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.
出处
《南极研究》
CSCD
1991年第2期126-135,共10页
关键词
火山岩
同位素年代
地层
南极
Fildes Peninsula, isotope age, correlation of stratigraphy.
