Hydroclimatic variations in southeastern China during the 4.2 ka event reflected by stalagmite records
Hydroclimatic variations in southeastern China during the 4.2 ka event reflected by stalagmite records
复制标题
石笋记录反映的4.2·ka事件期间中国东南部水文气候变化
DOI：
10.5194/cp-14-1805-2018
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发表时间：
2018-11-27
影响因子：
4.3
通讯作者：
Tan, Liangcheng
中科院分区：
文献类型：
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作者：
Zhang, Haiwei;Cheng, Hai;Tan, Liangcheng
尽管中国地区几种新石器时代文化的崩溃被认为与4.2ka BP事件(4.23.9ka BP)期间的气候突变有关，但这一事件的发生时间和性质以及中国南北降水的空间分布仍然存在争议。这一事件在中国东南部的水气候仍然鲜为人知，除了来自长江下游的一些已发表的记录。本文利用中国东南部江西神农洞的石笋，记录了5.3~3.57ka BP的季风降水的高分辨率记录。O-18三角洲和C-13三角洲的相干变化表明，中国地区的气候在5.3~4.5ka BP之间以湿气候为主，在4.5~3.57ka BP之间以干气候为主，中间有一段湿润区间(4.2~3.9ka BP)。与中国季风记录的对比表明，4.2ka BP事件期间，中国北部夏季风降水减少，而中国南部夏季风降水增加。我们认为，受大西洋经向翻转环流减弱控制的东亚夏季风减弱，导致了中国南北季风降水分布的这种差异。在4.2ka BP事件期间，雨带在南部位置停留的时间更长，导致中国南北之间存在明显的湿度梯度。
Although the collapses of several Neolithic cultures in China are considered to have been associated with abrupt climate change during the 4.2 ka BP event (4.23.9 ka BP), the timing and nature of this event and the spatial distribution of precipitation between northern and southern China are still controversial. The hydroclimate of this event in southeastern China is still poorly known, except for a few published records from the lower reaches of the Yangtze River. In this study, a high-resolution record of monsoon precipitation between 5.3 and 3.57 ka BP based on a stalagmite from Shennong Cave, Jiangxi Province, southeast China, is presented. Coherent variations in delta O-18 and delta C-13 reveal that the climate in this part of China was dominantly wet between 5.3 and 4.5 ka BP and mostly dry between 4.5 and 3.57 ka BP, interrupted by a wet interval (4.2-3.9 ka BP). A comparison with other records from monsoonal China suggests that summer monsoon precipitation decreased in northern China but increased in southern China during the 4.2 ka BP event. We propose that the weakened East Asian summer monsoon controlled by the reduced Atlantic Meridional Overturning Circulation resulted in this contrasting distribution of monsoon precipitation between northern and southern China. During the 4.2 ka BP event the rain belt remained longer at its southern position, giving rise to a pronounced humidity gradient between northern and southern China.