伟晶状红柱石矿床的地质特征及成因探讨——以杨乃沟红柱石矿床为例

伟晶状红柱石矿床,产于中元古界小寨沟组下段,含石榴石、十字石炭质黑云母片岩和炭质黑云母石英片岩中.矿体呈层状、透镜状,共有六层,具有一定层位.矿体中红柱石晶体粗大,有的长达30cm,横断面直径达5-7cm,各晶体均沿片理面定向排列.矿区内未见花岗岩体出露,矿区外围虽有花岗岩体分布,但距离矿体很远,矿体并不受岩体接触带控制.根据矿体形状、产状特征,红柱石矿床是在区域变质过程中,由于变质热液的参加,使铝土质岩层发生重组合和重结晶作用而形成了伟晶状红柱石矿床.

A DISCUSSION ON THE GEOLOGICAL CHARACTERISTICS AND GENESES OF PEGMATITIC ANDALUSITE DEPOSITE

The andalusite deposite at Yang Naigou was formed in lower section of Xiao Zaigou formation,mesoproterozoic erathem,composing of garnet, staurolite-carbonace-ous-biotite-schist, and carbonaceous-biotite-quartz-schist.The andalusite bodies are stratified and lentoid, and have six strata. Some of the bodies have ramifications along the strike with certain hiorzons.Andalusite crystals are macrocrystallines. Some are 30 cm in lengh, 5-7cm in diameter. Each crystal is directive spreading along the schislosity-section. There are no outcrops of granite in mining area. Granite is distributed in the periphery of mining area far from the andalusite bodies, and its contact zone can't control the pegmatitic andalusite bodies.Based on the form of pegmatitic andalusite bodies and the characteristics of the-ir occurrence, the pegmatitic andalusite deposite was formed during the process of the zone metamorphism due to the recombination and recrystallization of alumo rock formation caused by the join of metamorphic hydrothemal.