundance of phosphorus. In conjunction with chemical data obtained from orbit, such as gamma-ray spectrometry carried out by the Mars Odyssey spacecraft, a global estimation of the composition of the martian surface is obtained and, furthermore, crustal composition can be derived.

Brueckner, J.

2007-05-01

437

Antarctic weathering and carbonate compensation at the Eocene-Oligocene transition  

NASA Astrophysics Data System (ADS)

During the Eocene-Oligocene transition about 34 million years ago, permanent ice cover developed on Antarctica. This pronounced climate transition was accompanied by the deepening of the carbonate compensation depth in the oceans and perturbations in atmospheric carbon dioxide concentrations. These changes may have been linked to continental weathering on Antarctica, but reconstructing which rock types were subject to weathering and the intensity of that weathering has proved challenging. Here we compare the lead (Pb) isotope values of seawater as recorded by extractions from decarbonated bulk sediments and those of silicate detrital fractions from deep-sea sediments from sites in the Southern Ocean that span the Eocene-Oligocene transition. These comparisons allowed us to assess local weathering inputs of Pb from Antarctica. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios suggest high rates of chemical weathering in the late Eocene, which would have helped draw down atmospheric CO2 to levels necessary for glacial initiation. Mechanical weathering and the introduction of newly exposed material was enhanced during the establishment of the Antarctic ice sheet. We also observe a divergence of seawater 206Pb/204Pb from detrital values during the Eocene-Oligocene transition, which implies an additional source of weathered material. We argue that the weathering of carbonate basement rock from Antarctica could explain the 206Pb/204Pb trend, and could have contributed to the observed deepening of the carbonate compensation depth through contributions to ocean alkalinity.

Basak, Chandranath; Martin, Ellen E.

2013-02-01

438

Martian weathering processes: Terrestrial analog and theoretical modeling studies  

NASA Astrophysics Data System (ADS)

Understanding the role of water in the Martian near-surface, and its implications for possible habitable environments, is among the highest priorities of NASA's Mars Exploration Program. Characterization of alteration signatures in surface materials provides the best opportunity to assess the role of water on Mars. This dissertation investigates Martian alteration processes through analyses of Antarctic analogs and numerical modeling of mineral-fluid interactions. Analog work involved studying an Antarctic diabase, and associated soils, as Mars analogs to understand weathering processes in cold, dry environments. The soils are dominated by primary basaltic minerals, but also contain phyllosilicates, salts, iron oxides/oxyhydroxides, and zeolites. Soil clay minerals and zeolites, formed primarily during deuteric or hydrothermal alteration of the parent rock, were subsequently transferred to the soil by physical rock weathering. Authigenic soil iron oxides/oxyhydroxides and small amounts of poorly-ordered secondary silicates indicate some contributions from low-temperature aqueous weathering. Soil sulfates, which exhibit a sulfate- aerosol-derived mass-independent oxygen isotope signature, suggest contributions from acid aerosol-rock interactions. The complex alteration history of the Antarctic materials resulted in several similarities to Martian materials. The processes that affected the analogs, including deuteric/ hydrothermal clay formation, may be important in producing Martian surface materials. Theoretical modeling focused on investigating the alteration of Martian rocks under acidic conditions and using modeling results to interpret Martian observations. Kinetic modeling of the dissolution of plagioclase-pyroxene mineral mixtures under acidic conditions suggested that surfaces with high plagioclase/pyroxene, such as several northern regions, could have experienced some preferential dissolution of pyroxenes at a pH less than approximately 3-4. Modeling of the equilibrium secondary mineralogy produced by acidic, low- temperature weathering of potential Martian protoliths has been used to evaluate possible Martian mineral formation conditions. This modeling showed that silica-rich deposits, such as those in Gusev Crater, Mars, could form under low-temperature, low-pH (less than approximately 2) and high water/rock ratio conditions. High water/rock conditions could represent acid flow through rocks, discharge from an acid spring, and/or surface flows.

