文档介绍：: .
第54卷 第2期 (The Fifth Geological Exploration Institute of Qinghai Province, Xfining 810003 , Qinght, China)
Abstract: Hlualong rock group is the basement rock of Na_nsha_n tectonic bett in Qinghl prov­
ince. Its formation age remains pa_perstudied the gneissic granodiorite, which
intruded into Hualong rock group, through petrology, chronology and
research shows that the rock has high SiQ and T\l2 O3 , and low K, P, Ti. The content of SiQ is
% , ofK2O, % , ofK2O/N 岂(), , of (N 岂 O + K2O), % , of MgO, i 32% ,
of Al?()3. 13. 68% , belonging to mid-K caic-alkaline and prenluminous secies. The content of raire
eurth elements is lower, 工REE being 253. 77X10 i The rock is enriched in LREE and depelet-
ed in HREE. The REE patterns show cightwurd incline and moderate negative Eu anomj^-
ly. Compared with the adjj^cent elements, the truce elements show encichment of LILE (Th, U,
收稿日期:2020-03-06 :修回日期： 2020-12-03
基金项目： 屮国地质调查局项H “青海省共和县东巴地区三幅1： 5万区域地质矿产调查”（ 121201130睨020） 。
作者简介： 吴树宽（ 1986 -） ， 男，硕士， •级_稈师， 从事区域地质调查及矿产勘查_作。E- miil: ******@126. com。20 西北地质 NORTHWESTERN GEOLOGY 2021 年
Ba） , evident depletlon ofK, P, Ti, and reaative depletlon of Rb, Sc. Zr and Hf were positive a-
rock has the characteristics of A-typegranite with the forming age of （701 士 63）
Ma. Combinedwith the geochemical characteristics and reglonal magmatic activity events, it is
held that the gneissic granodiosite was generat