Browsing Geology by Title
Now showing items 52-71 of 172
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GENETICS, AGES, AND CHEMICAL COMPOSITIONS OF IRON METEORITES
(2020)Comparison of genetic isotopic compositions of iron meteorites with metal-silicate segregation ages suggests that the isotopic composition of the NC reservoir changed with time. By contrast, no such age-linked changes in ... -
A Geochemical and Osmium Isotopic Study of Group IVB Irons and Ungrouped Irons Chinga, Tishomingo and Willow Grove
(2007-01-23)Re-Os isotopic and highly siderophile element (HSE) systematics of IVB irons and ungrouped iron meteorites Chinga, Tishomingo and Willow Grove are presented. IVB iron composition has been constrained by HSE (Re, Os, Ru, ... -
Geochemical and Radiometric Constraints on the Redox History of Late Ediacaran Oceans
(2012)Over the past decade, significant field and laboratory studies have been devoted to furthering understanding of the chemical conditions that accompanied the origin and diversification of Earth's earliest multicellular ... -
THE GEOCHEMICAL BEHAVIOR OF SCANDIUM DURING FRACTIONAL CRYSTALLIZATION AND IMPLICATIONS FOR ORE FORMATION
(2020)Demand for scandium is increasing due to the use of scandium-aluminum alloys in the aerospace and sporting goods industries, and in solid-oxide fuel cells. Scandium deposits are associated with mafic intrusions and laterites, ... -
Geochemistry of crustal formation and evolution
(2016)Terrestrial planets produce crusts as they differentiate. The Earth’s bi-modal crust, with a high-standing granitic continental crust and a low-standing basaltic oceanic crust, is unique in our solar system and links the ... -
Geodynamic implications of ophiolitic chromitites in the La Cabaña ultramafic bodies, Central Chile
(Taylor & Francis Group - International Geology Review, 2014)Chromitites (>80% volume chromite) hosted in two ultramafic bodies (Lavanderos and Centinela Bajo) from the Palaeozoic metamorphic basement of the Chilean Coastal Cordillera were studied in terms of their chromite ... -
Geomorphic and Hydrologic Controls on Tidal Prism and Inlet Cross Sectional Area for Chesapeake Bay Lagoons
(2011)Previous studies have defined a power function between tidal prism and inlet cross sectional area for many lagoon systems. The goals of this study are to first, determine underlying processes that generate the area-prism ... -
Geomorphic, hydraulic, and biogeochemical controls on nitrate retention in tidal freshwater marshes
(2012)Tidal freshwater wetlands are ideal sites for nitrate retention because of their position within the landscape (near the head of tide); they receive water, discharge, nutrients (N and P), and sediment loads directly from ... -
Geophysical Exploration of Terrestrial and Lunar Volcanic Fields
(2021)Planetary analogs are environments representative of current or past conditions on other planetary bodies. My research uses terrestrial volcanic fields as lunar analogs to conduct geophysical studies on the subsurface ... -
GLOBAL AND REGIONAL REFERENCE MODELS FOR PREDICTING THE GEONEUTRINO FLUX AT SNO+, SUDBURY, CANADA
(2013)Determining the radiogenic heat power that is driving plate tectonics and mantle convection is fundamentally important to understanding the Earth's heat budget and its thermal and chemical evolution. The radiogenic heat ... -
Gold distribution in the Archean Tanzanian Craton: Evaluating the effects of intracrustal differentiation
(2013)This study evaluates the vertical distribution of gold in the continental crust. Implementing a recently published method by Pitcairn et al. (2006a) for the chromatographic separation of gold from acid-digested rocks using ... -
Groundwater Variations from Autocorrelation and Receiver Functions
(2019)This dataset supports the following research: Using a 20-year continuous broadband record and two independent single-station techniques – ambient noise autocorrelation and receiver functions – we document a relationship ... -
HIGH PRESSURE REDOX GEOCHEMISTRY OF TUNGSTEN IN METAL-SILICATE SYSTEMS: IMPLICATIONS FOR CORE FORMATION IN THE EARTH
(2011)Geochemical models of core formation are commonly based on core and mantle abundances of siderophile elements. Because of the affinity of these elements for metallic phases, they are thought to be highly concentrated in ... -
High-Precision Tungsten Isotopic Analysis by Multicollection Negative Thermal Ionization Mass Spectrometry Based on Simultaneous Measurement of W and 18O/16O Isotope Ratios for Accurate Fractionation Correction
(ACS Publications, 2016-01-11)Determination of the 182W/184W ratio to a precision of ±5 ppm (2σ) is desirable for constraining the timing of core formation and other early planetary differentiation processes. However, WO − ... -
Highly Siderophile Element and Tungsten Systematics of Hawaiian Picrites
(2009)A suite of Hawaiian picrites (MgO > 13 wt.%), and associated basalts, that represent some of the most primitive melts from the Hawaiian mantle source regions were analyzed for their W, highly siderophile element (HSE: Os, ... -
Highly Siderophile Elements and the Rhenium-Osmium System in Chondritic Components
(2012)Chondritic meteorites and their components provide information about the early solar system, as well as processes that affected meteorite parent bodies post-accretion. The rare earth element (REE) abundances, highly ... -
Highly Siderophile Elements, 187Re-187Os and 182Hf-182W Isotopic Systematics of Early Solar System Materials: Constraining the Early Evolution of Chondritic and Achondritic Parent Bodies
(2016)Highly siderophile element (HSE) abundances and 187Re-187Os isotopic systematics for H chondrites and ungrouped achondrites, as well as 182Hf-182W isotopic systematics of H and CR chondrites are reported. Achondrite ... -
Hydrograph separation analyses to determine runoff sources in a large, urban watershed
(2010)Hydrograph separation techniques were used to determine contributions of old and new water during storm events at four sites within the urban Anacostia River watershed. Multiple storm hydrographs were successfully separated ... -
HYDROLOGICAL, BIOLOGICAL, AND GEOCHEMICAL RELATIONSHIPS AMONG CARBON, NITROGEN, AND BASE CATIONS IN RESTORED AND UNRESTORED URBAN STREAMS
(2017)Urban infrastructure changes hydrologic flowpaths of water into streams and alters ecosystem function. Geomorphic stream restoration is commonly implemented to stabilize channels, while ecosystem function, and nutrient ... -
Hydrothermally Altered Basalt as a Source for Indium in Ore Deposits
(2018)Indium is an element integral to various emerging technologies. Despite the demand for indium, little is known about its geochemical behavior in hydrothermal systems that generate economic deposits. The aim of this study ...