Identification of the thick-layer greigite in sediments of the South Yellow Sea and its geological significances  

作　　者：Jianxing Liu Xuefa Shi Shulan Ge Qingsong Liu Zhengquan Yao Gang Yang 

机构地区：[1]Paleomagnetism and Geochronology Laboratory (SKL-LE),Institute of Geology and Geophysics, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Key Laboratory of Marine Sedimentation and Environmental Geology, First Institute of Oceanography, State Oceanic Administration

出　　处：《Chinese Science Bulletin》2014年第22期2764-2775,共12页

基　　金：supported by the Project of State Oceanic Administration, China (908-01-BC15);the National Natural Science Foundation of China (41374073, 41025013 and40821091)

摘　　要：Magnetic minerals in sediments of the continental shelf are sensitive to environmental changes.Therefore,to determine the exact phases of magnetic minerals is the prerequisite to investigate the paleoenvironmental significances.In this study,a comprehensive rock magnetic investigation,coupled with mineralogical studies,was carried out on the long core NHH01(with a length of 125.64 m)from the central continental shelf of the South Yellow Sea.Single-domain greigite was identified as the dominant magnetic carrier in sediments between44.90 and 51.80 m,and terrigenous magnetite is the major magnetic phase in the adjacent layers.The existence of greigite unambiguously indicates an anoxic environment.We tentatively interpreted that such an environment could be formed by the fast sea level changes,long-existing of the cold eddies during warm stages,or in a lake which might be related to locally tectonic uplifting.Therefore,the occurrence of the thick-layer greigite could supply a new perspective to paleoenvironmental or even tectonic studies.Magnetic minerals in sediments of the continental shelf are sensitive to environmental changes. Therefore, to determine the exact phases of magnetic minerals is the prerequisite to investigate the paleoenvironmental significances. In this study, a comprehensive rock magnetic investigation, coupled with mineralogical studies, was carried out on the long core NHH01 （with a length of 125.64 m） from the central continental shelf of the South Yellow Sea. Single-domain greigite was identified as the dominant magnetic carrier in sediments between 44.90 and 51.80 m, and terrigenous magnetite is the major magnetic phase in the adjacent layers. The existence of greigite unambiguously indicates an anoxic environment. We tentatively interpreted that such an environment could be formed by the fast sea level changes, longexisting of the cold eddies during warm stages, or in a lake which might be related to locally tectonic uplifting. Therefore, the occurrence of the thicklayer greigite could supply a new perspective to paleoenvironmental or even tectonic studies.

关 键 词：南黄海中部 沉积物 地质意义 古环境意义 识别 厚层 环境变化 磁性矿物 

分 类 号：P618.31[天文地球—矿床学]