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2021

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Articles 61 - 90 of 13583

Full-Text Articles in Geology

Mgrre_Pureoilscouttickets_Cartier, A. E. Sons Company_1_21127073070000, Mgrre Nov 2021

Mgrre_Pureoilscouttickets_Cartier, A. E. Sons Company_1_21127073070000, Mgrre

Legacy Scout Tickets from Pure Oil Company

No abstract provided.


Research Sites Get Closer To Field Camps Over Time: Informing Environmental Management Through A Geospatial Analysis Of Science In The Mcmurdo Dry Valleys, Antarctica, Stephen M. Chignell, Madeline E. Myers, Adrian Howkins, Andrew Fountain Nov 2021

Research Sites Get Closer To Field Camps Over Time: Informing Environmental Management Through A Geospatial Analysis Of Science In The Mcmurdo Dry Valleys, Antarctica, Stephen M. Chignell, Madeline E. Myers, Adrian Howkins, Andrew Fountain

Geology Faculty Publications and Presentations

As in many parts of the world, the management of environmental science research in Antarctica relies on cost-benefit analysis of negative environmental impact versus positive scientific gain. Several studies have examined the environmental impact of Antarctic field camps, but very little work looks at how the placement of these camps influences scientific research. In this study, we integrate bibliometrics, geospatial analysis, and historical research to understand the relationship between field camp placement and scientific production in the McMurdo Dry Valleys of East Antarctica. Our analysis of the scientific corpus from 1907–2016 shows that, on average, research sites have become less …


Mgrre_Pureoilscouttickets_White River Land Co Tract_1_21127059350000, Mgrre Nov 2021

Mgrre_Pureoilscouttickets_White River Land Co Tract_1_21127059350000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Fee_1_21127027830000, Mgrre Nov 2021

Mgrre_Pureoilscouttickets_Fee_1_21127027830000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Williams_1_21127026550000, Mgrre Nov 2021

Mgrre_Pureoilscouttickets_Williams_1_21127026550000, Mgrre

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No abstract provided.


The Sedimentary Geochemistry And Paleoenvironments Project, Úna C. Farrell, Rifaat Samawi, Savitha Anjanappa, Roman Klykov, Oyeleye O. Adeboye, Heda Agic, Anne Sofie C. Ahm, Thomas H. Boag, Fred Bowyer, Jochen J. Brocks, Tessa N. Brunoir, Donald E. Canfield, Xiaoyan Chen, Meng Cheng, Matthew O. Clarkson, Devon B. Cole, David R. Cordie, Peter W. Crockford, Huan Cui, Tais W. Dahl, Lucas D. Mouro, Keith Dewing, Stephen Q. Dornbos, Nadja Drabon, Julie A. Dumoulin, Joseph F. Emmings, Cecilia R. Endriga, Tiffani A. Fraser, Robert R. Gaines, Richard M. Gaschnig, Timothy M. Gibson, Geoffrey J. Gilleaudeau Nov 2021

The Sedimentary Geochemistry And Paleoenvironments Project, Úna C. Farrell, Rifaat Samawi, Savitha Anjanappa, Roman Klykov, Oyeleye O. Adeboye, Heda Agic, Anne Sofie C. Ahm, Thomas H. Boag, Fred Bowyer, Jochen J. Brocks, Tessa N. Brunoir, Donald E. Canfield, Xiaoyan Chen, Meng Cheng, Matthew O. Clarkson, Devon B. Cole, David R. Cordie, Peter W. Crockford, Huan Cui, Tais W. Dahl, Lucas D. Mouro, Keith Dewing, Stephen Q. Dornbos, Nadja Drabon, Julie A. Dumoulin, Joseph F. Emmings, Cecilia R. Endriga, Tiffani A. Fraser, Robert R. Gaines, Richard M. Gaschnig, Timothy M. Gibson, Geoffrey J. Gilleaudeau

Geosciences: Faculty Publications

No abstract provided.


