关键词: 西南极,乔治王岛,火山岩,~（40）Ar／~（39）Ar,K-Ar

Abstract:

The volcanic and intrusive rocks from the northern coast of King George Island have been firstly dated with 40 Ar/ 39 Ar dating technique, K Ar dilute and laser microarea 40 Ar/ 39 Ar isochron dating techniques. Systematically dated results provide that the volcanic activities in studied area lasted from Late Cretaceous to the end of Eocene epoch and the major eruptions occurred in Eocene. Northeastwards younging of rocks along the northern coast suggests a gradual migration of the volcanic centers in King George Island, which correspond to the regularly distributed time space pattern of the volcanic activities on the South Shetland Islands. The intrusive rock was formed later than the eruptive rocks, that implies the granodiorite was from the same magma resource as basaltic lava and underwent differentiation. These new datawith such high precision will give a great support either for collating and stipulating the stratigraphical time or to the research on tectonomagmatic process.