2017-2018 USAP Field Season
U-series comminution age constraints on Taylor Valley erosion
Dr. Terrence Blackburn
University of California Santa Cruz
Supporting Stations: McMurdo Station
Two competing theories explain the timing of glacial incision in the Taylor Valley, indicating that glacial incision occurred either under the polar conditions of the last few million years, or that incision happened prior to the onset of persistent polar conditions. Researchers seek to establish the timing of silt production and subglacial erosion within the valley and finally clarify the evolution of its present glacial landscape. They will sample Quaternary moraines within the Taylor Valley, as well as the modern basal ice layer of Taylor Glacier and deposits of the Ross Sea Drift at the mouth of the Taylor Valley near McMurdo Sound. They will use U-series comminution dating to place time constraints on the production of fine particles deposited by past glacial advancement, which will shed light on when the topography of the Taylor Valley was generated.
Field Season Overview
Three participants will work out of fixed field camps at Lake Bonney, Lake Hoare, and Lake Fryxell in the Taylor Valley over approximately 18 days during October and November. Co-PI Dr. Slawomir Tulaczyk is deploying under his other project (1644187/C-516-M) but will start with G-167 then transfer to C-516 in November. G-167 will deploy one of their three participants slightly later so that they only have three participants in the field at a time.
The group will sample along transects covering areas that represent various drift deposits, including: (1) Taylor I-II basal ice around the terminus of Taylor and Rhone Glaciers (outside of ASPA 172); (2) higher elevations near West Lake Bonney; (3) South of East Lake Bonney; (4) Ross Sea Drift young; and (5) Ross Sea Drift old. Using shovels, trowels, picks, and hammers, they will dig into drift deposits to access till that is uncontaminated by surface dust. They will remove several kilograms of material from different deposit types and ages along each transect. They will also sample ‘dirty’ basal ice from Taylor and Canada Glaciers.
Sampling areas are located within one to twelve miles of fixed camps, and the group will travel on foot or use helicopter day trips to access their sites. Helicopter support will also be required for camp put-in, two camp moves, and final camp pull-out.
Deploying Team Members