南极罗斯海JOIDES海槽末次冰期以来底栖有孔虫组合及其对冰架扩张与消融的响应  

BENTHIC FORAMINIFERA ASSEMBLAGES AND THEIR RESPONSE TO ICE SHELF CHANGES IN THE JOIDES TROUGH OF THE ROSS SEA, ANTARCTICA SINCE THE LAST GLACIAL PERIOD

作　　者：樊加恩 王汝建[1] 丁旋[2] 武力[1] FAN Jiaen;WANG Rujian;DING Xuan;WU Li(State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China;School of Ocean Sciences,China University of Geosciences.Beijing 100083.China)

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092 [2]中国地质大学(北京)海洋学院,北京100083

出　　处：《微体古生物学报》2021年第1期93-111,共19页Acta Micropalaeontologica Sinica

基　　金：国家自然科学基金(编号:42030401,41776191);自然资源部国家海洋局极地考察办项目(RFSOCC2020-2022-No.16&17)共同资助。

摘　　要：罗斯冰架的进退对全球气候和世界大洋变化具有重要影响。本研究分析了在南极罗斯海陆架西北部JOIDES海槽钻取的ANT31-JB06岩芯沉积物中的底栖有孔虫化石组合,结合该钻孔已有研究,重建末次冰期以来罗斯冰架在该地区的扩张与消融历史。Q型因子分析表明,研究区底栖有孔虫可划分为四个组合:Miliammina arenacea组合指示生产力高,可能受高盐陆架水影响的环境;Globocassidulina spp.组合指示强烈冰川影响、低生产力的冷水环境;Trifarina earlandi组合指示强水动力环境;Lagena spp.组合的变化表明沉积环境快速变化,但其具体环境意义有待进一步研究。末次冰期(36.6-17.2 ka)时罗斯冰架呈波动增长并逐渐向外陆架扩张,21.8-17.2 ka时增长至最大位置,冰架接地线到达JOIDES海槽ANT31-JB06岩芯位置附近。罗斯冰架在17.2 ka左右逐渐开始融化。17.2-14 ka罗斯冰架发生大面积融化,随后冰架消融减缓(14-11.7 ka)。全新世早期(11.7-9.7 ka)罗斯冰架在JOIDES海槽崩塌并逐渐后退离开,9.7-1 ka该岩芯位置处附近逐渐转变为开阔海洋环境,1 ka以来该处沉积环境出现快速变化。Changes in the Ross Ice Shelf(RIS) have a strong impact on the global climate and the world ocean. In this study, Core ANT31-JB06 that drilled from JOIDES trough on the northwest Ross Sea continental shelf, Antarctica was investigated to reconstruct the process of RIS expansion and retreat since the last glacial period by analyzing the foraminifers. Four benthic foraminiferal assemblages(FAs) were established based on the Q-mode analysis. Mi-liammina arenacea FA represents an environment with high productivity and may be affected by high-salinity shelf water. Globocassidulina spp. FA indicates a cold water environment with strong glacier influence and low productivity. Trifarina earlandi FA represents a strong hydrodynamic environment. The change of the Lagena spp. FA indicates a rapid change in the sedimentary environment, but its specific environmental significance needs further study. During the last glacial period(~36.6-17.2 ka), the RIS gradually expanded to the outer shelf, reaching the maximum extent at~21.8-17.2 ka when the grounding line was near the core location. The RIS began to retreat after~17.2 ka. A significant melting of RIS was at~17.2-14 ka, followed by a slow-down or cease of retreat at 14-11.7 ka. The RIS collapsed in the JOIDES Trough and gradually retreated away during the Early Holocene(~11.7-9.7 ka). The studied region gradually became open sea during~9.7-1 ka, and the sedimentary environment had rapid fluctuations over the last 1 kyr.

关 键 词：底栖有孔虫组合 因子分析 古环境演变 末次冰期 罗斯海 

分 类 号：P736.22[天文地球—海洋地质] Q915[天文地球—海洋科学]