The discovery of a conjugate system of faults in the Wharton Basin
... Wharton Basin is east-west, but the shear zones are oblique to these preexisting structures, suggesting that the shear zones are new and not reactivated spreading-related normal faults. The sediment thickness over the normal oceanic crust, away from the fracture zones, is ~2.2 km (Figs. 4 and 5). A ...
... Wharton Basin is east-west, but the shear zones are oblique to these preexisting structures, suggesting that the shear zones are new and not reactivated spreading-related normal faults. The sediment thickness over the normal oceanic crust, away from the fracture zones, is ~2.2 km (Figs. 4 and 5). A ...
Plate tectonics began in Neoproterozoic time
... assumed in much modeling, may be almost 50% too high, for it is calculated with the false assumption of constant surface-rate thermal conductivity through oceanic lithosphere, whereas actual conductivity decreases by a factor of about two in both felsic rocks and olivine from 0° to 500 °C (Hofmeiste ...
... assumed in much modeling, may be almost 50% too high, for it is calculated with the false assumption of constant surface-rate thermal conductivity through oceanic lithosphere, whereas actual conductivity decreases by a factor of about two in both felsic rocks and olivine from 0° to 500 °C (Hofmeiste ...
The Relation Between Mantle Dynamics and Plate Tectonics: A Primer
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
A Primer
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
... tle’s gravitational potential energy through convective overturn (and of course that radiogenic heating and core cooling continue to replenish the mantle’s gravitational potential energy). However, the precise picture of how plate motions are caused by convection is far from complete. With the recog ...
Large-Scale Thermo-chemical Structure of the Deep Mantle
... (LLSVPs) located along the equator beneath Africa and the Pacific. These regions were first observed by global tomographic models in the 1990s (Tanimoto 1990; Su et al. 1994; Li and Romanowicz 1996), and more recent models provided refined images of these structures (e.g., Antolik et al. 2003; House ...
... (LLSVPs) located along the equator beneath Africa and the Pacific. These regions were first observed by global tomographic models in the 1990s (Tanimoto 1990; Su et al. 1994; Li and Romanowicz 1996), and more recent models provided refined images of these structures (e.g., Antolik et al. 2003; House ...
3-D structure of the Rio Grande Rift from 1
... Hansen et al., 2013; Levander and Miller, 2012; Miller and Eaton, 2010; West et al., 2004a; Wilson et al., 2010), joint inversions (Bailey et al., 2012; Lin et al., 2012; Moucha et al., 2008; West et al., 2004b). Many models show the main tectonic regions in North America, but do not necessarily foc ...
... Hansen et al., 2013; Levander and Miller, 2012; Miller and Eaton, 2010; West et al., 2004a; Wilson et al., 2010), joint inversions (Bailey et al., 2012; Lin et al., 2012; Moucha et al., 2008; West et al., 2004b). Many models show the main tectonic regions in North America, but do not necessarily foc ...
Upper mantle structure beneath the eastern Colorado Plateau and
... [1] The lithospheric architecture of the Colorado Plateau–Rio Grande rift transition zone reflects a narrow corridor of active tectonism and magmatism between the tectonically stable Colorado Plateau and the stable interior of North America. In this paper we analyze Bouguer gravity data, crustal thi ...
... [1] The lithospheric architecture of the Colorado Plateau–Rio Grande rift transition zone reflects a narrow corridor of active tectonism and magmatism between the tectonically stable Colorado Plateau and the stable interior of North America. In this paper we analyze Bouguer gravity data, crustal thi ...
Upper mantle structure beneath the eastern Colorado Plateau and
... [1] The lithospheric architecture of the Colorado Plateau–Rio Grande rift transition zone reflects a narrow corridor of active tectonism and magmatism between the tectonically stable Colorado Plateau and the stable interior of North America. In this paper we analyze Bouguer gravity data, crustal thi ...
... [1] The lithospheric architecture of the Colorado Plateau–Rio Grande rift transition zone reflects a narrow corridor of active tectonism and magmatism between the tectonically stable Colorado Plateau and the stable interior of North America. In this paper we analyze Bouguer gravity data, crustal thi ...
Implications of mantle plume structure for the evolution of flood basalts
... implications of this plume structure by comparing the physical and chemical characteristics of two flood basalt provinces (the Deccan and Karoo) with predictions of the dynamical model. The chronology, tectonics and geochemistry of the two provinces all fit well with the starting plume hypothesis. W ...
... implications of this plume structure by comparing the physical and chemical characteristics of two flood basalt provinces (the Deccan and Karoo) with predictions of the dynamical model. The chronology, tectonics and geochemistry of the two provinces all fit well with the starting plume hypothesis. W ...
