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Full-Text Articles in Geology

Millard Et Al. Pressure Dependence Of Magnesite Creep 2019 Geosciences.Pdf, Caleb Holyoke Sep 2019

Millard Et Al. Pressure Dependence Of Magnesite Creep 2019 Geosciences.Pdf, Caleb Holyoke

Caleb Holyoke

No abstract provided.


Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya Mar 2019

Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya

Umesh K. Haritashya

Meltwater runoff modeling from glacierized basins needs several input data, including total meltwater contributing area. This study utilizes optical remote sensing data to assess glacierized basins in the central Himalayas where snow and glaciers contribute substantially to the water resources. Result shows that there are four main water-bearing zones in the basin: (a) dry snow, (b) wet snow, (c) exposed glacial ice, and (d) debris-covered glacial ice, and it is possible to differentiate and map these zones and their spatio-temporal variations from satellite sensor data. These zones can then be incorporated in meltwater runoff modeling as separate entities because they …


Effects Of Changes In Moisture Source And The Upstream Rainout On Stable Isotopes In Precipitation – A Case Study In Nanjing, Eastern China, Y. Tang, H. Pang, W. Zhang, Y. Li, Shuang-Ye Wu, S. Hou Apr 2016

Effects Of Changes In Moisture Source And The Upstream Rainout On Stable Isotopes In Precipitation – A Case Study In Nanjing, Eastern China, Y. Tang, H. Pang, W. Zhang, Y. Li, Shuang-Ye Wu, S. Hou

Shuang-ye Wu

In the Asian monsoon region, variations in the stable isotopic composition of speleothems have often been attributed to the "amount effect". However, an increasing number of studies suggest that the "amount effect" in local precipitation is insignificant or even non-existent. To explore this issue further, we examined the variability of daily stable isotopic composition (δ18O) in precipitation from September 2011 to November 2014 in Nanjing, eastern China. We found that intra-seasonal variations of δ18O during summer were not significantly correlated with local rainfall amount but could be linked to changes in the moisture source location and rainout processes in the …


Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu Apr 2016

Reconstruction Of The Hirnantian (Late Ordovician) Palaeotopography In The Upper Yangtze Region, Linna Zhang, Junxuan Fan, Qing Chen, Shuang-Ye Wu

Shuang-ye Wu

Reconstruction of the Hirnantian (Late Ordovician) palaeotopography in South China is important for understanding the distribution pattern of the Hirnantian marine depositional environment. In this study, we reconstructed the Hirnantian palaeotopography in the Upper Yangtze region based on the rankings of the palaeo-water depths, which were inferred according to the lithofacies and biofacies characteristics of the sections. Data from 374 Hirnantian sections were collected and standardized through the online Geobiodiversity Database. The Ordinary Kriging interpolation method in the ArcGIS software was applied to create the continuous surface of the palaeo-water depths, i.e. the Hirnantian palaeotopography. Meanwhile, the line transect analysis …


Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland Apr 2016

Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland

Allen J. McGrew

New mapping, structural analysis, and 40Ar/39Ar dating reveal an unusually well‐constrained history of Late Eocene extension in the Copper Mountains of the northern Basin and Range province. In this area, the northeast‐trending Copper Creek normal fault juxtaposes a distinctive sequence of metacarbonate and granitoid rocks against a footwall of Upper Precambrian to Lower Cambrian quartzite and phyllite. Correlation of the hanging wall with footwall rocks to the northwest provides an approximate piercing point that requires 8–12 km displacement in an ESE direction. This displaced fault slice is itself bounded above by another normal fault (the Meadow Fork Fault), which brings …


Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar Mar 2016

Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar

Umesh K. Haritashya

Meteorological data collected near the snout of the Gangotri Glacier suggest that the study area receives less rainfall. The average seasonal rainfall is observed to be about 260 mm. The rainfall distribution does not show any monsoon impact. Amount of seasonal rainfall is highly variable (131.4-368.8 mm) from year to year, but, in general, August had the maximum rainfall. A verage daily maximum and minimum temperatures were 14.7 and 4.1°C respectively, whereas average mean temperature was 9.4°C. July was recorded as the warmest month. During daytime, wind speed was four times higher than that at night-time. The average daytime and …


Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe Mar 2016

Multispectral Image Analysis Of Glaciers And Glacier Lakes In The Chugach Mountains, Alaska, Jeffrey Kargel, Matthew Beedle, Andrew Bush, Francisco Carreño, Elena Castellanos, Umesh Haritashya, Gregory Leonard, Javier Lillo, Ivan Lopez, Mark Pleasants, Edward Pollock, David Wolfe

Umesh Haritashya

The Chugach Mountains contain the largest nonpolar alpine glaciers in the world and include a wide variety of glacier types: some are land terminating; some calve variously into tidewater, lakes, and rivers; some are heavily debris covered; some are surge-type, whereas others are neither debris covered nor surge type. Nearly all are retreating, thinning, or both, though some rare ones are advancing, and some are thickening at high elevations. To assist the further documentation of changes, we establish an inventory of glaciers in the eastern Chugach Mountains. Several case studies of diverse glacier types showcase remotesensing applications and are used …


Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya Mar 2016

Encyclopedia Of Snow, Ice And Glaciers, Vijay P. Singh, Pratap Singh, Umesh K. Haritashya

Umesh K. Haritashya

The objective of this encyclopedia is to present the current state of scientific understanding of various aspects of earth’s cryosphere – snow, glaciers, ice caps, ice sheets, ice shelves, sea ice, river and lake ice, and permafrost – and their related interdisciplinary connections under one umbrella. Therefore, every effort has been made to provide a comprehensive coverage of cryosphere by including a broad array of topics, such as the atmospheric processes responsible for snow formation; snowfall observations; snow cover and snow surveys; transformation of snow to ice and changes in their properties; classification of ice and glaciers and their worldwide …


Appendix A: Borehole Data (Thesis Appendix, 2013), David J. Richey Dec 2012

Appendix A: Borehole Data (Thesis Appendix, 2013), David J. Richey

David J Richey

Select borehole data compiled and organized from Utah Division Oil, Gas and Mining (www.oilgas.ogm.utah.gov). The data found here include API well numbers, names of all wells used, well datum as defined by the elevation above sea level measured at the Kelly Bushing on the drilling floor, and the depth to various formation tops encountered during drilling measured in drilling depth.


Appendix B: Geophysical Data (Thesis Appendix, 2013), David J. Richey Dec 2012

Appendix B: Geophysical Data (Thesis Appendix, 2013), David J. Richey

David J Richey

Select geophysical data collected and processed during this thesis. A description of the geophysical methods used, the results and raw data, and some interpretations are provided in this appendix.


Forward Modeling Synsedimentary Deformation Associated With A Prograding Steep-Sloped Carbonate Margin, Phillip G. Resor Dec 2009

Forward Modeling Synsedimentary Deformation Associated With A Prograding Steep-Sloped Carbonate Margin, Phillip G. Resor

Phillip G Resor

Differential compaction associated with prograding and aggrading steep-rimmed carbonate margins leads to penecontemporaneous and post- depositional modifications of stratal geometries and tensile and shear stress concentrations that result in brittle deformation. In an effort to investigate controls on these deformation processes, we employ a step-wise gravity loaded elastic model that captures pre-failure displacement and stress field patterns for a depositional geometry based on the Permian Capitan depositional system, Guadalupe Mountains, West Texas and New Mexico, USA. We consider four model geometries with varying progradation to aggradation (P/A) ratio, from strongly prograding (P/A=10) to strongly aggrading (P/A=0.1). The strongly prograding case …


The Biscayne Aquifer Of Southeastern Florida, Kevin Cunningham, Lee J. Florea Jun 2009

The Biscayne Aquifer Of Southeastern Florida, Kevin Cunningham, Lee J. Florea

Lee J Florea, PhD, P.G.

