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116-542: Download coordinates as: Flint Ridge is immediately north of Commonwealth Glacier . Mount Coleman is to the east, Mount Falconer to the south and Mount McLennan to the west. To the northwest Loftus Glacier flows northeast into the Wilson Piedmont Glacier . 77°30′38″S 162°57′17″E  /  77.510611°S 162.954645°E  / -77.510611; 162.954645 A hill with much exposed rock rising to 850 metres (2,790 ft) high at

232-642: A complex series of orogenic events assembled the eastern parts of Gondwana (eastern Africa, Arabian-Nubian Shield, Seychelles, Madagascar, India, Sri Lanka, East Antarctica, and Australia) c. 750 to 530 Ma . First, the Arabian-Nubian Shield collided with eastern Africa (in the Kenya-Tanzania region) in the East African Orogeny c. 750 to 620 Ma . Then Australia and East Antarctica were merged with

348-599: A continuous arc chain, the direction of subduction was different between the Australian-Tasmanian and New Zealand-Antarctica arc segments. Many terranes were accreted to Eurasia during Gondwana's existence, but the Cambrian or Precambrian origin of many of these terranes remains uncertain. For example, some Palaeozoic terranes and microcontinents that now make up Central Asia, often called the "Kazakh" and "Mongolian terranes", were progressively amalgamated into

464-746: A diversified assemblage of true insects. In Gondwana, in contrast, ice and, in Australia, volcanism decimated the Devonian flora to a low-diversity seed fern flora – the pteridophytes were increasingly replaced by the gymnosperms which were to dominate until the Mid-Cretaceous. Australia, however, was still located near the Equator during the Early Carboniferous, and during this period, temnospondyl and lepospondyl amphibians and

580-472: A few million years, reached its peak at c. 200 Ma , and coincided with the Triassic–Jurassic extinction event . The reformed Gondwanan continent was not precisely the same as that which had existed before Pangaea formed; for example, most of Florida and southern Georgia and Alabama is underlain by rocks that were originally part of Gondwana, but this region stayed attached to North America when

696-594: A gradual decline during the Triassic while ferns, though never dominant, managed to diversify. The brief period of icehouse conditions during the Triassic–Jurassic extinction event had a dramatic impact on dinosaurs but left plants largely unaffected. The Jurassic was mostly one of hot-house conditions and, while vertebrates managed to diversify in this environment, plants have left little evidence of such development, apart from Cheiroleidiacean conifers and Caytoniales and other groups of seed ferns. In terms of biomass,

812-587: A member of the field team in three summer seasons, 1987–91, who assisted in establishing stream gaging stations on the streams flowing into Lake Fryxell in the 1990–91 season. [REDACTED]  This article incorporates public domain material from websites or documents of the United States Geological Survey . This McMurdo Dry Valleys location article is a stub . You can help Misplaced Pages by expanding it . Gondwana Gondwana ( / ɡ ɒ n d ˈ w ɑː n ə / )

928-480: A much older supercontinent, Rodinia , to amalgamate. One of those orogenic belts, the Mozambique Belt , formed 800 to 650 Ma and was originally interpreted as the suture between East (India, Madagascar, Antarctica, and Australia) and West Gondwana (Africa and South America). Three orogenies were recognised during the 1990s as a result of data sets compiled on behalf of oil and mining companies:

1044-518: A north-east motion about 90 million years ago. While subduction direction changed, it remained oblique (and not perpendicular) to the coast of South America, and the direction change affected several subduction zone -parallel faults including Atacama , Domeyko and Liquiñe-Ofqui . Insular India began to collide with Asia circa 70 Ma , forming the Indian subcontinent , since which more than 1,400 km (870 mi) of crust has been absorbed by

1160-639: A number of species related to those of the laurissilva of Valdivia, through the connection of the Antarctic flora . These include gymnosperms and the deciduous species of Nothofagus , as well as the New Zealand laurel, Corynocarpus laevigatus , and Laurelia novae-zelandiae . New Caledonia and New Zealand became separated from Australia by continental drift 85 million years ago. The islands still retain plants that originated in Gondwana and spread to

1276-544: A pattern that reflects the Jurassic break-up of Pangaea. The Cretaceous saw the arrival of the angiosperms , or flowering plants, a group that probably evolved in western Gondwana (South America–Africa). From there the angiosperms diversified in two stages: the monocots and magnoliids evolved in the Early Cretaceous, followed by the hammamelid dicots . By the Mid-Cretaceous, angiosperms constituted half of

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1392-521: A peak in biodiversity – the end-Permian extinction was enormous and so was the radiation that followed. Two families of conifers, Podocarpaceae and Araucariaceae , dominated Gondwana in the Early Triassic, but Dicroidium , an extinct genus of fork-leaved seed ferns, dominated woodlands and forests of Gondwana during most of the Triassic. Conifers evolved and radiated during the period, with six of eight extant families already present before

1508-853: A series of events severally restricted the Proto-ACC: change to shallow marine conditions along the North Scotia Ridge; closure of the Fuegan Seaway, the deep sea that existed in Tierra del Fuego; and uplift of the Patagonian Cordillera. This, together with the reactivated Iceland plume , contributed to global warming. During the Miocene, the Drake Passage began to widen, and as water flow between South America and

1624-694: A single jaw from Australia. The closure of the Rheic Ocean and the formation of Pangaea in the Carboniferous resulted in the rerouting of ocean currents that initiated an Ice House period. As Gondwana began to rotate clockwise, Australia shifted south to more temperate latitudes. An ice cap initially covered most of southern Africa and South America but spread to eventually cover most of the supercontinent, save for northernmost Africa-South America and eastern Australia. Giant lycopod and horsetail forests continued to evolve in tropical Laurasia together with

1740-719: A southeast direction and enters the north side of Taylor Valley immediately west of Mount Coleman . Charted and named by the BrAE under Scott, 1910-13. Named for the Commonwealth of Australia, which made a financial grant to the BrAE and contributed two members to the Western Geological Party which explored this area. 77°36′S 163°16′E  /  77.600°S 163.267°E  / -77.600; 163.267 . A glacial meltwater stream, 1 nautical mile (1.9 km; 1.2 mi) long, flowing southwest from

