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2021

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Articles 15871 - 15900 of 16206

Full-Text Articles in Earth Sciences

New Hampshire Continental Shelf Geophysical Database: 2002-2005 Jeffreys Ledge Field Campaign – Seafloor Photographs And Sediment Data, Larry G. Ward, Raymond E. Grizzle, Rachel C. Morrison Jan 2021

New Hampshire Continental Shelf Geophysical Database: 2002-2005 Jeffreys Ledge Field Campaign – Seafloor Photographs And Sediment Data, Larry G. Ward, Raymond E. Grizzle, Rachel C. Morrison

Data Catalog

Jeffreys Ledge is a major physiographic feature in the western Gulf of Maine (WGOM) located ~50 km off the coast of New Hampshire, although coming within ~10 km of shore by Cape Ann, Massachusetts. Jeffreys Ledge rises up as much as ~150 m from the seafloor of the adjacent basins (i.e., Scantum Basin or Wilkinson Basin) to depths less than 50 m on the ridge surface. The ridge extends over 100 km along its north-northeast to south-southwest axes while generally only being 5 to 10 km in width (~20 km maximum). Jeffreys Ledge and the surrounding region, like many features …


Computational Modeling For Decision-Making Under Climate Change Uncertainty: Reservoir Simulation Game, Julianne Quinn Jan 2021

Computational Modeling For Decision-Making Under Climate Change Uncertainty: Reservoir Simulation Game, Julianne Quinn

All ECSTATIC Materials

Almost every decision you make is under uncertainty. Will I need a rain jacket in the afternoon? Will they say yes if I ask them out? Is 1 hour enough time to finish this assignment? Oftentimes, we can use computational modeling to simulate different scenarios of what might happen in the future to inform what decisions are best on average, or what decisions minimize the worst case outcome. For example, you could decide what player to draft for your Fantasy Football team by simulating player performance. In this activity, we will simulate how much water to release from a dam …


Bed Particle Displacements And Morphological Development In A Wandering Gravel-Bed River, Ryan Mcqueen, Peter Ashmore, T Millard, N Goeller Jan 2021

Bed Particle Displacements And Morphological Development In A Wandering Gravel-Bed River, Ryan Mcqueen, Peter Ashmore, T Millard, N Goeller

Geography & Environment Publications

Bed particles were tracked using passive integrated transponder tags in a wandering reach of the San Juan River, British Columbia, Canada, to assess particle movement around three major bars in the river. In-channel topographic changes were monitored through repeat LiDAR surveys during this period and used in concert with the tracer data set to assess the relationship between particle displacements and changes in channel morphology, specifically, the development and re-working of bars. This has direct implications for virtual velocity and morphologic based estimates of bedload flux, which rely on accurate estimates of the variability and magnitude of particle path lengths …


Spectral Properties Of Lunar Impact Melt Deposits From Moon Mineralogy Mapper (M3) Data, Catherine Neish, Kevin Cannon, Livio Tornabene, Roberta Flemming, Michael Zanetti, Eric Pilles Jan 2021

Spectral Properties Of Lunar Impact Melt Deposits From Moon Mineralogy Mapper (M3) Data, Catherine Neish, Kevin Cannon, Livio Tornabene, Roberta Flemming, Michael Zanetti, Eric Pilles

Earth Sciences Publications

Lunar impact melt deposits have unusual surface properties, unlike any measured terrestrial lava flow. Radar observations suggest that they are incredibly rough at decimeter scales, but they appear smooth in high-resolution, meter-scale optical images. The cause of their unusual surface roughness is unknown. In this work, we investigate the properties of impact melt deposits from seven lunar craters, ranging in size from 7.5 to 96 km in diameter, in an effort to understand the cause of their unique surface texture. We use data from the Lunar Reconnaissance Orbiter’s (LRO) Mini-RF instrument to characterize the small-scale roughness of the deposits, data …


