Global Marine Mineral Resources Active
Mineral-laden water emerging from a hydrothermal vent
Hydrothermal vent chimney from the southwest Pacific Ocean
Ferromanganese crust from the south Pacific Ocean
Ferromanganese nodule being sampled from the North Atlantic seafloor
Researching seafloor mineral resources that occur within the U.S. Exclusive Economic Zone and areas beyond national jurisdictions.
Research Overview
The Global Marine Mineral Resources project researches deep ocean minerals within the U.S. Exclusive Economic Zone and throughout the Earth’s oceans. Our research concerns the setting, genesis, and metal enrichment processes of mineral deposits, the relationship between marine minerals related and deep-sea biota, and the potential geochemical footprint of any seafloor mining. We aim to provide stakeholders with the best available science regarding potential resources and environmental impacts associated with accessing those resources.
Project objectives include:
- Geochemical characterization of mineral samples, including mineralogy and metal concentrations, and their variability regionally and globally
- Correlation of oceanographic and geographic parameters with mineralogy and metal content to elucidate the controls on mineral formation and element enrichment, and to map prospective mineral regions within the global ocean
- Investigation of mineral stability and metal mobility with exposure to seawater over time through experimental geochemistry to constrain geochemical effects of mineral disturbance
- Collaboration with biologists to determine associations between minerals and the biological communities which inhabit and surround them
Our findings inform stakeholders, including the public, government, industry, academics and NGOs, about mineral wealth and its environmental setting within the vast offshore territory of the U.S. and helps them determine which regions and deposits may warrant further research.
Seafloor Mineral Deposits
There are a wide variety of deep-sea mineral categories; however, our team focuses on those marine mineral categories that have the greatest resource potential.
Seafloor pavements and encrusted rocks are known as ferromanganese crusts (also called cobalt-rich crusts). These crusts grow very slowly, at several millimeters per million years, and precipitate onto exposed rock surfaces throughout the global ocean—they do not form where sediment blankets the seafloor. In the oldest parts of the seafloor in the northwest Pacific Ocean, some crusts have been forming for over 70 million years and can be over 20 centimeters thick. Crusts act as a sponge of sorts, adsorbing metals and other elements from seawater over these long periods of time, and are especially enriched in cobalt, manganese, rare metals such as tellurium, precious metals such as platinum, and rare earth elements.
Over millions of years, spheroidal rocks called manganese nodules (or polymetallic nodules) form atop sediment covering the abyssal plains of the global ocean. These nodules form by the accretion of iron and manganese oxides around a tiny nucleus, such as a large grain of sand, a shark tooth, or older nodule fragment. Manganese nodules are usually golf-ball to baseball size and grow very slowly like ferromanganese crusts if they acquire all their metals directly from seawater, or they grow faster if they also acquire their metals from the pore-waters of the sediment on which they sit. Nodules are currently of great interest for mining due to high concentrations of manganese, nickel, copper, and sometimes lithium, as well as the straightforward nature of quantifying their distribution and density.
Seafloor massive sulfides (also called polymetallic sulfides) form at hydrothermal vents when seawater penetrates the ocean’s crust and becomes heated and chemically modified through interaction with crustal rocks and, sometimes, by input of magmatic fluids. The hot hydrothermal fluids then rise back toward the seafloor and precipitate minerals as they cool along flow paths and upon mixing with seawater. A wide variety of minerals form through hydrothermal activity, but seafloor massive sulfides are formed from reduced sulfur and may be enriched in copper, zinc, iron, gold, and silver. Hydrothermal vents exist along mid-ocean ridge spreading centers, extensional systems associated with subduction zones, volcanoes, and intraplate hotspots. Yet, seafloor massive sulfides likely extend beyond these active hydrothermal zones. We know the minerals persist after removal from the heat source because of the presence of volcanogenic massive sulfide deposits on land.
