白令海深海异常沉积特征及成因分析  

CHARACTERISTICS OF ABNORMAL DEEP-SEA SEDIMENTS IN THE BERING SEA AND THEIR POSSIBLE CAUSES

作　　者：黄元辉[1] 石学法[1] 葛淑兰[1] 刘焱光[1] 陈志华[1] 王旭晨[2] 吕华华[1] 

机构地区：[1]国家海洋局第一海洋研究所 海洋沉积与环境地质国家海洋局重点实验室,山东青岛266061 [2]中国海洋大学 海洋化学理论与技术教育部重点实验室,山东青岛266100

出　　处：《极地研究》2014年第1期39-45,共7页Chinese Journal of Polar Research

基　　金：南北极环境综合考察与评估专项(CHINARE2012-01-02,CHINARE2013-01-02,CHINARE2013-03-02,CHINARE2013-04-01);中央级公益性科研院所基本科研业务费专项(GY02-2011G18,GY0213G26);国家自然科学基金项目(41106166,41376072,40710069004,41076136)资助

摘　　要：利用中国历次北极科学考察航次在白令海北部陆坡及海盆等深水区所采集的沉积物样品,对其开展沉积学等研究,系统归纳该海域常见的异常沉积类型及特征,并初步探讨其可能成因。BR02孔出现至少3段浊积层,浊积层主要分布于末次冰消期至中全新世。B5-4孔存在至少2段火山碎屑沉积层,其沉积年代分别约为1.3 ka BP和13.2 ka BP。B5-7站表层沉积物中的硅藻组合以新近系硅藻化石Kisseleviella carina Sheshukova-Poretzkaya和Kisseleviella ezoensis Akib为主,且与附近海域其他表层沉积物的硅藻组合面貌差异明显,可能是沉积物再沉积结果,其初始沉积年代大约为早中新世。白令海北部陆缘/陆坡区附近遍布的海底大峡谷对该区沉积物沉积过程具有重要影响,可能是导致该区浊流沉积与再沉积物的主要原因。此外,白令海位于欧亚板块、太平洋板块及北美板块交汇区边缘,其独特的地理位置决定该区地震与火山等构造活动相对活跃,进而进一步促使该区海底异常沉积现象频发。Sediment samples from previous Chinese Arctic Research Expeditions in the northern continental slope and the deep basin of the Bering Sea were used for sedimentological studies. Abnormal sedimentary types and their characteristics are summarized, and their possible causes are preliminarily discussed. At least three turbidite layers appear in core BR02, which are distributed mainly from the last deglacial to the Mid-Holocene. More than two volcaniclastic sedimentary layers were found in Core B5-4, which formed at ca. 1.3 ka BP and 13.2 ka BP. The diatom assemblage of the surface sediment of Core B5-7 is dominated by the Neogene fossil diatoms Kisseleviella carina Sheshukova-Poretzkaya and Kisseleviella ezoensis Akib, which is distinctively different from the assemblages in other adjacent surface sediments. We presume that this could be the result of reworking, and its initial depositional age could be about early Miocene. The numerous submarine canyons incising the continental margin of the Bering Sea may have a large impact on the sedimentary processes, which could be the main reason for the presence of abnormal sedimentation processes in this region. Moreover, the unique location of the Bering Sea, along the margin between the Eurasian Plate and the North American Plate, means that it often suffers from earthquakes and volcanic activity, which in turn promote the frequent occurrence of submarine abnormal sedimentation processes.

关 键 词：白令海 异常沉积 浊流 火山碎屑 再沉积 

分 类 号：P721[天文地球—海洋科学] P736.211