Tectonics review
... the intention therefore to exploit our current knowledge and database constructively that makes this proposal exciting. I do not know the two field areas proposed from personal experience. However, my knowledge of other exposures of (upper) mantle suggests that whilst some lithologies are indeed re ...
... the intention therefore to exploit our current knowledge and database constructively that makes this proposal exciting. I do not know the two field areas proposed from personal experience. However, my knowledge of other exposures of (upper) mantle suggests that whilst some lithologies are indeed re ...
PLATE TECTONICS - Part I
... spreading Basaltic magmas arise from decompression melting of hot ascending asthenosphere beneath the mid ocean ridge As new oceanic lithosphere is constructed at the mid ocean ridge, older plate material passively moves off and away from both sides of ridge Most oceanic lithosphere will event ...
... spreading Basaltic magmas arise from decompression melting of hot ascending asthenosphere beneath the mid ocean ridge As new oceanic lithosphere is constructed at the mid ocean ridge, older plate material passively moves off and away from both sides of ridge Most oceanic lithosphere will event ...
Seismic reflection image of the Great Sumatra
... reflector (BT) is observed, possibly marking the position of the continental backstop of the wedge, i.e. of Sumatran continental crust. This inference is corroborated by the presence of sub-horizontal reflectors at ~9 s, where the continental Moho would be anticipated20 (Figures 2, 4). Therefore, th ...
... reflector (BT) is observed, possibly marking the position of the continental backstop of the wedge, i.e. of Sumatran continental crust. This inference is corroborated by the presence of sub-horizontal reflectors at ~9 s, where the continental Moho would be anticipated20 (Figures 2, 4). Therefore, th ...
... minerals makes oceanic lithosphere strong in the depth range where continental lithosphere appears to be weakest (1). What then is the role of the mantle lithosphere beneath continents? Is it cut by faults, or narrow shear zones, that separate effectively rigid bodies, as if plate tectonics occurred ...
The Rock Cycle
... Both oceanic and continental crust are welded to lithospheric mantle (the hard, brittle, uppermost part of mantle to form lithospheric plates). Bottom line: oceanic lithosphere (oceanic crust + lithospheric mantle) is heavy and thin whereas continental lithosphere (continental crust + lithospheric m ...
... Both oceanic and continental crust are welded to lithospheric mantle (the hard, brittle, uppermost part of mantle to form lithospheric plates). Bottom line: oceanic lithosphere (oceanic crust + lithospheric mantle) is heavy and thin whereas continental lithosphere (continental crust + lithospheric m ...
Convergent Plate Boundaries
... • Earth’s interior is layered, and the layers are arranged by density. Each deeper layer is denser than the layer above. • Continents are not supported above sea level by resting mechanically on a rigid base. Instead, continents rise to great height because they “float” on a dense, deformable layer ...
... • Earth’s interior is layered, and the layers are arranged by density. Each deeper layer is denser than the layer above. • Continents are not supported above sea level by resting mechanically on a rigid base. Instead, continents rise to great height because they “float” on a dense, deformable layer ...
The Background of Plate Tectonics - Hadeln
... fossils ended up being uncovered only in Southern Africa, South America, India, Madagascar, Melbourne and Eastern Antarctica. This likelihood guided him to hypothesize that these particular continents, now segregated by oceans, were at one point become a member of. Wegener proposed that this contine ...
... fossils ended up being uncovered only in Southern Africa, South America, India, Madagascar, Melbourne and Eastern Antarctica. This likelihood guided him to hypothesize that these particular continents, now segregated by oceans, were at one point become a member of. Wegener proposed that this contine ...
The mantle plume debate in undergraduate
... positions in the plume debate. The question, choices offered, and results are presented in Table 1. The five available choices were written to offer strong and moderate, pro-plume and plumeskeptical responses as well as a middle-of-the-road response. The results of this question were used to filter ...
... positions in the plume debate. The question, choices offered, and results are presented in Table 1. The five available choices were written to offer strong and moderate, pro-plume and plumeskeptical responses as well as a middle-of-the-road response. The results of this question were used to filter ...
