Early to mid‐Holocene rapid sea‐level rise and coastal response on the southern Yangtze delta plain, China
Early to mid‐Holocene rapid sea‐level rise and coastal response on the southern Yangtze delta plain, China
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DOI：
10.1002/jqs.2662
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发表时间：
2013-10
影响因子：
2.3
通讯作者：
Zhanghua Wang;Qing Zhan;Haiyan Long;Y. Saito;Xiaoqin Gao;Xuxu Wu;Lin Li;Yanan Zhao
中科院分区：
文献类型：
--
作者：
Zhanghua Wang;Qing Zhan;Haiyan Long;Y. Saito;Xiaoqin Gao;Xuxu Wu;Lin Li;Yanan Zhao
我们利用加速器质谱（AMS）对长江三角洲南部平原11个岩芯中全新世潮上带底部到潮间带上部相的沉积物进行了¹⁴C测年，以重建8.5 - 8.0 cal ka BP（距今千年，calendar years before present）的相对海平面。对其中三个岩芯进一步进行了AMS ¹⁴C测年，并用于研究全新世早期到中期海平面快速上升过程中沉积地貌环境的演变。结果表明，从8.5到8.3 cal ka BP，相对海平面以每年约30毫米的速度上升，从8.3到8.0 cal ka BP，相对海平面以每年约10毫米的速度上升。在8.5 - 8.3 cal ka BP，由于海平面快速上升，发生了从潮上带到低潮间带环境的退积，在8.3 - 7.9 cal ka BP，发生了从中潮间带到高潮间带的加积。在7.9 - 7.2 cal ka BP，潮间带进一步后退，这意味着此时平均海平面上升速率超过每年5毫米。我们认为，在8.3 - 8.5 cal ka BP期间相对海平面的快速上升以及随后较慢的上升导致了沿海地区的剧烈变化，这些变化是理解沿海地区对未来海平面上升响应的关键现象。
We used accelerator mass spectrometry (AMS) 14C‐dated sediments of the Holocene basal supratidal flat to upper tidal flat facies in 11 cores on the southern Yangtze delta plain to reconstruct relative sea levels of 8.5–8.0 cal ka BP. Three cores were further AMS 14C dated and used to examine the evolution of sedimentary geomorphological environments in response to the rapid sea‐level rise during the early to mid‐Holocene. Results demonstrate relative sea‐level rise of around 30 mm a−1 from 8.5 to 8.3 cal ka BP and around 10 mm a−1 from 8.3 to 8.0 cal ka BP. Retrogradation from supratidal to lower tidal flat environments occurred in response to the rapid sea‐level rise at 8.5–8.3 cal ka BP, and aggradation from middle to upper tidal flat occurred at 8.3–7.9 cal ka BP. Further retreat of the tidal flat at 7.9–7.2 cal ka BP implies a mean sea‐level rise rate exceeding 5 mm a−1 at this time. We suggest that the rapid relative sea‐level rise during 8.3–8.5 cal ka BP and subsequent slower rise caused drastic changes in the coastal zone and that these changes are key phenomena for understanding the coastal response to future sea‐level rise.