The Huguang maar lake—a high-resolution record of palaeoenvironmental and palaeoclimatic changes over the last 78,000 years from South China

摘要

A series of seven piston cores from the Huguang maar lake situated near the South China Sea coastline provides insight into regional palaeoenvironmental and palaeoclimatic changes in southern China over the last 78,000 years. The data set comprises a high-resolution record of magnetic susceptibility, dry density and water content, total organic carbon and inorganic carbon, total nitrogen, biogenic silica (BSiO_2), and palynological results. The time scale was developed by AMS ~(14)C dating of 17 terrestrial plant macro-fossils. During the Last Glacial the Huguang record is characterised by an alternation of more temperate and humid periods (from 78 to 58 and 48 to 40.5 ka BP) and periods with predominance of grassland vegetation and possibly lowered lake level (from 58 to 48 and ca 40.5 to 15 ka BP). The Huguang data have been compared to regional marine and terrestrial records in order to discuss variability of the South-East Asian monsoon system. For most of the Last Glacial period the Huguang proxies do not exhibit marked millennial-scale variability as known from some long SE Asian and many North Atlantic records. This picture changes at about 15 cal ka BP when the Huguang and Greenland records appear to correlate well. A short climatic reversal which is assumed to reflect a Younger Dry as-type event is well recorded in the Huguang record. During the Holocene the Huguang multi-proxy data show a much higher variability than during the Last Glacial stage probably reflecting, at least for the early mid-Holocene, fluctuations in monsoon activity. However, the last 4000 years of the sediment record are clearly influenced by enhanced human activity and thus difficult to interpret in terms of palaeoclimate change.