Detroit Seamount
Encyclopedia
Detroit Seamount, which was formed around 76 million years ago, is one of the oldest seamount
s of the Hawaiian-Emperor seamount chain
(Meiji Seamount
is the oldest, at 82 million years). It lies near the northernmost end of the chain and is south of Aleutian Islands (near Russia
), at 51°28.80′N 167°36′E It is one of the few seamounts to break the naming scheme of the Emperor seamounts
, which are named mostly after emperors or empresses of the Kofun period
of Japanese history. It is a seamount in the chain, located north of the hinge of the "V" in the image at right.
The Detroit Seamount is as big as the island of Hawaii
.
program of the USGS, and in far more detail in 2001 by leg 197 of the Ocean Drilling Program
(ODP). 2001 marked a two-month excursion aboard the research vessel JOIDES Resolution to collect samples of lava flows from four submerged volcanoes, among them Detroit Seamount (which was drilled twice). The expedition was funded by the Ocean Drilling Program, an international research effort designed to study the world's seafloors, and the drill sites were numbers 1203 through 1206. The project drilled Detroit, Nintoku
, and Koko seamount
s, all in the far northwest of the chain. Detroit seamount was drilled twice (numbered 1203 and 1204), on the summit and on one its secondary cones; care was taken to put the locations away from major fault lines or other geological features that would otherwise invalidate or bias the results.
In 2005 it underwent a detailed geological analysis by scientists from Stanford University.
. The 2005 analysis found that the volcano had been active through much of the Eocene epoch
of geological history (circa 52-34 million years ago), and that activity may have extended into the Oligocine epoch
(under 34 million years ago). The large difference between the youngest and oldest lavas provides evidence that the Hawaii hotspot
migrated far more slowly then it does today; for example, Kohala volcano
(the oldest volcano in of Hawaii island
) first emerged from the sea 500,000 years ago, and last erupted 120,000 years ago, a period of only 380,000 years in comparison to Detroit's 18 million or more years of volcanic activity. The large age difference (51 vs. 34 million years) between the submarine presheid stages and the post-shield rejuvenated stage seems to indicate that volcanoes in the chain can erupt again long after they are believed to be extinct. The volcano is known to have erupted intermediately in an underwater and shallow-water environment.
Detroit seamount has a wide (100,000 square kilometers) base and rises from the bottom of the abyssal plain
to a depth of approximately 1550 m (5,085 ft); in fact, it is as wide as Hawaii island
at the head of the chain. The width of the seamount, as well as the extremely gentle slope, which is very shallow even for a Hawaiian shield volcano
, seem to show that the seamount suffered a catastophic collapse sometime in its history; such a collapse is a relatively common event in the growth of Hawaiian volcanoes, caused when the volcanoes grow so fast that they destabilize. A sequence of sediments 800 m (2,624.7 ft) to 900 m (2,952.8 ft) thick compose the volcano, in several layers. Some papers refer to only the shallowest part of the volcano as Detroit Seamount, and the rest of the seamount as the "Detroit Rise." The tallest volcanic cones of the seamount peak 1 km (0.621372736649807 mi) to 2 km (1.2 mi) above the rest of the seamount.
, which was also in that direction. The drift is of Oligocene
to Quaternary
-era mud, deposited by ocean current
s. The tallest parts of the seamount protrude above this "mud cap," which at its deepest is estimated to be 840 m (2,756 ft) thick. They formed 34 million years ago.
A 2005 analysis of the results of the 2001 JOIDES Resolution excursion found the age, composition, structure, and history of growth for the seamount. The evaluation also focused on the strange cones that poked through the sedimentary layers. They were deposited onto the seamount before the Meiji Drift developed. Analysis put the latest date of their formation at 60 million years ago, 6 million years into the seamount's life.
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...
s of the Hawaiian-Emperor seamount chain
Hawaiian-Emperor seamount chain
The Hawaiian–Emperor seamount chain is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Seamounts, a vast underwater mountain region of islands and intervening seamounts, atolls, shallows, banks and reefs along a line trending...
(Meiji Seamount
Meiji Seamount
Meiji Seamount is the oldest seamount in the Hawaiian-Emperor seamount chain, with an estimated age of 82 million years. It lies at the northernmost end of the chain, and is perched at the outer slope of the Kuril-Kamchatka Trench...
is the oldest, at 82 million years). It lies near the northernmost end of the chain and is south of Aleutian Islands (near Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
), at 51°28.80′N 167°36′E It is one of the few seamounts to break the naming scheme of the Emperor seamounts
Hawaiian-Emperor seamount chain
The Hawaiian–Emperor seamount chain is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, and the Emperor Seamounts, a vast underwater mountain region of islands and intervening seamounts, atolls, shallows, banks and reefs along a line trending...
, which are named mostly after emperors or empresses of the Kofun period
Kofun period
The is an era in the history of Japan from around 250 to 538. It follows the Yayoi period. The word kofun is Japanese for the type of burial mounds dating from this era. The Kofun and the subsequent Asuka periods are sometimes referred to collectively as the Yamato period...
of Japanese history. It is a seamount in the chain, located north of the hinge of the "V" in the image at right.
The Detroit Seamount is as big as the island of Hawaii
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
.
Mapping
The seamount was initially mapped by the GLORIAGloria
-In Christian liturgy and music:*Gloria in Excelsis Deo, the main doxology or hymn of the Roman Catholic and Anglican Mass, and also known as the Great Doxology in the Eastern Orthodox Church...
program of the USGS, and in far more detail in 2001 by leg 197 of the Ocean Drilling Program
Ocean Drilling Program
The Ocean Drilling Program was an international cooperative effort to explore and study the composition and structure of the Earth's ocean basins. ODP, which began in 1985, was the direct successor to the highly successful Deep Sea Drilling Project initiated in 1968 by the United States...
