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Full-Text Articles in Geology

A High-Resolution Mid-Pleistocene Temperature Record From Arctic Lake El'gygytgyn: A 50 Kyr Super Interglacial From Mis 33 To Mis 31?, Gregory De Wet, Isla S. Castañeda, Robert M. Deconto, Julie Brigham-Grette Feb 2016

A High-Resolution Mid-Pleistocene Temperature Record From Arctic Lake El'gygytgyn: A 50 Kyr Super Interglacial From Mis 33 To Mis 31?, Gregory De Wet, Isla S. Castañeda, Robert M. Deconto, Julie Brigham-Grette

Geosciences: Faculty Publications

Previous periods of extreme warmth in Earth's history are of great interest in light of current and predicted anthropogenic warming. Numerous so called "super interglacial" intervals, with summer temperatures significantly warmer than today, have been identified in the 3.6 million year (Ma) sediment record from Lake El'gygytgyn, northeast Russia. To date, however, a high-resolution paleotemperature reconstruction from any of these super interglacials is lacking. Here we present a paleotemperature reconstruction based on branched glycerol dialkyl glycerol tetraethers (brGDGTs) from Marine Isotope Stages (MIS) 35 to MIS 29, including super interglacial MIS 31. To investigate this period in detail, samples were …


Modern Foraminiferal Assemblages Of The Denmark Strait, Laura Larocca Jan 2016

Modern Foraminiferal Assemblages Of The Denmark Strait, Laura Larocca

Dissertations and Theses

Foraminifera occupy a geological range from the early Cambrian to the present day. Their well preserved shells, high relative abundance, and short response time to changing environmental conditions make foraminifera ideal proxies for environmental change. Benthic foraminifera are a valuable but poorly understood paleobiological proxy for the reconstruction of environmental conditions on continental shelves occupied by arctic and subarctic waters. This study identifies, examines, and quantifies calcareous benthic foraminiferal faunas from a sediment core taken from the Denmark Strait. Our analysis of three-thousand individuals from ten discrete samples aim to provide a better understanding of the modern patterns of foraminiferal …


Preservation And Sediment Cycling Beneath "Ghost Glaciers": How Cold-Based Ice Dictates Arctic Landscape Evolution, Lee Corbett Jan 2016

Preservation And Sediment Cycling Beneath "Ghost Glaciers": How Cold-Based Ice Dictates Arctic Landscape Evolution, Lee Corbett

Graduate College Dissertations and Theses

Constraining past episodes of climate change and glacial response is critical for understanding future impacts of climate change, especially in the high latitudes where warming is expected to be rapid and most of Earth's glaciers exist. Many studies of past glacier size utilize rare isotopes called cosmogenic nuclides to perform surface exposure dating. Since most areas of Earth's surface that were previously glaciated were covered by erosive ice, which stripped away pre-existing cosmogenic nuclides, surface exposure dating yields the timing of the most recent deglaciation. However, in some high latitude areas where glacial ice is cold-based and non-erosive (so-called 'ghost …