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Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2016

Geochemistry

Louisiana State University

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley: Evaluation Of The Dorag Model And New Implications For Dolomitizing Fluids, John Michael Callen Jan 2016

In Situ Geochemistry Of Middle Ordovician Dolomites Of The Upper Mississippi Valley: Evaluation Of The Dorag Model And New Implications For Dolomitizing Fluids, John Michael Callen

LSU Master's Theses

The dolomitization and diagenetic history of Ordovician carbonates of southern Wisconsin has been studied for over a century. Previous studies attributed dolomitization to various single or multiple diagenetic factors and environments. The goal of the study was to resolve arguments regarding dolomitization models, including Badiozamani’s often cited but recently questioned mixing zone model, using LA-ICP-MS focusing on REE to determine the nature of dolomitizing fluids. Analysis revealed that particulate material incorporated into the dolomite affected the geochemical results of many of the samples. Integrating geochemical data with petrographic evidence for diagenetic history, the studied Decorah Formation dolomites were assigned to …


Metamorphic Conditions Of Aluminous Gneisses In The Sawtooth Metamorphic Complex, Idaho, Usa: Implications For The Middle-Lower Crust, Eleanor Wesley-Anne Smith Jan 2016

Metamorphic Conditions Of Aluminous Gneisses In The Sawtooth Metamorphic Complex, Idaho, Usa: Implications For The Middle-Lower Crust, Eleanor Wesley-Anne Smith

LSU Master's Theses

The Sawtooth Complex (SMC) of central Idaho contains metasedimentary units that elucidate the pressure-temperature conditions and potentially, the evolution of Precambrian crust in the northwestern United States. Petrographic analysis, whole rock geochemistry, and geothermobarometry combined with thermodynamic phase equilibrium modeling record a regional metamorphic pathway for SMC aluminous gneisses characterized by burial to middle-lower crustal levels with at least two deformational events, followed by a retrograde overprint. P-T conditions are generally consistent with the peak assemblage of SMC aluminous gneisses of bt + grt + sil + ilm + zrn + mnz ± pl ± qtz ± kfs ± ap …