矿床地质2012，Vol.31Issue(4)：727-744,18.
西藏弄如日金矿床侵入岩锆石SHRIMP U-Pb年龄与地球化学特征
Zircon SHRIMP U-Ph age and geochemistry of intrusive rocks from Nongruri gold deposit, Gangdese, Tibet
摘要
Abstract
Located in the Riduo town, Maizhokunggar County of Tibet, the Nongruri gold deposit is an epithermal' Au-Sb deposit discovered for the first time in the eastern part of southern Gangdese metaliogenic belt. In this study, zircon SHRIMP U-Pb agc, whole-rock major and trace elements of K-feldspar granite and monzogranite porphyry of this deposit were analyzed. The zircon SHRIMP U-Pb dating of K-feldspar granite shows that the crystallization age is (66.6 + 0.7) Ma. The major element analyses show that the rock is enriched in silica and alkali (with the average SiO2 being 76.74%, ALK being 8.22 % and A/CNK>1.0), and can be classified as high-K calc-alkaline granite with peraluminous. Chondrite-normalized REE patterns are of the rightly-oblique type. The rock is enriched in LREE and LILE and depleted in HREE and HFSE in the primitive mantle normalized multi-element diagram, its∑REE is 66.31× 10-6, exhibiting obvious negative Eu anomalies and showing some characteristics of arc magmatic rocks. The crystallization age of monzogranite porphyry is (18.8 ±0.3) Ma. The major element analyses of the rock shows the enrichment of silica and alkali (with the average SiQ2, being 72.69%, ALK being 6.73% and A/CNK>1.0), and can be classified as high-K calc-alkaline peraluminous granite. Chondrite-normalized REE patterns are of the rightly-oblique type. In the primitive mantle normalized multi-element diagram, the rock is enriched in LREE and LILE and depleted in HREE and HFSE, its ∑REE is 77.33 × 10-6 and its La/Yb ratios are high (the average of (La/Yb)N being 18.53), thus showing some typical geochemical characteristics of adakite. Combined with regional geological characteristics, the authors hold that the Nongruri gold deposit was formed in post-collisional extension setting simultaneously with the ore-bearing porphyry intrusive event related to the south-north fault system and rift zone in Gangdese, thus being a product of epithermal system in the periphery of the PCDs (porphyry Cu deposits) system.关键词
地球化学/锆石SHRIMP年龄/弧岩浆/中新世斑岩/弄如日金矿/冈底斯/西藏Key words
geochemistry, zircon SHRIMP age, arc magmatic rock, Miocene porphyry, Nongruri gold deposit, Gangdese, Tibet分类
天文与地球科学引用本文复制引用
刘云飞,杨志明,谢玉玲,周平,杜等虎,李应栩,李秋耘,曲焕春,许博..西藏弄如日金矿床侵入岩锆石SHRIMP U-Pb年龄与地球化学特征[J].矿床地质,2012,31(4):727-744,18.基金项目
本文得到行业基金项目"中国大陆环境典型斑岩型矿床成矿规律和找矿模式"(编号:2010011011)、国家重点基础研究发展计划(973计划)"青藏高原南部大陆聚合和成矿作用"(编号:2011CB403100)和中国地质调查局地质调查项目"青藏高原碰撞造山及成矿地质背景研究"(编号:1212011121253)的联合资助 （编号:2010011011）
