楚科奇海北部浅地层结构对古冰川活动的指示

Characteristics of the Shallow Strata Structure on the Northern Margin of the Chukchi Sea and its Significance on Palaeo-Glaciation

北极周边陆架海域第四纪时期曾多次受到冰川活动的影响,但楚科奇海作为北极陆架海之一,其第四纪古冰川活动的存在尚需要更多数据的支持。本文利用2019年中国第十次北极科学考察中获取的楚科奇海北部的陆架和陆坡上700余km的高分辨率浅地层剖面数据,在剖面上识别出了冰川接地带楔状体、冰成碎屑流沉积、冰下混杂沉积和冰下水流沉积等多种类型的冰成沉积结构,可知研究区曾受到古冰川作用的影响。陆架坡折处被半远洋沉积隔开的上下两套接地带楔状体、隆起东南宽海槽中冰成混杂沉积中的层状泥质透镜体都指示研究区存在不止一期古冰川活动,且均曾扩展到楚科奇陆架边缘。

Many marginal seas in the Arctic have been influenced by Quaternary glaciation.However,due to the data insufficiency,the evidences for the influences of Quaternary glaciation on the Chukchi Sea are still lacking.More than 700 km high-resolution shallow sub-bottom profiles were acquired on the Northern Margin of the Chukchi Sea,during China’s 10th Arctic Scientific Expedition Cruise in 2019.Various type of glacial features,including the grounding-zone wedges,the glacial debris-flow deposits,the sub-glacial diamictons,and sub-glacial water flow deposits,are revealed on the shallow sub-bottom profiles.All these features indicate that more times glacial activities affected the northern Chukchi Sea,even up to the shelf margin.