Designing Computer Applications To Model Geophysical Data For Siting Wells In Developing Countries, Aj Vrieland, Victor T. Norman Jan 2021

Designing Computer Applications To Model Geophysical Data For Siting Wells In Developing Countries, Aj Vrieland, Victor T. Norman

Summer Research

In some parts of the world, clean water is hard to find, and wells can be one of the best options available. However, creating a well is a big investment, so finding the best place to site the well is important. Commercial well siting software is prohibitively expensive for many development organizations, costing tens of thousands of dollars. Our open-source software duplicates some functionality of commercial software, but with none of the expense. This summer our project focused on software implementing two geophysical models, resistivity and seismic refraction.


Bathymetry Based Modeling Of Subaxial Magma Flows Under The Mid-Atlantic Ridge, 0 To 30° N, Adam R. Tjoelker, Neil Van Kanegan, C. Renee Sparks Jan 2021

Bathymetry Based Modeling Of Subaxial Magma Flows Under The Mid-Atlantic Ridge, 0 To 30° N, Adam R. Tjoelker, Neil Van Kanegan, C. Renee Sparks

Summer Research

The study area for this investigation includes the MidAtlantic Ridge (MAR) system from the Equator to 30° north latitude. In its entirety, the MAR system runs from around 87° N to 54° S through roughly the center of the Atlantic Ocean. The width of the Ridge ranges from 1000-1300 km (Liu et al., 2021). After conducting a similar study of the MAR system from the Equator to 30° S latitude, (Detmer et al., 2021 in review), the addition of magmatic modelling in this study enables continued investigation of the MAR’s tectonic fabric and allows us to test our hypotheses for …


A Novel Strategy To Reconstruct Ndvi Time-Series With High Temporal Resolution From Modis Multi-Temporal Composite Products, Linglin Zeng, Brian Wardlow, Shun Hu, Xiang Zhang, Guoqing Zhou, Guozhang Peng, Daxiang Xiang, Rui Wang, Ran Meng, Weixiong Wu Jan 2021

A Novel Strategy To Reconstruct Ndvi Time-Series With High Temporal Resolution From Modis Multi-Temporal Composite Products, Linglin Zeng, Brian Wardlow, Shun Hu, Xiang Zhang, Guoqing Zhou, Guozhang Peng, Daxiang Xiang, Rui Wang, Ran Meng, Weixiong Wu

Center for Advanced Land Management Information Technologies: Publications

Vegetation indices (VIs) data derived from satellite imageries play a vital role in land surface vegetation and dynamic monitoring. Due to the excessive noises (e.g., cloud cover, atmospheric contamination) in daily VI data, temporal compositing methods are commonly used to produce composite data to minimize the negative influence of noise over a given compositing time interval. However, VI time series with high temporal resolution were preferred by many applications such as vegetation phenology and land change detections. This study presents a novel strategy named DAVIR-MUTCOP (DAily Vegetation Index Reconstruction based on MUlti-Temporal COmposite Products) method for normalized difference vegetation index …


Long-Term African Dust Delivery To The Eastern Atlantic Ocean From The Sahara And Sahel Regions: Evidence From Quaternary Paleosols On The Canary Islands, Spain, Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Kathleen R. Simmons, Matthew C. Baddock, Juan F. Betancourt, Alejandro Lomoschitz Jan 2021

Long-Term African Dust Delivery To The Eastern Atlantic Ocean From The Sahara And Sahel Regions: Evidence From Quaternary Paleosols On The Canary Islands, Spain, Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Kathleen R. Simmons, Matthew C. Baddock, Juan F. Betancourt, Alejandro Lomoschitz

United States Geological Survey: Staff Publications

Africa is the most important source of dust in the world today and dust storms from that continent frequently deposit sediment on the nearby Canary Islands. Many investigators have inferred African dust inputs to Canary Islands paleosols based only on the presence of quartz. However, some local rocks do contain this mineral, so quartz alone is insufficient proof of dust deposition. Further, it is not known whether the Sahara Desert or the Sahel region is more important as a dust source. We address these issues by study of sequences of Pleistocene aeolian sands on the islands of Lanzarote and Fuerteventura. …


