Pyrochlore from the Bailundo Carbonatite Complex (Angola): Compositional variation and implications to mineral exploration

Costa, I.; Roseiro, José; Figueiras, Jorge; Rodrigues, Pedro; Mateus, António

doi:10.1016/j.jafrearsci.2021.104154

Cited by 5 publications

(1 citation statement)

References 27 publications

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“…Timofeev et al (2015) investigated the solubility of Nb in fluoride-bearing aqueous solutions at temperatures of 150-250°C, finding that solubility increased markedly at higher HF concentrations, and that precipitation of Nb solids and fluorite could occur if pH increased as a result of an acidic country rock fluid reacting with carbonate rocks. The presence of F-rich minerals such as fluorcarbonates and F-rich pyrochlores (as found at both Chilwa Island and Kangankunde) at the Bailundo Carbonatite Complex in Angola was taken to indicate fenitising fluids enriched in F -, with high HF activity (Roseiro, 2017;Roseiro et al, 2019). Chebotarev et al (2017) also invoked F and low pH to explain the evolution of Nb mineralisation in the Chuktukon carbonatite massif in Russia, commenting that during hydrothermal alteration, fluids were able to dissolve fluorapatite in carbonatite.…”

Section: Niobium Mobilitymentioning

confidence: 99%

A comparison of the fenites at the Chilwa Island and Kangankunde carbonatite complexes, Malawi

Dowman

Wall²,

Treloar³

2022

MinMag

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Carbonatites are igneous carbonate rocks. They are the main source of the rare earth elements (REE) that are essential in low carbon and high technology applications.Exploration targeting and mine planning would both benefit from a better understanding of the processes that create the almost ubiquitous alkaline and rare earth (RE)-bearing metasomatic aureoles in the surrounding country rocks.Using SEM-based analysis and whole rock geochemistry, we investigated the composition and mineralogy of the fenite aureoles developed around the RE-poor Chilwa Island carbonatite and the RE-rich Kangankunde carbonatite, which intrude similar country rocks in the Chilwa Alkaline Province of Southern Malawi. Although common characteristics and trends in their mineralogy and composition may be typical of fenites in general, there are significant differences in their petrography and petrogenesis. For instance, the mineralogically diverse breccia at Kangankunde contrasts with the intensely altered

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Section: Niobium Mobilitymentioning

confidence: 99%