摘要
努日超大型多金属矿床是近年来冈底斯成矿带发现的首例白钨矿矿床,通过对矿区不同产状、岩性的岩浆岩开展主量元素、微量元素、稀土元素、锆石U-Pb年代学、Re-Os同位素、Sr-Nd-Pb-Hf同位素等综合研究,研究结果表明:努日矿区岩浆岩演化序列为石英闪长玢岩(93.42±0.76Ma)→安山岩(92.04±0.71Ma)→黑云母花岗岩(50.46±0.56Ma)→花岗闪长斑岩(24.83±0.21Ma),从高钾钙碱性到钙碱性系列均有分布,其中石英闪长玢岩含SiO_257.19%～58.23%,K2O1.71%～2.2%,总碱含量高(5.28%～5.77%),含Al_2O_314.14%～16.45%,CaO含量中等(2.33%～4.11%),里特曼指数(σ)为1.79～2.07,铝指数(A/CNK)为0.77～0.82,Mg#指数47.19～49.51,岩石富集大离子亲石元素Rb、U、Pb、Ba、Th,轻重稀土分异明显,LREE/HREE为10.25～11.07,具有弱的Ce异常,相对较低的87 Sr/86 Sr初始比值(0.7039～0.706),具有埃达克岩特征;安山岩含SiO_254.17%～60.27%,K2O 1.78%～2.25%,Al_2O_317.89%～22.65%。里特曼指数σ为1.32～2.34,铝指数(A/CNK)为0.91～1.54、Mg#指数48.14～52.04,岩石富集大离子亲石元素Rb、U、Ba、Th,轻重稀土分异明显,LREE/HREE为9.86～16.94,具有明显的的Eu负异常,为正常岛弧岩浆岩特征;黑云母花岗岩含SiO_264.90%～66.12%,K2O 2.31%～23.86%,总碱含量高(6.47%～7.01%),含Al_2O_315.52%～16.15%、CaO含量中等(2.33%～4.11%),里特曼指数σ为1.45～2.17,铝指数(A/CNK)为0.93～1.02,Mg#指数28.49～36.55,岩石富集大离子亲石元素Rb、U、Pb、Ba、Th,轻重稀土分异明显,LREE/HREE为6.26～7.29,具有强的Eu负异常,小于大陆地壳值的87Sr/86Sr初始比值(0.704488～0.704584),具有岛弧岩浆岩特点;花岗闪长斑岩含SiO_259.12%～74.97%,K2O 0.83%～3.67%,总碱含量高(2.77%～6.89%),含Al_2O_3 11.31%～17.06%、CaO含量中等(5.32%～6.22%),里特曼指数σ为0.24～2.64,铝指数(A/CNK)为0.75～0.93,Mg#指数35.11～51.57,岩石富集大离子亲石元素Rb、U、Ba、Th,轻重稀土分异明显,LR
The Nuri superlarge polymetallic deposit is the first scheelite deposit recently found in the Gangdese metalloginic belt.Based on the geological suvery,this study carried out geochemical analysis,zircon U-Pb chronolgy,Re-Os isotope and Sr-Nd-Pb-Hf isotope for the magmatic rocks in the mining area.The results show that the magma sequence evolved from quartz diorite porphyrite（93.42＋0.76 Ma）,to andesite（92.04＋0.71 Ma）,biotite granite（50.46＋0.56 Ma）,granodiorite-porphyry（24.83＋0.21 Ma）,suggesting an evolution from the high potassium calc-alkaline to calc-alkaline series.Quartz diorite porphyrite has SiO2 of（57.19%～58.23%）and K2 O of（1.71%～2.2%）,high total alkalinity of（5.28%～5.77%）,Al2O3 of（14.14%～16.45%）and medium CaO of（2.33%～4.11%）.It is also characterzied by Rittmann index of（1.79～2.07）and A/CNK of（0.77～0.82）,Mg#values of 7.19～49.51,enrichment in Rb,U,Pb,Ba and Ths;LREE/HREE of（10.25～11.07）,enrichment in LREE relative to HREE,and weak Ce anomaly,lower（87 Sr/86 Sr）t of（0.7039～0.706）,suggesting that quartz diorite porphyrite is characterisitc of adakite.Andesite contain SiO2（54.17% ～60.27%）,K2 O（1.78% ～2.25%）,Al2O3（17.89%～22.65%）,and Rittman valueσ（1.32～2.34）,A/CNK（0.91～1.54）,Mg#（48.14～52.04）.It also enriches in Rb,U,Ba and Th,and distinct differentiation of LREE and HREE with LREE/HREE（9.86～16.94）and obvious Ce anomaly,suggesting the feature of normal island-arc magmatic rocks.Biotite granite contains the SiO2（64.90%～66.12 %）,K2 O（2.31%～23.86%）,total alkalinity（6.47%～7.01%）and Al2O3（15.52%～16.15%）and CaO（2.33%～4.11%）,theσ（1.45～2.17）,A/CNK（0.93～1.02）,Mg#（28.49～36.55）,enrichment of Rb,U,Pb,Ba and Th,and the LREE/HREE（6.26～7.29）and obvious Eu anomaly,and（87 Sr/86 Sr）t（0.704488～0.704584）,suggusting the feature of island-arc magmatic rocks.Granodiorite-porphyry contains SiO2（59.12% ～74.97%）and K2 O（0.83%～3.67%）,high t
作者
闫国强
王欣欣
黄勇
刘洪
黄瀚霄
田恩源
赖杨
赵晋
YAN Guoqiang;WANG Xinxin;）;HUANG Yong;LIU Hong;HUANG Hanxiao;TIAN Enyuan;LAI Yang(）Tianjin Center,China Geological Survey,Tianjin,300170;）Institute of Coal Engineering,Datong University,Datong,037003;）No.217 Geological Party,Datong,037008;）Chengdu Center,China Geological Survey,Chengdu,610081;）Institute of mineral Resources Muti-Utilization,Chengdu,610041)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2018年第10期2138-2154,共17页
Acta Geologica Sinica
基金
国家深地资源专项(2016YFC0600308)
国家重点研发计划(2016YFC0600308)
中国地质调查项目(DD20160015)
国家自然科学基金(41702086)联合资助的成果
关键词
岩浆演化
多期成矿
区域成矿作用
努日
西藏
magma evolution
mutilphase mineralization
regional mineralization
Nuri
Tibet
