塔里木盆地巴楚隆起奥陶系岩溶缝洞化学充填物成因分析

考察塔北巴楚岩溶露头,描述并列出巴楚露头区溶洞化学充填的充填物类型,通过常量、同位素和包裹体等地化分析测试手段的分析,探讨充填物的形成环境。结果表明:巴楚五道班和硫磺沟溶洞化学充填类型多且具有很好的代表性和对比性;五道班主要为钙华、方解石、萤石,硫磺沟主要为垮塌的钙华角砾岩、钙华、包壳砾岩、硫磺和石膏;硫磺沟古溶洞受热液影响明显,硫同位素测试结果显示硫磺和石膏不是蒸发沉积形成,而是热液成岩的产物,硫磺沟钙华表面多附着硫磺,说明钙华形成环境与深部热水有密切关系;五道班古溶洞为地下河沉积充填和热液化学充填的混合,方解石和萤石受热液影响,五道班钙华常与陆源碎屑物质伴生主要是富含碳酸氢钙的岩溶水过饱和析出沉淀而成;受热液影响充填的溶洞,化学充填物可形成大型矿床。
Through field investigation, the chemical filling of paleocave was described and listed in Bachu outcrop. And the major elements, isotope and fluid inclusion were used to discuss the environment of filling. The results show that the chemical fillings are representative and comparative in Wudaoban and Liuhuanggou areas. The chemical fillings of paleocave in Wudaoban are tufa, calcite, and fluorite. Instead, the chemical fillings of paleocave are collapsed tufa breccia, tufa, coated rocks, sulfur and plaster in Liuhuanggou. The influence of hydrothermon paleocave in Liuhuanggou area is significant. The tests of sulfur isotope show that the sulfur and plaster are the hydrothermal yield instead of the evaporativeyield. The surface of the tufa in Liuhuanggou is mostly covered with sulfur, which indicates that the formation environment of the tufa is bound up with deep hydrotherm. However, it is mixed by the fillings of underground river sediment and chemical fillings of hydrotherm in Wudaoban. The tufa in Wudaoban is often associated with terrigenous detrital materials, which is mainly due to the over-saturation precipitation of karst water rich in calcium bicarbonate. The chemical filling in karst cave that influenced by hydrotherm may form a large deposit