Eolian Sediments, Daniel R. Muhs Jan 2021

Eolian Sediments, Daniel R. Muhs

United States Geological Survey: Staff Publications

Eolian (windblown) sediments form some of the world’s most dramatic landscapes and comprise important parts of the geologic record. This article reviews the characteristics, origins, and significance of eolian deposits, including windblown sand, silt, and dust.

Landforms composed of eolian sand, either as dunes or sand sheets, occupy substantial areas over the surface of the Earth (perhaps as much as 6% globally, but over ~20% of the world’s arid zones, according to Pye and Tsoar, 2009). Low-latitude arid or semiarid regions, usually under the influence of subtropical high-pressure cells, are some of the largest areas of eolian sand accumulation (Lancaster, …


Ecology Of An Isolated Muskrat Population During Regional Population Declines, Laken S. Ganoe, Matthew J. Lovallo, Justin D. Brown, W. David Walter Jan 2021

Ecology Of An Isolated Muskrat Population During Regional Population Declines, Laken S. Ganoe, Matthew J. Lovallo, Justin D. Brown, W. David Walter

United States Geological Survey: Staff Publications

Evidence indicating a decline in Ondatra zibethicus (Muskrat) populations in the United States during the past 40 years has led to speculation regarding factors influencing Muskrat survival. In order to understand population dynamics and survival, it is important to first define the ecology of local populations. We investigated the dwelling structure use, movements, home range, and survival of radio-tagged Muskrats (n = 14) in an urban wetland complex in central Pennsylvania. We used locations collected from intensive radio-telemetry monitoring to determine number of lodging structures used, hourly movement, and size and percent area overlap of home ranges. Muskrats shared …


Elemental And Radionuclide Exposures And Uptakes By Small Rodents, Invertebrates, And Vegetation At Active And Post-Production Uranium Mines In The Grand Canyon Watershed, Danielle Cleveland, Jo Ellen Hinck, Julia S. Lankton Jan 2021

Elemental And Radionuclide Exposures And Uptakes By Small Rodents, Invertebrates, And Vegetation At Active And Post-Production Uranium Mines In The Grand Canyon Watershed, Danielle Cleveland, Jo Ellen Hinck, Julia S. Lankton

United States Geological Survey: Staff Publications

The effects of breccia pipe uranium mining in the Grand Canyon watershed (Arizona) on ecological and cultural resources are largely unknown. We characterized the exposure of biota to uranium and cooccurring ore body elements during active ore production and at a site where ore production had recently concluded. Our results indicate that biota have taken up uranium and other elements (e.g., arsenic, cadmium, copper, molybdenum, uranium) from exposure to ore and surficial contamination, like blowing dust. Results indicate the potential for prolonged exposure to elements and radionuclides upon conclusion of active ore production. Mean radium-226 in deer mice was up …


Soils And Paleosols, Daniel R. Muhs Jan 2021

Soils And Paleosols, Daniel R. Muhs

United States Geological Survey: Publications

This article reviews the nature of modern and ancient soils. Soils are naturally occurring bodies that mantle most of the land surface of the Earth. They are found on virtually every part of the Earth’s land surface, other than areas covered by water bodies (lakes and rivers), glacial ice, or steep slopes in mountainous terrain. Soils occur at the interface of the geosphere, hydrosphere, biosphere, and atmosphere and are the medium of growth for much of the Earth’s plant and animal life. The study of soils as naturally occurring bodies on the Earth’s surface is called pedology (in contrast to …


Curation Techniques Of Small-Sized Natural History Specimens: A Collection Of Microfossils., Zachary V Biven-Leslie, Guillermo W. Rougier Jan 2021

