本文選題：大興安嶺南段 + 白音查干Sn礦床��； 參考：《巖石學(xué)報》2017年10期

【摘要】：白音查干礦床位于內(nèi)蒙古自治區(qū)西烏珠穆沁旗,是大興安嶺南段新發(fā)現(xiàn)的一處大型Sn多金屬礦床,也是該地區(qū)近些年來Sn礦找礦的重大突破。本文利用LA-ICP-MS鋯石U-Pb法首次測得與成礦有關(guān)的石英斑巖成巖年齡為141.7±0.8Ma至140.2±1.1Ma。這一年齡與區(qū)內(nèi)其他Sn多金屬礦床成礦巖體的成巖年齡范圍基本一致,說明大興安嶺南段與Sn成礦作用有關(guān)的花崗質(zhì)巖石主要形成于早白堊世(140Ma左右)。全巖主量、微量和稀土元素地球化學(xué)特征顯示,石英斑巖具有較高的SiO_2含量(70.99%~76.98%)、FeOT/(FeOT+MgO)值(0.90~0.97)、FeOT/MgO值(9.45~36.3)及10000×Ga/Al值(5.9~8.2)和較低的MgO(0.13%~0.18%)、TiO_2(0.10%~0.12%)及P2O5含量(0.02%~0.03%);稀土元素總量較低,配分模式呈輕稀土元素富集和明顯負(fù)δEu異常的特點;微量元素富集Rb、U、Ta、Nd、Hf等元素,虧損Ba、K、Sr、P、Ti等元素。以上這些特征均說明,石英斑巖具備A型花崗巖的特點。微量元素、全巖Nd同位素和鋯石Hf同位素結(jié)果顯示,巖石具有較高的εNd(t)(+3.6~+3.8)和εHf(t)(+8.2~+11.6)值以及年輕的二階段模式年齡(t_(NdDM2)為0.63~0.62Ga;t_(HfDM2)為0.67~0.45Ga),說明石英斑巖可能為幔源新生地殼物質(zhì)部分熔融的產(chǎn)物,并在巖漿演化過程中經(jīng)歷了結(jié)晶分異作用。結(jié)合區(qū)域地質(zhì)特征、成巖年代學(xué)、巖石地球化學(xué)和Nd-Hf同位素數(shù)據(jù)可知,大興安嶺南段晚中生代與Sn成礦作用有關(guān)的花崗巖以源區(qū)富含大量幔源新生地殼物質(zhì)為特點,主要形成于晚中生代軟流圈上涌所導(dǎo)致的巖石圈伸展的背景下。
[Abstract]:Baiyinchagan deposit is located in West Wuzhoumuqin Banner of Inner Mongolia Autonomous region. It is a large Sn polymetallic deposit newly discovered in the southern section of Daxing'an Mountains, and is also a major breakthrough in the prospecting of Sn deposits in this area in recent years. By using LA-ICP-MS zircon U-Pb method, the diagenetic ages of quartz porphyry related to mineralization are 141.7 鹵0.8 Ma to 140.2 鹵1.1 Ma for the first time. This age is basically consistent with that of other Sn polymetallic deposits in the area, indicating that granitic rocks related to Sn mineralization in the southern part of the Daxinganling Mountains were mainly formed in the early Cretaceous (about 140 Ma). The geochemical characteristics of total rock mass, trace amount and rare earth elements show that quartz porphyry has a higher SiOSt2 content (70.99g / 76.98%), Feot / (FeotMgO) value (0.900.97), Feot / MgO (9.45g / 36.3) and 10000 脳 Gap / Al (5.98.2) and lower MgO (0.130.18%), TiO2 (0.100.12%) and P2O5 (0.02o 0.03%), the total amount of REE is lower, The distribution pattern is characterized by light rare earth element enrichment and obvious negative 未 EU anomaly. These characteristics indicate that quartz porphyry has the characteristics of A-type granite. Trace elements, whole-rock ND isotopes and zircon HF isotopes show that, The rocks have higher 蔚 ND (t) (3.6-3.8) and 蔚 HF (t) (8.2 ~ 11.6) values and a young two-stage model age (t _ (NdDM2) is 0.63 ~ 0.62GafDM2 = 0.670.45Ga), which suggests that quartz porphyry may be the product of partial melting of mantle derived Cenozoic crustal material and undergo crystallization differentiation during magmatic evolution. Combined with regional geological characteristics, diagenetic geochronology, petrogeochemical and Nd-Hf isotopic data, the late Mesozoic granites associated with Sn mineralization in the southern Daxing'anling Mountains are characterized by a large amount of mantle derived Cenozoic crustal materials in the source area. It is mainly formed in the late Mesozoic lithospheric extension caused by the upwelling of the asthenosphere.
【作者單位】： 中國地質(zhì)調(diào)查局發(fā)展研究中心;中國地質(zhì)大學(xué)地球科學(xué)與資源學(xué)院;國土資源部礦產(chǎn)勘查技術(shù)指導(dǎo)中心;西烏珠穆沁旗銀漫礦業(yè)有限責(zé)任公司;中國地質(zhì)科學(xué)院礦產(chǎn)資源研究所;
【基金】：國家重點研發(fā)計劃(2017YFC0601506) 中國地質(zhì)調(diào)查局項目(DD20160052、DD20160017)聯(lián)合資助
【分類號】：P588.132;P618.2

【相似文獻(xiàn)】

相關(guān)期刊論文 前10條

1 王衛(wèi)星;龔慶杰;鄧軍;張改俠;吳發(fā)富;韓志偉;;河南嵩縣地區(qū)石英斑巖地質(zhì)與地球化學(xué)特征研究[J];地質(zhì)與勘探;2010年02期

2 馬t焧，

本文編號：2098925