A 3-kyr plateau of middle Holocene higher sea levels on the central Kanto Plain, Japan
A 3-kyr plateau of middle Holocene higher sea levels on the central Kanto Plain, Japan
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DOI：
10.1016/j.quascirev.2022.107769
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发表时间：
2022-11
影响因子：
4
通讯作者：
S. Tanabe
中科院分区：
文献类型：
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作者：
S. Tanabe
亚洲、澳大利亚和南美洲全新世中期7- 4ka的高海平面在持续时间和稳定性上各不相同。东京市区位于关东平原中部的冲积低地和沿海低地，已进行了大量的考古发掘。在这项研究中，74个海平面指数点和241个限制数据点是从日本的科学论文和挖掘报告中汇编的109个地点的关东平原中部。这些数据表明，相对平均海平面从8 ka时的−4 ± 1.5 m变化到7- 4ka期间的3 ± 1.5 m，再到3 ka时的−1.5 ± 1 m，然后到2-0 ka期间的0 ± 1 m。在关东平原中部的7- 4ka海平面高原期间，海平面没有波动。关东平原中部52个测点的高度分布表明，在90 km × 90 km的区域内，海平面稳定了3 kyr，没有局部差异。在3 ka的临时海平面下降对应的“弥生回归”，这是以前报道的关东平原中部，虽然其驱动机制是未知的。地壳形变可以忽略不计，因为它不如春季潮差重要，这是大约。关东平原中部7 ka时的3 m。通过使用密集的数据集，以确认中全新世高海平面高原的关东平原中部的发生，这项研究强烈表明，冰川融化发生两个步骤，在7 ka和4 ka。
Middle Holocene higher sea levels during 7–4 ka in Asia, Australia, and South America varied in duration and stability. Abundant archaeological excavations have been carried out in the Tokyo urban area, which is situated on the alluvial and coastal lowlands of the central Kanto Plain. In this study, 74 sea-level index points and 241 limiting data points were compiled from Japanese scientific papers and excavation reports for 109 locations on the central Kanto Plain. These data suggest that the relative mean sea level changed from −4 ± 1.5 m at 8 ka to 3 ± 1.5 m during 7–4 ka, to −1.5 ± 1 m at 3 ka, and then to 0 ± 1 m during 2–0 ka. During the 7–4-ka sea-level plateau on the central Kanto Plain, the sea level did not fluctuate. The height distribution at 52 locations on the central Kanto Plain shows that sea level remained stable for 3 kyr, with no local differences in the duration, in an area of 90 km × 90 km. The temporary sea-level drop at 3 ka corresponds to the “Yayoi regression”, which has been previously reported on the central Kanto Plain, although its driving mechanism is unknown. Crustal deformation can be neglected as less important than the spring tidal range, which was ca. 3 m at 7 ka on the central Kanto Plain. By using a dense dataset to confirm the occurrence of a middle Holocene higher sea-level plateau on the central Kanto Plain, this study strongly suggests that glacier melting occurred two steps, at 7 ka and 4 ka.