Tectonic investigation of Masvingo Province, Zimbabwe: preliminary report

This report summarises the preliminary results of a structural investigation in the Masvingo (Victoria) Province of SE Zimbabwe undertaken as part of a hydrogeological study of the occurrence of groundwater in crystalline basement rocks. A review of the tectonic development of the region from available literature is presented together with the initial results of a remote sensing study using Landsat MSS imagery and aerial photographs, as well as reconnaissance fieldwork. The Zimbabwe craton has had a complex tectonic history involving several episodes of ductile to brittle deformation extending back well into the Archaean. From a groundwater viewpoint the brittle deformational events commencing in the Late Archaean at about the time of emplacement of the Younger Granites are considered to be of greatest importance. The fracture patterns noted from past geological mapping and evident on Landsat imagery provide clues to the tectonic history of the region but further field study will be needed to establish age relationships, which cannot be unequivocally decided from remote sensing data alone. Nevertheless, on the basis of available evidence, a possible model of the Late Archaean-Early Proterozoic tectonic development of the region is discussed. This report also considers the problems of using empirical tectonic models in the exploration for groundwater. A follow-up work programme is discussed.