首页|Chronological constraints on the late Quaternary Beihai wetland deposits in southwestern China and its depositional history linked to hydroclimate change
Chronological constraints on the late Quaternary Beihai wetland deposits in southwestern China and its depositional history linked to hydroclimate change
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NSTL
Elsevier
As documented in several studies, lake sediments in south-western China are important archives to decipher Indian Summer Monsoon (ISM) variability through reconstructions of precipitation and temperature changes, based on multi-proxy analysis of lake sediments. However, lacustrine records on glacial-interglacial timescales in south-western China remain limited because of a lack of reliable long chronologies. In this paper, we provide a 53 ka chronology for the Beihai wetland (core TCBH14) deposits in combination with luminescence and radiocarbon dating of sediments for the upper 13.4 m of a 36.6 m long drill core. The reliability of our chronological framework was verified within two independent chronology sequences and validated by correlations with regional chronostratigraphy. Results suggest that luminescence dating is a feasible method that can provide reliable age controls for lake sediments in south-western China. The depositional history of the Beihai wetland was characterised by alternating lake and wetland facies. Lakes existed at 52-47 ka, 41-32 ka, 26-19 ka and 11-7 ka, whereas a wetland system prevailed at 47-41 ka, 32-26 ka, 19-11 ka, and after similar to 7 ka. The patterns and formation periods of alternate lake-wetland successions are consistent with speleothem delta O-18 and lake delta D-wax records in South Asia, indicating that the sedimentary evolution of the Beihai wetland and other lake-wetland systems in this region are closely linked to ISM-dominated hydroclimate changes. Correlation of sedimentation rates (SRs) of the studied core (TCBH14) with the cores from 11 additional lakes in south-western China suggest that higher SRs occurred during the periods 47-34 ka, 26-19 ka,15-3 ka, and the early Holocene (11-7 ka). In contrast, lower SRs existed during the periods 50-47 ka, 34-26 ka, the last deglaciation (19-15 ka and 12-11 ka), and the middle Holocene (7-5 ka). Thus, we infer that such quasi-synchronous variations of the SRs from these different lakes in south-western China were strongly controlled by the suborbital- or millennial-scale regional hydroclimate, keeping pace with the Northern Hemisphere insolation-induced ISM variability since the last glaciation.
NSTL
Elsevier
