Bowie Seamount
Encyclopedia
Bowie Seamount is a large submarine volcano
in the northeastern Pacific Ocean
, located 180 km (111.8 mi) west of Haida Gwaii, British Columbia
, Canada
.
The seamount is named after William Bowie
of the Coast & Geodetic Survey.
The volcano has a flat-topped summit (thus making it a guyot
) rising about 3000 m (9,842.5 ft) above the seabed
, to 24 m (79 ft) below sea level
. The seamount lies at the southern end of a long underwater volcanic mountain range
called the Pratt-Welker or Kodiak-Bowie Seamount chain
, stretching from the Aleutian Trench
in the north almost to the Queen Charlotte Islands in the south.
Bowie Seamount lies on the Pacific Plate
, a large segment of the Earth's surface which moves in a northwestern direction under the Pacific Ocean. Its northern and eastern flanks are surrounded by neighboring submarine volcanoes; Hodgkins Seamount
on its northern flank and Graham Seamount
on its eastern flank.
s are volcanic mountains which rise from the seafloor. The unlimited supply of water surrounding these volcanoes can cause them to behave differently from volcanoes on land. The lava emitted in eruptions at Bowie Seamount is made of basalt
, a common gray to black or dark brown volcanic rock
low in silica content (the lava is mafic
). When basaltic lava makes contact with the cold sea water, it may cool very rapidly to form pillow lava
, through which the hot lava breaks to form another pillow. Pillow lava is typically fine-grained, due to rapid cooling, with a glassy crust, and has radial jointing.
With a height of at least 3000 m (9,842.5 ft) and rising to within only 24 m (79 ft) of the sea surface, Bowie Seamount is the shallowest submarine volcano on the British Columbia Coast
, as well as in Canadian waters, and one of the shallowest submarine volcanoes in the northeast Pacific Ocean. Most seamounts are found hundreds to thousands of meters below sea level, and are therefore considered to be within the deep sea
. In contrast, if Bowie Seamount were on land it would be about 600 m (1,968.5 ft) higher than Whistler Mountain
in southwestern British Columbia and 800 m (2,624.7 ft) lower than Mount Robson
, the highest mountain in the Canadian portion of the Rocky Mountains
.
Bowie Seamount is about 55 km (34 mi) long and 24 km (15 mi) wide. Its flat-topped summit is made of weakly consolidated tephra
and consists of two terraces. The lowest terrace is about 230 m (754.6 ft) below sea level while the highest is about 80 m (262.5 ft) below sea level, but contains steep-sided secondary summits that rise to within 25 m (82 ft) below sea level. From a physical perspective, the effective size of the submarine volcano is possibly a lot greater than its mass alone would suggest. The effects of other submarine volcanoes along the Pacific Northwest
, including Cobb Seamount
off the coast of Washington, can be noticed in the composition and abundance of the tiny floating organisms called plankton
up to 30 km (18.6 mi) away from the seamount summit. Because of its similar size, Bowie Seamount most likely has a similar effect on its adjacent waters.
Bowie Seamount was formed by submarine eruptions along fissures
in the seabed throughout the last glacial, or "Wisconsinian", period, which began about 110,000 years ago and ended between 10,000 and 15,000 years ago. While most submarine volcanoes in the Pacific Ocean are more than one million years old, Bowie Seamount is relatively quite young. Its base was formed less than one million years ago but its summit shows evidence of volcanic activity as recently as 18,000 years ago. This is very recent in geological terms, suggesting the volcano may yet have some ongoing volcanic activity.
Close to Bowie's submerged summit, former coastlines cut by wave actions and beach deposits show that the submarine volcano would once have stood above sea level, as either a single volcanic island or as a small cluster of shoals that would have been volcanically active. Sea levels during the last glacial period, when Bowie Seamount was formed, were at least 100 m (328.1 ft) lower than they are today.
may have formed above a center of upwelling magma called a mantle plume
. The seamounts comprising the Kodiak-Bowie Seamount chain would be formed above the mantle plume and carried away from the mantle plume's magmatic source as the Pacific Plate
moves in a northwesterly direction towards the Aleutian Trench
, along the southern coastline of Alaska
.
The volcanic rocks which make up some of the seamounts in the Kodiak-Bowie Seamount chain are unusual in that they have an acid-neutralizing chemical substance like typical ocean-island basalts but a low percentage of strontium
as found at mid-ocean ridge
basalts. However, the strontium-bearing volcanic rocks comprising Bowie Seamount also contain lead
. Therefore, the magma mixtures that formed Bowie Seamount seem to have originated from varying degrees of partial melting
of a depleted source in the Earth's mantle
and basalts which had distinctly high lead isotopic ratios. Estimates during geological studies indicate that the abundance of the depleted-source component ranges from 60 to 80 percent.
