摘要
本文研究采自位于南极罗斯海西部的ANT32-RB16C柱状沉积物,根据粒度、有机碳和生物标志化合物数据探讨末次冰盛期(24.8~20 ka BP)以来该地区有机质来源及沉积环境特征。该柱状样记录了冰架下沉积、冰架前沉积、开阔海域沉积的沉积环境。指示有机质来源的生物标志化合物指标表明该柱状样中所含有机质主要为浮游植物、细菌等海源输入,同时伴有少量陆源物质混合输入。末次冰盛期,由于冰架的影响有机质含量较低,环流影响使得有机质受低等浮游藻类生物等海源影响较大。末次冰消期(20~11.7 ka BP),罗斯冰架消退,冰川溶解释放的有机质在此沉积,使得陆源有机质输入增多,有机质含量升高。进入全新世,有机质含量较末次冰盛期和末次冰消期明显升高,海源输入比例增大,同时细菌等原核生物增多,导致短链正构烷烃降解程度较大。研究区的氧化还原环境主要受冰架与海冰限制作用的影响,与有机质含量和高氧的南极底层水关系不大。总体来说,从末次冰盛期到末次冰消期,研究区沉积环境受罗斯冰架进退影响,全新世以来受气候变化影响。
Analyses of grain size,organic carbon and biomarker have been carried out for the core ANT32-RB16 C,in order to identify the source of organic matter and reconstruct the sedimentary environment since the Last Glacial Maximum in the western Ross Sea.From the bottom to the top within the core,sub-ice-shelf,pre-ice-shelf and open-marine sedimentary environments can be differentiated.The combined parameters of biomarker indicate that organic matter is mainly a mixed input of terrigenous and marine origin.During the Last Glacial Maximum(24.8–20 ka BP),under the influence of ice sheet and the current condition,the organic matter content was low and its source was associated mainly with a marine origin,with a relatively low plankton productivity.During the Last Deglaciation(20–11.7 ka BP),the organic matter released by the dissolution of the glaciers in the retreat process of the Ross Ice Shelf,caused the increase of terrestrial organic matter.During the Holocene,the content of organic matter increased significantly,together with the proportion of marine origin input.The number of prokaryotes such as bacteria increased,resulting in a greater degree of degradation of short-chain n-alkanes.The redox condition in the study area is mainly affected by the ice shelf and sea ice limitation,and has little relationship with the organic matter content and the high-oxygen Antarctic Bottom Water.In general,from the Last Glacial Maximum to the Last Deglaciation,the study area sedimentary environment was affected by the Ross Ice Shelf,and by the climate since the Holocene.
作者
宋乐慧
韩喜彬
李家彪
高抒
刘庚
龙盼盼
Song Lehui;Han Xibin;Li Jiabiao;Gao Shu;Liu Geng;Long Panpan(Ministry of Education Key Laboratory for Coast and Island Development,Nanjing University,Nanjing 210023,China;Key Laboratory of Submarine Geosciences,State Oceanic Administration,Hangzhou 310012,China;Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China)
出处
《海洋学报》
CAS
CSCD
北大核心
2019年第9期52-64,共13页
基金
“全球变化与海气相互作用”专项(GASI-GEOGE-03,GASI-04-01-02)
国家自然科学基金(41476047,41476069)
极地考察业务化与科研：国家南极观测监测网运维与管理
极地考察业务化与科研：南北极环境综合考察评估与管理
