Showing posts with label Allison Guyot. Show all posts
Showing posts with label Allison Guyot. Show all posts

Friday, 12 April 2019

Wikipedia article of the day for April 12, 2019

The Wikipedia article of the day for April 12, 2019 is Allison Guyot.
Allison Guyot is an undersea volcanic mountain with a flat top in the Mid-Pacific Mountains. West of Hawaii and northeast of the Marshall Islands, it rises 1,500 metres (4,900 ft) above the seafloor to a platform 35 by 70 kilometres (22 mi × 43 mi) wide. It was probably formed by a hotspot before plate tectonics moved it north to its present-day location. Radiometric dating puts the formation of a volcanic island at around 111 to 85 million years ago. The island was eventually buried, forming an atoll-like structure and a carbonate platform. The platform emerged above sea level at some time in the Albian or Turonian ages before eventually drowning about 99 million years ago for unknown reasons; it is possible that the emergence damaged its reefs. After a hiatus lasting until the Paleocene, pelagic sedimentation deposited limestone, ooze and sand, which bear traces of climatic events and ocean currents.