FLUID INCLUSIONS IN QUARTZ-PEBBLES OF THE GOLD-BEARING TARKWAIAN CONGLOMERATES OF GHANA AS GUIDES TO THEIR PROVENANCE AREA

Quartz-pebbles of the early Proterozoic Au-bearing Tarkwaian conglomer ates in Ghana reveal several original (inherited) pre-sedimentary flui d inclusions. These inclusions are CO2-N-2 rich and display a distinct high density (up to 1.15 g/cm(3)). The unusual high density and compo sition compare well with CO2-N-2-rich inclusions in quartz-vein type g old deposits of the Birimian Supergroup in Ghana and Burkina Faso. Thi s type of fluid inclusions has not been reported from any other lode-g old deposit of greenstone affiliation and is thus a specific character istic for Birimian-hosted gold deposits. Therefore, it can be used as an unequivocal pathfinder for epigenetic as well as for syn-sedimentar y gold mineralization of the early Proterozoic of West Africa. The inh erited fluid inclusions with the unique physicochemical characteristic s suggest that the Tarkwaian quartz-pebbles and possibly some gold wer e derived from Au-quartz vein deposits comparable in mineralogy, petro graphy and genesis to those along the NW-margin of the Ashanti belt (e .g. Ashanti Mine, Prestea Mine).