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2021

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Articles 13321 - 13350 of 13583

Full-Text Articles in Geology

Mgrre_Thinsections_Moc_05_24, Mgrre Jul 2021

Mgrre_Thinsections_Moc_05_24, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Mgrre_12_165, Mgrre Jul 2021

Mgrre_Thinsections_Mgrre_12_165, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Mgrre_90_20, Mgrre Jul 2021

Mgrre_Thinsections_Mgrre_90_20, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Mgrre_39_24, Mgrre Jul 2021

Mgrre_Thinsections_Mgrre_39_24, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Moc_05_45, Mgrre Jul 2021

Mgrre_Thinsections_Moc_05_45, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_08-A_72, Mgrre Jul 2021

Mgrre_Thinsections_08-A_72, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Moc_10_75, Mgrre Jul 2021

Mgrre_Thinsections_Moc_10_75, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Moc_10_34, Mgrre Jul 2021

Mgrre_Thinsections_Moc_10_34, Mgrre

Thin Sections

No abstract provided.


Mgrre_Thinsections_Moc_10_46, Mgrre Jul 2021

Mgrre_Thinsections_Moc_10_46, Mgrre

Thin Sections

No abstract provided.


Factors Controlling Longshore Variations Of Beach Changes Induced By Tropical Storm Eta Along Pinellas County Beaches, West-Central Florida, Francesca Luisa Toledo Cossu Jul 2021

Factors Controlling Longshore Variations Of Beach Changes Induced By Tropical Storm Eta Along Pinellas County Beaches, West-Central Florida, Francesca Luisa Toledo Cossu

USF Tampa Graduate Theses and Dissertations

Tropical Storm Eta impacted the coast of west-central Florida from November 11 to 12, 2020, and generated high waves over elevated water levels for over 20 hours. A total of 148 beach and nearshore profiles, spaced about 300 m apart, were surveyed one to two weeks before and one to eight days after the storm to examine the beach changes along four barrier islands, including Sand Key, Treasure Island, Long Key and Mullet Key. Storm waves superimposed on elevated water levels reached the toe of dunes, causing modest dune erosion as well as overwash in some areas. Most of the …


Late Miocene Unroofing Of The Inner Lesser Himalaya Recorded In The Nw Himalaya Foreland Basin, Elise Marie Exnicios Jul 2021

Late Miocene Unroofing Of The Inner Lesser Himalaya Recorded In The Nw Himalaya Foreland Basin, Elise Marie Exnicios

LSU Master's Theses

Testing models that link climate and solid Earth tectonics requires independent erosional, structural and climatic histories. Two well preserved stratigraphic sections of the Himalayan foreland basin are exposed in NW India. The Jawalamukhi (13–5 Ma) and Joginder Nagar sections (21–13 Ma) are dated by magnetostratigraphy and span a period of significant climate change and tectonic evolution. We use detrital zircon U-Pb dating and apatite fission track analyses to reconstruct changes in the patterns of erosion and exhumation in this area from the Early Miocene to Pliocene. The provenance of the foreland sediments shows that since at least ~21 Ma the …


New Perspectives On Prolific And Voluminous Rhyolite Volcanism Of The Mahogany Mountain--Three Fingers Rhyolite Field, Eastern Oregon, Robert Andrew Jackson Jul 2021

New Perspectives On Prolific And Voluminous Rhyolite Volcanism Of The Mahogany Mountain--Three Fingers Rhyolite Field, Eastern Oregon, Robert Andrew Jackson

Dissertations and Theses

Voluminous silicic volcanism of the Mahogany Mountain--Three Fingers rhyolite field (MM--TFrf) is spatially and temporally associated with mid-Miocene flood basalts of the Columbia River Basalt province. Early studies of the area advocated for a two-caldera model consisting of the Mahogany Mountain and the slightly younger Three Fingers caldera with pre- and post-caldera effusive rhyolite eruptions. Although close in time, the calderas were thought to be spatially offset producing the tuff of Leslie Gulch and the tuff of Spring Creek. Finding that the tuff of Spring Creek, that is exposed in Leslie Gulch, is an altered product of the tuff of …


Petrology And Geochemistry Of Evolved Achondrites: Planetesimal Mantles And Crusts, Zoltan Vaci Jul 2021

Petrology And Geochemistry Of Evolved Achondrites: Planetesimal Mantles And Crusts, Zoltan Vaci

