![]() ![]() ![]() Preparation protocols, independently checked using various methods, were selected with minimal mineralogical impact and OSL sensitivity considerations in mind. The sample site was selected for a case study on OSL dating techniques because previous work has constrained the maximum age of post-Lake Bonneville dune formation (~12 ka BP). Relatively homogenous eolian gypsum sand grain samples with grain sizes ranging from 250 μm from two adjacent paleodunes (KNP-A and KNP-B) and one coppice dune (CD-5) were used to determine best preparation practices and identify if punctuated climatic events during the Holocene could be detected using gypsum. The focus of this study seeks to resolve discrepancies observed in the small body of literature on gypsum as an OSL chronometer. Sampling strategy can be quickly determined for dunes that are exposed on all sides. Additionally, gypsum sand grains are accessible to researchers in geomorphic features like unconsolidated to semi-consolidated dunes, making them easier to sample for OSL analyses than gypsum or quartz found in an outcrop. Gypsum has also been observed at several hundred meters water depth in the alkaline environment of the Arctic Ocean. Knowledge of gypsum behavior is of particular interest, as it is found in both lacustrine and marine environments and is typically less soluble than other evaporites found in both settings, such as sodium chloride. Multiple experiments were undertaken to assess the effectiveness of mineral isolation and etching. To accomplish this pursuit, systematic research of gypsum preparation protocols were required. Using OSL we aimed to identify the ages of punctuated climatic events that are linked to deposition of the gypsum rich dunes found in the study area. Sedimentologists often rely on proxies to understand geologic timescales, OSL may eliminate that need in environments with gypsum. This study examines eolian samples from post-Lake Bonneville gypsum dunes in Knolls, UT, primarily to determine suitability of optically stimulated luminescence (OSL) dating protocols for gypsum geochronology. ![]()
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