McAdam, Amy Catherine

2008-06-01

439

Linkages Between Physical Erosion and Chemical Weathering, Measured by Cosmogenic Nuclides and Geochemical Mass Balance  

Microsoft Academic Search

We have recently shown how rates of physical erosion and chemical weathering can be measured over 1,000- to 10,000-year time scales, using cosmogenic 10Be measurements coupled with the bulk elemental composition of regolith and its parent rock. We have used these methods to measure long-term rates of physical erosion and chemical weathering for 42 sites, encompassing widely varying climates and

C. S. Riebe; J. W. Kirchner; R. C. Finkel

2004-01-01

440

An aem-tem study of weathering and diagenesis, Abert Lake, Oregon: I. Weathering reactions in the volcanics  

USGS Publications Warehouse

Abert Lake in south-central Oregon provides a site suitable for the study of sequential weathering and diagenetic events. In this first of two papers, transmission electron microscopy was used to characterize the igneous mineralogy, subsolidus alteration assemblage, and the structural and chemical aspects of silicate weathering reactions that occur in the volcanic rocks (basalts, basaltic andesites, and dacitic/ rhyolitic extrusive and pyroclastics) that outcrop around the lake. Olivine and pyroxene replacement occurred topotactically, whereas feldspar and glass alteration produced randomly oriented smectite in channels and cavities. The tetrahedral, octahedral, and interlayer compositions of the weathering products, largely dioctahedral smectites, varied with primary mineral composition, rock type, and as the result of addition of elements released from adjacent reaction sites. Weathering of the highly evolved, Fe-rich Jug Mountain complex at the north end of the lake produced a homogeneous smectite assemblage that contrasts with the heterogeneous smectite assemblage replacing the volcanics along the eastern margin of the lake. The variability within and between the smectite assemblages highlights the microenvironmental diversity, fluctuating redox conditions, and variable solution chemistry associated with mineral weathering reactions in the surficial environment. Late-stage exhalative and aqueous alteration of the volcanics redistributed many components and formed a variety of alkali and alkali-earth carbonate, chloride, sulfate, and fluoride minerals in vugs and cracks. Overall, substantial Mg, Si, Na, Ca, and K are released by weathering reactions that include the almost complete destruction of the Mg-smectite that initially replaced olivine. The leaching of these elements from the volcanics provides an important source of these constituents in the lake water. The nature of subsequent diagenetic reactions resulting from the interaction between the materials transported to the lake and the solution will be described in part II (Banfield et al., 1991). ?? 1991.

Banfield, J. F.; Jones, B. F.; Veblen, D. R.

1991-01-01

441

Brazilian Space Weather Program  

NASA Astrophysics Data System (ADS)

A space weather program is being initiated at the Brazilian National Institute for Space Research (INPE) to study events from their initiation on the sun to their impacts on the earth, including their effects on space-based and ground-based technological systems. The program is built on existing capabilities at INPE, which include scientists with a long tradition and excellence in the observation, analysis and modeling of solar and solar-terrestrial phenomena and an array of geophysical instruments that spans all over the Brazilian territory from the north to south of the magnetic dip equator. Available sensors include solar radio frequency receivers and telescopes, optical instruments and solar imagers, GNSS receivers, ionosondes, radars, allsky imagers, magnetometers and cosmic ray detectors. In the equatorial region, ionosphere and thermosphere constitute a coupled system with electrodynamical and plasma physical processes being responsible for a variety of peculiar phenomena. The most important of them are the equatorial electrojet current system and its instabilities, the equatorial ionization anomaly, and the plasma instabilities/irregularities of the night-time ionosphere (associated with the plasma bubble events). In addition, space weather events modify the equatorial ionosphere in a complex and up to now unpredictable manner. Consequently, a main focus of the program will be on monitoring the low, middle and upper atmosphere phenomena and developing a predictive model of the equatorial ionosphere through data assimilation, that could help to mitigate against the deleterious effects on radio communications and navigation systems. The technological, economic and social importance of such activities was recognized by the Brazilian government and a proposal for funding was approved for the period 2008-2011. New ground instruments will be installed during this period allowing us to extend our current capability to provide space weather observations, accurate forecasts of space weather conditions, and timely hazard alert warnings. The program is expected to be fully operational for the peak activity of the next solar maximum, but for its future growth and development it is essential to have a wide network of international collaborations.

Padilha, Antonio; Takahashi, Hisao; de Paula, Eurico; Sawant, Hanumant; de Campos Velho, Haroldo; Vitorello, Icaro; Costa, Joaquim; Souza, Jonas; Cecatto, José; Mendes, Odim; Gonzalez Alarcon, Walter Demétrio

442

Terminal Doppler weather radar  

NASA Astrophysics Data System (ADS)

The terminal Doppler weather radar (TDWR) system, now under development, will provide automatic detection of microbursts and low-level wind shear. This paper discusses the TDWR performance parameters and describes its structural elements, including the antenna subsystem, the transmitter, the receiver/exciter, the digital signal processor, and the radar product generator/remote monitoring subsystem. Attention is also given to the processes of the base data formation, point target removal, signal-to-noise thresholding, and velocity de-aliasing and to the TDWR algorithms and displays. A schematic diagram of the TDWR system is presented.

