当前位置: X-MOL 学术Minerals › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Mineralogy and Genesis of the Kihabe Zn-Pb-V Prospect, Aha Hills, Northwest Botswana
Minerals ( IF 2.2 ) Pub Date : 2020-07-31 , DOI: 10.3390/min10080685
Nicola Mondillo , Maria Boni , Giuseppina Balassone , Nigel Forrester , Francesco Putzolu , Licia Santoro

The Kihabe Zn-Pb-V > (Cu-Ag-Ge) prospect is located at the boundary between Namibia and Botswana (Aha Hills, Ngamiland District) in a strongly deformed Proterozoic fold belt, corresponding to the NE extension of the Namibian Damara Orogen. The Kihabe prospect contains Zn-Pb resources of 14.4 million tonnes at 2.84% zinc equivalent, Ag resources of 3.3 million ounces, and notable V-Ge amounts, still not evaluated at a resource level. The ores are represented by a mixed sulfide–nonsulfide mineralization. Sulfide minerals consist mainly of sphalerite, galena and pyrite in a metamorphic quartzwacke. Among the nonsulfide assemblage, two styles of mineralization occur in the investigated samples: A first one, characterized by hydrothermal willemite and baileychlore, and a second one consisting of supergene smithsonite, cerussite, hemimorphite, Pb-phosphates, arsenates and vanadates. Willemite is present in two generations, which postdate sulfide emplacement and may also form at their expenses. These characteristics are similar to those observed in the willemite occurrences of the nearby Otavi Mountainland, which formed through hydrothermal processes, during the final stages of the Damara Orogeny. The formation of the Kihabe willemite is likely coeval. Baileychlore is characterized by textures indicating direct precipitation from solutions and dissolution–crystallization mechanisms. Both processes are typical of hydrothermal systems, thus suggesting a hydrothermal genesis for the Kihabe Zn-chlorite as well. Baileychlore could represent an alteration halo possibly associated either with the sulfide or with willemite mineralization. The other nonsulfide minerals, smithsonite, cerussite, various Pb-phosphates and vanadates, are clearly genetically associated with late phases of supergene alteration, which overprinted both the sulfide and the willemite- and baileychlore-bearing mineralizations. Supergene alteration probably occurred in this part of Botswana from the Late Cretaceous to the Miocene.

中文翻译:

博茨瓦纳西北部Aha Hills的Kihabe Zn-Pb-V前景的矿物学和成因

Kihabe Zn-Pb-V>(Cu-Ag-Ge)前景位于纳米比亚和博茨瓦纳之间的边界(Ngamiland区,Aha Hills),处于强烈变形的元古代褶皱带中,与纳米比亚达马拉造山带的NE扩展相对应。Kihabe的前景包含1440万吨的Zn-Pb资源(锌当量为2.84%),Ag的资源为330万盎司以及显着的V-Ge量,但仍未在资源水平上进行评估。矿石以硫化物-非硫化物混合矿化为代表。硫化物矿物主要由变质石英砂中的闪锌矿,方铅矿和黄铁矿组成。在非硫化物组合中,所研究的样品中发生了两种矿化方式:第一种矿化的特征是水热的硅铝石和贝利特石,第二种矿化的超基因的是新铁匠石,陶粒,半变石,铅磷酸盐,砷酸盐和钒酸盐。硅藻土有两个世代存在,它们在硫化物沉积之后就存在,并且也可能由其产生。这些特征与在达玛拉造山运动的最后阶段通过热液作用形成的附近奥塔维山地的硅藻土事件中观察到的特征相似。Kihabe硅藻土的形成很可能是同时期的。Baileychlore的特征在于质地指示溶液中直接沉淀和溶解-结晶机制。这两个过程都是热液系统的典型特征,因此也暗示了Kihabe锌-亚氯酸盐的热液成因。Baileychlore可能代表可能与硫化物或白榴石矿化有关的蚀变晕。其他非硫化物矿物,新铁矿,陶粒,显然,各种Pb-磷酸盐和钒酸盐与超基因改变的后期在遗传上相关,超基因改变的后期覆盖了硫化物以及承托有白硅石和贝利普利的矿化作用。从晚白垩世到中新世,博茨瓦纳的这一部分可能发生了超基因改变。
更新日期:2020-07-31
down
wechat
bug