中条山铜矿区电气石特征及其对成岩成矿作用的示踪意义

Tourmaline from the Zhongtiaoshan Copper Metallogenic Area: Its Characteristics and Indication Significance for Ore-forming Process of That Area

中条山地区是我国著名的铜矿床集中区。在胡-篦型层控铜矿床容矿热液沉积岩建造和铜矿峪型铜矿床容矿钙碱性次火山-火山沉积岩系及其它地质环境内发现有大量电气石产出。电气石均属镁-铁系列,且以不含锂为主要特征。电气石由海底盆地热液沉积作用、火山热液喷气作用及热液交代作用形成。这些地质作用的产生均与中条山地区21亿年左右的岩浆活动有关。由于形成条件和形成方式不同,在不同地质环境产出的电气石具有明显不同的光性和标型特征。

The Zhongtiaoshan area is one of the famous concentration areas of copper deposits in China. A large quantity of tourmaline has been found in the hydrothermal-sedi-mentary formation which hosts Hu-Bi type stratabound copper deposits, the caicalkaline subvolcanic-volcanic sedimentary rocks which host the Tongkuangyu type copper deposits, and other geological environments of this area. The content of tourmaline can be more than 50％ in tourmalinite, but varies in the range of 5—40％ in other rocks. Due to the difference of formiug conditions and. maimers in different geological environments, tourmalines show obviously different optical properties and typomorphic characteristics. All tourmalines are dravite-schorl series and contain virtually no lithium. They were formed as a result of hydxothermal deposition in submarine basin, through volcanic hydrothermal exhalation and hydxothermal metasomatism which, however, were all relatedto magmatic activities in the Zhongtiaoshan area in 2100 Ma age or so.