Horizon Guyot

Horizon Guyot
Main Line Islands, NOAA bathymetric map with lineations (Horizon Guyot).jpg
Coordinates19°07.9′N 169°27.6′W / 19°07.9′N 169°27.6′W / 19.1317; -169.4600[1]
Horizon is located in North Pacific
Location in the North Pacific Ocean

Horizon Guyot is a presumably Cretaceous guyot (tablemount) in the Mid-Pacific Mountains, Pacific Ocean. It is an elongated ridge, over 300 kilometres (190 mi) long and 4.3 kilometres (2.7 mi) high, that stretches in a northeast-southwest direction and has two flat tops; it rises to a minimum depth of 1,443 metres (4,730 ft). The Mid-Pacific Mountains lie west of Hawaii and northeast of the Line Islands.

It was probably formed by a hotspot, but the evidence is conflicting. Volcanic activity occurred during the Turonian-Cenomanian eras 100.5–89.8 million years ago and another stage has been dated to have occurred 88–82 million years ago. Between these volcanic episodes, carbonate deposition from lagoonal and reefal environments set in and formed limestone. Volcanic islands developed on Horizon Guyot as well and were colonised by plants.

Horizon Guyot became a seamount during the Coniacian-Campanian period. Since then, pelagic ooze has accumulated on the seamount, forming a thick layer that is further modified by ocean currents and by various organisms that live on the seamount; sediments also underwent landsliding. Ferromanganese crusts were deposited on exposed rocks.

Name and research history

The seamount is named after the research vessel RV Horizon[2] and is also known as Horizon Ridge,[3] Horizon Tablemount, Gora Khorayzn and Гора Хорайзн.[4] During the Deep Sea Drilling Project, the drill cores called Site 44 and Site 171 were taken on Horizon Guyot in 1969 and 1971, respectively;[5][6] a further drill core was obtained north of the seamount at Site 313[7] in 1973.[8] This seamount is the best studied seamount of the Mid-Pacific Mountains[9] and more is known about its morphology than any other seamount of the Mid-Pacific Mountains.[10]

Other Languages
français: Guyot Horizon