Breakthrough the Discontinuity: 21st Century Mohole
... Three sites in the Pacific Ocean meet the criteria for the Mohole; 1) the region around Site 1256, 2) the eastern edge of the north Hawaiian arch, and 3) the eastern Pacific plate off Mexico. No site fits all criteria, but all will be feasible to drill to the mantle. There could also be other recogn ...
... Three sites in the Pacific Ocean meet the criteria for the Mohole; 1) the region around Site 1256, 2) the eastern edge of the north Hawaiian arch, and 3) the eastern Pacific plate off Mexico. No site fits all criteria, but all will be feasible to drill to the mantle. There could also be other recogn ...
2.03 Sampling Mantle Heterogeneity through Oceanic Basalts
... from the mantle are not in osmium-isotopic equilibrium with their source is given by the fact that osmium isotopes in MORBs are, on average, significantly more radiogenic than osmium isotopes from oceanic peridotites (see also Figure 9 further below). Although it may be argued that there is no one-t ...
... from the mantle are not in osmium-isotopic equilibrium with their source is given by the fact that osmium isotopes in MORBs are, on average, significantly more radiogenic than osmium isotopes from oceanic peridotites (see also Figure 9 further below). Although it may be argued that there is no one-t ...
Workman, Hart, 2005 - University of Maryland, Department of Geology
... upper mantle depletion came with the classic trace element studies of Johnson et al. [10] and Johnson and Dick [11] on abyssal peridotites, but most of the observed depletion in these peridotites is due to melt extraction during the latest spreading events, so that the composition of the general amb ...
... upper mantle depletion came with the classic trace element studies of Johnson et al. [10] and Johnson and Dick [11] on abyssal peridotites, but most of the observed depletion in these peridotites is due to melt extraction during the latest spreading events, so that the composition of the general amb ...
M44-2002-C24-eng - Publications du gouvernement du Canada
... Syme (1987) defined the fault-bounded Bear Lake structural domain as containing a large portion (4 km by 11 km) of a basalt flow-dominated volcanic edifice topped to the east by a cauldron complex which contains the Cuprus and White Lake VMS deposits (Fig. 1). As a result of their study, a large, ep ...
... Syme (1987) defined the fault-bounded Bear Lake structural domain as containing a large portion (4 km by 11 km) of a basalt flow-dominated volcanic edifice topped to the east by a cauldron complex which contains the Cuprus and White Lake VMS deposits (Fig. 1). As a result of their study, a large, ep ...
Plate Tectonics: GL209 Prof. John Tarney Lecture 5: Subduction
... Subduction Zones are where cool lithospheric plates sink back into the mantle. It takes about 50 my for the ocean lithosphere that formed in the hot (>1000°C) environment at mid-ocean ridges to cool to an equilibrium state and sink to its maximum depth below sea-level. Although there is no universal ...
... Subduction Zones are where cool lithospheric plates sink back into the mantle. It takes about 50 my for the ocean lithosphere that formed in the hot (>1000°C) environment at mid-ocean ridges to cool to an equilibrium state and sink to its maximum depth below sea-level. Although there is no universal ...
Mantle discontinuities beneath the Deccan volcanic
... velocity zone below 200 km were mapped through teleseismic P-wave tomography [14]. This seismic anomaly is seen to link to the Narmada rift and possibly extends further south beneath the Western Ghats, the main effusive phase in the DVP, where the tomograms were not well resolved. Earlier, tomograph ...
... velocity zone below 200 km were mapped through teleseismic P-wave tomography [14]. This seismic anomaly is seen to link to the Narmada rift and possibly extends further south beneath the Western Ghats, the main effusive phase in the DVP, where the tomograms were not well resolved. Earlier, tomograph ...
Constraints on mantle melting and composition and nature of slab
... parental magmas and mantle sources, 2) to constrain thermal conditions of mantle melting, and 3) to estimate the composition of slabderived components. We demonstrate that typical Kamchatkan arc-type magmas originate through 5–14% melting of sources similar or slightly more depleted in HFSE (with up ...
... parental magmas and mantle sources, 2) to constrain thermal conditions of mantle melting, and 3) to estimate the composition of slabderived components. We demonstrate that typical Kamchatkan arc-type magmas originate through 5–14% melting of sources similar or slightly more depleted in HFSE (with up ...
101 - Durham University Community
... bulk Earth. If we assume the PM to be compositionally uniform, we must explain why the mantle source for mid-ocean ridge basalts (MORB) is more depleted both isotopically and in terms of incompatible elements than the mantle source for OIB. By interpreting MORB mantle depletion as resulting from con ...