1856-661: Is an ice-free valley about 18 nautical miles (33 km; 21 mi) long, once occupied by the receding Taylor Glacier . It lies north of the Kukri Hills between the Taylor Glacier and New Harbour in Victoria Land , Antarctica. Taylor Valley is the southernmost of the three large McMurdo Dry Valleys in the Transantarctic Mountains , located west of McMurdo Sound . The Taylor Valley

1972-742: Is now the Transantarctic Mountains ): the Antarctic Peninsula , Marie Byrd Land , Zealandia , and Thurston Island ; the Falkland Islands and Ellsworth–Whitmore Mountains (in Antarctica) were rotated 90° in opposite directions; and South America south of the Gastre Fault (often referred to as Patagonia ) was pushed westward. The history of the Africa-Antarctica break-up can be studied in great detail in

2088-576: Is now the southern Weddell Sea where initial break-up occurred during the Jurassic c. 180 to 160 Ma . Gondwana began to break up in the early Jurassic following the extensive and fast emplacement of the Karoo-Ferrar flood basalts c. 184 Ma . Before the Karoo plume initiated rifting between Africa and Antarctica , it separated a series of smaller continental blocks from Gondwana's southern, Proto-Pacific margin (along what

2204-679: Is one of the McMurdo Dry Valleys . Parts of the area were visited by British expeditions led by Captain Robert Falcon Scott (1901–04 and 1910–13), who referred to Taylor Valley, as well as Beacon Valley and Pyramid Trough (named later), as "dry valleys." It runs from the east end of Taylor Glacier to New Harbour in McMurdo Sound . It separates the Kukri Hills to the south from the Asgard Range to

2320-541: Is presumed to have been linked to the subduction of cold oceanic lithosphere . During the mid to Late Cretaceous ( c.  90 million years ago ), the Andean orogeny changed significantly in character. Warmer and younger oceanic lithosphere is believed to have started to be subducted beneath South America around this time. Such kind of subduction is held responsible not only for the intense contractional deformation that different lithologies were subject to, but also

2436-787: The Antarctic Peninsula increased, the renewed ACC resulted in cooler global climate. Since the Eocene, the northward movement of the Australian Plate has resulted in an arc-continent collision with the Philippine and Caroline plates and the uplift of the New Guinea Highlands . From the Oligocene to the late Miocene, the climate in Australia, dominated by warm and humid rainforests before this collision, began to alternate between open forest and rainforest before

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2552-886: The Antongil Block in far eastern Madagascar, the Seychelles , and the Napier and Rayner Complexes in East Antarctica ). The Azania continent (much of central Madagascar , the Horn of Africa and parts of Yemen and Arabia) was an island in the Mozambique Ocean. The continent Australia/ Mawson was still separated from India, eastern Africa, and Kalahari by c. 600 Ma , when most of western Gondwana had already been amalgamated. By c. 550 Ma, India had reached its Gondwanan position, which initiated

2668-1075: The Australian Plate are now separated by the Capricorn Plate and its diffuse boundaries. During the opening of the Indian Ocean, the Kerguelen hotspot first formed the Kerguelen Plateau on the Antarctic Plate c. 118 to 95 Ma and then the Ninety East Ridge on the Indian Plate at c. 100 Ma . The Kerguelen Plateau and the Broken Ridge , the southern end of the Ninety East Ridge, are now separated by

2784-844: The Campbell Plateau , Chatham Rise , Lord Howe Rise , Norfolk Ridge , and New Caledonia , from West Antarctica c. 84 Ma . The opening of the South Atlantic Ocean divided West Gondwana (South America and Africa), but there is considerable debate over the exact timing of this break-up. Rifting propagated from south to north along Triassic–Early Jurassic lineaments, but intra-continental rifts also began to develop within both continents in Jurassic–Cretaceous sedimentary basins, subdividing each continent into three sub-plates. Rifting began c. 190 Ma at Falkland latitudes, forcing Patagonia to move relative to

2900-602: The Central Atlantic opened . Antarctica, the centre of the supercontinent, shared boundaries with all other Gondwana continents and the fragmentation of Gondwana propagated clockwise around it. The break-up was the result of the eruption of the Karoo-Ferrar igneous province , one of the Earth's most extensive large igneous provinces (LIP) c. 200 to 170 Ma , but the oldest magnetic anomalies between South America, Africa, and Antarctica are found in what

3016-834: The Drake Passage and the deepening of the Tasman Gateway. The oldest oceanic crust in the Drake Passage, however, is 34 to 29 Ma -old which indicates that the spreading between the Antarctic and South American plates began near the Eocene/Oligocene boundary. Deep sea environments in Tierra del Fuego and the North Scotia Ridge during the Eocene and Oligocene indicate a "Proto-ACC" opened during this period. Later, 26 to 14 Ma ,

3132-598: The East African Orogeny ( 650 to 800 Ma ) and Kuunga orogeny (including the Malagasy Orogeny in southern Madagascar) ( 550 Ma ), the collision between East Gondwana and East Africa in two steps, and the Brasiliano orogeny ( 660 to 530 Ma ), the successive collision between South American and African cratons . The last stages of Gondwanan assembly overlapped with

3248-558: The East African Orogeny , the collision of India and Madagascar with East Africa, and culminating in c.   600 to 530 Ma with the overlapping Brasiliano and Kuunga orogenies, the collision of South America with Africa, and the addition of Australia and Antarctica, respectively. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of some 100,000,000 km (39,000,000 sq mi), about one-fifth of

3364-757: The Great American Interchange . The break-up of Gondwana can be said to continue in eastern Africa at the Afar Triple Junction , which separates the Arabian , Nubian , and Somali plates, resulting in rifting in the Red Sea and East African Rift . In the Early Cenozoic , Australia was still connected to Antarctica c. 35–40° south of its current location and both continents were largely unglaciated. A rift between

3480-803: The Himalayan - Tibetan orogen. During the Cenozoic, the orogen resulted in the construction of the Tibetan Plateau between the Tethyan Himalayas in the south and the Kunlun and Qilian mountains in the north. Later, South America was connected to North America via the Isthmus of Panama , cutting off a circulation of warm water and thereby making the Arctic colder, as well as allowing

3596-845: The Ordovician . This is the Cuyania or Precordillera terrane of the Famatinian orogeny in northwest Argentina which may have continued the line of the Appalachians southwards. Chilenia terrane accreted later against Cuyania. The collision of the Patagonian terrane with the southwestern Gondwanan occurred in the late Paleozoic. Subduction-related igneous rocks from beneath the North Patagonian Massif have been dated at 320–330 million years old, indicating that

