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Full-Text Articles in Physical Sciences and Mathematics
Texture And Composition Of An Arid-Climate Weathering Profile And The Link Between Bedrock And Derived Sediment Composition, Kristan Leigh Watkins
Texture And Composition Of An Arid-Climate Weathering Profile And The Link Between Bedrock And Derived Sediment Composition, Kristan Leigh Watkins
Masters Theses
Multiple compositional aspects of Holocene, terrigenous-clastic sediment differ from its source, the underlying Cretaceous Stepladder granodiorite (Mojave Desert, California). Different processes can cause sediments to change in composition from source, including chemical weathering, hydrodynamic sorting during transport, and diagenesis. Sorting and physical processes have previously suggested. To assess the relative contributions of these processes to understand provenance reconstruction, the textures and compositions of an exposed Holocene saprolite weathering profile, grus, and granodiorite bedrock were studied. Fracture density in the weathering profile decreased from ~10% at the top to ~2% at the bottom of the profile in contact with the bedrock. …
Role Of Sorting On The Composition Of Siliciclastic Sediment: Implications For Interpreting Provenance After Limited Transport In An Arid Climate, Forrest Christopher Driscoll
Role Of Sorting On The Composition Of Siliciclastic Sediment: Implications For Interpreting Provenance After Limited Transport In An Arid Climate, Forrest Christopher Driscoll
Masters Theses
This study tested whether transport distances (< 500 m) have the capacity to shape the geochemistry of sediments across multiple grain-size populations due to sorting derived from a single source. In the Stepladder Mountains, Mojave Desert, CA, a < 1 km2 [square kilometers] watershed allows for a controlled study to understand how modern sediments acquire their composition from a single granodioritic source in an arid climate where there is no chemical weathering. Sediments are naturally sorted into distinct grain-size populations, with modes ranging from very fine sand to gravel within a single, alluvial channel. Sediment samples representative of each population were petrographically and geochemically analyzed in order to test the effectiveness of commonly used discrimination diagrams. Sediments became proportionally enriched in plagioclase and biotite and depleted in K-feldspar and quartz with decreasing grain …
Processes Controlling The Composition Of First-Cycle Sediments Deposited In An Arid-Climate, With Implications For Provenance Reconstruction Studies, Aubrey Lynn Modi
Processes Controlling The Composition Of First-Cycle Sediments Deposited In An Arid-Climate, With Implications For Provenance Reconstruction Studies, Aubrey Lynn Modi
Masters Theses
Petrologic analysis of first-cycle clastic sediments derived from a single source in an arid environment provides a means to determine how well they resemble the petrology and geochemistry of their source. The Stepladder Mountains, located in the Mojave Desert of southeastern California, represents a well-controlled location (i.e., arid environment; single, known source; short transport distance) to examine how naturally formed sediments acquire their compositions. Compositional modifications associated with sediment production were resolved through direct examination of the weathered components (regolith, grus, and sediments). Sediment compositions strongly vary by grain size, indicating that, after the source itself, hydrodynamic sorting played the …