WHAT ARE SEABED
MINERALS?
Mineral Basics
Mineral Deposits form on the seafloor as a result of a variety of processes that all result in the precipitation of metalliferous materials. These products can be used in industries ranging from jewellery, construction and modern technology.
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Cobalt Ore
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Earths Tectonic Plates
Tectonic Plates
The Earths Crust compromises of seven major tectonic plates and a number of micro-plates who’s movement is driven by convection currents in the Earth’s mantle. At the boundaries of these plates, sections of crust meet at transient, diverging and converging margins. This leads to the formation of a variety of geological formations including faults, volcanoes and mountains. Spreading occurs at both diverging boundaries such as the Mid-Atlantic Ridge and behind subduction zones, in a process known as back-arc extensions. When these processes incorporate seawater, we can get submarine ore deposits.
SEABED
MINERAL USES
FIND OUT HOW SEABED MINERALS ARE USED IN EVERY DAY LIFE
Zinc
Alloys, Batteries and Sun Cream
Manganese
Mobile Phones and the Production of Steel
Cobalt
Construction, Magnets and Paint
Gold
Dentistry, Medicine and Jewellery
Nickel
Aerospace and Chemicals
Silver
Photography, Electrical Wires and Crockery
Copper
Electricals and General Produce
ORES OF
INTEREST
Seafloor Massive Sulfides
When two plates drift apart, hot magma rises to the surface as it decompresses. Meanwhile, the seawater above is drawn down to the subsurface. This water rises upon heating and cycles back up through the Stockwork Zone. The flow of these hot, concentrated fluids leads to the alteration of the shallow crust below the surface. This is because the power of these rising fluids fractures the old, cooled pillow lavas, stripping them of their elements via dissolution and re-precipitating these metals elsewhere in the system, creating a vein-like structure, often rich in iron ores.
This seawater continues to rise upon heating and erupts as a “dusty” material as contact with the cooler seawater triggers the precipitation of dissolved minerals. Commonly known as “Black Smokers”, these deposits settle onto the seafloor and form ore bodies that are often rich in Cu, Au, Zu and Ag.
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Seafloor Sulfide – Galena
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Fine Manganese
Manganese
Sediment deposited on the sea floor can be of terrigenous or biogenic marince source. After this sediment falls to the base of the ocean, over time it becomes cemented. When sedimentation rates slow, soft, young sediment is not laid down above the older, hard, cemented sediment. Mn ores grow very slowly and are preferentially precipitated in ultra-deep waters, below the Oxygen Minimum Zone (OMZ). This is considered the most important source of dissolved MN, commonly from decompressed organic matter.
Manganese Nodules
These ultra-deep depths also lie below the CCD (Calcite Compensation Depth). This is the depth at which Calcium Carbonate dissolves entirely. Many marine organisms have shells formed of Calcium Carbonate and when they die, this material sinks to the bottom of the ocean, however, at these depths, the calcium carbonate is dissolved before it can get there. This slows sedimentation rates and means Mn nodules and FeMn crusts are preferentially precipitated from seawater at ultra-deep depths and able to nucleate on the hard seafloor substrate.
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Manganese Nodules
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