Shackleton Range
Shackleton Range | |
---|---|
Highest point | |
Peak | Holmes Summit |
Elevation | 1,875 m (6,152 ft) |
Geography | |
Continent | Antarctica |
Region | Coats Land |
Range coordinates | 80°30′S 25°00′W / 80.500°S 25.000°W[1] |
The Shackleton Range (80°30′S 25°00′W / 80.500°S 25.000°W) is a mountain range in Antarctica that rises to 1,875 metres (6,152 ft) and extends in an east–west direction for about 100 miles (160 km) between the Slessor and Recovery Glaciers.
Surveys
The
Geology
The range is at the northwestern edge of the
The Haskard Group and
Tectonic history
The range comprises three separate terranes with very different histories. Analysis of geochronological data in these terranes implies that East Antarctica finally came together during the Pan-African orogeny, and its components were separate earlier in the Mesoproterozoic.[4]
Southern Terrane
The southern belt, exposed in the Read Mountains, has medium- to high-grade metamorphic rocks classified as the Read Group. They are mainly composed of partly migmatised quartzitic, basic, calcareous and pelitic rocks. In places they are interlayered with gneissic granites, and intruded by granites and basic rocks. Dating of the metagranites gives ages of around 1,760 and 1,600 million years. Rb–Sr and K-Ar mineral cooling ages are 1650–1550 million years.[2]
The Southern Terrane has detritus up to 2,850 million years old that experienced magmatism from 1,850 to 1,810 million years ago, a metamorphic event between 1,710 and 1,680 years ago, and another metamorphic event 510 million years ago.
Eastern Terrane
The Eastern Terrane holds granitoid rocks formed around 1,060 million years ago during the Grenville orogeny that experienced metamorphism around 600 million years ago. The events at 1,060 and 600 million years ago are similar to the Grenvillian and Pan-African tectonics in Queen Maud Land, suggesting that the Shackleton Range holds part of the Pan African Mozambique/Maud Belt. The
Northern Terrane
The northern belt extends from the Pioneer Escarpment in the east to the northern Haskard Highlands in the west. It has been divided into the Pioneers Group, the Stratton Group, and an ophiolite complex that may be a relic of the Mozambique Ocean.[2] The Northern Terrane has
Topology
The Shackleton Range is 170 kilometres (110 mi) long in an east-west direction and up to 70 kilometres (43 mi) wide.[5] It stretches from the
The Shackleton Range is a rectangular horst rising above major fault zones now under the Slessor and Recovery glaciers.[8] The center of the range is covered by a long ice cap extending from the Fuchs Dome in the west to Shotton Snowfield in the east, and bounded by cliffs as high as 400 metres (1,300 ft). There are areas of rocky outcrop around the margins of the plateau.[6] The Read Mountains on the southeast edge of the range are the highest, at 1,800 to 1,950 metres (5,910 to 6,400 ft), while there are lower peaks at 700 to 900 metres (2,300 to 3,000 ft) along the northern edge.[5] The connected valleys of the north-flowing Gordon Glacier and south-flowing Cornwall Glacier may reflect an underlying fault zone, and have been treated as a divide between the western and eastern portions of the Shackleton Range.[9]
The plateau surface is a discontinuous and faulted undulating peneplain, most visible on the south of the range.[8] The flat areas free of ice at the edge of the Fuchs Dome and Shotton Snowfield and the table mountains that surround them are the remnants of the peneplain.[10] In the Read Mountains there are south-facing cirques as wide as 7 kilometres (4.3 mi) surrounded by high cliffs. The ridges between the cirques stretch over 10 kilometres (6.2 mi) to the south, and in seven cases widen to form flat-topped buttes.[5] In the north and northwest the range is made up of small table mountains and isolated peaks.[5] There are fifteen table mountains in the south of the range, seven in the southwest and just three in the north.[10]
Glacial activity
The geology and origin of glacial erratics, and the evidence of subglacial erosion in the Shackleton Range show that the whole range was once overrun by ice from the south or southeast. The erratics were probably carried north from the
Today, the ice in most of the range still flows north into the Slessor Glacier. However, ice from a small area in the southwest of the snowfield flows south between the Read Mountains and the Stephenson Bastion into the Recovery Glacier, and small glaciers carry ice south from the Read Mountains and Stephenson Bastion.[7]
The high table mountains in the south, exposed to the prevailing winds, have been free of ice for longest and have experienced more weathering than the lower mountains to the north.[10] The Read Mountains have probably been ice-free since before the Quaternary.[11] With few exceptions the table top mountains are free of glacial deposits, although