A Global Set Of Subduction Zone Earthquake Scenarios And Recurrence Intervals Inferred From Geodetically Constrained Block Models Of Interseismic Coupling Distributions, Shannon E. Graham, John P. Loveless, Brendan J. Meade Nov 2021

A Global Set Of Subduction Zone Earthquake Scenarios And Recurrence Intervals Inferred From Geodetically Constrained Block Models Of Interseismic Coupling Distributions, Shannon E. Graham, John P. Loveless, Brendan J. Meade

Geosciences: Faculty Publications

The past 100 years have seen the occurrence of five (Formula presented.) earthquakes and 94 (Formula presented.) earthquakes. Here we assess the potential for future great earthquakes using inferences of interseismic subduction zone coupling from a global block model incorporating both tectonic plate motions and earthquake cycle effects. Interseismic earthquake cycle effects are represented using a first-order quasistatic elastic approximation and include (Formula presented.) of interacting fault system area across the globe. We use estimated spatial variations in decadal-duration coupling at 15 subduction zones and the Himalayan range front to estimate the locations and magnitudes of potential seismic events using …


Late Pleistocene And Early Holocene Sea-Level History And Glacial Retreat Interpreted From Shell-Bearing Marine Deposits Of Southeastern Alaska, Usa, James F. Baichtal, Alia J. Lesnek, Risa J. Carlson, Nicholas S. Schmuck, Jane L. Smith, Dennis J. Landwehr, Jason P. Briner Nov 2021

Late Pleistocene And Early Holocene Sea-Level History And Glacial Retreat Interpreted From Shell-Bearing Marine Deposits Of Southeastern Alaska, Usa, James F. Baichtal, Alia J. Lesnek, Risa J. Carlson, Nicholas S. Schmuck, Jane L. Smith, Dennis J. Landwehr, Jason P. Briner

Publications and Research

We leverage a data set of >720 shell-bearing marine deposits throughout southeastern Alaska (USA) to develop updated relative sea-level curves that span the past ~14,000 yr. This data set includes site location, elevation, description when avail-able, and 436 14C ages, 45 of which are published here for the first time. Our sea-level curves suggest a peripheral forebulge developed west of the retreating Cordilleran Ice Sheet (CIS) margin between ca. 17,000 and 10,800 calibrated yr B.P. By 14,870 ± 630 to 12,820 ± 340 cal. yr B.P., CIS mar-gins had retreated from all of southeastern Alaska’s fjords, channels, and passages. At …


Silica Sinter And The Evolution Of Hot Springs In The Alvord/Pueblo Valleys, Southeast Oregon, Usa, Leslie Allen Mowbray, Michael L. Cummings Nov 2021

Silica Sinter And The Evolution Of Hot Springs In The Alvord/Pueblo Valleys, Southeast Oregon, Usa, Leslie Allen Mowbray, Michael L. Cummings

Geology Faculty Publications and Presentations

Hot springs in the Alvord/Pueblo valleys in southeastern Oregon are analogous to Basinand- Range hydrothermal systems where heat source and permeable pathways are met through crustal thinning. Silica sinter deposition at Mickey Springs, Alvord Valley, predates the late Pleistocene high stand of pluvial Lake Alvord. At Borax Lake, Pueblo Valley, sinter deposition occurred during the Holocene. This study examines the evolution of springs at Mickey Springs, where three morphologies of sinter are present: (1) basalt clasts surrounded by sinter in interbedded conglomerate and sandstone, (2) pool-edge and aprons of sinter surrounding depressions (12–32 m diameter), and (3) quaquaversal sinter mounds …


Estimated Amounts And Rates Of Carbon Mobilized By Landsliding In Old-Growth Temperate Forests Of Se Alaska, Bryce A. Vascik, Adam M. Booth, Brian Buma, Matteo Berti Nov 2021

Estimated Amounts And Rates Of Carbon Mobilized By Landsliding In Old-Growth Temperate Forests Of Se Alaska, Bryce A. Vascik, Adam M. Booth, Brian Buma, Matteo Berti

Geology Faculty Publications and Presentations

Landslides, a forest disturbance, mobilize carbon (C) sequestered in vegetation and soils. Mobilized C is deposited either onto hillslopes or into the water, sequestering C from and releasing C to the atmosphere at different time scales. The C-dense old-growth temperate forests of SE Alaska are a unique location to quantify C mobilization rate by frequent landslides that often evolve into saturated moving masses known as debris flows. In this study, the amount of C mobilized by debris flows over historic time scales was estimated by combining a landslide inventory with maps of modeled biomass and soil carbon. We analyzed SE …


Apportioning Deformation Among Depth Intervals In An Aquifer System Using Insar And Head Data, Ryan G. Smith, Hossein Hashemi, Jingyi Chen, Rosemary Knight Nov 2021

Apportioning Deformation Among Depth Intervals In An Aquifer System Using Insar And Head Data, Ryan G. Smith, Hossein Hashemi, Jingyi Chen, Rosemary Knight

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Land surface subsidence due to excessive groundwater pumping is an increasing concern in California, USA. Interferometric Synthetic Aperture Radar (InSAR) is a remote sensing technique for measuring centimeter-to-millimeter surface deformation at 10-100 m spatial resolution. Here, a data-driven approach that attributes deformation to individual depth intervals within an aquifer system by integrating head data acquired from each of three screened intervals in a monitoring well with InSAR surface deformation measurements was developed. The study area was the Colusa Basin in northern Central Valley. To reconstruct the surface deformation history over the study area, 13 ALOS-PALSAR scenes acquired between 2006 and …


Mgrre_Pureoilscouttickets_Lewis_1_21127023980000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Lewis_1_21127023980000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Smith_2_21127023570000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Smith_2_21127023570000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Pinder._2_21127023530000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Pinder._2_21127023530000, Mgrre

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No abstract provided.


