Fang Ridge

Mount Erebus () is the southernmost active volcano on Earth, located on Ross Island in the Ross Dependency in Antarctica. With a summit elevation of , it is the second most prominent mountain in Antarctica (after Mount Vinson) and the second-highest volcano in Antarctica (after the dormant Mount Sidley). It is the highest point on Ross Island, which is also home to three inactive volcanoes: Mount Terror, Mount Bird, and Mount Terra Nova. It makes Ross Island the sixth-highest island on Earth.

The mountain was named by Captain James Clark Ross in 1841 for his ship, HMS ''Erebus''. The volcano has been active for around 1.3 million years and has a long-lived lava lake in its inner summit crater that has been present since at least the early 1970s. On 28 November 1979, Air New Zealand Flight 901 crashed on Mount Erebus, killing all 257 people on board.

Geology and volcanology

Mount Erebus is the world's southernmost active volcano. It is the current eruptive centre of the Erebus hotspot. The summit contains a persistent convecting phonolitic lava lake, one of five long-lasting lava lakes on Earth. Characteristic eruptive activity consists of Strombolian eruptions from the lava lake or from one of several subsidiary vents, all within the volcano's inner crater. The volcano is scientifically remarkable in that its relatively low-level and unusually persistent eruptive activity enables long-term volcanological study of a Strombolian eruptive system very close (hundreds of metres) to the active vents, a characteristic shared with only a few volcanoes on Earth, such as Stromboli in Italy. Scientific study of the volcano is also facilitated by its proximity to McMurdo Station (U.S.) and Scott Base (New Zealand), both sited on the same island around 35 km away.

Mount Erebus is classified as a polygenetic stratovolcano. The bottom half of the volcano is a shield and the top half is a stratocone. The composition of the current eruptive products of Erebus are anorthoclase-porphyritic tephritic phonolite and phonolite, which are the bulk of exposed lava flow on the volcano. The oldest eruptive products consist of relatively undifferentiated and nonviscous basanite lavas that form the low broad platform shield of Erebus. Slightly younger basanite and phonotephrite lavas crop out on Fang Ridgean eroded remnant of an early Erebus volcanoand at other isolated locations on the flanks of Erebus. Erebus is the world's only presently erupting phonolite volcano.

Lava flows of more viscous phonotephrite and trachyte erupted after the basanite. The upper slopes of Mount Erebus are dominated by steeply dipping (about 30°) tephritic phonolite lava flows with large-scale flow levees. A conspicuous break in slope around 3,200 m ASL calls attention to a summit plateau representing a caldera. The summit caldera was created by an explosive VEI-6 eruption that occurred 18,000 ± 7,000 years ago. It is filled with small volume tephritic phonolite and phonolite lava flows. In the center of the summit caldera is a small, steep-sided cone composed primarily of decomposed lava bombs and a large deposit of anorthoclase crystals known as Erebus crystals. The active lava lake in this summit cone undergoes continuous degassing.

Microscopic gold particles have been found up to 1000 kilometres from Mount Erebus, ranging in size up to 60 micrometres. A 1991 paper shows that these particles condense from the volcano's emissions that include 80 grams of gold vapor daily. This amount of gold vapor is low compared to other volcanoes, but the condensation from vapor into gold particles is the first ever documented.

Researchers spent more than three months during the 2007–08 field season installing an atypically dense array of seismometers around Mount Erebus to listen to waves of energy generated by small, controlled blasts from explosives they buried along its flanks and perimeter, and to record scattered seismic signals generated by lava lake eruptions and local ice quakes. By studying the refracted and scattered seismic waves, the scientists produced an image of the uppermost (top few km) of the volcano to understand the geometry of its "plumbing" and how the magma rises to the lava lake.
These results demonstrated a complex upper-volcano conduit system with appreciable upper-volcano magma storage to the northwest of the lava lake at depths hundreds of meters below the surface.

Ice fumaroles

Mount Erebus is notable for its numerous ice fumaroles – ice towers that form around gases that escape from vents in the surface. The ice caves associated with the fumaroles are dark, in polar alpine environments starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. The life is sparse, mainly bacteria and fungi. This makes it of special interest for studying oligotrophs – organisms that can survive on minimal amounts of resources.

