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Mount Waesche is a mountain of volcanic origin at the southern end of the
Executive Committee Range The Executive Committee Range () is a range consisting of five major volcanoes, which trends north-south for along the 126th meridian west, in Marie Byrd Land, Antarctica. Location The Executive Committee Range is south of the eastern end of ...
in
Marie Byrd Land Marie Byrd Land (MBL) is an unclaimed region of Antarctica. With an area of , it is the largest unclaimed territory on Earth. It was named after the wife of American naval officer Richard E. Byrd, who explored the region in the early 20th centu ...
,
Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...
. It is high, and stands southwest of
Mount Sidley Mount Sidley is the highest dormant volcano in Antarctica, a member of the Volcanic Seven Summits, the highest volcanoes on each of the seven continents, with a summit elevation of . It is a massive, mainly snow-covered shield volcano, which is ...
, the highest volcano in Antarctica. The mountain lies southwest of the Chang Peak
caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...
and is largely covered with snow and
glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...
s, but there are rock exposures on the southern and southwestern slopes. The volcano may have been active as late as the
Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...
, with
tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...
layers recovered from
ice core An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier ...
s possibly originating from Mount Waesche.
Seismic activity An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...
has been recorded both from the volcano and from an area south of it and might reflect ongoing volcanic activity.


Name and research history

It was discovered by the United States Antarctic Service expedition on a flight on December 15, 1940, and named for Vice Admiral
Russell R. Waesche Russell Randolph Waesche, Sr. (6 January 1886 – 17 October 1946) served as the eighth Commandant of the United States Coast Guard from 1936 to 1946, overseeing the service during World War II. He was the U.S. Coast Guard's longest serving comm ...
, United States Coast Guard, member of the Antarctic Service Executive Committee. Field studies took place in 1999-2000 and 2018–2019.