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3712-456: The Paleogene (from around 66 to 23 million years ago (Ma)). Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica , Laurentia , and Siberia were separated from it. To differentiate it from the Indian region of the same name (see § Name ), it is also commonly called Gondwanaland . Regions that were part of Gondwana shared floral and zoological elements that persist to

3828-481: The Pangaea supercontinent during the Carboniferous. Pangaea began to break up in the Mid-Jurassic when the Central Atlantic opened . In the western end of Pangaea, the collision between Gondwana and Laurasia closed the Rheic and Palaeo-Tethys oceans. The obliquity of this closure resulted in the docking of some northern terranes in the Marathon , Ouachita , Alleghanian , and Variscan orogenies, respectively. Southern terranes, such as Chortis and Oaxaca , on

3944-499: The Southeast Indian Ridge . Separation between Australia and East Antarctica began c. 132 Ma with seafloor spreading occurring c. 96 Ma . A shallow seaway developed over the South Tasman Rise during the Early Cenozoic and as oceanic crust started to separate the continents during the Eocene c. 35.5 Ma global ocean temperature dropped significantly. A dramatic shift from arc- to rift magmatism c. 100 Ma separated Zealandia , including New Zealand ,

4060-442: The Uralian orogeny and Laurasia . Pangaea was finally amalgamated in the Late Carboniferous-Early Permian, but the oblique forces continued until Pangaea began to rift in the Triassic. In the eastern end, collisions occurred slightly later. The North China , South China , and Indochina blocks rifted from Gondwana during the middle Paleozoic and opened the Proto-Tethys Ocean . North China docked with Mongolia and Siberia during

4176-422: The Variscan orogeny close to the Carboniferous–Permian boundary. South-east Asia was made of Gondwanan and Cathaysian continental fragments that were assembled during the Mid-Palaeozoic and Cenozoic. This process can be divided into three phases of rifting along Gondwana's northern margin: first, in the Devonian, North and South China , together with Tarim and Quidam (north-western China) rifted, opening

4292-403: The uplift and erosion known to have occurred from the Late Cretaceous onward. Plate tectonic reorganisation since the mid-Cretaceous might also have been linked to the opening of the South Atlantic Ocean . Another change related to mid-Cretaceous plate tectonic rearrangement was the change of subduction direction of the oceanic lithosphere that went from having south-east motion to having

4408-446: The 1990-91 season. 77°37′S 163°03′E  /  77.617°S 163.050°E  / -77.617; 163.050 . A glacial meltwater stream, 0.5 nautical miles (0.93 km; 0.58 mi) long, which flows from the snout of Canada Glacier. It drains NE, close to the glacier, entering the west end of Lake Fryxell to the west of Bowles Creek and Green Creek. The name was suggested by Diane McKnight, USGS hydrologist working in

4524-437: The 8th Victoria University of Wellington Antarctic Expedition (VUWAE), 1963–64, for physicist R.A. Hoare, a member of VUWAE that examined lakes in Taylor, Wright, and Victoria Valleys. 77°37′S 163°11′E  /  77.617°S 163.183°E  / -77.617; 163.183 . Lake 3 nautical miles (5.6 km; 3.5 mi) long, between Canada and Commonwealth Glaciers at the lower end of Taylor Valley. Mapped by

4640-472: The BrAE under Scott, 1910-13. The lake was visited by Professor T.L. Péwé during United States Navy Operation Deep Freeze , 1957–58, and was named by him for Doctor Fritiof M. Fryxell, glacial geologist of Augustana College, Illinois. 77°36′S 163°19′E  /  77.600°S 163.317°E  / -77.600; 163.317 . A pond, 0.3 nautical miles (0.56 km; 0.35 mi) long, located 0.5 nautical miles (0.93 km; 0.58 mi) south of

4756-410: The BrAE under Scott, 1910–13, for Professor Eduard Suess, noted Austrian geologist and paleontologist. 77°37′S 162°59′E  /  77.617°S 162.983°E  / -77.617; 162.983 . Small glacier flowing southeast into the north side of Taylor Valley immediately west of Lake Fryxell. Charted and named by the BrAE, 1910–13, under Scott. Charles S. Wright, a Canadian physicist,

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4872-502: The Carboniferous–Permian, followed by South China. The Cimmerian blocks then rifted from Gondwana to form the Palaeo-Thethys and Neo-Tethys oceans in the Late Carboniferous, and docked with Asia during the Triassic and Jurassic. Western Pangaea began to rift while the eastern end was still being assembled. The formation of Pangaea and its mountains had a tremendous impact on global climate and sea levels, which resulted in glaciations and continent-wide sedimentation. In North America,

4988-405: The Early Cretaceous, and West Burma and Woyla during the Late Cretaceous. Gondwana's long, northern margin remained a mostly passive margin throughout the Palaeozoic. The Early Permian opening of the Neo-Tethys Ocean along this margin produced a long series of terranes, many of which were and still are being deformed in the Himalaya Orogeny . These terranes are, from Turkey to north-eastern India:

5104-403: The Earth's surface. It fused with Euramerica during the Carboniferous to form Pangea . It began to separate from northern Pangea ( Laurasia ) during the Triassic , and started to fragment during the Early Jurassic (around 180 million years ago). The final stages of break-up, involving the separation of Antarctica from South America (forming the Drake Passage ) and Australia, occurred during

5220-448: The Equator during this period and remained a lifeless and barren landscape. West Gondwana drifted north during the Devonian , bringing Gondwana and Laurasia close together. Global cooling contributed to the Late Devonian extinction (19% of marine families and 50% of genera went extinct) and glaciation occurred in South America. Before Pangaea had formed, terrestrial plants, such as pteridophytes , began to diversify rapidly resulting in

5336-400: The Equator on landmasses then limited to Laurasia and, in Gondwana, to Australia. In the late Silurian, two distinctive lineages, zosterophylls and rhyniophytes , had colonised the tropics. The former evolved into the lycopods that were to dominate the Gondwanan vegetation over a long period, whilst the latter evolved into horsetails and gymnosperms . Most of Gondwana was located far from

