Toney Mountain
Template:Short description Template:Infobox mountain
Toney Mountain (Template:Coord) is an elongated snow-covered shield volcano, Template:Convert long and rising to Template:Convert at Richmond Peak, located Template:Convert southwest of Kohler Range in Marie Byrd Land, Antarctica.Template:Sfn
Geology
Toney Mountain is an elongated volcanic massif that rises Template:Convert<ref name="WilchMcIntosh2021b">Template:Cite journal</ref>-Template:Convert above the ice<ref name="WilchMcIntosh2021"> Template:Cite journal</ref> and may be Antarctica's tallest volcano.<ref>Template:Cite journal</ref> The area covered by Toney Mountain is about Template:Convert<ref name="WilchMcIntosh2021b" /> and is a basaltic lava plateau.<ref name="LeMasurier1990" /> A Template:Convert wide summit caldera tops the volcano,<ref name=GVP/> and is elongated in east–west direction; this orientation is shared with calderas on other volcanoes in Marie Byrd Land and reflects regional tectonic stress. The slopes of the volcano feature parasitic vents<ref name="Paulsen2010">Template:Cite journal</ref> and glacial corries,<ref name="AndrewsLeMasurier1973" /> and are much steeper north of the volcano than south of it. Most of the mountain is covered by ice and its eastern sector may be a crater.<ref>Template:Cite journal</ref> That the mountain is mostly ice covered makes it difficult to determine its composition, the origin of the elongated shape of the volcano and the volcanological relation between the parasitic cinder cones and the main volcanic pile. Its volume may be about Template:Convert.<ref name="LeMasurier1990" />
The plateau and parasitic cones are formed by hawaiite and the few outcrops on the main volcano by benmoreite and comendite.<ref name="LeMasurier1990" /> Latite has been reported as well.<ref name="WilchMcIntosh2021" /> They contain phenocrysts of olivine, plagioclase, pyroxene and titanaugite in the former and of clinopyroxene, feldspar and olivine.<ref name="LeMasurier1990" />
An age of 9.6<ref name="WilchMcIntosh2021" />-9.1 million years ago has been obtained on a basaltic lava flow beneath the volcano,<ref name="AndrewsLeMasurier1973">Template:Cite journal</ref> and it has been inferred that the basal plateau formed between 10.1 and 9.1 million years ago. The massif is younger, with ages ranging from 1 million years in its lower parts<ref name="LeMasurier1990" /> to 500,000 years ago. Holocene eruptions may have also occurred at Toney Mountain as indicated by 30 kyr ash layers in ice cores from Byrd Station,<ref name=GVP>Template:Cite gvp</ref> although Mount Takahe and Mount Waesche are also candidates.<ref name="LeMasurier1990">Template:Cite book</ref> During that time period, a number of volcanic eruptions occurred in Antarctica as recorded by ash layers in ice; this coincides with the coldest period of the Wisconsin glaciation and it is possible that the effects of ash clouds from the Antarctic eruptions caused this period of cold global temperatures.<ref>Template:Cite journal</ref> On the other hand, it is also possible that growing ice sheets during this period compressed magma chambers and thus triggered explosive eruptions.<ref>Template:Cite journal</ref> Currently, ongoing glacial retreat is causing uplift in the region.<ref>Template:Cite conference</ref>
Geological setting
Toney Mountain lies in Marie Byrd Land, a tectonically and volcanically active region of Antarctica. There, a layer of basaltic rocks up to Template:Convert thick underlie a series of felsic volcanic edifices. These basaltic rocks in turn are emplaced above a Paleozoic basement with granite intrusions of Devonian-Cretaceous, which crops out in some mountain ranges.<ref>Template:Cite journal</ref> Beneath Toney Mountain, the basaltic floor rises from an elevation of Template:Convert beneath sea level, and the volcano is situated on the floor of a graben. The region is further characterized by a Template:Convert large dome-like uplift, part of the West Antarctic Rift System,<ref>Template:Cite book</ref> and it may reflect the presence of a stationary hotspot.<ref name="LeMasurier1990" />
Exploration and naming
Toney Mountain was probably among those viewed from a distance by Admiral Richard E. Byrd and others of the United States Antarctic Service (USAS) in plane flights from the ship Bear in February 1940. It was mapped in December 1957 by the oversnow traverse party from Byrd Station to the Sentinel Range, 1957–58, led by C.R. Bentley who proposed the name. It was named after George R. Toney, scientific leader at Byrd Station in 1957, a participant in several Antarctic and Arctic operations, serving in both field and administrative capacities.Template:Sfn
Features
Named features of Toney Mountain include, from west to east, Williamson Ridge, Ellis Cone, Downs Cone, Boeger Peak, Richmond Peak, Davey Peak, Roberts Cirque, Zurn Peak, Creehan Cliff, Scudder Peak, Spitz Ridge, Nicholson Rock and Gillett Nunataks.Template:Sfn
Williamson Ridge
