胶西北寺庄金矿床流体—岩石反应过程与金成矿机制

发布时间：2018-08-14 09:19

【摘要】：寺庄金矿床是近年勘查探明的位于胶东金矿集区焦家金矿带最南端的一个超大型蚀变岩型金矿床,矿体全部产于蚀变带内,然其流体-岩石反应过程与金成矿机制尚未查明。为此,论文通过系统的野外和室内研究,厘定了该矿床矿化类型和蚀变分带,查明了其蚀变-矿化时空结构,探讨了其金成矿机制,获得如下主要认识:(1)蚀变类型有钾长石化、绢英岩化、黄铁绢英岩化和碳酸盐化,矿化类型有蚀变岩型、过渡类型和石英脉型。(2)蚀变矿化具有分带性,主裂面向外依次发育黄铁绢英岩带→绢英岩化带→钾长石化带→玲珑黑云母花岗岩带,对应矿体依次为蚀变岩型→过渡类型→石英脉型→无矿体。蚀变矿化具有多次脉动、叠加的特点,从早到晚依次为钾长石化→绢英岩化和黄铁绢英岩化,伴随蚀变岩型矿化→石英脉型矿体形成→碳酸盐化。(3)蚀变岩质量平衡计算指示钾长石化过程Si O2、Al2O3、Fe2O3、Fe O、Mg O、Na2O、Au、Ag、As、Hg、Pb及稀土元素迁出,K2O迁入;(黄铁)绢英岩化过程Si O2、Fe2O3、Fe O、K2O、Au、Ag、As、Hg、Cu、Sb、Bi及轻稀土迁入,Al2O3、Na2O及重稀土迁出。黄铁绢英岩化过程Au变异系数14073.49%,是绢英岩化过程的16倍,钾长石化过程的283倍。(4)二长石温度计法计算指示钾长石化形成温度为349~449℃,钾长石化花岗岩稀土元素显示正铕异常,指示钾长石化发生在氧化环境下;流体包裹体显微测温指示成矿温度集中于200~300℃,矿石稀土元素显示负铕异常,指示成矿发生在还原环境下。根据矿物组合以及金与硫、氯的相关性,推断金以金-硫络合物的形式迁移,绢英岩化和黄铁绢英岩化过程中石英和黄铁矿的沉淀破坏了金-硫络合物的稳定保存条件,使得金从热液中沉淀出来。
[Abstract]:The Sizhuang gold deposit is a super-large altered rock type gold deposit located at the southernmost end of Jiaojia gold belt in Jiaodong gold concentration area, which has been discovered in recent years. The orebody all occurs in the altered zone, but its fluid-rock reaction process and gold metallogenic mechanism have not been clarified. Therefore, through systematic field and laboratory studies, the mineralization types and altered zones of the deposit are determined, the time-space structure of alteration and mineralization is found out, and the mechanism of gold mineralization is discussed. The main conclusions are as follows: (1) the alteration type is potassium feldspathic. The types of mineralization are altered rock type, transition type and quartz vein type. (2) alteration mineralization is zonation. The main fracture faces to the outside and develops in turn the Yulinglong biotite granite belt along the kalium-feldspar lithochemical belt, corresponding to the altered rock type and transition type, quartz vein type and no ore body. Alteration mineralization has the characteristics of multiple pulsation and superposition. From early to late, the order of alteration mineralization is kalitization and yellowtigitization. The mass balance calculation of altered rocks indicates that Sio _ 2o _ 2AL _ 2O _ 3n Fe _ 2O _ 3O _ 2O _ 3 Fe _ 2O _ 3H _ 2O _ (O) O _ (2) O _ (2) O _ (2) O _ (2) O ~ (2 +) O ~ (2 +) O _ (2) O ~ (2 +) O ~ (2 +) O ~ (2 +) O _ (2) O _ 2O _ (3) Fe O _ 2O _ (3) Fe O _ (2) O _ 2 O _ 2 O _ (2) O _ (2) O _ 2 O _ (2) O _ (2) O _ (2) O _ (2) O _ 2 O _ (2) O _ (2) O _ (2) O _ The soil migrated to Al _ 2O _ 3, Na _ 2O and heavy rare earth. The coefficient of variation of au is 14073.49, which is 16 times of that of sericolith and 283 times of that of potassium feldspar. (4) the formation temperature of potassium feldspar is 349 ~ 449 鈩，

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