Geology Commons^™

Novel Application Of 210po-210pb Disequilibria To Date Snow, Melt Pond, Ice Core, And Ice-Rafted Sediments In The Arctic Ocean, Mark Baskaran, Katherine Krupp, Mark Baskaran

Environmental Science and Geology Faculty Research Publications

We collected surface ocean water, snow, grab ice, ice core, melt pond and ice-rafted sediment (IRS) from 5 ice stations during the Western Arctic US GEOTRACES cruise (USGCG Healy; August 10 – October 7, 2015) and analyzed for 210Po (T1/2 = 138.4 days) and 210Pb (T1/2 = 22.3 years) in dissolved and particulate phases (snow, grab ice, ice core, surface seawater) to investigate the 210Po:210Pb disequilibria in these matrices. Thirteen aerosol samples, using a large-volume aerosol sampler (PM10), from Dutch Harbor, AK to North Pole, were also collected and analyzed for 210Po/210Pb to quantify the atmospheric depositional input to the …

Integrated Geophysical Analysis Over Bathymetrists Seamounts And The Sierra Leone Rise, Alexa Fernandez

UCARE: Research Products

The Bathymetrists Seamounts (BSM) are located northeast of the Sierra Leone Rise in the Atlantic Ocean. The northern seamounts have a southwest to northeast trend which is contrary to the current eastward motion of the African tectonic plate where they reside. The geological history and crustal structures of these features are poorly understood. The goal of this study is to integrate multiple geophysical data to better understand the crustal architecture and tectonic history of the BSM.

The seismic refraction study from Jones et al. (2015) was used as the baseline for isostatic modeling. This dataset suggested the presence of magmatic …

210po And 210pb As Tracers Of Particle Cycling And Export In The Western Arctic Ocean, Wokil Bam, Kanchan Maiti

Environmental Science and Geology Faculty Research Publications

The distribution and vertical fluxes of particulate organic carbon and other key elements in the Arctic Ocean are primarily governed by the spatial and seasonal changes in primary productivity, areal extent of ice cover, and lateral exchange between the shelves and interior basins. The Arctic Ocean has undergone rapid increase in primary productivity and drastic decrease in the areal extent of seasonal sea ice in the last two decades. These changes can greatly influence the biological pump as well as associated carbon export and key element fluxes. Here, we report the export of particulate organic and inorganic carbon, particulate nitrogen …

Developing A Database Of Seismic Data Over The Cascadia Subduction Zone, Khawlh Al Farsi

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

An inevitable megathrust earthquake is expected in the Cascadia subduction zone that will affect the population of the coast of southwestern British Columbia and the northwest of the United States. In this active tectonic margin, the Juan de Fuca oceanic plate is subducting beneath the North American continental plate, causing unevenly distributed seismic activity. The major goal of this geophysical research project is to study the tectonic structures of the Cascadia subduction zone in order to comprehend the geology of the region and investigate the seismic hazards. The primary objective of this project is to develop a geophysical database of …

40 Sets Of Strong Ground Motion Records Convey All Design Response Spectrums Located In Tartous, Syria, Dr. Seraj Jdyd

Journal of the Arab American University مجلة الجامعة العربية الامريكية للبحوث

Selecting seismic records in Global Standards is, until now, based on matching design response spectrum, where records should have seismological characteristics similar to the expected earthquake for the considered site (magnitude, distance, fault mechanism and soil conditions). Then it is necessary to scale these records to match the intensity of the earthquake expected for the site. Generally, scaling can be made by ground motions uniform scaling in time domain to best match (in average) the target spectrum within a period range of interest. Design ground motions are typically prescribed by smooth response spectra. But it is preferred to use a …

Single-Crystal Elasticity Of Tremolite At High-Pressure Conditions And Its Implication For The Mid-Lithospheric Discontinuity, Soisiri Charin

