晚更新世以来鲍威尔海盆D3-5柱样化石硅藻组合特征及其环境指示意义  

CHARACTERISTICS AND ENVIRONMENTAL IMPLICATIONS OF DIATOMS FROM THE D3-5 CORED SAMPLE IN THE POWELL BASIN SINCE THE LATE PLEISTOCENE

作　　者：陈敏[1,2,3] 林燕婷 王凤 李云海 刘璇 李家玉[2,4] 黄清 CHEN Min;LIN Yan-Ting;WANG Feng;LI Yun-Hai;LIU Xuan;LI Jia-Yu;HUANG Qing(College of Marine Living Resource Sciences and Management,Shanghai Ocean University,Shanghai 201306,China;Third Institute of Oceanography,Ministry of Natural Resources,Xiamen 361005,China;Fujian Provincial Key Laboratory of Marine Physical and Geological Processes,Xiamen 361005,China;College of Ocean and Earth Sciences,Xiamen University,Xiamen 361005,China;School of Advanced Manufacturing,Fuzhou University,Jinjiang 362251,China)

机构地区：[1]上海海洋大学海洋生物资源与管理学院,上海201306 [2]自然资源部第三海洋研究所,福建厦门361005 [3]福建省海洋物理与地质过程重点实验室,福建厦门361005 [4]厦门大学海洋与地球学院,福建厦门361005 [5]福州大学先进制造学院,福建晋江362251

出　　处：《海洋与湖沼》2025年第2期337-351,共15页Oceanologia Et Limnologia Sinica

基　　金：福建省自然科学基金计划项目,2023J011378号;南极重点海域对气候变化的响应和影响项目,IRASCC2020-2023-01-03-02号,IRASCC2020-2023-01-02-03号。

摘　　要：为重建晚更新世以来鲍威尔海盆的古海洋环境演变历史,本文对南极半岛鲍威尔海盆D3-5柱样的硅藻进行了分析,D3-5柱样的156个样品中共鉴定出硅藻54个种和变种,以海水种和冷水种为主。通过硅藻分析,将晚更新世以来鲍威尔海盆的海洋环境变化划分如下:58.6~72.5 ka BP期间,硅藻以冷水种和海冰种为主,并出现沿岸种,推测因南极冰盖增长,鲍威尔海盆受极地冷水团控制,气候出现明显冷-暖交替,而且海平面较低,站位水深较浅;40.7~58.6 ka BP期间,出现明显气候冷-暖转变,海洋环境受气候变化影响较大,变得不稳定,由于海冰融化、温盐循环加强和冰筏碎屑事件的频发导致硅藻种类、丰度骤减;26.2~40.7 ka BP期间,硅藻种类明显增加,出现海冰种,冷水种增加,推测处于末次冰盛期的冰盖增长前期,中纬度暖水团在南极海区的影响范围向南扩大,冷、暖水团强烈混合,驱动温盐循环;26.2 ka BP至今,硅藻丰度增加,极地冷、暖水团混合的指示种Fragilariopsis oceanica指示研究区的表层与底层水体混合增强,海冰覆盖面积持续增大,威德尔环流势力增强,中纬度暖水势力减弱。总体来说,自晚更新世以来鲍威尔海盆经历了冷期(南极冰盖发育)-暖期-冷期(末次冰盛期)的阶段转变,而在深海氧同位素3阶段(marine isotope stages 3,MIS 3)中存在一段较长时间的冰筏碎屑事件时期。A total of 156 sedimentary diatom specimens from D3-5 gravity cored sample(316 cm long)in the Powell Basin(62.2322°S,50.3449°W;water depth 3397 m)in Antarctic during the China’s 28th Antarctic Scientific Expedition from 2011 to 2012 were analyzed,from which 54 species and variants of diatoms were identified and they were dominated by marine and cold-water species.The following stages of the changes of the Powell Basin marine environment since the Late Pleistocene were established based on diatom analysis.During the 58.6~72.5 ka BP period,diatoms were dominated by cold-water and sea-ice species,and coastal species appeared.It was inferred that due to the growth of the Antarctic ice sheet,the Powell Basin was under the control of polar cold-water mass,with distinct cold-warm alternations in climate.Besides,the sea level was low and the water depth was shallow.During the 40.7~58.6 ka BP period,there was an obvious climate cold-warm change.The marine environment was greatly affected by climate change and becomes unstable.It was inferred that due to the melting of sea ice,the strengthening of thermohaline circulation,and the frequent occurrence of ice-rafted debris events,the species and abundance of diatoms decreased sharply.In the 26.2~40.7 ka BP period,the diatom species increased significantly,and the sea-ice appeared and cold-water species increased.It was speculated that in the early stage of ice-sheet growth of the Last Glacial Period,the influence range of the mid-latitude warm water mass in the Antarctic Sea area expanded southwards,and the cold and warm water masses were strongly mixed to drive the thermohaline circulation.From 26.2 ka BP to the present,the abundance of diatoms increased with the occurrence of diatom species Fragilariopsis oceanica indicating mixed with polar cold and warm water,suggesting that the mix of surface and bottom water in the study area was enhanced.Besides,the sea ice coverage area continued to expand,the Weddell Circulation was strengthened,while the influence of mid-latitud

关 键 词：硅藻 鲍威尔海盆 沉积柱样 海洋环境 

分 类 号：P736.22[天文地球—海洋地质]