A 3.3-m-thick, 74.5-m-long ancient wood layer was discovered in Zhoushan Archipelago, East China Sea. The ancient woods were well preserved except for weak silicification of wood bark, and abundant amount of leaves, fruits and seeds were found therein. The distribution characteristics of the ancient woods and well-preserved ancient wood stumps indicated the native origin of these ancient woods. The ancient plants as well as their leaves, fruits and seeds were all preserved well, pointing to a possible sudden deposition event. As inferred from the radiocarbon dating results, the abrupt deposition of ancient wood layer was during the period 5900–5600 yr BP, when the palaeoclimatic records reveal intensified summer monsoon winds, strong winter monsoon winds, and very low ENSO activity. We suggest that the formation of the ancient wood layer was very likely caused by the coaction of a strong storm surge and rapid sea level rise, which became more frequent and intensive during this period. The findings of this study imply the potential risk of strong storm surges in the coastal area of the East China Sea, which should be considered in future planning and construction of buildings.

在东海舟山群岛发现了一个厚3.3米，长74.5米的古木层。除了木皮的硅化作用较弱之外，古木保存完好，并且在那里发现了大量的叶子，果实和种子。古木和保存完好的古木树桩的分布特征表明了这些古木的起源。古老的植物以及它们的叶子，果实和种子都保存完好，表明可能发生突然的沉积事件。从放射性碳测年结果可以推断，古木层的突然沉积是在BP 5900-5600年期间，当时的古气候记录显示夏季风增强，冬季风增强和ENSO活性很低。我们认为，古木材层的形成很可能是由于强烈的风暴潮和海平面迅速上升的共同作用造成的，在此期间这变得更加频繁和密集。这项研究的结果表明，在东海沿岸地区强烈风暴潮的潜在风险，应在将来的建筑物规划和建设中予以考虑。