白令海Navarinsky海底峡谷地震剖面解译

Interpretation to the seismic profile of Navarinsky Canyon,Bering Sea

第五次北极科学考察在北极区的白令海首次进行了高分辨率单道地震作业。Navarinsky峡谷头部测线BL11-12剖面中部识别出不对称沙波,陡的一面朝向陆架,波高约为9m、波长约为882m。结合站位U1345的沉积速率及站位U1344表层纵波速率推测沙波沉积可以追溯到中更新世(距今约0.258Ma),同时近陆架的洼地逐渐填平。将地层分为3个沉积层,分析沉积物变化情况,结合0.25Ma以来白令海海平面变化历史,推测最大海退事件对应的界面。结合沙波的地理位置及海平面变化情况,认为内波对沙波的形成起主要作用。

High resolution single channel seismic operation was carried out in the Bering Sea during the 5th Chinese National Expedition.Asymmetric sand waves were identified on line BL11-12 seismic profile in the head of Navarinsky Canyon.The steep faces of asymmetric sand waves were on-shelf direction,the averaged wave height was 9m and length was 882 m.There was a sedimentary depression at the end of line BL11-12 seismic profile.Combined the sedimentation rate of site U1345 and Vp of superficial sediment at site U1344,Infered that sand waves began deposit and sedimentary depression was filled since the Middle Pleistocene（about 0.258Ma）.Stratum was divided into three sediments.Analyzing changes of grain size on the profile,we can speculate the surface relating to the maximum regression combined with the change of the bering sea level.Taking every aspect into consideration,draw conclusion that sand waves formed during the low sea level in Middle Pleistocene,and internal wave played a significant role.