ORE-FORMING PROCESSES IN THE SOUTH ATLANT IC MAGMATIC AND HYDROTHERMAL SYSTEMS (BOUVET TRIPLE JUNCTION)

Investigation of a collection of rocks with ore and hydrothermal miner als gathered during the 18th cruise of the research vessel <<Akademik Nikolai Strakhov>> (1994) at the Bouvet Triple Junction provided new d ata on composition of sulfides and characteristic distribution of gold in magmatic associations. Liquid CO2 inclusions have first been found for the lithosphere of modern oceans; they indicate a considerable ro le of CO2 in hydrothermal systems near the Bouvet hotspot. According t o data of analysis of CO2 and water solution inclusion, parameters of H2O-CO2 fluids that formed quartz from sulfide ore have been determine d (NaCl+CaCl2+H2O+CO2; T = = 200-310 degrees C, P = 900-1700 bars). It has been established that water solutions close to composition to sea water (NaCl + MgCl2+H2O) with temperatures of 170-200 degrees C are p redominant in hydrotherms with insignificant contents of ore component s.