Geography and geomorphology

Mount Waesche lies in
Marie Byrd Land Marie Byrd Land (MBL) is an unclaimed region of Antarctica. With an area of , it is the largest unclaimed territory on Earth. It was named after the wife of American naval officer Richard E. Byrd, who explored the region in the early 20th centu ...
, one of the most inaccessible areas of Antarctica. It is one of 18 volcanoes in that region, which were active from the
Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...
to recent times. The origin of volcanic activity there has been correlated to the activity of a
mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic ho ...
underneath the crust. The region also includes the highest volcano in Antarctica,
Mount Sidley Mount Sidley is the highest dormant volcano in Antarctica, a member of the Volcanic Seven Summits, the highest volcanoes on each of the seven continents, with a summit elevation of . It is a massive, mainly snow-covered shield volcano, which is ...
, which reaches height. There may be as many as 138 volcanoes buried underneath the ice. Mount Waesche volcano is high. It is a double volcano, with the north-northeasterly Chang Peak
caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...
and the south-southwesterly Mount Waesche proper. The Chang Peak caldera is wide and the largest in Marie Byrd Land; Mount Waesche rises almost over and lies on the rim of the caldera. Mount Waesche is the more conspicuous peak and
lava flow Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...
s crop out on its southern and southwestern flank, while a wide caldera lies at its summit. On the northern side of Chang Peak caldera lies a high outcrop, and it and another outcrop consist of
pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicula ...
and vitrophyre. Both volcanoes appear to be mainly formed by lava. At least five
parasitic vent A parasitic cone (also adventive cone, satellite cone, satellitic cone or lateral cone) is the cone-shaped accumulation of volcanic material not part of the central vent of a volcano. It forms from eruptions from fractures on the flank of the ...
s lie on the volcano, with several aligned on radial
fissure vent A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive activity. The vent is often a few metres wide and may be many kilo ...
s; they are
cinder cone A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...
s and
scoria cone A cinder cone or scoria cone is a steep, conical landform of loose pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are formed by explosive eruptions or l ...
s and have erupted
cinder Cinder or Cinders may refer to: In general * Ember, also called cinder * Ash, also called cinder * Scoria, or cinder, a type of volcanic rock In computing * Cinder (programming library), a C++ programming library for visualization *Cinder, Ope ...
, lava and
volcanic bomb A volcanic bomb or lava bomb is a mass of partially molten rock (tephra) larger than 64 mm (2.5 inches) in diameter, formed when a volcano ejects viscous fragments of lava during an eruption. Because volcanic bombs cool after they l ...
s. A long large radial dyke projects from Mount Waesche and is the only part of the edifice where hyaloclastic
tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...
crops out. The Bennet Saddle separates Mount Waesche from Mount Sidley to the northeast. Mount Waesche is largely covered with snow and features several alpine
glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...
s as well as a
blue-ice area A blue-ice area is an ice-covered area of Antarctica where wind-driven snow transport and sublimation result in net mass loss from the ice surface in the absence of melting, forming a blue surface that contrasts with the more common white Ant ...
within the
West Antarctic Ice Sheet The West Antarctic Ice Sheet (WAIS) is the segment of the Antarctic ice sheet, continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. It is cla ...
; this blue-ice area has an extent of and a number of
tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...
layers crop out from the ice. Most of these tephra layers come from Mount Waesche, but some originate at
Mount Takahe Mount Takahe is a snow-covered shield volcano in Marie Byrd Land, Antarctica, from the Amundsen Sea. It is a mountain with parasitic vents and a caldera up to wide. Most of the volcano is formed by trachytic lava flows, but hyaloclastite is ...
and
Mount Berlin Mount Berlin is a glacier-covered volcano in Marie Byrd Land, Antarctica, from the Amundsen Sea. It is a roughly mountain with parasitic vents that consists of two coalesced volcanoes: Berlin proper with the Berlin Crater and Merrem Peak wi ...
and their age ranges from 118,000 years to
Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...
. Two particularly conspicuous tephra layers from Mount Waesche are known as the "Great Wall" and "Yellow Wall". The volcano emerges through and is surrounded by the
West Antarctic Ice Sheet The West Antarctic Ice Sheet (WAIS) is the segment of the Antarctic ice sheet, continental ice sheet that covers West Antarctica, the portion of Antarctica on the side of the Transantarctic Mountains that lies in the Western Hemisphere. It is cla ...
. The ice sheet reaches an elevation of about above sea level at Mount Waesche and flows southward towards the
Ross Ice Shelf The Ross Ice Shelf is the largest ice shelf of Antarctica (, an area of roughly and about across: about the size of France). It is several hundred metres thick. The nearly vertical ice front to the open sea is more than long, and between high ...
. Blue ice is found in some areas. Glacial activity has altered the volcano, generating glacial striae and roches moutonnees on the older volcanic rocks and
frost shattering Frost weathering is a collective term for several mechanical weathering processes induced by stresses created by the freezing of water into ice. The term serves as an umbrella term for a variety of processes, such as frost shattering, frost w ...
landforms and
solifluction Solifluction is a collective name for gradual processes in which a mass moves down a slope ("mass wasting") related to freeze-thaw activity. This is the standard modern meaning of solifluction, which differs from the original meaning given to i ...
ridges.
Glacial drift In geology, drift is a name for all sediment (clay, silt, sand, gravel, boulders) transported by a glacier and deposited directly by or from the ice, or by glacial meltwater. Drift is often subdivided into unstratified (unsorted) drift ( glac ...
lies on the ice-free southwestern flank. In turn, glacial
moraine A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a gla ...
s have been overrun by lava flows. Two sets of moraines formed by volcanic debris – one containing ice, the other without – lie on the southern and southwestern flank, reaching heights of and lengths of about .
Surface exposure dating Surface exposure dating is a collection of geochronological techniques for estimating the length of time that a rock has been exposed at or near Earth's surface. Surface exposure dating is used to date glacial advances and retreats, erosion hist ...
has indicated that they belong to an ice highstand that occurred about 10,000 years ago and that the volcanic rocks were probably extracted from underneath the ice. However, large parts of the volcano are exposed on its southwestern flank and apart from glacial erosion
aeolian erosion Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials ...
has taken place on the volcano.


