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2016

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Full-Text Articles in Physical Sciences and Mathematics

Ironstone Gravel Types In Western Australia: Re-Purposing A Geological Survey To Improve Soil Management, Edward A. Griffin, Karen Holmes, Tim Overheu Dec 2016

Ironstone Gravel Types In Western Australia: Re-Purposing A Geological Survey To Improve Soil Management, Edward A. Griffin, Karen Holmes, Tim Overheu

Conference papers and presentations

The deeply laterised landscapes of Western Australia’s wheatbelt contain large amounts of ferruginous concretions or pisoliths, referred to locally as ironstone gravel. Soil surveys over the years have described ironstone gravel presence and abundance, and the state soil classification system recognises their importance in agriculture by designating ‘ironstone gravel soils’ at the highest level of the classification hierarchy. These gravels have generally been assumed inert in agricultural soils; however, farm trials and anecdotal experience suggest they may play a more active role in nutrient and water retention than previously recognised. Gravelly soil performance under dryland agriculture varies dramatically across the …


Three-Dimensional Modeling Of Pennsylvanian Sandstone Units In The Mature Dudley Oil Field, Illinois, Usa, Jordan M. Martin, David H. Malone Dec 2016

Three-Dimensional Modeling Of Pennsylvanian Sandstone Units In The Mature Dudley Oil Field, Illinois, Usa, Jordan M. Martin, David H. Malone

Faculty Publications-- Geography, Geology, and the Environment

The purpose of this research is to better understand the Dudley Pool, a small, mature oil field in the Illinois Basin, USA by incorporating old geologic and geophysical data into modern petrophysical modeling software. The research focused on three-dimensional subsurface modeling of stratigraphy, structure, and porosity, to establish a more thorough understanding of oil occurrence at the Dudley Pool. This research also discusses the efficacy of three-dimensional modeling as an effective tool for evaluating, and potentially modifying, production efforts in mature petroleum fields with limited and/or poor-quality data. The modeling and calculations were completed using Petrel. Well information from all …


Small-Scale Catchment Analysis Of Water Stress In Wet Regions Of The U.S.: An Example From Louisiana, Hisham Eldardiry, Emad H. Habib, David M. Borrok Dec 2016

Small-Scale Catchment Analysis Of Water Stress In Wet Regions Of The U.S.: An Example From Louisiana, Hisham Eldardiry, Emad H. Habib, David M. Borrok

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Groundwater is increasingly being overdrafted in the Southeastern U.S., despite abundant rainfall and the apparent availability of surface water. Using the state of Louisiana as an example, the current study quantifies the stresses on water resources and investigates the potential for opportunities to use surface water in lieu of groundwater pumping. The assessment is based on a fine watershed scale (12-digit Hydrological Unit Code [HUC] boundaries) water balance between the availability of surface and groundwater and surface water and groundwater demand. Water demand includes environmental flows, as well as public supply, rural domestic, industrial, power generation, agricultural, and aquaculture sectors. …


Ground-Penetrating Radar Water Content Mapping Of Golf Course Green Sand Layers, Barry J. Allred, Robert S. Freeland, Katherine R. Grote, Edward L. Mccoy, Luis R. Martinez, Debra L. Gamble Dec 2016

Ground-Penetrating Radar Water Content Mapping Of Golf Course Green Sand Layers, Barry J. Allred, Robert S. Freeland, Katherine R. Grote, Edward L. Mccoy, Luis R. Martinez, Debra L. Gamble

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Information on the spatial distribution of water content across the sand layer component of a golf course green can be important to golf course superintendents for evaluating drainage effectiveness and scheduling irrigation. To estimate the bulk volumetric water content of the sand layer at point locations across the green, a technique was developed that combined (1) depth (or thickness) of the sand layer measured with a steel shaft tile probe, (2) radar signal two-way travel time from the base of the sand layer obtained using a ground-penetrating radar (GPR) system with 900 MHz antennas, and (3) an empirical equation relating …