In southeastern Florida, locally delineated, small, poorly explored caves and subtle karst are characteristic of the limestone that composes the unconfined Biscayne aquifer – one of the most permeable aquifers in the world. The main units of the Biscayne aquifer are the Fort Thompson Formation and Miami Limestone, both characterized by eogenetic karst.


Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer Dec 2008

Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer

Phillip G Resor

Slip heterogeneity reflects the fundamental physics of earthquake rupture and has been attributed to strong fault patches termed asperities or barriers. We propose that variations in fault-surface orientation due to slip-parallel corrugations may act as geometric asperities and barriers, generating variations in incremental (i.e. due to a single earthquake) slip across a fault surface. We evaluate this hypothesis using observations from the Arkitsa normal fault exposure in central Greece. A scan of the Arkitsa fault surface with 1-m spatial resolution and mm-scale precision reveals corrugations made up of 1–5 m wide synforms, antiforms, and nearly planar fault sections with long …


In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant Dec 2006

In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant

Donald J. Kochan

Significant research has been conducted into the utilization of geothermal resources as a ‘green’ energy source. However, minimal research has been conducted into geothermal resource utilization and depletion impacts on thermophile biodiversity. Thermophiles are organisms which have adapted over millions of year to extreme temperature and chemical compositions and exist in hot springs and other geothermal resources. Their ability to withstand high temperatures makes them invaluable to scientific and medical research. Current federal and California case law classify geothermal resources as a mineral, not a water resource. Acquisition of rights to develop a geothermal resource owned or reserved by the …


The Karst Of West-Central Florida, Lee J. Florea Aug 2006

The Karst Of West-Central Florida, Lee J. Florea

Lee J Florea, PhD, P.G.

Caves, the cornerstone feature of karst aquifers, are little understood in Florida. This dissertation, which analyzes the morphology, elevation, lithologic setting, and hydrology of caves in west-central Florida, demonstrates that the karst of the unconfined Floridan aquifer differs from the paradigm view of karst presented in modern geology textbooks. The differences reflect setting: eogenetic (west-central Florida) vs. telogenetic (conventional).


Constraining The Exhumation And Burial History Of The Safod Pilot Hole With Apatite Fission Track And (U-Th)/He Thermochronometry, Ann Blythe, M D’Alessio, R Bürgmann Jun 2004

Constraining The Exhumation And Burial History Of The Safod Pilot Hole With Apatite Fission Track And (U-Th)/He Thermochronometry, Ann Blythe, M D’Alessio, R Bürgmann

Ann Blythe

[1] The San Andreas Fault Observatory at Depth (SAFOD) pilot hole traverses the upper 2 km of a site 1.8 km west of the San Andreas fault (SAF) near Parkfield, California. In order to evaluate the burial and exhumation history of the site and its relationship to the kinematics and mechanics of the SAF, we use 15 apatite fission-track (FT) and 5 (U-Th)/He analyses from pilot hole samples to document their thermal history. Sample ages decrease with depth: FT and (U-Th)/He ages range from ∼60 and ∼31 Ma, respectively, in the upper 800 m of the hole to ∼3 and …


Subduction Of The Caribbean Plate And Basement Uplifts In The Overriding South American Plate, James N. Kellogg, William E. Bonini May 1982

Subduction Of The Caribbean Plate And Basement Uplifts In The Overriding South American Plate, James N. Kellogg, William E. Bonini

James N Kellogg

Abstract. The new tectonic interpretations presented in this paper are based on geologic field mapping and gravity data supplemented by well logs, seismic profiles, and radiometric and earthquake data. The present Caribbean-South American plate boundary is the South Caribbean marginal fault, where subduction is indicated by folding and thrusting in the deformed belt and a seismic zone that dips 30o to the southeast and terminates 200 km below the Maracaibo Basin. The Caribbean-South American convergence rate is estimated as 1.9 +_. 0.3 cm/yr on the basis of the 390-km length of the seismic zone and a thermal equilibration time of …