Latitudinal Expansion of the Holocene Optimum in the East Asian Monsoon Region

Thursday, 18 December 2014: 11:50 AM
Xin Zhou1, Liguang Sun1, Tao Zhan2, Wen Huang1, Xinying Zhou3, Qingzhen Hao4, Xiaoqing He1, Chao Zhao3, Jun Zhang2, Yansong Qiao5, Junyi Ge6, Pei Yan1, Da Shao1, Zhuding Chu1 and Wenqing Yang7, (1)USTC University of Science and Technology of China, Hefei, China, (2)The Second Hydrogeology and Engineering Geology Prospecting Institute of Heilongjiang Province, Heilongjiang, China, (3)Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China, (4)Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China, (5)Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing, China, (6)CAS Chinese Academy of Sciences, Beijng, China, (7)USTC University of Science and Technology of China, Institute of Polar Environment, School of Earth and Space Sciences, Hefei, China
With increasingly abundant high resolution and high precision records of East Asian monsoon, its spatial and temporal dynamics during the Holocene have been extensively studied. However, partly due to the lack of records in high latitude areas and the age uncertainties, these studies characterized a wide range of spatial-temporal patterns of Holocene Optimum (HO). We reconstructed a 14,000-year record of vegetation using sediments from a crater lake in Northeast China. Analyses of the vegetation time series show that HO began around 6,000 a BP in Northeast China, significantly later than generally recognized. By comparison with Holocene records of vegetation in other regions of the East Asia, we found a marked northward shift of initial time of HO from 10,600 a BP in South China to 6,000 a BP in Northeast China, which appeared to be forced by the shrinkage of the northern hemisphere ice-sheet (NHIS) during early to mid Holocene. Finally, we fitted a regression model of initial HO time on latitude, which allows us to make prediction of initial HO time based on their geographical locations. This study reveals a strong relationship between latitude and initial HO times and provides a window towards understanding the joint forcing of high and low latitude factors on regional climate.