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Full-Text Articles in Earth Sciences
Effects Of Terrestrial Weathering On Rare Earth Element Concentrations And Sulfur Isotopic Signatures Of Carbonaceous And Ordinary Chondrites, Ruby Virginia Patterson
Effects Of Terrestrial Weathering On Rare Earth Element Concentrations And Sulfur Isotopic Signatures Of Carbonaceous And Ordinary Chondrites, Ruby Virginia Patterson
Graduate Theses and Dissertations
Understanding the effects of weathering of chondrites is essential to gaining accurate and useful information about the formation of our solar system, as well as a more detailed account of the mobilization of chondritic compounds when they encounter terrestrial conditions. Elemental concentrations and stable isotope analyses of chondrites, considered to be the most primordial material in the solar system, are two tools which help unlock the weathering patterns of these specimens when they enter the earth system. However, it is not currently known exactly how time spent in the field alters rare earth element (REE) concentration or δ34S signatures within …
An Isotopic Assessment Of Late Prehistoric Interregional Warfare In The Southcentral Us, John R. Samuelsen
An Isotopic Assessment Of Late Prehistoric Interregional Warfare In The Southcentral Us, John R. Samuelsen
Graduate Theses and Dissertations
Skull burials are found all over the world. The cause of such ancient Native Americans deposits often lead to disagreement among scholars torn between warfare and ancestor veneration. One skull-and-mandible deposit, representing at least 352 people (A.D. 1253-1399), was uncovered at the Crenshaw site, a multiple-mound Caddo ceremonial center in southwest Arkansas. Most previous research suggested they were victims of interregional warfare from the Southern Plains or Mississippi Valley. One previous study hypothesized that this was a Caddo burial practice which expanded during the Middle Caddo period (A.D. 1200-1500) due to the adoption of maize as a staple and a …
Comparative Geochemical Analysis Of Ordovician And Mississippian Cherts In Relation To The Northern Arkansas And The Tri-State Mississippi Valley-Type Ore Districts, Jonathan T. Chick
Comparative Geochemical Analysis Of Ordovician And Mississippian Cherts In Relation To The Northern Arkansas And The Tri-State Mississippi Valley-Type Ore Districts, Jonathan T. Chick
Graduate Theses and Dissertations
It has been hypothesized that Ordovician, Mississippian, and younger carbonate and clastic formations found within the Ouachita Basin of west-central Arkansas and northward onto the Ozark Dome have experienced interaction with hydrothermal fluids due to tectonic forces produced by the Ouachita Orogeny. Lead (Pb) isotope analyses and resulting values produced through previous and concurrent geochemical studies of several formations indicate that the Mississippi Valley-type (MVT) ores were produced from a mixing and cooling of these sedimentary basinal brines by meteoric or connate waters. Reduction of sulfate to sulfide is one of the possible mechanisms by which MVT ore precipitation may …