Michelson, M.; Shrader, W. W.; Wieler, J. G.

1990-02-01

443

Global Weather Patterns  

NSDL National Science Digital Library

This tutorial introduces students to global weather patterns and how they affect the kinds of trees and plants that grow in different latitudes of the Earth. The discussion covers the tropics and the lush rainforests that live there, temperate forests in the mid-latitudes, and boreal forests in the far north. There is also a description of how treeless areas occur in various climate zones (desert, tundra, savannah), and how plants adapt to low-water conditions in the desert. A quiz and glossary are included.

444

Become A Rock Expert!  

NSDL National Science Digital Library

Rocks are the most common material on earth. But how do we identify and classify rocks? Your mission is to become an amateur geologist by exploring the different types of rocks; sorting them by color, hardness, texture, layering, and particle size; and discussing with your classmates what you learned! Rockin Rocks, Ms. Andersen's site about the Big6. Rock Expert Webquest INTRODUCTION The Museum of Natural History is creating a new exhibit on rocks and minerals. They are looking for expert knowledge to share with museum visitors. They need your help, Rock Expert! MISSION You will work as an Amateur Geologist for the Museum of Natural ...

Andersen, Ms.

2010-11-13

445

Groundwater Exploration in Hard Rock Areas of Vizianagaram District, Andhra Pradesh, India  

Microsoft Academic Search

Identifying a good site for groundwater exploration in hard rock terrain is a challenging task. In hard rocks, groundwater occurs in secondary porosity developed due to weathering, fracturing, faulting, etc., which is highly variable and varies sharply within very short distances, contributing to near-surface inhomogeneity. In such situations topographic, hydrogeological and geomorphological features provide useful clues for the selection of

S. N. Das; N. C. Mondal; V. S. Singh

446

Dilatometrical behaviour of porous calcareous rock samples subjected to freeze-thaw cycles  

Microsoft Academic Search

Dilatometry can be used in geomorphology as an evaluation method for the behaviour of rocks during weathering by frost shattering and also for the role of unfrozen water migration during this process. It has already been demonstrated in other publications that calcareous rock cylinders undergoing humidification\\/drying cycles (no freezing) vary in length. These length changes are most significant when water

A. Prick

1995-01-01

447

Characterizing the geomorphic setting of precariously balanced rocks using terrestrial laser scanning technology  

Microsoft Academic Search

Terrestrial laser scanning (TLS) technology is rapidly becoming an effective three-dimensional imaging tool. Precariously balanced rocks are a subset of spheroidally weathered boulders. They are balanced on bedrock pedestals and are formed in upland drainage basins and pediments of exhumed plutons. Precarious rocks are used as negative evidence of earthquake-driven extreme ground motions. Field surveys of PBRs are coupled with

D. E. Haddad; R. Arrowsmith

2009-01-01

448

Sedimentary rocks at Meridiani Planum: Origin, diagenesis, and implications for life on Mars  

Microsoft Academic Search

The MER rover Opportunity has carried out the first outcrop-scale investigation of ancient sedimentary rocks on Mars. The rocks, exposed in craters and along fissures in Meridiani Planum, are sandstones formed via the erosion and re-deposition of fine grained siliciclastics and evaporites derived from the chemical weathering of olivine basalts by acidic waters. A stratigraphic section more than seven meters

Steven W. Squyres; Andrew H. Knoll

2005-01-01

449

Rock fragment distributions and regolith evolution in the Ouachita Mountains, Arkansas, USA  

Microsoft Academic Search

Rock fragments in the regolith are a persistent property that reflects the combined influences of geologic controls, erosion, deposition, bioturbation, and weathering. The distribution of rock fragments in regoliths of the Ouachita Mountains, Arkansas, shows that sandstone fragments are common in all layers, even if sandstone is absent in parent material. Shale and sandstone fragments are produced at the bedrock

Jonathan D. Phillips; Ken Luckow; Daniel A. Marion; Kristin R. Adams

2005-01-01

450

Recent Near-Neutral Chemical Weathering of Martian High-Latitude Surfaces  

NASA Astrophysics Data System (ADS)

Recent scientific investigations of Mars, including those conducted by TES, OMEGA, and the MER lander missions, have expanded the discussion about aqueous alteration on Mars. Results from these missions indicate that the styles and/or intensity of water-rock interactions on Mars have changed over time, and they provide evidence for geographical differences in weathering typically associated with latitude. Work that we have done on the spectroscopy of terrestrial weathering rinds and rock coatings indicates that small volumes of weathering products mixed with primary minerals considerably change thermal emission spectra of volcanic rocks. Based on that work, we suggest that low-intensity chemical weathering leading to the formation of small volumes of weathering products can explain the global distribution of TES observations. Whereas MER results indicate acidic alteration at low latitudes since the late Noachian, we suggest that major surface- mineralogical differences observed by TES (and broadly corroborated by OMEGA) may be due to near-neutral pH chemical weathering, pedogenically driven by near-surface pore waters at mid-to-high latitudes.