Are `hot spots` - Durham University Community
... The origin of the term ‘hot spot’, also written ‘hotspot’, is obscure. It emerged in the 1970s to signify an active volcanic region that appeared to not fit the then-new plate tectonic hypothesis. It was originally understood to signify an unusually hot region in the mantle that gave rise to surface ...
... The origin of the term ‘hot spot’, also written ‘hotspot’, is obscure. It emerged in the 1970s to signify an active volcanic region that appeared to not fit the then-new plate tectonic hypothesis. It was originally understood to signify an unusually hot region in the mantle that gave rise to surface ...
Plate tectonics - Wikipedia, the free encyclopedia
... surface radiated like a black body.[5] Those calculations implied that, even if it started at red heat, the Earth would have dropped to its present temperature in a few tens of millions of years. Armed with the knowledge of a new heat source, scientists reasoned it was credible that the Earth was mu ...
... surface radiated like a black body.[5] Those calculations implied that, even if it started at red heat, the Earth would have dropped to its present temperature in a few tens of millions of years. Armed with the knowledge of a new heat source, scientists reasoned it was credible that the Earth was mu ...
Convergence and Collision
... volcanic arc. (b) Photo of the central Himalaya Mountains, Nepal. The highest peak, which appears to be nucleating a cloud, is Mt. Everest, the highest mountain on Earth. ...
... volcanic arc. (b) Photo of the central Himalaya Mountains, Nepal. The highest peak, which appears to be nucleating a cloud, is Mt. Everest, the highest mountain on Earth. ...
Next Generation Sunshine State Standards Chapter 7
... was improbable. Not until he learned that identical fossil organisms were known from rocks in both South America and Africa did he begin to seriously pursue this idea. Through a review of the literature, Wegener learned that most paleontologists (scientists who study the fossilized remains of organi ...
... was improbable. Not until he learned that identical fossil organisms were known from rocks in both South America and Africa did he begin to seriously pursue this idea. Through a review of the literature, Wegener learned that most paleontologists (scientists who study the fossilized remains of organi ...
The transition from diffuse to focused extension: Modeled evolution
... WARS. Model results indicate that the transition from a prolonged period of broadly distributed extension to a later period of focused rifting did not require a change in the regional stress regime (changes in plate motion), or deep mantle thermal state (impingement of a plume). Instead, we attribut ...
... WARS. Model results indicate that the transition from a prolonged period of broadly distributed extension to a later period of focused rifting did not require a change in the regional stress regime (changes in plate motion), or deep mantle thermal state (impingement of a plume). Instead, we attribut ...
the Scotia Sea and the Caribbean
... Holmes’ (1898-1965) ideas regarding mantle convection, and Harry Hess’ (1906-1969) seafloor spreading hypothesis, the theory of plate tectonics has been accepted since the 1960s. According to this theory, the Earth is subdivided into several rigid plates that move with a few centimeters per year rel ...
... Holmes’ (1898-1965) ideas regarding mantle convection, and Harry Hess’ (1906-1969) seafloor spreading hypothesis, the theory of plate tectonics has been accepted since the 1960s. According to this theory, the Earth is subdivided into several rigid plates that move with a few centimeters per year rel ...
The Statistical Upper Mantle Assemblage, Earth
... The geochemical diversity of mid-ocean ridge basalt (MORB) and oceanic island basalt (OIB) has traditionally been attributed to the existence of large-scale mantle heterogeneity, in particular to accessible reservoirs at various depths. However, reconciling the geochemical constraints for isolated, ...
... The geochemical diversity of mid-ocean ridge basalt (MORB) and oceanic island basalt (OIB) has traditionally been attributed to the existence of large-scale mantle heterogeneity, in particular to accessible reservoirs at various depths. However, reconciling the geochemical constraints for isolated, ...
Densities of metapelitic rocks at high to ultrahigh
... the return of deeply subducted continental crust by buoyancy forces requiring that the continental crust is significantly less dense than the ultrabasic upper mantle at corresponding depths. However, this could be a prejudice based on the situation at shallower depths where many ordinary rocks such ...
... the return of deeply subducted continental crust by buoyancy forces requiring that the continental crust is significantly less dense than the ultrabasic upper mantle at corresponding depths. However, this could be a prejudice based on the situation at shallower depths where many ordinary rocks such ...
Poisson`s ratio in the lower mantle beneath Alaska: Evidence for
... [4] There are, at least, two major difficulties with seismological studies of compositional heterogeneity that rely on wave speed ratios. First, without absolute values the trade-off between temperature and compositional effects cannot be resolved, so that the interpretation in terms of the origin o ...
... [4] There are, at least, two major difficulties with seismological studies of compositional heterogeneity that rely on wave speed ratios. First, without absolute values the trade-off between temperature and compositional effects cannot be resolved, so that the interpretation in terms of the origin o ...
