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Full-Text Articles in Physical Sciences and Mathematics
Paleoenvironmental Constraints On Pleistocene Ice Sheets From Glacio-Volcanic Deposits In Northeast Iceland, Cameron Essex
Paleoenvironmental Constraints On Pleistocene Ice Sheets From Glacio-Volcanic Deposits In Northeast Iceland, Cameron Essex
Theses and Dissertations
There are indications that the melt-back of glaciers due to climate change can trigger new eruptions for volcanoes and magma reservoirs that rest under ice sheets. The ideal locality on Earth to study volcano-ice interactions is Iceland, an active volcanic island that has been totally covered in previous ice ages. Eruptions under glaciers produce distinctive landforms called tuyas, or table mountains, which can provide an estimate of ice thickness at the time of eruption. One research tool used to investigate ice thickness is volcanic glass, which is formed from rapid cooling of magma, and thus is abundant in the majority …
Authigenic Minerals In Volcaniclastics From An Eastern African Paleolake: A Proxy For Paleoenvironment, Kaitlyn Truss
Authigenic Minerals In Volcaniclastics From An Eastern African Paleolake: A Proxy For Paleoenvironment, Kaitlyn Truss
Theses and Dissertations
Olduvai Gorge exposes the stratigraphy of Paleolake Olduvai, an often saline-alkaline rift lake that records volcanism from the Ngorongoro Volcanic Highlands. In 2014, cores retrieved from the study area revealed new stratigraphy, including the lacustrine Naibor Soit Formation (Fm) and the volcaniclastic Ngorongoro Fm. In the Ngorongoro Fm part of the cores, mineralogy and geochemistry are the best paleoenvironmental proxies, since under saline-alkaline conditions, volcanic glass alters into specific authigenic minerals (e.g., zeolite, feldspar). This study employs X-Ray Diffraction, X-Ray Fluorescence, and Scanning Electron Microscopy to analyze authigenic mineralogy and geochemistry. The lower Ngorongoro Fm experienced the most alteration, with …
Late Paleozoic Climatic Reconstruction Of Western Argentina: Glacial Extent And Deglaciation Of Southwestern Gondwana, Kathryn N. Pauls
Late Paleozoic Climatic Reconstruction Of Western Argentina: Glacial Extent And Deglaciation Of Southwestern Gondwana, Kathryn N. Pauls
Theses and Dissertations
Throughout its history Earth has experienced both icehouse and greenhouse conditions. Shifts and transitions from one end member to the other are driven by numerous driving mechanisms on global, orbital and more local scales. In particular, the late Paleozoic ice age (LPIA) is thought to have been driven by global drivers such as the drift of the Gondwanan continent across the South Pole, fluctuations in atmospheric CO2 concentrations, and Milankovitch cycles. It was also affected by more local and regional drivers such as active tectonism along accretionary margins and changes in atmospheric and oceanic circulation patterns. South American Gondwana provides …