Ellsworth Land is a portion of the Antarctic continent bounded on the west by Marie Byrd Land , on the north by Bellingshausen Sea , on the northeast by the base of Antarctic Peninsula , and on the east by the western margin of the Filchner–Ronne Ice Shelf . It extends between 103°24'W and 79°45'W. The area west of 90°W is unclaimed, the area between 84°W and 90°W is claimed by Chile only, and the remainder by Chile and the United Kingdom as a part of the British Antarctic Territory . Eights Coast stretches between 103°24'W and 89°35'W, and Bryan Coast between 89°35'W and 79°45'W.
25-625: It is largely a high ice plateau, but includes the Ellsworth Mountains and a number of scattered mountain groups: Hudson , Jones , Behrendt , Hauberg , Merrick , Sweeney and Scaife Mountains . This land lies near the center of the area traversed by American explorer Lincoln Ellsworth on an airplane flight during November–December 1935. It was named for him by the Advisory Committee on Antarctic Names in 1962 to commemorate that historic transcontinental flight from Dundee Island to
50-636: A north to south configuration on the western margin of the Ronne Ice Shelf in Marie Byrd Land . They are bisected by Minnesota Glacier to form the Sentinel Range to the north and the Heritage Range to the south. The former is by far the higher and more spectacular with Mount Vinson (4,892 meters (16,050 ft)) constituting the highest point on the continent. The mountains are located within
75-436: A section. The samples are analyzed to determine their detrital remanent magnetism (DRM), that is, the polarity of Earth's magnetic field at the time a stratum was deposited. For sedimentary rocks this is possible because, as they fall through the water column, very fine-grained magnetic minerals (< 17 μm ) behave like tiny compasses , orienting themselves with Earth's magnetic field . Upon burial, that orientation
100-431: Is also commonly used to delineate the nature and extent of hydrocarbon -bearing reservoir rocks, seals, and traps of petroleum geology . Chronostratigraphy is the branch of stratigraphy that places an absolute age, rather than a relative age on rock strata . The branch is concerned with deriving geochronological data for rock units, both directly and inferentially, so that a sequence of time-relative events that created
125-534: Is due to physical contrasts in rock type ( lithology ). This variation can occur vertically as layering (bedding), or laterally, and reflects changes in environments of deposition (known as facies change). These variations provide a lithostratigraphy or lithologic stratigraphy of the rock unit. Key concepts in stratigraphy involve understanding how certain geometric relationships between rock layers arise and what these geometries imply about their original depositional environment. The basic concept in stratigraphy, called
150-411: Is preserved. For volcanic rocks, magnetic minerals, which form in the melt, orient themselves with the ambient magnetic field, and are fixed in place upon crystallization of the lava. Oriented paleomagnetic core samples are collected in the field; mudstones , siltstones , and very fine-grained sandstones are the preferred lithologies because the magnetic grains are finer and more likely to orient with
175-711: Is the Howard Nunataks Formation of quartzites, the Mt. Liptak Formation of quartzites, and the Mount Wyatt Earp Formation of quartzites. Major deformation of the sedimentary rocks occurred during the Gondwanide orogeny , followed by later uplift . The temperatures in the Ellsworth Mountains average around -30 °C (-20 °F). The best time for expeditions are November through January, mid-summer in
200-716: The Chilean Antarctic territorial claim but outside of the Argentinian and British ones. The mountains were discovered on November 23, 1935, by the American explorer Lincoln Ellsworth in the course of a trans-Antarctic flight from Dundee Island to the Ross Ice Shelf . He gave them the descriptive name Sentinel Range. The mountains were mapped in detail by the U.S. Geological Survey from ground surveys and U.S. Navy aerial photography, 1958–1966. When it became evident that
225-400: The Ross Ice Shelf . Information regarding the biodiversity of Ellsworth Land is comparatively limited due to the fewer research surveys and visitations in the region. Forty species of lichen and five of moss have been identified, with Usnea sphacelata being amongst the most prominent species in the region. Colonies of Adélie penguins have been observed on multiple offshore islands in
250-675: The Southern Hemisphere . Arranging an outing here is a difficult task, requiring either official scientific sponsorship or considerable financial resources. Stratigraphy Stratigraphy is a branch of geology concerned with the study of rock layers ( strata ) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks . Stratigraphy has three related subfields: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Catholic priest Nicholas Steno established
275-431: The law of superposition , states: in an undeformed stratigraphic sequence, the oldest strata occur at the base of the sequence. Chemostratigraphy studies the changes in the relative proportions of trace elements and isotopes within and between lithologic units. Carbon and oxygen isotope ratios vary with time, and researchers can use those to map subtle changes that occurred in the paleoenvironment. This has led to