Earth and Planetary Sciences ETDs

Melting and differentiation are fundamental to early solar system evolution on planetary bodies that accreted enough material to heat up radioactively or through impacts and breach their solidi. Partially and fully melted material is present in the meteorite record in the form of primitive achondrites and achondrites, which are fragments of planetesimals that underwent heating events in the first few million years of solar system history. Although the vast majority of this material is mafic or ultramafic, new evolved samples, recovered in the last few decades, are pushing the petrologic and geochemical boundaries of planetesimal melting, differentiation, and crust formation. …


Managing For Radical Ecosystem Change: Applying The Resist-Accept-Direct (Rad) Framework, Abigail J. Lynch, Laura M. Thompson, Erik A. Beever, David N. Cole, Augustin C. Engman, Cat Hawkins Hoffman, Stephen T. Jackson, Trevor J. Krabbenhoft, David J. Lawrence, Douglas Limpinsel, Robert T. Magill, Tracy A. Melvin, John M. Morton, Robert Newman, Jay O. Peterson, Mark T. Porath, Frank J. Rahel, Gregor W. Schuurman, Suresh A. Sethi, Jennifer L. Wilkening Jul 2021

Managing For Radical Ecosystem Change: Applying The Resist-Accept-Direct (Rad) Framework, Abigail J. Lynch, Laura M. Thompson, Erik A. Beever, David N. Cole, Augustin C. Engman, Cat Hawkins Hoffman, Stephen T. Jackson, Trevor J. Krabbenhoft, David J. Lawrence, Douglas Limpinsel, Robert T. Magill, Tracy A. Melvin, John M. Morton, Robert Newman, Jay O. Peterson, Mark T. Porath, Frank J. Rahel, Gregor W. Schuurman, Suresh A. Sethi, Jennifer L. Wilkening

Biology Faculty Publications

Ecosystem transformation involves the emergence of persistent ecological or social–ecological systems that diverge, dramatically and irreversibly, from prior ecosystem structure and function. Such transformations are occurring at increasing rates across the planet in response to changes in climate, land use, and other factors. Consequently, a dynamic view of ecosystem processes that accommodates rapid, irreversible change will be critical for effectively conserving fish, wildlife, and other natural resources, and maintaining ecosystem services. However, managing ecosystems toward states with novel structure and function is an inherently unpredictable and difficult task. Managers navigating ecosystem transformation can benefit from considering broader objectives, beyond a …


Geologist Syed Humayun Akhter Is Leading The Bangladesh Open University, Nazrul I. Khandaker Jul 2021

Geologist Syed Humayun Akhter Is Leading The Bangladesh Open University, Nazrul I. Khandaker

Publications and Research

No abstract provided.


Quaternary Geology Of Portions Of The Mcgregor Peak, Murr Peak, Marion, And Hubbart Reservoir, 7.5’ Quadrangles, Flathead County, Montana, Carlos Montejo Jul 2021

Quaternary Geology Of Portions Of The Mcgregor Peak, Murr Peak, Marion, And Hubbart Reservoir, 7.5’ Quadrangles, Flathead County, Montana, Carlos Montejo

Graduate Theses & Non-Theses

Quaternary deposits in the northern Little Bitterroot River watershed record the advance and retreat of the Cordilleran Ice Sheet, transgression of Glacial Lake Missoula, and at least one partial or complete drainage of Glacial Lake Missoula during the last Pleistocene glaciation. New geologic mapping at a scale of 1:24,000 in portions of the McGregor Peak, Marion, Murr Peak, and Hubbart Reservoir quadrangles with a focus on Quaternary deposits has refined boundaries for where the Cordilleran Ice Sheet and Glacial Lake Missoula coincided. Stratigraphic analysis of three measured sections within Glacial Lake Missoula sediments along with three optically stimulated luminescence ages …


An Early Triassic Small Shelly Fossil-Style Assemblage From The Virgin Limestone Member, Moenkopi Formation, Western United States, Vivienne Maxwell, Ben Thuy, Sara B. Pruss Jul 2021

An Early Triassic Small Shelly Fossil-Style Assemblage From The Virgin Limestone Member, Moenkopi Formation, Western United States, Vivienne Maxwell, Ben Thuy, Sara B. Pruss