Geology

Mount Waesche is part of the
Executive Committee Range The Executive Committee Range () is a range consisting of five major volcanoes, which trends north-south for along the 126th meridian west, in Marie Byrd Land, Antarctica. Location The Executive Committee Range is south of the eastern end of ...
, which from north to south includes Mount Hampton, Mount Cumming with the parasitic vent Annexstad Peak, Mount Hartigan, Mount Sidley with
Doumani Peak The Executive Committee Range () is a range consisting of five major volcanoes, which trends north-south for along the 126th meridian west, in Marie Byrd Land, Antarctica. Location The Executive Committee Range is south of the eastern end o ...
and Chang Peak-Mount Waesche. These mountains are all volcanic and feature ice-filled calderas, and many are paired volcanoes. Volcanic activity appears to be moving southward at a rate of .
Seismic activity An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...
recorded in 2010 and 2011 south of Mount Waesche may indicate ongoing
magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma (sometimes colloquially but incorrectly referred to as ''lava'') is found beneath the surface of the Earth, and evidence of magmatism has also ...
tic activity south of the youngest volcano. Chang Peak and Mount Waesche appear to be located outside of the Executive Committee Range volcanic lineament. The volcano erupted comendite,
hawaiite Hawaiite is an olivine basalt with a composition between alkali basalt and mugearite. It was first used as a name for some lavas found on the island of Hawaii. It occurs during the later stages of volcanic activity on oceanic islands such as Ha ...
and
mugearite Mugearite () is a type of oligoclase-bearing basalt, comprising olivine, apatite, and opaque oxides. The main feldspar in mugearite is oligoclase. Mugearite is a sodium-rich member of the alkaline magma series. In the TAS classification of volc ...
, with the former found at Chang Peak and the latter two at Mount Waesche proper; the parasitic cones have erupted a mugearite-
benmoreite Benmoreite is a volcanic rock of intermediate composition. It is a silica-undersaturated sodium-rich variety of trachyandesite (the other kind is latite) and belongs to the alkaline suite of igneous rocks. It was named after Ben More, a mount ...
succession. The occurrence of
rhyolite Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matri ...
has also been reported. There appear to be two groups of volcanic rocks at Mount Waesche.
Phenocryst image:montblanc granite phenocrysts.JPG, 300px, Granites often have large feldspar, feldspathic phenocrysts. This granite, from the Switzerland, Swiss side of the Mont Blanc massif, has large white phenocrysts of plagioclase (that have trapezoid sh ...
s at Chang Peak include
aenigmatite Aenigmatite, also known as cossyrite after Cossyra, the ancient name of Pantelleria, is a sodium, iron, titanium inosilicate mineral. The chemical formula is Na2Fe2+5TiSi6O20 and its structure consists of single tetrahedral chains with a repeat u ...
,
alkali feldspar Feldspar ( ; sometimes spelled felspar) is a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagiocla ...
,
ilmenite Ilmenite is a titanium-iron oxide mineral with the idealized formula . It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints, printi ...
and
quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
and at Mount Waesche
olivine The mineral olivine () is a magnesium iron Silicate minerals, silicate with the chemical formula . It is a type of Nesosilicates, nesosilicate or orthosilicate. The primary component of the Earth's upper mantle (Earth), upper mantle, it is a com ...
,
plagioclase Plagioclase ( ) is a series of Silicate minerals#Tectosilicates, tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continu ...
and titanaugite.
Granulite Granulites are a class of high-grade metamorphic rocks of the granulite facies that have experienced high-temperature and moderate-pressure metamorphism. They are medium to coarse–grained and mainly composed of feldspars sometimes associated ...
and
pyroxenite Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite. Pyroxenites are classified into clinopyroxenites, orthopyroxenites, and the w ...
xenolith A xenolith ("foreign rock") is a rock (geology), rock fragment (Country rock (geology), country rock) that becomes enveloped in a larger rock during the latter's development and solidification. In geology, the term ''xenolith'' is almost exclusi ...
s have also been found. Despite their proximity, Mount Sidley and Mount Waesche have erupted distinctly different rocks. Unusually for volcanoes in Marie Byrd Land, the chemistry of volcanic rocks at Mount Waesche appears to have changed over time. The total volume of rocks is about .


Eruption history

The development of Mount Waesche began in the
Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Plio-Pleistocene The Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene and Pleistocene epochs—marking from about 5&n ...
tephra Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, ...
layers found in the
Southern Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...
may originate at Mount Waesche. It appears that volcanism in the Executive Committee Range moved southwards over time, beginning at Mount Hampton and eventually arriving at Mount Waesche which is the young volcanic centre of the range. Chang Peak grew first, 1.6 million years ago or between 2.01.1 million years ago, while Mount Waesche formed within or about 1 million years ago; the youngest rocks at Waesche are less than 100,000 years old whereas there is no evidence of recent activity at Chang Peak. Argon-argon dating on rocks that today form moraines has yielded ages of about 200,000 years to over 500,000 years. One flank vent has been dated to be 170,000 years old and some rocks are too young to be dated by potassium-argon dating. A major pulse of lava flow emissions appears to have occurred 200,000-100,000 years ago and an older episode 500,000-300,000 years ago. The volcano was active during the
Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...
and may be a source of tephra found in
ice core An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier ...
s. A layer of
volcanic ash Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, produced during volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to r ...
, about 8,000 years old, that was identified in the region through
radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
data probably originated at Mount Waesche. The volcano today is considered to be "probably active" or "possibly active". A magmatic system may exist south of Mount Waesche at depth below the ice. Present-day seismic activity has been recorded at Mount Waesche, but it might be either volcanic/tectonic or caused by ice movement. Future eruptions are unlikely to have any impact beyond the surroundings of the volcano.


See also

*
List of volcanoes in Antarctica This is a list of volcanoes in Antarctica. Table A 2017 study claimed to have found 138 volcanoes, of which 91 were previously unknown. Some volcanoes are entirely under the ice sheet. Unconfirmed volcanoes are not included in the table below. ...


Notes


References


Sources

* * * * * * * * *


Bibliography

* * {{DEFAULTSORT:Waesche, Mount Polygenetic shield volcanoes Volcanoes of Marie Byrd Land Inactive volcanoes Executive Committee Range Shield volcanoes of Antarctica