Modeling The Effects Of Tile Drain Placement On The Hydrologic Function Of Farmed Prairie Wetlands1, Brett Werner, John Tracy, W. Carter Johnson, Richard A. Voldseth, Glenn R. Guntenspergen, Bruce Millett Dec 2016

Modeling The Effects Of Tile Drain Placement On The Hydrologic Function Of Farmed Prairie Wetlands1, Brett Werner, John Tracy, W. Carter Johnson, Richard A. Voldseth, Glenn R. Guntenspergen, Bruce Millett

United States Geological Survey: Staff Publications

The early 2000s saw large increases in agricultural tile drainage in the eastern Dakotas of North America. Agricultural practices that drain wetlands directly are sometimes limited by wetland protection programs. Little is known about the impacts of tile drainage beyond the delineated boundaries of wetlands in upland catchments that may be in agricultural production. A series of experiments were conducted using the well-published model WETLANDSCAPE that revealed the potential for wetlands to have significantly shortened surface water inundation periods and lower mean depths when tile is placed in certain locations beyond the wetland boundary. Under the soil conditions found in …


Precursor Motion To Iceberg Calving At Jakobshavn Isbræ, Greenland, Observed With Terrestrial Radar Interferometry, Surui Xie, Timothy H. Dixon, Denis Voytenko, David M. Holland, Tiantian Zheng Dec 2016

Precursor Motion To Iceberg Calving At Jakobshavn Isbræ, Greenland, Observed With Terrestrial Radar Interferometry, Surui Xie, Timothy H. Dixon, Denis Voytenko, David M. Holland, Tiantian Zheng

School of Geosciences Faculty and Staff Publications

Time-varying elevations near the calving front of Jakobshavn Isbræ, Greenland were observed with a terrestrial radar interferometer (TRI) in June 2015. An ice block with surface dimensions of 1370 m × 290 m calved on 10 June. TRI-generated time series show that ice elevation near the calving front began to increase 65 h prior to the event, and can be fit with a simple block rotation model. We hypothesize that subsurface melting at the base of the floating terminus breaks the gravity-buoyancy equilibrium, leading to slow subsidence and rotation of the block, and its eventual failure.


Early Miocene Quantitative Calcareous Nannofossil Biostratigraphy From The Tropical Atlantic, Waheed A. Albasrawi Dec 2016

Early Miocene Quantitative Calcareous Nannofossil Biostratigraphy From The Tropical Atlantic, Waheed A. Albasrawi

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Quantitative analysis for the Lower Miocene of Ocean Drilling Program Hole 959A from the West African margin was performed to document all the calcareous nannofossil biostratigraphic events present. Combined with data from previous investigations of the Lower Miocene from the tropical Atlantic, this research identifies and tests the viability of markers used in current zonation scheme, identifies alternative markers for age boundaries, and examine statistically the most probable order of event in the Lower Miocene using the Ranking and Scaling method (RASC).

The examination of Hole 959A was performed on a 112 samples. Seven additional sites that collectively span the …


An Assessment Of Concrete Over Asphalt Pavement Using Both The Ultrasonic Surface Wave And Impact Echo Techniques, Mengxing Li, Neil Lennart Anderson, Lesley Sneed, Xin Kang Dec 2016

An Assessment Of Concrete Over Asphalt Pavement Using Both The Ultrasonic Surface Wave And Impact Echo Techniques, Mengxing Li, Neil Lennart Anderson, Lesley Sneed, Xin Kang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A portable seismic property analyzer (PSPA) was used to simultaneously acquire both ultrasonic surface wave (PSPA-USW) and impact-echo (PSPA-IE) data at predetermined locations along a section of multi-layered pavement. The pavement consisted of a basal concrete layer (~220 mm), an intervening layer of hot-mix asphalt (~60 mm), and a concrete overlay (~220 mm). The section of multi-layered pavement was cored at multiple PSPA test locations for verification purposes. The conditions of the extracted cores were assessed visually, and the static elastic modulus, as well as the compressional wave velocity of each concrete overlay core, were measured in the laboratory. Results …


