The Yellowstone Hotspot: Plume or Not?
... slab material, exploits a zone of weakness in the slab, or breaks through the slab (e.g., Obrebski et al., 2010). Alternatively, an upwelling plume might slip around the exposed southern edge of the subducting Juan de Fuca slab, or be drawn in from the east during westward trench retreat and Farallo ...
... slab material, exploits a zone of weakness in the slab, or breaks through the slab (e.g., Obrebski et al., 2010). Alternatively, an upwelling plume might slip around the exposed southern edge of the subducting Juan de Fuca slab, or be drawn in from the east during westward trench retreat and Farallo ...
A reassessment of the timing of early Archaean crustal
... of some massive, regional metamorphic or metasomatic event. Furthermore the initial Sr, Nd and Pb isotopic constraints are also concordant, all strongly indicating a ...
... of some massive, regional metamorphic or metasomatic event. Furthermore the initial Sr, Nd and Pb isotopic constraints are also concordant, all strongly indicating a ...
Linking rift propagation barriers to excess magmatism at volcanic
... This relates to previous analog modeling by Corti et al. (2002) who suggested that magma distribution at depth controls strain localization during transfer zone formation and that, vice versa, magma migrates toward imposed transfer zones (Corti et al., 2004). While these studies focused on magma mig ...
... This relates to previous analog modeling by Corti et al. (2002) who suggested that magma distribution at depth controls strain localization during transfer zone formation and that, vice versa, magma migrates toward imposed transfer zones (Corti et al., 2004). While these studies focused on magma mig ...
Plateau uplift in western Canada caused by lithospheric
... than 150 km and that asthenosphere directly underlies the crust beneath the plateau region. We identify a 250-km-wide seismic anomaly about 150–250 km beneath the plateau that we interpret as a block of intact, delaminated lithosphere. We suggest that mantle material upwelling along the sharp craton ...
... than 150 km and that asthenosphere directly underlies the crust beneath the plateau region. We identify a 250-km-wide seismic anomaly about 150–250 km beneath the plateau that we interpret as a block of intact, delaminated lithosphere. We suggest that mantle material upwelling along the sharp craton ...
Global mass wasting during the Middle Ordovician: Meteoritic trigger
... neglected, we challenge the idea that mass wasting was mainly produced by meteorite impacts over a period of almost 10 Ma. Having strong arguments against the impact-related hypothesis, we propose an alternative explanation, which is based on a re-evaluation of the mass wasting sites, considering th ...
... neglected, we challenge the idea that mass wasting was mainly produced by meteorite impacts over a period of almost 10 Ma. Having strong arguments against the impact-related hypothesis, we propose an alternative explanation, which is based on a re-evaluation of the mass wasting sites, considering th ...
Convergent Plate Boundaries - North Coast Distance Education
... Collisions between two continents are occurring in several places.The most dramatic is the one that produced the Himalaya Mountains and Tibetan Plateau of southern Asia. The Himalayas, Earth’s highest mountain belt, is a wide and highly deformed zone of mountains that rose as India collided with the ...
... Collisions between two continents are occurring in several places.The most dramatic is the one that produced the Himalaya Mountains and Tibetan Plateau of southern Asia. The Himalayas, Earth’s highest mountain belt, is a wide and highly deformed zone of mountains that rose as India collided with the ...
Subcontinental Lithosphere
... Judging from studies of island arc magmas, such fluids appear to be particularly enriched in soluble incompatible elements, such as the alkalis and alkaline earths. These processes in which lithosphere reacts with melts or fluids is known as mantle metasomatism*. Petrographic studies of some xenolit ...
... Judging from studies of island arc magmas, such fluids appear to be particularly enriched in soluble incompatible elements, such as the alkalis and alkaline earths. These processes in which lithosphere reacts with melts or fluids is known as mantle metasomatism*. Petrographic studies of some xenolit ...
Oceans: The Last Frontier
... Focus Question 9.4 • Describe how satellites orbiting Earth can determine features on the seafloor without being able to directly observe them beneath several kilometers of seawater. – Satellites measure differences across the ocean surface. These differences are due to water displacement caused by ...
... Focus Question 9.4 • Describe how satellites orbiting Earth can determine features on the seafloor without being able to directly observe them beneath several kilometers of seawater. – Satellites measure differences across the ocean surface. These differences are due to water displacement caused by ...
Driving the Earth machine?
... this pattern changes to just two broad upwellings (2). These upwellings are consistent with large low–shear velocity provinces seen at the base of the mantle in global tomography models (see below) (3). Although some researchers have called these upwellings superplumes, we feel that this term is con ...
... this pattern changes to just two broad upwellings (2). These upwellings are consistent with large low–shear velocity provinces seen at the base of the mantle in global tomography models (see below) (3). Although some researchers have called these upwellings superplumes, we feel that this term is con ...
Driving the Earth machine?
