Ghikas et al.IGR2010
... constrain the maximum age of the timing of ophiolite emplacement. Because they contain material from the rift – drift tectonics of the basins prior to their terminal closure, these subophiolitic mélanges can also give us significant clues about the tectonic, sedimentary, and magmatic processes and ...
... constrain the maximum age of the timing of ophiolite emplacement. Because they contain material from the rift – drift tectonics of the basins prior to their terminal closure, these subophiolitic mélanges can also give us significant clues about the tectonic, sedimentary, and magmatic processes and ...
SESSIONE TS1.3 Processi magmatici e metamorfici nella crosta
... We present a geodynamic reconstruction of the Central– Western Mediterranean and neighboring areas during the last 50 Myr, including magmatological and tectonic observations. This area (Fig. 1) was interested by different styles of evolution and polarity of subduction zones influenced by the fragmen ...
... We present a geodynamic reconstruction of the Central– Western Mediterranean and neighboring areas during the last 50 Myr, including magmatological and tectonic observations. This area (Fig. 1) was interested by different styles of evolution and polarity of subduction zones influenced by the fragmen ...
P-and S-wave velocities of the lowermost crustal rocks from the
... Klemperer, 1999; Holbrook et al., 1999), and Izu-Bonin-Mariana (e.g. Kodaira et al., 2007; Suyehiro et al., 1996; Takahashi et al., 2008) arcs. ...
... Klemperer, 1999; Holbrook et al., 1999), and Izu-Bonin-Mariana (e.g. Kodaira et al., 2007; Suyehiro et al., 1996; Takahashi et al., 2008) arcs. ...
The origin of metamorphic core complexes and detachment faults
... faulting, but the faults are relatively small, and they do not penetrate deep into the crust. Below the stress guide, ductile flow relaxes the accumulating elastic stresses, so that lower stress levels are maintained. When the great earthquake occurs, it breaks the stress guide and bites deep into t ...
... faulting, but the faults are relatively small, and they do not penetrate deep into the crust. Below the stress guide, ductile flow relaxes the accumulating elastic stresses, so that lower stress levels are maintained. When the great earthquake occurs, it breaks the stress guide and bites deep into t ...
Second Draft with Art and Photos September 2006
... deeper earthquakes away from the trench. This pattern follows, and helps define, the depths of the subducted slab, which is inclined from the shallow to deep earthquakes. ...
... deeper earthquakes away from the trench. This pattern follows, and helps define, the depths of the subducted slab, which is inclined from the shallow to deep earthquakes. ...
Differential preservation in the geologic record of intraoceanic arc
... Records of ancient intraoceanic arc activity, now preserved in continental suture zones, are commonly used to reconstruct paleogeography and plate motion, and to understand how continental crust is formed, recycled, and maintained through time. However, interpreting tectonic and sedimentary records ...
... Records of ancient intraoceanic arc activity, now preserved in continental suture zones, are commonly used to reconstruct paleogeography and plate motion, and to understand how continental crust is formed, recycled, and maintained through time. However, interpreting tectonic and sedimentary records ...
Bulletin of the Geological Society of Denmark, Vol. 29/1-2, pp. 77-101
... molasse sedimentation and Mesozoic rifting, and a southern area which apparently formed a cratonic block from the Early Proterozoic to the Middle Cretaceous. The whole margin was finally separated from the NW Eiu'opean margin by sea floor spreading in the latest Paleocene to earliest Eocene and now ...
... molasse sedimentation and Mesozoic rifting, and a southern area which apparently formed a cratonic block from the Early Proterozoic to the Middle Cretaceous. The whole margin was finally separated from the NW Eiu'opean margin by sea floor spreading in the latest Paleocene to earliest Eocene and now ...
PDF
... The lower lavas of Troodos are more VAB-like than MORB-like; however, the lower lavas are clearly less HFSE-depleted and LILE-enriched than the upper lavas and hence exhibit an identical chemostratigraphic progression as other SIR ophiolites and the Marianas forearc, which yield lower lavas that mor ...
... The lower lavas of Troodos are more VAB-like than MORB-like; however, the lower lavas are clearly less HFSE-depleted and LILE-enriched than the upper lavas and hence exhibit an identical chemostratigraphic progression as other SIR ophiolites and the Marianas forearc, which yield lower lavas that mor ...
PDF
... cone complex that was active between 2·76 and 1·34 Ma. Basalts were erupted at more than 14 centers scattered over a region 40 km in diameter. Alkali basalt was erupted first, followed by sub-alkaline basalt. Quasi-concentric expansion of eruption centers coinciding with uplift and with decreasing a ...
