OBSERVATIONAL AND THEORETICAL STUDIES OF THE DYNAMICS OF MANTLE PLUME–MID-OCEAN RIDGE INTERACTION
... [8] A number of processes over geologic time change trace element and thus isotopic ratios in the mantle from which hot spot and mid-ocean ridge basalts are derived. For example, melting extracts highly incompatible elements from mantle peridotite and concentrates these elements in crustal material. ...
... [8] A number of processes over geologic time change trace element and thus isotopic ratios in the mantle from which hot spot and mid-ocean ridge basalts are derived. For example, melting extracts highly incompatible elements from mantle peridotite and concentrates these elements in crustal material. ...
THE TECTONIC RELATIONSHIPS OF THE HILLABEE CHLORITE
... the schist. Alternating micaeous, quartz-feldspathic, and highly graphitic layers define compositional layering. Foliation (S1) formed during regional metamorphism (M1) and is approximately parallel to compositional layering. Numerous pegmatite veins and quartz dikes 1 to 5 cm thick in the schist ar ...
... the schist. Alternating micaeous, quartz-feldspathic, and highly graphitic layers define compositional layering. Foliation (S1) formed during regional metamorphism (M1) and is approximately parallel to compositional layering. Numerous pegmatite veins and quartz dikes 1 to 5 cm thick in the schist ar ...
Hotspots and Melting Anomalies - Earth and Environmental Sciences
... An intriguing, yet enigmatic form of age-progressive volcanism is represented by the PukaPuka and Sojourn Ridges, which extend NW away from the East Pacific Rise. With respect to its geographic trend and duration, the Puka-Puka Ridge resembles some of the other volcano chains the region, such as the ...
... An intriguing, yet enigmatic form of age-progressive volcanism is represented by the PukaPuka and Sojourn Ridges, which extend NW away from the East Pacific Rise. With respect to its geographic trend and duration, the Puka-Puka Ridge resembles some of the other volcano chains the region, such as the ...
Hotspots and Melting anomalies - Earth and Environmental Sciences
... from buoyant upwellings below many hotspot regions. These upwelling features are expected to be abundant in the convecting mantle but their forms, evolution, and depths of origin are likely to be much more diverse than originally conceived. Causes for hotspots that may originate above the lower mant ...
... from buoyant upwellings below many hotspot regions. These upwelling features are expected to be abundant in the convecting mantle but their forms, evolution, and depths of origin are likely to be much more diverse than originally conceived. Causes for hotspots that may originate above the lower mant ...
`granitic` laver of the crust in the southern norwegian precambrian
... however, WooLLARD (1959) presents compelling evidence for the occurrence of an intermediate layer and suggests that its top may not form a sharp velocity discontinuity in many places. Laboratory studies of transmission velocities within various rock types have been carried out in order to transform ...
... however, WooLLARD (1959) presents compelling evidence for the occurrence of an intermediate layer and suggests that its top may not form a sharp velocity discontinuity in many places. Laboratory studies of transmission velocities within various rock types have been carried out in order to transform ...
Top driven asymmetric mantle convection
... as the main decoupling surface due to its lower viscosity (Fig. 1). Shearing occurs within the superadiabatic BL, which is characterized by higher potential temperature (Tp) and the local presence of fluids and melts. In this contribution we analyze the volumes recycled into the mantle along opposit ...
... as the main decoupling surface due to its lower viscosity (Fig. 1). Shearing occurs within the superadiabatic BL, which is characterized by higher potential temperature (Tp) and the local presence of fluids and melts. In this contribution we analyze the volumes recycled into the mantle along opposit ...
Acrobat PDF file - 1 Mb (text and Table 1)
... with sharp contacts against residual mantle peridotites, common in some ophiolites and perhaps beneath fast-spreading ridges, was not a very important process in the region we investigated. Instead, melts probably were in equilibrium with mantle peridotite up to the base of the thermal boundary laye ...
... with sharp contacts against residual mantle peridotites, common in some ophiolites and perhaps beneath fast-spreading ridges, was not a very important process in the region we investigated. Instead, melts probably were in equilibrium with mantle peridotite up to the base of the thermal boundary laye ...
the Zero Paradox Noble Gas Mantle
... The greatest strength of using noble gases as tracers of mantle processes is their chemical inertness and volatility. These characteristics result in efficient outgassing of the noble gases during melting, with negligible recycling back into the mantle system, which greatly simplifies their interpre ...
... The greatest strength of using noble gases as tracers of mantle processes is their chemical inertness and volatility. These characteristics result in efficient outgassing of the noble gases during melting, with negligible recycling back into the mantle system, which greatly simplifies their interpre ...
u series disequilibria: insights into mantle melting and
... Ra, and 231Pa). The 2s precisions of 0.1– 2% can be obtained by mass spectrometer measurements of less than 2 hours duration, compared with 2 – 10% for much longer a spectrometry measurements, and sample size requirements for mass spectrometry are also significantly less than for a spectrometry (e.g ...
