GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 207-5
Presentation Time: 2:35 PM


GRANT, Andrew J., Earth & Environmental Sciences, Vanderbilt University, 2301 Vanderbilt Place, Nashville, TN 37235, MORGAN, Daniel, Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37235, PUTKONEN, Jaakko, Harold Hamm School of Geology and Geological Engineering, University of North Dakota, 81 Cornell St, STOP 8358, Grand Forks, ND 58202-8358 and BALCO, Greg, Berkeley Geochronology Center, 2455 Ridge Road, Berkeley, CA 94709

The purpose of this project is to apply a new soil chronology method in a new field location. We measured the concentrations of salts in the middle and upper soil horizons of glacial tills in Ong Valley of the Central Transantarctic Mountains, Antarctica. A linear accumulation rate of these salts is anticipated, as their origin is predominately atmospheric with transport to sediment being constant over relative timescales. Previous cosmogenic nuclide exposure age analysis demonstrates the existence of three distinct glacial tills along the valley floor, forming as deposited regolith from the sublimation of the Argosy Glacier at the mouth of the valley. These tills range from 11 ka to 2 Ma. One gram of the silt fraction (<63 micrometers) from each soil pit was dissolved in ultrapure water, and then analyzed for water-soluble salts. The dissolved sample was analyzed for Na, K, Ca, Mg, S, and B on an ICP-OES; and for Cl-, SO42-, NO3-, NO2-, Fl-, PO43-, and Br- on an ion chromatograph. We will analyze all measured salt concentrations for distance from the moraine, compare the salt data to previously determined exposure ages, and compare findings for the upper and middle soil horizons. Preliminary findings suggest a trend of higher salt abundance in the oldest till, with lower abundance in the middle till, and lowest in the youngest till. Furthermore, our findings suggest higher salt concentrations within the upper, shallow soil horizon (c. 5-10cm) and lower concentrations within deeper horizons (c. 20-30 cm).