Abstract

Structurally controlled Late Archaean gold mineralizations associated with felsic plutons in the Harare–Shamva greenstone belt, Zimbabwe, are synchronous with the emplacement of their hosts. The ages of these mineralizations are identical to those reported from other mesothermal gold deposits elsewhere in the Zimbabwe Craton. The Pb and Nd isotopic signatures of the host plutons are compatible with a direct mantle or a short crustal residence period for the protoliths to the host intrusions. The coincidence of the Pb-isotope data from ore minerals with the whole-rock trends (errorchrons) of their host intrusives strongly suggests that the gold could have a magmatic, rather than a metamorphic, source. There is no evidence from the Pb isotopes of significant involvement of older basement in the genesis of gold deposits associated with felsic intrusions in the Harare–Shamva greenstone belt. On a craton-wide scale, the time frame around 2.65 Ga represents a period of significant crustal growth (through addition of mantle-derived magma), deformation, and metamorphism. The temporal and spatial coincidence of these three parameters has created favorable conditions for the emplacement of the largest class of Archaean gold mineralizations that are currently known in the country.

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