Geosciences: Faculty Publications

Small shelly fossils (SSFs) are minute fossils moulded or replaced by apatite, and less commonly, other minerals like glauconite and iron oxides. This taphonomic mode is best known from Cambrian deposits, though some occurrences occur across geological time. Instances of small shelly-style preservation were found in insoluble residues from the Lower Triassic Virgin Limestone Member exposed in southern Nevada, the western United States, a second such occurrence known from this unit. Fossil steinkerns of tiny brachiopods, echinoid spines and ophiuroids are fluorapatite, with scarce phosphatic internal moulds of bivalves and two replaced ostracods. In contrast, the crinoid ossicles, almost all …


Fractured Rock Groundwater Wa Wheatbelt: Data And Methodology Review, Louise Hopgood, Richard Nixon Jul 2021

Fractured Rock Groundwater Wa Wheatbelt: Data And Methodology Review, Louise Hopgood, Richard Nixon

Natural resources commissioned reports

The Department of Primary Industries and Regional Development (DPIRD) in partnership with Water Corporation, working with Murdoch and Curtin universities, are looking at new options to improve farm water security in the wheatbelt of Western Australia.

Winter rainfall has declined since 2000 and dams, traditionally used for farm water supply, no longer provide sufficient or reliable water, especially after 1 to 2 below average years. Increasingly, groundwater supplies are being considered to supply farm needs, including those from fractured rock aquifers, with opportunities to desalinate to improve water quality.

This project undertook to review groundwater availability in fractured rock aquifers …


Cellular Remains In A ~3.42-Billion-Year-Old Subseafloor Hydrothermal Environment, Barbara Cavalazzi, Laurence Lamelle, Alexandre Simionovici, Sherry L. Cady, Michael J. Russell, Elena Bailo, Roberto Canteri, Emanuele Enrico, Alain Manceau, Multiple Additional Authors Jul 2021

Cellular Remains In A ~3.42-Billion-Year-Old Subseafloor Hydrothermal Environment, Barbara Cavalazzi, Laurence Lamelle, Alexandre Simionovici, Sherry L. Cady, Michael J. Russell, Elena Bailo, Roberto Canteri, Emanuele Enrico, Alain Manceau, Multiple Additional Authors

Geology Faculty Publications and Presentations

Subsurface habitats on Earth host an extensive extant biosphere and likely provided one of Earth’s earliest microbial habitats. Although the site of life’s emergence continues to be debated, evidence of early life provides insights into its early evolution and metabolic affinity. Here, we present the discovery of exceptionally well-preserved, ~3.42-billion-year-old putative filamentous microfossils that inhabited a paleo-subseafloor hydrothermal vein system of the Barberton greenstone belt in South Africa. The filaments colonized the walls of conduits created by low-temperature hydrothermal fluid. Combined with their morphological and chemical characteristics as investigated over a range of scales, they can be considered the oldest …


Carbon Storage Via Mineral Bonding In Subsoils A Review Of Soil Processes, Kiele Goins Jul 2021

Carbon Storage Via Mineral Bonding In Subsoils A Review Of Soil Processes, Kiele Goins

Theses and Dissertations

Soil is an important but often poorly understood portion of the carbon cycle. Soil can store more carbon than twice today’s atmosphere, but the factors that control carbon storage are often unclear. Carbon enters the soil through input of organic matter, erosion, and aerosol deposition and is lost mostly via microbial decomposition. Carbon loss in soil is impacted by the chemical composition of organic compounds, environmental factors, and human activities. Furthermore, as climate changes soil, carbon storage may be vulnerable. Although carbon can be stored throughout soil, carbon storage varies with depth. In topsoil, carbon is stored for short periods …


Modeling The Lafourche Delta Network In The Mississippi Delta Complex, Byong-Suk Chun Jul 2021

Modeling The Lafourche Delta Network In The Mississippi Delta Complex, Byong-Suk Chun

Graduate Theses and Dissertations

The distributary channel network morphology on deltas is important for the delta evolution study because channels are the primary conduit for carrying and distributing water, sediment, and nutrients to the coast. Numerical models of river deltas and their channels have improved remarkably over the past two decades. However, the long-term (millennial scale) simulation of real delta systems remains rare. Here, we attempt to reconstruct the Lafourche Delta channel network, active 1600-600 years before present, with a simple numerical model (Moving Boundary Model for Distributary Network, MB_DCN). The model was run for 9 possible paleo basin boundaries and 6 water discharge …


