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Full-Text Articles in Physical Sciences and Mathematics
Late Miocene Unroofing Of The Inner Lesser Himalaya Recorded In The Nw Himalaya Foreland Basin, Elise Marie Exnicios
Late Miocene Unroofing Of The Inner Lesser Himalaya Recorded In The Nw Himalaya Foreland Basin, Elise Marie Exnicios
LSU Master's Theses
Testing models that link climate and solid Earth tectonics requires independent erosional, structural and climatic histories. Two well preserved stratigraphic sections of the Himalayan foreland basin are exposed in NW India. The Jawalamukhi (13–5 Ma) and Joginder Nagar sections (21–13 Ma) are dated by magnetostratigraphy and span a period of significant climate change and tectonic evolution. We use detrital zircon U-Pb dating and apatite fission track analyses to reconstruct changes in the patterns of erosion and exhumation in this area from the Early Miocene to Pliocene. The provenance of the foreland sediments shows that since at least ~21 Ma the …
The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory
The Modern Mississippi: Provenance Indicators And Human Impact, Brittney Anne Gregory
LSU Doctoral Dissertations
Given the significant degree to which the modern Mississippi River and its tributaries have been altered through dams, levees, and diversions, it is important to understand how sediment is transported from source to sink. The objective of this dissertation is to explore how the modern Mississippi River transports sediment from its tributaries to its delta using three independent proxies. Provenance indicators have traditionally been an effective way with which to characterize sediment transport in large river systems. First, detrital U-Pb zircon dating is used to investigate modern flux and possible anthropogenic influences on coarse-grained sediment within the modern Mississippi River. …
Geologic Extremes Of The Nw Himalaya: Investigations Of The Himalayan Ultra-High Pressure And Low Temperature Deformation Histories, Dennis Girard Donaldson
Geologic Extremes Of The Nw Himalaya: Investigations Of The Himalayan Ultra-High Pressure And Low Temperature Deformation Histories, Dennis Girard Donaldson
LSU Doctoral Dissertations
This dissertation focuses on two extremes of orogenic development in the Himalaya: the timing of early ultra-high pressure related tectonics and the subsequent emplacement of the high grade Greater Himalayan Crystallines. The Himalayan orogeny is one of if not the best example of ongoing collisional systems, marked by the ongoing convergence of the Indian and Asian continents. The presence of coesite in the Tso Morari complex respresents subduction of the Indian continental crust to ultrahigh-pressure (UHP) conditions. However, the timing of UHP metamorphism is debated, creating an uncertainty in the calculation of subduction and exhumation rates. Petrologic and geochronologic analyses …
Archean Geodynamic Conditions Using P-T Constraints Of The East Pilbara Craton Ttgs, Andrew Kody Webb
Archean Geodynamic Conditions Using P-T Constraints Of The East Pilbara Craton Ttgs, Andrew Kody Webb
LSU Master's Theses
We know very little about the tectonic setting present during the Hadean, but based on studies of surviving Hadean zircons, we know that a Hadean protocrust must have been established by at least 4.4 Ga (Kemp et al. 2010), and it must have also been able to accommodate minimum melt conditions (Harrison 2005). Tectonic models for Earth during the Hadean and Archean follow two trends: uniformitarianism and non-uniformitarianism. Uniformitarian models (following the famed geological concept that the present is the key to the past) argue that Hadean zircons and Archean rocks formed via processes akin to modern-style oceanic crust production …
U-Pb Geochronology Of Detrital Zircon In Quartzites Of The Sawtooth Metamorphic Complex, Sawtooth Range, Idaho, Usa, Philip Gerard Bergeron
U-Pb Geochronology Of Detrital Zircon In Quartzites Of The Sawtooth Metamorphic Complex, Sawtooth Range, Idaho, Usa, Philip Gerard Bergeron
LSU Master's Theses
In southwest Laurentia, the Paleoproterozoic Selway terrane has been proposed to extend as basement from the Wyoming Province to the Proterozoic rifted margin of Laurentia primarily based on limited exposures. The Sawtooth Metamorphic Complex (SMC), Idaho, a series of high-grade metasupracrustal rocks lies within the proposed region of the Selway terrane and may represent remnants of this terrane. Alternatively, it may represent another basement terrane of cratonic North America. To test the hypothesis that the SMC belongs to the Selway terrane, detrital zircon U/Pb ages of five quartzite samples were analyzed by LA-ICP-MS to establish age, possible provenance, and age …