Browsing Geology by Title
Now showing items 1-20 of 172
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182W and HSE constraints from 2.7 Ga komatiites on the heterogeneous nature of the Archean mantle
(Elsevier - Geochimica et Cosmochimica Acta, 2018)While the isotopically heterogeneous nature of the terrestrial mantle has long been established, the origin, scale, and longevity of the heterogeneities for different elements and isotopic systems are still debated. Here, ... -
Advection-Diffusion Controlled Lithium Isotopic Distribution in Contact Aureoles: A Case Study from the Florence County Pegmatites, Wisconsin
(2009)Stable isotopes are useful tracers of fluid-rock interactions in contact aureole settings. To date, only a few case studies have used Li isotopes to study fluid-rock interactions in contact aureole settings. These studies ... -
Age, composition, and origin of the lower continental crust, northern Tanzania
(2008)Granulite xenoliths from the East African rift in Tanzania sample the lower continental crust beneath both the stable Tanzanian craton and the adjacent, polymetamorphic Mozambique belt. Protoliths of surface rocks in both ... -
ANALYZING TIME-VARYING SEISMICITY AND AFTERSHOCK BEHAVIOR IN CENTRAL AND EASTERN UNITED STATES
(2021)Central and Eastern United States (CEUS) earthquakes are far less common than those in the tectonically active west coast, but the significance is elevated for a few reasons. Due to older, harder, and often denser rocks ... -
Anatexis and crustal differentiation: Insights from the Fosdick migmatite-granite complex, West Antarctica
(2014)In the Fosdick migmatite-granite complex of West Antarctica, U-Pb geochronology of monazite in migmatites and zircon in granites records two episodes of high-temperature metamorphism, one in the Devonian-Carboniferous and ... -
APPLYING GEODESY TO MODEL POSTSEISMIC SLIP OF THE 2016 MW 6.4 MEINONG EARTHQUAKE
(2019)In regions of rapid convergence such as southwest Taiwan, unmapped active structures at multiple depths increase the uncertainty of seismic hazard estimates. The 2016 Mw 6.4 MeiNong earthquake occurred below the main Taiwan ... -
Assessing the Oxidative History of Miller Range Martian Meteorites
(2016)Miller Range (MIL) Martian meteorites are oxidized nakhlites. Early studies attribute their oxidation to reduction-oxidation reactions involving assimilated sulfate. I utilize the sulfur isotope and major element composition ... -
Authigenesis, biomineralization, and carbon-sulfur cycling in the Ediacaran ocean
(2015)Fossil record of the Ediacaran Period (635-541 Ma) reveals unprecedented rise of early animal life (metazoan) in Earth history. Coupled with this evolutionary milestone, the Earth’s atmosphere and hydrosphere experienced ... -
BRITTLE FAULTING IN POROUS, WATER-SATURATED SANDSTONE DEFORMED UNDER HIGH PORE FLUID PRESSURE
(2020)The effective stress law is widely used to model the deformation of crustal rock. It states that effective pressure, the difference between confining pressure and pore fluid pressure, dictates rock strength. In low-porosity ... -
A carbon and nitrogen isotopic analysis of Pleistocene food webs in North America: implications for paleoecology and extinction
(2008-05-05)Carbon and nitrogen isotopic reconstructions of North American Pleistocene trophic relationships were used to examine the extinction within terrestrial mammals ~10,000 years ago and distinguish between two potential causal ... -
Characterization of the regional, crustal, and global distribution and abundance of the heat producing elements and their geoneutrino flux
(2019)The amount and distribution of radiogenic power generation from the heat producing elements (HPE) U, Th, and K in the Earth is not well constrained. Compositional estimates of these elements vary by a factor of three in ... -
Characterization of the spatial differences in hydrological functioning in a tidal marsh, Patuxent River, MD: A framework for understanding nutrient dynamics
(2004-12-08)This study investigates spatial variations in sediment hydraulic conductivity (K), network channel shape and horizontal groundwater flux magnitude toward tidal network channels in a freshwater tidal marsh. Results showed ... -
Characterizing 3-dimensional Melt Distribution and Anisotropic Permeability in Sheared Partially Molten Rocks
(2020)With increasing shear strain, initially homogeneously distributed melt can segregate into an array of melt-rich bands, flanked by melt-poor regions. To address how the formation of these melt-rich bands affects the transport ... -
CHARACTERIZING THE DURATION, PERIODICITY AND CHEMICAL IMPACT OF FLUID TRANSPORT IN THE SUBDUCTING SLAB: INSIGHTS FROM ISOTOPE GEOCHEMISTRY OF HIGH-PRESSURE METAMORPHOSED OCEANIC CRUST
(2021)Subduction zones are key loci of geochemical cycling and natural hazards on Earth including large earthquakes and explosive volcanic eruptions. Fluids produced during subduction are thought to play a role in all these ... -
A CHEMICAL AND ISOTOPIC COMPARISON OF TWO 1ST-ORDER AGRICULTURAL TRIBUTARIES, KENT COUNTY, MARYLAND
(2005-05-27)Nitrate derived predominantly from agricultural fertilizers results in algal blooms and wide-spread anoxia in estuarine environments. Roughly half the nitrate delivered to the Chesapeake Bay is derived from groundwater ... -
Climate Change During Intervals Of The Past Millennium In The Southwestern Tropical Pacific
(2018)Limited observations from the tropical Pacific over the past millennium make it difficult to assess whether different time periods had significant variations in El Nino-Southern Oscillation (ENSO) amplitude and frequency. ... -
Collective phenomena in granular and atmospheric electrification
(2015-07-29)This repository contains data from the Granular Electrification Experiment in the University of Maryland Nonlinear Dynamics Lab. The experiment consists of a cylindrical cell with aluminum plates on the top and bottom. The ... -
Combined Lithophile-Siderophile Isotopic Constraints on Hadean Processes Preserved in Ocean Island Basalt Sources
(American Geophysical Union - Geochemistry, Geophysics, Geosystems, 2021)Detection of Hadean isotopic signatures within modern ocean island basalts (OIB) has greatly influenced understanding of Earth's earliest history and long-term dynamics. However, a relationship between two isotopic tools ... -
Comment on: Aquatic adaptation in the skull of carnivorous dinosaurs (Theropoda: Spinosauridae) and the evolution of aquatic habits in spinosaurids. 93: 275–284
(2022-06)In a recent paper, the contention that spinosaurine theropods were semi-aquatic was supported by Arden et al., (2019) and they provided a hypothetical sequence of acquisition of traits that had evolved in line with this ... -
Constraining Lithospheric Structure across the Continental Borderland using Receiver Functions
(2014)Due to its complex history of deformation, which includes subduction, rifting, and transtensional motions, the California Continental Borderland provides an interesting geological setting for studying how the structure ...