本文關(guān)鍵詞： 鈣矽卡巖 電子探針 維寶礦床 新疆 祁漫塔格　出處：《地質(zhì)學(xué)報(bào)》2017年05期 　論文類型：期刊論文

【摘要】：維寶矽卡巖銅鉛鋅礦床位于新疆與青海兩省交界處,大地構(gòu)造位置屬祁漫塔格造山帶東段,可以分為維東、主礦段和維西三個礦段。主礦段和維東礦段以鉛鋅礦化為主,銅礦化很少,而維西礦段銅、鉛、鋅礦化均較發(fā)育。本次我們選取維西礦段的矽卡巖和礦石樣品,進(jìn)行了詳細(xì)的礦物學(xué)研究。根據(jù)礦物共生組合、礦石組構(gòu)以及脈體的穿插關(guān)系,可以將維西礦段成礦過程分為4個階段,即早期矽卡巖階段、晚期矽卡巖階段、石英-硫化物階段和石英-碳酸鹽階段,其中石英-硫化物階段是主要的成礦階段。矽卡巖礦物主要為石榴子石、輝石、綠簾石和角閃石等,硫化物主要為黃銅礦、方鉛礦、閃鋅礦、黃鐵礦和磁黃鐵礦等。電子探針分析表明,石榴子石成分以鈣鐵榴石分子(And=59.00%～97.70%)和鈣鋁榴石分子(Gro=1.92%～40.42%)為主,為鈣鐵—鈣鋁系列石榴子石;輝石主要由透輝石分子(Di=45%～91%)和鈣鐵輝石分子(Hd=8%～53%)組成,表現(xiàn)在礦物上以透輝石為主,而鈣鐵輝石數(shù)量很少;角閃石成分變化范圍比較大,但總體上為透閃石—陽起石系列。綜合礦物組合和化學(xué)成分特征表明維寶礦床維西礦段矽卡巖為鈣矽卡巖。此外,具有環(huán)帶結(jié)構(gòu)的石榴子石從核部到邊部,化學(xué)成分表現(xiàn)出有規(guī)律的變化,Al2O3含量先上升后下降,FeOT含量則先下降后上升。這表明隨著交代作用的進(jìn)行,成礦流體的pH值不斷發(fā)生變化,由最初的弱酸性—堿性條件轉(zhuǎn)變?yōu)榻行詶l件,最終又恢復(fù)到弱酸性—堿性條件。維西礦段硫化物的金屬原子與硫原子的比值大部分都大于理論值,表明它們形成于硫逸度較高的環(huán)境。此外,閃鋅礦中Fe、Zn含量變化范圍比較大,Zn=54.50%～64.75%,Fe=1.15%～10.16%,這種大范圍變化指示成礦過程中溫度和硫逸度可能發(fā)生波動。
[Abstract]:The Weibao skarn copper-lead-zinc deposit is located at the junction of Xinjiang and Qinghai provinces. The geotectonic position belongs to the eastern section of the Qimantage orogenic belt, which can be divided into three ore segments: Weidong, main ore and Weixi. The main ore segment and Weidong ore section are mainly lead-zinc mineralization. Copper mineralization is rare, but copper, lead and zinc mineralization are relatively developed. In this paper, we selected skarn and ore samples from Weixi ore section to carry out detailed mineralogical study. According to the mineral symbiotic assemblage, The ore-forming process of Weixi formation can be divided into four stages: early skarn stage, late skarn stage, quartz-sulfide stage and quartz-carbonate stage. The quartz-sulfide stage is the main metallogenic stage. Skarn minerals are mainly pomegranate, pyroxene, verdanite and hornblende, while sulfides are chalcopyrite, galena, sphalerite, etc. Electron probe analysis of pyrite and pyrrhotite shows that the main components of pomegranate are calc-iron eclogite molecule And59.00 (97.70) and calcium aluminoeclogite molecule Gros1.92 and 40.42%, which are mainly calcium ferrium-calcium aluminum-series garnet. The pyroxene is mainly composed of diopside molecule Dixene 45 and Calciferopyroxene molecule Hdf8. The pyroxene is mainly diopside in minerals, but the quantity of calcium ferroxene is very small, and the amphibole composition has a relatively large range of changes. But in general, it is tremolite-actinolite series. The comprehensive mineral assemblage and chemical composition characteristics indicate that skarn is calcium skarn in Weixi formation of Weibao deposit. In addition, the garnet with annular structure is from the core to the edge. The chemical composition showed a regular change. The content of Al _ 2O _ 3 increased first, then decreased and then increased. This indicated that the pH value of the ore-forming fluid changed continuously with the metasomatism. From the initial weak acidic to basic condition to the near neutral condition, and finally to the weak acidic basic condition, the ratio of metal atom to sulfur atom in the Vesi ore section is mostly larger than the theoretical value. The results show that they are formed in the environment with high sulfur fugacity. In addition, the variation range of Fe ~ (2 +) Zn content in sphalerite is larger than that of Zn ~ (2 +) 54.50 ~ 64.750.10 ~ (16), which indicates that the temperature and sulfur fugacity may fluctuate during the metallogenic process.
【作者單位】： 中國地質(zhì)科學(xué)院礦產(chǎn)資源研究所國土資源部成礦作用與資源評價重點(diǎn)實(shí)驗(yàn)室;
【基金】：國土資源部公益性行業(yè)科研專項(xiàng)經(jīng)費(fèi)項(xiàng)目(編號201411025) 中國地質(zhì)調(diào)查局地質(zhì)調(diào)查項(xiàng)目(編號1212011085528;12120113093600);中國地質(zhì)調(diào)查局高層次地質(zhì)人才培養(yǎng)計(jì)劃(編號201309)和青年地質(zhì)英才計(jì)劃(編號201112)資助的成果
【分類號】：P618.4

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