Curation Techniques Of Small-Sized Natural History Specimens: A Collection Of Microfossils., Zachary V Biven-Leslie, Guillermo W. Rougier

Undergraduate Arts and Research Showcase

Small-sized fossil specimens are challenging regarding safety, storage and traceability of information. A recent collection of several hundred minute early mammalian teeth and jaws (most about 1mm) made impossible the standard practices of specimen numbering. A reliable association of the specimen and the collection number is the minimum required, however, a number of other data easily recoverable from the specimen/curating material is desirable. Geological provenance, locality, systematic and anatomical ID, collector, year, etc. is often included if possible. Use of the specimen is expected to be on the order of hundreds of years, manipulated by investigators, transported, and stored in …


Using Landslide-Inventory Mapping For A Combined Bagged-Trees And Logistic-Regression Approach To Determining Landslide Susceptibility In Eastern Kentucky, Usa, Matthew M. Crawford, Jason M. Dortch, Hudson J. Koch, Ashton A. Killen, Junfeng Zhu, Yichuan Zhu, Lindsey Sebastian Bryson, William C. Haneburg Jan 2021

Using Landslide-Inventory Mapping For A Combined Bagged-Trees And Logistic-Regression Approach To Determining Landslide Susceptibility In Eastern Kentucky, Usa, Matthew M. Crawford, Jason M. Dortch, Hudson J. Koch, Ashton A. Killen, Junfeng Zhu, Yichuan Zhu, Lindsey Sebastian Bryson, William C. Haneburg

Faculty, Staff, and Affiliated Publications--KGS

High-resolution LiDAR-derived datasets from a 1.5 m digital elevation model and a detailed landslide inventory (n ≥ 1000) for Magoffin County, Kentucky, USA were used to develop a combined machine-learning and statistical approach to improve geomorphic-based landslide-susceptibility mapping.

An initial dataset of 36 variables was compiled to investigate the connection between slope morphology and landslide occurrence. Bagged trees, a machine-learning random-forest classifier, was used to evaluate the geomorphic variables, and 12 were identified as important: standard deviation of plan curvature, standard deviation of elevation, sum of plan curvature, minimum slope, mean plan curvature, range of elevation, sum of roughness, …


Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright Jan 2021

Artisanal Mining Impacts In Urbanized Semi-Arid Environments: Lessons From Historic Arsenic Mining Near San Diego, California, James A. Wright

Theses

Anomalously elevated arsenic concentrations occur at an abandoned artisanal mine site in an open space recreational park in urban San Diego County, California. Although mining at the site ceased 100 years ago little to no remediation efforts took place leaving shafts, adits, waste piles and derelict infrastructure accessible by inquisitive hikers and adventurers frequenting Black Mountain Open Space Park. This study evaluates the geochemical mechanisms of As transport downgradient from the mine and examines the contribution of both climate and urbanization on the restriction of As mobility. Sediment As concentrations reach 2,320 mg/kg (483 times background crustal concentrations; n=73) along …


High Frequency Concurrent Measurements In Watershed And Impaired Estuary Reveal Coupled Doc And Decoupled Nitrate Dynamics, Gopal K. Mulukutla, Wilfred Wollheim, Joseph Salisbury, Richard O. Carey, Thomas Gregory, William H. Mcdowell Jan 2021

High Frequency Concurrent Measurements In Watershed And Impaired Estuary Reveal Coupled Doc And Decoupled Nitrate Dynamics, Gopal K. Mulukutla, Wilfred Wollheim, Joseph Salisbury, Richard O. Carey, Thomas Gregory, William H. Mcdowell

