寻找紧缺的银矿资源——地质工作者的急迫使命

由于近二十年来全世界工业的快速发展 ,银的用途益发广泛 ,白银需求量迅猛增加 ,它不仅是我国紧缺的矿产资源 ,而且已成为世界市场上的走俏商品 ,全世界已连续九年需大于供 ,九年累计缺银 1 0亿盎司 ,并且缺口越来越大。专家们预测 :到 1 998年底全世界库存的银锭消耗殆尽。我国前几年有 1 / 2 -1 / 3的白银靠进口 ,1 997年还进口白银 1 55吨。因而 ,银价剧烈上扬 ,从 1 996年的 4美元 /盎司 ,涨到 1 998年 2月份的 7.81美元 /盎司。与白银相反 ,近两年黄金供远过于求 ,1 997年全世界多出 3 93吨 ,故金价急剧下跌 ,从 1 996年的 3 87.87美元 /盎司 ,降到 1 998年 6月份的 2 87.9美元/盎司。由于银需求量增大 ,加之有色金属工业的不景气 ,银产量不仅不能增长 ,而且反而下降。因而人们提出寻找能根据需要而生产的、具有独立开采价值的银矿床 ,即独立银矿床。全世界有三大巨型成矿带 ,我国有四大银成矿区。这些成矿区带的核心是火山 -岩浆活动带。银成矿区带都受巨型或区域深大断裂带控制 ,独立银矿床多产于区域深大断裂带旁侧的次级断层交汇处或附近。独立银矿床的直接围岩可以是火成岩、沉积岩和变质岩 ,但是它们位于火山岩浆活动带中 ,而且以火山岩为主。

URGENTLY NEEDED SILVER MINERAL RESOURCE AND THE IMPATIENT MISSION OF GEOLOGISTS

The expansion of Ag utilization and increasing industrial demand for silver is ascribed to the rapid development of industry throughout the world in the past 20 years. Silver is not only an urgently needed product in the world market, but also an urgently needed mineral resource. In recent 9 years silver demand greatly exceeds its supply in the world. Some specialists forecast that stock silver in the world would be exhausted by the end of 1998. In the past several years China had to import silver from abroad, which accounts for 1/2-1/3 of the total need, to satisfy its demands for silver. The price of silver has risen suddenly, from one ounce for 4 dollars in 1996 to one ounce for 7.81 dollars in Feb. 1998. On the contrary, the supply of Au exceeds its demand in recent years and the price of Au rapidly drops down, from one ounce for 387.87 dollars to one ounce for 287.9 dollars in July 1998. Because of the increasing demand for silver and the non\|ferrous metal industrial depression, the output of Ag could not increase but to decrease. Under such circumstances some scholars have put forward the conception of independent silver deposits. So far there have been recognized three grand silver mineralization belts in the world and four metallogenic provinces in China. The core of these metallogenic belts is the volcano\|magmatic activity fault system. The metallogenic provinces are controlled by grand or regional deep giant faults and independent Ag deposits largely occur near or at the junctures of secondary faults on both sides of the regional deep giant faults. The direct country rocks of independent silver deposits could be igneous, sedimentary and metamorphic rocks that are located in volcano\|magmatic activity belts, with igneous rocks as the dominant host rocks.