Earth Sciences Commons^™

The Hydrogeologic Information In Cross-Borehole Complex Conductivity Data From An Unconsolidated Conglomeratic Sedimentary Aquifer, Andrew Binley, John Keery, Lee Slater, Warren Barrash, Mike Cardiff

Geosciences Faculty Publications and Presentations

Accurate estimation of the hydrological properties of near-surface aquifers is important because these properties strongly influence groundwater flow and solute transport. Laboratory-based investigations have indicated that induced polarization (IP) properties of porous media may be linked, through either semi-empirical or fully mechanistic models, to hydrological properties including hydraulic conductivity. Therefore, there is a need for field assessments of the value of IP measurements in providing insights into the hydrological properties of aquifers. A cross-borehole IP survey was carried out at the Boise Hydrogeophysical Research Site (BHRS), an unconsolidated fluvial aquifer that has previously been well-studied with a variety of geophysical …

Middle Permian U-Pb Zircon Ages Of The "Glacial" Deposits Of The Atkan Formation, Ayan-Yuryakh Anticlinorium, Magadan Province, Ne Russia: Their Significance For Global Climatic Interpretations, V. I. Davydov, A. S. Biakov, J. L. Isbell, J. Crowley, M. D. Schmitz, I. L. Vedernikov

Geosciences Faculty Publications and Presentations

The Atkan Formation in the Ayan-Yuryakh anticlinorium, Magadan province, northeastern Russia, is of great interest because of the occurrence of deposits of apparent “dropstones” and “ice rafted debris” that have been previously interpreted as glacial. Two high-precision U-Pb zircon ages, one for an intercalated volcanic tuff (262.5 ± 0.2 Ma) and the other for a boulder clast (269.8 ± 0.1 Ma) within a diamictite of the Atkan Formation, constrain the age of the Atkan Formation as Guadalupian (middle Permian). Sedimentologic study of the Atkan Formation casts doubt on the glacial nature of the diamictites. Deposition of rocks of the Atkan …

Biotic Paleothermometry Constrains On Arctic Plates Reconstructions: Carboniferous And Permian (Zhokhov Island, De-Longa Group Islands, New Siberian Archipelago), Vladimir I. Davydov

Geosciences Faculty Publications and Presentations

A warm-water fauna and flora from a Carboniferous limestone xenolith that was captured during penetration of deep intraplate Cenozoic basalts through a Paleozoic carbonate platform have been found on Zhokhov Island, New Siberian Archipelago (NSA). This limestone xenolith contains a very high taxonomic diversity of Moscovian (Middle Pennsylvanian) tropical foraminifera and calcareous algae. As this warm-water biota never occurs north of the forbiddance line, i.e., 30–35°N/S, this fauna and algal flora constrain the paleogeography and interpretation of the paleotectonics in the region. Thus, the location of the most of the New Siberian Archipelago islands at that time must have been …

Isolating Retrograde And Prograde Rayleigh-Wave Modes Using A Polarity Mute, Gabriel Gribler, Lee M. Liberty, T. Dylan Mikesell, Paul Michaels

Geosciences Faculty Publications and Presentations

Estimates of S-wave velocity with depth from Rayleigh-wave dispersion data are limited by the accuracy of fundamental and/or higher mode signal identification. In many scenarios, the fundamental mode propagates in retrograde motion, whereas higher modes propagate in prograde motion. This difference in particle motion (or polarity) can be used by joint analysis of vertical and horizontal inline recordings. We have developed a novel method that isolates modes by separating prograde and retrograde motions; we call this a polarity mute. Applying this polarity mute prior to traditional multichannel analysis of surface wave (MASW) analysis improves phase velocity estimation for fundamental and …

Linking In Situ Lai And Fine Resolution Remote Sensing Data To Map Reference Lai Over Cropland And Grassland Using Geostatistical Regression Method, Yaqian He, Yanchen Bo, Leilei Chai, Xiaolong Liu, Aihua Li