All Materials

Rapid changes in land use, pollution inputs, and climate are altering the quantity, timing and form of materials delivered from watersheds to estuaries. To better characterize these alterations simultaneous measurements of biogeochemical conditions in watersheds and estuaries over a range of times scales are needed. We examined the strength of watershed-estuarine biogeochemical coupling using data of in situ measurements of nitrate, terrestrial dissolved organic carbon (DOC) and chloride collected over a seven-month period in a nitrogen impaired estuary in the northeastern US. The watershed was observed exerting strong control over concentrations of terrestrially derived DOC in the estuary, attributable to …


Quantifying Shape Of Star-Like Objects Using Shape Curves And A New Compactness Measure, Gopal K. Mulukutla, Emese Hadnagy, Matthew Fearon, Edward Garboczi Jan 2021

Quantifying Shape Of Star-Like Objects Using Shape Curves And A New Compactness Measure, Gopal K. Mulukutla, Emese Hadnagy, Matthew Fearon, Edward Garboczi

All Materials

Shape is an important indicator of the physical and chemical behavior of natural and engineered particulate materials (e.g., sediment, sand, rock, volcanic ash). It directly or indirectly affects numerous microscopic and macroscopic geologic, environmental and engineering processes. Due to the complex, highly irregular shapes found in particulate materials, there is a perennial need for quantitative shape descriptions. We developed a new characterization method (shape curve analysis) and a new quantitative measure (compactness, not the topological mathematical definition) by applying a fundamental principle that the geometric anisotropy of an object is a unique signature of its internal spatial distribution …


Great South Bay, Long Island, New York Summer Phytoplankton Identification & Monitoring Program, Cercom, Molloy University, John Tanacredi Ph.D., Kyle F. Maurelli Jan 2021

Great South Bay, Long Island, New York Summer Phytoplankton Identification & Monitoring Program, Cercom, Molloy University, John Tanacredi Ph.D., Kyle F. Maurelli

CERCOM Reports

Phytoplankton Collection Methodologies: 80 micron Plankton Tow Net with sample bottle attachment

Phytoplankton Protocol: 1.Gather Samples 2.Make one slide per sample 3.View slides using microscope connected with computer 4. Record findings using “ Row # “ and “ Colum letter “ 5. Record using “ Tally’s “ per species found within sample 6. Capture anything interesting “ Take Picture “ 7.Duplicate pictures taken 8.Make sure measurement of species found is taken 9. Email Jennifer Maucher at [email protected] , include pictures, questions and names of the species you “guess” you found.


Lift In The Vertical Shear Of Southerly Jet Embedded In A Uniform Westerly Flow, Qi Hu, George Limpert Jan 2021

Lift In The Vertical Shear Of Southerly Jet Embedded In A Uniform Westerly Flow, Qi Hu, George Limpert

Department of Earth and Atmospheric Sciences: Faculty Publications

A new mechanism is proposed as a potential cause for the one-third of warm season severe nocturnal convection in the U.S. Great Plains that develops in environments without the presence of air mass boundaries of fronts or mesoscale systems. This mechanism is tested in two- and three dimensional models. Results show strong ascent (~1.0 m/s) sufficient for nocturnal convection initiation, arising from interactions of mean westerly zonal wind with the vertical shear of a northern vortex and also perturbation westerly winds that are created by the Coriolis torque on the Great Plains southerly low-level jet. The interaction involving the northern …


Aeolian Sand Stringers In The Upper Midwest, Usa: Morphology, Stratigraphy, And Paleoenvironmental Significance, Kenzie L. Shandonay Jan 2021

Aeolian Sand Stringers In The Upper Midwest, Usa: Morphology, Stratigraphy, And Paleoenvironmental Significance, Kenzie L. Shandonay

All Graduate Theses, Dissertations, and Other Capstone Projects

Sand stringers are subtle (~1-10 m high), elongate (several km long, up to 100 m wide) aeolian landforms that lack a slip face and generally have a northwest-southeast orientation. They are ubiquitous across the Upper Midwest, including southeast Minnesota and western Wisconsin. Despite their prevalence, the timing, processes, and environmental conditions during sand stringer formation and evolution are poorly understood. This research aims to describe sand stringer morphology and stratigraphy, reconstruct regional paleoclimate, and characterize the timing and geomorphic processes of sand stringer formation and evolution in response to shifts in environmental conditions. This study investigates two sand stringers: Good-1 …


