本文選題：結(jié)晶分異作用 + 同化混染作用��； 參考：《地質(zhì)與勘探》2017年05期

【摘要】：呼德生巖體位于柴北緣造山帶歐龍布魯克微陸塊東南緣,侵位于古元古代金水口變質(zhì)巖群中。該巖體從中心到邊緣依次出現(xiàn)橄欖巖→輝石巖→輝長巖的巖相分帶特征,巖石主要類型有純橄巖、橄欖二輝巖和輝長巖,各巖石之間多為過渡接觸關(guān)系,鎳銅礦化主要賦存于輝石巖中。鋯石LAICP-MS U-Pb年代學(xué)研究表明,巖體形成年齡為425.2±5.8Ma,為柴北緣晚志留世-晚泥盆世后造山伸展階段巖漿作用的產(chǎn)物。巖石鎂鐵比值(m/f)為2.51~5.37,屬于鐵質(zhì)系列基性-超基性巖。各類巖石富集輕稀土元素(LREE)和大離子親石元素(Ba、Sr、Rb),而虧損高場強元素(Zr、Hf、Nb、Ta)。巖相學(xué)、礦物學(xué)及巖石地球化學(xué)研究表明巖漿在演化過程中發(fā)生了一定程度的結(jié)晶分異作用和同化混染作用。結(jié)合巖體形成年代及區(qū)域地質(zhì)資料,呼德生巖體應(yīng)形成于大陸邊緣伸展階段,原始巖漿在演化過程中經(jīng)歷了地幔流體的交代作用。通過對巖漿結(jié)晶分異程度及同化混染情況等方面的綜合評價,認為呼德生巖體具有良好的銅鎳硫化物礦床形成條件。
[Abstract]:The Hudesheng rock body is located in the southeastern margin of the Oulong Brook micro-continental block in the northern Qaidam orogenic belt and in the Gu Yuan ancient gold-water mouth metamorphic rock group. The lithofacies zonation of peridotite pyroxenite gabbro appears from the center to the margin. The main types of rock are pure olivine, peridotite and gabbro, and most of them are transitional contact relationship. Nickel copper mineralization occurs mainly in pyroxenite. The zircon LAICP-MS U-Pb chronological study shows that the formation age of the rock mass is 425.2 鹵5.8 Ma, which is the product of magmatism during the late Silurian and post-Devonian orogenic extensional stages in the northern margin of Qaidam. The ratio of mg / f is 2.51 ~ 5.37, which belongs to the basic-ultrabasic rocks of iron series. Various types of rocks are enriched with LREE) and large ion lithophile elements BaSrsrbn, while the high field strength elements are depleted. Petrographic, mineralogical and petrogeochemical studies indicate that the magma experienced a certain degree of crystallization differentiation and assimilation mixing during the evolution of magma. Based on the age and regional geological data of the formation of the rocks, the Hudesheng rock body should be formed in the continental margin extension stage, and the primitive magma experienced mantle fluid metasomatism during the evolution process. Based on the comprehensive evaluation of the degree of crystallization differentiation and assimilation of magma, it is considered that the Hudesheng rock body has good conditions for the formation of Cu-Ni sulfide deposits.
【作者單位】： 國土資源部巖漿作用成礦與找礦重點實驗室中國地質(zhì)調(diào)查局西安地質(zhì)調(diào)查中心;青海省核工業(yè)地質(zhì)局;
【基金】：國土資源部公益性行業(yè)科研專項項目(201511020) 國家自然科學(xué)基金青年基金項目(41603050;41602094) 中國地質(zhì)調(diào)查局“東昆侖銅鎳多金屬資源基地調(diào)查”二級項目(DD20160013)聯(lián)合資助
【分類號】：P587;P597.3;P611
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本文編號：1960912