新疆乌伦古坳陷乌伦古河组碳酸盐化及铁锰矿化与铀成矿关系

Relationship Between Carbonation,Ferro-manganese and Uranium Mineralization in Ulungur Formation,Wulungu Depression,Xinjiang

在乌伦古坳陷开展铀矿地质调研时,发现出露于始-渐新统乌伦古河组上段的碳酸盐化、铁锰矿化及褐红色泥岩裂隙状褪色现象有规律地分布于断裂破碎带的上盘;顶山砂岩型铀矿点赋存于始-渐新统乌伦古河组下段砂岩中,也发育于断裂破碎带的上盘;这些矿化及褪色现象所代表的地质意义、形成机理及其与铀成矿的关系等就引起了关注。经过大量野外地质路线调查,仔细观测这些现象的分布规律、产出层位、状态及结构构造,查阅相关文献资料,得出碳酸盐化、铁锰矿化及泥岩褪色现象是沿断裂破碎带上升的深部含多金属地下卤水和浅部地下水混合(化合)卸载的产物;通过顶山铀矿化点分布位置、赋存层位、矿体形态、矿化及蚀变特征等因素分析,认为铀矿化与沿断裂破碎带上升的深部高压含还原剂地下水关系比较密切;碳酸盐化、铁锰矿化及泥岩褪色现象和铀矿化的空间产出位置,都显示出与断裂破碎带及其上升的深部地下水(卤水)有关。因此得出碳酸盐化、铁锰矿化及褪色现象对铀矿找矿具有指示意义,即:断裂破碎带附近如果存在这些现象,就有可能存在着铀矿化。

In Ulungur Depression,the carbonation,ferro-manganese mineralization and fissure fading in the maroon mudstone of the upper member of Ulungur River Formation were found regularly exposed in the hanging side of the fracture zone;Dingshan sandstone uranium occurrence in the lower member of Ulungur River Formation also occured in the handing side of the fracture zone.After a large number of field geological transverse surveys with detailed observation on the spatial distribution,occurring layer and altitude of the alteration and mineralization,fabrication and structure of rocks and study of related literature,it was concluded that carbonation,ferromanganese mineralization and fissure fading were the unloading products of mixing compound(chemical combination)of polymetallic brine rising from the deep underground and superficial groundwater along the fracture zone.By analyzing the location,morphology,mineralization and alteration characteristics of Dingshan uranium occurrence,the mineralization was believed closely related to deep high-pressure groundwater with reductants rising along the fracture zone.Therefore,the carbonation,ferro-manganese mineralization and mudstone fading can be used as indicators for uranium prospecting.