Horizon Guyot

Horizon Guyot is a flat-topped submarine mountain, or guyot, in the central Pacific Ocean. Its level summit was shaped by erosion or wave action when the volcanic island stood closer to sea level before subsiding.

Guyots commonly have flat summits because volcanic islands can be eroded near the ocean surface and later sink as the seafloor moves or cools. The flat top is therefore evidence of a former shallow-water stage.

It was named after the research vessel Horizon, whose mid-twentieth-century expeditions surveyed parts of the Pacific seafloor. The name links the feature to oceanographic mapping work rather than to a person.

It is located in the central Pacific Ocean. As a submarine mountain, it lies below sea level and is studied through bathymetric surveys and oceanographic research rather than ordinary land-based maps.