青海纳日贡玛始新世—渐新世含矿斑岩体地球化学特征  

Geochemistry of the Eocene-ligocene porphyry in the Narigongma region,Qinghai

作　　者：周伟 王玉德[2] 曹德智[2] 王毅智[2] 王永文[2] 

机构地区：[1]中国建材地质勘查中心陕西总队,陕西西安710003 [2]青海省地质调查院,青海西宁810012

出　　处：《沉积与特提斯地质》2007年第4期99-105,共7页Sedimentary Geology and Tethyan Geology

基　　金：中国地质调查局1:25万治多县;杂多县幅区域地质调查

摘　　要：纳日贡玛一带的始新世—渐新世斑岩体多以不规则小岩株形式产出,由二长花岗斑岩组成;岩石化学类型为亚碱性的富钾钙碱性系列,SiO2、Al2O3、K2O、Na2O、LREE,Sr、Rb、Ba、Th、Ce、Mo、Cu、Au、Ag含量高,CaO、TiO2、HREE、Y、Yb、Cr、Sc、Co、Ni亏损。稀土分馏明显,Eu异常不明显。斑岩源岩为壳源,有洋壳物质的混染;其形成模式为陆内俯冲导致软流圈上涌,并向下地壳注入诱发下地壳物质熔融产生岩浆。The Eocene Oligocene ore-bearing porphyry occurs as irregular stocks in the Narigongma region, Qinghai. The porphyry is composed of monzonitic granite porphyry in the subalkaline K-rich calc-alkaline series, and characterized by higher contents of SiO2, Al2O3, K2O, Na2O, LREE and Sr, Rb, Ba, Th, Ce, Mo, Cu, Au and Ag, depletion in CaO, TiO2, HREE, Y, Yb, Cr, Sc, Co and Ni, and well-balanced the element Eu. The geochemical signatures shows that the porphyry may be derived from the continental crust contaminated by the oceanic crust, and initiated from the magmas created by the melting of the lower crust due to the upwelling of the rheosphere triggered by intracontinental subduction.

关 键 词：纳日贡玛 始新世-渐新世 斑岩 地球化学 青海 

分 类 号：P594.1[天文地球—地球化学]