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Gulf of Alaska Seamount Chains


Mountain ranges aren't only on land—indeed, some of the world's biggest mountain ranges occur in the ocean! Underwater mountains called seamounts rise high above the surrounding seafloor. Most of these are extinct volcanoes that formed above "hotspots" of magma rising from deep within the Earth. Beneath the waves in the Gulf of Alaska stretch long chains of seamounts. The crest of one such peak, Patton Seamount, reaches to within 600 feet of the surface. Over 10,000 feet tall and 20 miles wide at the base, Patton Seamount originally formed off Washington state as a submerged volcano 33 million years ago. Over time, as the Pacific Plate moved steadily northwest, Patton Seamount was carried off the hotspot and into the Gulf of Alaska. New volcanoes formed one after another over this hotspot, producing today's seamount chain. Explorations of these seamounts in the Gulf of Alaska have shown that despite the fact that most of these Pacific seamounts were created by hotspots, they are all unique in their size, shape, and volcanic features. The seamounts teem with deep-sea corals, sponges, and fish. Recent expeditions to these seamounts using manned submersibles and ROVs (remotely operated vehicles) have discovered many marine species and have greatly expanded our knowledge of the range of deep-sea corals in this region.



Exploration and Research
Oceanographic and Bathymetric Features


Exploring Alaska’s Seamounts
Seamounts in the Gulf of Alaska
Gulf of Alaska Seamount Expedition
Islands of Life Bloom in the Deep Sea


Fly Around Patton Seamount (28 MB)




Bamboo coral polyp. Photo:NOAA

The Patton Seamount Chain is part of the Gulf of Alaska Seamounts. Click to enlarge.

Deep sea coral in the Gulf of Alaska . Photo: NOAA