Some aspects of the origin of the Kodiak-Bowie Seamount chain remain uncertain. The volcanic rocks found at the Tuzo Wilson Seamounts
south of Bowie are fresh glassy pillow basalts of recent age, as would be expected if these seamounts are located above or close to a mantle plume south of the Queen Charlotte Islands. However, the origin of Bowie Seamount is less certain because even though the seafloor which Bowie lies on formed 16 million years ago during the late Miocene
period, Bowie's summit shows evidence of recent volcanic activity. If Bowie Seamount formed above a mantle plume at the site presently occupied by the Tuzo Wilson Seamounts, it has been displaced from its magma source by about 625 km (388.4 mi) at a rate of about 4 cm (2 in) per year. The geologic history of Bowie Seamount is consistent with its flat-topped eroded summit, but the source for Bowie's recent volcanic activity remains uncertain. Still others, such as Dickens Seamount and Pratt Seamount further north of Bowie Seamount, fall a little to the side of the chain's expected trend. Another hypothesized origin of some or all seamounts in the Kodiak-Bowie Seamount chain is that they formed on top of the Explorer Ridge
, a divergent tectonic plate
boundary west of Vancouver Island
, and have been displaced from it by seafloor spreading
.
Although some of the seamounts in the Kodiak-Bowie Seamount chain appear to follow the expected age progression for a mantle plume trail, others, such as Denson Seamount
, are older than that hypothesis would suggest. As a result, the Kodiak-Bowie Seamount chain has also been proposed by geoscientists to be a mix of ridge and mantle plume volcanism.
Bowie Seamount supports a biologically rich area with a vigorous ecosystem. Studies have recorded high densities of crab
, sea star
s, sea anemone
s, sponges, squid
, octopus
, rockfish
, halibut
and sablefish
. Eight species of marine mammal
have been found in the Bowie Seamount area, including Steller Sea Lions, Orca
, humpback
and sperm whale
s, along with 16 varieties of seabird
s. This has made Bowie Seamount a rare habitat in the northeast Pacific Ocean and one of the most biologically rich submarine volcanoes on Earth. The rich marine life is due to the intense food supply of microscopic animals and plants, including phytoplankton
and zooplankton
.
and Guujaaw
, President of the Council of the Haida Nation
, at a community celebration held at the Kaay Llnagaay Haida Heritage Centre in Skidegate on the Queen Charlotte Islands
, also called Haida Gwaii. During the announcement, Natural Resources Minister Gary Lunn
said: "Bowie Seamount is an oceanic oasis in the deep sea, a rare and ecologically rich marine area, and our government is proud to take action to ensure it is protected. By working in partnership with the Council of the Haida Nation and groups like the World Wildlife Fund-Canada, we are ensuring this unique treasure is preserved for future generations." Since its formation, it measures about 118 km (73 mi) long and 80 km (50 mi) wide, totaling an area of 6131 km³ (1,471 cu mi). This is the northernmost of the two Marine Protected Areas on the British Columbia Coast; the southermost is the Endeavour Hydrothermal Vents
, an active hydrothermal vent
zone of the Juan de Fuca Ridge
250 km (155.3 mi) southwest of Vancouver Island. The Bowie Seamount Marine Protected Area also includes Peirce Seamount
(also called Davidson Seamount) and Hodgkins Seamount
.
equipment. In March 1969, dives were made at the submarine volcano by Canadian Forces Maritime Command
divers from the CSS Parizeau during a new study for device package placement. Two dives were made to the summit where monochrome photographs
were taken to establish the environment of Bowie's base and some biological tests were gathered to detect possible harmful organisms, including plants, animals, or bacteria. These specimens were identified at the Pacific Biological Station in Nanaimo, creating a list of eleven varieties of sea bottom invertebrates.
In August 1969, Canadian Forces Maritime Command divers made more dives during scientific studies by the Fisheries Research Board of Canada. They recognized the existence of very thick groups of rockfish
floating on top of Bowie's flat-topped summit and a variety of bottom life. A number of monochrome photographs were taken and a few seaweed
s were gathered for documents, but no species record was created for other types of oceanic life around Bowie Seamount.
