晚第四纪东南极普里兹湾外沉积物磁化率特征及其古环境意义  

Magnetic Susceptibility of Late Quaternary Sediments off Prydz Bay,East Antarctica:Characteristics and Paleo-environmental

作　　者：武力 李隆威 王汝建[2] 肖文申[2] 陈志华 葛淑兰 黄鑫[1] WU Li;LI Long-wei;WANG Ru-jian;XIAO Wen-shen;CHEN Zhi-hua;GE Shu-an;HUANG Xin(College of Ocean and Meteorology,Guangdong Ocean University,Zhangjiang 524088,China;State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China;Key Laboratory of Marine Geology and Metallogeny,First Institute of Oceanography,Ministry of Natural Resources,Qingdao 266061,China)

机构地区：[1]广东海洋大学海洋与气象学院,广东湛江524088 [2]同济大学海洋地质国家重点实验室,上海200092 [3]自然资源部第一海洋研究所海洋地质与成矿重点实验室,山东青岛266061

出　　处：《广东海洋大学学报》2023年第3期107-116,共10页Journal of Guangdong Ocean University

基　　金：国家自然科学基金面上项目(42276077);同济大学海洋地质国家重点实验室开放基金(MGK202207);国家自然科学基金重点项目(42030401)。

摘　　要：【目的】研究东南极普里兹湾外深海区晚第四纪沉积物序列磁化率特征,提取磁化率所蕴含的古环境信息。【方法】使用岩芯多参数扫描仪测试研究区四个沉积物岩芯的磁化率,计算磁化率合成曲线,校正磁化率稀释效应和粒度效应。【结果】四个岩芯的磁化率具有相似而不相同的旋回性变化特征。磁化率合成曲线在约130、225、250、340、410和470ka等处存在低值,这些低值区对应着冰期向间冰期过渡的时期(包含冰消期)。【结论】来自普里兹湾陆架的陆源碎屑磁铁矿是岩芯磁化率的主要携带者,它们随洋流/浊流搬运至深海沉积。沉积物磁化率信号受到低磁化率组分的稀释和粒度效应的显著影响。扣除稀释效应和粒度效应后,合成磁化率信号表现出明显的冰期-间冰期旋回性变化特征。这种变化模式与普里兹湾陆架老沉积物的移动和再沉积过程有关,反映兰伯特冰川体系在冰期-间冰期时间尺度上的消长。东南极冰川体系在晚第四纪呈动态变化,对全球海平面变化具有潜在贡献。【Objective】To investigate the magnetic susceptibility characteristics of late Quaternary sediments in the deep sea area off Prydz Bay,East Antarctica and to extract the information on paleo-environmental evolution.【Method】The magnetic susceptibility of four sediment cores collected from the study area was tested with the core multi-parameter logger,and a magnetic susceptibility synthesis curve was made.The dilution effect and grain-size effect were corrected for the curve.【Result】Magnetic susceptibility records of the four cores show similar but different cyclic fluctuations.Intervals of low values occur at about 130,225,250,340,410 and 470 ka,corresponding to transitions from glacial to interglacial(including deglaciation)periods.【Conclusion】Detrital magnetite from the Prize Bay shelf is the main carrier of magnetic susceptibility,transported to the deep sea mainly by ocean current/turbidity current;The sediment magnetic susceptibility signal is significantly affected by the dilution and grain-size effects of the components with low magnetic susceptibility.After the dilution effect and particle size effect being deducted,the synthetic magnetic susceptibility signals show obvious glacial interglacial cycle.This change pattern is related to the movement and re-deposition of the old sediments in the Prydz Bay shelf,reflecting the growth and decline of the Lambert Glacier on the glacial interglacial time scale.It is confirmed that the glacier system of the East Antarctica is dynamic in late Quaternary.

关 键 词：东南极 普里兹湾 磁化率 晚第四纪 冰川 

分 类 号：P539.3[天文地球—古生物学与地层学]