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Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
The Twiggs Clay: Mineralogy, Origin, And Industrial Properties Of An Upper Eocene Opaline Claystone In The Coastal Plain Province Of Georgia, U.S., Lori G. Eversull
The Twiggs Clay: Mineralogy, Origin, And Industrial Properties Of An Upper Eocene Opaline Claystone In The Coastal Plain Province Of Georgia, U.S., Lori G. Eversull
LSU Doctoral Dissertations
The Twiggs Clay is an upper Eocene claystone found as discontinuous deposits downdip of the Fall Line in the Coastal Plain Province of eastern and central Georgia. A distinctive facies of the Twiggs is found in two lenses near the town of Wrens. The nature, origin, and potential commercial application of this resource are examined. Four strata and two mineralogic assemblages are recognized in the Wrens deposit. The lower three strata are near white in color and very low in density. These strata are mineralogically similar and are composed predominantly of disordered silica and smectite. The smectite is dioctahedral, and …
The Stable Isotope Stratigraphy And Paleosols Of North America's Most Southern Exposure Of Late Paleocene/Early Eocene Fossiliferous Continental Deposits: Documenting The Initial Eocene Thermal Maximum In Big Bend National Park, Texas, Paul David White
LSU Doctoral Dissertations
A chemostratigraphic section across the Paleocene/Eocene boundary, using the stable isotopes of carbon and oxygen, has been developed for North America's most southern exposure of early Paleogene continental deposits in which the boundary is constrained by fossil mammals. A negative carbon excursion has been identified within C24r. The range in d13C values is from -8.1 to -13.2‰. Until the development of the chemostratigraphic section it was uncertain if the earliest Eocene was recorded in Big Bend. An early Wasatchian (Wa1) fossil site occurs stratigraphically higher than the carbon excursion and has yielded the stratigraphically lowest Hyracotherium in the …
Komatiites Of The Weltevreden Formation, Barberton Greenstone Belt, South Africa: Implications For The Chemistry And Temperature Of The Archean Mantle, Keena Kareem
LSU Doctoral Dissertations
The komatiites of the 3.29 Ga Weltevreden Formation, Barberton Greenstone Belt, South Africa represent extremely magnesian lavas derived from the Archean mantle. Three related papers are presented on aspects of the temperature and composition of the Archean mantle, and surface alteration processes. Petrographical and geochemical analyses confirm that olivines from the komatiites retain much of their original igneous character, containing fresh olivines, pyroxenes, and chromites. The olivines from the Weltevreden Formation are extremely magnesian, with Fo contents up to 95.6. Primitive mantle normalized Gd/Yb values near 1, and Al2O3/TiO3 values of 26-33 for these rocks …
Carbonate Records Of Submarine Hydrocarbon Venting: Northern Gulf Of Mexico, Matthew S. Hackworth
Carbonate Records Of Submarine Hydrocarbon Venting: Northern Gulf Of Mexico, Matthew S. Hackworth
LSU Doctoral Dissertations
Hydrocarbon seep sediments are examined from 3 sites in the Gulf of Mexico (Green Canyon Lease Blocks 232, 185, and 272) to relate the effects of gas hydrates and hydrocarbons on microbial process, pore fluid chemistry, and the processes of authigenic carbonate formation. Hydrocarbon-fueled microbial reactions result in pore fluids with lowered SO42- (all consumed by –10 cm) and enrichments in H2S, alkalinity, and DIC (up to 20 mmol, 30 meq/L, and 18 mmol/L, respectively) which promote carbonate formation. Pore fluid d13CDIC (PDB) is influenced by thermogenic hydrocarbons and crude oil in GC …