石门三板桥石膏矿床特征及成矿控制因素

三板桥石膏矿床赋存于早第三纪古新世晚期沙市组上段，为一内陆湖相沉积矿床。矿体呈层状，似层状，有７个采矿层，平均厚６２ｍ，平均品位７３％，矿石类型为石膏及硬石膏，石膏主要分布在上下两个水化带上，中间为硬石膏原生带，矿床成生在红色断陷盆地次凹湖湾处，并处于与外部盆地联接的通道口上，盆地差异性沉降，预备盆地的卤水补给，是形成厚大矿体的主要原因。

SHANBANQIAO GYPSUM DEPOSIT CHARACTERISTICS AND METALLOGENIC FACTOR-CONTROLLED IN SHIMENG

Shanbanqiao gypsum deposit occurs on the upper section of Shashi formation,late Palcoccne,carly Tcrtiary,it is an intracontinentallake facies sedimentary deposit.There are the 7 minabal orebeds,their average thickness is 67 m,their average grade is 73 %.Gypsum and anhydric Are its two kinds of the ore styles. The gypsum mainly distributes in the two hydration beds of upper and lower,the middle layer is anhyditc primary zone.The deposit formed at the subdepression lake surrounding of the red downfault basin and the tunnelmouth which connected with the external basin.The differential subsidence of the basin,prcparing basin of bittern supply is main factors which formcd the thickness and large gypsum deposit.