摘要
用放射化学和仪器中子活化分析,研究了浙江长兴二叠系/三叠系(P/T)界线剖面中29种元素的丰度分布。结果表明,界线粘土层的铱、锇、铂、金和铼,以及一些亲铁和亲硫元素都有程度不同的富集。在考虑了各种可能存在的地内因素后,类似于白垩纪末的地外物质撞击的可能性变得颇有吸引力。然而,Ir/Os和Ir/Au等元素丰度比值与太阳丰度比不符,有可能是二亿三千万年以来这些元素在风化过程中不同的地球化学行为所致。元素丰度的一些特征还有待深入研究。对长兴P/T界线的划分也作了适当讨论。
The abundance patterns of 29 elements at a Permina-Triassic boundary section,Changxin,Zhejiang,China were studied by RNAA and INAA.The results show that Ir,Os,Pt,Au,Re and other siderophile and chalcophile elements are more or less enriched at the boundary.After excluding various terrestrial factors,the possibility of the impact event of extraterrestrial body,similar to that at the end of the Cretaceous,becomes attractive.However,the ratios of Ir/Os and Ir/Au do not agree with the solar value,which may be caused by a long-term weathering process.Some abundance characters remain to be further studied.The boundary position of P/T,Changxin,was also discussed.
作者
柴之芳
马淑兰
毛雪瑛
孙亦因
徐道一
张勤文
杨正宗
Chai Chifang;Ma Shulan;Mao Xueying;Sun Yiying;Xu Daoyi;Zhang Qinwen;Yang Zhengzong(Institute of High Energy Physics,Academia Sinica;Institute of Geology,Academia Sinica;Institute of Geology,State Seismological Bureau;Institute of Geology,Chinese Academy of Geological Sciences;Beijing Astronomical Observatory,Academia Sinica)
出处
《地质学报》
1986年第2期139-150,共12页
Acta Geologica Sinica
基金
中国科学院科学基金会,地准字275号。
