GRANITOID AND TECTONIC TRANSPORT
Zhao Chunjing Li Zhitong(Shenyang Institute of Geology and Mineral Resources)
Tectonic transport is considered as a common and important process in geologic-tectonic evolution. In the same way, the generation and evolution of granitoid bear the same implication.Lateral transport of granitoid was noted long ago. Our study on temporal and spatial distribution of granitoid in northern Northeast China under the leading conception of "tcctonogranite province" shows that the spatial distribution of tectonogranite delts is arranged regularily from the old One to the young one. This feature is particularly distinct with the Paleozoic tectonogranite belts in the jiamusi massif and its peripheral areas (Fig. 1). There appears perfectly a lateral transport of Paleozoic granitoid from the centre, the Jiamusi massif, to the peripheral active tectonic zones. This lateral transport is coincident with the migration of the active tectonic zones.Longitudinal transport of granitoid.In central Inner Mongol, an east-west zone of Early Paleozoic volcano-sedimentary rock series is accompanied by a granitoid bell extending from Geshaotu eastward to Bainaimiao (Fig.2).The two were main elements in Early Paleozoic Bainaimiao islandarc tectonic zone. The granitoids associated with Baoerhantu Group(Ob)and Bainaimiao Group (S1-2b) are arranged along the direction with age changing from old (O)to young (S2) and the chemical characters from acidic to intermediate-acidic .The sizes of them are small(about 10 km2)to 1arge(over 10 km2) and the position from Shallow. to relatively deep. The ratio Na2O/K2O is low towards the west and high towards the east. The content of K-feldspar is decreasing and Ca-feldspar (An) increasing toward east. The A/ CNK values are 1 ,094 and 0.912 for the graintes in the west and 0.957 for those in the east (Ta b . 1 ), indicating crust for originated materials were less In the east than in the west. The abundance of REE is between 55 and 150 ppni and then; are certain differences in REE distribution pattern and 5Eu value between the granitoids in the west and that in the east (Tab .2, F ig. 3) . These characteristics show the transport of paleozoic granitoids from the west to the east.In addition, the Indo-Chinese granitoid shows also a longitudinal tsansport character in the Mishan-Dongning- Tonghua-Benxi area of eastern Northeast China.In short, the teetonic transport of the granitoid is obvious and follows the tec-tonic migration from the uplift area towards seg area. The trace of the transport of granitic magmatism indicates the character of the development and evolution of plate iectonics, Therefore, the study of granitoid transport has theoritical and practical significance.