In November 1996, a release of the National Geographic Magazine
comprised a piece of writing titled "Realm of the Seamount", illustrating dives made at Bowie Seamount by two diving explorers named Bill Curtsinger and Eric Hiner. They explored Bowie Seamount down to depths of 50 m (164 ft) using scuba diving equipment while the slopes of the seamount down to 150 m (492.1 ft). Images photographed by the two diving explorers featured one of Bowie's rugged peaks covered with thick seaweeds and multicoloured sea bottom invertebrates. Thick groups of young rockfish were detected on Bowie's steep flanks.
Scientist Bill Austin of Khoyatan Marine Lab in the Northeast Pacific looked over a video film earned throughout the National Geographic dives to verify the flora
and fauna
of the sea bottom surrounding Bowie Seamount. From the video film, Austin recognized some of the most noticeable invertebrates and noted that a few species more regularly occurring between high-tide and low-tide
marks and shallow environments were found deeper than might normally be expected, and were bigger than normal.
A team of five divers visited the seamount August 3–5, 2003 and conducted a biological and photographic survey of the summit down to depths of about 40 m (131.2 ft). A total of 18 taxa of algae, 83 taxa of conspicuous invertebrates and 12 taxa of fishes were documented, approximately 180 underwater still photographs were taken and approximately 90 minutes of digital video were recorded. Of particular note were the dense schools of rockfish hovering over the summit and numerous curious prowfish.
who played a key role to establish the Bowie Seamount Marine Protected Area, the submarine volcano is called Sgaan Kinghlas. In their language it means "Supernatural Being Looking Outward".
This seamount has long been recognized by the Haida Nation as a special place. Guujaaw
, President of the Council of the Haida Nation, has said: "Sgaan Kinghlas represents a shift in recognizing the need for respect and care for the Earth. This is a very significant turning point in reversing the trends that have been leading to the depletion of life in the sea."
during winter. Waves have been recorded with heights of more than 20 m (65.6 ft), enough to expose the summit and cause devastation to any vessel transitting the area. For this reason, Bowie Seamount is recognized as a hazard to navigation and is avoided by shipping vessels.
Submarine volcano
Submarine volcanoes are underwater fissures in the Earth's surface from which magma can erupt. They are estimated to account for 75% of annual magma output. The vast majority are located near areas of tectonic plate movement, known as ocean ridges...
in the northeastern 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...
, located 180 km (111.8 mi) west of Haida Gwaii, British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
.
The seamount is named after William Bowie
William Bowie
William Bowie, B.S., C.E., M.A. was an American geodetic engineer.-Background and education:He was born at Grassland, an historic estate near Annapolis Junction, Anne Arundel County, Maryland, to Thomas John Bowie and Susanna Anderson. He was educated in public schools, at St...
of the Coast & Geodetic Survey.
The volcano has a flat-topped summit (thus making it a guyot
Guyot
A guyot , also known as a tablemount, is an isolated underwater volcanic mountain , with a flat top over 200 meters below the surface of the sea. The diameters of these flat summits can exceed ....
) rising about 3000 m (9,842.5 ft) above the seabed
Seabed
The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...
, to 24 m (79 ft) below sea level
Sea level
Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...
. The seamount lies at the southern end of a long underwater volcanic mountain range
Mountain range
A mountain range is a single, large mass consisting of a succession of mountains or narrowly spaced mountain ridges, with or without peaks, closely related in position, direction, formation, and age; a component part of a mountain system or of a mountain chain...
called the Pratt-Welker or Kodiak-Bowie Seamount chain
Kodiak-Bowie Seamount chain
The Kodiak–Bowie Seamount chain, also called the Pratt–Welker Seamount chain, is a seamount chain in southeastern Gulf of Alaska stretching from the Aleutian Trench in the north to Bowie Seamount, the youngest volcano in the chain, which lies west of the Queen Charlotte Islands,...
, stretching from the Aleutian Trench
Aleutian Trench
The Aleutian Trench is a subduction zone and oceanic trench which runs along the southern coastline of Alaska and the adjacent waters of northeastern Siberia off the coast of Kamchatka Peninsula. It is classified as a "marginal trench" in the east as it runs along the margin of the continent, and...
in the north almost to the Queen Charlotte Islands in the south.
Bowie Seamount lies on the Pacific Plate
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate....