The caves on Erebus are of special interest for astrobiology, as most surface caves are influenced by human activities, or by organics from the surface brought in by animals (e.g. bats and birds) or ground water. The caves at Erebus are at high altitude, yet accessible for study. Some of the caves can reach temperatures of 25 degrees Celsius (77 degrees Fahrenheit), and with light near the cave mouths, in some caves covered by thin overlying ice, the light may reach even deeper and is sufficient to sustain an ecosystem of flora and fauna consisting of moss, algae, arthropods and nematodes.

They are dynamic systems that collapse and rebuild, but persist over decades. The air inside the caves has 80 to 100% humidity, and up to 3% carbon dioxide (CO₂), and some carbon monoxide (CO) and hydrogen (H₂), but almost no methane (CH₄) or hydrogen sulfide (H₂S). Many of them are completely dark, so cannot support photosynthesis. Organics can only come from the atmosphere, or from ice algae that grow on the surface in summer, which may eventually find their way into the caves through burial and melting. As a result, most micro-organisms there are chemolithoautotrophic i.e. microbes that get all of their energy from chemical reactions with the rocks, and that do not depend on any other lifeforms to survive. The organisms survive using CO₂ fixation and some may use CO oxidization for the metabolism. The main types of microbe found there are Chloroflexota and Acidobacteriota. In 2019, the Marsden Fund granted nearly NZ$1 million to the University of Waikato and the University of Canterbury to study the micro-organisms in the geothermal fumaroles.

History

Discovery and naming

Mount Erebus was discovered on 27 January 1841 (and observed to be in eruption), by polar explorer Sir James Clark Ross on his Antarctic expedition, who named it and its companion, Mount Terror, after his ships, HMS ''Erebus'' and HMS ''Terror'' (which were later used and lost by Sir John Franklin on his disastrous Arctic expedition). Present with Ross on HMS ''Erebus'' was the young Joseph Hooker, future president of the Royal Society and close friend of Charles Darwin. Erebus is a dark region in Hades in Greek mythology, personified as the Ancient Greek primordial deity of darkness, the son of Chaos.

Historic sites

The mountain was surveyed in December 1912 by a science party from Robert Falcon Scott's ''Terra Nova'' expedition, who also collected geological samples. Two of the camp sites they used have been recognised for their historic significance:
* Upper “Summit Camp” site (HSM 89) consists of part of a circle of rocks, which were probably used to weight the tent valances.
* Lower “Camp E” site (HSM 90) consists of a slightly elevated area of gravel, as well as some aligned rocks, which may have been used to weight the tent valances.

They have been designated historic sites or monuments following a proposal by the United Kingdom, New Zealand, and the United States to the Antarctic Treaty Consultative Meeting.

Climbing

Mount Erebus' summit crater rim was first achieved by members of Sir Ernest Shackleton's party; Professor Edgeworth David, Sir Douglas Mawson, Dr Alister Mackay, Alex Lagasse, Jameson Adams, Dr Eric Marshall and Phillip Brocklehurst (who did not reach the summit), on 10 March 1908. The ascent was documented in the first chapter of Aurora Australis, the first book to be written and published in Antarctica. Its first known solo ascent and the first winter ascent was accomplished by British mountaineer Roger Mear on 7 June 1985, a member of the "In the Footsteps of Scott" expedition. On 19–20 January 1991, Charles J. Blackmer, an iron-worker for many years at McMurdo Station and the South Pole, accomplished a solo ascent in about 17 hours completely unsupported, by snow mobile and on foot.

Robotic exploration

In 1992, the inside of the volcano was explored by ''Dante I'', an eight legged tethered robotic explorer. ''Dante'' was designed to acquire gas samples from the magma lake inside the inner crater of Mount Erebus to understand the chemistry better through the use of the on-board gas chromatograph, as well as measuring the temperature inside the volcano and the radioactivity of the materials present in such volcanoes. ''Dante'' successfully scaled a significant portion of the crater before technical difficulties emerged with the fibre-optic cable used for communications between the walker and base station. Since ''Dante'' had not yet reached the bottom of the crater, no data of volcanic significance was recorded. The expedition proved to be highly successful in terms of robotic and computer science, and was possibly the first expedition by a robotic platform to Antarctica.