Formation of Gems and Minerals
... becomes concentrated in the molten rock because it does not get incorporated into most minerals that crystallize. Consequently, the last, uncrystallized fraction is rich water and other unusual elements that also do not like to go into ordinary minerals. – When this water-rich magma is expelled in t ...
... becomes concentrated in the molten rock because it does not get incorporated into most minerals that crystallize. Consequently, the last, uncrystallized fraction is rich water and other unusual elements that also do not like to go into ordinary minerals. – When this water-rich magma is expelled in t ...
Earth's Heat
... total heat flux, with the remainder assumed to be residual heat from the planet's formation, accretion, and differentiation. This is not a total surprise based on models already formulated for the Earth's interior, but from a geochemistry perspective, it will be intriguing to follow the development ...
... total heat flux, with the remainder assumed to be residual heat from the planet's formation, accretion, and differentiation. This is not a total surprise based on models already formulated for the Earth's interior, but from a geochemistry perspective, it will be intriguing to follow the development ...
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... supplied by sublithosphere ¯ow through the Caribbean and Scotia gaps, each about 600 km wide, then the out¯ow rate is about 38 cm yr)1 (Alvarez, 1982; p. 6701). The 1982 paper argued that this out¯ow should drag the Caribbean plate eastward by viscous coupling, but it could not be determined whether ...
... supplied by sublithosphere ¯ow through the Caribbean and Scotia gaps, each about 600 km wide, then the out¯ow rate is about 38 cm yr)1 (Alvarez, 1982; p. 6701). The 1982 paper argued that this out¯ow should drag the Caribbean plate eastward by viscous coupling, but it could not be determined whether ...
Introduction - Assets - Cambridge University Press
... crustal density is approximately 2.8 × 103 kg m−3 ) reaches a subduction zone, it may descend a short way, but, because the mantle density is so much greater (approximately 3.3 × 103 kg m−3 ), the downwards motion does not continue. Instead, the subduction zone ceases to operate at that place and mo ...
... crustal density is approximately 2.8 × 103 kg m−3 ) reaches a subduction zone, it may descend a short way, but, because the mantle density is so much greater (approximately 3.3 × 103 kg m−3 ), the downwards motion does not continue. Instead, the subduction zone ceases to operate at that place and mo ...
Oceanography Questions for Test 1
... b. (4) Would you expect to find biogenic ooze in location (1)? Explain your answer. No, because the supply of lithogenous material from rivers, deserts, glaciers (depending where you are) typically dilutes any biogenic contribution to sediment formation (below the critical 30%). ...
... b. (4) Would you expect to find biogenic ooze in location (1)? Explain your answer. No, because the supply of lithogenous material from rivers, deserts, glaciers (depending where you are) typically dilutes any biogenic contribution to sediment formation (below the critical 30%). ...
Towards absolute plate motions constrained by lower
... as indicated by geochemical signatures28 . Recycling times of subducted oceanic lithosphere can be as short as a few hundred million years as indicated in the isotope geochemistry of some mantle plumes29,30 . These short recycling times suggest that the deepest slab remnants may be the elusive sourc ...
... as indicated by geochemical signatures28 . Recycling times of subducted oceanic lithosphere can be as short as a few hundred million years as indicated in the isotope geochemistry of some mantle plumes29,30 . These short recycling times suggest that the deepest slab remnants may be the elusive sourc ...
A case for mantle plumes
... Menard[5]). The reality of the age progression of the Hawaiian-Emperor island and seamount chain has by now been very well established quantitatively[6]. Morgan proposed there are about 20 plumes, and others have argued for 40 or more, although the case becomes less clear as weaker candidates are co ...
... Menard[5]). The reality of the age progression of the Hawaiian-Emperor island and seamount chain has by now been very well established quantitatively[6]. Morgan proposed there are about 20 plumes, and others have argued for 40 or more, although the case becomes less clear as weaker candidates are co ...
3D Imaging of the Earth`s Lithosphere Using Noise from Ocean Waves
... common in oceanic environments [e.g. Afonso et al., 2008b; Karato, 2012; Kawakatsu et al., 2009; Rychert and Shearer, 2011; Olugboji et al., 2013; Naif et al., 2013], where evidence for sharp seismic discontinuities (which in some cases may coincide with the base of the lithosphere) is clear [e.g. K ...