... bulk Earth. If we assume the PM to be compositionally uniform, we must explain why the mantle source for mid-ocean ridge basalts (MORB) is more depleted both isotopically and in terms of incompatible elements than the mantle source for OIB. By interpreting MORB mantle depletion as resulting from con ...
20 Crystallization, Fractionation and Solidification of Co
... changes in structure of residual melts in spatial and temporal conditions. Slow cooling permits extensive large crystal growth under plutonic magmatic crystallization. As melting and crystallization are reversible processes, different types of phase diagrams are needed to understand how melts crysta ...
... changes in structure of residual melts in spatial and temporal conditions. Slow cooling permits extensive large crystal growth under plutonic magmatic crystallization. As melting and crystallization are reversible processes, different types of phase diagrams are needed to understand how melts crysta ...
Geology of the Cerrillos Area - New Mexico Bureau of Geology
... In Oligocene(?) time uplift and complex folding and faulting occurred during the emplacement of a series of monzonitic stocks, plugs, laccoliths, sills, and dikes. The first intrusion was hornblende monzonite porphyry, the second and third were hornblende-augite monzonite porphyry, and the fourth wa ...
... In Oligocene(?) time uplift and complex folding and faulting occurred during the emplacement of a series of monzonitic stocks, plugs, laccoliths, sills, and dikes. The first intrusion was hornblende monzonite porphyry, the second and third were hornblende-augite monzonite porphyry, and the fourth wa ...
Adakitic magmas: modern analogues of Archaean granitoids
... Ž30–50 ppm. contents are higher than in typical calc-alkaline magmas. Sr contents are high Ž) 300 ppm, until 2000 ppm. and REE show strongly fractionated patterns with very low heavy REE ŽHREE. contents ŽYb F 1.8 ppm, Y F 18 ppm.. Consequently, high SrrY and LarYb ratios are typical and discriminati ...
... Ž30–50 ppm. contents are higher than in typical calc-alkaline magmas. Sr contents are high Ž) 300 ppm, until 2000 ppm. and REE show strongly fractionated patterns with very low heavy REE ŽHREE. contents ŽYb F 1.8 ppm, Y F 18 ppm.. Consequently, high SrrY and LarYb ratios are typical and discriminati ...
Coire Uaigneich
... acid intrusion pre-dated the gabbros it would have exhibited a thermal overprint and the finegrained chilled contact, with its distinctive quartz paramorphs after tridymite, would in all probability have been obliterated. The presence of the quartz paramorphs after tridymite indicate a depth of cove ...
... acid intrusion pre-dated the gabbros it would have exhibited a thermal overprint and the finegrained chilled contact, with its distinctive quartz paramorphs after tridymite, would in all probability have been obliterated. The presence of the quartz paramorphs after tridymite indicate a depth of cove ...
Serpentinites - Elements Magazine
... these modern serpentinites has provided useful inforserpentine-group minerals (chrysotile, lizardite and antigmation for identifying the protoliths of serpentinites in orite)—are present in almost all continents and island arcs. They form large massifs and belts (e.g. the Great Serpentinite ancient ...
... these modern serpentinites has provided useful inforserpentine-group minerals (chrysotile, lizardite and antigmation for identifying the protoliths of serpentinites in orite)—are present in almost all continents and island arcs. They form large massifs and belts (e.g. the Great Serpentinite ancient ...
The landslide
... large lobes of rock debris superpose the glacial morphological surface. Huge solitary blocks of volcanic rocks on the slopes facing Vaigat are evidence of occasional rock falls, some of which may have generated tsunamis. The first published account of a landslide in Greenland is that of Steenstrup ( ...
... large lobes of rock debris superpose the glacial morphological surface. Huge solitary blocks of volcanic rocks on the slopes facing Vaigat are evidence of occasional rock falls, some of which may have generated tsunamis. The first published account of a landslide in Greenland is that of Steenstrup ( ...
Chapter 17. The Other Isotopes
... ages of significant events, such as Moon formation. The isotopes include both those with long half lives, such as rubidium-87- written 87Rb or 87 Rb (half life of 48 .8 billion years), which decays to strontium-87- written 87Sr or 87 Sr- and those that have half lives that are so short that the radi ...
... ages of significant events, such as Moon formation. The isotopes include both those with long half lives, such as rubidium-87- written 87Rb or 87 Rb (half life of 48 .8 billion years), which decays to strontium-87- written 87Sr or 87 Sr- and those that have half lives that are so short that the radi ...
