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Full-Text Articles in Physical Sciences and Mathematics

Geologic Extremes Of The Nw Himalaya: Investigations Of The Himalayan Ultra-High Pressure And Low Temperature Deformation Histories, Dennis Girard Donaldson Jan 2016

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 …


Intracontinental Neotectonics: Case Studies From The Tian Shan Orogen And Kuqa Fold-Thrust Belt, Cindy M. Colón Jan 2016

Intracontinental Neotectonics: Case Studies From The Tian Shan Orogen And Kuqa Fold-Thrust Belt, Cindy M. Colón

LSU Doctoral Dissertations

This dissertation focuses on the kinematic properties of intracontinental deformation during short geologic time scales. Using three case studies this work characterizes active deformation at varying spatial scales within the continental interior of Eurasia. The far-field effect of the Cenozoic Indo-Asia collision is the driving force controlling deformation within the Eurasian continental interior. Active deformation across the intracontinental Tian Shan range challenges the plate tectonic model that proposes crustal deformation is concentrated along plate boundaries. This work further constrains the active kinematics of intracontinental motion that is necessary to understand the dynamics of the Eurasian intracontinental system. The two standing …


Particulate Inorganic Carbon Flux And Sediment Transport Dynamics In Karst: Significance To Landscape Evolution And The Carbon Cycle., Randall Lee Paylor Jan 2016

Particulate Inorganic Carbon Flux And Sediment Transport Dynamics In Karst: Significance To Landscape Evolution And The Carbon Cycle., Randall Lee Paylor

LSU Doctoral Dissertations

Research focused on three areas of karst hydrogeology and sediment transport that have been poorly studied in the past: the role of particulate inorganic carbon transport in calculating carbon sink rates in karst; rapid changes in surface vs. subsurface sediment mixing in karst conduits; and comparison of landscape denudation calculations using dissolved carbonate load vs. total dissolved/sediment load. Carbonate bedrock weathering is a significant component of the atmospheric carbon sink. Particulate inorganic carbon (PIC) in bed and suspended sediment load of karst waters is frequently dismissed as insignificant for calculating denudation and carbon transport/sink rates, but PIC flux has not …


Theory And Utility Of The Three Isotope Fractionation Relationship, Justin Alan Hayles Jan 2016

Theory And Utility Of The Three Isotope Fractionation Relationship, Justin Alan Hayles

LSU Doctoral Dissertations

The field of isotope geochemistry began with the study of oxygen isotope geothermometry, most famously for carbonates. Traditionally oxygen isotope studies are only concerned with the relationship between one rare isotope, oxygen-18, and the common isotope, oxygen-16. In these cases, the abundance of the third stable isotope, oxygen-17 is ignored because for almost all terrestrial processes the 17O-16O relationship roughly scales with the 18O-16O relationship through a fractionation processes and is thought to not provide any new information. However, the discovery of large “mass independent” isotope effects for ozone chemistry has driven a multitude of uses for triple isotope relationships. …


High-Resolution Correlation Using Geophysical And Geochemical Methods On Three Cambrian Drumian Marine Sedimentary Successions In The House Range Embayment, Western Laurentia, Emad I. Elfar Jan 2016

High-Resolution Correlation Using Geophysical And Geochemical Methods On Three Cambrian Drumian Marine Sedimentary Successions In The House Range Embayment, Western Laurentia, Emad I. Elfar

LSU Doctoral Dissertations

The Global boundary Stratotype Section and Point (GSSP) of the base of the Cambrian Drumian Stage was defined at 62 m above the base of the Wheeler formation, at the First Appearance Datum (FAD) of Ptychagnostus atavus (P. atavus), and at 10 meter below the DrumIan Carbon isotope Excursion (DICE) on the Stratotype Ridge in the Drum Mountains western Utah, (Babcock at al., 2004; 2007). Tracing the base of the the Drumian stage to other Middle Cambrian sequences in the House Range Embayment (HRE), a fault-controlled deep-water intrusion into an extensive carbonate platform along the passive margin of western Laurentia, …