Topographical Features
In the interior of the range the Fuchs Dome is in the west part, from which the Shotton Snowfield extends to the east. The Otter Highlands are at the west end of the range between the Slessor and Recovery glaciers. Extending eastward along the north (Slessor) side of the range are the Haskard Highlands, La Grange Nunataks, Herbert Mountains and Pioneers Escarpment. From east to west along the south (Recovery) side of the range are the Read Mountains and Stephenson Bastion.[13]
Fuchs Dome
Fuchs Dome (80°36′S 27°50′W / 80.600°S 27.833°W) is a large ice-covered dome rising over 1,525 metres (5,000 ft), between
Shotton Snowfield
80°35′S 23°15′W / 80.583°S 23.250°W. A large snowfield between Herbert Mountains and Pioneers Escarpment on the north and Read Mountains on the south, in the Shackleton Range. The U.S. Navy obtained aerial photographs of the feature in 1967 and it was surveyed by BAS, 1968-71. Named by the UK-APC, 1971, in association with the names of glacial geologists grouped in this area, after
Otter Highlands
Otter Highlands (80°38′S 30°0′W / 80.633°S 30.000°W) is a group of peaks and ridges extending northwest-southeast for 17 nautical miles (31 km; 20 mi) from
Haskard Highlands
The Haskard Highlands (80°30′S 29°15′W / 80.500°S 29.250°W) are a range of peaks and ridges between
La Grange Nunataks
La Grange Nunataks (80°18′S 27°50′W / 80.300°S 27.833°W) is a scattered group of
Herbert Mountains
The Herbert Mountains (80°20′S 25°30′W / 80.333°S 25.500°W) are a conspicuous group of rock summits on the east side of
Pioneers Escarpment
Pioneers Escarpment (80°28′S 21°7′W / 80.467°S 21.117°W) is a mostly snow-covered north-facing escarpment, interrupted by occasional bluffs and spurs, between
Read Mountains
Read Mountains' 80°42′S 24°45′W / 80.700°S 24.750°W is a group of rocky summits, the highest Holmes Summit 1,875 metres (6,152 ft),[21] lying east of Glen Glacier in the south-central part of the Shackleton Range. First mapped in 1957 by the Commonwealth Trans-Antarctic Expedition and named for Professor Herbert H. Read, Chairman of the Scientific Committee and member of the Committee of Management of the Commonwealth Trans-Antarctic Expedition, 1955–58.[1]
Stephenson Bastion
Stephenson Bastion (80°46′S 27°12′W / 80.767°S 27.200°W) is a
Glaciers
The range lies between the Slessor Glacier to the north and the Recovery Glacier to the south, both of which flow west into the Filchner–Ronne Ice Shelf.[13] Slessor Glacier is about 50 kilometres (31 mi) wide and drops from an elevation of over 800 metres (2,600 ft) at the eastern end of the range to about 200 metres (660 ft) at the western end where it enters the Filchner ice shelf. This results in rapid flow, with areas of chaotic ice and many crevasses. The Recovery Glacier is about 80 kilometres (50 mi) wide, and drops from about 1,200 to 800 metres (3,900 to 2,600 ft) along the range. With a lower gradient it flows more slowly and has fewer crevasses.[5] The Schimper Glacier, Gordon Glacier, Stratton Glacier and Blaiklock Glacier flow northwest from the range into the Slessor Glacier. The Glen Glacier and Cornwall Glacier flow south into the Recovery Glacier.[13]
Recovery Glacier
81°10′S 28°00′W / 81.167°S 28.000°W. Glacier, at least 60 miles (97 km) long and 40 miles (64 km) wide at its mouth, flowing west along the south side of the Shackleton Range. First seen from the air and examined from the ground by the CTAF in 1957, and so named because of the recovery of the expedition's vehicles which repeatedly broke into bridged crevasses on this glacier during the early stages of the crossing of Antarctica. Not: Glaciar Expedicion Polar Argentina, Glaciar Falucho.[23]
Slessor Glacier
79°50′S 28°30′W / 79.833°S 28.500°W. Glacier at least 75 miles (121 km) long and 50 miles (80 km) wide, flowing west into the
Glen Glacier
Glacier (80°44′S 25°16′W / 80.733°S 25.267°W) at least 7 miles (11 km) long, flowing south in the Shackleton Range to join Recovery Glacier to the west of Read Mountains. First mapped in 1957 by the CTAE and named for Alexander R. Glen, member of the Committee of Management of the CTAE, 1955–58.[25]
Cornwall Glacier
80°47′S 26°16′W / 80.783°S 26.267°W. Glacier 9 miles (14 km) long, flowing south from
Schimper Glacier
80°18′S 25°05′W / 80.300°S 25.083°W. A glacier in the east part of Herbert Mountains, Shackleton Range, flowing north-northeast into Slessor Glacier. Photographed from the air by the U.S. Navy, 1967, and surveyed by BAS, 1968-71. In association with the names of glacial geologists grouped in the area, named by the UK-APC after Karl Friedrich Schimper (1803–67), German botanist who in 1835 originated the theory of the Ice Age in Europe to account for the distribution of erratic boulders.[27]