, a large segment of the Earth's surface which moves in a northwestern direction under the Pacific Ocean. Its northern and eastern flanks are surrounded by neighboring submarine volcanoes; Hodgkins Seamount
Hodgkins Seamount
Hodgkins Seamount is a seamount in the Kodiak-Bowie Seamount chain, located south of Pierce Seamount and north of Bowie Seamount. Hodgkins Seamount has apparently experienced two generically different episodes of volcanism, separated by about 12 million years ago...
on its northern flank and Graham Seamount
Graham Seamount
The Graham Seamount is a seamount located in the Pacific Ocean off the coast of the Queen Charlotte Islands, British Columbia, Canada.-References:*-See also:*Volcanism of Canada*Volcanism of Western Canada*List of volcanoes in Canada...
on its eastern flank.
Structure
SeamountSeamount
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 are volcanic mountains which rise from the seafloor. The unlimited supply of water surrounding these volcanoes can cause them to behave differently from volcanoes on land. The lava emitted in eruptions at Bowie Seamount is made of 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...
, a common gray to black or dark brown volcanic rock
Volcanic rock
Volcanic rock is a rock formed from magma erupted from a volcano. In other words, it is an igneous rock of volcanic origin...
low in silica content (the lava is mafic
Mafic
Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron; the term is a portmanteau of the words "magnesium" and "ferric". Most mafic minerals are dark in color and the relative density is greater than 3. Common rock-forming mafic minerals include olivine,...
). When basaltic lava makes contact with the cold sea water, it may cool very rapidly to form pillow lava
Pillow lava
Pillow lavas are lavas that contain characteristic pillow-shaped structures that are attributed to the extrusion of the lava under water, or subaqueous extrusion. Pillow lavas in volcanic rock are characterized by thick sequences of discontinuous pillow-shaped masses, commonly up to one metre in...
, through which the hot lava breaks to form another pillow. Pillow lava is typically fine-grained, due to rapid cooling, with a glassy crust, and has radial jointing.
With a height of at least 3000 m (9,842.5 ft) and rising to within only 24 m (79 ft) of the sea surface, Bowie Seamount is the shallowest submarine volcano on the British Columbia Coast
British Columbia Coast
The British Columbia Coast or BC Coast is Canada's western continental coastline on the Pacific Ocean. The usage is synonymous with the term West Coast of Canada....
, as well as in Canadian waters, and one of the shallowest submarine volcanoes in the northeast Pacific Ocean. Most seamounts are found hundreds to thousands of meters below sea level, and are therefore considered to be within the deep sea
Deep sea
The deep sea, or deep layer, is the lowest layer in the ocean, existing below the thermocline and above the seabed, at a depth of 1000 fathoms or more. Little or no light penetrates this part of the ocean and most of the organisms that live there rely for subsistence on falling organic matter...
. In contrast, if Bowie Seamount were on land it would be about 600 m (1,968.5 ft) higher than Whistler Mountain
Whistler Mountain
Whistler Mountain is a mountain in the Fitzsimmons Range of the Pacific Ranges of the Coast Mountains, located on the northwestern edge of Garibaldi Provincial Park. It is the location of the Whistler-Blackcomb ski resort and the town of Whistler, British Columbia.The original name of the mountain...
in southwestern British Columbia and 800 m (2,624.7 ft) lower than Mount Robson
Mount Robson
Mount Robson is the most prominent mountain in North America's Rocky Mountain range; it is also the highest point in the Canadian Rockies. The mountain is located entirely within Mount Robson Provincial Park of British Columbia, and is part of the Rainbow Range. It is commonly thought to be the...
, the highest mountain in the Canadian portion of the Rocky Mountains
Canadian Rockies
The Canadian Rockies comprise the Canadian segment of the North American Rocky Mountains range. They are the eastern part of the Canadian Cordillera, extending from the Interior Plains of Alberta to the Rocky Mountain Trench of British Columbia. The southern end borders Idaho and Montana of the USA...
.
Bowie Seamount is about 55 km (34 mi) long and 24 km (15 mi) wide. Its flat-topped summit is made of weakly consolidated tephra
Tephra
200px|thumb|right|Tephra horizons in south-central [[Iceland]]. The thick and light coloured layer at center of the photo is [[rhyolitic]] tephra from [[Hekla]]....
and consists of two terraces. The lowest terrace is about 230 m (754.6 ft) below sea level while the highest is about 80 m (262.5 ft) below sea level, but contains steep-sided secondary summits that rise to within 25 m (82 ft) below sea level. From a physical perspective, the effective size of the submarine volcano is possibly a lot greater than its mass alone would suggest. The effects of other submarine volcanoes along the Pacific Northwest
Pacific Northwest
The Pacific Northwest is a region in northwestern North America, bounded by the Pacific Ocean to the west and, loosely, by the Rocky Mountains on the east. Definitions of the region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners. A common concept of the...