(ODP). 2001 marked a two-month excursion aboard the research vessel JOIDES Resolution to collect samples of lava flows from four submerged volcanoes, among them Detroit Seamount (which was drilled twice). The expedition was funded by the Ocean Drilling Program, an international research effort designed to study the world's seafloors, and the drill sites were numbers 1203 through 1206. The project drilled Detroit, Nintoku
Nintoku Seamount
Nintoku Seamount or Nintoku Guyot is a seamount and guyot in the Hawaiian-Emperor seamount chain. It is a large, irregularly shaped volcano that last erupted 65 million years ago. Three lava flows have been sampled at Nintoku Seamount; the flows are almost all alkalic lava...
, and Koko seamount
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...
s, all in the far northwest of the chain. Detroit seamount was drilled twice (numbered 1203 and 1204), on the summit and on one its secondary cones; care was taken to put the locations away from major fault lines or other geological features that would otherwise invalidate or bias the results.
In 2005 it underwent a detailed geological analysis by scientists from Stanford University.
Geology
After it was initially formed 51 million years ago, the volcano was active for 25 million years. Parts of the volcano appear to be older than the oldest volcano in the chain, Meiji SeamountMeiji Seamount
Meiji Seamount is the oldest seamount in the Hawaiian-Emperor seamount chain, with an estimated age of 82 million years. It lies at the northernmost end of the chain, and is perched at the outer slope of the Kuril-Kamchatka Trench...
. The 2005 analysis found that the volcano had been active through much of the Eocene epoch
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
of geological history (circa 52-34 million years ago), and that activity may have extended into the Oligocine epoch
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
(under 34 million years ago). The large difference between the youngest and oldest lavas provides evidence that the Hawaii hotspot
Hawaii hotspot
The Hawaii hotspot is the volcanic hotspot that created the Hawaiian Islands in the central Pacific Ocean, and is one of Earth's best-known and most heavily-studied hotspots....
migrated far more slowly then it does today; for example, Kohala volcano
Kohala (mountain)
Kohala is the oldest of five volcanoes that make up the island of Hawaii. Kohala is an estimated one million years old—so old that it experienced, and recorded, a reversal of magnetic field 780,000 years ago. It is believed to have breached sea level more than 500,000 years ago and to...
(the oldest volcano in of Hawaii island
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
) first emerged from the sea 500,000 years ago, and last erupted 120,000 years ago, a period of only 380,000 years in comparison to Detroit's 18 million or more years of volcanic activity. The large age difference (51 vs. 34 million years) between the submarine presheid stages and the post-shield rejuvenated stage seems to indicate that volcanoes in the chain can erupt again long after they are believed to be extinct. The volcano is known to have erupted intermediately in an underwater and shallow-water environment.
Detroit seamount has a wide (100,000 square kilometers) base and rises from the bottom of the abyssal plain
Abyssal plain
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 metres. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. They are among the flattest, smoothest...
to a depth of approximately 1550 m (5,085 ft); in fact, it is as wide as Hawaii island
Hawaii (island)
The Island of Hawaii, also called the Big Island or Hawaii Island , is a volcanic island in the North Pacific Ocean...
at the head of the chain. The width of the seamount, as well as the extremely gentle slope, which is very shallow even for a Hawaiian shield volcano
Shield volcano
A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their large size and low profile, resembling a warrior's shield. This is caused by the highly fluid lava they erupt, which travels farther than lava erupted from more explosive volcanoes...
, seem to show that the seamount suffered a catastophic collapse sometime in its history; such a collapse is a relatively common event in the growth of Hawaiian volcanoes, caused when the volcanoes grow so fast that they destabilize. A sequence of sediments 800 m (2,624.7 ft) to 900 m (2,952.8 ft) thick compose the volcano, in several layers. Some papers refer to only the shallowest part of the volcano as Detroit Seamount, and the rest of the seamount as the "Detroit Rise." The tallest volcanic cones of the seamount peak 1 km (0.621372736649807 mi) to 2 km (1.2 mi) above the rest of the seamount.
Mantle of sediment
The seamount was thought to be covered in a cap of sediment, which was confirmed in 2005. All but the topmost cones of Detroit seamount are capped in a thick layer of sediments, which were found to have drifted there from a direction due northwest. The drift that carried the sediments onto the volcano was named the "Meiji Drift," after the oldest volcano in the chain, Meiji SeamountMeiji Seamount
Meiji Seamount is the oldest seamount in the Hawaiian-Emperor seamount chain, with an estimated age of 82 million years. It lies at the northernmost end of the chain, and is perched at the outer slope of the Kuril-Kamchatka Trench...
, which was also in that direction. The drift is of Oligocene
Oligocene
The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...
to Quaternary
Quaternary
The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...
-era mud, deposited by ocean current
Ocean current
An ocean current is a continuous, directed movement of ocean water generated by the forces acting upon this mean flow, such as breaking waves, wind, Coriolis effect, cabbeling, temperature and salinity differences and tides caused by the gravitational pull of the Moon and the Sun...
s. The tallest parts of the seamount protrude above this "mud cap," which at its deepest is estimated to be 840 m (2,756 ft) thick. They formed 34 million years ago.
A 2005 analysis of the results of the 2001 JOIDES Resolution excursion found the age, composition, structure, and history of growth for the seamount. The evaluation also focused on the strange cones that poked through the sedimentary layers. They were deposited onto the seamount before the Meiji Drift developed. Analysis put the latest date of their formation at 60 million years ago, 6 million years into the seamount's life.