THERMAL EVOLUTION AND ITS SIGNIFICANCE OF I-A TYPE GRANITOID COMPLEX - THE LAOSHAN GRANITOID AS AN EXAMPLE

To reconstruct the cooling process of compound granites in different u nits (phases) with Laoshan Granitoid as an example, the relationships between formation, emplacement of I-A type granitoid and variation in tectonic environment and uplift of the orogenic belt are discussed fro m the viewpoint of thermal evolution. Now it has been pointed out that the cooling rates presented by the whole spectral series from I-type to A-type granites tend to be gradually faster and faster. Probably, i t is a token of thermal evolution that the regional structural environ ment of the granites was converted from closed, compressive into open, tensile environment.