Three-Dimensional Intrusion Geometries In The Monogenetic San Rafael (Utah) Sub-Volcanic Field Revealed By Nonlinear Inversion Of Magnetic Anomaly Data, Troy A. Berkey Oct 2021

Three-Dimensional Intrusion Geometries In The Monogenetic San Rafael (Utah) Sub-Volcanic Field Revealed By Nonlinear Inversion Of Magnetic Anomaly Data, Troy A. Berkey

USF Tampa Graduate Theses and Dissertations

Distributed volcanic fields are common on Earth and nearby planetary bodies. Unlike their central-vent counterparts, these volcanic centers are comprised of many individual basaltic magmatic dikes, which are often only expressed at the surface in the form of vents, domes, and lava flows. In situ imaging of the shallow (<1 km) subsurface can reveal important details about the 3D geometry of fissure systems that feed distributed eruptive centers, with implications for the nature of these eruptions: their mass flow rates, explosivity, durations, and volcanotectonic interaction. Luckily, dikes, sills, conduits and related near-surface structures tend to carry high remnant magnetizations, creating magnetic anomalies at the surface where sufficient magnetic contrast exists with the host rocks they intrude. In the San Rafael Sub-volcanic field (SRSVF), basaltic dikes intrude fractured and horizontally bedded Jurassic sandstones, now eroded to a depth of about 800 m beneath the paleo-surface. Detailed mapping and profiles with a Cs-vapor magnetometer reveal far more complex anomalies than can be attributed to simple planar dikes, including: sills, buds, and domes. We image these geometries using MagCube-parallel, an open-source nonlinear inversion code we developed that models complex geometry with multiple (<= 1,000) vertical-sided prisms. I show one normally polarized fissure system to include along strike: An ~3-14 m thick, ~50 m wide dome-like feature or laccolith at depths of ~9-20 m, a roughly vertical conduit ~15 m thick, ~36-50 m wide, at ~1-16 m depth near the center of the mapped fissure-like system, and a ~8-48 m. wide dike at ~2-17 m depth that is <1-6 m thick, with reducing magnitude northward. While model depth and thickness vary with magnetization contrast, the main geometric relationships do not. Magnetic mapping of a nearby fissure reveals the same types of structures. The implication of these structures is that the small-volume fissure eruptions were likely pulsatory, with episodes of horizontal intrusion of sills, and sufficient time to develop gravitational instabilities.


Mgrre_Pureoilscouttickets_Crowfoot_1_21127022320000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Crowfoot_1_21127022320000, Mgrre

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No abstract provided.


Impacts Of Wood Fuel Uses On Forest Cover: The Case Of Semiarid Areas In Northern Tanzania, Debora J Mahushi, Revocatus L Machunda, Talam E Kibona Oct 2021

Impacts Of Wood Fuel Uses On Forest Cover: The Case Of Semiarid Areas In Northern Tanzania, Debora J Mahushi, Revocatus L Machunda, Talam E Kibona

Tanzania Journal of Science

Satellite images for the years 1987, 1997, 2002 and 2017, and questionnaire surveys were used to assess energy sources and demands as well as the impacts of wood fuel use to forest cover changes in Meru and Mwanga Districts. The major energy sources identified include cow dung cake, firewood, charcoal, liquefied petroleum gas and biogas. The total energy demands from these sources were 1400 (in Meru), 6289, 724 and 21 kg per day, respectively. The amount of biogas was not quantified since the reactors were constructed locally with no reading meter. Analysis from Landsat images showed variations in forest cover. …


The Importance Of Lithologic Variability And Stratigraphic Architecture In The Development Of Eogenetic Karst Systems, Nicholas J. Soto-Kerans Oct 2021

The Importance Of Lithologic Variability And Stratigraphic Architecture In The Development Of Eogenetic Karst Systems, Nicholas J. Soto-Kerans

USF Tampa Graduate Theses and Dissertations

Integrative characterizations of karst systems on low-lying eogenetic carbonate platforms are rare and often limited to areas of direct observation where caves can be entered and explored. Because hydraulic properties of eogenetic limestones have been implicitly assumed to be homogeneous, classical models of carbonate island karst development stressed the importance of geochemical interfaces in controlling cave and vug development. These studies have explained the largest cavern systems as results of either 1) mixing dissolution at platform margins or 2) microbially-mediated dissolution processes at water tables.

