GEOLOGY, GEOCHRONOLOGY AND REGIONAL CORRELATION OF THE GHANZI RIDGE, BOTSWANA

The Neoproterozoic Ghanzi Ridge is a 250 km-long section of the Ghanzi -Chobe Belt in Botswana, which represents the northeastern extension o f the intracratonic branch of the Damara Orogen. The oldest unit is th e Kgwebe Formation, which is composed of metarhyolites, metabasalts, a nd siliciclastic metasediments. One metarhyolite has a U-Pb zircon age of 1106 +/- 2 Ma and can be correlated with the Nuckopf Porphyry and Oorlogsende Porphyry in Namibia. The overlying Ghanzi Group is compose d of siliciclastic metasediments and subordinate calcareous metasedime nts. The upper part of the Ghanzi Group can be correlated with the Kam tsas Formation in Namibia. The age constraints for the Ghanzi Ridge Pr ecambrian rocks are set by a older limit of approximately 1100 Ma and a younger limit of 600-750 Ma.