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.

Other Description: 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.

摘要：本数据集提供智利北部阿塔卡马沙漠（Atacama Desert）全新世（Holocene）硫酸钙盐的锶同位素比值（87Sr/86Sr）数据，该区域石膏与硬石膏地表堆积分布广泛。本次锶同位素研究的目的在于区分这类矿物中离子的物质来源。采样选取了附着于各类表面的石膏与硬石膏晶体，其伴生的其他沉积物质大概率形成于近数百年间。该沉积物的最终搬运年代尚未被测定，但现有证据表明其年代晚于更新世（Pleistocene）末期气候从干旱向极端干旱转变的关键时期，因此属于全新世。本次共采集28处全新世地表盐类堆积物样品，采样点海拔介于200至2950米之间，纬度范围约为南纬19°30′至21°30′，数据量化了87Sr/86Sr比值随采样点海拔变化的分布特征。

其他说明：Cosentino, N. J.、Jordan, T. E.、Derry, L. A. 与 Morgan, J. P.（2015），《超干旱景观区近期硫酸钙堆积中的87Sr/86Sr比值：智利北部（南纬19.5°-21.5°）的双峰海拔依赖性》，《地球物理学、地球化学、地球系统学》（Geophysics, Geochemistry, Geosystems），第16卷第12期，第4311-4328页。