Sedimentary characteristics based on sub-bottom profiling and the implications for mineralization of cobalt-rich ferromanganese crusts at Weijia Guyot, Western Pacific Ocean

Abstract

Cobalt-rich ferromanganese crusts on seamounts have attracted much attention due to high economic potential of various metals. Studies showed that seamounts in the Western Pacific Ocean are rich in cobalt-rich crusts, and Weijia Guyot (Ita Mai Tai) is one of the most promising one. Cobalt-rich crusts were drilled from this seamount in our previous investigation. This study evaluates promising areas of cobalt-rich crusts on the whole guyot. Combined the sub-bottom profiles, topography, scientific ocean drilling data with related studies, this paper studied sedimentary characteristic and their implications for cobalt-rich crusts mineralization prospective areas on the summit of Weijia Guyot. Three types of stratum reflection characteristics were identified: pelagic deposits, oolitic limestone, and lagoonal mud. Reflection sequences in Chirp sub-bottom profiler records are well matched to stratigraphy obtained at Deep-Sea Drilling Project Sites 200 and 202. Cobalt-rich crusts promising mineralization areas were delineated based on the water depth, slope gradient and pelagic pinch-out line, with the area approximately 576.4 km2. This estimated number is 10% higher than the results from previous studies (approximately 436.6 km2). It provides great implication for exploration and mining-lease-block selection in the future.