Marine phosphorites primarily occur along continental margins where upwelling of cold, nutrient-rich, deep water is strong. These areas include the Peru-Chile margin, on plateaus such as Chatham Rise offshore New Zealand, and the Blake-Bahamas Plateau off the southeast United States; but they can also form on seamounts where ferromanganese crusts grow. Phosphorites form when abundant phosphate in seawater replaces carbonate in calcareous sediments or precipitates in situ as apatite to form hardgrounds, phosphatic nodules, or cements in breccias of multiple rock types. Marine phosphorites are sources of phosphate used as fertilizer for agriculture and phosphoric acid in the food industry. Phosphorites can also contain high concentrations of valuable, heavy, rare earth elements that may be economically recoverable and can contain up to 4% fluorine.
Marine Mining Context
The oceans cover nearly three quarters of the surface of the earth, and in the U.S., the area of seafloor comprising the Exclusive Economic Zone is greater than the land area on shore. This enormous ocean realm hosts many types of minerals that differ from those occurring terrestrially. Ferromanganese crusts, manganese nodules, phosphorites, and hydrothermal vent deposits, which occur from the Arctic to the Antarctic, are enriched in many metals including those currently deemed societally critical. It is therefore important to understand these minerals and the role they may play as future mineral resources.
People around the world demand metals and mineral resources for many uses, including technology, electronics, and green energy infrastructure such as wind turbines and electric cars. Critical minerals are defined as those that are essential to the economic and national security of a nation but that have a supply-chain vulnerable to disruption. In 2018, the Department of the Interior released a list of 54 critical minerals that was further refined to 35 based on Executive Order 13817, with the list to be reconsidered biannually. Across the USGS, research is underway to define and prioritize focus areas throughout the United States with resource potential for these 35 critical minerals. The Global Marine Mineral Resources project specifically informs the marine component.
To date, there is no mining of deep-sea minerals. In Areas Beyond National Jurisdiction, any marine mining is governed by the International Seabed Authority, which is currently drafting exploitation regulations. The Global Marine Mineral Resources project has provided scientific advice to the U.S. State Department and has served as a member of the U.S. delegation to the International Seabed Authority as an Observer Nation for the last 20 years. Japan completed equipment testing offshore of Okinawa in the fall of 2017, recovering 4 tons of metal sulfide. For comparison, it has been suggested that an economic seafloor massive sulfide (SMS) mine would recover on the order of 1 million tons of metal sulfide minerals. There is one permitted mine for copper, gold, and silver offshore Papua New Guinea, on 0.1 square kilometer of seafloor; and the Cook Islands are revising regulations for manganese nodules mining.
Below are other studies related to this project.
Below are data or web applications associated with this project.
Below are multimedia items associated with this project.
Below are publications associated with this project.
Marine ferromanganese encrustations: Archives of changing oceans
Formation of Fe-Mn crusts within a continental margin environment
Ferromanganese crusts and nodules, rocks that grow
News from the seabed: Geological characteristics and resource potential of deep-sea mineral resources
Marine phosphorites as potential resources for heavy rare earth elements and yttrium
What do we really know about the role of microorganisms in iron sulfide mineral formation?
Controls on ferromanganese crust composition and reconnaissance resource potential, Ninetyeast Ridge, Indian Ocean
Manganese nodules
Critical metals in manganese nodules from the Cook Islands EEZ, abundances and distributions
Ocean minerals
Layered hydrothermal barite-sulfide mound field, East Diamante Caldera, Mariana volcanic arc
Below are news stories associated with this project.
- Overview
Researching seafloor mineral resources that occur within the U.S. Exclusive Economic Zone and areas beyond national jurisdictions.
Research Overview
The Global Marine Mineral Resources project researches deep ocean minerals within the U.S. Exclusive Economic Zone and throughout the Earth’s oceans. Our research concerns the setting, genesis, and metal enrichment processes of mineral deposits, the relationship between marine minerals related and deep-sea biota, and the potential geochemical footprint of any seafloor mining. We aim to provide stakeholders with the best available science regarding potential resources and environmental impacts associated with accessing those resources.