Earth and Planetary Sciences ETDs

Tremolite is the calcium magnesium amphibole that widely occurs in igneous and metamorphic rocks of the crustal and upper mantle lithosphere, especially in the greenschist facies to amphibolite facies of ultramafic assemblages. The stability field of amphibole reaches 3-4 GPa and 1100-1200°C depending on water content and cation substitutions giving rise to amphibole to occur in highly variable compositions. This P-T condition, corresponding to the depth about 80-120 km, coincides with the depth range that a negative velocity gradient usually found within most stable cratonic lithospheres. This depth range is seismically called Mid-lithosphere discontinuity (MLD). The geologic processes that might …

Rezina Shams – The First Known Woman Geologist From Dhaka University (Bangladesh) To Obtain A Phd, Nazrul I. Khandaker

Publications and Research

Rezina Shams (Dhaka University geology graduate 1985; née Rezina Bashar) is the first known female geologist from Bangladesh to obtain a PhD in 1991 (University of Birmingham, UK). Rezina’s undergraduate and graduate education in geology at Dhaka University (DU) was at a time when only a handful of female students attended the program. Rezina’s debut into her geology career began with the Master Plan Organisation (MPO) and then the Bangladesh Atomic Energy Commission (1986). Rezina kept her aspirations alive, and eventually furthered her geoscience education to a PhD. Upon receiving a PhD in 1991 from the University of Birmingham under …

Causes And Characteristics Of Electrical Resistivity Variability In Shallow (<4 M) Soils In Taylor Valley, East Antarctica, William S. Gutterman

LSU Master's Theses

The McMurdo Dry Valleys are the largest ice-free region in Antarctica and are characterized as a polar desert environment. Soils in the region are typically very dry (<1% soil water by weight) and remain frozen for most of the year. Increases in air temperature and incoming solar radiation during the austral summer generate meltwater from glaciers, ground ice, and snow patches supplying moisture to soils and altering the physical and chemical makeup of the subsurface. Previous studies have utilized airborne electromagnetic surveys (AEM) to analyze groundwater systems in the deep subsurface but have not yet examined soil moisture in the shallow (<4 m) subsurface. Here, I used electrical resistivity data from two AEM surveys (2011 and 2018) and soil geochemical data from three transects to characterize the spatial heterogeneity of soil properties in the near-subsurface of lower Taylor Valley. Soil resistivities from 2011 and 2018 range from 33.2 Ωm to 3535 Ωm with low elevations of <100 meters above sea level (masl) typically displaying the lowest resistivities and high elevations displaying greater resistivities. Liquid brine fractions were empirically estimated from electrical resistivity values using Archie’s Law and range from 0.3% to 68.2% for soils with resistivities <200 Ωm. Additionally, soil transect data show greater percentages of fine-grained sediments (<63 µm) exist at elevations <100 masl where soil resistivities begin decreasing. Resistivity variability in the subsurface is ultimately controlled by the site history, local and regional climate, soil salinity, soil moisture, soil lithology.

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Ice-Crystal Traces Imply Ephemeral Freezing In Early Permian Equatorial Pangea, Lily S. Pfeifer, Brooke A. Birkett, Jean Van Den Driessche, Stephane Pochat, Geriliyn S. Soreghan

School of Earth & Environment Departmental Research

Delicate impressions in lacustrine strata of the lower Permian (lower Cisuralian) Usclas Formation record ephemeral freezing in equatorial Pangea. These sediments accumulated in the paleoequatorial and intramontane Lodève Basin (southern Massif Central, France) during peak icehouse conditions of the Late Paleozoic Ice Age. Experimental replication of these features supports the interpretation that they are ice-crystal molds. Evidence for films of ice in marginal-lacustrine sediment at such low latitudes and inferred low to moderate altitudes (1–2 km) calls for a reevaluation of climate conditions in eastern equatorial Pangea. Ephemeral freezing implies either cold tropical temperatures (~5 °C cooler than the Last …

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