Late Quaternary sedimentary environmental evolution offshore of the Hangzhou Bay,East China——implications for sea level change and formation of Changjiang alongshore current

这研究集中于 Hangzhou 海湾近海的沉积环境变化，华东，自从晚第四级。AMS < 啜 class= “ a-plus-plus ” > 14 从核心 CJK10，岩性学，有孔虫类的分发，重矿物质，和 S 和 Cl 元素的 C 年龄在 23.211.0 cal ka BP 期间显示出河的平台环境；一对潮汐公寓的环境沿岸在 11.010.2 cal ka BP 期间；并且有相对低的沉积的浅海洋的环境自从 4.3 cal ka BP，评估 0.10.22 cm/a。高 depositional 从 10.9 ～ 10.2 cal ka BP 评估 1.6 cm/a 源于快速的海水平上升从 44 创造的足够的住所空间 m 到 33 m 从本地河边的高沉积交货，并且由潮汐公寓的植被的沉积的有效套住。海水平上升的率是可变的；自从 10.6 cal ka BP 1.2 cm/a 相对从 10.9 ～ 10.6 cal ka BP 2.1 cm/a 高、更低。Changjiang 沿著岸水流穿过 Hangzhou 海湾比 9.4 cal ka BP 晚在华东海的内部架上形成泥楔。CJK10 地点从近似 9.4-9.2 cal ka BP 是潮主导的架环境和富有经验的侵蚀到 4.3 cal ka BP。depositional 中断被 Changjiang 沿著岸水流引起，它在 9.4-7.5 cal ka BP 期间是相对弱的并且在 7.5-4 cal ka BP 期间在力量增加了。从 4.3 cal ka BP，来自 Changjiang 河的大量沉积部分在 Hangzhou 海湾的大陆人架上被扔，一些搬运了向南方。因此，这研究澄清导出 Changjiang 的沉积疏开和免职的历史，尽管在自从 4.3 cal ka BP 当前的 Changjiang 沿著岸的变化的一个详细记录是困难的因为证据的缺乏，获得。

This study focuses on sedimentary environmental changes offshore of Hangzhou Bay, East China, since the Late Quaternary. AMS ^14C ages from core CJK10, lithologies, distribution of foraminifera, heavy minerals, and S and C1 elements show a fluvial terrace environment during -23.2-11.0 cal ka BP; a littoral to tidal-flat environment during 11.0-10.2 cal ka BP; and a shallow marine environment with a relatively low sedimentation rate （0.1-0.22 cm/a） since 4.3 cal ka BP. High depositional rates （-1.6 cm/a） from 10.9 to 10.2 cal ka BP resulted from sufficient accommodation space created by rapid sea level rise from -44 m to -33 m, from high sediment delivery by local rivers, and effective trapping of sediments by tidal-flat vegetation. The rate of sea level rise was variable; relatively high from 10.9 to 10.6 cal ka BP （2.1 cm/a）, and lower since 10.6 cal ka BP （1.2 cm/a）. The Changjiang alongshore current crossed the Hangzhou Bay to form the mud wedge on the inner shelf of the East China Sea later than 9.4 cal ka BP. The CJK10 site was a tide-dominated shelf environment and experienced erosion from approximately 9.4-9.2 cal ka BP to 4.3 cal ka BP. The depositional hiatus was caused by the Changjiang alongshore current, which was relatively weak during 9.4-7.5 cal ka BP and increased in strength during -7.5-4 cal ka BP. From -4.3 cal ka BP, a large amount of sediment from the Changjiang River was partly deposited on the continental shelf of Hangzhou Bay with some transported southward. Therefore, this study clarifies the history of Changjiang-derived sediment dispersal and deposition, although a detailed record of the changes in the Chang3iang alongshore current since 4.3 cal ka BP is difficult to obtain because of the scarcity of evidence.