Project objectives include:
- Geochemical characterization of mineral samples, including mineralogy and metal concentrations, and their variability regionally and globally
- Correlation of oceanographic and geographic parameters with mineralogy and metal content to elucidate the controls on mineral formation and element enrichment, and to map prospective mineral regions within the global ocean
- Investigation of mineral stability and metal mobility with exposure to seawater over time through experimental geochemistry to constrain geochemical effects of mineral disturbance
- Collaboration with biologists to determine associations between minerals and the biological communities which inhabit and surround them
Our findings inform stakeholders, including the public, government, industry, academics and NGOs, about mineral wealth and its environmental setting within the vast offshore territory of the U.S. and helps them determine which regions and deposits may warrant further research.
Seafloor Mineral Deposits
There are a wide variety of deep-sea mineral categories; however, our team focuses on those marine mineral categories that have the greatest resource potential.
Seafloor pavements and encrusted rocks are known as ferromanganese crusts (also called cobalt-rich crusts). These crusts grow very slowly, at several millimeters per million years, and precipitate onto exposed rock surfaces throughout the global ocean—they do not form where sediment blankets the seafloor. In the oldest parts of the seafloor in the northwest Pacific Ocean, some crusts have been forming for over 70 million years and can be over 20 centimeters thick. Crusts act as a sponge of sorts, adsorbing metals and other elements from seawater over these long periods of time, and are especially enriched in cobalt, manganese, rare metals such as tellurium, precious metals such as platinum, and rare earth elements.
Over millions of years, spheroidal rocks called manganese nodules (or polymetallic nodules) form atop sediment covering the abyssal plains of the global ocean. These nodules form by the accretion of iron and manganese oxides around a tiny nucleus, such as a large grain of sand, a shark tooth, or older nodule fragment. Manganese nodules are usually golf-ball to baseball size and grow very slowly like ferromanganese crusts if they acquire all their metals directly from seawater, or they grow faster if they also acquire their metals from the pore-waters of the sediment on which they sit. Nodules are currently of great interest for mining due to high concentrations of manganese, nickel, copper, and sometimes lithium, as well as the straightforward nature of quantifying their distribution and density.
Seafloor massive sulfides (also called polymetallic sulfides) form at hydrothermal vents when seawater penetrates the ocean’s crust and becomes heated and chemically modified through interaction with crustal rocks and, sometimes, by input of magmatic fluids. The hot hydrothermal fluids then rise back toward the seafloor and precipitate minerals as they cool along flow paths and upon mixing with seawater. A wide variety of minerals form through hydrothermal activity, but seafloor massive sulfides are formed from reduced sulfur and may be enriched in copper, zinc, iron, gold, and silver. Hydrothermal vents exist along mid-ocean ridge spreading centers, extensional systems associated with subduction zones, volcanoes, and intraplate hotspots. Yet, seafloor massive sulfides likely extend beyond these active hydrothermal zones. We know the minerals persist after removal from the heat source because of the presence of volcanogenic massive sulfide deposits on land.
Marine phosphorites primarily occur along continental margins where upwelling of cold, nutrient-rich, deep water is strong. These areas include the Peru-Chile margin, on plateaus such as Chatham Rise offshore New Zealand, and the Blake-Bahamas Plateau off the southeast United States; but they can also form on seamounts where ferromanganese crusts grow. Phosphorites form when abundant phosphate in seawater replaces carbonate in calcareous sediments or precipitates in situ as apatite to form hardgrounds, phosphatic nodules, or cements in breccias of multiple rock types. Marine phosphorites are sources of phosphate used as fertilizer for agriculture and phosphoric acid in the food industry. Phosphorites can also contain high concentrations of valuable, heavy, rare earth elements that may be economically recoverable and can contain up to 4% fluorine.