The Development And Evaluation Of Lecture Tutorials For Introductory Soil Science, Judith K. Turk Dec 2016

The Development And Evaluation Of Lecture Tutorials For Introductory Soil Science, Judith K. Turk

Conservation and Survey Division

The wide-array of concepts from the natural sciences that must be mastered to succeed in an introductory soil science course presents a significant challenge to students. This study was conducted to determine if students’ conceptual development regarding topics in introductory soil science could be improved by using lecture tutorials. Lecture tutorials are activities that students complete following a lecture. They guide the students to critically analyze their understanding of a concept presented in the lecture. Eight lecture tutorials were written and evaluated using pre/post quizzes and surveys in two courses (an environmental science program course and a general studies course). …


Groundwater Declines Are Linked To Changes In Great Plains Stream Fish Assemblages, Joshuah S. Perkin, Keith B. Gido, Jeffrey A. Falke, Kurt D. Fausch, Harry Crockett, Eric R. Johnson, John Sanderson Nov 2016

Groundwater Declines Are Linked To Changes In Great Plains Stream Fish Assemblages, Joshuah S. Perkin, Keith B. Gido, Jeffrey A. Falke, Kurt D. Fausch, Harry Crockett, Eric R. Johnson, John Sanderson

United States Geological Survey: Staff Publications

Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950–2010) and prospective (2011–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish assemblages associated with groundwater pumping from the United States High Plains Aquifer. We modeled the relationship between the length of stream receiving water from the High Plains Aquifer and the occurrence of fishes characteristic of small and large streams in the western Great Plains at a regional scale and for six subwatersheds nested within …


Holocene Glacial Activity In Barilari Bay, West Antarctic Peninsula, Tracked By Magnetic Mineral Assemblages: Linking Ice, Ocean, And Atmosphere, Brendan Reilly, Carl Natter, Stefanie A. Brachfeld Nov 2016

Holocene Glacial Activity In Barilari Bay, West Antarctic Peninsula, Tracked By Magnetic Mineral Assemblages: Linking Ice, Ocean, And Atmosphere, Brendan Reilly, Carl Natter, Stefanie A. Brachfeld

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

We investigate the origin and fate of lithogenic sediments using magnetic mineral assemblages in Barilari Bay, west Antarctic Peninsula (AP) from sediment cores recovered during the Larsen Ice Shelf System, Antarctica (LARISSA) NBP10-01 cruise. To quantify and reconstruct Holocene changes in covarying magnetic mineral assemblages, we adopt an unsupervised mathematical unmixing strategy and apply it to measurements of magnetic susceptibility as a function of increasing temperature. Comparisons of the unmixed end-members with magnetic observations of northwestern AP bedrock and the spatial distribution of magnetic mineral assemblages within the fjord, allow us to identify source regions, including signatures for ‘‘inner bay,’’ …


Germination And Growth Of Native And Invasive Plants On Soil Associated With Biological Control Of Tamarisk (Tamarix Spp.), Rebecca A. Sherry, Patrick B. Shafroth, Jayne Belnap, Steven Ostoja, Sasha C. Reed Nov 2016

Germination And Growth Of Native And Invasive Plants On Soil Associated With Biological Control Of Tamarisk (Tamarix Spp.), Rebecca A. Sherry, Patrick B. Shafroth, Jayne Belnap, Steven Ostoja, Sasha C. Reed

United States Geological Survey: Staff Publications

Introductions of biocontrol beetles (tamarisk beetles) are causing dieback of exotic tamarisk in riparian zones across the western United States, yet factors that determine plant communities that follow tamarisk dieback are poorly understood. Tamarisk-dominated soils are generally higher in nutrients, organic matter, and salts than nearby soils, and these soil attributes might influence the trajectory of community change. To assess physical and chemical drivers of plant colonization after beetle-induced tamarisk dieback, we conducted separate germination and growth experiments using soil and litter collected beneath defoliated tamarisk trees. Focal species were two common native (red threeawn, sand dropseed) and two common …


