龙王(石童)A型花岗岩地质矿化特征

东秦岭北侧的华北古陆块南缘,发育一条碱性岩和碱性花岗岩带。龙王碴碱性花岗岩是该带中的一个典型的A型花岗岩体,岩石富含K、Na,缺Mg、Ca,多Fe少Al和水,含有碱性暗色矿物和很高的F及稀土元素,形成于非造山环境,属板内花岗岩。成岩时代为晋宁期(1035Ma,Rb-Sr)。龙王(石童)A型花岗岩的发现和厘定,证明华北地台南缘在中上元古代存在一个拉张的裂谷系。

THE GEOLOGICAL CHARACTERISTICS OF LONGWANG ZHUANG A-TYPE GRANITE AND ITS SIGNIFICANCE

Along the southern margin of North China old block at the northern side of the east Qing-ling there is an alkaline rock zone. Longwang Zhuang alkaline granite is the largest one of A-type granites in this zone. It is rich in K, Na and Fe and poor in Ca, Mg, Al and water, the confents of F and REE are also high. It is characterized by alkaline dark minerals appearing in Longwang Zhuang granite. It is nonorogenic granite within plate. The age of the granite dated to Jinning period (1035Ma by Rb-Sr method)oThe discovery of Long Wang Zhuang A-type granite and its study shows that there was a tensile rift system which occurred along the southern margin of the Northern China plateform in the middle or late Proterozoic which provides a prospecting area for the raremetals and rare-earth element deposits.