黄海南部海门近岸牡蛎礁发育的物质基础与环境背景

中国的现代牡蛎礁多发育在河口,但位于黄海南部的海门市近岸牡蛎礁却发育在非河口地区。利用对岩芯和剖面进行的岩相、粒度、硅藻及¹⁴C年代等因子的分析测试数据,对黄海南部的海门市近岸牡蛎礁的发育场所和环境背景进行了探讨。结果发现,该地在距今5630年左右发生了一次重要的沉积环境变化,由之前的潮间带环境转变为之后的河口砂坝或者受河口影响的潮流砂脊相环境,形成了适宜牡蛎生长和牡蛎礁发育的条件。尽管牡蛎礁现在出露在粉沙淤泥质潮滩上,但是其发育的基底不是粉砂淤泥质潮滩,而是河口砂坝或者受河口影响的潮流砂脊。黏土矿物特征还显示出,海门牡蛎礁的发育还与长江口的影响密切相关。

Environmental background of oyster reef development in near-shore Haimen of southern Yellow Sea

Most living oyster reefs in China develop in the estuaries such as Xiaoqing estuary, Zimaigou estuary etc. However, Liyashan oyster reef, which lies at the southern Yellow Sea coast near Haimen, Jiangsu province, develops in the non-estuary. Despite some researchers have studied its modern landform and environment, as well as because of the sand layer on the surface, we still do not know on what basement the oyster reef developed is. In addition, the sea water here has a high salinity which is beyond the best range of the oyster growing. Then a question arises: how was the environment during the oyster reef development? In order to answer these questions, we have been to this region several times to do investigation and sampling. The results indicate that the basement of the oyster reef is sandy sediments of estuary bar or tidal current ridge impacted by estuaries, rather than tidal flat deposits.