Crustal and upper mantle structure of southernmost South America
... search of the model space and enabling us to examine alternative local error minima. The vertical and transverse waveforms were used, extending from the P arrival to the surface waves, and the inversion was performed at either 0.005–0.06 Hz (larger events) or 0.02– 0.06 Hz (smaller events). The inve ...
... search of the model space and enabling us to examine alternative local error minima. The vertical and transverse waveforms were used, extending from the P arrival to the surface waves, and the inversion was performed at either 0.005–0.06 Hz (larger events) or 0.02– 0.06 Hz (smaller events). The inve ...
Uppermost mantle structure of the North China Craton: Constraints
... The uppermost mantle is the key area for exchange of heat flux and material convection between the crust and lithospheric mantle. Spatial variations of lithospheric thinning and dynamic processes in the North China Craton could inevitably induce the velocity heterogeneity in the uppermost mantle. In ...
... The uppermost mantle is the key area for exchange of heat flux and material convection between the crust and lithospheric mantle. Spatial variations of lithospheric thinning and dynamic processes in the North China Craton could inevitably induce the velocity heterogeneity in the uppermost mantle. In ...
Lithosphere delamination in continental collisional orogens: A
... slopes are limited by prescribing the maximum stable slope angle “θmax”. In the numerical models, tan(θmax) = 0.1 is applied, which is maintained at each time step by computing an instantaneous mass redistribution in the regions of unstable surface slopes. Our parameter studies indicate that variabi ...
... slopes are limited by prescribing the maximum stable slope angle “θmax”. In the numerical models, tan(θmax) = 0.1 is applied, which is maintained at each time step by computing an instantaneous mass redistribution in the regions of unstable surface slopes. Our parameter studies indicate that variabi ...
(Neoproterozoic-Paleozoic) and plate reconstructions
... structure of Arctida, the reasons and mechanisms of its breakup, the drift trajectories of the continental blocks that composed it. The very existence of oceanic basins that supposedly separated the paleocontinents is uncertain. All these are largely debatable topics, especially the early stages of ...
... structure of Arctida, the reasons and mechanisms of its breakup, the drift trajectories of the continental blocks that composed it. The very existence of oceanic basins that supposedly separated the paleocontinents is uncertain. All these are largely debatable topics, especially the early stages of ...
6 Planetary Interiors - Center for Integrative Planetary Science
... center just about compensates for our overestimate in gravity. Using the single slab model, Jupiter’s central pressure is still underestimated by a factor of ∼ 4, since this planet is very dense near its center (realistic models show that Jupiter’s central pressure is roughly 80 Mbar). An accurate e ...
... center just about compensates for our overestimate in gravity. Using the single slab model, Jupiter’s central pressure is still underestimated by a factor of ∼ 4, since this planet is very dense near its center (realistic models show that Jupiter’s central pressure is roughly 80 Mbar). An accurate e ...
Workman, Hart, 2005 - University of Maryland, Department of Geology
... primitive upper mantle (PUM) coordinate of McDonough and Sun [14]; most regressions intersect the PUM coordinate without forcing, but this treatment becomes appropriate for some regressions with poor correlations (for example, see the Ce–Nd panel in Fig. 2) and we find it necessary for obtaining rob ...
... primitive upper mantle (PUM) coordinate of McDonough and Sun [14]; most regressions intersect the PUM coordinate without forcing, but this treatment becomes appropriate for some regressions with poor correlations (for example, see the Ce–Nd panel in Fig. 2) and we find it necessary for obtaining rob ...
Thermal evolution of the North Atlantic
... the robustness of this inversion scheme. A fractal exponent of 3.0 in the magnetic susceptibility is found suitable, and Curie depths are well constrained by their known depths near the mid-Atlantic ridge. While generally increasing with growing ages, North Atlantic Curie depths show large oscillati ...
... the robustness of this inversion scheme. A fractal exponent of 3.0 in the magnetic susceptibility is found suitable, and Curie depths are well constrained by their known depths near the mid-Atlantic ridge. While generally increasing with growing ages, North Atlantic Curie depths show large oscillati ...
Summary of Research Projects John W. Shervais Department of Geology Professor and Head
... overlying crust was extracted, and its mineralogy and composition reflect the processes that have affected it through time, including melt extraction, fluid phase enrichment, and subsequent interactions with melt derived from lower in the mantle tectosphere. These processes have been frozen in place ...
