Paleoclimatic information recorded in fluid inclusions in halites from Lop Nur, Western China.

ABSTRACT

The homogenization temperature (Th) of primary fluid inclusions in halite can be used for paleoclimate interpretations. Lop Nur, in Central Asia, is an extremely arid zone where large amounts of glauberite were deposited from the late Middle to Late Pleistocene. This deposition was accompanied by formation of large-scale potash-bearing brines. However, quantitative paleotemperature data are still lacking, hindering reconstruction of Quaternary climate conditions and their control over potash formation. We measured the Th of inclusions in halite from the salt field and the top of Upper Pleistocene strata in Lop Nur. The maximum homogenization temperature (Th MAX) of inclusions in halite from the salt field was 41.1 °C, consistent with the maximum ambient temperature (43.4 °C) in the same period. The Th MAX of inclusions in halite from the Upper Pleistocene strata ranged from 35.6 °C to 43 °C, where maximum air temperatures may have reached 37.9 °C to 45.3 °C. The results show that a hot and arid climate prevailed in Lop Nur at the end of the Late Pleistocene. Furthermore, changes of the brine chemical composition due to supply variations instead of climate change, may have caused glauberite deposition to cease at the end of the Late Pleistocene.