, including Cobb Seamount
Cobb Seamount
Cobb Seamount is a seamount and guyot located west of Gray's Harbor, Washington, United States. Cobb Seamount is one of the seamounts in the Cobb-Eickelberg Seamount chain, a chain of underwater volcanoes created by the Cobb hotspot that terminates near the coast of Alaska. It is aligned along...
off the coast of Washington, can be noticed in the composition and abundance of the tiny floating organisms called plankton
Plankton
Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...
up to 30 km (18.6 mi) away from the seamount summit. Because of its similar size, Bowie Seamount most likely has a similar effect on its adjacent waters.
Eruptive history
Fissure vent
A fissure vent, also known as a volcanic fissure or simply fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is usually a few meters wide and may be many kilometers long. Fissure vents can cause large flood basalts and lava channels...
in the seabed throughout the last glacial, or "Wisconsinian", period, which began about 110,000 years ago and ended between 10,000 and 15,000 years ago. While most submarine volcanoes in the Pacific Ocean are more than one million years old, Bowie Seamount is relatively quite young. Its base was formed less than one million years ago but its summit shows evidence of volcanic activity as recently as 18,000 years ago. This is very recent in geological terms, suggesting the volcano may yet have some ongoing volcanic activity.
Close to Bowie's submerged summit, former coastlines cut by wave actions and beach deposits show that the submarine volcano would once have stood above sea level, as either a single volcanic island or as a small cluster of shoals that would have been volcanically active. Sea levels during the last glacial period, when Bowie Seamount was formed, were at least 100 m (328.1 ft) lower than they are today.
Origins
The origin of the volcanism that produced Bowie Seamount is not without controversy. Geological studies indicate that the Kodiak-Bowie Seamount chainKodiak-Bowie Seamount chain
The Kodiak–Bowie Seamount chain, also called the Pratt–Welker Seamount chain, is a seamount chain in southeastern Gulf of Alaska stretching from the Aleutian Trench in the north to Bowie Seamount, the youngest volcano in the chain, which lies west of the Queen Charlotte Islands,...
may have formed above a center of upwelling magma called a mantle plume
Mantle plume
A mantle plume is a hypothetical thermal diapir of abnormally hot rock that nucleates at the core-mantle boundary and rises through the Earth's mantle. Such plumes were invoked in 1971 to explain volcanic regions that were not thought to be explicable by the then-new theory of plate tectonics. Some...
. The seamounts comprising the Kodiak-Bowie Seamount chain would be formed above the mantle plume and carried away from the mantle plume's magmatic source as the Pacific Plate
Pacific Plate
The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres, it is the largest tectonic plate....
moves in a northwesterly direction towards the Aleutian Trench
Aleutian Trench
The Aleutian Trench is a subduction zone and oceanic trench which runs along the southern coastline of Alaska and the adjacent waters of northeastern Siberia off the coast of Kamchatka Peninsula. It is classified as a "marginal trench" in the east as it runs along the margin of the continent, and...
, along the southern coastline of Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
.
The volcanic rocks which make up some of the seamounts in the Kodiak-Bowie Seamount chain are unusual in that they have an acid-neutralizing chemical substance like typical ocean-island basalts but a low percentage of strontium
Strontium
Strontium is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when exposed to air. It occurs naturally in the minerals celestine and...
as found at mid-ocean ridge
Mid-ocean ridge
A mid-ocean ridge is a general term for an underwater mountain system that consists of various mountain ranges , typically having a valley known as a rift running along its spine, formed by plate tectonics. This type of oceanic ridge is characteristic of what is known as an oceanic spreading...
basalts. However, the strontium-bearing volcanic rocks comprising Bowie Seamount also contain lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
. Therefore, the magma mixtures that formed Bowie Seamount seem to have originated from varying degrees of partial melting
Partial melting
Partial melting occurs when only a portion of a solid is melted. For mixed substances, such as a rock containing several different minerals or a mineral that displays solid solution, this melt can be different from the bulk composition of the solid....
of a depleted source in the Earth's mantle
Mantle (geology)
The mantle is a part of a terrestrial planet or other rocky body large enough to have differentiation by density. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core....
and basalts which had distinctly high lead isotopic ratios. Estimates during geological studies indicate that the abundance of the depleted-source component ranges from 60 to 80 percent.