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#1732858347505300-547: The natural remanent magnetization (NRM) to reveal the DRM. Following statistical analysis, the results are used to generate a local magnetostratigraphic column that can then be compared against the Global Magnetic Polarity Time Scale. This technique is used to date sequences that generally lack fossils or interbedded igneous rocks. The continuous nature of the sampling means that it is also a powerful technique for
325-472: The 7,500 meters (24,600 ft) thick Early Cambrian - Middle Cambrian Heritage Group overlain by the 3,000 meters (9,800 ft) thick Late Cambrian - Devonian Crashsite Group; the 1,000 meters (3,300 ft) thick Permo-Carboniferous Whiteout Conglomerate (black diamictite ) from Gondawanaland glaciation; and the 1,000 meters (3,300 ft) thick Permian Polarstar Formation consisting of black argillite , siltstone , sandstone , and coal. Within
350-956: The Heritage Group is the Union Glacier Formation of ashflow tuff - lahar deposits, the Hyde Glacier Formation of graywacke -argillite-conglomerate, the Drake Icefall Formation of black shales and marble, the Conglomerate Ridge Formation of conglomerate and quartzite , the Liberty Hills-Springer Peak-Frazier Ridge Formations of quartzite-argillite, and the Minaret Formation of marble. Within the Crashsite Group
375-491: The adjacent Amundsen Sea . 75°30′S 80°00′W / 75.500°S 80.000°W / -75.500; -80.000 This Ellsworth Land location article is a stub . You can help Misplaced Pages by expanding it . Ellsworth Mountains The Ellsworth Mountains are the highest mountain ranges in Antarctica , forming a 350 km (217 mi) long and 48 km (30 mi) wide chain of mountains in
400-588: The ambient field during deposition. If the ancient magnetic field were oriented similar to today's field ( North Magnetic Pole near the North Rotational Pole ), the strata would retain a normal polarity. If the data indicate that the North Magnetic Pole were near the South Rotational Pole , the strata would exhibit reversed polarity. Results of the individual samples are analyzed by removing
425-512: The gap may be due to removal by erosion, in which case it may be called a stratigraphic vacuity. It is called a hiatus because deposition was on hold for a period of time. A physical gap may represent both a period of non-deposition and a period of erosion. A geologic fault may cause the appearance of a hiatus. Magnetostratigraphy is a chronostratigraphic technique used to date sedimentary and volcanic sequences. The method works by collecting oriented samples at measured intervals throughout
450-593: The mountains comprise two distinct ranges, the US-ACAN restricted the application of Sentinel Range to the high northern one and gave the name Heritage Range to the southern one; the Committee recommended the name of the discoverer for this entire group of mountains. Geologically, the Ellsworth Mountains occupy a discrete block of continental crust known as the Ellsworth-Whitmore Mountain terrane. This terrane
475-437: The rock layers. Strata from widespread locations containing the same fossil fauna and flora are said to be correlatable in time. Biologic stratigraphy was based on William Smith's principle of faunal succession , which predated, and was one of the first and most powerful lines of evidence for, biological evolution . It provides strong evidence for the formation ( speciation ) and extinction of species . The geologic time scale
500-480: The rocks formation can be derived. The ultimate aim of chronostratigraphy is to place dates on the sequence of deposition of all rocks within a geological region, and then to every region, and by extension to provide an entire geologic record of the Earth. A gap or missing strata in the geological record of an area is called a stratigraphic hiatus. This may be the result of a halt in the deposition of sediment. Alternatively,
525-405: The significance of strata or rock layering and the importance of fossil markers for correlating strata; he created the first geologic map of England. Other influential applications of stratigraphy in the early 19th century were by Georges Cuvier and Alexandre Brongniart , who studied the geology of the region around Paris. Variation in rock units, most obviously displayed as visible layering,
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#1732858347505550-406: The specialized field of isotopic stratigraphy. Cyclostratigraphy documents the often cyclic changes in the relative proportions of minerals (particularly carbonates ), grain size, thickness of sediment layers ( varves ) and fossil diversity with time, related to seasonal or longer term changes in palaeoclimates . Biostratigraphy or paleontologic stratigraphy is based on fossil evidence in
575-429: The theoretical basis for stratigraphy when he introduced the law of superposition , the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized
600-525: Was developed during the 19th century, based on the evidence of biologic stratigraphy and faunal succession. This timescale remained a relative scale until the development of radiometric dating , which was based on an absolute time framework, leading to the development of chronostratigraphy. One important development is the Vail curve , which attempts to define a global historical sea-level curve according to inferences from worldwide stratigraphic patterns. Stratigraphy
625-473: Was part of the early Paleozoic amalgamation of Gondwana and consists of a 13,000 meters (43,000 ft) thick section of folded Cambrian – Permian strata , which accumulated on Grenville -age continental crust. It was likely once part of the Cape Fold Belt that was detached from southern Africa during the breakup of Gondwana and later incorporated into Antarctica. The stratigraphy consists of
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