... cone complex that was active between 2·76 and 1·34 Ma. Basalts were erupted at more than 14 centers scattered over a region 40 km in diameter. Alkali basalt was erupted first, followed by sub-alkaline basalt. Quasi-concentric expansion of eruption centers coinciding with uplift and with decreasing a ...
Oxygen-isotope and trace element constraints on the origins of silica
... xenoliths are hosted by basaltic andesite and are believed to sample the upper portions of the mantle wedge beneath the Luzon arc. The melt inclusions contained in these xenoliths have silica contents up to 63% and Sr/Y ratios up to 250, within the adakitic range. The melt inclusions correspond to ...
... xenoliths are hosted by basaltic andesite and are believed to sample the upper portions of the mantle wedge beneath the Luzon arc. The melt inclusions contained in these xenoliths have silica contents up to 63% and Sr/Y ratios up to 250, within the adakitic range. The melt inclusions correspond to ...
Fall 2012 - Washtenaw Community College
... 5. Identify and locate features using topographic maps. Matched Outcomes 6. Describe basic subatomic particles, atomic mass, atomic number, and ions and their relationship to minerals and Earth materials. Matched Outcomes 7. Identify the structure of the silicon-oxygen tetrahedron and explain the ch ...
... 5. Identify and locate features using topographic maps. Matched Outcomes 6. Describe basic subatomic particles, atomic mass, atomic number, and ions and their relationship to minerals and Earth materials. Matched Outcomes 7. Identify the structure of the silicon-oxygen tetrahedron and explain the ch ...
PDF
... represent a forearc and backarc basin sequence, respectively. These inferences are most simply resolved with a tectonic model whereby the intra-oceanic Kohistan arc evolved over a south-dipping subduction zone, implying that Kohistan and India moved northwards on the same plate, although separated, ...
... represent a forearc and backarc basin sequence, respectively. These inferences are most simply resolved with a tectonic model whereby the intra-oceanic Kohistan arc evolved over a south-dipping subduction zone, implying that Kohistan and India moved northwards on the same plate, although separated, ...
High-Mg# andesitic lavas of the Shisheisky Complex, Northern
... et al. 2002; Kelemen et al. 2003b; Conder 2005). Despite the basic differences between the two models for high-Mg# andesite genesis described earlier, both interpretations imply that high-Mg# andesites are a primary arc magma type that is generated below the crust–mantle boundary under hydrous condi ...
... et al. 2002; Kelemen et al. 2003b; Conder 2005). Despite the basic differences between the two models for high-Mg# andesite genesis described earlier, both interpretations imply that high-Mg# andesites are a primary arc magma type that is generated below the crust–mantle boundary under hydrous condi ...
Workshop Report - Consortium for Ocean Leadership
... mantle sections in ophiolites such as the Trinity and Josephine peridotites provide important opportunities to directly study fluid flow and melt fluxes above a subducting slab that are only now just being exploited. An increasingly large segment of the community working on cratonic mantle xenoliths ...
... mantle sections in ophiolites such as the Trinity and Josephine peridotites provide important opportunities to directly study fluid flow and melt fluxes above a subducting slab that are only now just being exploited. An increasingly large segment of the community working on cratonic mantle xenoliths ...
Dayem, K. E., G. A. Houseman, and P. Molnar (2009), Localization of shear along a lithospheric strength
... 1998]. We examine how such localized strain may develop beneath a fault zone. [3] The deforming Tibetan lithosphere has been described in several ways. In one view, a small number of major faults with large offsets and slip rates separate essentially rigid blocks so that deformation throughout the l ...
... 1998]. We examine how such localized strain may develop beneath a fault zone. [3] The deforming Tibetan lithosphere has been described in several ways. In one view, a small number of major faults with large offsets and slip rates separate essentially rigid blocks so that deformation throughout the l ...
Three lithospheric transects across the Alps and their forelands
... an embayment of the Meliata Ocean into Apulia, the latter is due to the closure of the Alpine Tethys between Apulia and Europe (Haas et al 1995; Stampfli et al. 2001a,b). In view of rather substantial along-strike changes, we chose to construct three transects. A first one (TRANSALP transect VI: sec ...
... an embayment of the Meliata Ocean into Apulia, the latter is due to the closure of the Alpine Tethys between Apulia and Europe (Haas et al 1995; Stampfli et al. 2001a,b). In view of rather substantial along-strike changes, we chose to construct three transects. A first one (TRANSALP transect VI: sec ...
The Tien Shan Early Paleozoic tectonics and geodynamics
... [9] Microcontinent, continental island arc. In the Paleozoic the Tien Shan rocks composed a few tectonic blocks, having an old continental crust and separated by oceanic basins. A continental block of this kind can be ranked as a microcontinent or as a continental island arc, volcanic or nonvolcanic ...
