摘要
渔塘坝硒矿床是目前我国发现含硒量 (85 90× 10 -6)最高的小型独立硒矿床 ,其赋矿岩石主要为硅质岩 ,且发育程度较高。早二叠世晚期的黑色碳质硅质岩系 ,是区内的赋矿层位 ,它局限于特定的沉积相位 ,即碳酸盐台地海盆浅部沼泽 (藻沼 )环境沉积的黑色碳质硅质岩相带 ,硒矿化层和这套碳质硅质岩相带密切相关 ,其矿化相带呈NW向展布。硅质岩的SiO2 含量变化较大 (6 4 .2 %～ 94 .85 % ) ,平均为 75 .9% ;Fe2 O3 、FeO、MnO、TiO2 、Al2 O3 和MgO等含量相对较高 ,与其它热水成因硅质岩相近 ;硅质岩富含As、Sb、Fe和Ag ,而贫Cu、Co和Ni;在Al Fe (Cu +Co +Ni)三角图、U—Th相关图和P2 O5 Y相关图上的投影特征 ,也同样显示出硅质岩的热水成因特征。另本区硅质岩中的Cr含量较大 ,且 (Fe +Mn) /Ti的比值为 6 .34。
The selenium diggings in Yutangba is the small independent deposit, which has the highest contents of selenium (8 590×10 -6 ). The selenium hosted rock is siliceous rocks, and its development degree is very high. The location of selenium hosted stratum is carbolic and siliceous rock series, which is in the early time of Permian Period. It is limited in a given sedimentary facies, named as carbon bearing siliceous rock facies belt, which is closely related with NW selenium mineralizing layer, was deposited in swamp environment of neritic basin of carbonate platform. The SiO 2 contents of siliceous rocks are from 64.2%～94.85%, the average value of which ( 75.9% ) and the relatively high Fe 2O 3, FeO, MnO,TiO 2, Al 2O 3 and MgO values are similar to hydrothermal cherts. The enrichment of As, Sb, Fe and Ag,while depletion of Cu, Co and Ni in the siliceous rocks,along with the projection of the cherts in Al Fe (Cu+Co+Ni) ternary diagram, in U Th relative diagram and P 2O 5 Y relative diagram,all show the characteristics of hydrothermal cherts. Moreover, due to the characteristics of Cr enriched and the ratios of (Fe+Mn)/Ti, the genesis of the siliceous rocks in this selenium diggings may be related with Permian volcanism when erupting basalts in E'mei mountain.
出处
《沉积学报》
CAS
CSCD
北大核心
2002年第4期727-732,共6页
Acta Sedimentologica Sinica
基金
中国科学院 1 997年度"百人计划"
国家自然科学基金项目 (批准号 :497731 97)资助