Neogene Dinoflagellate Cysts From The Tropical Americas, Damian Cardenas Jan 2021

Neogene Dinoflagellate Cysts From The Tropical Americas, Damian Cardenas

Doctoral Dissertations

"Marine palynomorphs, mainly dinoflagellate cysts and acritarchs, constitute excellent proxies for biostratigraphic and paleoceanographic studies in neritic sequences. Neogene marine palynological studies have mostly focused on the Northern Hemisphere, resulting in the scarcity of dinoflagellate cysts and acritarchs from tropical latitudes. Forty samples encompassing the late Chattian-late Burgidalian time interval (~24.1- 17.3 Ma) in the Southern Caribbean were analyzed for their marine palynological contents. A biostratigraphic scheme for the region is proposed and includes the upper Chattian-lower Aquitanian Minisphaeridium latirictum Interval Zone (~23.9-22.0 Ma), the upper Aquitanian Achomosphaera alcicornu Interval Zone (~22.0-20.3 Ma), and the Burdigalian Cribroperidinium tenuitabulatum Interval Zone …


Spatiotemporal Variations Of Upper Crustal Anisotropy Along The San Jacinto Fault Zone In Southern California And The Fairview Region In Central Oklahoma, Enyuan Jiang Jan 2021

Spatiotemporal Variations Of Upper Crustal Anisotropy Along The San Jacinto Fault Zone In Southern California And The Fairview Region In Central Oklahoma, Enyuan Jiang

Doctoral Dissertations

"To discern spatial and explore the possible existence of temporal variations of upper crustal anisotropy along an ~15 km section of the San Jacinto Fault Zone (SJFZ) in California, and in the Fairview, Oklahoma, region, we conduct systematic shear wave splitting (SWS) investigations using local S-wave data recorded by seismic stations. Strong spatial variations in crustal anisotropy are revealed by 1694 and 405 pairs of splitting parameters (including the fast polarization orientation and the splitting time), respectively. For both areas, for raypaths traveling through the fault zones, the fast orientations are parallel to the faults and may be attributed to …


Receiver Function Imaging Of The 410 And 660 Km Discontinuities And Seismic Azimuthal Anisotropy Revealed By Shear Wave Splitting Beneath The Australian Continent, Kailun Ba Jan 2021

Receiver Function Imaging Of The 410 And 660 Km Discontinuities And Seismic Azimuthal Anisotropy Revealed By Shear Wave Splitting Beneath The Australian Continent, Kailun Ba

Doctoral Dissertations

"The Australian continent is composed the of Precambrian cratons in the west and Phanerozolc orogens in the east. Despite numerous seismological studies, controversies remain regarding the structure, evolution, and dynamics of the crust and mantle beneath Australia. In this study, we used two techniques, receiver functions and shear wave splitting analyses, to investigate the topography of the mantle transition zone (MTZ) discontinuities and mantle seismic azimuthal anisotropy, respectively. We utilized P-to-S receiver functions to map the 410 and 660 km discontinuities bordering the MTZ. The discontinuity depths obtained show a systematic apparent uplifting for both discontinuities in central and western …


The Pilot Knob Magnetite, Pilot Knob Hematite, And Shepherd Mountain Iron Oxide Deposits In Southeast Missouri -- Local Expressions Of A Magmatic-Hydrothermal Plumbing System?, Bolorchimeg N. Tunnell Jan 2021

The Pilot Knob Magnetite, Pilot Knob Hematite, And Shepherd Mountain Iron Oxide Deposits In Southeast Missouri -- Local Expressions Of A Magmatic-Hydrothermal Plumbing System?, Bolorchimeg N. Tunnell

