RESOURCE ESTIMATION OF THE SULFIDE-RICH DEPOSITS OF THE YUHUANG-1 HYDROTHERMAL FIELD ON THE ULTRASLOW-SPREADING SOUTHWEST INDIAN RIDGE

Abstract

SEAFLOOR MASSIVE SULFIDE (SMS) DEPOSITS ARE IMPORTANT DEEP-SEA MINERAL RESOURCES EXPECTED TO OCCUR PREDOMINANTLY ON SLOW- AND ULTRASLOW-SPREADING MID-OCEAN RIDGES. RESOURCE ESTIMATES ARE ALREADY AVAILABLE FOR SOME OF THE LARGEST SMS DEPOSITS ON SLOW-SPREADING RIDGES BUT NOT ON ULTRASLOW-SPREADING RIDGES. BASED ON GEOLOGICAL MAPPING AND SAMPLING, THIS STUDY INVESTIGATES THE DISTRIBUTION AND CONTENT OF SULFIDE-RICH DEPOSITS IN THE YUHUANG-1 HYDROTHERMAL FIELD (YHF), LOCATED ON THE ULTRASLOW-SPREADING SOUTHWEST INDIAN RIDGE. THE SULFIDE-RICH DEPOSITS IN THE YHF ARE COMPOSED OF TWO AREAS ∼500 M APART: THE SOUTHWEST SULFIDE AREA (SWS) AND THE NORTHEAST SULFIDE AREA (NES). WE CALCULATED THE VOLUME OF SULFIDE-RICH MOUNDS IN THE YHF AND ARRIVED AT A TOTAL ACCUMULATION OF ∼10.6 × 106 TONS, INCLUDING AT LEAST ∼7.5 × 105 TONS OF COPPER AND ZINC AND ∼18 TONS OF GOLD. FURTHERMORE, CONSIDERING THE COVERAGE OF LAYERED HYDROTHERMAL SEDIMENT MIXED WITH SULFIDE-RICH BRECCIAS, WHICH MAY HAVE UNDERLYING MASSIVE SULFIDE DEPOSITS, THE MAXIMUM TOTAL MASS WAS ESTIMATED AT ∼45.1 × 106 TONS. THIS SUGGESTS THAT THE YHF IS ONE OF THE LARGEST SMS DEPOSITS WORLDWIDE AND CONFIRM THAT ULTRASLOW-SPREADING RIDGES HAVE THE GREATEST POTENTIAL TO FORM LARGE-SCALE SMS DEPOSITS.