... overlying crust was extracted, and its mineralogy and composition reflect the processes that have affected it through time, including melt extraction, fluid phase enrichment, and subsequent interactions with melt derived from lower in the mantle tectosphere. These processes have been frozen in place ...
Slab behaviour and its surface expression: new insights
... the subsurface. In both cases, Bouguer and free-air anomalies are the same for the uncompensated stage (Fig. 1b,d). The broad free-air anomalies indicate that isostatic equilibrium is not realized and the Bouguer anomalies reveal the uncompensated mass deficit and mass excess for the two models. Not ...
... the subsurface. In both cases, Bouguer and free-air anomalies are the same for the uncompensated stage (Fig. 1b,d). The broad free-air anomalies indicate that isostatic equilibrium is not realized and the Bouguer anomalies reveal the uncompensated mass deficit and mass excess for the two models. Not ...
Marked Manuscript_GR_RK
... their possible conjugate structure. Here we utilize elastic thickness (Te) and Moho depth data as ...
... their possible conjugate structure. Here we utilize elastic thickness (Te) and Moho depth data as ...
Plate tectonic evolution of the southern margin of
... Orogeny was completed by the collision of Gondwana and Laurussia, whereas the Tethys Ocean formed the embayment between the Eurasian and Gondwanian branches of Pangea. During Late Triassic – Early Jurassic times, several microplates were sutured to the Eurasian margin, closing the Paleotethys Ocean. ...
... Orogeny was completed by the collision of Gondwana and Laurussia, whereas the Tethys Ocean formed the embayment between the Eurasian and Gondwanian branches of Pangea. During Late Triassic – Early Jurassic times, several microplates were sutured to the Eurasian margin, closing the Paleotethys Ocean. ...
A Global View of the Lithosphere-Asthenosphere
... used as chiral initiators of asymmetric autocatalysis. When (S)-3 was used as the chiral trigger, enantioselective addition of i-Pr2Zn to pyrimidine5-carbaldehyde 4 afforded (S)-pyrimidyl alkanol 5 with 95% ee in 96% yield (entry 25). In contrast, the reaction in the presence of (R)-3 gave (R)-alkan ...
... used as chiral initiators of asymmetric autocatalysis. When (S)-3 was used as the chiral trigger, enantioselective addition of i-Pr2Zn to pyrimidine5-carbaldehyde 4 afforded (S)-pyrimidyl alkanol 5 with 95% ee in 96% yield (entry 25). In contrast, the reaction in the presence of (R)-3 gave (R)-alkan ...
gsa today - College of Science
... (summarized in Barker and Dalziel [1983] and Lawver et al. [1995]), because the more we learn about its structure and morphology, the more difficult it is to postulate a simple model to explain its tectonic evolution. Subduction has occurred along the southern South America–Antarctic Peninsula margi ...
... (summarized in Barker and Dalziel [1983] and Lawver et al. [1995]), because the more we learn about its structure and morphology, the more difficult it is to postulate a simple model to explain its tectonic evolution. Subduction has occurred along the southern South America–Antarctic Peninsula margi ...
C2.3 Plate boundary earthquakes C2.3.1 Strike
... (3) Both plates continental crust. Continental crust is too buoyant (low density) for subduction and a mountain belt forms e.g. India-Asia collision in Himalaya and Tibet, Arabia-Eurasia collision in Eastern Anatolia ...
... (3) Both plates continental crust. Continental crust is too buoyant (low density) for subduction and a mountain belt forms e.g. India-Asia collision in Himalaya and Tibet, Arabia-Eurasia collision in Eastern Anatolia ...
GEOLOGIC STRUCTURE OF THE UPPERMOST OCEANIC CRUST
... volcanism on our planet as well as its most dramatic manifestation of extensional tectonics. Hydrothermal fluxes driven by magmatic heat through fractures in the crust change both the compositions of the rocks as well as the chemistry of the oceans. Seafloor spreading, probably initially at high rat ...
... volcanism on our planet as well as its most dramatic manifestation of extensional tectonics. Hydrothermal fluxes driven by magmatic heat through fractures in the crust change both the compositions of the rocks as well as the chemistry of the oceans. Seafloor spreading, probably initially at high rat ...
Seismic evidence for subduction-transported water in the lower mantle
... at the 660-km discontinuity [Antolik et al., 2004; Grand, 2002; Karason and van der Hilst, 2001; Masters et al., 2000; Megnin and Romanowicz, 2000; Ritsema and van Heijst, 2000]. Whether slabs penetrate to the core-mantle boundary or founder within the lower mantle, subduction clearly transports lar ...