Future Changes In Mean And Extreme Monsoon Precipitation In The Middle And Lower Yangtze River Basin, China, In The Cmip5 Models, Yanjuan Wu, Shuang-Ye Wu, Jiahong Wen, Felipe Tagle, Ming Xu, Jianguo Tan Nov 2016

Future Changes In Mean And Extreme Monsoon Precipitation In The Middle And Lower Yangtze River Basin, China, In The Cmip5 Models, Yanjuan Wu, Shuang-Ye Wu, Jiahong Wen, Felipe Tagle, Ming Xu, Jianguo Tan

Geology Faculty Publications

In this study, the potential future changes of mean and extreme precipitation in the middle and lower Yangtze River basin (MLYRB), eastern China, are assessed using the models of phase 5 of the Coupled Model Intercomparison Project (CMIP5). Historical model simulations are first compared with observations in order to evaluate model performance. In general, the models simulate the precipitation mean and frequency better than the precipitation intensity and extremes, but still have difficulty capturing precipitation patterns over complex terrains. They tend to overestimate precipitation mean, frequency, and intensity while underestimating the extremes. After correcting for model biases, the spatial variation …


Planetary-Scale Low-Level Circulation And The Unique Development Of Hurricane Wilma In 2005, Jinwoong Yoo, Robert V. Rohli, Jennifer Collins Nov 2016

Planetary-Scale Low-Level Circulation And The Unique Development Of Hurricane Wilma In 2005, Jinwoong Yoo, Robert V. Rohli, Jennifer Collins

School of Geosciences Faculty and Staff Publications

Large‐scale atmospheric and oceanic conditions in the western Atlantic basin were analyzed to understand the unique tropical cyclogenesis (TCG) and intensification mechanism of Hurricane Wilma in 2005, the most intense Atlantic basin tropical cyclone (TC) on record. An analysis of 850 hPa circulations depicted in the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis data suggests that anomalous development of the 850 hPa circulation pattern triggered by Hurricane Vince (October 8–11, 2005) contributed to the development of a large‐scale low‐level vortex that preceded Wilma's TCG in the eastern Caribbean. In particular, weakened easterly winds in the central …


Passive Rifting Of Thick Lithosphere In The Southern East African Rift: Evidence From Mantle Transition Zone Discontinuity Topography, Cory A. Reed, Kelly H. Liu, Patrick R. N. Chindandali, Belarmino Massingue, Hassan Mdala, Daniel Mutamina, Youqiang Yu, Stephen S. Gao Nov 2016

Passive Rifting Of Thick Lithosphere In The Southern East African Rift: Evidence From Mantle Transition Zone Discontinuity Topography, Cory A. Reed, Kelly H. Liu, Patrick R. N. Chindandali, Belarmino Massingue, Hassan Mdala, Daniel Mutamina, Youqiang Yu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To investigate the mechanisms for the initiation and early-stage evolution of the nonvolcanic southernmost segments of the East African Rift System (EARS), we installed and operated 35 broadband seismic stations across the Malawi and Luangwa rift zones over a 2 year period from mid-2012 to mid-2014. Stacking of over 1900 high-quality receiver functions provides the first regional-scale image of the 410 and 660 km seismic discontinuities bounding the mantle transition zone (MTZ) within the vicinity of the rift zones. When a 1-D standard Earth model is used for time-depth conversion, a normal MTZ thickness of 250 km is found beneath …


Mantle Structure Beneath The Incipient Okavango Rift Zone In Southern Africa, Youqiang Yu, Kelly H. Liu, Zhouchuan Huang, Dapeng Zhao, Cory A. Reed, Moikwathai Moidaki, Jianshe Lei, Stephen S. Gao Nov 2016