Groundwater Flow And Transport At The Forest-Marsh Boundary: A Modeling Study, Sophia Chason Sanders Jul 2021

Groundwater Flow And Transport At The Forest-Marsh Boundary: A Modeling Study, Sophia Chason Sanders

Theses and Dissertations

The forest-marsh boundary, where tidally influenced salt marshes meet a forested upland, is hydrologically complex due to its multiple water inputs. Groundwater flow and salinity transport at this boundary are not well understood. In order to make predictions about salinity at this boundary as it responds to climatic factors, a two-dimensional model was built to simulate groundwater flow and solute transport at a salt marsh on Sapelo Island, Georgia. After calibration based on observed data from wells at the study site, the model can be used to identify patterns in groundwater movement and solute transport that may influence the vegetation …


Groundwater Discharge From Passive Continental Margins: Rethinking Marine Chemical Budgets, Andrew William Osborne Jul 2021

Groundwater Discharge From Passive Continental Margins: Rethinking Marine Chemical Budgets, Andrew William Osborne

Theses and Dissertations

Geothermal convection and sediment compaction drive large-scale flow in continental shelves. We suggest that this flow is an overlooked control on the major ion chemistry of the ocean. Conventional ocean chemical budgets are constructed using river discharge, axial mid-ocean ridge (MOR) convection and CaCO3 production, but these budgets are still poorly quantified. We synthesized data from 17 passive continental margin basins to calculate a range of estimated groundwater and chemical fluxes from continental shelves, considering five major ions (Ca2+, Na+, K+, Mg2+, and Cl-). When extrapolated globally, volumetric groundwater flux estimates were comparable to those for MOR axial circulation, and …


Collaborative Research: A Fossil Ecosystem Under The Ice: Deciphering The Glacial And Vegetation History Of Nothwest Greenland Using Long Lost Camp Century Basal Sediment, Tammy M. Rittenour Jul 2021

Collaborative Research: A Fossil Ecosystem Under The Ice: Deciphering The Glacial And Vegetation History Of Nothwest Greenland Using Long Lost Camp Century Basal Sediment, Tammy M. Rittenour

Funded Research Records

No abstract provided.


Slip And Strain Accumulation Along The Sadie Creek Fault, Olympic Peninsula, Washington, W. Cody Duckworth, Colin B. Amos, Elizabeth R. Schermer, John P. Loveless, Tammy M. Rittenour Jun 2021

Slip And Strain Accumulation Along The Sadie Creek Fault, Olympic Peninsula, Washington, W. Cody Duckworth, Colin B. Amos, Elizabeth R. Schermer, John P. Loveless, Tammy M. Rittenour

Geosciences: Faculty Publications

Upper-plate faulting in the Olympic Peninsula of Washington State results from relative motion of crustal blocks within the Cascadia forearc and earthquake cycle processes along the Cascadia subduction zone. We reconstruct fault slip rates since ∼14 ka on the Sadie Creek fault (SCF), north of the Olympic Mountains, using airborne lidar and field mapping of surficial deposits and landforms and optically stimulated luminescence and radiocarbon dating. The SCF is a ≥14 km-long northwest-striking, subvertical, dextral strike-slip fault with a subordinate dip-slip component. Laterally, offset debris flow channels cut into Late-Pleistocene and younger surfaces show dextral slip of 4.0–24.5 m and …


Geological And Geochemical Analysis Of Phosphorus Bearing Minerals And Natural Glasses On Earth And In Meteorites: Implications Of The Origin Of Life, Tian Feng Jun 2021

Geological And Geochemical Analysis Of Phosphorus Bearing Minerals And Natural Glasses On Earth And In Meteorites: Implications Of The Origin Of Life, Tian Feng

USF Tampa Graduate Theses and Dissertations

Phosphorus is a key element in biogenic molecules and the mineral schreibersite is a major reactive phosphorus source for organic compounds on the prebiotic Earth. In this dissertation, a suite of reactions of phosphorus species, which originate from schreibersite minerals on chondrite meteorites and on the early Earth, have been studied to determine the intermediate geochemical pathways between phosphides and common minerals on meteorites and on the early earth.

