Marine Placer

Marine placer styles of mineralization are the product of erosion, transportation, and re-deposition of mineral concentrations from primary terrestrial source areas to locations in the marine environment. A wide suite of marine placer mineral concentrations exist, where mineral species are refractory, stable minerals composed of light to heavy elements. Placer mineralization can include: titanium and iron (heavy and light mineral sands, respectively), gold and silver, platinum, tin, rare earth elements (monazite, zircon), precious stones (ruby, sapphire, diamond) and industrial minerals such as limestone and silica (quartz). Concentrations of placer minerals are typically located in shallow water along continental margins where enrichment may have occurred owing to fluvial or submarine coastal dynamic processes and changes in sea level. 

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Polymetallic Crusts

Polymetallic crusts represent accumulations of manganese and iron framework mineral oxides containing elevated contents of cobalt, nickel, copper, molybdenum, rare earth elements, yittrium, tellurium, platinum, and other critical metals. They are identified throughout the world’s oceans and are also referred to as cobalt-rich crusts. Polymetallic crusts form thin layers typically less than 25 centimeters thick on surfaces of seamounts, ridges, and plateaus in places where sediments do not accumulate. Crusts of economic interest occur on very large, old, flat-topped seamounts called guyots at water depths between 1200 to 2500 meters. Metals are sourced entirely from cold, ambient bottom seawater. Prevailing water masses create obstructional upwelling and turbulence when inpinging on a seamount that prevents the accumulation of sediment and consequent burial of the crusts. 

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Polymetallic Sulfides

Polymetallic sulfides are mineral deposits found on and below the ocean floor.  They contain copper, zinc, gold, silver, and other trace metals.  They are commonly referred to as seafloor massive sulfides, or SMS, regardless of how they formed or where they occurred.  There are different styles of mineralization primarily influenced by geographic and tectonic setting, and metal enrichments that depend on fluid temperature, phase separation, host-rock type, and other conditions. Deposit types include hybrid epithermal-porphyry, sedimentary exhalative deposits, and seafloor massive sulfides (SMS) associated with hydrothermal-fluid precipitating sulfide deposits. SMS deposits are found in areas of active or complex tectonic or volcanogenic activity, such as near oceanic spreading centers (such as the Mid-Atlantic Ridge and East Pacific Rise), back-arc basins (such as the Manus Basin in Papua New Guinea’s EEZ), and submarine arc volcanic chains (such as Izu-Bonin-Mariana Arc in the NW Pacific).  Odyssey has extensive experience in the discovery and evaluation of polymetallic sulfide systems, having worked in several jurisdictions of the western South Pacific.