Marine Mining Context
The oceans cover nearly three quarters of the surface of the earth, and in the U.S., the area of seafloor comprising the Exclusive Economic Zone is greater than the land area on shore. This enormous ocean realm hosts many types of minerals that differ from those occurring terrestrially. Ferromanganese crusts, manganese nodules, phosphorites, and hydrothermal vent deposits, which occur from the Arctic to the Antarctic, are enriched in many metals including those currently deemed societally critical. It is therefore important to understand these minerals and the role they may play as future mineral resources.
People around the world demand metals and mineral resources for many uses, including technology, electronics, and green energy infrastructure such as wind turbines and electric cars. Critical minerals are defined as those that are essential to the economic and national security of a nation but that have a supply-chain vulnerable to disruption. In 2018, the Department of the Interior released a list of 54 critical minerals that was further refined to 35 based on Executive Order 13817, with the list to be reconsidered biannually. Across the USGS, research is underway to define and prioritize focus areas throughout the United States with resource potential for these 35 critical minerals. The Global Marine Mineral Resources project specifically informs the marine component.
To date, there is no mining of deep-sea minerals. In Areas Beyond National Jurisdiction, any marine mining is governed by the International Seabed Authority, which is currently drafting exploitation regulations. The Global Marine Mineral Resources project has provided scientific advice to the U.S. State Department and has served as a member of the U.S. delegation to the International Seabed Authority as an Observer Nation for the last 20 years. Japan completed equipment testing offshore of Okinawa in the fall of 2017, recovering 4 tons of metal sulfide. For comparison, it has been suggested that an economic seafloor massive sulfide (SMS) mine would recover on the order of 1 million tons of metal sulfide minerals. There is one permitted mine for copper, gold, and silver offshore Papua New Guinea, on 0.1 square kilometer of seafloor; and the Cook Islands are revising regulations for manganese nodules mining.
- Science
Below are other studies related to this project.
- Data
Below are data or web applications associated with this project.
- Multimedia
Below are multimedia items associated with this project.
- Publications
Below are publications associated with this project.
Filter Total Items: 55Marine ferromanganese encrustations: Archives of changing oceans
Marine iron–manganese oxide coatings occur in many shallow and deep-water areas of the global ocean and can form in three ways: 1) Fe–Mn crusts can precipitate from seawater onto rocks on seamounts; 2) Fe–Mn nodules can form on the sediment surface around a nucleus by diagenetic processes in sediment pore water; 3) encrustations can precipitate from hydrothermal fluids. These oxide coatings have bAuthorsAndrea Koschinsky, James R. HeinFormation of Fe-Mn crusts within a continental margin environment
This study examines Fe-Mn crusts that form on seamounts along the California continental-margin (CCM), within the United States 200 nautical mile exclusive economic zone. The study area extends from approximately 30° to 38° North latitudes and from 117° to 126° West longitudes. The area of study is a tectonically active northeast Pacific plate boundary region and is also part of the North PacificAuthorsTracey A. Conrad, James R. Hein, Adina Paytan, David A. ClagueFerromanganese crusts and nodules, rocks that grow
Ferromanganese (Fe-Mn) crusts and nodules are marine sed- imentary mineral deposits, composed mostly of iron and manganese oxides. They precipitate very slowly from seawa- ter, or for nodules also from deep-sea sediment pore waters, recording the chemical signature of these source waters as they grow. Additional elements incorporate via sorption pro- cesses onto the Fe-Mn oxides, including rare anAuthorsKira Mizell, James R. HeinNews from the seabed: Geological characteristics and resource potential of deep-sea mineral resources
Marine minerals such as manganese nodules, Co-rich ferromanganese crusts, and seafloor massive sulfides are commonly seen as possible future resources that could potentially add to the global raw materials supply. At present, a proper assessment of these resources is not possible due to a severe lack of information regarding their size, distribution, and composition. It is clear, however, that manAuthorsSwen Petersen, Anna Kratschell, Nico Augustin, John Jamieson, James R. Hein, Mark D. HanningtonMarine phosphorites as potential resources for heavy rare earth elements and yttrium
Marine phosphorites are known to concentrate rare earth elements and yttrium (REY) during early diagenetic formation. Much of the REY data available are decades old and incomplete, and there has not been a systematic study of REY distributions in marine phosphorite deposits that formed over a range of oceanic environments. Consequently, we initiated this study to determine if marine phosphorite deAuthorsJames R. Hein, Andrea Koschinsky, Mariah Mikesell, Kira Mizell, Craig R. Glenn, Ray WoodWhat do we really know about the role of microorganisms in iron sulfide mineral formation?
