In the mid-latitude regions of the Asian continent, Zhuye Lake is located in the northwest margin of the Asian monsoon, where the modem climate is affected by the Asian monsoon and Westerlies. In this study, we invest...In the mid-latitude regions of the Asian continent, Zhuye Lake is located in the northwest margin of the Asian monsoon, where the modem climate is affected by the Asian monsoon and Westerlies. In this study, we investi- gated the absolutely dated Holocene records in Zhuye Lake for detecting the Holocene climate cycles. Totally, 14 14C dates and 6 optically simulated luminescence （OSL） dates are obtained from the QTH01 and QTH02 sections. The proxies of grain-size, total organic carbon content （TOC）, C/N and 813C are used for wavelet analysis, and the results show obvious -256, -512 and -1024-year climate cycles, which are consistent with the Holocene millennial and cen- tennial scale climate cycles in the typical Asian summer monsoon domain. In different parts of the Zhuye Lake, the Holocene sediments show variable climate cycles that are affected by the lake basin topography. In the Zhuye Lake, the Holocene climate cycles are mainly correlated with the solar-related Asian summer monsoon variability and the North Atlantic ice-rafting events.展开更多
High-resolution oxygen isotope records over the last 2249 ka (MIS 1-86) have been obtained from cores of the upper section (105.08 m) at ODP Site 1143 (water depth of 2772 m)drilled in the Nansha area, southern South ...High-resolution oxygen isotope records over the last 2249 ka (MIS 1-86) have been obtained from cores of the upper section (105.08 m) at ODP Site 1143 (water depth of 2772 m)drilled in the Nansha area, southern South China Sea. The sampling resolution is at about 2 ka intervals, resulting in one of the best oxygen isotope records over the global ocean. The oxygen isotope curves, displaying details in the Pleistocene glacial cycles, have revealed a nearly 300 ka long stage of transition from a predominant 40 ka to 100 ka periodicity. Therefore, the 'Mid-Pleistocene Revolution' should be considered as a process of transition rather than an abrupt change. Within the 100 ka glacial cycles, the changes in tropical sea surface water were found to lead those in high-latitude ice sheet. Our comparisons show that the ice sheet expansion and the glacial stage extension in the Northern Hemisphere with the 100 ka cycles must have been driven not by ice sheet itself, but by processes outside the high latitudes of the Northern Hemisphere.展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 41001116)Fundamental Research Funds for the Central Universities (No. LZUJBKY-2010-99)
文摘In the mid-latitude regions of the Asian continent, Zhuye Lake is located in the northwest margin of the Asian monsoon, where the modem climate is affected by the Asian monsoon and Westerlies. In this study, we investi- gated the absolutely dated Holocene records in Zhuye Lake for detecting the Holocene climate cycles. Totally, 14 14C dates and 6 optically simulated luminescence （OSL） dates are obtained from the QTH01 and QTH02 sections. The proxies of grain-size, total organic carbon content （TOC）, C/N and 813C are used for wavelet analysis, and the results show obvious -256, -512 and -1024-year climate cycles, which are consistent with the Holocene millennial and cen- tennial scale climate cycles in the typical Asian summer monsoon domain. In different parts of the Zhuye Lake, the Holocene sediments show variable climate cycles that are affected by the lake basin topography. In the Zhuye Lake, the Holocene climate cycles are mainly correlated with the solar-related Asian summer monsoon variability and the North Atlantic ice-rafting events.
基金the National Natural Science Foundation of China (Grant No. 49999560) and NKBRSF Project (Grant No. 2000078500).
文摘High-resolution oxygen isotope records over the last 2249 ka (MIS 1-86) have been obtained from cores of the upper section (105.08 m) at ODP Site 1143 (water depth of 2772 m)drilled in the Nansha area, southern South China Sea. The sampling resolution is at about 2 ka intervals, resulting in one of the best oxygen isotope records over the global ocean. The oxygen isotope curves, displaying details in the Pleistocene glacial cycles, have revealed a nearly 300 ka long stage of transition from a predominant 40 ka to 100 ka periodicity. Therefore, the 'Mid-Pleistocene Revolution' should be considered as a process of transition rather than an abrupt change. Within the 100 ka glacial cycles, the changes in tropical sea surface water were found to lead those in high-latitude ice sheet. Our comparisons show that the ice sheet expansion and the glacial stage extension in the Northern Hemisphere with the 100 ka cycles must have been driven not by ice sheet itself, but by processes outside the high latitudes of the Northern Hemisphere.
