关键词: 原地重熔, 珠江口盆地, 花岗岩, 披覆背斜, 二次生烃

Abstract:

The analysis of the geochemical and geophysical characteristics of Yanshan Period granite in the Pearl River Mouth Basin suggested that the uplifting of the lithosphere isothermal surface and multiple melting of the upper crust, which resulted from the subduction of the Pacific plate under the South China plate, gave rise to the formation of the granite. The granite dome and drape anticline on the uplifting part of the basin was formed by the regional erosion and the sedimentation in the Cenozoic afterwards. The drape anticline was one of the most important tectonic types of oil and gas bearing structure in Pearl River Mouth Basin. The Dongsha Rise and its northern region are characterized by hightemperature geothermal field in the Mesozoic and the granite, while the southern depression is featured by lowertemperature geothermal field and the Mesozoic sedimentary. Owing to the low thermal evolution of source rock in the southern depression, there was a possibility that secondary hydrocarbon generation could occur in the Cenozoic.

Key words: insitu melting, Pearl River Mouth Basin, granite, drape anticline, secondary hydrocarbon generation