浙江常山里山岭斑岩型铜矿床成岩时代及岩浆源区  

Petrogenic Age and Magma Source of Granite Porphyry in Lishanling Porphyry Cu Deposit in Changshan Area,Zhejiang Province

作　　者：王科强[1,2,3] 张德会[1,2] 朱玉娣[4] 付芬[1,2] 印贤波 王晨昇[6] 

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083 [2]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [3]北京东方燕京矿山工程设计有限责任公司,北京100070 [4]西南石油大学地球科学与技术学院,成都610500 [5]西藏金龙矿业股份有限公司,拉萨850000 [6]中国有色金属矿产地质调查中心,北京100012

出　　处：《吉林大学学报（地球科学版）》2016年第3期736-748,共13页Journal of Jilin University：Earth Science Edition

基　　金：国土资源部项目(201411024);国家自然科学基金项目(41373048)~~

摘　　要：浙江是非金属矿大省,金属矿特别是斑岩型矿床的研究亟待进行。本文以里山岭斑岩型铜矿床为研究对象,首次采用SHRIMP U-Pb对该岩体侵位时代进行精确限定,利用Sr-Nd同位素示踪含矿岩体的岩浆源区,不仅为浙江斑岩型矿床成因的深入研究增加了新资料,还对浙西下一步找矿勘探具有重要意义。浙江常山里山岭斑岩型铜矿床位于钦杭成矿带东段,受球川—萧山深断裂带控制。该矿床铜矿化主要赋存于花岗斑岩体中。含矿花岗斑岩为高硅、富碱、高分异、过铝质S型花岗岩。岩体的稀土分布型式右倾,整体呈"海鸥型",有明显负Eu异常。岩石亏损Sr、Ba等大离子亲石元素,富集Nb、Ta、Zr、Hf、Ti、Y、Yb等高场强元素。含矿花岗斑岩锆石SHRIMP U-Pb年龄为(131±2)Ma,为早白垩世构造-岩浆活动的产物,形成于中国东部岩石圈减薄背景。岩浆岩(^(87)Sr/^(86)Sr)i值为0.679 95~0.721 08,平均0.701 14。ε_(Nd)(t)值为-8.4^-5.8,平均-6.7。Sr-Nd同位素特征表明含矿花岗斑岩源区主要为地壳,兼有少量地幔物质的混染。Zhejiang is well known for its abundant non-metallic mineral resource,whereas is lack of research data on metallic deposits,especially on the porphyry deposits. The Lishanling porphyry Cu deposit has been chosen as a study object,the SHRIMP zircon U-Pb dating is applied to restrict the emplacement age of Lishanling granite porphyry. Sr-Nd isotope tracing is completed to study the origin of granite porphyry. The research result not only can enhance the study on ore genesis of porphyry deposits in Zhejiang,but also is vital important for further ore exploration in western Zhejiang. The Lishanling porphyry Cu deposit is located in the east of QinzhouHangzhou suture zone,and the copper mineralization occurs within the granitic porphyry. The ore-bearing porphyry is classified as the S-type granite with high silica, alkaili content, strong fractionation, and peraluminous characteristics. In the chondrite-normalized diagram,the REE patterns lean to the right,appears as a seagulls,the enrichment of LREE and negative Eu anomalies are abvious. The porphyry is rich in Nb,Ta,Zr,Hf,Ti,Y,Yb; and depleted of LILEs such as Sr and Ba. Zircon SHRIMP U-Pb age of ore-bearing granite porphyry is（ 131 ± 2） Ma,which proves that the porphyry was resulted from the Early Cretaceous tectonicmagmatic activity and formed in the tectonic background of lithospheric thinning in Eastern China. The orebearing porphyry has relative high value of I_（Sr）（ 0. 679 95 to 0. 721 08） and low ε_（Nd）（ t） value（- 8. 4 to- 5. 8）,with the average value of 0. 701 14 and- 6. 7 respectively. The ore-bearing granite porphyry mainly origin from crustal rock with a small amount of mantle contamination, which can be proved by the Sr-Nd isotopic characteristics.

关 键 词：斑岩型铜矿 花岗斑岩 SR-ND同位素 SHRIMP锆石U-PB年龄 浙江常山里山岭 

分 类 号：P597[天文地球—地球化学] P618.41[天文地球—地质学]