Late Quaternary environmental change in Oujiang delta along the northeastern Zhe-Min Uplift zone (Southeast China)
Late Quaternary environmental change in Oujiang delta along the northeastern Zhe-Min Uplift zone (Southeast China)
复制标题
浙闽隆起带东北部瓯江三角洲晚第四纪环境变化
DOI：
10.1016/j.palaeo.2017.12.012
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Qiang Wang
中科院分区：
文献类型：
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作者：
Shuai Shang;Daidu Fan;Ping Yin;George Burr;Mengying Zhang;Qiang Wang
通过对瓯江三角洲41.9米长的沉积物岩芯的研究，揭示了晚第四纪海岸带的演化历史。采用多种分析方法，包括沉积相分析，放射性碳测年，粒度，元素，微体化石和花粉成分的调查。两个海进-海退序列，分离的古土壤层，确定。多条证据表明，下层序沉积于MIS 3期中早期，气候相对温暖湿润。MIS 3海平面升高（高于-24米）。上部层序是在距今约9.5 cal的海侵过程中古土壤被淹没后形成的。研究结果表明，东亚夏季风存在7次弱事件，其中心年分别为8.4，7.7，6.3，5.7，4.7，2.8和1.8 cal kyr BP。这与东阁洞δ 18 O记录和ECS沉积物柱样的结果相一致，表明东亚夏季风降水是该地区沉积速率的主要控制因素。瓯江三角洲还受到台风和东亚冬季风（EAWM）引起的沿岸流的影响。活跃的台风和相对增强的EAWM发生在弱EASM期间4.9和6.4卡尔Kyr BP之间，在全新世中期产生高沉积速率。我们强调亚洲小河流三角洲作为东亚夏季风、东亚冬季风和台风档案的高度敏感性。这种环境值得进一步作为一种手段，以了解过去的变化以及未来对预测的气候和海平面变化的反应。
We present a history of late Quaternary coastal evolution based on the study of a 41.9-m-long sediment core from the Oujiang Delta. Multiple analytical methods are employed, including sedimentary facies analysis, radiocarbon dating, and the investigations of grain size, elemental, microfossil and pollen compositions. Two transgression-regression sequences, separated by a paleosol layer, are identified. Several lines of evidence indicate that the lower sequence was deposited during the mid-early MIS 3 stage, under a relatively warm and wet climate. An elevated MIS 3 highstand sea level (higher than − 24 m) is observed. The upper sequence was created after the paleosol was flooded during a marine transgression at ~ 9.5 cal kyr BP. Seven weak East Asian Summer Monsoon (EASM) events are identified with central years of ~ 8.4, 7.7, 6.3, 5.7, 4.7, 2.8 and 1.8 cal kyr BP. These coincide with those from the ECS sediment cores and the Dongge Cave δ18O record, indicating that EASM precipitation is a major controlling factor of sedimentation rates in the region. The Oujiang Delta is also subject to typhoon impacts and East Asian winter monsoon (EAWM)-induced coastal currents. Active typhoons and a relatively enhanced EAWM occurred during the weak EASM period between 4.9 and 6.4 cal kyr BP, producing high sedimentation rates in the middle Holocene. We emphasize the high sensitivity of small Asian river deltas as archives of the EASM, EAWM and typhoons. Such environments merit further as a means to understand past changes as well as future responses to projected climatic and sea-level change.