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Shackleton Limestone
The Shackleton Limestone is a Cambrian limestone formation of the Byrd Group of Antarctica. The age of the formation is established to be Cambrian Stage 3, dated at ranging from 520 to 516 Ma. This period correlates with the End-Botomian mass extinction. Fossils of trilobites and '' Marocella mira'' and ''Dailyatia'' have been found in the formation, named after Ernest Shackleton, who led a failed expedition into Antarctica. At time of deposition, the Antarctic Plate has been established to be just south of the equator as part of the supercontinent Pannotia, contrasting with its present position at 82 degrees southern latitude.Shackleton Limestone at .org |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when these minerals precipitate out of water containing dissolved calcium. This can take place through both biological and nonbiological processes, though biological processes, such as the accumulation of corals and shells in the sea, have likely been more important for the last 540 million years. Limestone often contains fossils which provide scientists with information on ancient environments and on the evolution of life. About 20% to 25% of sedimentary rock is carbonate rock, and most of this is limestone. The remaining carbonate rock is mostly dolomite, a closely related rock, which contains a high percentage of the mineral dolomite, . ''Magnesian limestone'' is an obsolete and poorly-defined term used variously for dolomite, for limes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botomian
Cambrian Stage 4 is the still unnamed fourth stage of the Cambrian and the upper stage of Cambrian Series 2. It follows Cambrian Stage 3 and lies below the Wuliuan. The lower boundary has not been formally defined by the International Commission on Stratigraphy. One proposal is the first appearance of two trilobite genera, ''Olenellus'' or ''Redlichia''. Another proposal is the first appearance of the trilobite species '' Arthricocephalus chauveaui''. Both proposals will set the lower boundary close to million years ago. The upper boundary corresponds to the beginning of the Wuliuan. Naming The International Commission on Stratigraphy The International Commission on Stratigraphy (ICS), sometimes referred to unofficially as the "International Stratigraphic Commission", is a daughter or major subcommittee grade scientific daughter organization that concerns itself with stratigra ... has not named the fourth stage of the Cambrian yet. In the widely used Siberian nomenclature stage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atdabanian
Cambrian Stage 3 is the still unnamed third stage of the Cambrian. It succeeds Cambrian Stage 2 and precedes Cambrian Stage 4, although neither its base nor top have been formally defined. The plan is for its lower boundary to correspond approximately to the first appearance of trilobites, about million years ago, though the globally asynchronous appearance of trilobites warrants the use of a separate, globally synchronous marker to define the base. The upper boundary and beginning of Cambrian Stage 4 is informally defined as the first appearance of the trilobite genera ''Olenellus'' or '' Redlichia'' around million years ago. Naming The International Commission on Stratigraphy has not officially named the 3rd stage of the Cambrian. The stage approximately corresponds to the "Atdabanian", which is used by geologists working in Siberia. Biostratigraphy The oldest trilobite known is ''Lemdadella'' which appears at the beginning of the '' Fallotaspis'' zone. The Cambrian radiatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holyoake Range
Holyoake Range () is a mountain range in the southern section of the Churchill Mountains, extending in a northwest–southeast direction for about between Prince Philip Glacier and Errant Glacier. It and the Churchill Mountains are part of the Transantarctic Mountains System. The Holyoake Range was named by the New Zealand Antarctic Place-Names Committee for the Rt. Hon. Keith Holyoake who, first as Minister of Agriculture, then as Prime Minister, and later as Leader of the Opposition, gave strong support to New Zealand participation in the Commonwealth Trans-Antarctic Expedition of 1956–58. Features Geographical features include: * Adams Bluff * Cambrian Bluff * Errant Glacier * Gutenberg Glacier * Hunt Mountain * Mansergh Snowfield * Melrose Peak * Mount Richter * Peters Peak Peters may refer to: People * Peters (surname) * Peters Band, a First Nations band in British Columbia, Canada Places United States * Peters, California, a census-designated place * Peters, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transantarctic Mountains
The Transantarctic Mountains (abbreviated TAM) comprise a mountain range of uplifted (primarily sedimentary rock, sedimentary) rock in Antarctica which extend, 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 was later named the Ross Ice Shelf in his honour. It was first crossed during the British National Antarctic Expedition of 1901-1904. Geography 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 , the Transantarctic Mountains are one of the longest mountain ranges on Earth. The Antarctandes are even longer, having in common with the Transantarctic Mountains the ranges from Cape Adare to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossilworks
Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database (PBDB) originated in the NCEAS-funded Phanerozoic Marine Pale ..., a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was created in 1998 by John Alroy and is housed at Macquarie University. It includes many analysis and data visualization tools formerly included in the Paleobiology Database.{{cite web, title=Frequently asked questions, url=http://www.fossilworks.org/cgi-bin/bridge.pl?page=FAQ, publisher=Fossilworks, access-date=17 December 2021 References {{Reflist External links {{Wikidata property, P842 * [Baidu] |
Equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can also be used for any other celestial body that is roughly spherical. In spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is an imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles. On and near the equator (on Earth), noontime sunlight appears almost directly overhead (no more than about 23° from the zenith) every day, year-round. Consequently, the equator has a rather stable daytime temperature throug ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Plate
The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the supercontinent Pangea), the Antarctic plate began moving the continent of Antarctica south to its present isolated location, causing the continent to develop a much colder climate. The Antarctic Plate is bounded almost entirely by extensional mid-ocean ridge systems. The adjoining plates are the Nazca Plate, the South American Plate, the African Plate, the Somali Plate, the Indo-Australian Plate, the Pacific Plate, and, across a transform boundary, the Scotia Plate. The Antarctic Plate has an area of about . It is Earth's fifth-largest tectonic plate. The Antarctic Plate's movement is estimated to be at least per year towards the Atlantic Ocean. Subduction beneath South America The Antarctic Plate started to subduct beneath South America 14 mil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shackleton Expedition
The Imperial Trans-Antarctic Expedition of 1914–1917 is considered to be the last major expedition of the Heroic Age of Antarctic Exploration. Conceived by Sir Ernest Shackleton, the expedition was an attempt to make the first land crossing of the Antarctic continent. After Roald Amundsen's South Pole expedition in 1911, this crossing remained, in Shackleton's words, the "one great main object of Antarctic journeyings". Shackleton's expedition failed to accomplish this objective, but became recognized instead as an epic feat of endurance. Shackleton had served in the Antarctic on the ''Discovery'' expedition of 1901–1904, and had led the ''Nimrod'' expedition of 1907–1909. In this new venture he proposed to sail to the Weddell Sea and to land a shore party near Vahsel Bay, in preparation for a transcontinental march via the South Pole to the Ross Sea. A supporting group, the Ross Sea party, would meanwhile establish camp in McMurdo Sound, and from there lay a series o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dailyatia
The camenellans, consisting of the genera ''Camenalla'', ''Dailyatia'', ''Kennardia'', ''Kelanella'', ''Wufengella'' and ''Lapworthella'', are a (probably monophyletic) group of Tommotiid invertebrates from the Cambrian period, reconstructed as sister to all others (plus brachiopods and phoronids). They are primarily known from isolated sclerites, but are believed to have a scleritomous, ''Halkieria''-like construction.Skovsted, C. B., Betts, M. J., Topper, T. P. & Brock, G. A. The early Cambrian tommotiid genus ''Dailyatia'' from South Australia. Mem. Assoc. Australas. Palaeontol. 48, 1–117 (2015).Murdock, D. J. E., Donoghue, P. C. J., Bengtson, S. & Marone, F. Ontogeny and micro-structure of the enigmatic Cambrian tommotiid ''Sunnaginia'' Missarzhevsky, 1969. Palaeontology 55, 661–676 (2012). This was confirmed by the discovery of ''Wufengella,'' known from articulated remains, which showed camenellans to be mobile, worm-like animals. ''Dailyatia'' and ''Camenella'' have dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Marocella
''Marocella'' is a conical shelly fossil of uncertain affinity (probably a mollusc) known from Cambrian strata of Europe, Morocco, Australia and Antarctica. Morphology Limpet-like ''Marocella '' is a low conical shell with concentric ridges that grew to a couple of centimetres in length. Affinity ''Marocella'' is thought to be a mollusc, although its position within this phylum is undetermined. Relationship to the halkieriids has also been considered. Ecology Some specimens show evidence of repairing damage caused by predators. It probably moved around on the sea floor. It was geographically widespread. Distribution Fossils of ''Marocella'' have been found in:''Marocella'' at |