Chapter 18 PowerPoint
... • Magmatic intrusions affect the crust in several ways. Magma can force overlying rock apart and enter the newly formed fissures. Magma can also cause blocks of rock to break off and sink into the magma chamber. Magma can melt the rock into which it intrudes. • Batholiths, stocks, sills, dikes, and ...
... • Magmatic intrusions affect the crust in several ways. Magma can force overlying rock apart and enter the newly formed fissures. Magma can also cause blocks of rock to break off and sink into the magma chamber. Magma can melt the rock into which it intrudes. • Batholiths, stocks, sills, dikes, and ...
ES Chapter 18
... • Magmatic intrusions affect the crust in several ways. Magma can force overlying rock apart and enter the newly formed fissures. Magma can also cause blocks of rock to break off and sink into the magma chamber. Magma can melt the rock into which it intrudes. • Batholiths, stocks, sills, dikes, and ...
... • Magmatic intrusions affect the crust in several ways. Magma can force overlying rock apart and enter the newly formed fissures. Magma can also cause blocks of rock to break off and sink into the magma chamber. Magma can melt the rock into which it intrudes. • Batholiths, stocks, sills, dikes, and ...
Radiogenic Isotope Geochemistry of the Mantle
... the region occupied by the oceanic basalt data is often referred to as the “mantle array”. The second observation is that, although there is overlap, MORB have the lower 87Sr/86Sr ratios and highest εNd than OIB. Variations in radiogenic isotope ratios in basalts result from variations in parent-dau ...
... the region occupied by the oceanic basalt data is often referred to as the “mantle array”. The second observation is that, although there is overlap, MORB have the lower 87Sr/86Sr ratios and highest εNd than OIB. Variations in radiogenic isotope ratios in basalts result from variations in parent-dau ...
Composition of the Oceanic Crust - DukeSpace
... decompression melting, and these melts rise buoyantly to the surface to form a basaltic, rather than serpentinitic, oceanic crust. Approximately 60% of the Earth’s surface consists of oceanic crust (Cogley, 1984), and most of it has formed in this way at divergent plate boundaries called mid-ocean r ...
... decompression melting, and these melts rise buoyantly to the surface to form a basaltic, rather than serpentinitic, oceanic crust. Approximately 60% of the Earth’s surface consists of oceanic crust (Cogley, 1984), and most of it has formed in this way at divergent plate boundaries called mid-ocean r ...
Overview of the Geology of Mount Shasta
... Volcanism and Volcanic Landforms Silicon and oxygen are the two most abundant elements in Earth's crust and mantle. The characteristics of lavas depend so strongly on the abundances of these elements that volcanic rocks are classified according to the amounts of silica (SiO2) that they contain. Lava ...
... Volcanism and Volcanic Landforms Silicon and oxygen are the two most abundant elements in Earth's crust and mantle. The characteristics of lavas depend so strongly on the abundances of these elements that volcanic rocks are classified according to the amounts of silica (SiO2) that they contain. Lava ...
Non-hotspot volcano chains from small
... deformation is characterized by much smaller wavelengths (50-500 km) than that, which are commonly expected for PLI (>1000 km); (2) plume head flattening is asymmetric below intra-plate boundaries, which leads to mechanical decoupling of crust from mantle lithosphere, and to localized faulting at t ...
... deformation is characterized by much smaller wavelengths (50-500 km) than that, which are commonly expected for PLI (>1000 km); (2) plume head flattening is asymmetric below intra-plate boundaries, which leads to mechanical decoupling of crust from mantle lithosphere, and to localized faulting at t ...
PLATE TECTONICS: Lecture 5
... back arc region. In the W. Pacific it is old (Jurassic), cold and dense lithosphere that is subducting - with very steep dip and strong vertical component. Thus extensional conditions in back-arc region. In the E. Pacific, on the other hand, the lithosphere subducting beneath the Andes is young (Ter ...
... back arc region. In the W. Pacific it is old (Jurassic), cold and dense lithosphere that is subducting - with very steep dip and strong vertical component. Thus extensional conditions in back-arc region. In the E. Pacific, on the other hand, the lithosphere subducting beneath the Andes is young (Ter ...
mid-ocean ridge tectonics, volcanism
... y1) a 1–3 km deep rift valley marks the axis, while for fast spreading rates (490 mm y1) the axis is characterized by an elevation of the seafloor of several hundred meters, called an axial high (Figure 2). The rate of magma supply is a second factor that may influence the morphology of mid-ocean ...
... y1) a 1–3 km deep rift valley marks the axis, while for fast spreading rates (490 mm y1) the axis is characterized by an elevation of the seafloor of several hundred meters, called an axial high (Figure 2). The rate of magma supply is a second factor that may influence the morphology of mid-ocean ...
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.