... common in oceanic environments [e.g. Afonso et al., 2008b; Karato, 2012; Kawakatsu et al., 2009; Rychert and Shearer, 2011; Olugboji et al., 2013; Naif et al., 2013], where evidence for sharp seismic discontinuities (which in some cases may coincide with the base of the lithosphere) is clear [e.g. K ...
Getting to Know: Development of Plate Tectonic Theory
... That is not true. Multiple lines of evidence from geology and paleontology show that the continents have changed shape and position many times in Earth’s history. Although the continents move very slowly, they can move thousands of kilometers over millions of years. ...
... That is not true. Multiple lines of evidence from geology and paleontology show that the continents have changed shape and position many times in Earth’s history. Although the continents move very slowly, they can move thousands of kilometers over millions of years. ...
Getting to Know: Development of Plate Tectonic Theory
... That is not true. Multiple lines of evidence from geology and paleontology show that the continents have changed shape and position many times in Earth’s history. Although the continents move very slowly, they can move thousands of kilometers over millions of years. ...
... That is not true. Multiple lines of evidence from geology and paleontology show that the continents have changed shape and position many times in Earth’s history. Although the continents move very slowly, they can move thousands of kilometers over millions of years. ...
Plate boundaries
... – When two oceanic slabs converge, one descends beneath the other – Often forms volcanoes on the ocean floor – If the volcanoes emerge as islands, a volcanic island arc is formed (Japan, Aleutian islands, Tonga islands) ...
... – When two oceanic slabs converge, one descends beneath the other – Often forms volcanoes on the ocean floor – If the volcanoes emerge as islands, a volcanic island arc is formed (Japan, Aleutian islands, Tonga islands) ...
2015-defense
... Strong correlation between the d410 and d660, indicating velocity anomalies constrained in the upper mantle. 15 km uplift for the Kalahari Craton, which is equal to a 1.2% Vp anomaly existing above d410 (Gao and Liu, 2014), leading to a 0.6s difference consistent with the picked time residuals. ...
... Strong correlation between the d410 and d660, indicating velocity anomalies constrained in the upper mantle. 15 km uplift for the Kalahari Craton, which is equal to a 1.2% Vp anomaly existing above d410 (Gao and Liu, 2014), leading to a 0.6s difference consistent with the picked time residuals. ...
plate tectonics - School of Ocean and Earth Science and Technology
... attempts to present the main ideas about plate tectonics within the published literature. Although Dietz was the first person to publish and to use the term seafloor spreading when referring to global tectonics, Hess is credited with the ‘‘discovery’’ of seafloor spreading because he circulated draf ...
... attempts to present the main ideas about plate tectonics within the published literature. Although Dietz was the first person to publish and to use the term seafloor spreading when referring to global tectonics, Hess is credited with the ‘‘discovery’’ of seafloor spreading because he circulated draf ...
Mantle plume
A mantle plume is a mechanism proposed in 1971 to explain volcanic regions of the earth that were not thought to be explicable by the then-new theory of plate tectonics. Some such volcanic regions lie far from tectonic plate boundaries, for example, Hawaii. Others represent unusually large-volume volcanism, whether on plate boundaries, e.g. Iceland, or basalt floods such as the Deccan or Siberian traps.A mantle plume is posited to exist where hot rock nucleates at the core-mantle boundary and rises through the Earth's mantle becoming a diapir in the Earth's crust. The currently active volcanic centers are known as ""hot spots"". In particular, the concept that mantle plumes are fixed relative to one another, and anchored at the core-mantle boundary, was thought to provide a natural explanation for the time-progressive chains of older volcanoes seen extending out from some such hot spots, such as the Hawaiian–Emperor seamount chain.The hypothesis of mantle plumes from depth is not universally accepted as explaining all such volcanism. It has required progressive hypothesis-elaboration leading to variant propositions such as mini-plumes and pulsing plumes. Another hypothesis for unusual volcanic regions is the ""Plate model"". This proposes shallower, passive leakage of magma from the mantle onto the Earth's surface where extension of the lithosphere permits it, attributing most volcanism to plate tectonic processes, with volcanoes far from plate boundaries resulting from intraplate extension.