中生代以來華南地區之熱歷史及大地構造演化研究(1/3)

The Yanshanian (Jurassic and Cretaceous)
granitoids of South China cropout over an
immense area. The temporal and spatial
variation of granitoids in South China reveals
that the mid- to late-Jurassic (Early
Yanshanian 190-140 Ma) rocks are exposed
largely in the inland, whereas the early to
mid-Cretaceous (Late Yanshanian 130-90 Ma)
rocks are restricted to a narrow zone close to
the southeastern coast. Ages of intrusive
rocks along with tectonic thermal history
indicate that syn-orogenic high-Al, low-K
gabbroic intrusions (130-110 Ma),
post-orogenic high-K calc-alkaline granitic
magmatism (110-99 Ma) and anorogenic
basaltic volcanism (94-55 Ma) have
superimposed on the Cathaysia metamorphic
basement. We suggest that such a magmatic
evolution was a reflection of mountain
building to collapse tectonics in the maritime
Cathaysia. Moreover, the magmatism
triggered the thermal event which affected
regional thermal evolutionary history.