西南极乔治王岛菲尔德斯半岛火山岩同位素年代及地层对比  

THE ISOTOPE AGE OF THE VOLCANIC ROCKS AND THE CORRELATION OF STRATIGRAPHY IN THE FILDES PENINSULA, KING GEORGE ISLAND, WEST ANTARCTICA

作　　者：朱铭[1] 鄂莫岚[1] 刘小汉[1] 郑祥身[1] 

机构地区：[1]中国科学院地质研究所,北京100029

出　　处：《南极研究》1991年第2期126-135,共10页

摘　　要：以K-Ar,(39)~Ar-(40)~Ar和Rb-Sr法对菲尔德斯半岛的火山岩进行了同位素测年。实验结果表明,半岛的火山作用从晚古新世开始,可能一直延续至中中新世的早期。其间,碧玉山段的岩石分别以Rb-Sr和(39)~Ar-(40)~Ar法测定了形成年龄,年龄值为54Ma和55Ma,属于晚古新世;岛上广泛分布的玛瑙滩段熔岩的K-Ar年龄区间为45～50Ma,为早始新世;化石山段从中始新世到渐新世;而最晚形成的岩块山段的时代为中中新世的早期。这些数据,与地质和古生物证据一起,对了解该区地层的相互关系和讨论火山作用提出了正确的认识。The ages of volcanic rocks from the Fildes Peninsula, King George Island, West Antarctica have been determined with K-Ar, 39Ar-40Ar, Rb-Sr methods by authors. The results show that: a. the age range of the volcanism in the Fildes Peninsula is from Later Paleocene to Early Mid-Miocene; b. the forming time of the volcanic rocks of Jasper Hill Member belonges to Later Paleocene because of the isotope ages being 54Ma and 55Ma determined with Rb-Sr and 39Ar - 40Ar, respectively; c. the volcanic rocks of Agate Beach Member are the products of the volcanic activities during Early Eocene period according to the isochron of K-Ar method (45-50 Ma); d. the geological age for Fossil Hill Member is about from Mid - Eocene to Early Oligocene, and e. the time formed the Block Hill Member lasts Early Mid - Miocene, probabley. These data combining with the geological and palaeozoological evidences have presented strong support for best understanduing the correlation of the stratigraphy and, discussing the volcanism in studied area.

关 键 词：火山岩 同位素年代 地层 南极 

分 类 号：P588.14[天文地球—岩石学]