Kenex has been working on Namibian exploration projects since 2005, and has undertaken on-ground project management for local explorers as well as prospectivity modelling throughout the country. Our prospectivity modelling evaluated the potential for iron-oxide copper gold (IOCG) deposits in Namibia, up through Zambia and into Botswana. We used the GIS based fuzzy logic spatial modelling technique with publically available geological, geophysical and geochemical databases to generate new targets for IOCG exploration.
IOCG deposits include many diverse ore systems and are found on all continents. They are generally found in post-Archean rocks from the Early Proterozoic to the Pliocene and are located in zones of extensional tectonics along pre-existing rift zones. IOCG mineralisation environments are usually known to contain significant amounts of igneous activity, high heat flow, and source rocks that are relatively oxidised. The IOCG deposits of western Zambia, north western Botswana, and northern Namibia are found in rocks of the Lufilian Arc; a Mesoproterozoic to Neoproterozoic rift basin which closed during the Pan-African orogeny.
Our modelling was based on information from the weights of evidence modelling of the Eastern Fold Belt of the Mt Isa Inlier in Queensland, Australia, where the relationships between IOCG deposits and their source, transport pathways and traps are well known. This enabled us to reduce the subjective element of the fuzzy logic modelling technique and understanding of the mineral system model in Namibia where there are few known IOCG deposits.
From the modelling in Mt Isa and literature on IOCG systems in the Lufilian Arc we created predictive maps for the model which represented all stages of the mineral system model. These maps were combined using the fuzzy logic modelling technique and the result has mapped areas in Namibia, Zambia and Botswana with the same geological features as IOCG deposits in the Mt Isa region. These target regions therefore have increased potential to host IOCG mineralisation in Namibia. The fuzzy logic modelling reduced the exploration search area down by 90%, and has generated several targets for follow-up data collection and new modelling with detailed geological databases.
Anticlinal fold in the Northern region of Desert Minerals gold prospect.
Read Katie's paper about IOCG modelling in Africa presented at the SGA / SEG conference in Townsville in 2009.