湘西北岩头寨钒矿成矿地质特征及成因

Metallogenic characteristis and genesis of the Yantouzhai vanadinum deposit in the northwesten Hunan

岩头寨钒矿赋存于寒武系底部牛蹄塘组黑色岩系中,含钒岩系以富含有机质的碳、磷、硅质岩石组合为特征。矿体呈层状,具多层性,平均厚度2.7~7.1 m,V2O5平均品位0.80%~0.84%。矿石类型主要为硅质岩夹硅质炭质页岩或互层和硅质炭质页岩型2类;含钒矿物主要为含钒伊利石。探明的资源储量达311万t。文章通过对区域地质背景、矿区地质特征、矿体特征、矿石矿物特征等分析,认为矿床受地层、岩性、岩相、古地理和古构造条件控制;钒在沉积和成岩过程中都离不开生物地球化学作用。成矿作用是在有机质参与下发生的元素迁移、富集作用,经成岩期富化而形成矿床。钒的生成与菌藻类的活动密切相关,因此,矿床属于化学生物地球化学沉积矿床。

The Yantouzhai vanadium deposit occurs in the black rock series of Niutitang formation at the bottom of Cambrian strata,the ore- hosted stata are characterized with rich organic lithological association consisting of phosphous- bearing,carbon-bearing and silicate rocks. The orebodies display as stratified and multi layers,the average thickness of the orebody is from 2. 7 m to7. 1 m,and the average vanadium grade of 0. 8% ~ 0. 84%. The main ore types are silicalite type intercalated with siliceous carbonaceous shale or interbeds and siliceous carbonaceous shale type. The main ore mineralis vanadium- bearing illite. The proven vanadium resource reaches 3. 11 million tons. Based on integrated analysis of the regional geological background,geological features of the deposit area,characteristics of orebodies and ore minerals,it is thought that the formation of deposit is controlled by the strata,lithogy,lithofacies,paleo- geography and paleo structure,the biogeochemical process is the main mechanism during the deposition and diagesis of the vanadium- bearing matter. Under the participation of organic matter,the vanadium mineralization was formed by the migration,and enrichment of vanadium after diagenism. The vanadium deposition is closely associated with the alage activity,the genesis of deposit belongs to the chemicalbiogeochemical sedimentary type.