ON THE PRINCIPLES AND METHODS FOR ESTABLISHING GRANITIC SUITES （SEQUENCES） IN SOUTHERN CHINA

The problem of granite is essentially a regional one. The granitic suite is a concept proposed from the view-point of regional petrology on the basis of the study of regional geology. Taking for example the granites in southeastern Hubei, the southern Jiangxi-southern Hunan-northern Guangdong region and the Fujian-Zhejiang coasts, the paper dealts with the principles and methods for the division of granitoids into suites. In southeastern Hubei, the Yanshanian granitoids belong to I-type granite. The magmatic activity involved four older to younger suites. Each suite is characterized by a rhythm of evolution from intermediate to acid rocks, and in each next rhythm the proportion of acid rocks become progressively larger with time. The duration of each suite is about 10--20Ma. The early Yanshanian granitoids in the southern Jiangxi-southern Hunan- northern Guangdong region belong to S-type gtanite. The magmatic activity in the whole region was in the main concerned with one suite. Although this suite also exhibits the law of evolution from intermediate to acid rocks, it is more acid than the granitoids in southeastern Hubei. The range of rock com- position of the suite is quite narrow. The duration of the suite is about 40-- 50Ma. The late Yanshanian atkaline-slightly alkaline miarolitie granitoids along the Fujian-Zhejiang coasts belong to A-type granite and are usually intima- tely associated with alkaline granitoids, both combining to form a suite in which the riebekite granite is the latest product. The duration of the suite is at least greater than 20Ma. From above it may be recognized that the granitoids of southern China not only can be divided into suites, but granitoids of different origin also pos- sess different granitic suites, which implies that they were derived from different sources. Finally, this paper presents a series of field indications for the study of the contact relationships within the intrusions, distinction between intrusions of different ages within a batholith and establishment of the sequence of magmatic activity.