POST-PLATFORM MOUNTAIN-AND BASIN-MAKING MODEL IN HAINAN ISLAND OF CHINA:GEOCHEMICAL CONSTRAINTS FROM IGNEOUS ROCKS
POST-PLATFORM MOUNTAIN-AND BASINMAKING MODEL IN HAINAN ISLAND OF CHINA: GEOCHEMICAL CONSTRAINTS FROM IGNEOUS ROCKS
摘要
Since the late Hercynian episode the crust in Hainan has entered the post-platform activation or the diwa stage in which it has undergone a process from compressive (collision) orogeny and up1ifting during the late Hercynian-Indosinian movements to block-faulting type mountain- and basin-making during the Yanshanian-Himalayan movements. It has been shown through researches of igneous rocks that a post-platform orogenic belt being of a greatly thickened continental crust was once formed in the Hainan area during the late Hercynian-lndosinian cyc1e. The taphrogeny starting in the late Yanshanian episode was a product at the stage of late orogenic extension under conditions of the mountain root with a thickness of about 60 km retained. At 1ast, the lower lithospheric delamination and the crustal de-rooting of the orogen caused Hainan and its neighboring areas to transform from the continenta1 type crustobody to the continental-margin-spreading type crustobody.
Since the late Hercynian episode the crust in Hainan has entered the post-platform activation or the diwa stage in which it has undergone a process from compressive (collision) orogeny and up1ifting during the late Hercynian-Indosinian movements to block-faulting type mountain- and basin-making during the Yanshanian-Himalayan movements. It has been shown through researches of igneous rocks that a post-platform orogenic belt being of a greatly thickened continental crust was once formed in the Hainan area during the late Hercynian-lndosinian cyc1e. The taphrogeny starting in the late Yanshanian episode was a product at the stage of late orogenic extension under conditions of the mountain root with a thickness of about 60 km retained. At 1ast, the lower lithospheric delamination and the crustal de-rooting of the orogen caused Hainan and its neighboring areas to transform from the continenta1 type crustobody to the continental-margin-spreading type crustobody.
