西南极利文斯顿岛百耳斯半岛火山岩的同位素年龄

以Ｋ－Ａｒ稀释法和４０Ａｒ／３９Ａｒ阶段加热法对利文斯顿岛百尔斯半岛的熔岩和次火山岩测定了同位素年龄。新的年龄数据表明，该区火山活动在晚侏罗纪末即已开始，一直持续到晚白垩世，存在着三期火山活动的产物。侏罗纪末～早白垩世初的火山活动除有熔岩（１４６Ｍａ，１３７Ｍａ）喷出外，还发育有辉长岩侵入体（１３５Ｍａ）和辉绿岩岩墙（１２９Ｍａ）等次火山岩。安山岩（１１４Ｍａ）和石英斑岩（９４Ｍａ）则是早白垩世火山活动的结果。半岛东部具沉积夹层的玄武岩（７１Ｍａ）是区域上晚白垩世～早第三纪火山活动的代表。

ISOTOPIC AGE OF THE VOLCANIC ROCK IN BYERS PENINSULA, LIVINGSTON ISLAND,WEST ANTARCTICA

K Ar dilution and 40 Ar/ 39 Ar step heating methods have been chosen in dating the isotopic ages of the volcanic and intrusive rocks of Byers Peninsula, Livingston Island. According to the geochronological data obtained, there are three epoches of volcanic activities in studied area by the end of Late Jurassic to Late Cretaceous.The Late Jurassic-Early Cretaceous activity produced basaltic and basaltic andesitic lavas(146Ma,137Ma), followed by gabbro intrusion(135Ma) and aplite dyke (129Ma).The andesite lava (114Ma) and quartz porphyry (94Ma) are of Early Cretaceous age.The basaltic lava with thin intercalated sedimentary beds at lower part represents the Late Cretaceous-Early Tertiary igneous activity regionally.