Deep-ocean footage has a certain kind of silence. There is no wind. No background noise. Just a remote-controlled vehicle slicing through pitch-black water, its lights grazing the edges of rock formations that haven’t seen anything in millions of years, not even light. That’s about what scientists saw during NOAA’s most recent deep-sea survey operations off the coast of Hawaii, and what the cameras captured has forced geologists into unsettling but fascinating territory.
The results were not presented in a single, dramatic moment. Through NOAA’s ongoing Beyond the Blue campaign and its Ocean Exploration Cooperative Institute missions, which have been methodically mapping uncharted zones within the U.S. Exclusive Economic Zone, they accumulated, dive by dive. These dives off the Hawaiian Islands and throughout the Papahānaumokuākea Marine National Monument have revealed an underwater geology picture that is more intricate, multilayered, and, to be honest, bizarre than anyone had ever imagined.
One of the most remarkable findings was the imagery of nearly 49-foot-tall volcanic dikes, which are massive underwater monoliths created when magma pushes through fissures in the ocean’s crust and solidifies mid-fracture, taken by ROVs surveying deep Pacific waters. Such detailed documentation of these structures is uncommon. It’s difficult to ignore the magnitude of geological time as you watch the video. Researchers can see how magma actually moves beneath the Pacific plate thanks to the dikes, and some of what they see doesn’t quite fit the current models of how oceanic crust deforms under pressure.
Then there’s the formation that, at cocktail parties, people actually find it difficult to explain themselves. When the research vessel E/V Nautilus explored a section of the seafloor along the Liliʻuokalani Ridge, it discovered what appears to be a paved road made of yellow bricks: neat, square, fractured volcanic rock arranged in patterns created by repeated cycles of heating and cooling over deep time. Scientists quickly pointed out that it’s completely natural. Nevertheless, it’s the kind of image that resonates with you. There is a feeling that the ocean floor has the power to defy our expectations when it so chooses.
The thorough mapping of polymetallic nodule fields throughout the abyssal plains may be the most significant discovery for businesses and policymakers, even though it takes longer to make news. Cobalt, manganese, nickel, and other elements that the clean energy industry has been covertly monitoring are found in these lumpy mineral deposits, which are dispersed throughout the seafloor at depths where no light can reach. Knowing how these nodules develop modifies the geological models that scientists employ to forecast their concentration and rate of accumulation. Additionally, it reignites discussions about deep-sea mining that have never been fully settled.
The scope of what is still unknown, rather than just the particular objects discovered, is what makes NOAA’s New Deep-Sea Survey Off Hawaii so important. Only about 20% of the world’s seafloor has been high-resolution mapped. One of the biggest understudied areas under U.S. ocean jurisdiction is the Hawaiian abyssal plain, which stretches through deep Pacific waters south of the islands. Together with NOAA teams, USGS scientists have been using environmental DNA sampling in conjunction with sonar mapping to detect genetic traces of organisms moving through the water column—species that don’t require physical capture. There’s a chance that some of what they’re discovering biologically is connected to the geological activity below in ways that are still unknown.
Whether these discoveries will significantly alter plate tectonic theory or merely close gaps that geologists already suspected existed is still up for debate. However, those who have been closely monitoring these expeditions feel that the Pacific floor surrounding Hawaii has been concealing a more dynamic and complex geological narrative than the surface maps have ever indicated. It turns out that the best material in the ocean is found far below the waterline.
