摘要
小寺沟斑岩型铜钼矿产于华北板块北缘,其主体岩体类型为英云闪长岩和二长花岗岩类,矿物组合为斜长石+角闪石+石英+钾长石±黑云母±辉石+不透明矿物,岩性为钙碱性I型侵入岩。K-Ar法测得小寺沟岩体花岗斑岩年龄为(122.83±2.46)Ma。岩石主量元素具有高SiO2、Al2O3、Na2O、Mg#,低K2O、TiO2、MgO、CaO、P2O5特征。稀土元素具有负Eu异常不明显,低HREE和Y,轻、重稀土元素强烈分异特征。研究认为,小寺沟岩体与埃达克岩相似,其初始岩浆主要为加厚下地壳的部分熔融产物,即小寺沟埃达克岩为C型埃达克岩,其初始岩浆中可能还有部分地幔物质。小寺沟大型斑岩型铜钼矿的形成与埃达克岩的成矿专属性、华北板块北缘特殊构造环境密切相关。
The Xiaosigou porphyry deposit occurs in the northern margin of North China craton,which belongs to the East Circum-Pacific metallogenic domain.The Xiaosigou pluton is comprised of tonalite and monzonitic granite,which are both I-type granites,with the mineral assemblage being plagioclase＋ amphibole＋ quartz＋ potassium feldspar±biotite±pyroxene＋some opaque minerals.K-Ar dating of unaltered granite-porphyry yielded an age of（122.83±2.46） Ma.SiO2,Al2O3, Na2O and Mg^# are high whereas K2O,TiO2,MgO,CaO and P2O5 are relatively low.The Xiaosigou pluton is characterized by slightly negative to positive δEu anomalies,the lowness of HREE and Y,and the intense fractionation of LREE from HREE.These characteristics suggest that the Xiaosigou pluton is extremely similar to adakite.The primitive magma of the Xiaosigou pluton was derived from the partially melted lower crust as well as some mantle materials.The Xiaosigou large-size porphyry copper-molybdenum deposit is genetically in close connection with adakite and the tectonic environment of the northern edge of North China craton.
出处
《矿床地质》
CAS
CSCD
北大核心
2010年第3期517-528,共12页
Mineral Deposits
基金
科技部国家"十一五"科技支撑计划(2006BA01B07)
国家"973"计划前期研究专项(1007CB416608)的联合资助
关键词
地球化学
埃克达岩
斑岩
年龄
小寺沟
河北
geochemistry
adakite
porphyry
age
Xiaosigou
Hebei Province
