CHEMICAL SPECIES OF IRIDIUM AND OTHER TRACE ELEMENTS IN THE CRETACEOUS-TERTIARY BOUNDARY CLAYS AND ITS IMPLICATION  

作　　者：孔屏 柴之芳 毛雪瑛 马淑兰 

机构地区：[1]Institute of High Energy Physics, Academia Sinica, Beijing 100080, China

出　　处：《Nuclear Science and Techniques》1991年第2期106-115,共10页核技术（英文）

基　　金：The Project Supported by National Natural Science Foundation of China

摘　　要：The geological samples: Cretaceous- Tertiary (K- T) boundary clays, meteorites, volcanic lava, and ultrabasic rock were separated into carbonate, metal, sulfide, oxide, silicate and acid- resistant residue by a selective chemical dissolution procedure developed in our laboratory. Some conclusions were drawn by analyzing the chemical speciation of anomalous iridium in the above samples and especially by studying the characteristics of mineral components in those residue phases. (1) It is impossible that the anomalous Ir was caused by geochemical enrichment; (2) The iridium enrichment in the K- T boundaries did not necessarily associate with kerogen; (3) The volcano activity has participated in the extinction event at the end of Cretaceous; (4) Extraterrestrial impact was the trigger of K- T event. Then, we proposed a mixed model by which the extant anomalous Ir in K- T boundary clays was interpreted as a combined effect of extraterrestrial impact, volcano eruption and post- depositional redistribution.The geological samples: Cretaceous- Tertiary (K- T) boundary clays, meteorites, volcanic lava, and ultrabasic rock were separated into carbonate, metal, sulfide, oxide, silicate and acid- resistant residue by a selective chemical dissolution procedure developed in our laboratory. Some conclusions were drawn by analyzing the chemical speciation of anomalous iridium in the above samples and especially by studying the characteristics of mineral components in those residue phases. (1) It is impossible that the anomalous Ir was caused by geochemical enrichment; (2) The iridium enrichment in the K- T boundaries did not necessarily associate with kerogen; (3) The volcano activity has participated in the extinction event at the end of Cretaceous; (4) Extraterrestrial impact was the trigger of K- T event. Then, we proposed a mixed model by which the extant anomalous Ir in K- T boundary clays was interpreted as a combined effect of extraterrestrial impact, volcano eruption and post- depositional redistribution.

关 键 词：IRIDIUM ANOMALY Chemical SPECIATION INSOLUBLE residue Spherule Transmission electron MICROSCOPE 

分 类 号：TL[核科学技术]