Deep sea minerals
Prelims and MainsCurrent affairs on this: Ocean, polar and earth science missions
Two kinds of deposit are worth going to the ocean floor for, and they form in different places. The figure compares them.
Nodules and sulphides
Polymetallic nodules
- Lumps growing very slowly on abyssal plains, 3,000 to 6,000 m deep
- Manganese, nickel, cobalt, copper
Polymetallic sulphides
- Deposits at hydrothermal vents along a mid-ocean ridge, where plates move apart
- Copper, zinc, gold, silver
- Polymetallic nodules, potato sized lumps rich in manganese, nickel, cobalt and copper, settle grain by grain over millions of years on flat abyssal plains at 4,000 to 6,000 metres.
- Polymetallic sulphides are thrown out at hydrothermal vents along the ridges where plates pull apart, and carry copper, zinc, gold and silver.
- Cobalt rich crusts on seamounts are the third type.
Background reading: PIB, 8 Sep 2026: Ministry of Earth Sciences and NIOT Host Industry Outreach Workshop on Deep Sea Mining to Secure India's Critical Mineral Future (opens in a new tab)
See also: UNCLOS: the zones from the coast to the Area · India's deep sea mining programme · Deep Ocean Mission