Some aspects of the origin of the Kodiak-Bowie Seamount chain remain uncertain. The volcanic rocks found at the Tuzo Wilson Seamounts
Tuzo Wilson Seamounts
The Tuzo Wilson Seamounts, also called J. Tuzo Wilson Knolls and Tuzo Wilson Knolls, are two young active submarine volcanoes off the coast of British Columbia, Canada, located northwest of Vancouver Island and south of the Queen Charlotte Islands...
south of Bowie are fresh glassy pillow basalts of recent age, as would be expected if these seamounts are located above or close to a mantle plume south of the Queen Charlotte Islands. However, the origin of Bowie Seamount is less certain because even though the seafloor which Bowie lies on formed 16 million years ago during the late Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
period, Bowie's summit shows evidence of recent volcanic activity. If Bowie Seamount formed above a mantle plume at the site presently occupied by the Tuzo Wilson Seamounts, it has been displaced from its magma source by about 625 km (388.4 mi) at a rate of about 4 cm (2 in) per year. The geologic history of Bowie Seamount is consistent with its flat-topped eroded summit, but the source for Bowie's recent volcanic activity remains uncertain. Still others, such as Dickens Seamount and Pratt Seamount further north of Bowie Seamount, fall a little to the side of the chain's expected trend. Another hypothesized origin of some or all seamounts in the Kodiak-Bowie Seamount chain is that they formed on top of the Explorer Ridge
Explorer Ridge
The Explorer Ridge is a mid-ocean ridge, a divergent tectonic plate boundary located about west of Vancouver Island, British Columbia, Canada. It lies at the northern extremity of the Pacific spreading axis...
, a divergent tectonic plate
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
boundary west of Vancouver Island
Vancouver Island
Vancouver Island is a large island in British Columbia, Canada. It is one of several North American locations named after George Vancouver, the British Royal Navy officer who explored the Pacific Northwest coast of North America between 1791 and 1794...
, and have been displaced from it by seafloor spreading
Seafloor spreading
Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics....
.
Although some of the seamounts in the Kodiak-Bowie Seamount chain appear to follow the expected age progression for a mantle plume trail, others, such as Denson Seamount
Denson Seamount
Denson Seamount is a submarine volcano in the Kodiak-Bowie Seamount chain, with an estimated age of 18 million years. It lies at the southern end of the chain near the Canada-United States border. It was one of the underground volcanic extrusions investigated by the 2004 Gulf of Alaska Seamount...
, are older than that hypothesis would suggest. As a result, the Kodiak-Bowie Seamount chain has also been proposed by geoscientists to be a mix of ridge and mantle plume volcanism.
Biology
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
, sea star
Sea star
Starfish or sea stars are echinoderms belonging to the class Asteroidea. The names "starfish" and "sea star" essentially refer to members of the class Asteroidea...
s, sea anemone
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...
s, sponges, squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...
, octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
, rockfish
Rockfish
Rockfish may refer to one of the following fishes:* One of several species in the Sebastes genus of the Sebastidae family, including the Shortraker rockfish, Rougheye rockfish, Blue rockfish, Yellow tail rockfish and many others....
, halibut
Halibut
Halibut is a flatfish, genus Hippoglossus, from the family of the right-eye flounders . Other flatfish are also called halibut. The name is derived from haly and butt , for its popularity on Catholic holy days...
and sablefish
Sablefish
The sablefish, Anoplopoma fimbria, is one of two members of the fish family Anoplopomatidae and the only species in the Anoplopoma genus...
. Eight species of marine mammal
Marine mammal
Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...
have been found in the Bowie Seamount area, including Steller Sea Lions, Orca
Orca
The killer whale , commonly referred to as the orca, and less commonly as the blackfish, is a toothed whale belonging to the oceanic dolphin family. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas...
, humpback
Humpback Whale
The humpback whale is a species of baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the...
and sperm whale
Sperm Whale
The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
s, along with 16 varieties of seabird
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
s. This has made Bowie Seamount a rare habitat in the northeast Pacific Ocean and one of the most biologically rich submarine volcanoes on Earth. The rich marine life is due to the intense food supply of microscopic animals and plants, including phytoplankton
Phytoplankton
Phytoplankton are the autotrophic component of the plankton community. The name comes from the Greek words φυτόν , meaning "plant", and πλαγκτός , meaning "wanderer" or "drifter". Most phytoplankton are too small to be individually seen with the unaided eye...
and zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
.