Geosciences Faculty Publications and Presentations

Leaf Area Index (LAI) is an important parameter of vegetation structure. A number of moderate resolution LAI products have been produced in urgent need of large scale vegetation monitoring. High resolution LAI reference maps are necessary to validate these LAI products. This study used a geostatistical regression (GR) method to estimate LAI reference maps by linking in situ LAI and Landsat TM/ETM+ and SPOT-HRV data over two cropland and two grassland sites. To explore the discrepancies of employing different vegetation indices (VIs) on estimating LAI reference maps, this study established the GR models for different VIs, including difference vegetation index …

Isotopic Evidence For Lateral Flow And Diffusive Transport, But Not Sublimation, In A Sloped Seasonal Snowpack, Idaho, Usa, Samantha L. Evans, Alejandro N. Flores, Achim Heilig, Matthew J. Kohn, Hans-Peter Marshall, James P. Mcnamara

Geosciences Faculty Publications and Presentations

Oxygen and hydrogen isotopes in snow were measured in weekly profiles during the growth and decline of a sloped subalpine snowpack, southern Idaho, 2011–2012. Isotopic steps (10‰, δ¹⁸O; 80‰, δD) were preserved relative to physical markers throughout the season, albeit with some diffusive smoothing. Melting stripped off upper layers without shifting isotopes within the snowpack. Meltwater is in isotopic equilibrium with snow at the top but not with snow at each respective collection height. Transport of meltwater occurred primarily along pipes and lateral flow paths allowing the snowpack to melt initially in reverse stratigraphic order. Isotope diffusivities are …

Aquifer Arsenic Cycling Induced By Seasonal Hydrologic Changes Within The Yangtze River Basin, Michael V. Schaefer, Samantha C. Ying, Shawn G. Benner, Yanhua Duan, Yanxin Wang, Scott Fendorf

Geosciences Faculty Publications and Presentations

Consumption of groundwater containing >10 μg L⁻¹ arsenic (As) adversely impacts more than 100 million people worldwide. Multiyear trends in aquifer As concentrations have been documented, but strong seasonal variations are not commonly observed. Here we report dramatic seasonal changes in As concentrations and aquifer chemistry within the Jianghan Plain of the Yangtze River, China. At some wells, concentrations fluctuate by more than an order of magnitude within a single year (100−1200 μg L⁻¹). Groundwater extraction and sustained water levels of surface channels during the dry season induces a strong downward hydraulic gradient, seasonally supplying …

Zircon U-Pb Ages And Hf Isotopes Of The Askot Klippe, Kumaun, Northwest India: Implications For Paleoproterozoic Tectonics, Basin Evolution And Associated Metallogeny Of The Northern Indian Cratonic Margin, Subhadip Mandal, Delores M. Robinson, Matthew J. Kohn, Subodha Khanal, Oindrila Das, Sukhanjan Bose

Geosciences Faculty Publications and Presentations

Throughout the Himalayan thrust belt, klippen of questionable tectonostratigraphic affinity occur atop Lesser Himalayan rocks. Integrated U-Pb ages, Hf isotopic, and whole rock trace element data establish that the Askot klippe, in northwest India, is composed of Paleoproterozoic lower Lesser Himalayan rocks, not Greater Himalayan rocks, as previously interpreted. The Askot klippe consists of 1857 ± 19 Ma granite-granodiorite gneiss, coeval 1878 ± 19 Ma felsic volcanic rock, and circa 1800 Ma Berinag quartzite, representing a small vestige of a Paleoproterozoic (circa 1850 Ma) continental arc, formed on northern margin of the north Indian cratonic block. Detrital zircon from Berinag …

Evaluation Of Glaciogenic Cloud Seeding Using Trace Chemistry, James M. Fisher, Marion L. Lytle, Shawn G. Benner

Geosciences Faculty Publications and Presentations

Glaciogenic cloud seeding with silver iodide (AgI) has been used to enhance precipitation for over 60 years. Assessments of AgI impact and dispersion are often quantified using atmospheric processes models with impact assessed by comparing models with and without the inclusion of cloud seeding modules. However, there is inherent uncertainty in these models. Quantifying AgI distribution in the snowpack following cloud seeding can both validate and improve model performance. The purpose of this study is to demonstrate the capacity to document the dispersion of AgI by measuring silver (Ag) enrichments in snow.