Air New Zealand Flight 901

Air New Zealand Flight 901 was a scheduled sightseeing service from Auckland Airport in New Zealand to Antarctica and return with a scheduled stop at Christchurch Airport to refuel before returning to Auckland. The Air New Zealand flyover service, for the purposes of Antarctic sightseeing, was operated with McDonnell Douglas DC-10-30 aircraft and began in February 1977. The flight crashed into Mount Erebus on 28 November 1979, killing all 257 people on board. Passenger photographs taken seconds before the collision ruled out the "flying in a cloud" theory, showing perfectly clear visibility well beneath the cloud base, with landmarks visible to the left and to the right of the aircraft. The mountain directly ahead was lit by sunlight shining from directly behind the aircraft through the cloud deck above, resulting in a lack of shadows that made Mount Erebus effectively invisible against the overcast sky beyond in a classic whiteout (more accurately, "flat-light") phenomenon.Royal Commission Report, para 40(a) Further investigation of the crash showed a navigational error in flight documentation by Air New Zealand and a cover-up that resulted in about $100 million in lawsuits. Air New Zealand discontinued its flyovers of Antarctica. Its final flight was on 17 February 1980. During the Antarctic summer, snow melt on the flanks of Mount Erebus continually reveals debris from the crash that is visible from the air.

Craters

Main Crater

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The topographic feature that rises to about high and forms the primary summit crater of Mount Erebus.
Inner Crater, which lies within Main Crater, contains an anorthoclase-phonolite lava lake.

Inner Crater

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The topographic feature that embraces the crater within the floor of Main Crater, at the summit of Mount Erebus.
Inner Crater contains an active anorthoclase-phonolite lava lake.
The name derives from the fact that the crater is within the Main Crater of Mount Erebus.

Side Crater

A nearly circular crater, about high, situated at the summit of Mount Erebus on the southwest crater rim.
Named for its location on the side of the main summit cone of Mount Erebus.

Western Crater

A small circular crater at high on the western slope of the summit of Mount Erebus.
So named for its location.

Summit features

Mount Erebus has several named features on its slopes, including a number of rock formations.
Features around the summit of the mountain include:

Helo Cliffs

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Prominent cliffs at about high on the north rim of the summit caldera of Mount Erebus. The name derives from a nearby United States Coast Guard (USCG) HH-52A helicopter (CG 1404) which lost power and crashed while enroute from McMurdo Station to Cape Bird, Jan. 9, 1971. The four crew and passengers were not injured, but the helicopter was abandoned because of its location.

Seismic Bluff

Steep bluff at about high on the southwest rim of the summit caldera of Mount Erebus.
So named after a seismic station nearby.

Tower Ridge

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A ridge at about high that descends the southwest slope of the summit crater of Mount Erebus. So named because the ridge is defined by a series of fumarolic ice towers.

Camp Slope

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A concave slope, about high, just south of Crystal Slope on the west side of the summit cone of Mount Erebus. The feature is the site of a slump which has occurred off the crater rim. It is also a former camp site used by summit parties. A small hut is located on the upper part of the slope.

Robot Gully

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A gully at about high on the northwest side of the summit crater of Mount Erebus. The feature was used as the access route from a NASA robot called Dante that was carried to the crater rim, Jan. 1, 1993.

Crystal Slope

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A western slope, high, between Camp Slope and Robot Gully, leading down from the summit crater rim of Mount Erebus. So named because the slope includes a talus of large anorthoclase feldspar crystals.

Nausea Knob

A prominent outcropping of jumbled rocks, high, formed as a lava flow on the northwest upper slope of the active cone of Mount Erebus.
The feature is near a camp site used mainly in the 1970s by teams working at the summit of the volcano.
So named because many working at the camp suffered from nausea due to high elevation mountain sickness.

Northern features

Features on the northern slopes include:

Abbott Peak

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Pyramidal peak on the north side of Mount Erebus,
between it and Mount Bird. Charted by the British Antarctic Expedition under Scott,
1910-13, and named for Petty Officer George P. Abbott, Royal Navy, a
member of the expedition.

