滇中砂岩铜矿伴生银的赋存状态及富集规律初探

Occurrence state and enrichment regularity of sandstone copper deposit associated silver in the central part of Yunnan Province

在滇中裂谷盆地内,中生代形成一套陆相红色含铜砂岩建造矿床,其中普遍伴生银。银呈两种状态存在:一是呈类质同象(或银的次显微晶粒)分布在铁铜硫化矿物中这是主要的;另一类呈银的独立矿物形式产出。伴生银品位一般大于10×10-6,最高44×10-6,推算铜银储量之比为400:l。高品位的富银矿段或单银矿体一般受三个条件控制,一是构造发育,特别是近东西向断裂破碎带,二是混合矿带与黄铜矿黄铁矿带,载体矿物多而种类复杂;三是石英脉等后生脉体发育。

In the rift basin of the middle of Yunnan Province, there is a set of the Mesozoic continental red copper sandstone deposit which generally associated silver. Silver shows in two kinds of state： one is isomorph（or silver submicroscopic crystal grain） distributed in the iron and copper sulfide mineral of which is the main; another in the form of independent silver minerals output. Associated silver grade is generally greater than 10× 10^-6, the highest 44 ×10^-6, calculates the ratio of copper and silver reserves of 400： l. High grade rich silver or single silver ore body generally controlled by the three conditions, one is structure development, especially nearly east-west fault fracture zone, the second is mixed ore belt with pyrite and chalcopyrite, types of carrier minerals and more complex;the third they are quartz vein and other epigenetic vein body development.