论拉尔玛金(铀)矿床热液隐爆机构及其与金成矿的关系  

ON THE CRYPTO-EXPLOSIVE CRATER AND ITS RELATION WITH GOLD MINERALIZATION IN LARMA Au-U DEPOSIT

作　　者：陈国华 景宏祥 黄树桃[2] 

机构地区：[1]金渠金矿,河南三门峡市472000 [2]核工业北京地质研究院,北京100029

出　　处：《铀矿地质》1998年第4期207-213,共7页Uranium Geology

摘　　要：在拉尔玛金铀矿床研究中鉴别出一种新的金矿控矿构造──热液隐爆机构。该机构在平面上呈近椭圆形，剖面上呈漏斗状，顶部为一由热液硅岩构成的“硅盖”，中心部位为热液隐爆角砾岩，其分布范围与金矿体吻合。热液隐爆机构的形成机制为：在硅岩与板岩的交界处形成的热液硅岩“盖”阻塞了热液系统，导致出现过压的地热环境，约49．5Ma时，由于东西向断裂复活，使脆性的硅岩发生破裂，最终导致了热液隐爆作用的发生。热液隐爆作用促使金元素从热液中沉淀，而热液隐爆机构则为金矿化提供了赋存空间。A new type of gold mineralizat ion -controlling structure - hydrothermal crypto- explosive crater was identified at the Larma gold-uranium deposit in the border regions between Gansu and Sichuan provinces, western China. The hydrothermal crypto-explosive crater is ellipse-shaped at the surface, while funnel-like in profile. A silicalcap composed of hydrothermal siliceous breccia is distributed at the top of the crater, while hydrothermal crypto-explosive breccias are in the cen tre. The configuration of the crater is roughly consistent with the distrbution of gold ore bodies. The formation mechanism of the crater is: first, a silica cap composed of hydrothermal siliceous metasomatic rock was formed at the contact area between the siliceous rock and the slate, and btriked the movement of hydrothermal nuid and resulted in the appearance of over-pressed geothermal environment. Then, at 49. 5Ma, the rejuvenation of the EW-striking faults in Larma area resulted in the breaking of the brittle silica cap, followed by the crypto-explosion of hydrothermal fluid. In Larma gold-uranium deposit, the hydrothermal coypto-explosion gave rise to the precipitation of gold from the hydrothermal fluid, while the crypto-explosive crater provided the space for gold mineralization.

关 键 词：金矿床 铀矿床 热液隐爆机构 热液成矿 

分 类 号：P619.140.5[天文地球—矿床学] P618.510.5[天文地球—地质学]