Krall Crags

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Two rock summits rising to over high on the northwest slope of Mount Erebus. The feature is west-northwest of Abbott Peak. At the suggestion of P.R. Kyle, named by Advisory Committee on Antarctic Names (US-ACAN) (2000) after Sarah Krall who worked over 10 years in providing support to science in Antarctica. She was cook and camp manager at the lower Erebus Hut during the 1992-93 NSF-NASA Dante robot experiment on Mount Erebus. She also managed the food room at McMurdo Station, was the hovercraft pilot, and has also been a helicopter technician.

Tarr Nunatak

A nunatak rising to about high on the northwest slope of Mount Erebus.
The feature is south-southwest of Abbott Peak.
Named by New Zealand Geographic Board (NZGB) (2000) after Sergeant L.W. (Wally) Tarr, Royal New Zealand Air Force, aircraft mechanic with the New Zealand contingent of the Commonwealth Trans-Antarctic Expedition (CTAE), 1956-58.

Fang Ridge

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A conspicuous ridge on the northeast slope of Mount Erebus.
It is a much denuded portion of the original caldera rim left by a catastrophic eruption.
So named, probably for its curved shape, by Frank Debenham of the British Antarctic Expedition, 1910–13, who made a plane table survey in 1912.

The Fang

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A distinctive toothlike peak, high, which forms the highest point of Fang Ridge.
Descriptively named by Frank Debenham of British Antarctic Expedition (British Antarctic Expedition), 1910–13, who made a plane table survey of the vicinity in 1912.

Millennium Peak

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A peak rising to about high on the northeast slope of Mount Erebus, east-northeast of the Erebus summit.
So named by Advisory Committee on Antarctic Names (US-ACAN) in the millennium year 2000.

Coleman Peak

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A peak rising to about high on the northeast slope of Mount Erebus, east of the summit of Fang Ridge. Named by the New Zealand Geographic Board (NZGB) (2000) after Father Coleman, a New Zealand chaplain, who traveled to Antarctica many times with the United States Antarctic Program.

Te Puna Roimata Peak

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A peak about high, located west of Terra Nova Glacier and south of Lewis Bay on the lower northeast slope of Mount Erebus. On November 28, 1979, an Air New Zealand McDonnell Douglas DC-10 aircraft on a scenic flight from Auckland crashed near this peak claiming the lives of 237 passengers from eight countries and a crew of 20. In 1987, a stainless steel memorial cross was erected west of the peak.
Te Puna Roimata Peak (meaning spring of tears) was named by the New Zealand Geographic Board (NZGB) in 2000.

Southern features

Features of the southern slopes of the mountain include:

Hoopers Shoulder

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An independent cone at an elevation of high on the west slopes of Mount Erebus. From McMurdo Sound it appears as a perfect pyramid of black rock, standing out as a splendid mark against the background of the ice and almost on a line from Cape Royds to the crater of Mount Erebus.
The cone itself is about high high and is surrounded by a deep moat or ditch, caused by the sweeping action of strong winds.
It was named by F. Debenham on the second ascent of Mount Erebus for F.J. Hooper, a steward of the British Antarctic Expedition, 1910-13.
Hooper was one of the party making the second ascent.

Cashman Crags

Two rock summits at about high on the west slope of Mount Erebus.
The feature is southwest of Hoopers Shoulder.
At the suggestion of P.R. Kyle, named by United States Advisory Committee on Antarctic Names (US-ACAN) (2000) after Katherine V. Cashman, United States Antarctic Research Program (USARP) team member on Mount Erebus in 1978-79 while a Fulbright scholar at Victoria University of Wellington; worked again on Mount Erebus, 1988–89; later Professor of Geology, University of Oregon.

Williams Cliff

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A prominent rock cliff that stands out from the ice-covered southwest slopes of Mount Erebus, situated east of Cape Barne.
This rock cliff was mapped by the British Antarctic Expedition under Scott, 1910–13, and identified simply as "Bold Cliff on maps resulting from that expedition.
It was named Williams Cliff by the US-ACAN in 1964 to commemorate Richard T. Williams, who lost his life when his tractor broke through the ice at McMurdo Sound in January 1956.

