Terrane Sta7ons: seismic tomography explains where the North
... Intermiwent strong coupling of terranes to Farallon plate, due to accre)on of a buoyant oceanic plateau (Shatsky Rise conjugate, B3). A corresponding slab window is clearly imaged, explains Tarahumara ignimbrit ...
... Intermiwent strong coupling of terranes to Farallon plate, due to accre)on of a buoyant oceanic plateau (Shatsky Rise conjugate, B3). A corresponding slab window is clearly imaged, explains Tarahumara ignimbrit ...
Uplift at lithospheric swellsI: seismic and gravity
... islands given the recording instrument locations. Using MCS reflection and gravity data acquired during the ‘RRS Charles Darwin’ geophysical survey in 1985 (Fig. 2), Ali et al. (2003) mapped flexural horizons in the moat sediments of the islands and investigated the shallow crustal structure down to ...
... islands given the recording instrument locations. Using MCS reflection and gravity data acquired during the ‘RRS Charles Darwin’ geophysical survey in 1985 (Fig. 2), Ali et al. (2003) mapped flexural horizons in the moat sediments of the islands and investigated the shallow crustal structure down to ...
Deep structure of the northeastern Japan arc
... suggests that the volcanic front is formed by this hot upwelling flow. Aqueous fluids supplied by the subducted slab are probably transported upward through this upwelling flow to reach shallow levels beneath the Backbone Range where they are expelled from solidified magma and migrate further upward ...
... suggests that the volcanic front is formed by this hot upwelling flow. Aqueous fluids supplied by the subducted slab are probably transported upward through this upwelling flow to reach shallow levels beneath the Backbone Range where they are expelled from solidified magma and migrate further upward ...
Scandium Iain M. Samson Department of Earth and Environmental
... [ScPO4] and kolbeckite [ScPO4·2H2O]. A number of scandium-bearing oxides have been recognized, and most of these occur in meteorites, such as allendeite [Sc4Zr3O12], named for its type locality, the Allende meteorite. These minerals are rare and, as described above, most scandium on Earth occurs as ...
... [ScPO4] and kolbeckite [ScPO4·2H2O]. A number of scandium-bearing oxides have been recognized, and most of these occur in meteorites, such as allendeite [Sc4Zr3O12], named for its type locality, the Allende meteorite. These minerals are rare and, as described above, most scandium on Earth occurs as ...
Anisotropy and deformation beneath the Eastern Alps
... Based on seismic observations, our planet is separated into three major zones; cores, mantle, and crust. According to rock rheology and thermal divisions the outer shell of the Earth is defined as the lithosphere. This body, consisting of the rigid upper mantle and crust, is considered to be cold an ...
... Based on seismic observations, our planet is separated into three major zones; cores, mantle, and crust. According to rock rheology and thermal divisions the outer shell of the Earth is defined as the lithosphere. This body, consisting of the rigid upper mantle and crust, is considered to be cold an ...
Geochemistry of Jurassic Oceanic Crust beneath
... 1996; Thirlwall, 1997). Estimates of recycling ages are critically dependent on the effects of hydrothermal alteration near the ridge axis and the subduction process on the Pb isotope systematics of ocean crust. Ocean island basalts have long been considered to be one of the major means for evaluati ...
... 1996; Thirlwall, 1997). Estimates of recycling ages are critically dependent on the effects of hydrothermal alteration near the ridge axis and the subduction process on the Pb isotope systematics of ocean crust. Ocean island basalts have long been considered to be one of the major means for evaluati ...
References
... planes [19,25], and not by intergranular flow. The migration may be facilitated because these rocks were probably undergoing deformation at the same time. The fluids are emitted cold or lukewarm, but were generated at temperatures well above 10000C, so they must have given off their heat content to ...
... planes [19,25], and not by intergranular flow. The migration may be facilitated because these rocks were probably undergoing deformation at the same time. The fluids are emitted cold or lukewarm, but were generated at temperatures well above 10000C, so they must have given off their heat content to ...