7-3 Plate Tectonics Test
... 1. The crust and upper mantle make up Earth's ____. a. lithosphere c. core b. asthenosphere d. continents 2. Scientists have observed that the continents move apart or come together at speeds of a few centimeters per ____. a. year c. day b. decade d. century 3. Plates of the lithosphere float on the ...
... 1. The crust and upper mantle make up Earth's ____. a. lithosphere c. core b. asthenosphere d. continents 2. Scientists have observed that the continents move apart or come together at speeds of a few centimeters per ____. a. year c. day b. decade d. century 3. Plates of the lithosphere float on the ...
Mobility and immobility of mid-ocean ridges and their
... ofgeosciences to investigate whether the 'deeper origin' ridges (Su et al., 1992) have any peculiar characteristics from other ridges. ...
... ofgeosciences to investigate whether the 'deeper origin' ridges (Su et al., 1992) have any peculiar characteristics from other ridges. ...
- BIROn - Birkbeck Institutional Research Online
... the progressive closure of oceanic basins in the Mediterranean region and the collision of the Alpine orogen with the southern passive margin of Europe. Compressional deformation of the lithosphere within western and central Europe occurred as a response to the collisional coupling of the Alpine and ...
... the progressive closure of oceanic basins in the Mediterranean region and the collision of the Alpine orogen with the southern passive margin of Europe. Compressional deformation of the lithosphere within western and central Europe occurred as a response to the collisional coupling of the Alpine and ...
When and why the continental crust is subducted: Examples of
... explain why faulting can occur under such a high lithostatic pressure. In recent years, dehydration embrittlement hypothesis has been proposed for occurrence of intermediate-depth earthquakes (Raleigh and Paterson, 1965; Kirby et al., 1996; Seno and Yamanaka, 1996; Peacock and Wang, 1999; Omori et a ...
... explain why faulting can occur under such a high lithostatic pressure. In recent years, dehydration embrittlement hypothesis has been proposed for occurrence of intermediate-depth earthquakes (Raleigh and Paterson, 1965; Kirby et al., 1996; Seno and Yamanaka, 1996; Peacock and Wang, 1999; Omori et a ...
PDF (Chapter 23. The Upper Mantle)
... be generated by various stages of melting, mixing, melt extraction, depletion and enrichment and do not require the involvement of unfractionated, primitive or lower-mantle reservoirs . However, the first stage of Earth formation - the accretional stage - does involve large degrees of melting that e ...
... be generated by various stages of melting, mixing, melt extraction, depletion and enrichment and do not require the involvement of unfractionated, primitive or lower-mantle reservoirs . However, the first stage of Earth formation - the accretional stage - does involve large degrees of melting that e ...
Upper mantle flow in the western Mediterranean
... base, generally around 80–90 km deep, is interpreted to be much shallower (around 50 km) below the Cenozoic Massif Central alkaline volcanic province. Since the crust is not thinned accordingly, the volcanism and the asthenosphere upwelling are interpreted in literature as a thermal effect due to th ...
... base, generally around 80–90 km deep, is interpreted to be much shallower (around 50 km) below the Cenozoic Massif Central alkaline volcanic province. Since the crust is not thinned accordingly, the volcanism and the asthenosphere upwelling are interpreted in literature as a thermal effect due to th ...
Eduard Suess` conception of the Alpine orogeny related to
... In his treatise „Die Entstehung der Alpen“, Eduard Suess presents a wealth of geological observations and a fascinating conception of the orogeny of the Alps and mountain chains in general. It is an inspiring task to review the state of the Physics of the Earth at the time when Suess worked on this ...
... In his treatise „Die Entstehung der Alpen“, Eduard Suess presents a wealth of geological observations and a fascinating conception of the orogeny of the Alps and mountain chains in general. It is an inspiring task to review the state of the Physics of the Earth at the time when Suess worked on this ...
Post-glacial rebound
Post-glacial rebound (sometimes called continental rebound) is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostatic depression. Post-glacial rebound and isostatic depression are different parts of a process known as either glacial isostasy, glacial isostatic adjustment, or glacioisostasy. Glacioisostasy is the solid Earth deformation associated with changes in ice mass distribution. The most obvious and direct affects of post-glacial rebound are readily apparent in northern Europe (especially Scotland, Estonia, Latvia, Fennoscandia, and northern Denmark), Siberia, Canada, the Great Lakes of Canada and the United States, the coastal region of the US state of Maine, parts of Patagonia, and Antarctica. However, through processes known as ocean siphoning and continental levering, the effects of post-glacial rebound on sea-level are felt globally far from the locations of current and former ice sheets.