煤系地层中高岭土矿床的主要成因类型及特征

沉积高岭土矿床,可分为煤层内高岭石夹矸和煤层间高岭土矿床二种类型。前者成分很纯、结晶很好。在煤系地层中,由于原始物质、地质构造、地形条件、水文地质等条件的具备,也发育风化矿床,它们多半为软质粘土或木节土。内蒙老石旦高岭土矿床是石炭系煤层及其夹矸的风化残余产物。甘肃安口高岭土矿床也是侏罗系煤层,夹矸及顶板泥质岩的风化残余产物。四川叙永高岭土矿床则为二迭系煤层及其底板风化淋滤的结果。由于煤层自燃,还存在高岭土经烧变而成的天然熟料,可以作为一种变质高岭土矿床。本文从具体矿床实例出发,提出了煤系地层中高岭土矿床存在的主要成因类型,在理论上,找矿和利用上,均具一定意义。

MAIN GENETIC TYPES AND CHARACTERISTICS OF KAOLIN DEPOSITS IN COAL MEASURES STRATUM

Sediment-Kaolin deposit may be divided into two types: Kaolinic band within the coal seam and kaolin deposit between two coal seams. The former is very pure in composition and fair in crystallization Because of material origin, geological structure, orographic condition, hydrogeological condition, etc. possessed in coal measures stratum, mineral deposit by weathering process is also developed. It is mostly soft clay or kibushi clay. Laoshidam kaolin deposit from Neimenggu is the residual product of carboniferous coal seams and its intercalated bands within the coal seam by weathering. Ankou kaolin deposit from Gansu is also the residual product of jurassic coal seams, clay rock of coal roof and intercalated bands within the coal seams by weathering. Xuyong kaolin deposit from Sichuan is formed as an infiltrated result of permian coal seams and coal seat by weathering. Owing to coal spontaneous combustion, there is still a natural grog of kaolinclay by sintering, which may be considered as a metamorphic kaolin deposit. According to the specific examples of mineral deposits, this paper has proposed the main genetic types of kaolin deposit in coal measures stratum. It has certain significance in the genetic theory, exploring and uses of koolin deposits.