Crustal Structure at the Continental Margin South of South Africa
... In a number of areas, the geological basement crops out extensively on the sea floor; these areas are shown in Fig. 2. Those areas holding the greatest implications for the gravity interpretation are the Agulhas Arch antiform of Palaeozoic and Precambrian rocks (Gentle 1970), the Agulhas marginal fr ...
... In a number of areas, the geological basement crops out extensively on the sea floor; these areas are shown in Fig. 2. Those areas holding the greatest implications for the gravity interpretation are the Agulhas Arch antiform of Palaeozoic and Precambrian rocks (Gentle 1970), the Agulhas marginal fr ...
TROPICS Continent-Building in Costa Rica
... Additional processes are necessary to account for the great thickness of the lithosphere beneath continents. These lithospheric mantle “roots” are 200-250 km thick under some cratons, the oldest (Archean) regions of the continents. While this root is believed to record protracted melt extraction, th ...
... Additional processes are necessary to account for the great thickness of the lithosphere beneath continents. These lithospheric mantle “roots” are 200-250 km thick under some cratons, the oldest (Archean) regions of the continents. While this root is believed to record protracted melt extraction, th ...
Mountain Building Web Activity
... the crustal root is below the surface and is not affected by the mountain range above it the crust will need more support, and the mantle provides better support than the crust When material is removed from the top of a mountain range by erosion (elevation decreases), what will happen to the positio ...
... the crustal root is below the surface and is not affected by the mountain range above it the crust will need more support, and the mantle provides better support than the crust When material is removed from the top of a mountain range by erosion (elevation decreases), what will happen to the positio ...
Dynamic elevation of the Cordillera, western United States
... striking and enigmatic geophysical expressions (Plate 1). Many different processes have shaped the landscape, and often they occur at overlapping scales and depths, or have complex interrelationships. From a geodynamical perspective, we are particularly interested in observing and modeling the eleva ...
... striking and enigmatic geophysical expressions (Plate 1). Many different processes have shaped the landscape, and often they occur at overlapping scales and depths, or have complex interrelationships. From a geodynamical perspective, we are particularly interested in observing and modeling the eleva ...
Geologic Provinces of the Caribbean Region
... slip at the southern boundary, indicating that these are left lateral and right lateral transform boundaries, respectively. Thrust fault solutions, typical of the upper part of convergent plate boundaries, are found in both the western and eastern margins of the plate. The depth of the hypocentres a ...
... slip at the southern boundary, indicating that these are left lateral and right lateral transform boundaries, respectively. Thrust fault solutions, typical of the upper part of convergent plate boundaries, are found in both the western and eastern margins of the plate. The depth of the hypocentres a ...
Intermediate Earth Science Teacher’s Manual
... Earth at one point, was one giant landmass. Continental drift is the movement of the continents (due to convection currents in the mantle). Fossils, rock formations, mountain ranges and the spreading ocean floor are all used as evidence for continental drift. Plate tectonics is the theory that combi ...
... Earth at one point, was one giant landmass. Continental drift is the movement of the continents (due to convection currents in the mantle). Fossils, rock formations, mountain ranges and the spreading ocean floor are all used as evidence for continental drift. Plate tectonics is the theory that combi ...
Auxiliary Material for Plate rotation during continental collision and
... front of the subducting plate’s continental block. Markers are placed between 0-30 km depth (z-axis) and 0-240 km from the edge of the continental block. See Figure 2 for more details on the start positions of the markers. fs06.eps Figure vi P-T paths for markers at y=1320 km from the orthogonal col ...
... front of the subducting plate’s continental block. Markers are placed between 0-30 km depth (z-axis) and 0-240 km from the edge of the continental block. See Figure 2 for more details on the start positions of the markers. fs06.eps Figure vi P-T paths for markers at y=1320 km from the orthogonal col ...
Dynamic lithosphere within the Great Basin
... 1. Introduction Earth’s tectonic plates are continuously evolving through rifting, collision, and destruction via subduction. Over long time and orogen-wide scales, these processes are relatively well understood as plate geometries and interactions are traceable back on continental scales as far as ...
... 1. Introduction Earth’s tectonic plates are continuously evolving through rifting, collision, and destruction via subduction. Over long time and orogen-wide scales, these processes are relatively well understood as plate geometries and interactions are traceable back on continental scales as far as ...
