Ocean Basin Evolution and Global
... Conventional models of global plate motions once took the form of reconstructed map snapshots through time, often without an accompanying digital rotation model describing the motions of the plates and without present-day digital plate polygons that clarify which features on Earth’s surface moved ac ...
... Conventional models of global plate motions once took the form of reconstructed map snapshots through time, often without an accompanying digital rotation model describing the motions of the plates and without present-day digital plate polygons that clarify which features on Earth’s surface moved ac ...
India-Asia collision and the Cenozoic slowdown of the Indian plate
... Figure 2. The plate circuit used to derive the velocity of India relative to Asia shown in Figure 1. The dotted area shows a region of diffuse deformation in the northeast Indian Ocean [e.g., Gordon et al., 1998]. Plate boundaries are from Bird [2003]. Abbreviations are I, India; C, Capricorn; S, So ...
... Figure 2. The plate circuit used to derive the velocity of India relative to Asia shown in Figure 1. The dotted area shows a region of diffuse deformation in the northeast Indian Ocean [e.g., Gordon et al., 1998]. Plate boundaries are from Bird [2003]. Abbreviations are I, India; C, Capricorn; S, So ...
Serpentinites - Elements Magazine
... km. In some forearc environments, buoyant serpentinites have been exhumed to the seafloor along normal faults and through tectonic processes, such as subduction erosion and the return flow of subducted material in a subduction channel (the low-viscosity interface between the two plates). Good exampl ...
... km. In some forearc environments, buoyant serpentinites have been exhumed to the seafloor along normal faults and through tectonic processes, such as subduction erosion and the return flow of subducted material in a subduction channel (the low-viscosity interface between the two plates). Good exampl ...
Dehydration of serpentinized slab mantle: Seismic evidence from southwest Japan
... Kanto, the Izu-Bonin fore-arc is subducting (Fig. 1). Beneath Tokai, in contrast, the Izu-Bonin volcanic ridge, i.e., the Izu-Shichito Ridge, is subducting. Suyehiro et al. (1996) detected a low velocity layer in the fore-arc mantle wedge of the Izu-Bonin arc by seismic refraction surveys and sugges ...
... Kanto, the Izu-Bonin fore-arc is subducting (Fig. 1). Beneath Tokai, in contrast, the Izu-Bonin volcanic ridge, i.e., the Izu-Shichito Ridge, is subducting. Suyehiro et al. (1996) detected a low velocity layer in the fore-arc mantle wedge of the Izu-Bonin arc by seismic refraction surveys and sugges ...
Simple Models of Diffuse Extension and the Pre
... The s implest model which has been suggesled for d iffuse extension and the s ubseque nt evolution of the extended arel-l is tbe '·stretc hins· · or "atte nualion " model proposed by McKenzie (1978). This model s tarts with fi unit le ngth of lithos phere of th ic kness t with a crust of thîckness t ...
... The s implest model which has been suggesled for d iffuse extension and the s ubseque nt evolution of the extended arel-l is tbe '·stretc hins· · or "atte nualion " model proposed by McKenzie (1978). This model s tarts with fi unit le ngth of lithos phere of th ic kness t with a crust of thîckness t ...
PDF (Chapter 2. Earth and Moon)
... differentiated into an iron-rich core and a crust. In these theories it proved difficult to transport molten iron to the center of the planet because of the effect of pressure on the melting point: Molten iron in the upper mantle would freeze before it reached the lower mantle. A central iron-rich n ...
... differentiated into an iron-rich core and a crust. In these theories it proved difficult to transport molten iron to the center of the planet because of the effect of pressure on the melting point: Molten iron in the upper mantle would freeze before it reached the lower mantle. A central iron-rich n ...
earth, interior structure of the
... (major chemical composition being CaCO3 and SiO2) and an underlying basaltic layer fbasalt is a fine-grained rock composed mostly of calcium-rich feldspar (CaAlzSizO8) and pyroxenes [( Mg,Fe,Ca) SiO3] ] . The basaltic layer is created at mid-oceanic ridges by the partial melting of upper mantle rock ...