... this pattern changes to just two broad upwellings (2). These upwellings are consistent with large low–shear velocity provinces seen at the base of the mantle in global tomography models (see below) (3). Although some researchers have called these upwellings superplumes, we feel that this term is con ...
... this pattern changes to just two broad upwellings (2). These upwellings are consistent with large low–shear velocity provinces seen at the base of the mantle in global tomography models (see below) (3). Although some researchers have called these upwellings superplumes, we feel that this term is con ...
Lecture 19: Mantle Plumes - Earth and Atmospheric Sciences
... Recent studies of Os isotope ratios in xenoliths from the subcontinental lithosphere have been particularly enlightening. Most xenoliths derived from below regions of old continental crust have low Os isotope ratios, which imply that low Re/Os ratios were established long ago. The low Re/Os ratios a ...
... Recent studies of Os isotope ratios in xenoliths from the subcontinental lithosphere have been particularly enlightening. Most xenoliths derived from below regions of old continental crust have low Os isotope ratios, which imply that low Re/Os ratios were established long ago. The low Re/Os ratios a ...
Edmond and Huh 2003 - Department of the Geophysical Sciences
... relative to the rate of fixation by weathering, mechanisms that maintain this apparently precarious balance dominate current thinking. At present, the Atlantic and Indian oceans are major depocenters of CaCO3 , but subduction of ocean floor and the deposits on it is minimal in these basins. The locu ...
... relative to the rate of fixation by weathering, mechanisms that maintain this apparently precarious balance dominate current thinking. At present, the Atlantic and Indian oceans are major depocenters of CaCO3 , but subduction of ocean floor and the deposits on it is minimal in these basins. The locu ...
On the origin and tectonic significance of the intra-plate
... The objective of this article is to examine the available evidence of intra-plate tectonic episodes of ‘‘Grenvillian-type age”, affecting the South-American continent, assessing their possible causal correlation with the tectonic processes occurring within the orogenic belts active at their margins. ...
... The objective of this article is to examine the available evidence of intra-plate tectonic episodes of ‘‘Grenvillian-type age”, affecting the South-American continent, assessing their possible causal correlation with the tectonic processes occurring within the orogenic belts active at their margins. ...
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... effects of subduction to be expected on the continent such as arc vulcanism, heat flow and gravity; and finally the evidence from seismicity. We feel however that is is important to emphasize that each source of infomation has a different timescale. The offshore magnetic anomalies, for example, can ...
... effects of subduction to be expected on the continent such as arc vulcanism, heat flow and gravity; and finally the evidence from seismicity. We feel however that is is important to emphasize that each source of infomation has a different timescale. The offshore magnetic anomalies, for example, can ...
Methods for thermochemical convection in Earth`s mantle with force
... [1] Models of convection in the mantle can be used to study the effects of differentiation and remixing on the geochemical evolution of the Earth. Implementation of melting and degassing at mid-ocean ridges and subduction zones requires an adequate approximation of plate tectonics as well as tempera ...
... [1] Models of convection in the mantle can be used to study the effects of differentiation and remixing on the geochemical evolution of the Earth. Implementation of melting and degassing at mid-ocean ridges and subduction zones requires an adequate approximation of plate tectonics as well as tempera ...
Plate tectonics and lithosphere architecture: temporal and spatial
... Present-day. Mantle facies variation inferred from seismic (Blundell et al., 1992) and experimental data reveals (a) a thick, heterogeneous, diamond-garnet facies keel (low heat flow, high velocity anomaly) beneath the Baltic Shield; (b) thin, relatively homogeneous, garnet-spinel facies mantle (hig ...
... Present-day. Mantle facies variation inferred from seismic (Blundell et al., 1992) and experimental data reveals (a) a thick, heterogeneous, diamond-garnet facies keel (low heat flow, high velocity anomaly) beneath the Baltic Shield; (b) thin, relatively homogeneous, garnet-spinel facies mantle (hig ...
The ocean-continent transition in the uniform lithospheric stretching
... values is proved by the fact that the transition from stretched continental crust to oceanic crust, where this is documented, does not seem to be marked by a significant topographic step (see, for example, Montadert et al. 1971a, b). Thus, it can be concluded that in general the stretched continenta ...
... values is proved by the fact that the transition from stretched continental crust to oceanic crust, where this is documented, does not seem to be marked by a significant topographic step (see, for example, Montadert et al. 1971a, b). Thus, it can be concluded that in general the stretched continenta ...
i13 Drift versus land bridges Mesosaurus > - e
... deep seafloor has nowhere been flexed up to become land. Sampling of deep seafloor sediments showed that, “If such an area were elevated into a continent, it should be relatively easy to recognize it from a study of the formations.”2 Deepsea sediments only occur above sealevel in fold mountain range ...
... deep seafloor has nowhere been flexed up to become land. Sampling of deep seafloor sediments showed that, “If such an area were elevated into a continent, it should be relatively easy to recognize it from a study of the formations.”2 Deepsea sediments only occur above sealevel in fold mountain range ...
