Geochemical and micropaleontological impacts caused by the 2011 Tohoku-oki tsunami in Matsushima Bay, northeastern Japan
Geochemical and micropaleontological impacts caused by the 2011 Tohoku-oki tsunami in Matsushima Bay, northeastern Japan
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2011 年东北冲海啸对日本东北部松岛湾造成的地球化学和微型古生物学影响
DOI：
10.1016/j.margeo.2018.10.007
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发表时间：
2019
期刊：
影响因子：
2.9
通讯作者：
O.
中科院分区：
文献类型：
--
作者：
Irizuki;T.;Fujiwara;O.;Yoshioka;K.;Suzuki;A.;Tanaka;Y.;Nagao;M.;Kawagata;S.;Kawano;S.;Nishimura;O.
我们目前的地层，地球化学（CNS元素分析），和微体古生物（介形虫组合）的证据，2011年东北冲海啸的影响，在日本东北部的松岛湾，并检查恢复过程后的影响，海湾环境使用短沉积物岩心从两个不同的地形设置在水深约4米。在这两个地点，海啸沉积物由两个沉积层组成，记录了第一次海啸的上升和下降。在连接海湾与太平洋的通道附近的西部站点，第一次海啸波侵蚀了海湾底部沉积物，留下了由富含贝壳碎片的中砂组成的海啸沉积物，但具有稀疏数量的小型底栖介形类。相比之下，在东部的网站，这是由许多小岛包围，第一波侵蚀很少的海湾底部沉积物和留下海啸沉积物组成的桑迪泥，丰富的外来介形类，如植物物种，浅海砂栖息物种，和微咸水物种。海啸后的沉积物主要由富含有机物的泥浆组成，其中的有机物主要来自海洋浮游生物。海啸沉积物中的介形虫组合缺乏生活在水深>50 m的近海物种，并以松岛湾及其邻近的近岸、上亚沿岸区和半咸水环境中的物种为主。从深水近海区到核心站点的距离太远，海啸波无法运输介形虫阀。
We present stratigraphic, geochemical (CNS elemental analysis), and micropaleontological (ostracode assemblages) evidence for the 2011 Tohoku-oki tsunami impact in Matsushima Bay, northeastern Japan, and examine the recovery process after the impact to the bay environment using short sediment cores from two different topographic settings at a water depth of approximately 4 m. At both sites, tsunami deposits are composed of two sedimentary layers that recorded the first tsunami run-up and backwash. At the western site near the channel that connects the bay with the Pacific Ocean, the first tsunami wave eroded the bay floor sediments and left the tsunami deposits composed of medium sand rich in shell fragments, but with sparse numbers of meiobenthic ostracodes. By contrast, at the eastern site, which is surrounded by many small islands, the first wave eroded very little of the bay floor sediments and left tsunami deposits consisting of sandy mud, rich in exotic ostracodes, such as phytal species, shallow marine sand dwelling species, and brackish water species. Overlying post-tsunami deposits are composed mainly of organic-rich mud in which organic matter was derived primarily from marine plankton. Ostracode assemblages in the tsunami deposits lack the offshore species that live in water depths >50 m and are dominated by the species from Matsushima Bay and its adjacent nearshore, upper sublittoral areas, and brackish water environments. The distance from deep-water offshore areas to the core sites is too far to transport ostracode valves by tsunami waves.