Bowie Seamount Marine Protected Area
Because of its biological richness, Bowie Seamount was designated as Canada's Seventh Marine Protected Area on April 19, 2008 under the Oceans Act and has been described as an "Oceanic Oasis". The announcement was made by federal Fisheries Minister Loyola HearnLoyola Hearn
Loyola Hearn, PC is the Canadian Ambassador to Ireland. He served as a Member of the Canadian House of Commons from 2000 to 2008, and as Minister of Fisheries and Oceans from February 6, 2006 to October 30, 2008....
and Guujaaw
Guujaaw
Guujaaw is a traditional singer, wood carver, traditional medicine practitioner and political activist. He is a Haida, of the Raven Clan of Skedans.-Background:Beginning in the 1970s, Guujaaw worked to protect Gwaii Haanas from logging activity...
, President of the Council of the Haida Nation
Council of the Haida Nation
The Council of the Haida Nation is the Aboriginal Sovereign Authority and Government of the Haida Nation. The Haida Nation is engaged in a Title dispute of their territories, Haida Gwaii, with the government of Canada. The Haida Nation also includes portions of Alaska...
, at a community celebration held at the Kaay Llnagaay Haida Heritage Centre in Skidegate on the Queen Charlotte Islands
Queen Charlotte Islands
Haida Gwaii , formerly the Queen Charlotte Islands, is an archipelago on the North Coast of British Columbia, Canada. Haida Gwaii consists of two main islands: Graham Island in the north, and Moresby Island in the south, along with approximately 150 smaller islands with a total landmass of...
, also called Haida Gwaii. During the announcement, Natural Resources Minister Gary Lunn
Gary Lunn
Gary Vincent Lunn, PC, MP is the former Canadian Member of Parliament for the British Columbia riding of Saanich—Gulf Islands. He served in the House of Commons from 1997 to 2011, first as a member of the Reform Party of Canada and subsequently as a member of the Canadian Alliance and the...
said: "Bowie Seamount is an oceanic oasis in the deep sea, a rare and ecologically rich marine area, and our government is proud to take action to ensure it is protected. By working in partnership with the Council of the Haida Nation and groups like the World Wildlife Fund-Canada, we are ensuring this unique treasure is preserved for future generations." Since its formation, it measures about 118 km (73 mi) long and 80 km (50 mi) wide, totaling an area of 6131 km³ (1,471 cu mi). This is the northernmost of the two Marine Protected Areas on the British Columbia Coast; the southermost is the Endeavour Hydrothermal Vents
Endeavour Hydrothermal Vents
The Endeavour Hydrothermal Vents are a group of hydrothermal vents in the northeastern Pacific Ocean, located southwest of Vancouver Island, British Columbia, Canada...
, an active hydrothermal vent
Hydrothermal vent
A hydrothermal vent is a fissure in a planet's surface from which geothermally heated water issues. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart, ocean basins, and hotspots. Hydrothermal vents exist because the earth is both...
zone of the Juan de Fuca Ridge
Juan de Fuca Ridge
The Juan de Fuca Ridge is a tectonic spreading center located off the coasts of the state of Washington in the United States and the province of British Columbia in Canada. It runs northward from a transform boundary, the Blanco Fracture Zone, to a triple junction with the Nootka Fault and the...
250 km (155.3 mi) southwest of Vancouver Island. The Bowie Seamount Marine Protected Area also includes Peirce Seamount
Peirce Seamount
Peirce Seamount, also called Pierce Seamount, is a seamount located in the Pacific Ocean west of the Queen Charlotte Islands, British Columbia, Canada...
(also called Davidson Seamount) and Hodgkins Seamount
Hodgkins Seamount
Hodgkins Seamount is a seamount in the Kodiak-Bowie Seamount chain, located south of Pierce Seamount and north of Bowie Seamount. Hodgkins Seamount has apparently experienced two generically different episodes of volcanism, separated by about 12 million years ago...
.
Diving explorations and studies
The shallow depth of Bowie Seamount makes it the only underwater mountain off the British Columbia Coast easily reached using scuba divingScuba diving
Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater....
equipment. In March 1969, dives were made at the submarine volcano by Canadian Forces Maritime Command
Canadian Forces Maritime Command
The Royal Canadian Navy , is the naval force of Canada. The RCN is one of three environmental commands within the unified Canadian Forces. Operating 33 warships and several auxiliary vessels, the Royal Canadian Navy consists of 8,500 Regular Force and 5,100 Primary Reserve sailors, supported by...
divers from the CSS Parizeau during a new study for device package placement. Two dives were made to the summit where monochrome photographs
Monochrome photography
Monochrome photography is photography where the image produced has a single hue, rather than recording the colours of the object that was photographed. It includes all forms of black-and-white photography, which produce images containing tones of grey ranging from black to white. Most modern...
were taken to establish the environment of Bowie's base and some biological tests were gathered to detect possible harmful organisms, including plants, animals, or bacteria. These specimens were identified at the Pacific Biological Station in Nanaimo, creating a list of eleven varieties of sea bottom invertebrates.