Mantle Structure Beneath The Incipient Okavango Rift Zone In Southern Africa, Youqiang Yu, Kelly H. Liu, Zhouchuan Huang, Dapeng Zhao, Cory A. Reed, Moikwathai Moidaki, Jianshe Lei, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Numerous investigations of the mature segments of the East African rift system (EARS) have significantly improved our understanding of the structure and processes associated with well-developed continental rifts. In contrast, knowledge of rifting processes at their early stage is still significantly limited. Here we present results from a teleseismic P-wave tomography investigation of the incipient Okavango rift zone (ORZ), which is located at the southwestern terminus of the EARS. P-wave relative travel-time residuals recorded by 17 recently deployed portable seismic stations were manually picked and inverted for three-dimensional upper-mantle and mantle transition-zone tomographic images beneath the ORZ and its adjacent …


The Purdue Agro-Climatic (Pac) Dataset For The U.S. Corn Belt: Development And Initial Results, Xing Liu, Elin Jacobs, Anil Kumar, Larry Biehl, Jeff Andersen, Dev Niyogi Oct 2016

The Purdue Agro-Climatic (Pac) Dataset For The U.S. Corn Belt: Development And Initial Results, Xing Liu, Elin Jacobs, Anil Kumar, Larry Biehl, Jeff Andersen, Dev Niyogi

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

This study is a result of a project titled ‘‘Useful to Usable (U2U): Transforming Climate Variability and Change Information for Cereal Crop Producers”. This paper responds to the project goal to improve farm resiliency and proftability in the U.S. Corn Belt region by transforming existing meteorological dataset into usable knowledge and tools for the agricultural community.

A high-resolution agro-climatic dataset that covers the U.S. Corn Belt was built for the U2U project based on a Land Data Assimilation System (LDAS) framework. This data referred to as the Purdue Agro-climatic (PAC) dataset is a gridded, continuous dataset suitable for agrocli- matic …


Exploring The Potential Linkages Between Oil-Field Brine Reinjection, Crystalline Basement Permeability, And Triggered Seismicity For The Dagger Draw Oil Field, Southeastern New Mexico, Usa, Using Hydrologic Modeling, Y. Zhang, Stanislav S. Edel, Jeff D. Pepin, Mark A. Person, Ronald F. Broadhead, J. P. Ortiz, Susan L. Bilek, Peter S. Mozley, James P. Evans Oct 2016

Exploring The Potential Linkages Between Oil-Field Brine Reinjection, Crystalline Basement Permeability, And Triggered Seismicity For The Dagger Draw Oil Field, Southeastern New Mexico, Usa, Using Hydrologic Modeling, Y. Zhang, Stanislav S. Edel, Jeff D. Pepin, Mark A. Person, Ronald F. Broadhead, J. P. Ortiz, Susan L. Bilek, Peter S. Mozley, James P. Evans

Geosciences Faculty Publications

We used hydrologic models to explore the potential linkages between oil-field brine reinjection and increases in earthquake frequency (up to Md 3.26) in southeastern New Mexico and to assess different injection management scenarios aimed at reducing the risk of triggered seismicity. Our analysis focuses on saline water reinjection into the basal Ellenburger Group beneath the Dagger Draw Oil field, Permian Basin. Increased seismic frequency (>Md 2) began in 2001, 5 years after peak injection, at an average depth of 11 km within the basement 15 km to the west of the reinjection wells. We considered several scenarios …


Mapping Robinia Pseudoacacia Forest Health Conditions By Using Combined Spectral, Spatial And Textureal Information Extracted From Ikonos Imagery, H. Wang, Ruiliang Pu, Z. Zhang Oct 2016

Mapping Robinia Pseudoacacia Forest Health Conditions By Using Combined Spectral, Spatial And Textureal Information Extracted From Ikonos Imagery, H. Wang, Ruiliang Pu, Z. Zhang

School of Geosciences Faculty and Staff Publications

n this study grey-level co-occurrence matrix (GLCM) textures and a local statistical analysis Getis statistic (Gi), computed from IKONOS multispectral (MS) imagery acquired from the Yellow River Delta in China, along with a random forest (RF) classifier, were used to discriminate Robina pseudoacacia tree health levels. The different RF classification results of the three forest health conditions were created: (1) an overall accuracy (OA) of 79.5% produced using the four MS band reflectances only; (2) an OA of 97.1% created with the eight GLCM features calculated from IKONOS Band 4 with the optimal window size of 13 × 13 and …


