Assessing the geological relationships between the mafic-ultramafic intrusion in the Haib area and the Vuurdood Subsuite, Richtersveld Subprovince

Abstract

Abstract The Haib porphyry copper deposit is situated in the Richtersveld Subprovince and is host to unique Palaeoproterozoic porphyry copper mineralisation in Namibia. Several lines of evidence, including machine-learning geothermobarometry, indicate that the deposit is exposed at mid- to upper-crustal levels, as constrained from average pressure and temperature estimates of 4 kbar and 870°C, respectively. The Haib porphyry copper deposit is associated with, and is in close proximity to, a mafic-ultramafic intrusion named the Kokerboom Intrusion (KI) in this study. Together with several other mafic intrusions in this region, these intrusions are known collectively as the Vuurdood Subsuite of the Richtersveld Subprovince. The purpose of this study is to demonstrate a genetic link between the KI and the Vuurdood Subsuite using lithological characteristics, mineral and alteration assemblages, major and trace element geochemistry and U-Pb geochronology. Pyroxenites from the KI contain magmatic sulphides and have a geochemical affinity with shallow plutonic and volcanic rocks of the Haib porphyry, providing a unique mid-crustal perspective on porphyry copper deposit metallogenesis.