... at the 660-km discontinuity [Antolik et al., 2004; Grand, 2002; Karason and van der Hilst, 2001; Masters et al., 2000; Megnin and Romanowicz, 2000; Ritsema and van Heijst, 2000]. Whether slabs penetrate to the core-mantle boundary or founder within the lower mantle, subduction clearly transports lar ...
Viscosity of the asthenosphere from glacial isostatic adjustment and
... [11] The viscosity of the mantle is averaged from the VM2 model [Peltier, 2004], except that the asthenospheric thickness and viscosity are allowed to vary (Figure 2). Asthenospheric thicknesses range from 140 to 380 km. Below the asthenosphere and above the 670-km discontinuity, the mantle viscosit ...
... [11] The viscosity of the mantle is averaged from the VM2 model [Peltier, 2004], except that the asthenospheric thickness and viscosity are allowed to vary (Figure 2). Asthenospheric thicknesses range from 140 to 380 km. Below the asthenosphere and above the 670-km discontinuity, the mantle viscosit ...
Evolutionary geochemical patterns of Late Cretaceous to
... scenarios generate melts with geochemical signatures diagnostic of Archean high-Al TTD/TTG (i.e. low Yb and Y concentrations, high Al, Na and Sr contents, and high La/Yb and Sr/Y ratios). Although most Phanerozoic dacite-granodiorite (island-arc type) suites are high in Yb and Y, with low Al, Na and ...
... scenarios generate melts with geochemical signatures diagnostic of Archean high-Al TTD/TTG (i.e. low Yb and Y concentrations, high Al, Na and Sr contents, and high La/Yb and Sr/Y ratios). Although most Phanerozoic dacite-granodiorite (island-arc type) suites are high in Yb and Y, with low Al, Na and ...
Geophysical Journal International
... were calculated using a Gibbs free-energy minimization algorithm (details in Connolly 2005). In this work, we used a modified version of the Holland & Powell (1998) thermodynamic database (Afonso & Zlotnik 2011). The resulting thermodynamic tables are generated by Perple-X (Connolly 2005), describin ...
... were calculated using a Gibbs free-energy minimization algorithm (details in Connolly 2005). In this work, we used a modified version of the Holland & Powell (1998) thermodynamic database (Afonso & Zlotnik 2011). The resulting thermodynamic tables are generated by Perple-X (Connolly 2005), describin ...
Tectonic evolution of the NW Sabah continental margin since the
... more closely spaced anticlines occur. This 'compressed fold belt' is probably separated from the delta toe by the eastward prolongation of the Kinarut-Mangalum fault. Further is the Lower Tertiary Thrust Sheet which is a huge allochthonous mass of imbricated sediments ('chaotic' seismic facies) reac ...
... more closely spaced anticlines occur. This 'compressed fold belt' is probably separated from the delta toe by the eastward prolongation of the Kinarut-Mangalum fault. Further is the Lower Tertiary Thrust Sheet which is a huge allochthonous mass of imbricated sediments ('chaotic' seismic facies) reac ...
Plate rotation during continental collision and its relationship with
... et al., 1998; Sperner et al., 2001]. Slab tearing has been shown to start where collision first occurred [Van Hunen and Allen, 2011]. The force balance for the continental collision and slab breakoff [Duretz et al., 2012] is influenced by the buoyancy of the partially subducted continental plate which ...
... et al., 1998; Sperner et al., 2001]. Slab tearing has been shown to start where collision first occurred [Van Hunen and Allen, 2011]. The force balance for the continental collision and slab breakoff [Duretz et al., 2012] is influenced by the buoyancy of the partially subducted continental plate which ...
IDOE Workshop on Tectonic Patterns and Metallogenesis in East
... eastern Asia,from the Sunda Arc to the Japanese islands,and from the stable shelfof the Gulf of Thailand to the stable shelf bordering northern Australia, provide one of the most significant regions of the earth's surface for the study of present-day tectonic processes and of their effects in the re ...
... eastern Asia,from the Sunda Arc to the Japanese islands,and from the stable shelfof the Gulf of Thailand to the stable shelf bordering northern Australia, provide one of the most significant regions of the earth's surface for the study of present-day tectonic processes and of their effects in the re ...
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.