Slip Distribution Of The 2014 Mw=8.1 Pisagua, Northern Chile, Earthquake Sequence Estimated From Coseismic Fore-Arc Surface Cracks, John P. Loveless, Chelsea P. Scott, Richard W. Allmendinger, Gabriel González Oct 2016

Slip Distribution Of The 2014 Mw=8.1 Pisagua, Northern Chile, Earthquake Sequence Estimated From Coseismic Fore-Arc Surface Cracks, John P. Loveless, Chelsea P. Scott, Richard W. Allmendinger, Gabriel González

Geosciences: Faculty Publications

The 2014 Mw = 8.1 Iquique (Pisagua), Chile, earthquake sequence ruptured a segment of the Nazca-South America subduction zone that last hosted a great earthquake in 1877. The sequence opened >3700 surface cracks in the fore arc of decameter-scale length and millimeter-to centimeter-scale aperture. We use the strikes of measured cracks, inferred to be perpendicular to coseismically applied tension, to estimate the slip distribution of the main shock and largest aftershock. The slip estimates are compatible with those based on seismic, geodetic, and tsunami data, indicating that geologic observations can also place quantitative constraints on rupture properties. The earthquake sequence …


A New Image Processing Procedure Integrating Pci-Rpc And Arcgis-Spline Tools To Improve The Orthorectification Accuracy Of High-Resolution Satellite Imagery, Hongying Zhang, Ruiliang Pu, Xiuguo Liu Oct 2016

A New Image Processing Procedure Integrating Pci-Rpc And Arcgis-Spline Tools To Improve The Orthorectification Accuracy Of High-Resolution Satellite Imagery, Hongying Zhang, Ruiliang Pu, Xiuguo Liu

School of Geosciences Faculty and Staff Publications

Given the low accuracy of the traditional remote sensing image processing software when orthorectifying satellite images that cover mountainous areas, and in order to make a full use of mutually compatible and complementary characteristics of the remote sensing image processing software PCI-RPC (Rational Polynomial Coefficients) and ArcGIS-Spline, this study puts forward a new operational and effective image processing procedure to improve the accuracy of image orthorectification. The new procedure first processes raw image data into an orthorectified image using PCI with RPC model (PCI-RPC), and then the orthorectified image is further processed using ArcGIS with the Spline tool (ArcGIS-Spline). We …


A Complex Origin For The Kelso Dunes, Mojave National Preserve, California, Usa: A Case Study Using A Simple Geochemical Method With Global Applications, Daniel R. Muhs, Nicholas Lancaster, Gary L. Skipp Oct 2016

A Complex Origin For The Kelso Dunes, Mojave National Preserve, California, Usa: A Case Study Using A Simple Geochemical Method With Global Applications, Daniel R. Muhs, Nicholas Lancaster, Gary L. Skipp

United States Geological Survey: Staff Publications

The Kelso Dune field in southern California is intriguing because although it is of limited areal extent (~100 km2), it has a wide variety of dune forms and contains many active dunes (~40 km2), which is unusual in the Mojave Desert. Studies over the past eight decades have concluded that the dunes are derived primarily from a single source, Mojave River alluvium, under a dominant, westerly-to-northwesterly wind regime. The majority of these studies did not, however, present data to support the Mojave River as the only source.We conducted mineralogical and geochemical studies ofmost of the 14 geomorphically defined dune groups …


Interseismic Deformation And Moment Deficit Along The Manila Subduction Zone And The Philippine Fault System, Ya-Ju Hsu, Shui-Beih Yu, John P. Loveless, Teresito Bacolcol, Renato Solidum, Artemio Luis Jr., Alfie Pelicano, Jochen Woessner Oct 2016

Interseismic Deformation And Moment Deficit Along The Manila Subduction Zone And The Philippine Fault System, Ya-Ju Hsu, Shui-Beih Yu, John P. Loveless, Teresito Bacolcol, Renato Solidum, Artemio Luis Jr., Alfie Pelicano, Jochen Woessner

