九龙脑岩体矿物学研究及其对岩浆演化和成矿作用的指示意义

发布时间：2018-02-02 06:43

  本文关键词： 矿物化学 岩石成因 成矿作用 九龙脑矿田 花岗岩　出处：《地学前缘》2017年05期 　论文类型：期刊论文

【摘要】：九龙脑岩体位于南岭成矿带东段崇余犹矿集区内,是由四个期次花岗岩组成的复式岩体,从早到晚分别为中粗粒黑云母花岗岩(γ2-1a5)、中粗粒斑状(含白云母)黑云母花岗岩(γ2-1b5)、细-中细粒斑状黑云母花岗岩(γ2-2a-2b5)、细-中细粒(含黑云母、石榴石)花岗岩(γ25),以其为中心,钨锡、金银铜铅锌、铀、铌钽等多矿种、多期次、多成因矿床分带产出。通过对花岗岩的矿物学研究,确定九龙脑花岗岩中的钾长石以正长石为主,斜长石为钠-更长石,黑云母为富铁黑云母-铁叶云母-铝铁叶云母,原生白云母较次生白云母具有高铁、锰、镁、氟、氯和低铝特征,石榴石属于锰铝榴石-铁铝榴石,绿泥石为鲕绿泥石-蠕绿泥石(铁绿泥石)-铁镁绿泥石,副矿物中常含微量的稀有金属元素。原生白云母和钛铁矿的存在以及黑云母矿物化学特征指示九龙脑花岗岩为S型花岗岩。第一期次花岗岩结晶时具有较高的氧逸度,其黑云母结晶温度为550~600℃;第二、三、四期次花岗岩结晶时具有相对较低的氧逸度,其黑云母结晶温度分别为600~700℃、600~700℃、550℃。第一、三、四期次花岗岩中绿泥石的形成温度分别为385~400℃、300~370℃、359~397℃,显示九龙脑花岗岩经历了中高温热液流体的影响。矿物化学特征表明,九龙脑花岗岩与南岭地区成钨锡钼铋矿的花岗岩具有相似的矿物组成,第一期次、第二期次、第四期次花岗岩可能与矿田内丰富的钨、锡、铌钽、铀矿化密切相关。
[Abstract]:The Jiulongnao rock body, located in the Chongyu ore concentration area of the eastern section of the Nanling metallogenic belt, is a complex rock body consisting of four sub-granites, from early to late, it is a medium-coarse biotite granite (纬 _ 2-1a _ 5). Medium-coarse porphyry (including Muscovite) biotite granite (纬 2-1b5U), fine-grained porphyry biotite granite (纬 2-2a-2b5U), fine-medium grained biotite (including biotite). Garnet) granites (纬 25s, centered around it, with tungsten, tin, gold, silver, copper, lead and zinc, uranium, niobium and tantalum, etc. It is determined that the potassium feldspar is mainly orthoclase, the plagioclase is sodium-feldspar, the biotite is iron-rich biotite-iron leaf mica-aluminopite, and the primary Muscovite has higher iron and manganese than secondary Muscovite. The characteristics of magnesium, fluorine, chlorine and low aluminum are that garnet belongs to manganese aluminite-iron aluminite, and chlorite is oolitic chlorite-vermicular chlorite (iron chlorite-iron magnesium chlorite). The presence of primary Muscovite and ilmenite, as well as the chemical characteristics of biotite minerals, indicate that the Jiulongnao granite is S-type granite. Fugacity. The crystallization temperature of biotite is 550 鈩，

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