Distribution characteristics of cobalt-rich ferromanganese crust resources on submarine seamounts in the Western Pacific

Based on the survey data of five submarine seamount provinces (chains) in the Western Pacific, the distribution characteristics of cobalt-rich ferromanganese crust resources have been researched in this paper by using the relative reference data and applying the theories of hotspot and seafloor spreading. The main research results obtained are as follows: The Co-rich crust thickness in the study area is gradually increasing from east to west and from south to north having a negative correlation (r = -0.59) with longitude and a positive correlation (r = 0.48) with latitude. The crust thickness varying along longitude and latitude is influenced by the hotspot and seafloor spreading. The oceanic crusts and seamounts in the northwest part of the study area are older, and the crust resources are superior to those in the southeast part. In the depth of < 1500 m, 1500-2000 m, 2000-2500 m in the study area, the cobalt crust thickness is respectively 5.45 cm, 4.34 cm and 3.55 cm, and in the depth of 2500-3000 m and 3000-3500 m, it drops respectively to 2.84 cm and 3.37 cm. The Co-rich crust resources are mainly concentrated in the seamount summit margins and the upper flanks in the depth of < 2500 m. There is a strong negative correlation (r = -0.67) between the cobalt crust abundance and the slope of the seamount, 75 kg/m(2) and 50 kg/m(2) at the slopes of 0 degrees-20 degrees and 20 degrees-34 degrees respectively. Cobalt crusts are mainly distributed in the parts whose slopes are less than 20 degrees. It is consistent with the fractal result that the slope threshold of cobalt crust distribution is 19 degrees, and slopes over 20 degrees are not conducive to the crust growth. The cobalt crusts of high grade are mainly enriched in the region within 150 degrees E-140 degrees W and 30 degrees S-30 degrees N in the Pacific, where there are about 587 seamounts at the depth of 35006000 m and over 30 Ma of the oceanic crusts. The perspective area rich in cobalt crust resources is about 41x10(4) km(2) and the resource quantity is approximately 27 billion tons.