The Mawson Formation is a geological formation in Antarctica , dating to roughly between 182 and 177 million years ago and covering the Toarcian stages of the Jurassic Period in the Mesozoic Era . Vertebrate remains are known from the formation. The Mawson Formation is the South Victoria Land equivalent of the Karoo Large Igneous Province in South Africa (including the upper Clarens Formation desertic interbeds), as well the Lonco Trapial Formation and the Cañadón Asfalto Formation of Argentina . The Volcanic material was likely sourced from the Antarctic Peninsula´s Ellsworth Land Volcanic Group .
35-698: The thin lacustrine interbeds of the Mawson Formation have received several names in literature, being known as either Carapace Sandstone or Carapace Formation, being a series of Freshwater environments developed during times when the Kirkpatrick Basalt stopped invading the zone. The lava flow deposits of the Kirkpatrick Basalt belong to the Ferrar Large Igneous Province , developed in a linear belt along
70-504: A mountain range of uplifted rock (primarily sedimentary ) in Antarctica which extends, with some interruptions, across the continent from Cape Adare in northern Victoria Land to Coats Land . These mountains divide East Antarctica and West Antarctica . They include a number of separately named mountain groups, which are often again subdivided into smaller ranges. The range was first sighted by James Clark Ross in 1841 at what
105-419: A deposit of interbeds dominated by sandstones of fluvial to lacustrine origin. The main outcrop of this location is notorious for the presence of a 37 m Hialoclastite , volcanic material accumulated, likely on a local lake of the same depth. This lake layers, called "Lake Carapace", host the only relatively complete fish remains recovered in the whole formation, and was likely feed by seasonal streams that brought
140-440: A paleovalley of up to 500 m was present. In this paleovalleys, massive production and accumulation of volcanic lahars in lowlands occur, in a similar way to more recent ones of places such as Osceola Mudflow at Mount Rainier . Over this pyroclastic sequences, lacustrine beds developed temporally. Thus, beyond alluvial settings, ancient lakes, with hydrothermal influence, where developed and latter basaltically surrounded thanks to
175-578: A party under expedition leader Robert Falcon Scott crossed into East Antarctica at a location now known as Ferrar Glacier , named after the geologist of the expedition. They explored part of Victoria Land on the Antarctic Plateau before returning via the same glacier. In 1908, Ernest Shackleton 's party crossed the mountains through the Beardmore Glacier . Scott returned to that same glacier in 1911, while Roald Amundsen crossed
210-726: A special Antarctic phenomenon: landscapes that are snow and ice-free due to the extremely limited precipitation and ablation of ice in the valleys. The highest mountain of the TAM is the 4,528 m (14,856 ft) high Mount Kirkpatrick in the Queen Alexandra Range . Penguins, seals, and sea birds live along the Ross Sea coastline in Victoria Land, while life in the interior of the Transantarctic Range
245-866: Is a major mountain range about 100 nautical miles (190 km; 120 mi) long, bordering the entire western side of Beardmore Glacier from the Polar Plateau to the Ross Ice Shelf . The range is in the Transantarctic Mountains System, and is located in the Ross Dependency region of Antarctica . The Queen Alexandra Range was discovered on the journey toward the South Pole by the British Antarctic Expedition, 1907–09 (BrAE), and
280-575: Is limited to bacteria, lichens , algae , and fungi. Forests once covered Antarctica, including plentiful Wollemi pines and southern beeches . However, with the gradual cooling associated with the break-up of Gondwana , these forests gradually disappeared. It is believed that the last trees on the Antarctic continent were on Transantarctic Mountains. The Transantarctic Mountains were first seen by Captain James Clark Ross in 1841 from
315-753: The Law Glacier in the Bowden Névé which feeds the Lennox-King Glacier . This glacier bounds the northwest part of the range, and separates it from the Holland Range to the north. The northern tip of the range extends to the Ross Ice Shelf between the Lennox King Glaciers and Beardmore Glacier. Download coordinates as: Mountains and peaks over 3,000 metres (9,800 ft) high include: Major features that are
350-892: The Silurian period and continuing into the Jurassic . In many places, the Beacon Supergroup has been intruded by dikes and sills of Jurassic age Ferrar Dolerite . Many of the fossils found in Antarctica are from locations within these sedimentary formations. Ice from the East Antarctic Ice Sheet flows through the Transantarctic Mountains via a series of outlet glaciers into the Ross Sea, Ross Ice Shelf, and West Antarctic Ice Sheet . These glaciers generally flow perpendicular to
385-598: The Transantarctic Mountains , from the Weddell Sea region to North Victoria Land , covering approx. 3,500 km in length. This event was linked with the initial stages of the breakup of the Gondwanan part of Pangea , concretely with the rifting of East Antarctica and Southern Africa , developing a magmatic flow controlled by an Early Jurassic zone of extension related to a triple junction in