Template:Coord. Low snow-covered ridge, Template:Convert long and Template:Convert wide, that forms a western extension of Toney Mountain in Marie Byrd Land. Mapped by the United States Geological Survey (USGS) from ground surveys and United States Navy air photos, 1959–71. Named by the United States Advisory Committee on Antarctic Names (US-ACAN) for Paul R. Williamson, ionospheric physicist at Byrd Station in two austral summers, 1967–68 and 1969–70.Template:Sfn
Ellis Cone
Template:Coord. One of several small cones or cone remnants along the southwest side of Toney Mountain. Mapped by USGS from surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Homer L. Ellis, ACC, United States Navy, radar air traffic controller at McMurdo Station, winter party 1968, and chief in charge of the ground controlled approach unit at the Byrd Station skiway landing strip, summer season, 1969–70.Template:Sfn
Downs Cone
Template:Coord. One of several small cones or cone remnants along the southwest side of Toney Mountain. Located Template:Convert west-southwest of Boeger Peak. Mapped by USGS from ground surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Bill S. Downs, AC1, United States Navy, Air Controlman at Williams Field near McMurdo Station in the 1969–70 and 1970-71 austral summers. He wintered at Little America V on the Ross Ice Shelf, 1958.Template:Sfn
Boeger Peak
Template:Coord. Snow-covered peak Template:Convert high situated Template:Convert west of Richmond Peak. Mapped by USGS from surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Alvin C. Boeger, Chief Aerographer's Mate, United States Navy. As a member of the United States Naval Ice Reconnaissance Unit, Boeger made numerous ice reconnaissance flights between New Zealand and Antarctica from October to December 1972 which contributed to ship operations and routing.Template:Sfn
Richmond Peak
Template:Coord. The central and culminating peak Template:Convert high of the Toney Mountain massif. Mapped by USGS from ground surveys and United States Navy air photos, 1959–71. Named by US-ACAN for Addison E. Richmond Jr., of the United States Dept. of State, Chairman of the Interagency Committee on Antarctica, 1971–72.Template:Sfn
Davey Peak
Template:Coord. A small rock peak Template:Convert high Template:Convert west of Scudder Peak on the south side of Toney Mountain. Mapped by USGS from ground surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Gary R. Davey, meteorologist at Byrd Station in 1966.Template:Sfn
Roberts Cirque
Template:Coord. A cirque marked by a sheer rock cliff located just west of Zum Peak along the central-north wall of Toney Mountain. Mapped by USGS from ground surveys and United States Navy air photos, 1959–71. Named by US-ACAN for John H. Roberts III, United States Navy, Chief Commissaryman with the South Pole Station winter party, 1974.Template:Sfn
Zurn Peak
Template:Coord. Rocky peak Template:Convert high rising from the north edge of Toney Mountain, about Template:Convert northeast of Richmond Peak. Mapped by USGS from surveys and United States Navy air photos, 1959–71. Named by US-ACAN for Walter A. Zurn, Station Scientific Leader at South Pole Station, 1972.Template:Sfn
Creehan Cliff
Template:Coord. A cliff about Template:Convert east-northeast of Richmond Peak on the north side of Toney Mountain. Mapped by USGS from ground surveys and United States Navy air photos, 1959–71. Named by US-ACAN for Lieutenant Patrick E. Creehan, MC, United States Navy Reserve, Flight Surgeon of Squadron VXE-6 during Operation Deep Freeze 1971 and 1972.Template:Sfn
Scudder Peak
Template:Coord. Small rock peak just southwest of Spitz Ridge on the south side of Toney Mountain. Mapped by USGS from ground surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Brent E. Scudder, meteorologist at Byrd Station in 1966.Template:Sfn
Cox Bluff
Template:Coord. A rock and ice bluff just west of Spitz Ridge on the north side of Toney Mountain. Mapped by USGS from ground surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Tony L. Cox, geomagnetist-seismologist with the Byrd Station winter party, 1966.Template:Sfn
Spitz Ridge
Template:Coord. A prominent, mainly ice-covered ridge east of Cox Bluff, forming the east end of Toney Mountain. Mapped by USGS from ground surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Armand Lawrence Spitz, ionospheric physicist, who wintered at Byrd Station in 1966 and worked additional summer seasons at Byrd and Hallett Stations.Template:Sfn
Nicholson Rock
Template:Coord. A rock Template:Convert east of Cox Bluff on the mainly snow-covered Spitz Ridge in eastern Toney Mountain massif. Mapped by USGS from surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Charles E. Nicholson, CE2, United States Navy, Construction Electrician at South Pole Station, 1974.Template:Sfn
Gillett Nunataks
Template:Coord. Two mainly snow-covered nunataks at the east end of Spitz Ridge and the Toney Mountain massif. Mapped by USGS from surveys and United States Navy air photos, 1959–66. Named by US-ACAN for Richard D. Gillett, RM1, United States Navy, Radioman at South Pole Station, 1974.Template:Sfn