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Geology Of Greenland
Greenland is the largest island on Earth. Only one-fifth of its surface area is exposed bedrock, the rest being covered by ice. The exposed surface is approximately 410,000 km2. The geology of Greenland is dominated by crystalline rocks of the Precambrian Shield."Greenland Geology." ''Geological Survey of Denmark and Greenland''. 20 June 2003 (retrieved 26 Dec 2010) The crystalline rocks of the Nuuk/Qeqertarsuatsiaat area comprise some of the oldest bedrock in Greenland which covers most of western Greenland. The surface has been altered several times and has an appearance as though it were shaped billions of years ago. This is one of the reasons why the Nuuk area is extraordinary and also because the particular climate zone for the area limits the vegetation which makes it poss ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caledonian Orogeny Fold In King Oscar Fjord
Caledonian is a geographical term used to refer to places, species, or items in or from Scotland, or particularly the Scottish Highlands. It derives from Caledonia, the Roman name for the area of modern Scotland. Caledonian is also used to refer to places or people in or from New Caledonia. Caledonian may also refer to: Transport * ''Caledonian'' (ship), several ships with the name * Caledonian (locomotive), an early locomotive of the Liverpool and Manchester Railway * The Caledonian, discontinued British passenger train * Caledonian Airways, former Scottish airline * Caledonian Canal, between Inverness and Fort William, Scotland * Caledonian Railway, former Scottish railway company * Caledonian Railway (Brechin), preserved steam railway * Caledonian Road (other), the name of several places in London, England * Caledonian Sleeper, a sleeper train service in Scotland Sports * Caledonian F.C., former football club from Inverness * Inverness Caledonian Thistle F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ketilidian Orogeny
The Ketilidian orogeny was a late Paleoproterozoic mountain-building event that affected southern Greenland during the period 1.85 to 1.72 Ga. The orogenic belt formed during this event, sometimes known as the Ketilidian mobile belt, forms the southern boundary to the mainly Archaean North Atlantic Craton. The belt is 250–350 km wide, much of it covered by ice. It is correlated with the Makkovik Province in Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ..., Canada, which has a similar history. References {{Reflist Orogenies of North America Proterozoic North America Geology of Greenland Paleoproterozoic orogenies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fleming Fjord Formation
The Fleming Fjord Formation, alternatively called the Fleming Fjord Group is an Upper Triassic geological formation in the northeastern coast of Jameson Land, Greenland. It consists of terrestrial sediments and is known for its fossil content. Description It is of Norian to Rhaetian age and is subdivided into three members; at the base the Edderfugledal Member, followed by the Malmros Klint Member with the Ørsted Dal Member at the top. It was deposited in a large shallow to ephemeral lake. Paleobiota The fauna of Fleming Fjord is diverse, including sauropodomorph dinosaurs, pterosaurs, temnospondyls, mammaliaforms, aetosaurs, and other taxa. Freshwater unionid bivalves and conchostracans have been reported from the Malmros Klint Member. Fish Lungfish, actinopterygian, and chondrichthyan teeth have been reported from the Malmros Klint Member. Amphibians Reptiles Besides the forms described below, a diverse ichnofauna of small and large tracks has also been repor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farish Jenkins
Farish Alston Jenkins (May 19, 1940 – November 11, 2012) was a professor at Harvard University who studied and taught paleontology. His discoveries included a transitional creature with characteristics of both fish and land animals — ''Tiktaalik roseae'' —and one of the earliest known frogs, '' Prosalirus bitis''. Early life Farish Jenkins was born in Manhattan on May 19, 1940. He was the oldest of three sons of a marketing executive but was raised by his grandmother in Colorado while his father served in World War II. While he was a student at Princeton, studying geology, Jenkins met Eleanor Tracy. He later married her and they had two children — Henry Edgar and Katherine Temperance. He obtained a master's and doctorate from Yale and served as a captain in the United States Marine Corps. As a graduate student at Yale, Jenkins took a trip to Nairobi where he is said to have taken his first interest in live animal research: "At the time, black rhinos in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyostega
''Ichthyostega'' (from el, ἰχθῦς , 'fish' and el, στέγη , 'roof') is an extinct genus of limbed tetrapodomorphs from the Late Devonian of Greenland. It was among the earliest four-limbed vertebrates in the fossil record, and was one of the first with weight-bearing adaptations for terrestrial locomotion. ''Ichthyostega'' possessed lungs and limbs that helped it navigate through shallow water in swamps. Although ''Ichthyostega'' is often labelled a 'tetrapod' due to the possession of limbs and fingers, it evolved long before true crown group tetrapods, and could more accurately be referred to as a stegocephalian or stem tetrapod. Likewise, while undoubtedly of amphibian build and habit, it is not considered a true member of the group in the narrow sense, as the first modern amphibians (members of the group Lissamphibia) appeared in the Triassic Period. Until finds of other early stegocephalians and closely related fishes in the late 20th century, ''Ichthyostega' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthostega
''Acanthostega'' (meaning "spiny roof") is an extinct genus of stem-tetrapod, among the first vertebrate animals to have recognizable limbs. It appeared in the late Devonian period (Famennian age) about 365 million years ago, and was anatomically intermediate between lobe-finned fishes and those that were fully capable of coming onto land. Description 
The ''Acanthostega'' Polydactyly in stem-tetrapods, had eight digits on each han ...
