- BIROn - Birkbeck Institutional Research Online
... lithosphere within western and central Europe occurred as a response to the collisional coupling of the Alpine and Pyrenean orogens with their forelands (Ziegler et al., 1995; Dèzes et al., 2004). Throughout the Tertiary there was a gradual shift of compressional tectonic activity away from the fore ...
... lithosphere within western and central Europe occurred as a response to the collisional coupling of the Alpine and Pyrenean orogens with their forelands (Ziegler et al., 1995; Dèzes et al., 2004). Throughout the Tertiary there was a gradual shift of compressional tectonic activity away from the fore ...
Rheology and Tectonic Significance of Serpentinite
... plane (parallel to the c-axis), which leads to a low isotropic P-wave velocity (Vp) (e.g. Bezacier et al. 2010). Similarly, the shear modulus (ratio of shear stress to shear strain) parallel to the basal plane is very low. Thus, where a strong LPO arises owing to deformation, the elastic anisotropy ...
... plane (parallel to the c-axis), which leads to a low isotropic P-wave velocity (Vp) (e.g. Bezacier et al. 2010). Similarly, the shear modulus (ratio of shear stress to shear strain) parallel to the basal plane is very low. Thus, where a strong LPO arises owing to deformation, the elastic anisotropy ...
Grand Challenges in Geodynamics
... Geodynamics occupies a unique position in the solid Earth Sciences. First and foremost, it is primarily concerned with the dynamical processes that affect the Earth, especially within its interior but also at its surface. Geodynamics is also applied to the interiors and surfaces of other terrestrial ...
... Geodynamics occupies a unique position in the solid Earth Sciences. First and foremost, it is primarily concerned with the dynamical processes that affect the Earth, especially within its interior but also at its surface. Geodynamics is also applied to the interiors and surfaces of other terrestrial ...
Primitive off-rift basalts from Iceland and Jan Mayen: Os
... the Iceland plume is clearly dispersed in the shallow upper mantle, as shown by the incompatible trace element (ITE) enriched signature of Atlantic mid-ocean ridge basalts (MORB) progressively decreasing away from Iceland along the MAR (e.g., Schilling, 1973). The geochemical signatures of Icelandic ...
... the Iceland plume is clearly dispersed in the shallow upper mantle, as shown by the incompatible trace element (ITE) enriched signature of Atlantic mid-ocean ridge basalts (MORB) progressively decreasing away from Iceland along the MAR (e.g., Schilling, 1973). The geochemical signatures of Icelandic ...
Introduction to Geology - Research at UVU
... d. Magma formation at mid-ocean ridges and hotspots i. Melting mid ocean ridges and hotspots 1) Magma forms by Decompression melting. In decompression melting, hot mantle rock rises towards surface. As it moves upwards it remains relatively hot but experiences greatly reduced pressure. Reduction in ...
... d. Magma formation at mid-ocean ridges and hotspots i. Melting mid ocean ridges and hotspots 1) Magma forms by Decompression melting. In decompression melting, hot mantle rock rises towards surface. As it moves upwards it remains relatively hot but experiences greatly reduced pressure. Reduction in ...
Linking rift propagation barriers to excess magmatism at volcanic
... In agreement with observations from the North and South Atlantic, and as imposed by the model’s boundary conditions, break-up in the model occurs via rift propagation (Figs. 2B and 2C). In the same manner, the area affected by decompression melting (between 65 km and 15 km depth beneath the rift cen ...
... In agreement with observations from the North and South Atlantic, and as imposed by the model’s boundary conditions, break-up in the model occurs via rift propagation (Figs. 2B and 2C). In the same manner, the area affected by decompression melting (between 65 km and 15 km depth beneath the rift cen ...
Crustal geophysical research helps constrain the nature of mantle
... passively beneath a spreading center, and arc volcanism is widely accepted to be the remnant of melts originating within the mantle wedge by water expelled from the dehydrating subducting slab at convergent margins, hotspot magmatism can occur nearly anywhere on Earth (Figure 1). The most widely acc ...
