Hydrothermal Sulfides along Mid-Ocean Ridge: Tremendous Temptation to Human Being
Huaiyang Zhou
State Key Lab of Marine Geology, Tongji University, Shanghai 200092
Since first discovery of hydrothermal activity at Galapogos in 1978, it has been known that there are more than 400 hydrothermal sites distributed along about 60000 km length of mid-ocean ridge. Among them, about 140 is of economic potential with polymetallic sulfide minerals. The largest known hydrothermal sulfide deposit is TAG (Trans-Atlantic Geotraverse) in the rift valley of the Mid-Atlantic Ridge which has about 10 million tonnage of ores. Based on principle of “common heritage of mankind” and UNCLOS (United Nations Convention on the Law of the Sea), the International Seabed Authority is currently working on “Draft regulations on prospecting and exploration for polymetallic sulphides in the Area” which allow exclusive right of exploration and exploitation of applicants for polymetallic sulfide resources in the Area.
However, although possible huge ore deposits are promised with the degree of exploration along mid-ocean ridge in near future, amount of metals and their economic value of known hydrothermal sulfide deposits are quite limited compared with the large massive sulfide deposits on land (in Canada, Russia, China, for example), not even mention that deep sea mining technology is still not existed.
In comparison, scientific significance of hydrothermal sulfides and associated ecosystem is multiple and invaluable. The hydrothermal system is a unique window for scientists over the world to study geological and biological processes new to human being and get analogous tracers for the studies on land and even the early history of the earth.
On other hand, genetic resources from chemosynthesis-based and diversed ecosystem which associated with dynamic hydrothermal activity are unfortunately beyond the legal framework of UNCLOS up to date. The impacts of exploration and exploitation of hydrothermal sulfide minerals on these precious ecosystems is unknown and never evaluated. Nevertheless, it is proposed that we should be very careful and slow down the international legal work to encourage the potential exploitation of hydrothermal sulfides before the fascinated system be well scientifically studied. Another side of “common heritage of mankind” should be “common responsibility of mankind”.