Iron sulfide mineralization in low-temperature systems is a result of biotic and abiotic processes, though the delineation between these two modes of formation is not always straightforward. Here we review the role of microorganisms in the precipitation of extracellular iron sulfide minerals. We summarize the evidence that links sulfur-metabolizing microorganisms and sulfide minerals in nature andAuthorsAude A. Picard, Amy Gartman, Peter R. GirguisControls on ferromanganese crust composition and reconnaissance resource potential, Ninetyeast Ridge, Indian Ocean
A reconnaissance survey of Fe-Mn crusts from the 5000 km long (~31°S to 10°N) Ninetyeast Ridge (NER) in the Indian Ocean shows their widespread occurrence along the ridge as well as with water depth on the ridge flanks. The crusts are hydrogenetic based in growth rates and discrimination plots. Twenty samples from 12 crusts from 9 locations along the ridge were analyzed for chemical and mineralogiAuthorsJames R. Hein, Tracey A. Conrad, Kira Mizell, Virupaxa K. Banakar, Frederick A. Frey, William W. SagerManganese nodules
The existence of manganese (Mn) nodules (Figure 1) has been known since the late 1800s when they were collected during the Challenger expedition of 1873–1876. However, it was not until after WWII that nodules were further studied in detail for their ability to adsorb metals from seawater. Many of the early studies did not distinguish Mn nodules from Mn crusts. Economic interest in Mn nodules beganAuthorsJames R. HeinCritical metals in manganese nodules from the Cook Islands EEZ, abundances and distributions
The Cook Islands (CIs) Exclusive Economic Zone (EEZ) encompasses 1,977,000 km2 and includes the Penrhyn and Samoa basins abyssal plains where manganese nodules flourish due to the availability of prolific nucleus material, slow sedimentation rates, and strong bottom currents. A group of CIs nodules was analyzed for mineralogical and chemical composition, which include many critical metals not befoAuthorsJames R. Hein, Francesca Spinardi, Nobuyuki Okamoto, Kira Mizell, Darryl Thorburn, Akuila TawakeOcean minerals
Nearly 71 percent of the Earth is covered by ocean, yet during the entire history of societies, the mineral resources essential for nation building have been acquired solely from the continents. Deep-ocean minerals were discovered over a century ago during the Challenger expedition of 1873—1876, but only relatively recently did programs develop to determine their origin, distribution, and resourceAuthorsJames R. Hein, Kira L. MizellLayered hydrothermal barite-sulfide mound field, East Diamante Caldera, Mariana volcanic arc
East Diamante is a submarine volcano in the southern Mariana arc that is host to a complex caldera ~5 × 10 km (elongated ENE-WSW) that is breached along its northern and southwestern sectors. A large field of barite-sulfide mounds was discovered in June 2009 and revisited in July 2010 with the R/V Natsushima, using the ROV Hyper-Dolphin. The mound field occurs on the northeast flank of a cluster oAuthorsJames R. Hein, Cornel E. J. de Ronde, Randolph A. Koski, Robert G. Ditchburn, Kira Mizell, Yoshihiko Tamura, Robert J. Stern, Tracey Conrad, Osamu Ishizuka, Matthew I. Leybourne - News
Below are news stories associated with this project.
Filter Total Items: 18