This study develops clean field and laboratory procedures …

Carbon Isotope Discrimination In C3 Land Plants Is Independent Of Natural Variations In PCo2, M. J. Kohn

Geosciences Faculty Publications and Presentations

The δ¹³C of terrestrial C3 plant tissues and soil organic matter is important for understanding the carbon cycle, inferring past climatic and ecological conditions, and predicting responses of vegetation to future climate change. Plant δ¹³C depends on the δ¹³C of atmospheric CO₂ and and mean annual precipitation (MAP), but an unresolved decades-long debate centres on whether terrestrial C3 plant δ¹³C responds to p_CO2. In this study, the p_CO2-dependence of C3 land plant δ¹³C was tested using isotopic records from low- and high-p_{CO …}

Targeted Reflection-Waveform Inversion Of Experimental Ground-Penetrating Radar Data For Quantification Of Oil Spills Under Sea Ice, John H. Bradford, Esther L. Babcock, Hans-Peter Marshall, David F. Dickins

Geosciences Faculty Publications and Presentations

Rapid spill detection and mapping are needed with increasing levels of oil exploration and production in the Arctic. Previous work has found that ground-penetrating radar (GPR) is effective for qualitative identification of oil spills under, and encapsulated within, sea ice. Quantifying the spill distribution will aid effective spill response. To this end, we have developed a targeted GPR reflection-waveform inversion algorithm to quantify the geometry of oil spills under and within sea ice. With known electric properties of the ice and oil, we have inverted for oil thickness and variations in ice thickness. We have tested the algorithm with data …

Re-Assessment Of Lithostratigraphy, Biostratigraphy, And Volcanic Activity Of The Late Paleozoic Intra-Sudetic, Krkonoše-Piedmont And Mnichovo Hradiště Basins (Czech Republic) Based On New U-Pb Ca-Id-Tims Ages, Stanislav Opluštil, Mark Schmitz, Václav Kachlík, Stanislav Štamberg

Geosciences Faculty Publications and Presentations

Five U-Pb CA-ID-TIMS high-precision ages were obtained from single zircon crystals separated from tuffs or ignimbrites embedded in Pennsylvanian to Asselian sediments of the Intra-Sudetic, Krkonoše-Piedmont and the adjacent part of the Mnichovo Hradiště basins. The new radioisotopic data are used for extrapolation of ages of dated lithostratigraphic units. The existing borehole network in the Late Paleozoic continental basins of central and western Bohemia and in the Sudetic area, and similarity of their stratigraphically equivalent strata including some common lacustrine horizons allow a detailed lithostratigraphical correlation between these two areas. This in turn, allows combining our new radioisotopic data with …

Muang Rae Geothermal System: Drilling And Borehole Geophysics, 1000-M Core Hole Into Granitic Rock, Amphoe Pai, Mae Hong Son Province, Northern Thailand, Spencer H. Wood, Kriangsak Pirarai, Aranya Fuangswasdi, Wiboon Kaentao, Albert Waibel, Fongsaward S. Singharajwarapan

Geosciences Faculty Publications and Presentations

In 2015, a 1-km core hole was drilled into granitic rock at the Muang Rae geothermal area. Previous drilling in 1993 to 200 m was unsuccessful in obtaining flows, but one of the “dry” wells began flowing in August, 2013 at 9.75 L/s of 96.9°C water from a fracture zone 80 m deep. In the sandy bed of the Pai River, 150 m south of that well is a 600-m long line of hot seeps, oriented NE, with highest temperature measured at 94.5°C. Geology is foliated Triassic (?) granitic rock cut by a NE-SW-trending normal fault zone (dip 65° NW) …