Guide Seamount
Encyclopedia
Guide Seamount is a seamount
in the eastern Pacific Ocean
, about 16.6±0.5 million years old. It is similar in shape and orientation to the nearby Davidson
, Pioneer
, Rodriguez
, and Gumdrop
seamounts. It is named for the U.S. National Geodetic Survey
survey ship the US&GS Guide
.
Guide Seamount is constructed of four nearly parallel volcanic ridges, separated by sediment-filled throughs. These are aligned parallel to magnetic anomalies in the underlying oceanic crust
. It is very similar in shape and structure to the nearby Davidson Seamount
, except that it is smaller, at approximately 16.5 km (10 mi) by 5 km (3 mi). It rises about 1440 m (4,724 ft) above the seafloor and sits at depth of 1682 m (5,518 ft).
The lavas from Guide are mostly alkalic basalt
, hawaiite
, mugearite
with some pyroclastic flow
s near the top of the summit.
Seamount
A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface , and thus is not an island. These are typically formed from extinct volcanoes, that rise abruptly and are usually found rising from a seafloor of depth. They are defined by oceanographers as...
in the eastern Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, about 16.6±0.5 million years old. It is similar in shape and orientation to the nearby Davidson
Davidson Seamount
Davidson Seamount is a seamount located off the coast of Central California, southwest of Monterey and west of San Simeon. At long and wide, it is one of the largest known seamounts in the world. From base to crest, the seamount is tall, yet its summit is still below the sea surface...
, Pioneer
Pioneer Seamount
Pioneer Seamount is an undersea mountain, or seamount, in the Pacific Ocean off the coast of central California.-Location:Pioneer Seamount is located at 37° 21.1' North Latitude, 123° 26.1' West Longitude, at the base of the continental slope of North America about 95 kilometers off the coast just...
, Rodriguez
Rodriguez Seamount
Rodriguez Seamount is a seamount and guyot located about off the coast of Central California. It is structurally similar to the nearby Guide, Pioneer, Gumdrop, and Davidson seamounts, all located roughly between 37.5° and 34.0° degrees of latitude. This group of seamounts is morphologically...
, and Gumdrop
Gumdrop Seamount
Gumdrop Seamount is a small seamount located on the flank of Pioneer Seamount, off the coast of Central California. It is the northern-most of the related seamounts in the region, which includes Davidson, Guide, Pioneer, and Rodriguez seamounts...
seamounts. It is named for the U.S. National Geodetic Survey
U.S. National Geodetic Survey
National Geodetic Survey, formerly called the U.S. Coast and Geodetic Survey , is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping and charting; and a large number of applications of science...
survey ship the US&GS Guide
USC&GS Guide (1918)
The first USC&GS Guide was a survey ship that served in the United States Coast and Geodetic Survey from 1923 to 1941.-Construction and United States Navy service:...
.
Guide Seamount is constructed of four nearly parallel volcanic ridges, separated by sediment-filled throughs. These are aligned parallel to magnetic anomalies in the underlying oceanic crust
Oceanic crust
Oceanic crust is the part of Earth's lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium...
. It is very similar in shape and structure to the nearby Davidson Seamount
Davidson Seamount
Davidson Seamount is a seamount located off the coast of Central California, southwest of Monterey and west of San Simeon. At long and wide, it is one of the largest known seamounts in the world. From base to crest, the seamount is tall, yet its summit is still below the sea surface...
, except that it is smaller, at approximately 16.5 km (10 mi) by 5 km (3 mi). It rises about 1440 m (4,724 ft) above the seafloor and sits at depth of 1682 m (5,518 ft).
The lavas from Guide are mostly alkalic basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
, hawaiite
Hawaiite
Hawaiite is an olivine basalt with intermediate composition between alkali olivine and mugearite. It was first described at the island of Hawaii. In gemology, hawaiite is a colloquial term for Hawaii-originated peridot,which is gem-quality olivine mineral....
, mugearite
Mugearite
Mugearite is a type of orthoclase-bearing basalt, comprising olivine, apatite, and opaque oxides. The main feldspar in mugearite is oligoclase....
with some pyroclastic flow
Pyroclastic flow
A pyroclastic flow is a fast-moving current of superheated gas and rock , which reaches speeds moving away from a volcano of up to 700 km/h . The flows normally hug the ground and travel downhill, or spread laterally under gravity...
s near the top of the summit.