Sr isotopic ratios of Holocene gypsum and anhydrite salt deposits in Atacama Desert, northern Chile

Abstract

This file provides 87Sr/86Sr data for calcium sulfate salts of Holocene age in the Atacama Desert of northern Chile, where gypsum and anhydrite surficial accumulations are widespread. The purpose of the Sr isotopic study is to differentiate among sources of the ions in these minerals. Gypsum/anhydrite was selected for sampling that occurs as crystals adhering to surfaces whose other sedimentary materials are likely to have been deposited in the last few hundred years. The age of last transport of that sediment has not been dated, but evidence indicates it to be younger than the time of major climate change (from arid to hyperarid) at the close of the Pleistocene, hence Holocene. Samples of 28 Holocene surface salt accumulations for locations between 200-2950 meters above sea level and between approximately 19 degrees 30 minutes S latitude and approximately 21 degrees 30 minutes S latitude quantify a variation in 87Sr/86Sr as a function of site altitude.

Abstract

Cosentino, N. J., Jordan, T. E., Derry, L. A., and Morgan, J. P., (2015), "87Sr/86Sr in recent accumulations of calcium sulfate on landscapes of hyperarid settings: A bimodal altitudinal dependence for northern Chile (19.5-21.5°S)." Geophysics, Geochemistry, Geosystems, Volume 16 (12), 4311-4328.