Climatic variability during the last interglacial inferred from geochemical proxies in the Lake El'gygytgyn sediment record

Summary, in English

The Last Interglacial Period (LIP) is often regarded as a good analogue for potential climatic conditions under predicted global warming scenarios. Despite this, there is still debate over the nature, duration and frequency of climatic changes during this period. One particularly contentious issue has been the apparent evidence of climatic instability identified in many marine cores but seemingly lacking from many terrestrial archives, especially within the Arctic, a key region for global climate change research. In this paper, geochemical records from Lake El'gygytgyn, north-eastern Russia, are used to infer past climatic changes during the LIP from within the high Arctic. With a sampling resolution of ~ 20–~ 90 years, these records offer the potential for detailed, high-resolution palaeoclimate reconstruction. This study shows that the LIP commenced in central Chukotka ~ 129 thousand years ago (ka), with the warmest climatic conditions occurring between ~ 128 and 127 ka before being interrupted by a short-lived cold reversal. Mild climatic conditions then persisted until ~ 122 ka when a marked reduction in the sedimentation rate suggests a decrease in precipitation. A further climatic deterioration at ~ 118 ka marks the return to glacial conditions. This study highlights the value of incorporating several geochemical proxies when inferring past climatic conditions, thus providing the potential to identify signals related to environmental change within the catchment. We also demonstrate the importance of considering how changes in sedimentation rate influence proxy records, in order to develop robust palaeoenvironmental reconstructions.