... passively beneath a spreading center, and arc volcanism is widely accepted to be the remnant of melts originating within the mantle wedge by water expelled from the dehydrating subducting slab at convergent margins, hotspot magmatism can occur nearly anywhere on Earth (Figure 1). The most widely acc ...
Mantle Dynamics in Mars and Venus
... from below. The Rayleigh numbers of all the cases are approximately 100 times the critical Rayleigh numbers for the onset of convection. Cylindrical plumes are the prominent form of upwelling in the models independent of the surface boundary conditi6n so long as sufficient heat derives from the core ...
... from below. The Rayleigh numbers of all the cases are approximately 100 times the critical Rayleigh numbers for the onset of convection. Cylindrical plumes are the prominent form of upwelling in the models independent of the surface boundary conditi6n so long as sufficient heat derives from the core ...
Lithium Isotope Variations in Ocean Island
... generally appears to be controlled by processes such as magma generation and crust formation, mantle convection and material recycling, as well as metasomatism, the relative contribution of these processes to the heterogeneity of the mantle is still debated. Combined studies of ocean island basalts ...
... generally appears to be controlled by processes such as magma generation and crust formation, mantle convection and material recycling, as well as metasomatism, the relative contribution of these processes to the heterogeneity of the mantle is still debated. Combined studies of ocean island basalts ...
Two Views of the Moon's Composition posted April 3, 2007
... So, the crust has a high concentration of Al2O3 and the mantle has a small concentration. How much does that average out to? Part of the answer is "Anything you want it to," because of the numerous uncertainties in adding up the contributions from different sources. John Longhi uses a mass balance c ...
... So, the crust has a high concentration of Al2O3 and the mantle has a small concentration. How much does that average out to? Part of the answer is "Anything you want it to," because of the numerous uncertainties in adding up the contributions from different sources. John Longhi uses a mass balance c ...
Geophysical Journal International
... The Zagros orogen resulted from the long-lived NE-dipping subduction of the Neotethys Ocean, lasting from Late Cretaceous to Neogene, culminating with the continental collision between Arabia and Eurasia (e.g. Agard et al. 2011; Vergés et al. 2011; Mouthereau et al. 2012; McQuarrie & van Hinsbergen ...
... The Zagros orogen resulted from the long-lived NE-dipping subduction of the Neotethys Ocean, lasting from Late Cretaceous to Neogene, culminating with the continental collision between Arabia and Eurasia (e.g. Agard et al. 2011; Vergés et al. 2011; Mouthereau et al. 2012; McQuarrie & van Hinsbergen ...
JBES-Vol5No6-p338-344 - International network for natural
... J. Bio. & Env. Sci. 2014 chondrite normalized by (Taylor and McLennan, 1985) and negative anomalies and certain of Rb, Ni, Sr, Zr and P, as well as anomalies positive Tb, La, Ba, Ce show particular that of alkaline granitoid is robust and can melt or partial melting of the lower continental crust a ...
... J. Bio. & Env. Sci. 2014 chondrite normalized by (Taylor and McLennan, 1985) and negative anomalies and certain of Rb, Ni, Sr, Zr and P, as well as anomalies positive Tb, La, Ba, Ce show particular that of alkaline granitoid is robust and can melt or partial melting of the lower continental crust a ...
Three Dimensional Electrical Structure of the Crust and Upper
... Three Dimensional Electrical Structure of the Crust and Upper Mantle in Ordos Block and Adjacent Area: Evidence of Regional Lithospheric ...
... Three Dimensional Electrical Structure of the Crust and Upper Mantle in Ordos Block and Adjacent Area: Evidence of Regional Lithospheric ...
Volcanoes and Igneous Activity Earth
... Island arcs Where two ocean plates converge and one is subducted beneath the other Volcanic island arcs result from the steady subduction of oceanic lithosphere ...
... Island arcs Where two ocean plates converge and one is subducted beneath the other Volcanic island arcs result from the steady subduction of oceanic lithosphere ...
