TY - JOUR
T1 - Sediment geochemistry of Lake Daihai, north-central China
T2 - Implications for catchment weathering and climate change during the Holocene
AU - Sun, Qianli
AU - Wang, Sumin
AU - Zhou, Jie
AU - Chen, Zhongyuan
AU - Shen, Ji
AU - Xie, Xiuping
AU - Wu, Feng
AU - Chen, Peng
PY - 2010
Y1 - 2010
N2 - A 12.87-m-long sediment core was retrieved from closed-basin Lake Daihai in the monsoon-arid transition zone of north-central China. Oxides of major elements and their ratios normalized to Al in the AMS-14C-dated core were employed to evaluate chemical weathering intensity (CWI) in the lake drainage basin, which reflects hydrothermal conditions in the study area. Lower CWI periods occurred prior to 14. 5 ka BP, and during the intervals ca. 11.7-10.3, 3.5-3.2, 2.6-1.7 ka BP, and 1.2-0 ka BP, indicating relatively low temperatures and moisture availability. Greater CWI during the intervening periods ca. 14.5-11.7, 10.3-9.0, 3.2-2.6, and 1.7-1.2 ka BP, with the maximum CWI at ca. 6.7-3.5 ka BP, imply ameliorated hydrothermal conditions in the lake basin, i. e. higher temperatures and precipitation. Exceptionally low CWI, associated with high CaO/MgO ratio during ca. 9.0-6.7 ka BP, suggests higher evaporation rates in the area under warmer temperature. Overall, CWI displays in-phase variations with changes in organic matter (TOC, TN), carbonate (CaCO3) and pollen assemblages, all of which are related to variations in monsoon effective precipitation. High CWI indicates strong monsoon-induced precipitation, whereas low CWI reflects a weak precipitation regime. The optimum hydrothermal status, recorded by the strongest CWI and maximum monsoon effective precipitation during ca. 6.7-3.5 ka BP defines the Holocene climate optimum (HCO) in the Lake Daihai region. These results indicate that the HCO prevails after the early Holocene in the monsoon-arid transition zone of north-central China. Temperature and precipitation variations during most of the Holocene, inferred from the lake sediments, are due largely to insolation forcing. Dry but warm conditions ca. 9.0-6.7 ka BP, however, probably reflect the complex interactions between insolation and geography (e. g. altitude and local topography).
AB - A 12.87-m-long sediment core was retrieved from closed-basin Lake Daihai in the monsoon-arid transition zone of north-central China. Oxides of major elements and their ratios normalized to Al in the AMS-14C-dated core were employed to evaluate chemical weathering intensity (CWI) in the lake drainage basin, which reflects hydrothermal conditions in the study area. Lower CWI periods occurred prior to 14. 5 ka BP, and during the intervals ca. 11.7-10.3, 3.5-3.2, 2.6-1.7 ka BP, and 1.2-0 ka BP, indicating relatively low temperatures and moisture availability. Greater CWI during the intervening periods ca. 14.5-11.7, 10.3-9.0, 3.2-2.6, and 1.7-1.2 ka BP, with the maximum CWI at ca. 6.7-3.5 ka BP, imply ameliorated hydrothermal conditions in the lake basin, i. e. higher temperatures and precipitation. Exceptionally low CWI, associated with high CaO/MgO ratio during ca. 9.0-6.7 ka BP, suggests higher evaporation rates in the area under warmer temperature. Overall, CWI displays in-phase variations with changes in organic matter (TOC, TN), carbonate (CaCO3) and pollen assemblages, all of which are related to variations in monsoon effective precipitation. High CWI indicates strong monsoon-induced precipitation, whereas low CWI reflects a weak precipitation regime. The optimum hydrothermal status, recorded by the strongest CWI and maximum monsoon effective precipitation during ca. 6.7-3.5 ka BP defines the Holocene climate optimum (HCO) in the Lake Daihai region. These results indicate that the HCO prevails after the early Holocene in the monsoon-arid transition zone of north-central China. Temperature and precipitation variations during most of the Holocene, inferred from the lake sediments, are due largely to insolation forcing. Dry but warm conditions ca. 9.0-6.7 ka BP, however, probably reflect the complex interactions between insolation and geography (e. g. altitude and local topography).
KW - Chemical weathering
KW - Effective precipitation
KW - Hydrothermal status
KW - Lake Daihai
KW - Major elements
UR - https://www.scopus.com/pages/publications/77949774706
U2 - 10.1007/s10933-009-9315-x
DO - 10.1007/s10933-009-9315-x
M3 - 文章
AN - SCOPUS:77949774706
SN - 0921-2728
VL - 43
SP - 75
EP - 87
JO - Journal of Paleolimnology
JF - Journal of Paleolimnology
IS - 1
ER -