... Ra, and 231Pa). The 2s precisions of 0.1– 2% can be obtained by mass spectrometer measurements of less than 2 hours duration, compared with 2 – 10% for much longer a spectrometry measurements, and sample size requirements for mass spectrometry are also significantly less than for a spectrometry (e.g ...
Continent-sized anomalous zones with low
... overlie LLSVP edges than their interior. Recent tomographic work suggests broad conduits of reduced wave speeds beneath some hotspots, extending from the CMB up to ~1,000 km depth8. Earth’s largest volcanic eruptions are infrequent, massive flood basalt events, resulting in large igneous provinces ( ...
... overlie LLSVP edges than their interior. Recent tomographic work suggests broad conduits of reduced wave speeds beneath some hotspots, extending from the CMB up to ~1,000 km depth8. Earth’s largest volcanic eruptions are infrequent, massive flood basalt events, resulting in large igneous provinces ( ...
A trace element perspective on the source of ocean island basalts
... depletion as resulting from continental crust extraction in Earth’s early history (e.g., Armstrong, 1968; Gast, 1968, Hofmann, 1988), we could be satisfied with the OIB source being less depleted than the MORB source. However, the OIB source is actually more enriched in incompatible elements than th ...
... depletion as resulting from continental crust extraction in Earth’s early history (e.g., Armstrong, 1968; Gast, 1968, Hofmann, 1988), we could be satisfied with the OIB source being less depleted than the MORB source. However, the OIB source is actually more enriched in incompatible elements than th ...
MAJOR-ELEMENT CHEMISTRY OF PLUTONIC ROCK SUITES
... directly be related to melting and dehydration of the subducted ocean crust. Other processes that may be important are: lowering of the solidus of the overlying peridotitic mantle wedge resulting in partial melting; fractionation of both primary melts; extensive reaction of these melts with the cont ...
... directly be related to melting and dehydration of the subducted ocean crust. Other processes that may be important are: lowering of the solidus of the overlying peridotitic mantle wedge resulting in partial melting; fractionation of both primary melts; extensive reaction of these melts with the cont ...
Volatile Cycling of H2O, CO2, F, and Cl in the HIMU Mantle: A New
... radiogenic Pb-isotopic signature associated with the HIMU mantle domain [Chase, 1981; Hofmann and White, 1982]. A recycled origin for the HIMU mantle end-member has been further supported by sulfur isotopic measurements from olivine-hosted melt inclusions from Mangaia, which confirm that the material ...
... radiogenic Pb-isotopic signature associated with the HIMU mantle domain [Chase, 1981; Hofmann and White, 1982]. A recycled origin for the HIMU mantle end-member has been further supported by sulfur isotopic measurements from olivine-hosted melt inclusions from Mangaia, which confirm that the material ...
Numerical models, geochemistry and the zero-paradox noble
... The continuing interplay between the processes of chemical differentiation at the Earth’s near surface and the dynamics of mixing in the mantle system variably work to create and destroy the geochemical record of the Earth’s past. Two apparently incompatible conceptual models of whole-Earth behaviour ...
... The continuing interplay between the processes of chemical differentiation at the Earth’s near surface and the dynamics of mixing in the mantle system variably work to create and destroy the geochemical record of the Earth’s past. Two apparently incompatible conceptual models of whole-Earth behaviour ...
GLG101online_08A_Metamorphism_MCC_Leighty
... As a distance learning student, you need to explore and understand the content more independently than in a traditional class. As always, I will help guide you through this learning adventure. Remember, email Dr. Bob if you have any questions about today’s lecture ([email protected]). Le ...
... As a distance learning student, you need to explore and understand the content more independently than in a traditional class. As always, I will help guide you through this learning adventure. Remember, email Dr. Bob if you have any questions about today’s lecture ([email protected]). Le ...
Geology - Archean Environment: The habitat of early life.
... under which the mineral assemblages equilibrated. Orogenic systems occur along convergent plate margins, either at subducting margins, such as the accretionary orogens around the Pacific rim, or those that have become collision zones, such as the Himalaya-Tibet system, in which the collision is supe ...
... under which the mineral assemblages equilibrated. Orogenic systems occur along convergent plate margins, either at subducting margins, such as the accretionary orogens around the Pacific rim, or those that have become collision zones, such as the Himalaya-Tibet system, in which the collision is supe ...
Sample Midterm/Final
... sea floor spreading will cease because the asthenosphere convection will shut down d the Juan de Fuca spreading ridge will not be subducted under the North American plate e. none of the above answers are correct because the Juan de Fuca spreading ridge is off the coast of Africa. 29. Transform plate ...
... sea floor spreading will cease because the asthenosphere convection will shut down d the Juan de Fuca spreading ridge will not be subducted under the North American plate e. none of the above answers are correct because the Juan de Fuca spreading ridge is off the coast of Africa. 29. Transform plate ...
