华南基底变质岩的Sm-Nd同位素及其对花岗岩类物质来源的制约

Sm-Nd ISOTOPIC STUDY OF BASEMENT METAMORPHIC ROCKS IN SOUTH CHINA AND ITS CONSTRAINT ON MATERIAL SOURCES OF GRANITOIDS

华南地区存在两种类型变质基底。Sm-Nd同位素数据的研究结果表明,它们可分别代表华南两种类型元古代地壳端员。华夏地块区副变质岩代表成熟度较高的(早)元古代地壳端员,^(147)Sm/^(144)Nd=0.1198,^(143)Nd/^(144)Nd=0.511822;江南古岛弧区副变质岩代表成熟度较低的(中—晚)元古代地壳端员,^(147)Sm/^(144)Nd=0.1246,^(143)Nd/^(144)Nd=0.512170。根据上述数据得出了华南元古代地壳Sm-Nd同位素演化域,进而对华南不同时代花岗岩类的物质来源作了进一步的讨论。

There exist two types of metamorphic basements in South China. The results of Sm-Nd isotopic study indicate that they represent the two types of Proterozoic crustal endmember. The parametamorphic rocks in the Cathayia Massif represent the(Early)Proterozoic crustal endmember of higher degree of maturation with ^(147)Sm/^(144)Nd=0.1198 and ^(143)Nd/^(144)Nd=0. 511822, while those in the Jiangnan Paleo-island-arc represent the(Middle—Late)Proterozoic crustal endmember of lower degree of maturation with ^(147)Sm/^(144)Nd=0.1246 and ^(143)Nd/^(144)Nd =0.512170. Based on the above-mentioned data, the Sm-Nd isotopic evolution region of the Proterozoic crust in South China has been obtained, and the material sources of granitoids in this region have been interpreted.