Continental crust generated in oceanic arcs
... oceanic crust that originally formed above the Galápagos mantle plume. We also find that seismic P-waves travel through the crust at velocities intermediate between those typically observed for oceanic and continental crust. We develop a continentality index to quantitatively correlate geochemical c ...
... oceanic crust that originally formed above the Galápagos mantle plume. We also find that seismic P-waves travel through the crust at velocities intermediate between those typically observed for oceanic and continental crust. We develop a continentality index to quantitatively correlate geochemical c ...
IM_chapter5 Volcanoes
... eruptions occur along mid-oceanic ridges or their extensions onto land. ...
... eruptions occur along mid-oceanic ridges or their extensions onto land. ...
MagmastoragebeneathAxialvolcano on the Juan de Fuca mid
... (3D) tomographic inversion of the travel-time data, starting with the 1D model, was performed to determine a more realistic crustal structure. The ®nal structure derived from the full set of Pg travel times reduced the travel-time mis®t to 0.089 s. Chequerboard resolution tests demonstrate that this ...
... (3D) tomographic inversion of the travel-time data, starting with the 1D model, was performed to determine a more realistic crustal structure. The ®nal structure derived from the full set of Pg travel times reduced the travel-time mis®t to 0.089 s. Chequerboard resolution tests demonstrate that this ...
Topography and geoid due to lithospheric mass anomalies
... 100 Ma is associated with lithospheric processes, one should conclude that no dynamic topography is observed (Colin & Fleitout 1990). Even if this flattening is due to deep-mantle effects, only some 500 m peak-to-peak topography can be associated with deep circulation effects (Cazenave & Lago 1991). ...
... 100 Ma is associated with lithospheric processes, one should conclude that no dynamic topography is observed (Colin & Fleitout 1990). Even if this flattening is due to deep-mantle effects, only some 500 m peak-to-peak topography can be associated with deep circulation effects (Cazenave & Lago 1991). ...
Fluid release from the subducted Cocos plate and partial melting of
... subduction related fluid release and melt production, magnetotelluric (MT) measurements were carried out in southern Mexico along two coast to coast profiles. The conductivity-depth distribution was obtained by simultaneous two-dimensional inversion of the transverse magnetic and transverse electric ...
... subduction related fluid release and melt production, magnetotelluric (MT) measurements were carried out in southern Mexico along two coast to coast profiles. The conductivity-depth distribution was obtained by simultaneous two-dimensional inversion of the transverse magnetic and transverse electric ...
A Primer
... manifestation, i.e., the top thermal boundary layer, of mantle convection. We review how simple convection pertains to plate formation, regarding the aspect ratio of convection cells; the forces that drive convection; and how internal heating and temperature-dependent viscosity affect convection. We ...
... manifestation, i.e., the top thermal boundary layer, of mantle convection. We review how simple convection pertains to plate formation, regarding the aspect ratio of convection cells; the forces that drive convection; and how internal heating and temperature-dependent viscosity affect convection. We ...
The Relation Between Mantle Dynamics and Plate Tectonics: A Primer
... manifestation, i.e., the top thermal boundary layer, of mantle convection. We review how simple convection pertains to plate formation, regarding the aspect ratio of convection cells; the forces that drive convection; and how internal heating and temperature-dependent viscosity affect convection. We ...
... manifestation, i.e., the top thermal boundary layer, of mantle convection. We review how simple convection pertains to plate formation, regarding the aspect ratio of convection cells; the forces that drive convection; and how internal heating and temperature-dependent viscosity affect convection. We ...
the origin of the strjugsskarð andesite, skagi peninsula, north
... Based on the results presented above, I propose a physical model for mixing similar to that of Meganck (2004). Figure 7 shows a cross-section of a PUB magma chamber aligned in such a way that it could both erupt in Vatnsdalsfjall and also intrude (as a propagating dike) a zoned silicic magma chamber ...
... Based on the results presented above, I propose a physical model for mixing similar to that of Meganck (2004). Figure 7 shows a cross-section of a PUB magma chamber aligned in such a way that it could both erupt in Vatnsdalsfjall and also intrude (as a propagating dike) a zoned silicic magma chamber ...
Velocity increase in the uppermost oceanic crust of subducting
... corresponding well with the P- and S-wave velocities in the oceanic crust. Thus, trapped seismic waves are considered as guided waves propagating along the lowvelocity oceanic crust. This indicates that the study of trapped seismic waves potentially allows us to investigate the seismological structu ...
... corresponding well with the P- and S-wave velocities in the oceanic crust. Thus, trapped seismic waves are considered as guided waves propagating along the lowvelocity oceanic crust. This indicates that the study of trapped seismic waves potentially allows us to investigate the seismological structu ...
MANTLE GEOPHYSICAL OBSERVATIONS AND MANTLE DYNAMICS and the
... During the time that seafloor spreading was being recognized as the surface expression of a convecting Earth, hotspots were also being attributed to mantle processes, separate from, but consistent with, the plate tectonic paradigm. Wilson [1963] introduced the concept that the age progression along ...
... During the time that seafloor spreading was being recognized as the surface expression of a convecting Earth, hotspots were also being attributed to mantle processes, separate from, but consistent with, the plate tectonic paradigm. Wilson [1963] introduced the concept that the age progression along ...
