Fluid evolution in the Pote Shear Zone Harare-Shamva-Bindura greenstone belt (northeast Zimbabwe)

A fluid inclusion study was completed on syn-deformational quartz veins of the Pote River Shear Zone, which is situated on the border between the Hara re-Bindura greenstone belt and the granitoids of the Chinamora Batholith. T he fluid inclusions were studied by means of microthermometry and Laser-Ram an microspectrometry. The fluid inclusions consist of three major compositi onal types: (1) H2O-CO2 +/- N-2 +/- halite inclusions in clusters and trail s; (2) H2O-CO2 inclusions (H2O = 30-60 vol.%) in traits; and (3) H2O-halite inclusions in trails. These fluid generations are explained by trapping at different P-T conditions of two different fluids: a high salinity aqueous fluid and a low salinity H2O-CO2 fluid with XH2O around 0.8. High salinity aqueous fluid inclusions are characteristic for the granite-greenstone cont act and are absent within the Harare-Shamva-Bindura greenstone belt. The hi gh salinity aqueous fluid has, therefore, been interpreted as magmatic in o rigin. The low salinity H2O-CO2 fluid is most likely metamorphic in origin. (C) 1999 Elsevier Science Limited. All rights reserved.