乌拉山金矿带成矿物质来源的初步研究

PRELIMINARY STUDY OF ORE-FORMING MATERIAL SOURCE OF GOLD ORE BELT IN WULA MOUNTAIN,INNER MONGOLIA

通过原岩的含金建造,岩石含金性讨论,微量元素、稀土元素、包裹体特征及硫、氢、氧、碳、铅同位素的研究,对乌拉山金矿带成矿物质来源作了探讨。认为上有太古界乌拉山群是金矿形成初始矿源层,铅、硫等成矿物质主要来自地壳及下层富含金的某些强烈活动带,而成矿流体主要为渗流加热大气降水,部分来自变质—岩浆水的混合水。原岩属幔源分熔的基性—中基性火山沉积建造,幔源物质经后期大陆增生,沉积壳叠加改造,由幔源变成壳源物质,后期地质事件产生能源,使矿源层中的成矿物质活化,转移,富集成矿。

On the basis of the study of gold bearing formation of primary rock and gold bearing property of the rocks,the source of ore forming material of gold ore belt in Wula mountain is discussed through the analyses of the characteristics of trace elements,REE elements,fluid inclusions in minerals and of the isotopes of sulphur, hydrogen, oxygen, carbon and lead. It is suggested that the upper Arceozoic Wula Mountain Group is the primary source bed of the gold. The ore forming material such as lead,sulphur etc. is derived form the earth crust and from some of the intensive active deep-seated zone rich in gold,and the ore forming fluid is predominantly vadose meteoric hot water partly derived from the mixture of metamorhpic and magmatic water. The o-riginal rock is basic and intermediate basic volcanic sedimentary formation derived from the mantle. The mantle derived would be changed into a crustal one through continental accretion and superimposed reformation of sedimentary crust in later stage. The geological events in later stage produced energy which made the ore forming material in source bed being activated,transported and then enriched to from ore deposit.