High‐Resolution Elemental Record From the Holocene Sediments of an Alpine Lake in the Central Altai Mountains: Implications for Arctic Sea‐Ice Variations

Abstract

Abstract It is well known that Arctic sea ice and Arctic amplification have played an important role in recent climate change in middle to high latitudes of the Northern Hemisphere. We present a high‐resolution elemental data set, spanning the past 9,000 years, obtained using in‐situ synchrotron radiation X‐ray fluorescence measurements of a lake sediment core from Lake Shuang in the Altai Mountains. Based on calibration against the local instrumental climatic record, the Rb/Sr ratio of the sediments is interpreted as an indicator of weathering intensity, which is related to precipitation and temperature variations. There is very little bromine in the granites and moyites in the catchment of Lake Shuang, and the sedimentary Br is derived primarily from wet deposition originating from precipitation and enriched by biogenic processes in this open lake system. The Br variation is positively correlated with local precipitation. The Rb/Sr and Br time series show distinct decadal‐scale to millennial‐scale cycles that are similar to those of Arctic sea‐ice variations, which implies the important role of Artic sea ice in modulating environmental change at Lake Shuang. Our results support a previous suggestion that sea ice loss would cause an increase in atmospheric water vapor content in the Arctic, resulting in the frequent incursion of cold air masses from the Arctic into middle latitudes, and leading to increased snow cover and precipitation, and vice versa.

Keywords

• synchrotron radiation X‐ray fluorescence
• Altai Mountains
• Rb/Sr ratio
• bromine
• cyclic climate variations
• Arctic sea ice