`emplacement` of an ophiolite?
... lithosphere, which becomes an ophiolite when incorporated into continental margins through a complex process known as 'emplacement'. A fundamental problem of ophiolite emplacement is how dense oceanic crust becomes emplaced over less dense material(s) of continental margins or subduction-accretion s ...
... lithosphere, which becomes an ophiolite when incorporated into continental margins through a complex process known as 'emplacement'. A fundamental problem of ophiolite emplacement is how dense oceanic crust becomes emplaced over less dense material(s) of continental margins or subduction-accretion s ...
Hawaii, Boundary Layers and Ambient
... over the years. What is new is that we now know the lateral heterogeneity in each region and this reinforces the importance of Gutenberg’s Region B, which includes the lid and the LVL, for mantle petrology. The negative shear velocity gradient in B implies a superadiabatic temperature gradient to de ...
... over the years. What is new is that we now know the lateral heterogeneity in each region and this reinforces the importance of Gutenberg’s Region B, which includes the lid and the LVL, for mantle petrology. The negative shear velocity gradient in B implies a superadiabatic temperature gradient to de ...
accepted manuscript
... and brought back to the surface. Consequently, if the UHP depth estimates are valid (e.g., Spear, 1993), the HP/UHP rocks can be regarded as passive markers of continental subduction and their P-T-t paths can be used for reconstruction of subduction dynamics and of the conditions at the subduction i ...
... and brought back to the surface. Consequently, if the UHP depth estimates are valid (e.g., Spear, 1993), the HP/UHP rocks can be regarded as passive markers of continental subduction and their P-T-t paths can be used for reconstruction of subduction dynamics and of the conditions at the subduction i ...
Orogens and slabs vs. their direction of subduction
... few centimeters per year remains. This is mainly due to the high speed of the Pacific plate toward the ‘west’ which is not entirely compensated by the other plates which are moving in the opposite or different directions. Ricard et al. Ž1991. show that lateral heterogeneities in the asthenospheric v ...
... few centimeters per year remains. This is mainly due to the high speed of the Pacific plate toward the ‘west’ which is not entirely compensated by the other plates which are moving in the opposite or different directions. Ricard et al. Ž1991. show that lateral heterogeneities in the asthenospheric v ...
Geophysical and Petrological Constraints on Ocean Plate Dynamics
... This thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere rises, melts, and flows away from the ridge axis. In Chapters 2 and 3, I pre ...
... This thesis investigates the formation and subsequent motion of oceanic lithospheric plates through geophysical and petrological methods. Ocean crust and lithosphere forms at mid-ocean ridges as the underlying asthenosphere rises, melts, and flows away from the ridge axis. In Chapters 2 and 3, I pre ...
A trace element perspective on the source of ocean island basalts
... under both garnet (red) and spinel (blue) facies conditions cannot explain the formation of the highly enriched OIB melts. The arrows (downwards and leftwards) in panel b, which applies to all other panels, indicating increasing extent of melting form 0.1 to 10%. The incongruent melting relationship ...
... under both garnet (red) and spinel (blue) facies conditions cannot explain the formation of the highly enriched OIB melts. The arrows (downwards and leftwards) in panel b, which applies to all other panels, indicating increasing extent of melting form 0.1 to 10%. The incongruent melting relationship ...
Seamounts – characteristics, formation, mineral deposits and
... is made to compile the available disparate information and present an overview of seamounts in relation to their type, formation, significance and influence on the marine environment. SEAMOUNTS – DEFINITION The International Hydrographic Organisation (Intergovernmental Oceanographic Commission) defi ...
... is made to compile the available disparate information and present an overview of seamounts in relation to their type, formation, significance and influence on the marine environment. SEAMOUNTS – DEFINITION The International Hydrographic Organisation (Intergovernmental Oceanographic Commission) defi ...
Melt migration beneath mid-ocean ridges
... has yet to be determined and it is still not clear whether the pressure gradient arising from mantle £ow with a viscosity of less than 1021 Pa s is su¤cient to direct melt towards the ridge. The third theory considers the partially molten upper mantle as a reactive, permeable compacting/decompacting ...
... has yet to be determined and it is still not clear whether the pressure gradient arising from mantle £ow with a viscosity of less than 1021 Pa s is su¤cient to direct melt towards the ridge. The third theory considers the partially molten upper mantle as a reactive, permeable compacting/decompacting ...
as a PDF - Dipartimento di Scienze della Terra
... subduction zones have mostly continental lithosphere in the upper plate and the dip of the first 125 km is mostly constrained by the thickness and shape of the upper continental plate when present, and by the angle of the slab with respect to the convergence direction as previously mentioned. The wes ...