... [9] Microcontinent, continental island arc. In the Paleozoic the Tien Shan rocks composed a few tectonic blocks, having an old continental crust and separated by oceanic basins. A continental block of this kind can be ranked as a microcontinent or as a continental island arc, volcanic or nonvolcanic ...
Superposed Fault Systems of the Southernmost
... Groups (Talladega belt) indicate establishment of a passive margin along the Cambrian trailing edge of this portion of Laurentia. Intrusion of continental slope-rise deposits within the Ashland-Wedowee belt by latest Cambrian(?) to Middle Ordovician arc related plutons was immediately preceded by su ...
... Groups (Talladega belt) indicate establishment of a passive margin along the Cambrian trailing edge of this portion of Laurentia. Intrusion of continental slope-rise deposits within the Ashland-Wedowee belt by latest Cambrian(?) to Middle Ordovician arc related plutons was immediately preceded by su ...
Important Notice
... pairs to estimate empirical Green’s Functions. This thesis is made up of there separate studies. The first is an isotropic application of the ambient-noise tomography method to image crustal structure beneath Hudson Bay. Results show crustal thinning beneath the Bay, allowing us to reject a hypothes ...
... pairs to estimate empirical Green’s Functions. This thesis is made up of there separate studies. The first is an isotropic application of the ambient-noise tomography method to image crustal structure beneath Hudson Bay. Results show crustal thinning beneath the Bay, allowing us to reject a hypothes ...
preview PDF only - California State University Stanislaus
... The first model to explain the tectonic history of the Chortis block invokes large-scale strike-slip motion on the CaymanMotagua-Polochic strike-slip fault system that presently forms the northern edge of the Chortis block (Figs. 1A and 1B). In this model, the Chortis block is detached from its pre– ...
... The first model to explain the tectonic history of the Chortis block invokes large-scale strike-slip motion on the CaymanMotagua-Polochic strike-slip fault system that presently forms the northern edge of the Chortis block (Figs. 1A and 1B). In this model, the Chortis block is detached from its pre– ...
First- and Second-Order Patterns of Stress in the
... horizontal stress orientations to within <_+25ø. Remarkably good correlation is observed between stress orientations deduced from in situ stress measurements and geologic observations made in the upper 1-2 km, well bore breakouts extending to 4-5 km depth and earthquake focal mechanisms to depthsof- ...
... horizontal stress orientations to within <_+25ø. Remarkably good correlation is observed between stress orientations deduced from in situ stress measurements and geologic observations made in the upper 1-2 km, well bore breakouts extending to 4-5 km depth and earthquake focal mechanisms to depthsof- ...
The tonalite–trondhjemite–granodiorite (TTG)
... and modest to absent Eu anomalies but may also be less strongly HREE depleted. These rocks do not represent firstgeneration continental crust: most have unradiogenic Nd and radiogenic 207Pb/204Pb isotopic compositions that require the incorporation of isotopically evolved sources. The GG suite has c ...
... and modest to absent Eu anomalies but may also be less strongly HREE depleted. These rocks do not represent firstgeneration continental crust: most have unradiogenic Nd and radiogenic 207Pb/204Pb isotopic compositions that require the incorporation of isotopically evolved sources. The GG suite has c ...
On Earth`s Mantle Constitution and Structure from Joint Analysis of
... and bulk composition. For this purpose we use the thermodynamic formulation of Stixrude and Lithgow-Bertelloni (2005) with parameters as in Stixrude and Lithgow-Bertelloni (2011). Although Gibbs energy minimization has long been advocated for geophysical problems (e.g., Sobolev and Babeyko 1994; Bin ...
... and bulk composition. For this purpose we use the thermodynamic formulation of Stixrude and Lithgow-Bertelloni (2005) with parameters as in Stixrude and Lithgow-Bertelloni (2011). Although Gibbs energy minimization has long been advocated for geophysical problems (e.g., Sobolev and Babeyko 1994; Bin ...
Crustal structure of central and northern Iceland from analysis of
... We present results from a teleseismic receiver function study of central and northern Iceland, carried out during the period 1995±1998. Data from eight broad-band seismometers installed in the SIL network operated by the Icelandic Meteorological Of®ce were used for analysis. Receiver functions for e ...
... We present results from a teleseismic receiver function study of central and northern Iceland, carried out during the period 1995±1998. Data from eight broad-band seismometers installed in the SIL network operated by the Icelandic Meteorological Of®ce were used for analysis. Receiver functions for e ...
Plate tectonics
Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός ""pertaining to building"") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s.The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.