Doctoral Dissertations

“The Southeast Missouri Iron Metallogenic Province in the Midwestern USA contains seven major and several minor IOA/IOCG-type deposits, all of which are spatially associated with the early Mesoproterozoic (1.50-1.44 Ga) magmatism in the St. Francois Mountains terrane. This Ph.D. project focuses on the Pilot Knob deposits, i.e., the deeper largely massive Pilot Knob Magnetite (PKM) and the shallower Pilot Knob Hematite (PKH) deposits, and the Shepherd Mountain deposit that are located less than 2.1 km distance from one another. The first precise age for the formation of the PKM ore is constrained at 1438±5.8 Ma using apatite U-Pb method. Petrographic …


Community-Scale Beach Nourishment And Groin Construction Decisions Along Human-Modified Coasts : The Interplay Between Socioeconomics, Coordination, Tourism, And Shoreline Change, Arye Max Janoff Jan 2021

Community-Scale Beach Nourishment And Groin Construction Decisions Along Human-Modified Coasts : The Interplay Between Socioeconomics, Coordination, Tourism, And Shoreline Change, Arye Max Janoff

Theses, Dissertations and Culminating Projects

In response to coastal erosion driven by storms, sea-level rise, and local gradients in sediment supply, communities defend their homes and maintain beach recreation by widening beaches via soft engineering (i.e., beach nourishment) or hard engineering (i.e., groins). Past research has found that, at regional scales, the net effect of these interventions has in many cases not only counteracted historically observed beach erosion, but has reversed erosional trends, on average shifting shorelines seaward. While groins trap sediments locally at and upcoast of the structure relative to the direction of alongshore transport, however, they often have adverse downcoast impacts, resulting in …


Miocene To Present Oceanographic Variability In The Scotia Sea And Antarctic Ice Sheets Dynamics: Insight From Revised Seismic-Stratigraphy Following Iodp Expedition 382, Lara F. Pérez, Yasmina M. Martos, Marga García, Michael E. Weber, Maureen E. Raymo, Trevor Williams, Fernando Bohoyo, Linda Armbrecht, Ian Bailey, Stefanie Brachfeld, Anna Glüder, Michelle Guitard, Marcus Gutjahr, Sidney Hemming, Iván Hernández-Almeida, Frida S. Hoem, Yuji Kato, Suzanne O'Connell, Victoria L. Peck, Brendan Reilly, Thomas A. Ronge, Lisa Tauxe, Jonathan Warnock, Xufeng Zheng Jan 2021

Miocene To Present Oceanographic Variability In The Scotia Sea And Antarctic Ice Sheets Dynamics: Insight From Revised Seismic-Stratigraphy Following Iodp Expedition 382, Lara F. Pérez, Yasmina M. Martos, Marga García, Michael E. Weber, Maureen E. Raymo, Trevor Williams, Fernando Bohoyo, Linda Armbrecht, Ian Bailey, Stefanie Brachfeld, Anna Glüder, Michelle Guitard, Marcus Gutjahr, Sidney Hemming, Iván Hernández-Almeida, Frida S. Hoem, Yuji Kato, Suzanne O'Connell, Victoria L. Peck, Brendan Reilly, Thomas A. Ronge, Lisa Tauxe, Jonathan Warnock, Xufeng Zheng

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Scotia Sea and the Drake Passage is key towards understanding the development of modern oceanic circulation patterns and their implications for ice sheet growth and decay. The sedimentary record of the southern Scotia Sea basins documents the regional tectonic, oceanographic and climatic evolution since the Eocene. However, a lack of accurate age estimations has prevented the calibration of the reconstructed history. The upper sedimentary record of the Scotia Sea was scientifically drilled for the first time in 2019 during International Ocean Discovery Program (IODP) Expedition 382, recovering sediments down to ∼643 and 676 m below sea floor in the Dove …