Tech Crags

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A narrow broken ridge south of Williams Cliff on Ross Island. The feature rises to about high and marks a declivity along the north flank of broad Turks Head Ridge, from which ice moves to Pukaru Icefalls. Named by US-ACAN (2000) after the New Mexico Institute of Mining and Technology, known as New Mexico Tech. From 1981, many Tech students under the direction of Philip R. Kyle, have undertaken graduate research projects (thesis and dissertation) on Mount Erebus.

Three Sisters Cones

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Three aligned cones at an elevation of about high on the southwest slopes of Mount Erebus.
Named by members of the British Antarctic Expedition, 1910–13, under Scott.

Turks Head Ridge

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A mostly ice-covered ridge extending from Turks Head for a few miles up the slopes of Mount Erebus.
Mapped by the British Antarctic Expedition, 1910–13, under Scott and so named because of its association with Turks Head.

Esser Bluff

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A rock bluff rising to about high on the southeast margin of Turks Head Ridge. The bluff is east-northeast of Grazyna Bluff. At the suggestion of P.R. Kyle, named by US-ACAN (2000) after Richard Esser, a member of New Mexico Tech field parties on Mount Erebus in the 1993–94 and 1994-95 seasons; later a technician in the New Mexico Geochronology Lab at NM Tech, where he has dated many rocks from Antarctica.

Grazyna Bluff

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A rock bluff rising to about high in the south part of Turks Head Ridge.
The bluff is north-northeast of Turks Head.
At the suggestion of P.R. Kyle, named by US-ACAN (2000) after Grazyna Zreda-Gostynska, who worked on Mount Erebus in 1989-90 as a member of the New Mexico Institute of Mining and Technology team. A Ph.D. student at NMIMT, she completed her doctoral dissertation on the gas emissions from Mount Erebus.

Glacier Ridge

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A broad north–south ridge, long and wide, on the south slopes of Mount Erebus. Completely ice covered, the ridge descends from about high to high, terminating northwest of Tyree Head.
In association with the names of expedition ships grouped on this island, named after United States Coast Guard Cutter (USCGC) ''Glacier'', an icebreaker which for three decades, 1955-56 to 1986-87, supported scientific activity in Antarctica and Ross Sea on virtually an annual basis.
From 1955-56, ''Glacier'' operated as a US Navy ship.
Along with other Navy icebreakers, Glacier was transferred to the US Coast Guard fleet, June 1966, from which she operated until decommissioned, June 1987.

Glaciers

Fang Glacier

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A glacier on the west side of Fang Ridge, separating the old and new craters of Mount Erebus.
Charted by Frank Debenham of the BrAE, 1910–13, and named by him in association with Fang Ridge.

Erebus Glacier

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A glacier draining the lower south slopes of Mount Erebus, Ross Island, and flowing west to Erebus Bay where it forms the floating Erebus Glacier Tongue.
Named in association with Mount Erebus by the British National Antarctic Expedition (BrNAE), 1901–04, under Scott.

Erebus Glacier Tongue

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The seaward extension of Erebus Glacier from Ross Island, projecting into Erebus Bay where part of it is floating.
Charted and named by the BrNAE under Scott, 1901-04.

Barne Glacier

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Steep glacier which descends from the west slopes of Mount Erebus and terminates on the west side of Ross Island between Cape Barne and Cape Evans where it forms a steep ice cliff.
Discovered by the BrNAE, 1901–04, under Scott.
Named by the British Antarctic Expedition, 1907–09, under Shackleton after nearby Cape Barne.

See also

* List of volcanoes in Antarctica
* Lower Erebus Hut – home of MEVO

References

Sources

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External links

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The Mount Erebus Volcano Observatory


A picture from space of the lava lake at the summit of Mount Erebus



A panoramic view from the summit of Mount Erebus

Video of Mount Erebus erupting in 2005

List of published research about Mount Erebus, maintained by Mount Erebus Volcano Observatory

{{DEFAULTSORT:Erebus, Mount
Active volcanoes
Extreme points of Earth
Stratovolcanoes of New Zealand
Volcanoes of Ross Island
Hotspot volcanoes
VEI-6 volcanoes
Mount Erebus
Lava lakes
Pleistocene stratovolcanoes
Holocene stratovolcanoes
Stratovolcanoes of Antarctica
Mount Erebus disaster