Plate Tectonics in a Nutshell Name
... magma, which quickly solidifies, forming new oceanic lithosphere. This continuous process, operating over millions of years, builds a chain of submarine volcanoes and rift valleys called a MID-OCEAN RIDGE or an OCEANIC SPREADING RIDGE. 7. As new molten rock continues to be extruded at the mid-ocean ...
... magma, which quickly solidifies, forming new oceanic lithosphere. This continuous process, operating over millions of years, builds a chain of submarine volcanoes and rift valleys called a MID-OCEAN RIDGE or an OCEANIC SPREADING RIDGE. 7. As new molten rock continues to be extruded at the mid-ocean ...
12.710 – Problem Set 4 solutions 1. What is “the geothermal
... seismic velocity profiles); the upper mantle-lower mantle boundary and the transition zone (also experiments and velocity profiles), the crust-mantle boundary, and the base of the lithosphere. Because continental crust and lithosphere are thicker than oceanic lithosphere, their gradients must have d ...
... seismic velocity profiles); the upper mantle-lower mantle boundary and the transition zone (also experiments and velocity profiles), the crust-mantle boundary, and the base of the lithosphere. Because continental crust and lithosphere are thicker than oceanic lithosphere, their gradients must have d ...
Composition of the Earth
... - direct sampling to only ~15 km. - eruptive “entrainment” sampling to 200 km, and possibly to 500 km. - mantle plume advection from the base of the mantle (2900 km). If plumes exist. - no bona fide samples yet from the core. ...
... - direct sampling to only ~15 km. - eruptive “entrainment” sampling to 200 km, and possibly to 500 km. - mantle plume advection from the base of the mantle (2900 km). If plumes exist. - no bona fide samples yet from the core. ...
view as pdf - KITP Online
... - direct sampling to only ~15 km. - eruptive “entrainment” sampling to 200 km, and possibly to 500 km. - mantle plume advection from the base of the mantle (2900 km). If plumes exist. - no bona fide samples yet from the core. ...
... - direct sampling to only ~15 km. - eruptive “entrainment” sampling to 200 km, and possibly to 500 km. - mantle plume advection from the base of the mantle (2900 km). If plumes exist. - no bona fide samples yet from the core. ...
Identify the Organelle
... Layers of the Earth Tic-Tac-Toe KEY Comparing Density Crust ↔ Mantle: The crust is less dense than the mantle Crust ↔ Core: The crust is less dense than the mantle Mantle ↔ Core: The mantle is less dense than the core Inner Core ↔ Outer Core: The inner core is more dense than the outer core ...
... Layers of the Earth Tic-Tac-Toe KEY Comparing Density Crust ↔ Mantle: The crust is less dense than the mantle Crust ↔ Core: The crust is less dense than the mantle Mantle ↔ Core: The mantle is less dense than the core Inner Core ↔ Outer Core: The inner core is more dense than the outer core ...
Press release "New model for deep mantle conveyor belt system at
... Institute of Technology report in Nature Geophysics (online 27 Feb 2017) a new model for the existence of a deep mantle conveyor belt system that may have operated inside the Earth since its formation about 4.5 billion years ago. Most earthquakes, volcanoes, mountain building, sea-floor spreading, a ...
... Institute of Technology report in Nature Geophysics (online 27 Feb 2017) a new model for the existence of a deep mantle conveyor belt system that may have operated inside the Earth since its formation about 4.5 billion years ago. Most earthquakes, volcanoes, mountain building, sea-floor spreading, a ...
20170228 press-release
... Most earthquakes, volcanoes, mountain building, sea-floor spreading, and other major geological activities on Earth are driven by so called plate tectonics, where large sections of the Earth’s crust move as coherent blocks — or plates — that crash together, pull apart, slide on top of each other, ...
... Most earthquakes, volcanoes, mountain building, sea-floor spreading, and other major geological activities on Earth are driven by so called plate tectonics, where large sections of the Earth’s crust move as coherent blocks — or plates — that crash together, pull apart, slide on top of each other, ...
Supercontinent
In geology, a supercontinent is the assembly of most or all of the Earth's continental blocks or cratons to form a single large landmass. However, the definition of a supercontinent can be ambiguous. Many tectonicists such as P.F. Hoffman (1999) use the term ""supercontinent"" to mean ""a clustering of nearly all continents"". This definition leaves room for interpretation when labeling a continental body and is easier to apply to Precambrian times. Using the first definition provided here, Gondwana (aka Gondwanaland) is not considered a supercontinent, because the landmasses of Baltica, Laurentia and Siberia also existed at the same time but physically separate from each other. The landmass of Pangaea is the collective name describing all of these continental masses when they were in a close proximity to one another. This would classify Pangaea as a supercontinent. According to the definition by Rogers and Santosh (2004), a supercontinent does not exist today. Supercontinents have assembled and dispersed multiple times in the geologic past (see table). The positions of continents have been accurately determined back to the early Jurassic. However, beyond 200 Ma, continental positions are much less certain.