Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Geology

Geosciences Faculty Publications

2017

Articles 1 - 8 of 8

Full-Text Articles in Physical Sciences and Mathematics

Effect Of An 860-M Thick, Cold, Freshwater Aquifer On Geothermal Potential Along The Axis Of The Eastern Snake River Plain, Idaho, Thomas E. Lachmar, Thomas G. Freeman, Christopher J. Sant, Jeffrey R. Walker, Joseph F. Batir, John W. Shervais, James P. Evans, Dennis L. Nielson, David D. Blackwell Dec 2017

Effect Of An 860-M Thick, Cold, Freshwater Aquifer On Geothermal Potential Along The Axis Of The Eastern Snake River Plain, Idaho, Thomas E. Lachmar, Thomas G. Freeman, Christopher J. Sant, Jeffrey R. Walker, Joseph F. Batir, John W. Shervais, James P. Evans, Dennis L. Nielson, David D. Blackwell

Geosciences Faculty Publications

A 1912-m exploration corehole was drilled along the axis of the eastern Snake River Plain, Idaho. Two temperature logs run on the corehole display an obvious inflection point at about 960 m. Such behavior is indicative of downward fluid flow in the wellbore. The geothermal gradient above 935 m is 4.5 °C/km, while the gradient is 72–75 °C/km from 980 to 1440 m. Projecting the higher gradients upward to where they intersect the lower gradient on the temperature logs places the bottom of the cold, freshwater Snake River Plain aquifer, which suppresses the geothermal gradient at this location, at least …

Go to article

Usarray Imaging Of Continental Crust In The Conterminous United States, Xiaofei Ma, Anthony R. Lowry Dec 2017

Usarray Imaging Of Continental Crust In The Conterminous United States, Xiaofei Ma, Anthony R. Lowry

Geosciences Faculty Publications

The thickness and bulk composition of continental crust provide important constraints on the evolution and dynamics of continents. Crustal mineralogy and thickness both may influence gravity anomalies, topographic elevation, and lithospheric strength, but prior to the inception of EarthScope’s USArray, seismic measurements of crustal thickness and properties useful for inferring lithology are sparse. Here we improve upon a previously published methodology for joint inversion of Bouguer gravity anomalies and seismic receiver functions by using parameter space stacking of cross correlations of modeled synthetic and observed receiver functions instead of standard H-κ amplitude stacking. The new method is applied to estimation …

Go to article

High-Pressure Granulite Facies Overprinting During The Exhumation Of Eclogites In The Bangong-Nujiang Suture Zone, Central Tibet: Link To Flat-Slab Subduction, Xiu Zheng Zhang, Qiang Wang, Yong Sheng Dong, Chunfu Zhang, Qing Yun Li, Xiao Ping Xia, Wang Xu Dec 2017

High-Pressure Granulite Facies Overprinting During The Exhumation Of Eclogites In The Bangong-Nujiang Suture Zone, Central Tibet: Link To Flat-Slab Subduction, Xiu Zheng Zhang, Qiang Wang, Yong Sheng Dong, Chunfu Zhang, Qing Yun Li, Xiao Ping Xia, Wang Xu

Geosciences Faculty Publications

The geometric transformation of a descending plate, such as from steep to flat subduction in response to a change from normal to overthickened oceanic crust during subduction, is a common and important geological process at modern or fossil convergent margins. However, the links between this process and the metamorphic evolution of the exhumation of oceanic (ultra)high-pressure eclogites are poorly understood. Here we report detailed petrological, mineralogical, phase equilibria, and secondary ion mass spectrometry zircon and rutile U-Pb age data for the Dong Co eclogites at the western segment of the Bangong-Nujiang suture zone, central Tibet. Our data reveal that the …

Go to article

Re–Os Isotope Geochronology Of The Shangbao Pyrite–Flourite Deposit In Southeastern Hunan, South China: Evidence For Multiple Mineralization Events And The Role Of Crust–Mantle Interaction In Polymetallic Deposits, Cheng Cheng Huang, Hai Feng Guo, Jie Li, Qiang Wang, Chunfu Zhang, Derek Wyman, Gong Jian Tang Dec 2017

Re–Os Isotope Geochronology Of The Shangbao Pyrite–Flourite Deposit In Southeastern Hunan, South China: Evidence For Multiple Mineralization Events And The Role Of Crust–Mantle Interaction In Polymetallic Deposits, Cheng Cheng Huang, Hai Feng Guo, Jie Li, Qiang Wang, Chunfu Zhang, Derek Wyman, Gong Jian Tang

