纳日贡玛斑岩钼铜矿床：玉龙铜矿带的北延--来自辉钼矿Re-Os同位素年龄的证据  

Narigongma porphery molybdenite copper deposit,northern extension of Yulong copper belt:evidence from the age of Re-Os isotope.

作　　者：王召林[1] 杨志明[1] 杨竹森[2] 田世洪[2] 刘英超[2] 马彦青[3] 王贵仁[3] 屈文俊[4] 

机构地区：[1]中国地质科学院地质研究所,北京100037 [2]中国地质科学院矿产资源研究所,北京100037 [3]青海省地质调查院,西宁810012 [4]国家地质实验测试中心,北京100037

出　　处：《岩石学报》2008年第3期503-510,共8页Acta Petrologica Sinica

基　　金：国家科技支撑计划项目(编号2006BAB01A08)“三江”北段铜、铅锌、银矿床综合评价技术开发与应用”资助

摘　　要：纳日贡玛钼(铜)矿床位于西南"三江"北段青海南部地区,构造上位于金沙江缝合带与班公湖-怒江缝合带所夹持的羌塘地体之上,该区是吸纳和调节印度-亚洲大陆碰撞应力应变的构造转换带;受印度-亚洲大陆斜向碰撞事件的影响,区内新生代构造变形异常复杂,至51Ma 以来,区内形成了一系列 NW-SE 向的逆冲断裂系统及走滑断裂系统,并伴有少量钾质岩浆活动;纳日贡玛斑岩钼(铜)矿床便产于新生代黑云母花岗斑岩及其接触带中。长期以来,由于缺少可靠的年代学数据,人们对纳日贡玛矿床的产出环境尚不清楚,与玉龙癍岩铜矿带的关系还比较模糊。为此,本文选取了纳日贡玛钼铜矿6件辉钼矿样品进行 Re-Os 同位素测年,结果给出了一条均方差为0.79的 Re-Os 等值线,其年龄为40.86±0.85Ma,这与玉龙斑岩铜矿代的成矿年龄基本一致,应为玉龙铜矿带的北延;较大的成矿带延长范围表明,在玉龙至纳日贡玛上千公里的范围内,仍有寻找大型斑岩铜(钼)矿床的巨大潜力。Narigongma molybdenite copper deposit locates at the south Qinghai province, which is the northern segment of Sanjiang in southwest China and is bounded to the north by the Jinshajiang sature and to the south by the Bangonghu-Nujiang sature. This area is a tectonic transfer belt, which absorbs and accommodates the stress and strain coming from the collision of India and Asia continents. Affected by this collision, the tectonic deformation in this area is very complicated. Since 51Ma, series of NW-SE trending thrust faults and strike-slip faults are formed, companying with potassic magma simultaneously. Narigongma porphyry molybdenite copper deposit is formed in Cenozoic biotite granite porphyry and its boundary with wall rocks. For absence of reliable aging data, the occurrence environment of the deposit is not known by people, and the relationship with Yulong porphyry copper deposit belt is blurry, 6 samples of molybdenite are taken from Narigongma molybdenite copper deposit to analyze for Re-Os isotope dating, yielding a Re-Os isochrone age of 40.86 ± 0.85 Ma （MSWD = 0.79）. This age is consistent with the mineralization age of the Yulong porphyry, and Narigongma should be the northern prolongation of Yulong copper belt. Large extension of metallogenic belt indicates that there is still a tremendous potential of finding a large porphyry copper （molybdenite） deposit in the region from Yulong to Narigongma.

关 键 词：青海 纳日贡玛 斑岩钼铜矿 RE-OS年龄 

分 类 号：P597.3[天文地球—地球化学] P618.65[天文地球—地质学]