Chapter 20 The Precambrian Record
... due to heat from accretion, impacts and radioactive decay from the interior. 16. The composition of the Earth’s first crust was __________ , as indicated by the presence of very old Archean lavas called komatiites. 17. Intermediate to felsic magmas that formed the Earth’s earliest continental crust ...
... due to heat from accretion, impacts and radioactive decay from the interior. 16. The composition of the Earth’s first crust was __________ , as indicated by the presence of very old Archean lavas called komatiites. 17. Intermediate to felsic magmas that formed the Earth’s earliest continental crust ...
Module 2_Excel - Scholar Commons
... crust and oceanic crust. Beneath the crust is the mantle, which makes up the largest volume of the whole Earth by far and consists of an upper and lower mantle. Finally, the core is composed of an outer core and an inner core. The differences in chemical composition also mean that each layer has a v ...
... crust and oceanic crust. Beneath the crust is the mantle, which makes up the largest volume of the whole Earth by far and consists of an upper and lower mantle. Finally, the core is composed of an outer core and an inner core. The differences in chemical composition also mean that each layer has a v ...
Hotspots and Melting Anomalies - Earth and Environmental Sciences
... indicates the melting of mantle peridotite, a process that also produces mid-oceanic ridge volcanism. Yet, geochemical differences between mid-ocean ridge basalts (MORB) and hotspot basalts occur and are particularly evident in isotope ratios (Schilling, 1971; Hart et al., 1973; Schilling, 1973). Th ...
... indicates the melting of mantle peridotite, a process that also produces mid-oceanic ridge volcanism. Yet, geochemical differences between mid-ocean ridge basalts (MORB) and hotspot basalts occur and are particularly evident in isotope ratios (Schilling, 1971; Hart et al., 1973; Schilling, 1973). Th ...
Terrestrial planet evolution in the stagnant
... mode of convection with strongly temperature-dependent viscosity. Given considerable uncertainty surrounding the dependency of mantle rheology on pressure, we choose to focus on the end-member case of pressure-independent potential viscosity, where viscosity does not change with depth along an adiab ...
... mode of convection with strongly temperature-dependent viscosity. Given considerable uncertainty surrounding the dependency of mantle rheology on pressure, we choose to focus on the end-member case of pressure-independent potential viscosity, where viscosity does not change with depth along an adiab ...
Basin processes
... It is debated if heating and magmatic processes cause rifting or if rifting processes cause magmatic activity. However, rifting is always accompanied by magmatic intrusion into the crust and volcanism at the surface, although usually considered a secondary process. The stretching factor in rift zone ...
... It is debated if heating and magmatic processes cause rifting or if rifting processes cause magmatic activity. However, rifting is always accompanied by magmatic intrusion into the crust and volcanism at the surface, although usually considered a secondary process. The stretching factor in rift zone ...
Thermal structure of the shallow upper mantle beneath Italy and
... the non-linear inversion of surface wave in the Western Mediterranean area by Panza et al. (2007a) and Panza and Raykova (2008), in which the lithosphere–asthenosphere velocity structure is reconstructed to depths of about 300 km for 125 cells, each with size 1°× 1° (Fig. 1b). The obtained 125 repre ...
... the non-linear inversion of surface wave in the Western Mediterranean area by Panza et al. (2007a) and Panza and Raykova (2008), in which the lithosphere–asthenosphere velocity structure is reconstructed to depths of about 300 km for 125 cells, each with size 1°× 1° (Fig. 1b). The obtained 125 repre ...
Plate Tectonics - ESL Consulting Services
... addressed. (Editing for conventions should demonstrate command of Language standards 1–3 up to and including grade 8.) 6. Use technology, including the Internet, to produce and publish writing and present the relationships between information and ideas efficiently as well as to interact and collabor ...
... addressed. (Editing for conventions should demonstrate command of Language standards 1–3 up to and including grade 8.) 6. Use technology, including the Internet, to produce and publish writing and present the relationships between information and ideas efficiently as well as to interact and collabor ...
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 ...
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.