5452-446: The Jurassic flora was dominated by conifer families and other gymnosperms that had evolved during the Triassic. The Pteridophytes that had dominated during the Palaeozoic were now marginalised, except for ferns. In contrast to Laurentia, very few insect fossils have been found in Gondwana, to a considerable extent because of widespread deserts and volcanism. While plants had a cosmopolitan distribution, dinosaurs evolved and diversified in

5568-406: The Kuunga orogeny (also known as the Pinjarra orogeny). Meanwhile, on the other side of the newly forming Africa, Kalahari collided with Congo and Rio de la Plata which closed the Adamastor Ocean . c. 540–530 Ma, the closure of the Mozambique Ocean brought India next to Australia–East Antarctica, and both North and South China were in proximity to Australia. As the rest of Gondwana formed,

5684-564: The Lake Fryxell basin, 1987–94, and alludes to the many aeolian deposits of fine sands along the creek, indicative of strong winds blowing around the south end of Canada Glacier during the winter. Named from "They Called the Wind Maria," a song in Paint Your Wagon, the American musical play by Lerner and Loewe. 77°37′S 163°03′E  /  77.617°S 163.050°E  / -77.617; 163.050 . A glacial meltwater distributary stream, 0.25 nautical miles (0.46 km; 0.29 mi) long, which flows east from Maria Creek (q.v.) into

5800-422: The Late Permian, many known from South Africa and Australia. Beetles and cockroaches remained minor elements in this fauna. Tetrapod fossils from the Early Permian have only been found in Laurasia but they became common in Gondwana later during the Permian. The arrival of the therapsids resulted in the first plant-vertebrate-insect ecosystem. During the Mid- to Late Triassic, hot-house conditions coincided with

5916-405: The Miocene, a warm and humid climate developed with pockets of rainforests in central Australia, but before the end of the period, colder and drier climate severely reduced this rainforest. A brief period of increased rainfall in the Pliocene was followed by drier climate which favoured grassland. Since then, the fluctuation between wet interglacial periods and dry glacial periods has developed into

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6032-443: The Neoproterozoic to Palaeozoic phase of the Terra Australis Orogen , a series of terranes were rafted from the proto-Andean margin when the Iapteus Ocean opened, to be added back to Gondwana during the closure of that ocean. During the Paleozoic, some blocks which helped to form parts of the Southern Cone of South America, include a piece transferred from Laurentia when the west edge of Gondwana scraped against southeast Laurentia in

6148-516: The New Zealand Geographic Board (NZGB) in 1998. Parera is the Maori word for wild duck. 77°40′S 162°39′E  /  77.667°S 162.650°E  / -77.667; 162.650 . A pond between Suess and Lacroix Glaciers. So named by T.L. Péwé, United States geologist who visited the area in December 1957, because of the mummified seals found around the pond. 77°38′S 162°46′E  /  77.633°S 162.767°E  / -77.633; 162.767 . Small lake lying east of

6264-441: The Palaeo-Tethys behind them. These terranes accreted to Asia during Late Devonian and Permian. Second, in the Late Carboniferous to Early Permian, Cimmerian terranes opened Meso-Tethys Ocean; Sibumasu and Qiangtang were added to south-east Asia during Late Permian and Early Jurassic. Third, in the Late Triassic to Late Jurassic, Lhasa , West Burma , Woyla terranes opened the Neo-Tethys Ocean; Lhasa collided with Asia during

6380-456: The South Atlantic (Brazil and Cameroon ) dating to around 120  million years ago , suggesting that some form of land connection still existed between Africa and South America as recently as the early Aptian . The first phases of Andean orogeny in the Jurassic and Early Cretaceous were characterised by extensional tectonics , rifting , the development of back-arc basins and the emplacement of large batholiths . This development

6496-465: The Southern Hemisphere, has a "Gondwanan distribution" and is often described as an archaic, or relict , lineage. The distributions in the Proteaceae is, nevertheless, the result of both Gondwanan rafting and later oceanic dispersal. During the Silurian, Gondwana extended from the Equator (Australia) to the South Pole (North Africa and South America) whilst Laurasia was located on the Equator opposite to Australia. A short-lived Late Ordovician glaciation

6612-408: The Taurides in southern Turkey; the Lesser Caucasus Terrane in Georgia; the Sanand, Alborz, and Lut terranes in Iran; the Mangysglak or Kopetdag Terrane in the Caspian Sea; the Afghan Terrane; the Karakorum Terrane in northern Pakistan; and the Lhasa and Qiangtang terranes in Tibet. The Permian–Triassic widening of the Neo-Tethys pushed all these terranes across the Equator and over to Eurasia. During

6728-447: The Western Journey Party, led by Griffith Taylor, of the BrAE, 1910-13. 77°41′S 162°15′E  /  77.683°S 162.250°E  / -77.683; 162.250 . A prominent hump-shaped peak along the north wall of Taylor Valley, standing above Lake Bonney, between Rhone Glacier and Matterhorn Glacier. So named by the Western Journey Party, led by Taylor, of the BrAE, 1910-13. The initials have been retained to distinguish

6844-538: The amounts in Arctic air as compared to values observed at lower latitudes. This unexpected phenomenon, width implications for later ozone depletion studies, became known as the "Noxon cliff". In 1978, Noxon sailed on RV Hero from Ushuaia, and quickly confirmed that a "cliff" in nitrogen dioxide is also found in the Antarctic atmosphere. 77°31′48″S 163°09′12″E  /  77.529981°S 163.153205°E  / -77.529981; 163.153205 A rounded rock summit rising to about 900 metres (3,000 ft) high in

6960-528: The area in December 1957. 77°40′S 162°33′E  /  77.667°S 162.550°E  / -77.667; 162.550 . Glacier between Suess and Matterhorn Glaciers, which flows southeast into Taylor Valley. Mapped by the BrAE under Scott, 1910–13, and named after Alfred Lacroix (see Mount Lacroix ). 77°38′S 162°40′E  /  77.633°S 162.667°E  / -77.633; 162.667 . Glacier between Canada and Lacroix Glaciers, flowing south into Taylor Valley. Charted and named by

7076-455: The axis of Taylor Valley, forming a divide 100 metres (330 ft) above sea level between Lake Fryxell and Explorers Cove, McMurdo Sound. A large number of solitary fossil corals have been found here by NZARP/USARP teams in the course of joint geological studies of the area. The name was suggested by Donald P. Elston, USGS, a research team member who worked at the ridge in the 1979–80 and 1980-81 seasons. Glaciers and streams descending towards