... (major chemical composition being CaCO3 and SiO2) and an underlying basaltic layer fbasalt is a fine-grained rock composed mostly of calcium-rich feldspar (CaAlzSizO8) and pyroxenes [( Mg,Fe,Ca) SiO3] ] . The basaltic layer is created at mid-oceanic ridges by the partial melting of upper mantle rock ...
hanson_summer_2011_poster - Sound Ideas
... Our data indicate both formed by similar processes but do not have the same parent magma (thus are not genetically related). This study also uses geochemical data gathered from the Mt. Persis area with data from other studies to allow investigation of temporal changes in the nature of the crust bene ...
... Our data indicate both formed by similar processes but do not have the same parent magma (thus are not genetically related). This study also uses geochemical data gathered from the Mt. Persis area with data from other studies to allow investigation of temporal changes in the nature of the crust bene ...
A geological model for the structure of ridge segments in slow
... Taken together, first- and second-orderdiscontinuitiescre19881. ate a fundamentalalong-axis segmentationof slow spreading Second-orderdiscontinuitieshave smaller offsets, ranging ridges,roughly every 50 +30 km, which is expressedby largedown to <10 km. In fast spreadingcrustthey appearas over- scale ...
... Taken together, first- and second-orderdiscontinuitiescre19881. ate a fundamentalalong-axis segmentationof slow spreading Second-orderdiscontinuitieshave smaller offsets, ranging ridges,roughly every 50 +30 km, which is expressedby largedown to <10 km. In fast spreadingcrustthey appearas over- scale ...
Weathering, Erosion and Mass Movement
... Is the place within the Earth where scientist observed unexpected seismic wave changes. Average depth below ocean crust is 8 km. Average depth below continental crust is 32 km. ...
... Is the place within the Earth where scientist observed unexpected seismic wave changes. Average depth below ocean crust is 8 km. Average depth below continental crust is 32 km. ...
India-Asia collision and the Cenozoic slowdown of the Indian plate
... Figure 2. The plate circuit used to derive the velocity of India relative to Asia shown in Figure 1. The dotted area shows a region of diffuse deformation in the northeast Indian Ocean [e.g., Gordon et al., 1998]. Plate boundaries are from Bird [2003]. Abbreviations are I, India; C, Capricorn; S, So ...
... Figure 2. The plate circuit used to derive the velocity of India relative to Asia shown in Figure 1. The dotted area shows a region of diffuse deformation in the northeast Indian Ocean [e.g., Gordon et al., 1998]. Plate boundaries are from Bird [2003]. Abbreviations are I, India; C, Capricorn; S, So ...
Crustal and uppermantle structure in the Eastern Mediterranean
... crust. Although a unique explanation is not yet given, it is globally accepted that the combination of the subduction system to the west and the convergence of the plates to the east produces the westward motion of the Anatolian microplate, which is bounded by strikeslip faults, the dextral Nort ...
... crust. Although a unique explanation is not yet given, it is globally accepted that the combination of the subduction system to the west and the convergence of the plates to the east produces the westward motion of the Anatolian microplate, which is bounded by strikeslip faults, the dextral Nort ...
The origin and evolution of the Earth`s continental crust
... Archaean tonalites and trondhjemites resulted from slab melting of young hot oceanic crust. In contrast, most subduction-related rocks, now the main contributors to crustal growth, are derived from the mantle wedge above subduction zones. The contrast between the ...
... Archaean tonalites and trondhjemites resulted from slab melting of young hot oceanic crust. In contrast, most subduction-related rocks, now the main contributors to crustal growth, are derived from the mantle wedge above subduction zones. The contrast between the ...
reprint - Richard Allen
... anomalies. Fig. S2a–e, f–j shows the phase velocity maps for both the hand-picked and auto-picked data at a range of periods, and a comparison with the phase velocity maps of Pollitz and Snoke (2010) (Fig. 2a–e, Fig. S2k–o) from earthquake-based measurements. The earthquake-based approach is well es ...
... anomalies. Fig. S2a–e, f–j shows the phase velocity maps for both the hand-picked and auto-picked data at a range of periods, and a comparison with the phase velocity maps of Pollitz and Snoke (2010) (Fig. 2a–e, Fig. S2k–o) from earthquake-based measurements. The earthquake-based approach is well es ...
Edexcel A2 Geography sample chapter 8
... revision, topic by topic. Tick each box when you have: l revised and understood a topic l tested yourself l practised the exam questions and gone online to check your answers and complete the quick quizzes ...
... revision, topic by topic. Tick each box when you have: l revised and understood a topic l tested yourself l practised the exam questions and gone online to check your answers and complete the quick quizzes ...