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#1732787599476420-492: The "Carapace sandstones", alluvial/lacustrine, both deposited in a setting defined by Ballance and Watters (1971) as composed by “shallow, northeast flowing, ephemeral streams on a subsiding alluvial plain”. The Mawson Formation was thus, heavily influenced by vulcanism, with tuff-breccia deposits dropped in a <100 m paleotopography valley in Coombs Hills, probably reduced from previous erosion events, while at Allan Hills
455-863: The "Chacritas Paleolake" of the sister Cañadón Asfalto Formation in Patagonia, developed following the local rift in a similar way to the modern Lake Magadi in the Kenyan Rift Valley , as proven by the discovery of Chert like the one found in this african lake, what suggest that both, Carapace and Chacritas where likely alkaline lakes that had notorious influence of hydrothermal fuids. Other more recent lacustrine/fluvial sequences have been described in new outcrops, like at Suture Bench and SW Gair Mesa , with abundant invertebrate and plant fossils. The Formation includes two main locations: Carapace Nunatak in South Victoria Land , representing
490-782: The Kirkpatrick Basalt during the Early Jurassic splitting of Gondwana represent unusual freshwater paleoenvironments, with hotter conditions that allow to the diversification of the microbes ( Archea ). According to Barrett, "...the basalt-dominated Mawson Formation and tholeiitic flows (Kirkpatrick Basalt)...are included in the Ferrar Group ." The Mawson Formation consists of diamictites , explosion breccias , and lahar flows , evidence of magma entering water-saturated sediments . The Kirkpatrick Basalts (180 Ma ) have interbedded lake sediments with plant and fish fossils. There abundant Fossils of microorganisms, as members of
525-450: The Mawson Formation have recovered Permian and Triassic material, which was eroded by lavas, with the presence of tachylite pyroclasts that imply rapid cooling by interaction with water. The Mawson Formation was described originally subdivided in two sections, that where identified as separate units. This, is due to a clear differentiation of two kinds of deposits: the so-called "Mawson Tuffs", representing lithified pyroclastic material and
560-467: The Ross Sea. The range is a natural barrier that must be crossed to reach the South Pole from the Ross Ice Shelf . The first crossing of the Transantarctic Mountains took place during the 1902–1904 British National Antarctic Expedition at the Ross Ice Shelf. A reconnaissance party under the command of Albert Armitage reached 2,700 m (8,900 ft) altitude in 1902. The following year,
595-703: The Sections Complete Specimens A Freshwater member of Isopoda . Shows affinities with specimens from the Upper Triassic of New South Wales Scoyenia All the Sections Burrows Burrow fossils in lacustrine environment, probably made by arthropods Syncarida All the Sections Complete Specimens A Freshwater member of Syncarida . Oribatida Indeterminate Transantarctic Mountains The Transantarctic Mountains (abbreviated TAM ) comprise
630-695: The Transantarctic Mountains the ranges from Cape Adare to the Queen Maud Mountains, but extending thence through the Whitmore Mountains and Ellsworth Mountains up the Antarctic Peninsula . The 100–300 km (60–200 mi) wide range forms the boundary between East Antarctica and West Antarctica. The East Antarctic Ice Sheet bounds the TAM along their entire length on the Eastern Hemisphere side, while
665-753: The Western Hemisphere side of the range is bounded by the Ross Sea in Victoria Land from Cape Adare to McMurdo Sound , the Ross Ice Shelf from McMurdo Sound to near the Scott Glacier, and the West Antarctic Ice Sheet beyond. The large summits and dry valleys of the TAM are some of the few places in Antarctica not covered by ice, the highest of which rise more than 4,500 metres (14,800 ft) above sea level. The McMurdo Dry Valleys lie near McMurdo Sound and represent
700-618: The continent, which are mainly volcanic in origin. The range was uplifted during the opening of the West Antarctic Rift System to the east, beginning about 65 million years ago in the early Cenozoic , and soon after became occupied by glaciers. The mountains consist of sedimentary layers lying upon a basement of granites and gneisses . The sedimentary layers include the Beacon Supergroup sandstones , siltstones , and coal deposited beginning in
735-557: The dead carapace. Darwinula All the Sections Valves Common Early Jurassic Freshwater ostracod . The specimens of this genus cannot be identified to species level, yet bear resemblance with specimens from the same age of South Africa, as well as Triassic specimens from India. Isopodichnus All the sections Braided Structures Freshwater tubular braided Structures. Interpreted as traces of crustaceans searching for food in
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#1732787599476770-449: The group Archea and other who take advantage of the hydrothermal activity The Acuatic fauna, dominated by invertebrates, includes a diversity of species complete enough to establish Trophic chains: there are traces of feeding, including a coprolite of uncertain affinity with a fish scale, conchostracan valves with traces of possible biotic borings and palynological residues linked with Ostracodan valves. Demospongiae Indeterminate All
805-579: The ice divide". These geographic features are likely to have a significant impact on models and calculations related to ice flow through the Transantarctic Mountain region. In geographic order, from the Ross Sea towards the Weddell Sea : Queen Alexandra Range The Queen Alexandra Range ( 84°00′S 168°00′E / 84.000°S 168.000°E / -84.000; 168.000 ( Queen Alexandra Range ) )
