Directory

Start date:
Late October
End date:
Early January
Locations:
Olympus Range, Stocking Glacier, McMurdo Dry Valleys
Principle Investigator:
Dr Kate Swanger
Organisation:
Colgate University
Field season overview:
For the 2011-2012 field season, five people will deploy to Antarctica to conduct helicopter-supported fieldwork in the Dry Valleys region. The five-person team will set up remote camps at four locations in the Dry Valleys, remaining at each location for about 10 days. Remote field camp locations will be upper Taylor Valley, central Wright Valley, western Olympus Range and Beacon Valley. A three-person team will be conducting a few helicopter-supported day trips to lower Taylor Valley, Pearse Valley, and Beacon Valley to retrieve data from long-term meteorologic stations originally deployed during 2004 and 2006, as well as to complete retrieval of weathering and meteorological equipment for short-term monitoring sites at the four 2011-2012 field locations.
During the past two decades, exposure dating of bedrock surfaces and glacial deposits has been used throughout Antarctica to expand scientific understanding of past ice-sheet fluctuations and to quantify average long-term weathering rates. Notwithstanding vast improvements in techniques, cosmogenic data sets from Antarctica typically show significant scatter. Therefore, fundamental questions remain regarding the role of polar surface processes (weathering, burial by cold-based glaciers, etc.) in altering cosmogenic inventories in long-exposed rocks. This research project plans to investigate the impact of such processes on the application of cosmogenic exposure dating by combining a multinuclide approach, detailed field experiments, glacial geologic mapping, rock-mechanics studies, and climate modeling. The proposed fieldwork during 2011-12 has two specific goals: 1. Generate an alpine glacier chronology that will serve as a robust record of regional climate variation in the McMurdo Sound region over the past few million years; and 2. Evaluate the effects of weathering, burial, and pre-exposure on exposure ages in polar deserts using the Dry Valleys as a natural laboratory. To achieve these research goals, the field team plans to gather rock samples for exposure dating from multiple alpine moraine systems in Taylor Valley, Wright Valley, western Olympus Range and the Quartermain Range; gather samples from extant glaciers in Taylor and Wright valleys in order to address pre-exposure of rock samples; and perform in-situ experiments and analyses designed to quantify present-day weathering processes and rates in each of the locations. These alpine sequences have been chosen to capture a range of present-day summer climate conditions (that cause variable weathering processes) and hopefully to capture alpine glacier fluctuations that span warmer-than-present time intervals (important analogs for potential future warming). The weathering analyses will address wind erosion, thermal breakdown, salt weathering, frost wedging, and chemical weathering of the common rock types found in the Dry Valleys (granites, sandstones and dolerites). Researchers also plan to gather meteorologic data (temperature, humidity, wind, etc.) from each location for use in rock-weathering models, as well as long-term meteorologic data from New Harbor, Pearse Valley, and Beacon Valley as input for regional climate models. Researchers expect that this study will produce considerable advances in cosmogenic nuclide techniques and sampling strategies that can be applied throughout the Antarctic, advance the understanding of cold-desert processes, and expand the understanding of regional climate change in the Dry Valleys during the past few million years.