Kraft, M. D.; Michalski, J. R.; Sharp, T. G.; Rampe, E. B.

2006-12-01

451

Dan's Wild Wild Weather Page  

NSDL National Science Digital Library

Created by a meteorologist, this weather site is for students from 6 to 16 years old and their parents. Information and experiments are provided about radar, tornadoes, clouds, precipitation, lightning, humidity, satellites, temperature, forecasting, hurricanes, wind, and climate. While in the tornado section, students can click on any state on the map to get a hourly weather report, state forecast, zone forecast, short term forecast, forecast discussion, weather summary, public information, climate data, hydro and aviation products, watches, special weather, and warnings and advisories for that state. Lightning safety tips, interactive games and puzzles, related weather games and puzzles, weather quizzes, outline maps of the continents and parts of the United States, and links to other sites can be found. Students can email the author with questions.

Scatterfield, Dan

2007-12-12

452

Metamorphic Rock Identification  

NSDL National Science Digital Library

In this activity students develop skill in the visual identification of metamorphic rock species and conceptualize the relationships between non-metamorphosed species and their metamorphic counterparts. Students will use a hand lens to examine metamorphic rocks and make observations about grain size, foliation, and other characteristics. Then, using this data, they identify the rocks with the classification sheet included with the student worksheet. They will then match the metamorphic rock with its parent rock.

453

Science Shorts: Organizing Weather Data  

NSDL National Science Digital Library

Often in schools, children collect weather data as part of their morning meeting or calendar time. These common primary level activities lend themselves nicely to introducing the importance of organizing data. In this lesson, children and teacher work together to find a structure for recording precipitation, temperature, and other weather information. Older children compare how using different types of graphs changes what is communicated about their weather data.

Davis, Kimberly J.; Coskie, Tracy L.

2009-01-01

454

Public Awareness of Space Weather  

Microsoft Academic Search

As society increasingly relies on space-based infrastructure for communication and national security, there is a growing need to improve public awareness of the risks space weather poses. The National Space Weather Program (NSWP) should consider this need as it develops new strategic plans. The 2006 ``Report of the Assessment Committee for the National Space Weather Program'' (http:\\/\\/www.ofcm.gov\\/r24\\/fcm-r24.htm) continues to guide

Louis J. Lanzerotti

2009-01-01

455

Weather, Chinook, and Stroke Occurrence  

Microsoft Academic Search

Background—Changes in weather and season have been linked to stroke occurrence. However, the association has been inconsistent across stroke types. Calgary is a city in the Chinook belt and is subject to high variability in weather conditions. Methods—We obtained hourly weather data over a 5-year period from 1996 to 2000; Chinook events were identified according to the accepted definition. We

Thalia S. Field; Michael D. Hill

2010-01-01

456

Salt Attack on Rocks and Expansion of Soils on Mars  

Microsoft Academic Search

Salt-rich sediments observed by the MER rover Opportunity at Meridiani Planum show that brines have been present on Mars in the past, but a role for groundwater in widespread rock weathering and soil formation is uncertain. Experiments by several groups suggest instead the action of acid fog over long time spans, with episodic input of volcanic gases, as a more

D. T. Vaniman; D. L. Bish; S. J. Chipera; J. W. Carey

2004-01-01

457

Microbial populations and activities in the rhizoplane of rock ...  

Treesearch

These desert plants are responsible for rock weathering in an ancient lava flow at La ... OCR (Optical Character Recognition) and therefore does not have any errors in the text. ... View and Print the PRISTINE copy of this Publication (4.3 MB) ... This article was written and prepared by U.S. Government employees on official ...