I first investigated a unique blue fulgurite that was studied to clarify if this blue color was caused by rich phosphorus content, as has been reported for impact glasses that also …


A Global Dataset Of Atmospheric 7be And 210pb Measurements: Annual Air Concentration And Depositional Flux, Fule Zhang, Jinlong Wang, Mark Baskaran, Qiangqiang Zhong, Yali Wang, Jussi Paatero, Jinzhou Du Jun 2021

A Global Dataset Of Atmospheric 7be And 210pb Measurements: Annual Air Concentration And Depositional Flux, Fule Zhang, Jinlong Wang, Mark Baskaran, Qiangqiang Zhong, Yali Wang, Jussi Paatero, Jinzhou Du

Environmental Science and Geology Faculty Research Publications

7Be and 210Pb air concentration and depositional flux data provide key information on the origins and movements of air masses, as well as atmospheric deposition processes and residence time of aerosols. After their deposition onto the Earth's surface, they are utilized for tracing soil redistribution processes on land, particle dynamics in aquatic systems, and mixing processes in open ocean. Here we present a global dataset of air concentration and depositional flux measurements of atmospheric 7Be and 210Pb made by a large number of global research communities. Data were collected from published papers between 1955 and early 2020. It includes the …


239-30k, Scott Brande Jun 2021

239-30k, Scott Brande

RockDoc - 3D Rock Models

Model created by Dr. Scott Brande

Rock formed May 2021 during eruption of mantle-sourced magma from Fagradalsfjall volcano in the valley of Geldingadalir, Iceland. Many thanks to Ben Smith and Danny Smith for collecting the sample under the fall of hot debris. Sample size about 6 cm.


An Actionable Anti-Racism Plan For Geoscience Organizations, Hendratta N. Ali Ph.D., Sarah L. Sheffield, Jennifer E. Bauer, Rocío P. Caballero-Gill, Nicole M. Gasparini, Julie Libarkin, Kalynda K. Gonzales, Jane Willenbring, Erika Amir-Lin, Julia Cisneros, Dipa Desai, Maitri Erwin, Elisabeth Gallant, Kiara Jeannelle Gomez, Benjamin A. Keisling, Robert Mahon, Erika Marín-Spiotta, Leiaka Welcome, Blair Schneider Jun 2021

An Actionable Anti-Racism Plan For Geoscience Organizations, Hendratta N. Ali Ph.D., Sarah L. Sheffield, Jennifer E. Bauer, Rocío P. Caballero-Gill, Nicole M. Gasparini, Julie Libarkin, Kalynda K. Gonzales, Jane Willenbring, Erika Amir-Lin, Julia Cisneros, Dipa Desai, Maitri Erwin, Elisabeth Gallant, Kiara Jeannelle Gomez, Benjamin A. Keisling, Robert Mahon, Erika Marín-Spiotta, Leiaka Welcome, Blair Schneider

Geosciences Faculty Publications

Geoscience organizations shape the discipline. They influence attitudes and expectations, set standards, and provide benefits to their members. Today, racism and discrimination limit the participation of, and promote hostility towards, members of minoritized groups within these critical geoscience spaces. This is particularly harmful for Black, Indigenous, and other people of color in geoscience and is further exacerbated along other axes of marginalization, including disability status and gender identity. Here we present a twenty-point anti-racism plan that organizations can implement to build an inclusive, equitable and accessible geoscience community. Enacting it will combat racism, discrimination, and the harassment of all members.


Field And Remote Sensing Analysis Of The 2015 Pyroclastic Density Currents At Colima (Mexico) And Calbuco (Chile) Volcanoes: Implications For Hazard Assessment And Crisis Management, Elodie Macorps Jun 2021

Field And Remote Sensing Analysis Of The 2015 Pyroclastic Density Currents At Colima (Mexico) And Calbuco (Chile) Volcanoes: Implications For Hazard Assessment And Crisis Management, Elodie Macorps

USF Tampa Graduate Theses and Dissertations

Although one of the most spectacular phenomena of active volcanoes, Pyroclastic density currents, or PDCs, are considered the most dangerous volcanic hazards. PDCs are avalanches of hot volcanic gases, ash, and larger volcanic fragments that travel at incredible speed down the flank of a volcano. High dynamic pressures, high temperatures, and high velocities are the primary dangers associated with PDCs and lead to near-complete destruction and death.

I use a multi-disciplinary approach to study the deposits left behind by PDCs, in order to understand their dynamics, their interactions with the receiving landscape, and their final distribution, starting on the ground …