Lithology and Mineral Resources ( IF 0.8 ) Pub Date : 2020-10-28 , DOI: 10.1134/s0024490220060085 Ola Peter Sunday , Bamisaiye Oluseyi Adunola , Idowu Thaddeus
Abstract
Several barite deposits have been reported to occur in Nigeria within the Benue Trough, one of the West Central African Rift Systems (WCARS) considered variously as an aulacogen, strike-slip or pull-apart basin. In spite of these occurrences and the high local and international demand for barites, Nigerian barite is yet to find a place even in its local market probably due to the poor knowledge of the fundamental properties of the barites. To throw more light on this some deposits that are mined on artisanal basis in the Trough were studied alongside an overview of the evolution of the basin and the geochemistry and petrogenesis of the barite. Barites in the area of study occur as white, reddish-brown and clear varieties with specific gravity varying between 3.3966 and 4.3432 based on pycnometric and immersion methods. They occur as epigenetic veins of between about 0.1 m to more than 1.5 m, which encourages open cast mining. Chemical analysis show that the samples studied contain between 72.61 and 72.12% Ba corresponding to a calculated total BaO of 48.37 and 60.1%. The other relatively significant elements but of less value in the samples include Si, Fe, Sr, Ca, Al, Pb, Mg, Mn, P, and Ni. XRD results also show barite mineralogical association with wenkite and plumbian barite of insignificant quantity. The barites likely formed from intermingling of infiltrating solutions containing barium with soluble sulphates arising within the rocks passing through fractures created during the Late Cretaceous inversion in the basin. The inversion is suggested herein to have resulted from magmatic underplating and consequent peneplanation in the middle Benue Trough.
中文翻译:
尼日利亚贝努海槽某些部分的静脉型重晶石的地球化学,矿物学和岩石成因
摘要
据报道,尼日利亚的贝努尔海槽内有数个重晶石矿床,贝努尔海槽是西非中部裂谷系统(WCARS)之一,被广泛认为是成因作用盆地,走滑盆地或拉脱盆地。尽管发生了这些事件,并且当地和国际上对重晶石的需求很高,但尼日利亚重晶石甚至尚未在其本地市场上找到位置,这可能是由于对重晶石的基本特性了解不足。为了进一步阐明这一点,对海槽中手工开采的一些沉积物进行了研究,同时概述了盆地的演化以及重晶石的地球化学和成岩作用。根据比重瓶法和浸没法,研究区域的重晶石为白色,红棕色和透明变种,比重在3.3966和4.3432之间变化。它们以约0.1 m至超过1.5 m的表生岩脉出现,这鼓励了露天开采。化学分析表明,所研究的样品含有72.61至72.12%的Ba,相当于计算出的总BaO为48.37至60.1%。样品中其他相对重要但价值较小的元素包括Si,Fe,Sr,Ca,Al,Pb,Mg,Mn,P和Ni。XRD结果还表明,重晶石矿物学与少量的文克石和铅质重晶石有关。重晶石可能是由含钡的渗透溶液与溶解在硫酸盐中的可溶性硫酸盐混合而成的,这些岩石通过穿过盆地晚白垩世反转形成的裂缝而出现在岩石中。在此建议该倒转是由于贝努厄中层中的岩浆底板作用和随后的穿透作用引起的。