呷村—有热矿区含矿层位、含矿带精细结构对比及其找矿意义

发布时间：2018-05-21 09:28

本文选题：VMS型矿床 + 含矿层位　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：四川省白玉县呷村银多金属矿床是我国著名的VMS矿床之一,具有容矿火山岩系+硫化物矿体+喷气岩的“三位一体”特征,以及下部筒状或漏斗状网脉状矿(西矿带)和上部层状块状矿(东矿带)的“双层结构”样式。有热矿区位于呷村矿床的南部,目前人们对于其是否与呷村矿床属于同一含矿层、有热矿区是否存在类似呷村东矿带的以“黑矿”-重晶石组合为代表的隐伏银铜铅锌块状矿体有很大争议。本文以该矿床为研究对象,在详细野外资料基础上,结合室内的镜下观察、图件绘制等工作,对该呷村-有热矿区的含矿层位、含矿带精细结构有系统的认识。(1)详细的地层对比研究表明:有热矿区与呷村矿床含矿层位具有连续稳定的顶底标志层,以及下部中酸性、上部酸性的纵向岩性变化特征,表现为含矿层位底界出现流纹英安质角砾-集块岩,下部以一套流纹英安质熔岩-火山碎屑岩为主,上部为一套流纹质熔岩-火山碎屑岩,顶界均出现钙质碳质板岩及上覆的安山岩,据此认为呷村-有热地区位于同一含矿层位中,有热矿区是呷村矿床的自然南延部分。(2)呷村矿床和有热矿区含矿带精细结构对比表明:有热矿区北部19-31线由块状硅化流纹质火山岩+条纹条带状流纹质凝灰岩+千枚状绢云母凝灰岩组成火山喷发单元,以强烈的硅化为特征,发育大量的脉状-网脉状构造,与呷村西矿带完全可以对比;而有热南部39-55线则由块状“黄矿”矿石与流纹质火山碎屑岩组成喷气一火山单元,但缺乏重晶石、硅质岩等喷气沉积岩;以“黄矿”为主,仅形成铅锌贫矿体,与呷村矿床东矿带富含重晶石、以“黑矿”为主,形成银铜铅锌富矿体的特征有较大区别。同时,有热块状矿体上部还存在厚达70-130m的流纹质火山岩和脉状-网脉状矿体,据此认为有热矿带总体上可与呷村西矿带对比,代表热液喷流成矿系统的热水补给通道相,其中的块状(黄矿)矿体具微“双层”结构特征,有可能为早期热流成矿系统的另一个独立的“微”VMS矿床。(3)有热矿区已知矿体的东部可能存在类似呷村东矿带的以“黑矿”-重晶石组合为代表的隐伏银铜铅锌块状矿体,寻找此类矿体是有热矿区今后取得找矿重大突破的关键所在。
[Abstract]:The Gacun silver-polymetallic deposit in Baiyu County, Sichuan Province, is one of the famous VMS deposits in China, which has the characteristics of "trinity" of sulphide exhalations of volcanic rock series. And the "double structure" pattern of the lower tubular or funnel-shaped reticulated vein ore (west ore belt) and the upper layered massive ore (east ore belt). The Youre mine is located in the southern part of the Gacun deposit. At present, people are concerned about whether it belongs to the same ore-bearing bed as the Gacun deposit. It is controversial whether there is a concealed silver-copper-lead-zinc block orebody similar to the Gacundong ore belt, represented by the "black ore" barite association. On the basis of detailed field data, combined with indoor observation and drawing work, the ore-bearing horizon of the Gacune-Youre mining area is studied in this paper. Detailed stratigraphic correlation study of fine structure of ore-bearing belt shows that the ore-bearing strata of Youre mine and Gacun deposit have continuous and stable top-to-bottom marker layers, as well as the longitudinal lithologic characteristics of intermediate acidity and upper acidity in the lower part of the ore-bearing zone. In the bottom boundary of ore-bearing strata, there are fluid-grain amphitic breccide-aggregates, a set of fluid-amphitic lava and pyroclastic rocks in the lower part, and a set of fluid-pyroclastic rocks in the upper part of the ore-bearing bed. Calcareous carbonaceous slate and overlying andesite appear in the top boundary, so it is considered that the Gacune-Youre area is located in the same ore-bearing bed. The fine structure comparison between the Gacun ore deposit and the ore-bearing belt of the ore-bearing area shows that the northern 19-31 line of the ore-bearing area is striped and striped by massive silicified streamline volcanic rocks. A thousand sericite tuff forms a volcanic eruption unit, Characterized by strong silicon, a large number of vein-net vein structures are developed, which can be completely contrasted with the Gacunxi ore belt, while the 39-55 line in the southern part of Youre is composed of massive "yellow ore" ores and fluid-grained pyroclastic rocks, which constitute the air-jet volcanic unit. However, it is lack of exhalative sedimentary rocks such as barite, siliceous rock and so on, mainly "yellow ore", only lead-zinc lean ore body is formed, which is different from "black ore" and rich barite in east ore belt of Gacun deposit, and the characteristics of silver copper-lead-zinc rich ore body are quite different from those in east ore belt of Gacun deposit. At the same time, there are also fluid-grain volcanic rocks and vein-net orebodies in the upper part of the hot block orebody. It is considered that the thermal ore belt can be compared with the Gacunxi ore belt on the whole and represents the hot water supply channel facies of hydrothermal exhalation ore-forming system. The massive (yellow ore) orebody is characterized by a micro-" double layer "structure. It is possible that another independent "micro" VMS deposit. 3) in the eastern part of the known orebody of the thermal ore area, there may be a concealed silver, lead-zinc block orebody, represented by the "black ore" barite association, similar to the Gacundong ore belt, which may be another independent "micro" VMS deposit. Finding such orebodies is the key to make a great breakthrough in prospecting in hot mining areas in the future.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.2

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