New data from core descriptions and wireline logs obtained in 18 boreholes drilled in the …


Mgrre_Pureoilscouttickets_Pinder_2_21127022210000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Pinder_2_21127022210000, Mgrre

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No abstract provided.


Effects Of Nitrate On Arsenic Mobilization During Aquifer Storage And Recovery, Hania Hawasli Oct 2021

Effects Of Nitrate On Arsenic Mobilization During Aquifer Storage And Recovery, Hania Hawasli

USF Tampa Graduate Theses and Dissertations

Aquifer storage and recovery technology is used to sustain water resources and to prevent saltwater intrusion. The injected water can come from various resources, including treated wastewater. In pilot ASR studies in the Tampa Bay region, researchers found high As concentrations in the recovered water from the oxidation of the arsenopyrite that is embedded in the aquifers. The presence of dissolved O2 in the injected water is a major factor in the arsenopyrite oxidation during ASR, however the effects of NO3- on the arsenopyrite has not been studied yet. This is an important knowledge gap because injected water may contain …


Slow Slip Events And The Earthquake Cycle, Nicholas K. Voss Oct 2021

Slow Slip Events And The Earthquake Cycle, Nicholas K. Voss

USF Tampa Graduate Theses and Dissertations

Slow Slip Events (SSEs) represent a new type of strain release along faults, which have onlybeen recognized as a global phenomena with the growth of precision space-borne geodetic techniques. These events represent an important part of the strain budget on faults, sometimes bounding the area of co-seismic release and perhaps limiting the amount of seismic energy release. SSEs have also been suggested to proceed large megathrust earthquakes including the great 2011 Tohoku and 2015 Iquique earthquakes. I document a series of SSE along the Nicoya Peninsula in Costa Rica. These events take place both before and after the 2012 M7.6 …


Mgrre_Pureoilscouttickets_Copenhaver_3_21127021450000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Copenhaver_3_21127021450000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Robertson_1_21127021230000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Robertson_1_21127021230000, Mgrre

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No abstract provided.


Assessing Morphological Response And Vulnerability Of Barrier Islands To Extreme Storms In Northwest Florida, Jacob Adam Oct 2021

Assessing Morphological Response And Vulnerability Of Barrier Islands To Extreme Storms In Northwest Florida, Jacob Adam

USF Tampa Graduate Theses and Dissertations

Barrier islands shield the mainland coast from the effects of extreme storms such as increased wave energy and storm surge. During these events, however, barrier morphology can be altered by erosive forces. Thus, compromising the protection offered and leading to increased impact on the mainland. The St. Joseph Peninsula, located in the Northwest of the Gulf of Mexico, is one such barrier at threat from storm-induced erosion. Presented here is an assessment of morphology change induced by two major storms to impact the peninsula, Hurricanes Dennis 2005 and Michael 2018. These changes characterize the erosive/depositional patterns that can be expected …


Mgrre_Pureoilscouttickets_Spitler_2_21127020990000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Spitler_2_21127020990000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Christman_1_21127020170000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Christman_1_21127020170000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Brinen_1_21127020080000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Brinen_1_21127020080000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Ackerman_1_21127019060000, Mgrre Oct 2021

Mgrre_Pureoilscouttickets_Ackerman_1_21127019060000, Mgrre

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No abstract provided.


Mgrre_Pureoilscouttickets_Smith_1_21127018950000, Mgrre Oct 2021

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No abstract provided.


Timescales Of Magma Transport In The Columbia River Flood Basalts, Determined By Paleomagnetic Data, Joseph Biasi, Leif Karlstrom Oct 2021

Timescales Of Magma Transport In The Columbia River Flood Basalts, Determined By Paleomagnetic Data, Joseph Biasi, Leif Karlstrom

Other Staff Materials

Flood basalts represent major events in Earth History, in part because they are linked to large climate perturbations and mass extinctions. However, the durations of individual flood basalt eruptions, which directly impact potential environmental crises, are poorly constrained. Here we use a combination of paleomagnetic data and thermal modeling to create a magnetic geothermometer (MGT) that can constrain the active transport lifetime of magmatic conduits and intrusions. We apply the MGT technique to eight feeder dike segments of the Columbia River basalts (CRB), demonstrating that some dike segments were actively heating host rocks for less than one month, while other …