Calcium isotopic composition of mantle xenoliths and minerals from
... in the upper mantle. Huang et al. (2010) observed large offsets in D44/40Ca (up to 0.75‰) between opx and cpx from peridotite xenoliths. Such large inter-mineral Ca isotopic fractionation could be attributed to the differences in Ca– O bond length between cpx and opx. Based on firstprinciples calculati ...
... in the upper mantle. Huang et al. (2010) observed large offsets in D44/40Ca (up to 0.75‰) between opx and cpx from peridotite xenoliths. Such large inter-mineral Ca isotopic fractionation could be attributed to the differences in Ca– O bond length between cpx and opx. Based on firstprinciples calculati ...
Practice Quiz for Ch. 15 Multiple Choice Identify the choice that best
... ____ 27. Tectonic plates float on a sea of lava or molten rock. ____ 28. A subduction zone is associated with a transform fault. ____ 29. The United States, Canada, Russia, South Africa, and Australia supply most of the nonrenewable mineral resources used by modern societies. ____ 30. Nanotechnology ...
... ____ 27. Tectonic plates float on a sea of lava or molten rock. ____ 28. A subduction zone is associated with a transform fault. ____ 29. The United States, Canada, Russia, South Africa, and Australia supply most of the nonrenewable mineral resources used by modern societies. ____ 30. Nanotechnology ...
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 ...
OPAQUE OXIDES IN SOME ROCKS OF THE BASEMENT
... with both olivine and augite, but are free of ex-solution intergrowths with other iron oxides. The chalcopyrite in parts replacessome of the pyrrhotite, crystals of which do not exceed0.12X0.35 mm. in size. Rare, small particles of a hard and creamy-white mineral, much more brightly reflecting than ...
... with both olivine and augite, but are free of ex-solution intergrowths with other iron oxides. The chalcopyrite in parts replacessome of the pyrrhotite, crystals of which do not exceed0.12X0.35 mm. in size. Rare, small particles of a hard and creamy-white mineral, much more brightly reflecting than ...
Whole-mantle convection with tectonic plates preserves
... recycled9, 10, and the timing of incorporation into the convecting mantle11, 12. Suggested recycled components have included lower continental crust11, sub-continental lithospheric mantle10, 11, 13, altered ocean crust ± pelagic sediments6, and subduction modified mantle9, as well as material from l ...
... recycled9, 10, and the timing of incorporation into the convecting mantle11, 12. Suggested recycled components have included lower continental crust11, sub-continental lithospheric mantle10, 11, 13, altered ocean crust ± pelagic sediments6, and subduction modified mantle9, as well as material from l ...
Lithosphere, Asthenosphere, and Perisphere
... Ironically, the LVZ is most pronounced under hotspots and continental rifts, regions that provide trace element enriched basalts. The concept of a depleted the base of the elastic, or strong,lithosphereis closer asthenosphere is now firmly embedded in the to 550ø-600øC [De Rito et al., 1986; McNutt, ...
... Ironically, the LVZ is most pronounced under hotspots and continental rifts, regions that provide trace element enriched basalts. The concept of a depleted the base of the elastic, or strong,lithosphereis closer asthenosphere is now firmly embedded in the to 550ø-600øC [De Rito et al., 1986; McNutt, ...
emplacement of viscous mushes in the jinchuan ultramafic
... The Jinchuan ultramafic intrusion in western China has an elongate surface expression of about 6000 by 350 meters. It is one of several mafic–ultramafic intrusions found in the fault-bounded Longshoushan uplifted terrane, of Proterozoic age, located along the southwestern edge of the Sino-Korea plat ...
... The Jinchuan ultramafic intrusion in western China has an elongate surface expression of about 6000 by 350 meters. It is one of several mafic–ultramafic intrusions found in the fault-bounded Longshoushan uplifted terrane, of Proterozoic age, located along the southwestern edge of the Sino-Korea plat ...
The thermochemical structure and evolution of Earth`s mantle
... behaviour (e.g. Moresi & Solomatov 1998; Tackley 2000b; c), with essentially rigid plates separated by passive spreading centres and `subduction zones’ that form and evolve naturally with the convection. However, the obtained `subduction zones’ are double-sided (symmetric) and therefore only a crude ...
... behaviour (e.g. Moresi & Solomatov 1998; Tackley 2000b; c), with essentially rigid plates separated by passive spreading centres and `subduction zones’ that form and evolve naturally with the convection. However, the obtained `subduction zones’ are double-sided (symmetric) and therefore only a crude ...
Basalt
Basalt (pronounced /bəˈsɔːlt/, /ˈbæsɒlt/, /ˈbæsɔːlt/, or /ˈbeɪsɔːlt/)is a common extrusive igneous (volcanic) rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon. Flood basalt describes the formation in a series of lava basalt flows.