Gordon Glacier
80°17′S 26°09′W / 80.283°S 26.150°W. Glacier at least 24 miles (39 km) long, flowing north from Crossover Pass through the Shackleton Range to join Slessor Glacier. First mapped in 1957 by the CTAE and named after George P. Pirie-Gordon, member of the Committee of Management and treasurer of the CTAE, 1955-58.[28]
Stratton Glacier
80°22′S 29°00′W / 80.367°S 29.000°W. A glacier 20 miles (32 km) long, flowing north from Pointer Nunatak and then northwest to the north of Mount Weston, in the Shackleton Range. First mapped in 1957 by the CTAE and named for David G. Stratton, surveyor and deputy leader of the transpolar party of the CTAE in 1956-58.[29]
Blaiklock Glacier
80°30′S 29°51′W / 80.500°S 29.850°W. Glacier 16 miles (26 km) long, flowing north from Turnpike Bluff, then northwest to Mounts Provender and Lowe in the west part of the Shackleton Range. First mapped in 1957 by the CTAE and named for Kenneth V. Blaiklock, leader of the advance party of the CTAE in 1955-56 and surveyor with the transpolar party in 1956-58.[30]
Other features
Crossover Pass
80°38′S 26°30′W / 80.633°S 26.500°W. Pass between Gordon and Cornwall Glaciers in the central part of the Shackleton Range. First mapped in 1957 by the CTAE and so named because this pass, together with Gordon and Cornwall Glaciers, provides a sledging route across the Shackleton Range from north to south.[31]
Warden Pass
80°28′S 28°20′W / 80.467°S 28.333°W. A snow pass at c. 1,000 metres (3,300 ft) trending east-west between the northwest side of Fuchs Dome and Flat Top in the Shackleton Range. The area was surveyed by CTAE in 1957. Named by the UK-APC after Michael A. Warden, BAS general assistant, Halley Station, 1970-72, who worked in the area.[32]
Nostoc Lake
80°24′S 30°05′W / 80.400°S 30.083°W Lake lying 1 mile (1.6 km) southwest of Mount Provender in the west part of the Shackleton Range. First mapped in 1957 by the CTAE and given the generic name of the freshwater alga found growing in the lake.[33]
References
- ^ a b c d e Alberts 1995, p. 607.
- ^ a b c Will et al. 2009, p. 26.
- ^ Laird 1991, pp. 178–179.
- ^ a b c d Will et al. 2009, p. 25.
- ^ a b c d e f g Höfle & Buggisch 1993, p. 183.
- ^ a b Skidmore & Clarkson 1972, p. 69.
- ^ a b Höfle & Buggisch 1993, p. 184.
- ^ a b Skidmore & Clarkson 1972, p. 70.
- ^ Skidmore & Clarkson 1972, p. 71.
- ^ a b c Höfle & Buggisch 1993, p. 185.
- ^ a b Höfle & Buggisch 1993, p. 191.
- ^ Höfle & Buggisch 1993, p. 187.
- ^ a b c Shackleton USGS map.
- ^ Alberts 1995, p. 262.
- ^ Alberts 1995, p. 673.
- ^ Alberts 1995, p. 549.
- ^ Alberts 1995, p. 317.
- ^ Alberts 1995, p. 412.
- ^ Alberts 1995, p. 329.
- ^ Alberts 1995, p. 578.
- ^ Holmes Summit SCAR.
- ^ Alberts 1995, p. 712.
- ^ Alberts 1995, p. 608.
- ^ Alberts 1995, p. 684.
- ^ Alberts 1995, p. 281.
- ^ Alberts 1995, p. 154.
- ^ Alberts 1995, p. 653.
- ^ Alberts 1995, p. 286.
- ^ Alberts 1995, p. 717.
- ^ Alberts 1995, p. 72.
- ^ Alberts 1995, p. 163.
- ^ Alberts 1995, p. 795.
- ^ Alberts 1995, p. 534.
Sources
- Alberts, Fred G., ed. (1995), Geographic Names of the Antarctic (PDF) (2 ed.), United States Board on Geographic Names, retrieved 3 December 2023 This article incorporates public domain material from websites or documents of the United States Board on Geographic Names.
- Höfle, Hans-Christian; Buggisch, Werner (1993), "Glacial Geology and Petrography of Erratics in the Shackleton Range, Antarctica" (PDF), Polarforschung, vol. 63, no. 213, pp. 183–201, retrieved 5 December 2023
- "Holmes Summit", SCAR Composite Gazetteer
- Laird, M.G. (1991), Thomson, M.R.A.; Crame, J.A.; Thomson, J.W. (eds.), Lower-mid-Palaeozoic sedimentation and tectonic patterns on the palaeo-Pacific margin of Antarctica, in Geological Evolution of Antarctica, Cambridge: Cambridge University Press, pp. 178–179, ISBN 9780521372664
- Shackleton Range, United States Geological Survey, 1983, retrieved 4 December 2023 This article incorporates public domain material from websites or documents of the United States Geological Survey.
- Skidmore, Michael J.; Clarkson, Peter D. (1972), "Physiography and Glacial Geomorphology of the Shackleton Range" (PDF), Antarctic Survey Bulletin, no. 30, retrieved 6 December 2023
- Will, Thomas; Zeh, A.; Gerdes, Axel; Frimmel, Hartwig; Millar, I.L.; Schmädicke, E. (2009), "Palaeoproterozoic to Palaeozoic magmatic and metamorphic events in the Shackleton Range, East Antarctica: Constraints from zircon and monazite dating, and implications for the amalgamation of Gondwana", Precambrian Research,