The Lithosphere-Asthenosphere Boundary
... occurs over tens of kilometers. For example, Eaton et al. (2009) showed that typical fundamentalmode surface data sets are equally well fit by a step-like drop in velocity at 160 km and a decrease in velocity of comparable amplitude that occurs from 125 to 225 km in depth. In addition, the starting m ...
... occurs over tens of kilometers. For example, Eaton et al. (2009) showed that typical fundamentalmode surface data sets are equally well fit by a step-like drop in velocity at 160 km and a decrease in velocity of comparable amplitude that occurs from 125 to 225 km in depth. In addition, the starting m ...
J
... The Upflow Zone Buoyancy forces cause the hot fluids to rise rapidly toward the seafloor, much as hot air causes a balloon to rise in the atmosphere. Initially, the upflow is focused along a conduit of high permeability, such as a fault surface. As it reaches shallow depths, the flow may continue t ...
... The Upflow Zone Buoyancy forces cause the hot fluids to rise rapidly toward the seafloor, much as hot air causes a balloon to rise in the atmosphere. Initially, the upflow is focused along a conduit of high permeability, such as a fault surface. As it reaches shallow depths, the flow may continue t ...
The continent marginal crust characteristic of nothern South China
... There are many models to explain the evolution of continental margin. The differences between these models are different extension mechanical and igneous activity. The previous studies suggest the north and south margins of the SCS was an asymmetric conjugated pair and the north part can be classif ...
... There are many models to explain the evolution of continental margin. The differences between these models are different extension mechanical and igneous activity. The previous studies suggest the north and south margins of the SCS was an asymmetric conjugated pair and the north part can be classif ...
The thermochemical structure and evolution of Earth`s mantle
... He is primordial, whereas 4 He is produced by radioactive decay of U and Th. However, it has recently been argued that high-3 He/4 He could be caused by recycled depleted lithosphere (Coltice et al. 2000; Coltice & Ricard 1999; Ferrachat & Ricard 2001). Although it was previously thought that this r ...
... He is primordial, whereas 4 He is produced by radioactive decay of U and Th. However, it has recently been argued that high-3 He/4 He could be caused by recycled depleted lithosphere (Coltice et al. 2000; Coltice & Ricard 1999; Ferrachat & Ricard 2001). Although it was previously thought that this r ...
Subduction of diverging plates and the principles of slab window
... surrounding asthenospheric mantle. In turn, these conditions alter the tectonic and magmatic evolution of the overriding plate, usually disturbing ordinary fore-arc and arc regimes. Differential lithospheric stresses on opposite sides of the triple junction contribute to disturbances in the overridi ...
... surrounding asthenospheric mantle. In turn, these conditions alter the tectonic and magmatic evolution of the overriding plate, usually disturbing ordinary fore-arc and arc regimes. Differential lithospheric stresses on opposite sides of the triple junction contribute to disturbances in the overridi ...
Geodynamics Workshop 2012 PROGRAM AND ABSTRACTS
... Recently, it was shown [3] that a thermo-chemical plume, which contains a fraction of 10-20% of eclogitic material derived from recycled oceanic crust, explains the observations much better. Due to the high eclogite density, these thermo-chemical plumes have lower buoyancy and thus generate much sma ...
... Recently, it was shown [3] that a thermo-chemical plume, which contains a fraction of 10-20% of eclogitic material derived from recycled oceanic crust, explains the observations much better. Due to the high eclogite density, these thermo-chemical plumes have lower buoyancy and thus generate much sma ...
Volcanism in the Afar Rift sustained by decompression melting with
... example of active continental rifting, where a mantle plume probably weakened the lithosphere through thermal erosion and magma infiltration. However, the location and degree of plume influence today are debated2,3 . Here we use seismic Sto-P receiver functions to image the mantle structure beneath ...
... example of active continental rifting, where a mantle plume probably weakened the lithosphere through thermal erosion and magma infiltration. However, the location and degree of plume influence today are debated2,3 . Here we use seismic Sto-P receiver functions to image the mantle structure beneath ...
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.