15 ka以来罗斯海陆架岩心沉积学记录及古海洋学意义

本文对取自罗斯海陆架的JB04岩心沉积物进行AMS14C测年、粒度、有机碳等测试，结合沉积物粒度组分因子分析，研究该岩心的沉积学记录，探讨其古海洋学意义。结果显示:JB04岩心沉积物的底部年龄为15 ka；沉积物粒度组分因子分析提取出3个环境敏感粒级，分别代表正常冰海沉积、低能海洋沉积和高能海洋沉积；综合沉积物岩相及沉积物组成特征，可以将岩心分为4段，从底部到顶部依次为主要受冰盖刮蚀影响的冰盖下沉积、属低能海洋环境的冰架下沉积、属高能海洋环境的冰架前缘沉积和主要受冰山影响的季节性海冰区沉积。该岩心的沉积地质记录及其古海洋学研究对全面认识罗斯海的海洋环境演变具有重要的意义。

Sedimentary record and paleoceanographic implications of the core on the continental shelf off the Ross Sea since 15 ka

In this study, based on the multi-parameters measurements, including AMS¹⁴C dating, organic carbon, grain size and factor analysis of grain size data, of gravity core JB04, collected in the continental shelf of the Ross Sea during the 31^st China Antarctic scientific expedition, the sedimentary strata and processes were studied and the paleocenography significance was discussed. The results shown that the age of the core sediment is 15 ka, and the core sediment can be divided into 3 types, namely as the normal ice-sea deposition, low marine hydrodynamic deposition and high marine hydrodynamic deposition, respectively. According to the distributions of sediment deposition strata, the core can be divided into 4 layers. From the bottom to the top, the first deposited layer was formed in the marine environment while the ocean was covered by ice sheet, and so the sedimentation process was mainly dominated by glacial scraping corrosion. The second deposition layer was formed under the ice shelf in low marine hydrodynamic environment and the third deposition layer was formed in front of the ice shelf in high marine hydrodynamic environment. The top deposition layer was formed in seasonal sea ice environment and was affected by iceberg. The study of marine sedimentary processes of the Ross Sea is very siginificant to complately understanding the evolution of marine environment in the Antarctica.