... subduction zones have mostly continental lithosphere in the upper plate and the dip of the first 125 km is mostly constrained by the thickness and shape of the upper continental plate when present, and by the angle of the slab with respect to the convergence direction as previously mentioned. The wes ...
STRIKE-SLIP AND OBLIQUE
... fault, anticlockwise to a sinistral strike-slip fault. They often form an en échelon and overstepping array synthetic to the main fault; they evolve as a sequence of linked displacement surfaces. Their acute angle with the fault points in the direction of the relative sense of movement on the main f ...
... fault, anticlockwise to a sinistral strike-slip fault. They often form an en échelon and overstepping array synthetic to the main fault; they evolve as a sequence of linked displacement surfaces. Their acute angle with the fault points in the direction of the relative sense of movement on the main f ...
Author`s personal copy - Freie Universität Berlin
... (Dewey et al., 1973). However, they lacked crucial information on the size of Alpine Tethys and the precise age of its demise. The gap in knowledge between plate-motion studies and field-based tectonic syntheses was large, primarily because modern structural petrology and geochronology were in their ...
... (Dewey et al., 1973). However, they lacked crucial information on the size of Alpine Tethys and the precise age of its demise. The gap in knowledge between plate-motion studies and field-based tectonic syntheses was large, primarily because modern structural petrology and geochronology were in their ...
Reconciling plate-tectonic reconstructions of Alpine
... (Dewey et al., 1973). However, they lacked crucial information on the size of Alpine Tethys and the precise age of its demise. The gap in knowledge between plate-motion studies and field-based tectonic syntheses was large, primarily because modern structural petrology and geochronology were in their ...
... (Dewey et al., 1973). However, they lacked crucial information on the size of Alpine Tethys and the precise age of its demise. The gap in knowledge between plate-motion studies and field-based tectonic syntheses was large, primarily because modern structural petrology and geochronology were in their ...
subduction to strike-slip transitions on plate boundaries
... between an axial belt of strike-slip faults and a largely contractional forearc. To the south, where the edge of continental Pacific Plate has been subducted beneath northeastern South Island, almost all of the late Quaternary plate motion is recorded in the upper plate principally across a distribu ...
... between an axial belt of strike-slip faults and a largely contractional forearc. To the south, where the edge of continental Pacific Plate has been subducted beneath northeastern South Island, almost all of the late Quaternary plate motion is recorded in the upper plate principally across a distribu ...
Resolving the lithosphereasthenosphere boundary with seismic
... Accepted 2011 May 30. Received 2011 May 27; in original form 2011 March 19 ...
... Accepted 2011 May 30. Received 2011 May 27; in original form 2011 March 19 ...
Dynamics of intraoceanic subduction initiation
... Approximately a decade after SSZ ophiolites were formally defined, Stern and Bloomer [1992] pointed out, on the basis of geochemical and thermodynamic arguments, that the process of SSZ ophiolitic crust production appears to be restricted to the first 10 Myr of a subduction zone’s lifetime, and these ...
... Approximately a decade after SSZ ophiolites were formally defined, Stern and Bloomer [1992] pointed out, on the basis of geochemical and thermodynamic arguments, that the process of SSZ ophiolitic crust production appears to be restricted to the first 10 Myr of a subduction zone’s lifetime, and these ...
Flow and melting of a heterogeneous mantle
... driven kinematically by two diverging plates is nearly uniform with depth (Fig. 1e) and approximately equal to the half spreading rate of the plates. The normalized flow function U( P) is therefore equal to one and does not appear in the equivalent equations presented previously [11,12]. Buoyancy as ...
... driven kinematically by two diverging plates is nearly uniform with depth (Fig. 1e) and approximately equal to the half spreading rate of the plates. The normalized flow function U( P) is therefore equal to one and does not appear in the equivalent equations presented previously [11,12]. Buoyancy as ...
Geodynpub_files/Boutelier, Chemenda, 2011
... that the asthenosphere exerts a small shear traction on the base of the lithosphere. This traction can thus be neglected if we focus our interest on the solid interaction of the plates in the subduction zone because the action of such small shear traction on a limited area such as the subduction zon ...
... that the asthenosphere exerts a small shear traction on the base of the lithosphere. This traction can thus be neglected if we focus our interest on the solid interaction of the plates in the subduction zone because the action of such small shear traction on a limited area such as the subduction zon ...