458

Orbital Identification of Carbonate-Bearing Rocks on Mars  

Microsoft Academic Search

Carbonate is an expected weathering product of basalt in an aqueous environment and an atmosphere with CO2. Its absence in rocks examined by numerous orbiting and landed instruments and its presence as only a very minor phase in Martian meteorites and dust has been proposed to imply that either ancient Mars\\

B. L. Ehlmann; J. F. Mustard; S. L. Murchie; F. Poulet; J. L. Bishop

2008-01-01

459

Weatherization Apprenticeship Program  

SciTech Connect

Weatherization improvement services will be provided to Native people by Native people. The proposed project will recruit, train and hire two full-time weatherization technicians who will improve the energy efficiency of homes of Alaska Natives/American Indians residing in the Indian areas, within the Cook Inlet Region of Alaska. The Region includes Anchorage as well as 8 small tribal villages: The Native Villages of Eklutna, Knik, Chickaloon, Seldovia, Ninilchik, Kenaitze, Salamatof, and Tyonek. This project will be a partnership between three entities, with Cook Inlet Tribal Council (CITC) as the lead agency: CITCA's Employment and Training Services Department, Cook Inlet Housing Authority and Alaska Works Partnership. Additionally, six of the eight tribal villages within the Cook Inlet Region of Alaska have agreed to work with the project in order to improve the energy efficiency of their tribally owned buildings and homes. The remaining three villages will be invited to participate in the establishment of an intertribal consortium through this project. Tribal homes and buildings within Anchorage fall under Cook Inlet Region, Inc. (CIRI) tribal authority.

Watson, Eric J

2012-12-18

460

Vodcasting Space Weather  

NASA Astrophysics Data System (ADS)

The topic of space weather is the subject of a series of vodcasts (video podcasts) produced by MIT Haystack Observatory (Westford, MA) and Loch Ness Productions (Groton, MA). This paper discusses the production and distribution of the series via Webcast, Youtube, and other avenues. It also presents preliminary evaluation of the effectiveness and outreach of the project through feedback from both formal and information education venues. The vodcast series is linked to the NASA Living With a Star Targeted Research and Technology project award "Multi-Instrument Investigation of Inner-Magnetospheric/Ionosphere Disturbances.” It is being carried out by Principal Investigator Dr. John Foster, under the auspices of NASA Grant # NNX06AB86G. The research involves using ionospheric total electron content (TEC) observations to study the location, extent, and duration of perturbations within stormtime ionospheric electric fields at mid- to low latitudes. It combines ground-based global positioning system (GPS) TEC data, incoherent scatter radar measurements of the mid-latitude ionospheric state, and DMSP satellite observations to characterize conditions which lead to severe low-latitude ionospheric perturbations. Each vodcast episode covers a certain aspect of space weather and the research program.

Collins Petersen, Carolyn; Erickson, P. J.; Needles, M.

2009-01-01

461

Met Office: Weather and Climate  

NSDL National Science Digital Library

The United Kingdom's MET office created this website to provide users with weather and climate information for the British Isles and the world. Travelers can find out the latest weather forecasts and general climate patterns for various cities and countries. Users can enjoy the satellite imagery of weather patterns for the continents and the earth. Residents can view animations of the latest rainfall in the United Kingdom. The website provides resourceful materials and illustrations on typhoons and hurricanes. Everyone can read about the latest, strange weather occurrences around the world.

462

Bishop Paiute Weatherization Training Program  

SciTech Connect

The DOE Weatherization Training Grant assisted Native American trainees in developing weatherization competencies, creating employment opportunities for Bishop Paiute tribal members in a growing field. The trainees completed all the necessary training and certification requirements and delivered high-quality weatherization services on the Bishop Paiute Reservation. Six tribal members received all three certifications for weatherization; four of the trainees are currently employed. The public benefit includes (1) development of marketable skills by low-income Native individuals, (2) employment for low-income Native individuals in a growing industry, and (3) economic development opportunities that were previously not available to these individuals or the Tribe.

Carlos Hernandez

2010-01-28

463

Space weather: science and effects  

NASA Astrophysics Data System (ADS)

From the point-of-view of somebody standing outside on a cold winter night looking up at a clear cloudless sky, the space environment seems to be of a peaceful and stable nature. Instead, the opposite is found to be true. In fact the space environment is very dynamic on all spatial and temporal scales, and in some circumstances may have unexpected and hazardous effects on technology and humans both in space and on Earth. In fact the space environment seems to have a weather all of its own - its own “space weather”. Our Sun is definitely the driver of our local space weather. Space weather is an interdisciplinary subject covering a vast number of technological, scientific, economic and environmental issues. It is an application-oriented discipline which addresses the needs of “space weather product” users. It can be truly said that space weather affects everybody, either directly or indirectly. The aim of this paper is to give an overview of what space weather encompasses, emphasizing how solar-terrestrial physics is applied to space weather. Examples of “space weather product” users will be given highlighting those products that we as a civilization are most dependent on.

Crosby, Norma B.

2009-03-01

464

Atomic force microscopy of differential weathering in real time  

SciTech Connect

Differential weathering of a rock sample was observed in-situ using atomic force microscopy (AFM). The samp