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Paper Number: 122
Quantitative
prediction and evaluation of seafloor hydrothermal sulfide resources in
the Indian Ocean
Chen, J.P.1,2,3, Ren, M.Y.1,2,3, Shao
K.1,2,3
1
School of Earth Sciences and Resources, China University of Geosciences,
Beijing 10083, China
2
Institute of Land Resources and High Techniques, China University of
Geosciences, Beijing 10083, China
___________________________________________________________________________
Seafloor hydrothermal sulfide resources have attracted significant
attention as a potential seabed mineral resource due to their high grade
of precious metal elements, such as Cu, Zn, Pb, Au, and Ag. In 2011, the
China Ocean Mineral Resources Research and Development Association and
International Seabed Authority signed a contract for exploration 10,000
km2 of a hydrothermal sulfides area located on the Southwest
Indian Ridge, and only 25% of the area will be permitted to retain in
2021(Hannington et al; Tao et al). The best approach for rapidly and
accurately searching for seafloor hydrothermal sulfide resources has
become a top priority.
According to the quantitative prediction theory and the exploration
status of seafloor sulfides, we systematically proposes a quantitative
prediction evaluation process of oceanic hydrothermal sulfide resources
and divides it into three stages: prediction in a large area, prediction
in the prospecting region, and the verification and evaluation of
targets(Ren et al). This paper mainly focuses on the first stage and
select the Indian Ocean to be the prediction area.
Indian Ocean, the youngest oceans on earth, is located between Asia,
Oceania, Africa and Antarctica, accounting for about 20% of the world‘s
total area of the sea. It belongs to super slow spreading mid-ocean
ridge(Dick and Schouten). The dynamic volcanic and tectonic activity in
some segments make it possible for hydrothermal systems to have heat and
fluid flow channels. Ore-forming factors are collected from topography,
geology, geophysics, and several other related aspects. We obtain the
key prediction factors that exhibit the greatest relevance to the
formation of sulfide deposit to derive a favourable metallogenic
combination. By employing the method of weights-of-evidence, the
prediction result suggests that the SWIR and the junction of trigeminal
ridges yield a relatively high value, which can be selected as a
promising prospecting region. Known hydrothermal areas such as Mt.
Jourdanne, area A , Edmond and Kariei are all located in the areas with
high posterior probability value. It also illustrates that the predicted
result possesses a superior reliability. The Chinese contract area is
located in the central SWIR, where the value of posterior probability is
significant; this finding indicates superior prospecting potential and
an accurate and meaningful selection of its location. By narrowing the
exploration area and improving the exploration accuracy, the prediction
will provide a basis for the further exploration of seafloor
hydrothermal sulfide resources.
References:
[1]Hannington M, Jamieson J, Monecke T, et al.,2011, The abundance of
seafloor massive sulfide deposits. Geology, 39(12): 1155-1158.
[2]Tao, C H, Li, H M, Jin, X B, et al., 2014, Seafloor hydrothermal
activity and polymetallic sulfide exploration on the southwest Indian
ridge, Chinese Science Bulletin, 59, 2266–2276.
[3]Ren M Y, Chen J P, Shao K, et al., 2015, Quantitative prediction
process and evaluation method of seafloor polymetallic sulfide
resources, Geoscience Frontiers (in press)
[4]Dick H J B, Lin J, Schouten H, 2003, An ultraslow-spreading class
of ocean ridge, Nature, 426(27): 405-412.
