See a larger version of this bed of manganese nodules, from deep offshore of the Cook Islands.
Countries around the world need metals and minerals to satisfy our burgeoning technology and electronic needs. Even green technologies, such as windmills and electric cars, require large quantities of metals that are often rare and energy intensive to source on land.
As terrestrial sources of these materials dwindle (China produces most of what the U.S. imports), the mining focus has shifted to the unseen parts of our planet that hold potentially larger mineral stores: the deep sea. Iron-manganese crusts, manganese nodules, phosphorites, and hydrothermal vent deposits are four sources of important metals and minerals found on the seafloor. Although mining in the ocean has advantages over mining on land (extraction requires a smaller footprint, for example), economic and technological hurdles as well as environmental concerns have yet to be resolved. Despite these obstacles, the first section of ocean—0.1 square kilometer off Papua New Guinea—was set to be commercially mined in early 2018. Financing the project has proven difficult, delaying the start date to early 2019.
USGS provides expertise in analyzing the metals and other elements in these mineral deposits, which occur in many deep-ocean settings from the Arctic to the Antarctic. USGS also researches environmental issues related to their recovering the mineral resources these deposits contain. Knowing their attributes and how these features form on the seafloor benefits many agencies, including the International Seabed Authority, which regulates mining in international waters and areas leased within a country’s Exclusive Economic Zone. USGS information about deep ocean minerals helps guide stakeholders to make informed decisions on environmental issues, resource use, and energy production.
Photographs of example Cook Islands manganese nodules from “Critical metals in manganese nodules from the Cook Islands EEZ, abundances and distributions,” Ore Geology Reviews v.68 (2015), by Hein and others, online at doi:10.1016/j.oregeorev.2014.12.011.
The goals of the Global Ocean Minerals Study are to
Interest in mining seafloor massive sulfides (SMS), which occur as a result of hydrothermal activity in the global ocean, is increasing and will likely begin in earnest within the next several years. The geochemical and environmental implications of this exploitation have not been constrained. The mining of SMS deposits will likely create a new class of abundant micron and sub-micron sized metal sulfide particles. These new particulates may potentially be more reactive than naturally occurring particles, with regard to oxidation and microbial colonization. This Mendenhall Postdoctoral project will evaluate the local-to-global geochemical consequences of the alteration of sulfide particles likely to occur as a result of SMS mining relative to similar particles emitted from natural hydrothermal systems, and will consider potential environmental perturbations due to SMS resource extraction.
The goals of this project are to:
Arctic Deep-Water Ferromanganese-Oxide Deposits Reflect the Unique Characteristics of the Arctic Ocean - Geochemistry, Geophysics, Geosystems, 2017
Distance-gradient-based variogram and Kriging to evaluate cobalt-rich crust deposits on seamounts - Ore Geology Reviews, 2017
Marine mineral deposits: New resources for base, precious, and critical metals. Ore Geology Reviews - Ore Geology Reviews, 2017
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