Thermal modelling of the Laramide orogeny: testing the £at
... temperatures of V700^750‡C are attained for depths less than 150 km. In short, it appears that the subducting oceanic lithosphere becomes largely anhydrous once it has been heated above 600^700‡C. If the subducting slab is heated to these temperatures before penetrating the asthenospheric wedge, lit ...
... temperatures of V700^750‡C are attained for depths less than 150 km. In short, it appears that the subducting oceanic lithosphere becomes largely anhydrous once it has been heated above 600^700‡C. If the subducting slab is heated to these temperatures before penetrating the asthenospheric wedge, lit ...
Geology of Greenland Survey Bulletin 177, 89-95
... oceanic crust was both hotter and thicker than at present (Sleep & Windley, 1982; Bickle, 1986) due to a steep geothermal gradient in the oceanic regions. The common assumption that the Archaean oceanic crust was on the average much more short lived than today (due to vigorous production of mantle-d ...
... oceanic crust was both hotter and thicker than at present (Sleep & Windley, 1982; Bickle, 1986) due to a steep geothermal gradient in the oceanic regions. The common assumption that the Archaean oceanic crust was on the average much more short lived than today (due to vigorous production of mantle-d ...
Continental hyperextension, mantle exhumation and thin oceanic
... [Shillington et al., 2006; Van Avendonk et al., 2006]. Both of these margins have been sampled by drilling: at the Newfoundland margin by Ocean Drilling Program (ODP) leg 210 (Figure 1a inset) [Tucholke et al., 2004] and at the Iberia margin by ODP legs 149 and 173 (Figures 1b and 1c) [Sawyer et al. ...
... [Shillington et al., 2006; Van Avendonk et al., 2006]. Both of these margins have been sampled by drilling: at the Newfoundland margin by Ocean Drilling Program (ODP) leg 210 (Figure 1a inset) [Tucholke et al., 2004] and at the Iberia margin by ODP legs 149 and 173 (Figures 1b and 1c) [Sawyer et al. ...
- Wiley Online Library
... [Shillington et al., 2006; Van Avendonk et al., 2006]. Both of these margins have been sampled by drilling: at the Newfoundland margin by Ocean Drilling Program (ODP) leg 210 (Figure 1a inset) [Tucholke et al., 2004] and at the Iberia margin by ODP legs 149 and 173 (Figures 1b and 1c) [Sawyer et al. ...
... [Shillington et al., 2006; Van Avendonk et al., 2006]. Both of these margins have been sampled by drilling: at the Newfoundland margin by Ocean Drilling Program (ODP) leg 210 (Figure 1a inset) [Tucholke et al., 2004] and at the Iberia margin by ODP legs 149 and 173 (Figures 1b and 1c) [Sawyer et al. ...
Assignment 2. Locating plate boundaries on Trafalmador.
... •Oceanic ridges display a linear pattern of earthquakes, all of which have relatively shallow foci. •If deep or intermediate earthquakes lie parallel to the band of shallow earthquakes, it is not a ridge, it is a trench. •Transform faults displace the oceanic ridge and these faults are also characte ...
... •Oceanic ridges display a linear pattern of earthquakes, all of which have relatively shallow foci. •If deep or intermediate earthquakes lie parallel to the band of shallow earthquakes, it is not a ridge, it is a trench. •Transform faults displace the oceanic ridge and these faults are also characte ...
ERSC 1P92 Assignment 2. Locating plate boundaries on
... •Oceanic ridges display a linear pattern of earthquakes, all of which have relatively shallow foci. •If deep or intermediate earthquakes lie parallel to the band of shallow earthquakes, it is not a ridge, it is a trench. •Transform faults displace the oceanic ridge and these faults are also characte ...
... •Oceanic ridges display a linear pattern of earthquakes, all of which have relatively shallow foci. •If deep or intermediate earthquakes lie parallel to the band of shallow earthquakes, it is not a ridge, it is a trench. •Transform faults displace the oceanic ridge and these faults are also characte ...
Assignment 5. Locating plate boundaries on Trafalmador.
... •Oceanic ridges display a linear pattern of earthquakes, all of which have relatively shallow foci. •If deep or intermediate earthquakes lie parallel to the band of shallow earthquakes, it is not a ridge, it is a trench. •Transform faults displace the oceanic ridge and these faults are also characte ...
... •Oceanic ridges display a linear pattern of earthquakes, all of which have relatively shallow foci. •If deep or intermediate earthquakes lie parallel to the band of shallow earthquakes, it is not a ridge, it is a trench. •Transform faults displace the oceanic ridge and these faults are also characte ...
Introduction to Seismology: The wave equation and body waves
... confined to Earth’s crust. Analysis of data from the Southern California Seismic Network for earthquake magnitude and locations falls into this category. Surface waves are not prominent although they can sometimes be seen at very short periods. 2. Regional seismology studies examine waveforms from b ...
... confined to Earth’s crust. Analysis of data from the Southern California Seismic Network for earthquake magnitude and locations falls into this category. Surface waves are not prominent although they can sometimes be seen at very short periods. 2. Regional seismology studies examine waveforms from b ...
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.