- Wiley Online Library
... [Capitanio et al., 2010]. However, we emphasize that the goal of this work is not to reproduce the tectonic evolution of the Himalayan-Tibetan orogen but to understand the most basic physics behind the development of an evolved orogen. Consequently, the velocity boundary conditions were chosen to be ...
... [Capitanio et al., 2010]. However, we emphasize that the goal of this work is not to reproduce the tectonic evolution of the Himalayan-Tibetan orogen but to understand the most basic physics behind the development of an evolved orogen. Consequently, the velocity boundary conditions were chosen to be ...
Wrench faults down to the asthenosphere
... partially melted, strain remains localized (although less efficiently) in transcurrent shear zones. Seismic profiling as well as seismic tomography and magnetotelluric soundings provide strong argument in favor of major wrench faults crosscutting the Moho and deforming the upper mantle. Pn velocity ...
... partially melted, strain remains localized (although less efficiently) in transcurrent shear zones. Seismic profiling as well as seismic tomography and magnetotelluric soundings provide strong argument in favor of major wrench faults crosscutting the Moho and deforming the upper mantle. Pn velocity ...
poster technical sessions
... Shale gas occurs in mudstones with common characteristics including a minimum TOC buried to depths sufficient to achieve a certain thermal maturity. Various mudstones around the globe differ in thickness and regional extent but these characteristic are often not the most important in controlling eco ...
... Shale gas occurs in mudstones with common characteristics including a minimum TOC buried to depths sufficient to achieve a certain thermal maturity. Various mudstones around the globe differ in thickness and regional extent but these characteristic are often not the most important in controlling eco ...
Neotectonic and Paleoseismic Onshore-Offshore integrated study of the Carboneras Fault (Eastern
... with a N045º-N050º orientation (Fig. 2.3a) across the province of Almería (SE Spain). The fault zone width varies between a few hundred metres and about 2 km and is formed by overstepping and “en-echelon” fault traces. After analyzing the whole length of the emerged fault with aerial photos and fiel ...
... with a N045º-N050º orientation (Fig. 2.3a) across the province of Almería (SE Spain). The fault zone width varies between a few hundred metres and about 2 km and is formed by overstepping and “en-echelon” fault traces. After analyzing the whole length of the emerged fault with aerial photos and fiel ...
Plume heads, continental lithosphere, flood
... km . Since other covergence regions give the expected fast velocity signal it appears that resolution is not the problem. The above anomalous regions also do not have the high geoid signals associated with some other subduction zones . The results around NZ-Tonga-Fiji, indicat. ing a broad region of ...
... km . Since other covergence regions give the expected fast velocity signal it appears that resolution is not the problem. The above anomalous regions also do not have the high geoid signals associated with some other subduction zones . The results around NZ-Tonga-Fiji, indicat. ing a broad region of ...
a short story about the geological history of the pamir
... earthquakes occur mostly in a narrow zone not more than 30 km thick (Isacks and Barazangi, 1977) but emerge from depths between 150 and 300 km. This seems to imply a slablike body of presumably cold material (Billington et al., 1977; Roecker et al., 1980) with a thickness of 20-25 km underthrust ben ...
... earthquakes occur mostly in a narrow zone not more than 30 km thick (Isacks and Barazangi, 1977) but emerge from depths between 150 and 300 km. This seems to imply a slablike body of presumably cold material (Billington et al., 1977; Roecker et al., 1980) with a thickness of 20-25 km underthrust ben ...
Mid-ocean ridges
... seafloor spreading at half rates of 1- 10 cm yr.- I Since the size of the Earth is essentially constant, new lithosphere can only be created at mid-oceanic ridges if an equivalent amount of material is consumed elsewhere, at subduction zones (Part 3). Throughout geological time, a succession of ocea ...
... seafloor spreading at half rates of 1- 10 cm yr.- I Since the size of the Earth is essentially constant, new lithosphere can only be created at mid-oceanic ridges if an equivalent amount of material is consumed elsewhere, at subduction zones (Part 3). Throughout geological time, a succession of ocea ...
The Volume and Composition of Melt Generated
... impossible for magma to reach the surface at temperatures greater than about 1200°C? Geophysical and geochemical implications of this observation have, to our knowledge, never been fully explored, even though they could provide important constraints on temperature distribution in the mantle and on t ...
... impossible for magma to reach the surface at temperatures greater than about 1200°C? Geophysical and geochemical implications of this observation have, to our knowledge, never been fully explored, even though they could provide important constraints on temperature distribution in the mantle and on t ...