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7192-550: The base of the Absaroka sequence coincides with the Alleghanian and Ouachita orogenies and are indicative of a large-scale change in the mode of deposition far away from the Pangaean orogenies. Ultimately, these changes contributed to the Permian–Triassic extinction event and left large deposits of hydrocarbons, coal, evaporite, and metals. The breakup of Pangaea began with the Central Atlantic magmatic province (CAMP) between South America, Africa, North America, and Europe. CAMP covered more than seven million square kilometres over

7308-557: The bottom of a shallow sea between 250 million and 400 million years ago. Throughout that period, Earth's southern continents were locked into the supercontinent Gondwana . The dark band of rock that divides the sandstone is dolerite (sometimes called diabase), a volcanic rock that forms underground. The distinctive dolerite intrusion—or sill —is a remnant of a massive volcanic plumbing system that produced major eruptions about 180 million years ago. The eruptions likely helped tear Gondwana apart. Download coordinates as: Taylor Valley

7424-404: The camp area. A mummified seal is prominent at the mouth of the stream. 77°35′S 163°30′E  /  77.583°S 163.500°E  / -77.583; 163.500 . A meltwater stream in Taylor Valley which flows east from Commonwealth Glacier into New Harbor of McMurdo Sound. Studied on the ground during United States Navy Operation Depp Freeze, 1957–58, by Troy L. Péwé who suggested

7540-414: The colonisation of Gondwana. The Baragwanathia Flora, found only in the Yea Beds of Victoria, Australia, occurs in two strata separated by 1,700 m (5,600 ft) or 30 Ma; the upper assemblage is more diverse and includes Baragwanathia, the first primitive herbaceous lycopod to evolve from the zosterophylls. During the Devonian, giant club mosses replaced the Baragwanathia Flora, introducing

7656-492: The continent Kazakhstania in the late Silurian . Whether these blocks originated on the shores of Gondwana is not known. In the Early Palaeozoic, the Armorican terrane , which today form large parts of France, was part of either Peri-Gondwana or core Gondwana; the Rheic Ocean closed in front of it and the Palaeo-Tethys Ocean opened behind it. Precambrian rocks from the Iberian Peninsula suggest that it, too, formed part of core Gondwana before its detachment as an orocline in

7772-424: The continent became the arid or semiarid landscape it is today. The adjective "Gondwanan" is in common use in biogeography when referring to patterns of distribution of living organisms, typically when the organisms are restricted to two or more of the now-discontinuous regions that were once part of Gondwana, including the Antarctic flora . For example, the plant family Proteaceae , known from all continents in

7888-559: The development of rifts systems on both continents, including the Central African Rift System and the Central African Shear Zone which lasted until c. 85 Ma . At Brazilian latitudes spreading is more difficult to assess because of the lack of palaeo-magnetic data, but rifting occurred in Nigeria at the Benue Trough c. 118 Ma . North of the Equator the rifting began after 120.4 Ma and continued until c. 100 to 96 Ma . Dinosaur footprints representing identical species assemblages are known from opposite sides of

8004-598: The east part of Noxon Cliff. Dominion Hill bounds the north edge of Commonwealth Glacier where it descends southeastward into Taylor Valley . Named by New Zealand Geographic Board (NZGB) (1998) after a form of government to complement the Commonwealth (of Australia) Glacier. [REDACTED]  This article incorporates public domain material from websites or documents of the United States Geological Survey . Commonwealth Glacier Taylor Valley 77°37′S 163°00′E  /  77.617°S 163.000°E  / -77.617; 163.000  ( Taylor Valley )

8120-437: The end of it. Bennettitales and Pentoxylales , two now extinct orders of gymnospermous plants, evolved in the Late Triassic and became important in the Jurassic and Cretaceous. It is possible that gymnosperm biodiversity surpassed later angiosperm biodiversity and that the evolution of angiosperms began during the Triassic but, if so, in Laurasia rather than in Gondwana. Two Gondwanan classes, lycophytes and sphenophytes , saw

8236-650: The eruption of the Deccan basalts , whose eruption site may survive as the Réunion hotspot . The Seychelles and the Maldives are now separated by the Central Indian Ridge . During the initial break-up in the Early Jurassic a marine transgression swept over the Horn of Africa covering Triassic planation surfaces with sandstone , limestone , shale , marls and evaporites . East Gondwana, comprising Antarctica, Madagascar, India, and Australia, began to separate from Africa. East Gondwana then began to break up c. 132.5 to 96 Ma when India moved northwest from Australia-Antarctica. The Indian Plate and

8352-563: The evolution of Voltziales , one of the few plant orders to survive the end-Permian extinction (57% of marine families and 83% of genera went extinct) and which came to dominate in the Late Permian and from whom true conifers evolved. Tall lycopods and horsetails dominated the wetlands of Gondwana in the Early Permian. Insects co-evolved with glossopterids across Gondwana and diversified with more than 200 species in 21 orders by

8468-564: The first amniote reptilians evolved, all closely related to the Laurasian fauna, but spreading ice eventually drove these animals away from Gondwana entirely. The Gondwana ice sheet melted, and sea levels dropped during the Permian and Triassic global warming. During this period, the extinct glossopterids colonised Gondwana and reached peak diversity in the Late Permian when coal-forming forests covered much of Gondwana. The period also saw

8584-522: The first trees, and by the Late Devonian this first forest was accompanied by the progymnosperms , including the first large trees Archaeopteris . The Late Devonian extinction probably also resulted in osteolepiform fishes evolving into the amphibian tetrapods , the earliest land vertebrates, in Greenland and Russia. The only traces of this evolution in Gondwana are amphibian footprints and

8700-526: The flora in northeastern Australia. There is, however, no obvious connection between this spectacular angiosperm radiation and any known extinction event nor with vertebrate/insect evolution. Insect orders associated with pollination, such as beetles , flies , butterflies and moths , and wasps, bees, and ants , radiated continuously from the Permian-Triassic, long before the arrival of the angiosperms. Well-preserved insect fossils have been found in