Marine Anoxia And Ocean Acidification During The End-Permian Extinction: An Integrated View From Δ238u And Δ44/40ca Proxies And Earth System Modeling, Ying Cui, Feifei Zhang, Jiuyuan Wang, Shijun Jiang, Shuzhong Shen Jan 2021

Marine Anoxia And Ocean Acidification During The End-Permian Extinction: An Integrated View From Δ238u And Δ44/40ca Proxies And Earth System Modeling, Ying Cui, Feifei Zhang, Jiuyuan Wang, Shijun Jiang, Shuzhong Shen

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The largest mass extinction event in the Phanerozoic, known as the end-Permian mass extinction (or EPME, ca. 252 Ma) is coincident with the main eruption phase of Siberian Traps volcanism (ca. 252 to 250 Ma), a large igneous province (LIP). This LIP is estimated to have a volume larger than 2 × 106 km3 and to have released both mantle carbon dioxide (CO2) through extrusions and thermogenic methane (CH4) and carbon dioxide (CO2) through intrusions. The climatic consequences of these greenhouse gases is detrimental to both marine and terrestrial life and may have delayed the recovery of ecosystems …


Geological And Environmental Sciences - 2021, Dept. Of Geological And Environmental Sciences Jan 2021

Geological And Environmental Sciences - 2021, Dept. Of Geological And Environmental Sciences

Geological and Environmental Sciences News

  • Greetings from the Department Chair
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  • In the News 2020-21 Awards and Accolades
  • From the Advisory Council
  • 2021 Distinguished Alumni Lisa Phillips
  • In Remembrance
  • Publications and New Grants
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Detection And Interpretation Of Precursory Magnetic Signals Preceding October 30, 2020 Samos Earthquake, İlki̇n Özsöz, Oya Ankaya Pamukçu Jan 2021

Detection And Interpretation Of Precursory Magnetic Signals Preceding October 30, 2020 Samos Earthquake, İlki̇n Özsöz, Oya Ankaya Pamukçu

Turkish Journal of Earth Sciences

A major earthquake (Mw=7.0) occurred in the Samos Island on the 30th of October 2020 at 11:51 UTC. Swarm satellite magnetic data were analysed for 153 days before and 46 days after the earthquake. Preearthquake and postearthquake anomaly search is constrained within the Dobrovolsky's Circular Area. Fundamentally, there are 5 steps for processing satellite magnetic data to interpret the earthquake preparation phase. The first step is converting geographical coordinates to geomagnetic latitude and longitude. Secondly, intensity of the external magnetic field should be evaluated by magnetic indices (Ap, Kp and Dst). Thirdly, preearthquake and postearthquake magnetic anomaly should be constrained …


Seismic A And B-Values And Crustal Parameters Of Samos Island-Aegean Sea, Lesvosisland-Karaburun, Kos Island-Gökova Bay Earthquakes, Oya Pamukçu, Fi̇kret Doğru, Ayça Çirmik, Düzgün Göneş Jan 2021

Seismic A And B-Values And Crustal Parameters Of Samos Island-Aegean Sea, Lesvosisland-Karaburun, Kos Island-Gökova Bay Earthquakes, Oya Pamukçu, Fi̇kret Doğru, Ayça Çirmik, Düzgün Göneş

Turkish Journal of Earth Sciences

In recent years, seismicity has increased considerably in the Aegean Sea region and there have been earthquakes in which people lost their lives. The major earthquakes, Kos Island-Gökova Bay (Mw = 6.6), Lesvos Island-Karaburun (İzmir) (Mw = 6.2) and Samos Island-Aegean Sea (Mw = 6.9) occurred in the Aegean Sea and affected Aegean region strongly. Within the scope of this study, the seismic b-value of these major earthquakes was calculated in order to perform earthquake statistical analysis. Seismic a and b-values within the first 24 h and 14 days after the mainshock determination of Kos Island-Gökova Bay, Lesvos Island-Karaburun (İzmir) …