云南永胜宝坪滑覆构造聚矿

Ore Accumulation Role of Anti-thrust Gliding Nappe in Baoping Copper Deposit, Yongsheng County, Yunnan Province

文章通过对云南永胜宝坪矿床构造地质填图、同构造石英脉及含铜石英脉型矿石的热活化法ESR定年研究 ,结合区域地层接触关系、构造及其年代学等结果 ,发现宝坪矿床受控于程海逆冲断裂上盘发育的滑覆构造 ,主要成矿作用的发生及滑覆构造的形成与整个盐源_丽江构造带于喜马拉雅早中期陆内褶皱造山同时发生 ,工业矿体的形成主要与同构造地下含铜热水活动有关。经勘查证实 ,矿化严格受滑覆构造控制 ,并具明显分带性 :与深部构造岩浆带联通的后部张性断裂带构成导矿构造 ,伴脉状矿化 ;平卧叠褶的软、硬岩层互层系组成的中部和前部带 ,因缓倾顺层剥离剪切糜棱岩发育 ,构成多级次屏蔽_容矿构造 ,赋存层状。

The Baoping deposit in Yongsheng County is controlled by the anti-thrust gliding nappe growing on the upper side of the Jinhe-Chenghai fault. The main ore-forming process, the formation of the anti-thrust gilding nappe and the fold-orogenic process of the Yanyuan-Lijiang tectonic zone took place in the same period, i.e., in the period from early Himalayan to middle Himalayan. The deposit is therefore a syntectonic-geothermal-fluid subsequent deposit. Exploration has demonstrated that the mineralization is controlled by the anti-thrust gliding nappe and has obvious zonality. The rear tensional faulted zone connected with the deep tectonic-magmatic belt acted as the passageway for ore fluids, in which veinlike mineralization can be seen. Stratiform and stratoid orebodies are hosted mainly in the middle and front zones, where flat-lying shingle-folded weak strata and rigid strata are interbedded with each other, and many gently-dipping bedding shear-mylonitic zones serve as multilayered shielding strata.