8816-636: The fracture zones and magnetic anomalies flanking the Southwest Indian Ridge . The Madagascar block and the Mascarene Plateau , stretching from the Seychelles to Réunion , were broken off India, causing Madagascar and Insular India to be separate landmasses : elements of this break-up nearly coincide with the Cretaceous–Paleogene extinction event . The India–Madagascar–Seychelles separations appear to coincide with

8932-579: The front of Canada Glacier into Lake Fryxell, in Taylor Valley. Named in association with Canada Glacier by the New Zealand Antarctic Place-Names Committee (NZ-APC) in 1983. 77°37′S 163°03′E  /  77.617°S 163.050°E  / -77.617; 163.050 . A glacial meltwater stream which flows south along the east margin of Canada Glacier into the west end of Lake Fryxell. The name

9048-508: The ground by Troy L. Péwé during United States Navy OpDFrz, 1957–58, and so named by him because the stream has a series of deltas along its length which have been cut through as the stream was rejuvenated, the rejuvenation being caused by the lowering of the former glacial lake. 77°37′S 163°11′E  /  77.617°S 163.183°E  / -77.617; 163.183 . A glacial meltwater stream, 2.6 nautical miles (4.8 km; 3.0 mi) long, flowing north from Crescent Glacier to

9164-516: The hydrology and geochemistry of streams and ponds in the Lake Fryxell basin, Taylor Valley, 1987-94. Named after USGS hydrologist Sarah Ann Spauiding, a member of the team during two seasons, 1988–89 and 1991–92, who studied the pond. 77°38′S 162°51′E  /  77.633°S 162.850°E  / -77.633; 162.850 . A lake about 2 nautical miles (3.7 km; 2.3 mi) long between Lake Chad and Canada Glacier. Named by

9280-481: The hydrology of streams of the Lake Fryxell basin, 1987-94. Named after William J. Green of Miami University, Oxford, Ohio, who conducted research on the geochemistry of the Onyx River, 1980–81, and Lake Fryxell, Lake Hoare, and their feeder streams, 1982-83. 77°37′S 163°03′E  /  77.617°S 163.050°E  / -77.617; 163.050 . A small meltwater stream flowing east-southeast from

9396-861: The lake deposits of the Santana Formation in Brazil, the Koonwarra Lake fauna in Australia, and the Orapa diamond mine in Botswana. Dinosaurs continued to prosper but, as the angiosperm diversified, conifers, bennettitaleans and pentoxylaleans disappeared from Gondwana c. 115 Ma together with the specialised herbivorous ornithischians , whilst generalist browsers, such as several families of sauropodomorph Saurischia , prevailed. The Cretaceous–Paleogene extinction event killed off all dinosaurs except birds, but plant evolution in Gondwana

9512-516: The mouth of Suess Glacier. Charted and named by the BrAE under Scott, 1910–13, after the African lake of the same name. 77°39′S 163°07′E  /  77.650°S 163.117°E  / -77.650; 163.117 . A pond 0.3 nautical miles (0.56 km; 0.35 mi) northeast of the terminal ice cliff of Howard Glacier. The name was suggested by Diane McKnight , leader of United States Geological Survey (USGS) field teams which studied

9628-698: The name from Mount Allan Thomson (also named by BrAE, 1910–13) near Mackay Glacier. 77°43′S 162°25′E  /  77.717°S 162.417°E  / -77.717; 162.417 . Lake lying at the mouth of Taylor Glacier. Visited by the BrnAE, 1901-04. Named by the BrAE under Scott, 1910–13, for T. Bonney, professor of geology at Cambridge University, England. 77°42′S 162°35′E  /  77.700°S 162.583°E  / -77.700; 162.583 . Minor knobs, 3 to 6 metres (9.8 to 19.7 ft) high, composed of lake clay covered by glacial drift. The glacial drift has cobbles that are well polished by

9744-894: The name in association with Commonwealth Glacier. Glaciers descending towards the valley floor from the Kukri Hills include, from west to east, Glaciers in the Kukri Hills that flow towards the Taylor Valley floor include, from west to east, Calkin Glacier , Hughes Glacier , Sollas Glacier , Marr Glacier , Moa Glacier , Goldman Glacier , Howard Glacier , Crescent Glacier , Von Guerard Glacier . Aiken Glacier and Wales Glacier . Meltwater streams include: 77°39′S 163°07′E  /  77.650°S 163.117°E  / -77.650; 163.117 . A glacial meltwater tributary stream, 1.6 nautical miles (3.0 km; 1.8 mi) long, flowing north from Howard Glacier into Delta Stream. Spaulding Pond lies along this watercourse. The name

9860-442: The north flank of Commonwealth Glacier where it rises from 50 to 150 metres (160 to 490 ft) high above the glacier. Named by US-ACAN (1997) after John F. Noxon, who pioneered the technique of visible spectroscopy for measurements of stratospheric trace gases, particularly nitrogen dioxide. By 1975, he began making measurements of nitrogen dioxide column as a function of latitude, and was surprised to discover an abrupt decrease in

9976-540: The north-central shore of Lake Fryxell. The name was suggested by hydrologist Diane McKnight, leader of a USGS team that made extensive hydrological studies in the Lake Fryxell basin, 1987-94. The name acknowledges support received by the USGS field team in Taylor Valley from United States Navy Squadron VXE-6 and its twin engine UH-1N "Huey" helicopters. 77°35′S 163°19′E  /  77.583°S 163.317°E  / -77.583; 163.317 . Glacier which flows in

10092-548: The north. Features of the valley include, from west to east, Bonney Riegel below Mount J. J. Thomson, Lake Bonney, Nussbaum Reigel, Mummy Pond, Lake Chad, Andrews Ridge and Lake Frysell, which is fed by the Delta Stream from the south. 77°43′S 162°22′E  /  77.717°S 162.367°E  / -77.717; 162.367 . A riegel , or rock bar extending north from the Kukri Hills across Taylor Valley to Lake Bonney. Named in association with Lake Bonney by

10208-494: The northern arm of Nussbaum Riegel, which trends eastward to the south of Suess Glacier and Lake Chad in Taylor Valley. Named by Griffith Taylor, leader of the Western Journey Party of the BrAE, 1910-13. 77°39′15″S 162°55′02″E  /  77.654241°S 162.917318°E  / -77.654241; 162.917318 . A pond lying 1 nautical mile (1.9 km; 1.2 mi) south of Andrews Ridge. Named by