Geosciences: Faculty Publications

We examine interseismic coupling of the Manila subduction zone and fault activity in the Luzon area using a block model constrained by GPS data collected from 1998 to 2015. Estimated long-term slip rates along the Manila subduction zone show a gradual southward decrease from 90–100 mm/yr at the northwest tip of Luzon to 65–80 mm/yr at the southern portion of the Manila Trench. We provide two block models (models A and B) to illustrate possible realizations of coupling along the Manila Trench, which may be used to infer future earthquake rupture scenarios. Model A shows a low coupling ratio …


Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. Mckay, John Charles Priscu Oct 2016

Modeling The Thickness Of Perennial Ice Covers On Stratified Lakes Of The Taylor Valley, Antarctica, Maciej K. Obryk, Peter T. Doran, Jared A. Hicks, Christopher P. Mckay, John Charles Priscu

Geology Faculty Publications and Presentations

A 1-D ice cover model was developed to predict and constrain drivers of long-term ice thick-ness trends in chemically stratified lakes of Taylor Valley, Antarctica. The model is driven by surface ra-diative heat fluxes and heat fluxes from the underlying water column. The model successfully reproduced 16 a (between 1996 and 2012) of ice thickness changes for the west lobe of Lake Bonney (average ice thickness = 3.53 m) and Lake Fryxell (average ice thickness = 4.22 m). Long-term ice thick-ness trends require coupling with the thermal structure of the water column. The heat stored within the temperature maximum of …


Extinction Intensity, Selectivity And Their Combined Macroevolutionary Influence In The Fossil Record, Jonathan L. Payne, Andrew M. Bush, Ellen T. Chang, Noel A. Heim, Matthew L. Knope, Sara B. Pruss Oct 2016

Extinction Intensity, Selectivity And Their Combined Macroevolutionary Influence In The Fossil Record, Jonathan L. Payne, Andrew M. Bush, Ellen T. Chang, Noel A. Heim, Matthew L. Knope, Sara B. Pruss

Geosciences: Faculty Publications

The macroevolutionary effects of extinction derive from both intensity of taxonomic losses and selectivity of losses with respect to ecology, physiology and/or higher taxonomy. Increasingly, palaeontologists are using logistic regression to quantify extinction selectivity because the selectivity metric is independent of extinction intensity and multiple predictor variables can be assessed simultaneously. We illustrate the use of logistic regression with an analysis of physiological buffering capacity and extinction risk in the Phanerozoic marine fossil record. We propose the geometric mean of extinction intensity and selectivity as a metric for the influence of extinction events. The end-Permian mass extinction had the largest …


A Dual-Porosity-Stokes Model And Finite Element Method For Coupling Dual-Porosity Flow And Free Flow, Jiangyong Hou, Meilan Qiu, Xiaoming He, Chaohua Guo, Mingzhen Wei, Baojun Bai Oct 2016

A Dual-Porosity-Stokes Model And Finite Element Method For Coupling Dual-Porosity Flow And Free Flow, Jiangyong Hou, Meilan Qiu, Xiaoming He, Chaohua Guo, Mingzhen Wei, Baojun Bai

Mathematics and Statistics Faculty Research & Creative Works

In this paper, we propose and numerically solve a new model considering confined flow in dual-porosity media coupled with free flow in embedded macrofractures and conduits. Such situation arises, for example, for fluid flows in hydraulic fractured tight/shale oil/gas reservoirs. The flow in dual-porosity media, which consists of both matrix and microfractures, is described by a dual-porosity model. And the flow in the macrofractures and conduits is governed by the Stokes equation. Then the two models are coupled through four physically valid interface conditions on the interface between dual-porosity media and macrofractures/conduits, which play a key role in a physically …


In Situ Ion Exchange In A Micro-Porous Transition Metal Silicate Framework, Jason M. Lively Oct 2016

In Situ Ion Exchange In A Micro-Porous Transition Metal Silicate Framework, Jason M. Lively