Rockfish
Rockfish may refer to one of the following fishes:* One of several species in the Sebastes genus of the Sebastidae family, including the Shortraker rockfish, Rougheye rockfish, Blue rockfish, Yellow tail rockfish and many others....
floating on top of Bowie's flat-topped summit and a variety of bottom life. A number of monochrome photographs were taken and a few seaweed
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
s were gathered for documents, but no species record was created for other types of oceanic life around Bowie Seamount.
In November 1996, a release of the National Geographic Magazine
National Geographic Magazine
National Geographic, formerly the National Geographic Magazine, is the official journal of the National Geographic Society. It published its first issue in 1888, just nine months after the Society itself was founded...
comprised a piece of writing titled "Realm of the Seamount", illustrating dives made at Bowie Seamount by two diving explorers named Bill Curtsinger and Eric Hiner. They explored Bowie Seamount down to depths of 50 m (164 ft) using scuba diving equipment while the slopes of the seamount down to 150 m (492.1 ft). Images photographed by the two diving explorers featured one of Bowie's rugged peaks covered with thick seaweeds and multicoloured sea bottom invertebrates. Thick groups of young rockfish were detected on Bowie's steep flanks.
Scientist Bill Austin of Khoyatan Marine Lab in the Northeast Pacific looked over a video film earned throughout the National Geographic dives to verify the flora
Flora
Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...
and fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...
of the sea bottom surrounding Bowie Seamount. From the video film, Austin recognized some of the most noticeable invertebrates and noted that a few species more regularly occurring between high-tide and low-tide
Tide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
marks and shallow environments were found deeper than might normally be expected, and were bigger than normal.
A team of five divers visited the seamount August 3–5, 2003 and conducted a biological and photographic survey of the summit down to depths of about 40 m (131.2 ft). A total of 18 taxa of algae, 83 taxa of conspicuous invertebrates and 12 taxa of fishes were documented, approximately 180 underwater still photographs were taken and approximately 90 minutes of digital video were recorded. Of particular note were the dense schools of rockfish hovering over the summit and numerous curious prowfish.
Indigenous people
To the Haida Nation, the indigenous peopleIndigenous peoples of the Pacific Northwest Coast
The Indigenous peoples of the Pacific Northwest Coast are the pre-Columbian inhabitants of the Pacific Northwest Coast, their descendants, and many ethnic groups who identify with those historical peoples. They are now situated within the Canadian Province of British Columbia and the U.S...
who played a key role to establish the Bowie Seamount Marine Protected Area, the submarine volcano is called Sgaan Kinghlas. In their language it means "Supernatural Being Looking Outward".
This seamount has long been recognized by the Haida Nation as a special place. Guujaaw
Guujaaw
Guujaaw is a traditional singer, wood carver, traditional medicine practitioner and political activist. He is a Haida, of the Raven Clan of Skedans.-Background:Beginning in the 1970s, Guujaaw worked to protect Gwaii Haanas from logging activity...
, President of the Council of the Haida Nation, has said: "Sgaan Kinghlas represents a shift in recognizing the need for respect and care for the Earth. This is a very significant turning point in reversing the trends that have been leading to the depletion of life in the sea."
Marine hazard
Given its shallow depth, Bowie Seamount is a potential marine hazard because of the strong storms that strike the British Columbia CoastBritish Columbia Coast
The British Columbia Coast or BC Coast is Canada's western continental coastline on the Pacific Ocean. The usage is synonymous with the term West Coast of Canada....
during winter. Waves have been recorded with heights of more than 20 m (65.6 ft), enough to expose the summit and cause devastation to any vessel transitting the area. For this reason, Bowie Seamount is recognized as a hazard to navigation and is avoided by shipping vessels.
See also
- Volcanism of Canada
- Volcanism of Western CanadaVolcanism of Western CanadaVolcanism of Western Canada produces lava flows, lava plateaus, lava domes, cinder cones, stratovolcanoes, shield volcanoes, submarine volcanoes, calderas, diatremes and maars, along with examples of more less common volcanic forms such as tuyas and subglacial mounds.-Volcanic belts:*Anahim...
- List of volcanoes in Canada