10324-701: The opening of the Iapetus Ocean between Laurentia and western Gondwana. During this interval, the Cambrian explosion occurred. Laurentia was docked against the western shores of a united Gondwana for a brief period near the Precambrian/Cambrian boundary, forming the short-lived and still disputed supercontinent Pannotia . The Mozambique Ocean separated the Congo – Tanzania – Bangweulu Block of central Africa from Neoproterozoic India (India,

10440-600: The other hand, remained largely unaffected by the collision along the southern shores of Laurentia. Some Peri-Gondwanan terranes, such as Yucatán and Florida , were buffered from collisions by major promontories. Other terranes, such as Carolina and Meguma , were directly involved in the collision. The final collision resulted in the Variscan- Appalachian Mountains , stretching from present-day Mexico to southern Europe. Meanwhile, Baltica collided with Siberia and Kazakhstania which resulted in

10556-561: The present arid regime. Australia has thus experienced various climate changes over a 15-million-year period with a gradual decrease in precipitation. The Tasman Gateway between Australia and Antarctica began to open c. 40 to 30 Ma . Palaeontological evidence indicates the Antarctic Circumpolar Current (ACC) was established in the Late Oligocene c. 23 Ma with the full opening of

10672-530: The present day. The continent of Gondwana was named by the Austrian scientist Eduard Suess , after the region in central India of the same name , which is derived from Sanskrit for "forest of the Gonds ". The name had been previously used in a geological context, first by H. B. Medlicott in 1872, from which the Gondwana sedimentary sequences ( Permian - Triassic ) are also described. Some scientists prefer

10788-760: The remaining Gondwana c. 570 to 530 Ma in the Kuunga Orogeny. The later Malagasy orogeny at about 550–515 Mya affected Madagascar, eastern East Africa and southern India. In it, Neoproterozoic India collided with the already combined Azania and Congo–Tanzania–Bangweulu Block, suturing along the Mozambique Belt. The 18,000 km-long (11,000 mi) Terra Australis Orogen developed along Gondwana's western, southern, and eastern margins. Proto-Gondwanan Cambrian arc belts from this margin have been found in eastern Australia, Tasmania, New Zealand, and Antarctica. Though these belts formed

10904-602: The snout of Commonwealth Glacier and entering the east end of Lake Fryxell between Lost Seal Stream and Aiken Creek. Named by the US-ACAN after Diane McKnight, research hydrologist, USGS, leader of USGS field teams over several years (1987–94) that made extensive studies of the hydrology and geochemistry of streams flowing into Lake Fryxell. 77°36′S 163°14′E  /  77.600°S 163.233°E  / -77.600; 163.233 . A glacial meltwater stream, 1.4 nautical miles (2.6 km; 1.6 mi) long, draining from

11020-608: The snout of Commonwealth Glacier in Taylor Valley. The pond is part of the Aiken Creek system and receives drainage from several glaciers including Commonwealth Glacier, Wales Glacier and the unnamed glacier next westward. The name was suggested by USGS hydrologist Diane McKnight, leader of USGS field teams that studied the hydrology of streams entering Lake Fryxell, Taylor Valley, 1987-94. 77°35′S 163°25′E  /  77.583°S 163.417°E  / -77.583; 163.417 . A ridge trending north–south, transverse to

11136-450: The south-central shore of Lake Fryxell. Named in association with Crescent Glacier. The name was suggested by USGS hydrologist Diane McKnight and was approved by the US-ACAN and the NZGB in 1994. 77°37′S 163°13′E  /  77.617°S 163.217°E  / -77.617; 163.217 . A meltwater stream, 3 nautical miles (5.6 km; 3.5 mi) long, which flows north from

11252-625: The southwest end of Lake Fryxell, close west of Green Creek. The name was suggested by hydrologist Diane McKnight, leader of a USGS team which made extensive studies of the hydrology and geochemistry of streams and ponds in the Lake Fryxell basin, 1987-94. Named after USGS hydrologist Elizabeth C. Bowles, a member of the field team in the 1987-88 summer season, who conducted a study of organic geochemistry of streams flowing into Lake Fryxell. 77°36′S 163°17′E  /  77.600°S 163.283°E  / -77.600; 163.283 . A glacial meltwater stream in Taylor Valley, which flows north from

11368-665: The still static remainder of South America and Africa, and this westward movement lasted until the Early Cretaceous 126.7 Ma . From there rifting propagated northward during the Late Jurassic c. 150 Ma or Early Cretaceous c. 140 Ma most likely forcing dextral movements between sub-plates on either side. South of the Walvis Ridge and Rio Grande Rise the Paraná and Etendeka magmatics resulted in further ocean-floor spreading c. 130 to 135 Ma and

11484-399: The subduction process initiated in the early Carboniferous. This was relatively short-lived (lasting about 20 million years), and initial contact of the two landmasses occurred in the mid-Carboniferous, with broader collision during the early Permian. In the Devonian, an island arc named Chaitenia accreted to Patagonia in what is now south-central Chile. Gondwana and Laurasia formed

11600-525: The term "Gondwanaland" for the supercontinent to make a clear distinction between the region and the supercontinent. The assembly of Gondwana was a protracted process during the Neoproterozoic and Paleozoic , which remains incompletely understood because of the lack of paleo-magnetic data. Several orogenies , collectively known as the Pan-African orogeny , caused the continental fragments of

11716-636: The two developed but remained an embayment until the Eocene-Oligocene boundary when the Circumpolar Current developed and the glaciation of Antarctica began. Australia was warm and wet during the Palaeocene and dominated by rainforest. The opening of the Tasman Gateway at the Eocene-Oligocene boundary ( 33 Ma ) resulted in abrupt cooling but the Oligocene became a period of high rainfall with swamps in southeast Australia. During

11832-711: The unnamed glacier east of Crescent Glacier into the east part of Lake Fryxell. The name was suggested by hydrologist Diane McKnight, leader of a USGS team that made extensive studies of the hydrology and geochemistry of streams and ponds in the Lake Fryxell basin, 1987-94. Named after USGS hydrologist Richard A. Harnish, a member of the field team in the 1988–89 and 1990-91 seasons; during latter season assisted in establishing stream gaging stations on streams flowing into Lake Fryxell. 77°37′S 163°15′E  /  77.617°S 163.250°E  / -77.617; 163.250 . A glacial meltwater stream, 2.5 nautical miles (4.6 km; 2.9 mi) long, which flows northwest from

