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Petrographic (A, D) SEM (B, E) and STEM (C, F) images of bladed marcasite (A, B,C) and bladed pyrrhotite (D,E,F). The petrographic images are reflected light under plane polarization. The brassy minerals in D are isocubanite being replaced by chalcopyrite. (Image credit: USGS)

USGS Study Flags Spontaneous Combustion Risk in Seafloor Massive Sulfide Mining

A field of polymetallic nodules seen during Dive 04 of the 2026 American Samoa ROV + Mapping Exploration expedition at a depth of approximately 5,140 meters (3.2 miles). (Credit: USGS)

USGS Tests Radon as a Geochemical Tracer for Deep-Sea Polymetallic Nodules
A stratigraphic scanning electron microscope tour showing the evolution of manganese-oxide mineralization of host sediment. Mn mineralization shows a multipronged process of formation including growth of Mn columns in soft sediment, cementation and then partial to complete replacement of the host sediment, Mn grain growth, Mn recrystallization, and late-stage void-fracture fill. Click image for full explanation. A new study led by USGS describes a previously undocumented style of hydrothermal manganese-oxide mineralization on the seabed near American Samoa, offering new insight into how seafloor mineral occurrences can form and how widespread similar deposits may be around the world. The study examined 24 dredge samples collected from three sites along the Samoan volcanic chain in the South Pacific. In many of these samples, researchers found evidence that hot, mineral-rich fluids moved upward through seafloor sediments, progressively replacing the original material with thick layers of manganese-oxide minerals. Hydrothermal systems occur where heated fluids circulate through Earth's crust and return to the seafloor, carrying dissolved metals and other elements. When those fluids encounter cooler surroundings, minerals can precipitate and accumulate. Manganese oxides are common components of seafloor mineral occurrences, but the new study documents something researchers had not previously observed: hydrothermal manganese oxides replacing sediment made up of foraminiferal carbonate. Foraminifera are microscopic marine organisms whose shells are commonly composed of calcium carbonate and can accumulate on the seafloor after the organisms die. (Credit: USGS)

USGS Documents Novel Seafloor Manganese-Oxide Deposits Near American Samoa
(Image credit: ISA)

South Korea Opens Five At-Sea Training Spots for ISA Cobalt Crust Exploration Program
(Image credit: ISA)

ISA Taxonomy School Trains 25 Scientists in Deep-Sea Biodiversity Methods

ISA–China Joint Training Center Opens Deep-Sea Data Research Proposals
The remotely operated vehicle, Deep Discoverer, imaging the seafloor off American Samoa during an expedition in 2017. (Image credit: NOAA OER)

Okeanos Explorer to Chart Deep-Sea Critical Minerals Near American Samoa
ISA Celebrates Sustainable Seabed Knowledge Initiative Milestones in Deep-Sea Biodiversity Research

ISA Celebrates Sustainable Seabed Knowledge Initiative Milestones in Deep-Sea Biodiversity Research
Scientific drilling vessel Chikyu. (Image credit: JAMSTEC)

Minamitori Island Seabed Mud Yields Heavy Rare Earths Ahead of 2027 Mining Trial
(Image credit: ISA)

ISA Workshop Targets Deep-Sea Taxonomy Standards for Seabed Mining Oversight
Newly identified deep-sea amphipod, Caeconyx papso.

Deep-Sea Amphipod Discovery Highlights Abyssal Plain Biodiversity Gaps
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