840-501: The lacustrine bottom Lepidurus All the Sections Complete Specimens A Freshwater member of Notostraca . Represented by specimens much bigger than forms (20 mm compared with smaller 10–12 mm breadth) from South Africa Lioestheria All the Sections Carapaces A Freshwater member of Diplostraca (Spinicaudatan). Correlated with coeval East African and Indian lioestheriids Protamphisopus All
875-416: The most common fossil animal in the unit. Cornia All the Sections Carapaces A Freshwater member of Diplostraca (Spinicaudatan). Represents the only Jurassic Records of the genus, know mostly from Permian and Triassic deposits, being a possible relict genus. Specimens recovered show different variations in coloration, what can indicate effects of hydrothermal influence on either the living animal or
910-427: The orientation of the range and define subranges and peak groups. It has been thought that many of these outlet glaciers follow the traces of large-scale geologic faults . However, the ice flow theories will be re-evaluated in light of new data from recent ice-penetrating radar surveys which revealed the presence of three previously unknown deep subglacial valleys affecting the "mountainous subglacial topography beneath
945-683: The proto- Weddell Sea region at approximately 55°S. This eruptions phase includes the Dufek Intrusion , the Ferrar Dolerite sills and dikes, extrusive rocks consisting of pyroclastic strata, and the Kirkpatrick Basalt lava flows, with a total thickness variable, but exceeding 2 km in some places. This Volcanism is not limited to the Antarctica, as it was recorded also in Tasmania and New Zealand , suggesting that these area where connected back then. The Paleovulcanology analisis of
980-623: The range via the Axel Heiberg Glacier . Much of the range remained unexplored until the late 1940s and 1950s, when missions such as Operation Highjump and the International Geophysical Year (IGY) made extensive use of aerial photography and concentrated on a thorough investigation of the entire continent. The name "Transantarctic Mountains" was first applied to this range in a 1960 paper by geologist Warren B. Hamilton , following his IGY fieldwork. It
1015-640: The relationships with the overliying Kirckpatrick Basalt . This deposits mark the know locally as "Mawson Time", a section of the sedimentological evolution of the Ferrar Range, where volcanic material deposited in Allan Hills and Coombs Hills , while the Carapace Sandstones hosted an alluvial plain that recovered all the volcanic detritus, being latter flooded and developing a lacustrine ecosystem. The described lacustrine system was, like
1050-473: The sections Borings in invertebrate valves Holes of random pattern in valves. Boring Traces on local Conchostracan valves are common and suggested to resemble the boring traces of extant sponges, yet there isn't any evidence of Porifera fossils in the local beds Carapacestheria All the Sections Carapaces A Freshwater member of Diplostraca (Spinicaudatan). Related to the modern Cyzicus mexicanus and recovered in siliclastic interbeds, representing
1085-757: The theory of continental drift . The Queen Alexandra Range is bounded by the Beardmore Glacier along its southeast edge, which divides it from the Commonwealth Range of the Queen Maud Mountains to the east. The west of the range is bounded by the Antarctic Plateau in the south. Further north it is bounded by the Walcott Névé to the east, which separates the range from the Colbert Hills . The Walcott Névé joins
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1120-540: The volcanic materials from sources located far away of the alluvial setting. The "Lake Carapace" also shows temporal exposed paleosoils, with and without roots, as well with muds cracks, indicating seasonal droughts. This lacustrine-type deposit is also found on the second main fossiliferous outcrops of the formation, being in the Queen Alexandra Range in the Central Transantarctic Mountains. Sedimentary interbeds deposited over lava flows of
1155-552: Was later named the Ross Ice Shelf in his honour. It was first crossed during the British National Antarctic Expedition of 1901-1904. The mountain range stretches between the Ross Sea and the Weddell Sea , the entire width of Antarctica, hence the name. With a total length of about 3,500 km (2,000 mi), the Transantarctic Mountains are one of the longest mountain ranges on Earth. The Antarctandes are even longer, having in common with
1190-556: Was named by Ernest Shackleton for Queen Alexandra , Queen of the United Kingdom, 1901-10. Shackleton and his men, and a later expedition headed by Robert Falcon Scott , both collected rock samples from the range that contained fossils . The discovery that multicellular life forms had lived so close to the South Pole was an additional piece of evidence that accompanied the publication (in 1910 and independently in 1912) of
1225-596: Was subsequently recommended by the Advisory Committee on Antarctic Names , a US authority on geographic names, in 1962. This purely descriptive label (in contrast to many other geographic names on Antarctica) is internationally accepted at present. The Leverett Glacier in the Queen Maud Mountains is the planned route through the TAM for the overland supply road between McMurdo Station and Amundsen–Scott South Pole Station . The Transantarctic Mountains are considerably older than other mountain ranges of
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