Wikipedia:Today's featured article/December 10, 2019

Bathymetry map

Limalok is a guyot, an undersea volcanic mountain with a flat top, in the southeastern Marshall Islands in the Pacific Ocean. Located at a depth of 1,255 metres (4,117 ft) with a 636-square-kilometre (246 sq mi) summit platform, it is joined to Mili Atoll and Knox Atoll through a volcanic ridge. Limalok probably started as a shield volcano built up from basaltic rocks; the Macdonald, Rarotonga, Rurutu and Society hotspots may have been involved in its formation. A period of erosion and flattening began around 56 million years ago. During the Paleocene and Eocene, a carbonate platform (mostly red algae) supported an atoll, or an atoll-like structure with reefs. The platform sank below sea level roughly 46–50 million years ago during the Eocene, perhaps because the equatorial area it moved through was too hot or nutrient-rich to support the growth of a coral reef. Thermal subsidence lowered the drowned seamount to its present depth. (Full article...)