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Mantle Transition Zone
The transition zone is part of the Earth's mantle, and is located between the lower mantle and the upper mantle, between a depth of 410 and 660 km (250 to 400 mi). The Earth's mantle, including the transition zone, consists primarily of peridotite, an ultramafic igneous rock. The mantle was divided into the upper mantle, transition zone, and lower mantle as a result of sudden seismic-velocity discontinuities at depths of 410 and 660 km (250 to 400 mi). This is thought to occur as a result of rearrangement of grains in olivine (which constitutes a large portion of peridotite) at a depth of 410 km, to form a denser crystal structure as a result of the increase in pressure with increasing depth. Below a depth of 660 km, evidence suggests due to pressure changes ringwoodite minerals change into two new denser phases, bridgmanite and periclase. This can be seen using body waves from earthquakes, which are converted, reflected or refracted at the bounda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Core–mantle Boundary
The core–mantle boundary (CMB) of Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2,891 km (1,796 miles) depth beneath Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities are much slower in the outer core than in the deep mantle while S-waves do not exist at all in the liquid portion of the core. Recent evidence suggests a distinct boundary layer directly above the CMB possibly made of a novel phase of the basic perovskite mineralogy of the deep mantle named post-perovskite. Seismic tomography studies have shown significant irregularities within the boundary zone and appear to be dominated by the African and Pacific Large Low-Shear-Velocity Provinces (LLSVP). The uppermost section of the outer core is thought to be about 500 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mantle Plume
A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hotspots, such as Hawaii or Iceland, and large igneous provinces such as the Deccan and Siberian Traps. Some such volcanic regions lie far from tectonic plate boundaries, while others represent unusually large-volume volcanism near plate boundaries. Concepts Mantle plumes were first proposed by J. Tuzo Wilson in 1963 and further developed by W. Jason Morgan in 1971 and 1972. A mantle plume is posited to exist where super-heated material forms ( nucleates) at the core-mantle boundary and rises through the Earth's mantle. Rather than a continuous stream, plumes should be viewed as a series of hot bubbles of material. Reaching the brittle upper Earth's crust they form diapirs. These diapirs are "hotspots" in the crust. In particular, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cumulate Rock
Cumulate rocks are igneous rocks formed by the accumulation of crystals from a magma either by settling or floating. Cumulate rocks are named according to their texture; cumulate texture is diagnostic of the conditions of formation of this group of igneous rocks. Cumulates can be deposited on top of other older cumulates of different composition and colour, typically giving the cumulate rock a layered or banded appearance. Formation Cumulate rocks are the typical product of precipitation of solid crystals from a fractionating magma chamber. These accumulations typically occur on the floor of the magma chamber, although they are possible on the roofs if anorthite plagioclase is able to float free of a denser mafic melt. Cumulates are typically found in ultramafic intrusions, in the base of large ultramafic lava tubes in komatiite and magnesium rich basalt flows and also in some granitic intrusions. Terminology Cumulates are named according to their dominant mineralogy and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Skaergaard Intrusion
The Skaergaard intrusion is a layered igneous intrusion in the Kangerlussuaq area, East Greenland. It comprises various rock types including gabbro, ferro diorite, anorthosite and granophyre. Discovered by Lawrence Wager in 1931 during the British Arctic Air Route Expedition led by Gino Watkins, the intrusion has been important to the development of key concepts in igneous petrology, including magma differentiation and fractional crystallisation and the development of layering. The Skaergaard intrusion formed when tholeiitic magma was emplaced about 55 million years ago,Brooks, CK, Gleadow, AJW (1977) ''A fission-track age for the Skaergaard intrusion and the age of the East Greenland basalts''. Geology, v. 5, p. 539-540. during the initial opening of the North Atlantic Ocean. The body represents essentially a single pulse of magma, which crystallized from the bottom upward and the top downward. The intrusion is characterized by exceptionally well-developed cumulate layering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanogenic Massive Sulfide Ore Deposit
Volcanogenic massive sulfide ore deposits, also known as VMS ore deposits, are a type of metal sulfide ore deposit, mainly copper-zinc which are associated with and created by volcanic-associated hydrothermal events in submarine environments. These deposits are also sometimes called volcanic-hosted massive sulfide (VHMS) deposits. The density generally is 4500 kg/m3. They are predominantly stratiform accumulations of sulfide minerals that precipitate from hydrothermal fluids on or below the seafloor in a wide range of ancient and modern geological settings. In modern oceans they are synonymous with sulfurous plumes called black smokers. They occur within environments dominated by volcanic or volcanic derived (e.g., volcano-sedimentary) rocks, and the deposits are coeval and coincident with the formation of said volcanic rocks. As a class, they represent a significant source of the world's copper, zinc, lead, gold and silver ores, with cobalt, tin, barium, sulfur, seleniu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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