Masters Theses & Specialist Projects

Ion selectivity of minerals has traditionally been utilized in industry as a catalyst, metal separation, and environmental reclamation/sequestration tool. There is an increased interest in understanding ion selectivity mechanisms of micro-porous minerals and mineral-like structures and how they can be applied in various industries: environmental and, potentially, pharmaceutical. This study seeks to understand the ion exchange mechanisms in micro-porous zirconosilicates using time-resolved Raman spectroscopy and X-ray diffraction. The thesis material was exchanged with H+, Na+, K+, and Cs+ in order to better understand structural changes as well as the influence of the H+-bonding during the exchange process. It is hypothesized …


Status Of Scientific Knowledge, Recovery Progress, And Future Research Directions For The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi Vladykov, 1955, K.J. Sulak, F. Parauka, W. T. Slack, R. T. Ruth, M. T. Randall, K. Luke, M. E. Price Sep 2016

Status Of Scientific Knowledge, Recovery Progress, And Future Research Directions For The Gulf Sturgeon, Acipenser Oxyrinchus Desotoi Vladykov, 1955, K.J. Sulak, F. Parauka, W. T. Slack, R. T. Ruth, M. T. Randall, K. Luke, M. E. Price

United States Geological Survey: Staff Publications

The Gulf Sturgeon, Acipenser oxyrinchus desotoi, is an anadromous species of Acipenseridae and native to North America. It currently inhabits and spawns in the upper reaches of seven natal rivers along the northern coast of the Gulf of Mexico from the Suwannee River, Florida, to the Pearl River, Louisiana, during spring to autumn. Next to the Alligator Gar (Atractosteus spatula), the Gulf Sturgeon is currently the largest fish species occurring in U.S. Gulf Coast rivers, attaining a length of 2.35 m and weights exceeding 135 kg, but historically attained a substantially larger size. Historically, the spawning populations existed in additional …


An Iterative Approach To Ground Penetrating Radar At The Maya Site Of Pacbitun, Belize, Sheldon Skaggs, Terry G. Powis, Clara R. Rucker, George Micheletti Sep 2016

An Iterative Approach To Ground Penetrating Radar At The Maya Site Of Pacbitun, Belize, Sheldon Skaggs, Terry G. Powis, Clara R. Rucker, George Micheletti

Publications and Research

Ground penetrating radar (GPR) surveys provide distinct advantages for archaeological prospection in ancient, complex, urban Maya sites, particularly where dense foliage or modern debris may preclude other remote sensing or geophysical techniques. Unidirectional GPR surveys using a 500 MHz shielded antenna were performed at the Middle Preclassic Maya site of Pacbitun, Belize. The survey in 2012 identified numerous linear and circular anomalies between 1 m and 2 m deep. Based on these anomalies, one 1 m × 4 m unit and three smaller units were excavated in 2013. These test units revealed a curved plaster surface not previously found at …


On The Importance Of Stratigraphic Control For Vertebrate Fossil Sites In Channel Islands National Park, California, Usa: Examples From New Mammuthus Finds On San Miguel Island, Jeffrey S. Pigati, Daniel R. Muhs, John P. Mcgeehin Sep 2016

On The Importance Of Stratigraphic Control For Vertebrate Fossil Sites In Channel Islands National Park, California, Usa: Examples From New Mammuthus Finds On San Miguel Island, Jeffrey S. Pigati, Daniel R. Muhs, John P. Mcgeehin

United States Geological Survey: Staff Publications

Quaternary vertebrate fossils, most notably mammoth remains, are relatively common on the northern Channel Islands of California. Well-preserved cranial, dental, and appendicular elements of Mammuthus exilis (pygmy mammoth) and Mammuthus columbi (Columbian mammoth) have been recovered from hundreds of localities on the islands during the past half-century or more. Despite this paleontological wealth, the geologic context of the fossils is described in the published literature only briefly or not at all, which has hampered the interpretation of associated 14C ages and reconstruction of past environmental conditions. We recently discovered a partial tusk, several large bones, and a tooth enamel plate …