Geosciences Faculty Publications

In South China, both crustal reworking and crust–mantle interaction were important geological processes during the Paleozoic and Mesozoic eras. However, the relationships between these two processes and metal mineralization are still unknown. Here we report rhenium and osmium isotopic data for pyrite grains from a pyrite deposit associated with a granite intrusion in the Shangbao area, southeastern Hunan Province (South China). Two pyrite samples, both containing many euhedral pyrite grains, were collected from the same locality, but the samples yield distinct ages. Six euhedral pyrite grains from one sample yield an isochronal age of 279 ± 12 Ma, with an …

Go to article

Controls On Erosion In The Western Tarin Basin: Implications For The Uplift Of Northwest Tibet And The Parmir, Peter D. Clift, Hongbo Zheng, Andrew Carter, Philipp Böning, Tara N. Jonell, Hannah Schorr, Xin Shan, Katharina Pahnke, Xiaochun Wei, Tammy M. Rittenour Aug 2017

Controls On Erosion In The Western Tarin Basin: Implications For The Uplift Of Northwest Tibet And The Parmir, Peter D. Clift, Hongbo Zheng, Andrew Carter, Philipp Böning, Tara N. Jonell, Hannah Schorr, Xin Shan, Katharina Pahnke, Xiaochun Wei, Tammy M. Rittenour

Geosciences Faculty Publications

We present here bulk sediment major element chemistry, Nd and Sr isotope ratios, and detrital apatite fission-track (AFT) and U-Pb zircon ages to characterize the provenance of the southwestern Taklimakan Desert (northwest China) and the three major rivers draining this region. We establish the spatial and temporal controls on erosion and sediment transport in the modern Tibetan rain shadow. The Hotan River drains the North Kunlun block and is characterized by zircon populations at 160–230 Ma and 370–520 Ma. The Yarkand River shares these grains with the Hotan, but also has a very prominent zircon population at 40–160 Ma, which …

Go to article

Single-Grain Optically Stimulated Luminescence Ages Of Brownware Pottery In The Central Rocky Mountains And The Spread Of Numic Ceramic Technology, Judson Byrd Finley, Carlie J. Ideker, Tammy M. Rittenour Aug 2017

Single-Grain Optically Stimulated Luminescence Ages Of Brownware Pottery In The Central Rocky Mountains And The Spread Of Numic Ceramic Technology, Judson Byrd Finley, Carlie J. Ideker, Tammy M. Rittenour

Geosciences Faculty Publications

This study presents the results of a single-grain optically stimulated luminescence (SG-OSL) analysis of brownware pottery from four Late Prehistoric-period sites in the Middle Rocky Mountains, Wyoming, USA. SG-OSL of quartz ceramic temper provides improved age control for sites where radiocarbon dating has proven problematic due to old wood, recent wildfires, and calibration uncertainties. SG-OSL results are compared to fine-grain infrared stimulated luminescence (FG-IRSL) results from the same sherds and associated radiocarbon ages. We find that the single-grain technique applied to quartz sand temper provides improved accuracy and precision over both FG-IRSL and radiocarbon. We compare our results to directly …

Go to article

What Causes People To Change Their Opinion About Climate Change?, Risa Palm, Gregory B. Lewis, Bo Feng Mar 2017

What Causes People To Change Their Opinion About Climate Change?, Risa Palm, Gregory B. Lewis, Bo Feng

Geosciences Faculty Publications

After a decade of steady growth in the acceptance of the existence of climate change and its anthropogenic causes, opinions have polarized, with almost one-third of Americans, mostly Republicans, denying that the climate is changing or that human activity is responsible. What causes Americans to change their minds on this issue? Using a large panel data set, we examined the impacts of direct experience with weather anomalies, ideology, relative prioritization of environmental conservation in comparison to economic development, and motivated reasoning that adjusts individual opinion to align with others who share one’s party identification. A generalized ordered logit model confirmed …

Go to article

User Guide For Luminescence Sampling In Archaeological And Geological Context, Michelle C. Summa-Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon A. Mahan Jan 2017

User Guide For Luminescence Sampling In Archaeological And Geological Context, Michelle C. Summa-Nelson, Harrison J. Gray, Jack A. Johnson, Tammy M. Rittenour, James K. Feathers, Shannon A. Mahan

Geosciences Faculty Publications

Luminescence dating provides a direct age estimate of the time of last exposure of quartz or feldspar minerals to light or heat and has been successfully applied to deposits, rock surfaces, and fired materials in a number of archaeological and geological settings. Sampling strategies are diverse and can be customized depending on local circumstances, although all sediment samples need to include a light-safe sample and material for dose-rate determination. The accuracy and precision of luminescence dating results are directly related to the type and quality of the material sampled and sample collection methods in the field. Selection of target material …

Go to article