11948-444: The unnamed glacier east of Crescent Glacier to enter Lake Fryxell close east of Harnish Creek. The name was suggested by Diane McKnight, leader of USGS teams which made extensive studies of the hydrology of streams in the Lake Fryxell basin, 1987-94. Named after hydrologist Paul B. von Guerard, a member of the field team in three seasons, 1990–94, who assisted in establishing stream gaging stations on streams flowing into Lake Fryxell in

12064-455: The unnamed glacier west of Wales Glacier to Many Glaciers Pond, then west to Lake Fryxell. The feature is 4 nautical miles (7.4 km; 4.6 mi) long and receives some tributary flow from Wales Glacier. The name was suggested by hydrologist Diane McKnight, leader of the USGS team which made extensive studies of the hydrology and geochemistry of streams and ponds in the Lake Fryxell basin, 1987-94. Named after USGS hydrologist George R. Aiken,

12180-543: The valley floor from the Asgard Range include Matterhorn Glacier, Lacroix Glacier, Suess Glacier, Canada Glacier and Commonwealth Glacier. 77°41′S 162°27′E  /  77.683°S 162.450°E  / -77.683; 162.450 . Small alpine glacier on the edge of the north wall of Taylor Valley, just west of the Matterhorn. Named after the Matterhorn by United States geologist T.L. Péwé, who visited

12296-529: The vicinity of Sollas Glacier toward Lake Chad. Charted and named by the BrAE under Scott, 1910-13. 77°39′S 162°43′E  /  77.650°S 162.717°E  / -77.650; 162.717 . Narrow ice-free passageway between the terminus of Suess Glacier and the talus-covered slope of Nussbaum Riegel in Taylor Valley. Charted and descriptively named by the BrAE under Scott, 1910-13. 77°39′S 162°50′E  /  77.650°S 162.833°E  / -77.650; 162.833 . A gentle ridge,

12412-441: The west margin of Commonwealth Glacier into the northeast end of Lake Fryxell. The name was suggested by Diane McKnight, leader of a USGS team that studied the hydrology of streams flowing into Lake Fryxell in several seasons, 1987-94. The name commemorates the encounter with a living Weddell seal. The seal wandered into the area north of Lake Fryxell during November 1990 and was evacuated by helicopter to New Harbor after it entered

12528-403: The west side of Flint Ridge. Named descriptively by Advisory Committee on Antarctic Names (US-ACAN) (1997) from the shape of the hill which is suggestive of an arrowhead, or the characteristic leaf form. 77°31′41″S 163°05′07″E  /  77.528156°S 163.085353°E  / -77.528156; 163.085353 An E-W trending cliff at the south end of Flint Ridge. The cliff encloses

12644-469: The wind and cut into ventifacts . The knobs are covered by ventifacts, suggesting the name, and are located just east of Lake Bonney. Named by United States geologist Troy L. Péwé who was first to study and describe the knobs in December 1957. 77°40′S 162°46′E  /  77.667°S 162.767°E  / -77.667; 162.767 . A riegel or rock-bar across Taylor Valley, extending from

12760-499: Was a large landmass, sometimes referred to as a supercontinent . The remnants of Gondwana make up around two-thirds of today's continental area, including South America , Africa , Antarctica , Australia , Zealandia , Arabia , and the Indian Subcontinent . Gondwana was formed by the accretion of several cratons (large stable blocks of the Earth's crust), beginning c.   800 to 650 Ma with

12876-489: Was a member of the party that explored this area. 77°37′S 163°04′E  /  77.617°S 163.067°E  / -77.617; 163.067 . A glacial meltwater stream, 0.65 nautical miles (1.20 km; 0.75 mi) long, flowing northeast from the extremity of Canada Glacier into the southwest end of Lake Fryxell, close east of Bowles Creek, in Taylor Valley. The name was suggested by hydrologist Diane McKnight, leader of USGS teams that made intensive studies of

12992-644: Was discovered by the British National Antarctic Expedition (BrNAE, 1901–04). It was more fully explored by the British Antarctic Expedition, 1907–09 (BrAE) and the British Antarctic Expedition, 1910–13 . It was named after the Taylor Glacier. In the oblique aerial photo at right, the tan bands are sandstone layers from the Beacon Supergroup , a series of sedimentary rock layers formed at

13108-483: Was followed by a Silurian Hot House period. The End-Ordovician extinction , which resulted in 27% of marine invertebrate families and 57% of genera going extinct, occurred during this shift from Ice House to Hot House. By the end of the Ordovician, Cooksonia , a slender, ground-covering plant, became the first known vascular plant to establish itself on land. This first colonisation occurred exclusively around

13224-540: Was hardly affected. Gondwanatheria is an extinct group of non- therian mammals with a Gondwanan distribution (South America, Africa, Madagascar, India, Zealandia and Antarctica) during the Late Cretaceous and Palaeogene. Xenarthra and Afrotheria , two placental clades, are of Gondwanan origin and probably began to evolve separately c. 105 Ma when Africa and South America separated. The laurel forests of Australia, New Caledonia, and New Zealand have

13340-538: Was suggested by Diane McKnight, leader of a USGS team which made extensive studies of the hydrology and geochemistry of streams and ponds in the Lake Fryxell basin, 1987-94. Named after hydrologist Edward Furlong, a member of the field team that established stream gaging stations on streams flowing into Lake Fryxell in the 1990-91 season. 77°38′S 163°07′E  /  77.633°S 163.117°E  / -77.633; 163.117 . Small meltwater stream flowing from Howard Glacier into Lake Fryxell. First studied on

13456-582: Was suggested by hydrologist Diane McKnight, leader of a USGS team which made extensive studies of the hydrology and geochemistry of streams and ponds in the Lake Fryxell basin, 1987-94. Named after USGS hydrologist Edmund Andrews, a member of the field team who studied glacier hydrology during the 1987–88 and 1991-92 summer seasons. 77°36′S 163°06′E  /  77.600°S 163.100°E  / -77.600; 163.100 . A glacial meltwater stream, 1.2 nautical miles (2.2 km; 1.4 mi) long, flowing south from an ice field west of Mount Falconer to

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