Timing of the neoglacial onset on the North-Eastern Antarctic Peninsula based on lacustrine archive from Lake Anonima, Vega Island

摘要

To understand the complexity of the climate patterns in the Holocene, it is necessary to build detailed chronologies that provide a holistic picture of the individual climate periods occurring in the polar regions. In this regard, here we present a completely new, C-14-dated and synchronised multi-proxy chronology from the Lake Ananima (Vega Island, north-eastern Antarctic Peninsula) that provides a unique insight into the Late Holocene environment. In particular, we aim to interpret the substantial environmental and climatic change between the mid-late Holocene Hypsithermal and Neoglacial periods using various geochemical (total organic carbon, X-ray fluorescence spectroscopy), petrophysical (magnetic susceptibility, laser granulometry) and biological (diatom biostratigraphy) proxies. The termination of the mid-late Holocene Hypsithermal, characterised by overall warmer climate with favourable conditions for biogenic productivity, is followed by the regional-scale Neoglacial period, distinctive by the onset of climate deterioration, decreased siliciclastic input, suppressed biogenic (diatom) productivity and low organic content. Based on a principal component analysis, a multi-proxy record provides the precise timing of the Neoglacial onset in the Lake Anonima record at 2050 (2 sigma: 1990-2130) cal. yrs BP. Applying an adjacent and correlative ice-core (James Ross Island ice cap, r = 0.42), as well as a composite lake sediment (Beak Island, r = 0.49) chronologies, our research provides a refined timing of the Neoglacial onset for the north-eastern Antarctic Peninsula, which is determined to be 2070 +/- 50 yrs. BP. Moreover, the Neoglacial onset was compared with other studies from respective parts of the Antarctic Peninsula.