Geology, Geochemistry and Geochronology of the Kenticha Rare Metal Granite Pegmatite, Adola Belt, Southern Ethiopia: A Review

Abstract

This work reviews the geology, geochemistry and geochronology and discusses the spatial and temporal relationship of the granite pegmatite and the rare metal mineralization of the Kenticha granite pegmatite, southern Ethiopia using published and unpublished works to give a comprehensive understanding about the formation of the mineral deposit. The Kenticha rare metal pegmatite belt comprises several groups of pegmatites which show a high magmatic fractionation, regional and compositional zoning, mineralogical assemblage, and secondary alterations. The internal zonation shows high degree of evolution from the border to the core zone during crystallization and solidification of the leucogranitic to pegmatitic melt. Tantalum mineralization at Kenticha includes zoned tantalite-(Mn) and columbite-(Mn), as well as microlite, pyrochlore, uranmicrolite, and rare tapiolite, ixiolite/wodginite and Ta-bearing rutile. The tectonic setting of the Kenticha granite pegmatite in the Within Plate Granite (WPG) to syn-Collisional Granite (syn-COLG) suites and probably sourced from extreme fractionation of syn-to late tectonic granites or anatexis process of the metasedimentary rocks in the area. The emplacement of the Kenticha pegmatite was at ca. 530 Ma and temporally related to the post-collisional phase of granitic magmatism at 570 -520 Ma, after the last tectonic stage of east African orogeny during the late stage of Gondwana assembly.

Structural and tectonic evolution of suture‐related belts and post‐accretionary systems in the Arabian‐Nubian Shield

“…The Adola Belt has been divided into Lower, Middle, and Upper Complexes (Kazmin et al, 1978; Mohammedyasin, 2017). The Lower Complex is made up of high‐grade gneisses and migmatites from the Archaen cratonic basement, as well as quartz‐feldspathic gneisses and schists.…”

“…(Figure 10b). The Middle Complex consists of psammitic and pelitic metasediments with some marbles and schists from the Lower to Middle Proterozoic, whereas the Upper Complex is made up of low grade, mostly greenschist facies, volcanosedimentary ophiolitic assemblages from the Neoproterozoic (Mohammedyasin, 2017; Tadesse, 2004). The granite–gneiss terrane (Figure 10b) has been subdivided into the Burji‐Moyale and Adola‐Genale sub‐terranes.…”

“…The mafic and ultramafic metasedimentary rocks (fold and thrust belts) that make up the volcano‐sedimentary ophiolite suites are overprinted by Ediacaran deformation and reflect the Cryogenic arc–arc sutures (Abdelsalam & Stern, 1996). The volcano‐sedimentary unit consists of schists, amphibolite, metaconglomerate, quartzite and mafic to ultramafic bodies (Mohammedyasin, 2017).…”

Evaluation of mining and mineral processing methods’ impact on tantalite concentrate in Kenticha open pit mine, southern Ethiopia

“…The host granitic pegmatite, 2 km long and 400–700 m wide, has intruded N–S trending serpentinite and talc-chlorite schist. Kenticha granite pegmatite field comprised of quartz, spodumene pegmatite, muscovite pegmatite, blocky microcline and muscovite-albite granite, biotite granite, two-mica granite and alaskitic granite (Tadesse et al 2003; Mohammedyasin 2017). The mineralization is complex type and the commercial concentrations of Ta, Nb, Hf, Zr, REE, U and Th are related to Be, Li, Cs, Rb- bearing zones of the pegmatite (Tadesse 2001).…”