Metamorphic core complexes
... are found in the central part of gneiss domes and are emplaced into shallow crustal levels. Gravity lows and aeromagnetic data (Klein, 1982) may confirm the presence of intrusions at depth. The formation of metamorphic core complexes may be behind the theory of isostatic rebound (e.g. Wernicke, 1988 ...
... are found in the central part of gneiss domes and are emplaced into shallow crustal levels. Gravity lows and aeromagnetic data (Klein, 1982) may confirm the presence of intrusions at depth. The formation of metamorphic core complexes may be behind the theory of isostatic rebound (e.g. Wernicke, 1988 ...
Adakitic magmas: modern analogues of Archaean granitoids
... 1995; Blais et al., 1997.. However, if plate tectoniclike processes operated, secular compositional changes in magmatism and tectonic regimes indicate that in detail, the processes were different from modern ones. Most of the differences result from greater Archaean heat production, inducing higher ...
... 1995; Blais et al., 1997.. However, if plate tectoniclike processes operated, secular compositional changes in magmatism and tectonic regimes indicate that in detail, the processes were different from modern ones. Most of the differences result from greater Archaean heat production, inducing higher ...
Himalayan Granite
... most intensely radioactive rocks on the planet. The backbone of the Karakoram range is composed of magnificent pale coloured granite, the Baltoro granites that formed between about 24 and 15 million years ago. The peaks north of the Hispar glacier, the Ogre, the Latoks, Trango Towers, Biale, Masherb ...
... most intensely radioactive rocks on the planet. The backbone of the Karakoram range is composed of magnificent pale coloured granite, the Baltoro granites that formed between about 24 and 15 million years ago. The peaks north of the Hispar glacier, the Ogre, the Latoks, Trango Towers, Biale, Masherb ...
Geology of the Rogue Valley
... collide, the heavier plate slides beneath the lighter one, creating what geologists call a convergent boundary. This is believed to be happening just off the Oregon coast where a small oceanic Juan de Fuca Plate, is moving into the large continental North American Plate. As the plates converge, the ...
... collide, the heavier plate slides beneath the lighter one, creating what geologists call a convergent boundary. This is believed to be happening just off the Oregon coast where a small oceanic Juan de Fuca Plate, is moving into the large continental North American Plate. As the plates converge, the ...
Shake, Rattle and Roll - Colorado Department of Education
... When continental plate material from one plate presses against another plate, the continental plate material is forced upward, forming mountains. When two plates are pulling apart, melted rock material rises up between the plates, creating new plate material. When continental plate material from one ...
... When continental plate material from one plate presses against another plate, the continental plate material is forced upward, forming mountains. When two plates are pulling apart, melted rock material rises up between the plates, creating new plate material. When continental plate material from one ...
Geology Background booklet
... Because the inner core (center) of the earth is the hottest part of the planet, heat radiates upward from the inner core toward the surface. As it does so, it begins to move the mantle, the liquid layer of rock beneath the earth’s crust. These movements cause convection currents that move large chun ...
... Because the inner core (center) of the earth is the hottest part of the planet, heat radiates upward from the inner core toward the surface. As it does so, it begins to move the mantle, the liquid layer of rock beneath the earth’s crust. These movements cause convection currents that move large chun ...
Unit Title: Shake, Ratle, ann RRll Colorado Teacher-Authored Instructional Unit Sample Science 7
... When continental plate material from one plate presses against another plate, the continental plate material is forced upward, forming mountains. When two plates are pulling apart, melted rock material rises up between the plates, creating new plate material. When continental plate material from one ...
... When continental plate material from one plate presses against another plate, the continental plate material is forced upward, forming mountains. When two plates are pulling apart, melted rock material rises up between the plates, creating new plate material. When continental plate material from one ...
Earth`s crust deformations in geosynclines
... current would repeat itself at the same place after a first one had occurred. This first current-system must already have been causing a certain concentration of crustal matter in the belt above the sinking current anel the higher percentage of radio-active minerals in th is matter must thus bring a ...
... current would repeat itself at the same place after a first one had occurred. This first current-system must already have been causing a certain concentration of crustal matter in the belt above the sinking current anel the higher percentage of radio-active minerals in th is matter must thus bring a ...
Plate tectonics
Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός ""pertaining to building"") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s.The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.