A nunatak (from Inuit nunataq ) is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They often form natural pyramidal peaks . Isolated nunataks are also called glacial islands, and smaller nunataks rounded by glacial action may be referred to as rognons .
16-694: The Du Toit Nunataks ( 80°43′S 25°50′W / 80.717°S 25.833°W / -80.717; -25.833 ) are a group of nunataks between Cornwall Glacier and Glen Glacier , marking the western end of the Read Mountains in the Shackleton Range of Antarctica. The Du Toit Nunataks were photographed from the air by the United States Navy , 1967, and surveyed by the British Antarctic Survey , 1968–71. In association with
32-571: Is of Greenlandic origin and has been used in English since the 1870s. The term nunatak is typically used in areas where a permanent ice sheet is present and the ridge protrudes above the sheet. Nunataks present readily identifiable landmark reference points in glaciers or ice caps and are often named. While some are isolated, they can also form dense clusters, such as Queen Louise Land in Greenland. Nunataks are generally angular and jagged, hampering
48-588: The Tithonian stage (1870), regarded as equivalent to the Purbeck Group and Wealden formations. Zittel published Aus der Urzeit and Die Sahara (1883). In 1899, he published Geschichte der Geologie und Palaeontologie bis Ende des 19 Jahrhunderts , a monumental history of the progress of geological science. Zittel was president of the Royal Bavarian Academy of Sciences from 1899, and in 1894 he
64-647: The University of Munich , with the charge of the state collection of fossils. In 1873–1874, he accompanied the Friedrich Gerhard Rohlfs 's expedition to the Libyan Desert , the primary results of which were published in Über den geologischen Bau der libyschen Wuste (1880), and further details in the Palaeontographica (1883). Zittel was distinguished for his palaeontological researches. From 1869 until
80-479: The 1983 United States Geological Survey map include: 80°44′S 25°36′W / 80.733°S 25.600°W / -80.733; -25.600 . A small debris-covered area with elevation about 1,350 metres (4,430 ft) on the east margin of Du Toit Nunataks, Read Mountains, in the Shackleton Range. Photographed from the air by the U.S. Navy, 1967, and surveyed by BAS, 1968-71. In association with
96-621: The Du Toil Nunataks, Read Mountains, Shackleton Range. Photographed from the air by the U.S. Navy, 1967, and surveyed by BAS, 1968-71. In association with the names of geologists grouped in this area, named by the UK-APC in 1971 after Professor Arie Poldervaart (1919–64), Dutch petrologist known for his research on basaltic rocks. 80°39′S 26°12′W / 80.650°S 26.200°W / -80.650; -26.200 . A rocky summit rising to about 1,450 metres (4,760 ft) and marking
112-405: The close of his life he was chief editor of the Palaeontographica . In 1876, he commenced the publication of his great work, Handbuch der Palaeontologie , which was completed in 1893 in five volumes, the fifth volume on palaeobotany being prepared by W. P. Schimper and A. Schenk. To make his work as trustworthy as possible Zittel made special studies of each great group, commencing with
128-467: The formation of glacial ice on their tops, although snow can accumulate on them. This can contrast strongly with the softer contours of the glacially eroded land after a glacier retreats. They are not greatly affected by frost weathering , given the low frequency of freeze-thaw cycles in areas of ice caps and ice sheets. Typically nunataks are the only places where plant life can survive on ice sheets or ice caps. Lifeforms on nunataks are often isolated by
144-463: The fossil sponges, on which he published a monograph (1877–1879). In 1895, he issued a summary of his larger work entitled Grundzuge der Palaeontologie . In 1880, Zittel was appointed to the geological professorship, and eventually to the directorship of the natural history museum of Munich. His earlier work comprised a monograph on the Cretaceous bivalve mollusca of Gosau (1863–1866); and an essay on
160-451: The names of geologists grouped in this area, named by the UK-APC in 1971 after Frederick Henry Hatch (1864-1932), British consulting geologist; author of standard textbooks on igneous and sedimentary petrology. 80°44′S 25°57′W / 80.733°S 25.950°W / -80.733; -25.950 An east-facing escarpment rising to about 1,300 metres (4,300 ft) and trending northeast–southwest for 3.5 miles (5.6 km) in
176-727: The names of geologists grouped in this area, they were named by the UK Antarctic Place-Names Committee after Alexander Logie du Toit , a South African geologist. The Du Toit Nunataks lie to the south of the Shotton Snowfield to the west end of the Read Mountains . They lie between the Cornwall Glacier and the Glen Glacier , both of which flow south to join the Recovery Glacier , which flows westward past
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#1732884584280192-486: The northest part of Du Toit Nunataks, Read Mountains, Shackleton Range. The feature was surveyed by the CTAE, 1957, photographed from the air by the U.S. Navy, 1967, and further surveyed by BAS, 1968-71. In association with the names of geologists grouped in this area, named by UK-APC in 1971 after Karl Alfred von Zittel (1839–1904), German paleontologist who specialized in the study of fossil sponges. Nunatak The word
208-621: The northwest end of Du Toit Nunataks, Read Mountains, in the Shackleton Range. Photographed from the air by the U.S. Navy, 1967, and surveyed by BAS, 1968-71. In association with the names of geologists grouped in the area, named by the UK-APC after Leonard Frank Spath (1882-1957), British paleontologist and stratigrapher whose study of ammonites made possible the correlation of Mesozoic rocks; paleontologist, British Museum (Natural History), 1912-57. 80°40′S 25°59′W / 80.667°S 25.983°W / -80.667; -25.983 . Cliffs rising to about 1,400 metres (4,600 ft) in
224-707: The south of the Du Toit Nunataks. The Du Toit Nunataks are in the Read Group of the southern belt of the Shackleton Mountains. 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. Download coordinates as: Named geographical features on
240-555: The surrounding ice or glacier, providing unique habitats. Karl Alfred von Zittel Karl Alfred Ritter von Zittel (25 September 1839 – 5 January 1904) was a German palaeontologist best known for his Handbuch der Palaeontologie (1876–1880). Karl Alfred von Zittel was born in Bahlingen in the Grand Duchy of Baden . His father, Karl was a leading liberal cleric in Baden. He
256-464: Was educated at the University of Heidelberg , the University of Paris and the University of Vienna . For a short period he served on the Geological Survey of Austria, and as assistant in the mineralogical museum at Vienna . In 1863, he became teacher of geology and mineralogy in the polytechnic at Karlsruhe , and three years later he succeeded Albert Oppel as professor of palaeontology in
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