The Basin and Range Province: Origin and Tectonic Significance
... by IDAHO STATE UNIVERSITY LIBRARY on 11/13/08. For personal use only. ...
... by IDAHO STATE UNIVERSITY LIBRARY on 11/13/08. For personal use only. ...
Thermal models of the Mexico subduction zone
... deposition history of incoming sediments, and the convergence rate. The thermal conductivity and radioactive heat generation of each rock unit must also be assigned. Two additional factors of potentially first-order importance are frictional heating along the thrust fault and hydrothermal circulatio ...
... deposition history of incoming sediments, and the convergence rate. The thermal conductivity and radioactive heat generation of each rock unit must also be assigned. Two additional factors of potentially first-order importance are frictional heating along the thrust fault and hydrothermal circulatio ...
Mechanisms for the Origin of Mid-Ocean Ridge Axial Topography: Implications
... Tm by 100øC then either vertical mantle flow or magma intrusion into the as suggestedfrom petrologic studies,this would increase the viscosity by approximatelytwo ordersof magnitude. While this effect has not been previously considered,it is potentially important and could result in the formation of ...
... Tm by 100øC then either vertical mantle flow or magma intrusion into the as suggestedfrom petrologic studies,this would increase the viscosity by approximatelytwo ordersof magnitude. While this effect has not been previously considered,it is potentially important and could result in the formation of ...
Imaging the mantle transition zone beneath eastern and central
... subuction of the Pacific and Philippine Sea Plates, and the collision of the Indian Plate on the east and southwest sides of China, respectively. The red rectangular region shows the location of the study area. Cyan lines indicate the descending Pacific, Philippine and Indian Plates. Gray dash lines r ...
... subuction of the Pacific and Philippine Sea Plates, and the collision of the Indian Plate on the east and southwest sides of China, respectively. The red rectangular region shows the location of the study area. Cyan lines indicate the descending Pacific, Philippine and Indian Plates. Gray dash lines r ...
Thermal Structure due to Solid-State Flow in the Mantle
... with petrologic constraints. One caveat is that trajectories of melt migration beneath an arc might not be vertical. Porous flow might lead to melt migration vectors that ascend diagonally toward the wedge corner either due to pressure gradients in the mantle flow [Spiegelman and McKenzie, 1987; Phi ...
... with petrologic constraints. One caveat is that trajectories of melt migration beneath an arc might not be vertical. Porous flow might lead to melt migration vectors that ascend diagonally toward the wedge corner either due to pressure gradients in the mantle flow [Spiegelman and McKenzie, 1987; Phi ...
- Wiley Online Library
... The present Cascadia subduction system and volcanic arc was established 40 Ma with disappearance of the Farallon plate and development of the Juan de Fuca plate [Humphreys, 2008]. In middle Cenozoic time, the arc extended farther south to present day southwestern Nevada but has shortened northward ...
... The present Cascadia subduction system and volcanic arc was established 40 Ma with disappearance of the Farallon plate and development of the Juan de Fuca plate [Humphreys, 2008]. In middle Cenozoic time, the arc extended farther south to present day southwestern Nevada but has shortened northward ...
2014-Wannamaker-Casc.. - University of Alberta
... The present Cascadia subduction system and volcanic arc was established 40 Ma with disappearance of the Farallon plate and development of the Juan de Fuca plate [Humphreys, 2008]. In middle Cenozoic time, the arc extended farther south to present day southwestern Nevada but has shortened northward ...
... The present Cascadia subduction system and volcanic arc was established 40 Ma with disappearance of the Farallon plate and development of the Juan de Fuca plate [Humphreys, 2008]. In middle Cenozoic time, the arc extended farther south to present day southwestern Nevada but has shortened northward ...
Crustal motion in the Southern Andes (26°–36°S): Do the Andes
... [2] Surface velocity fields measured with GPS (Global Positioning System) geodesy promise new insight into the incremental processes that actively deform continents and, over geologic time, construct mountains. For continental regions associated with plate boundaries such as the Andes of South Ameri ...
... [2] Surface velocity fields measured with GPS (Global Positioning System) geodesy promise new insight into the incremental processes that actively deform continents and, over geologic time, construct mountains. For continental regions associated with plate boundaries such as the Andes of South Ameri ...
Three Dimensional Electrical Structure of the Crust and Upper
... mid-to-lower crust beneath the northern part of Ordos. Correlating well with results of ...
... mid-to-lower crust beneath the northern part of Ordos. Correlating well with results of ...
Conductivity distribution and seismicity in the northeastern Japan Arc Yukio Fujinawa
... zones. In Tables 1 and 2, we have semi-quantitatively summarized the features of geological and geophysical data at these zones in the upper crust, and in the lower crust, respectively, for the sake of convenience. The Asahi Mountain Range, with many of active faults, is contrasted from the central ...
... zones. In Tables 1 and 2, we have semi-quantitatively summarized the features of geological and geophysical data at these zones in the upper crust, and in the lower crust, respectively, for the sake of convenience. The Asahi Mountain Range, with many of active faults, is contrasted from the central ...
Thermal modeling of continental subduction and exhumation
... Received 17 December 1998; accepted for publication 12 May 2000 ...
... Received 17 December 1998; accepted for publication 12 May 2000 ...
The Neoarchean Ophiolite in the North China Craton: Early
... unit, then into a unit of metamorphosed mafic amphibolites that locally include remnants of pillow lavas and dike complexes. One of the most contentious issues has been the age of the relatively small central belt of the Dongwanzi ophiolite. Kusky et al. (2001) interpreted this belt to be part of th ...
... unit, then into a unit of metamorphosed mafic amphibolites that locally include remnants of pillow lavas and dike complexes. One of the most contentious issues has been the age of the relatively small central belt of the Dongwanzi ophiolite. Kusky et al. (2001) interpreted this belt to be part of th ...
Inconsistent correlation of seismic layer 2a and lava layer thickness
... in thickness, but thicknesses are greater at the BTF than at the HDR (Fig. 2). The average thicknesses of the lava units exposed at the HDR and the BTF are 300 m and 450 m, respectively; the average thicknesses of the transition zone are 150 m and 700 m, respectively. The mean thickness of the lava ...
... in thickness, but thicknesses are greater at the BTF than at the HDR (Fig. 2). The average thicknesses of the lava units exposed at the HDR and the BTF are 300 m and 450 m, respectively; the average thicknesses of the transition zone are 150 m and 700 m, respectively. The mean thickness of the lava ...
Geophysical and Geochemical Constraints at Converging Plate
... walls of the median valley and transverse fracture zones and sometimes even on the tops of crestal mountains of the Mid-Atlantic and Mid-Indian Ocean Ridges (see below). A similar rock suite has been recovered from the south-eastern Pacific (Nishimori & Anderson 1973). It appears that, except for a ...
... walls of the median valley and transverse fracture zones and sometimes even on the tops of crestal mountains of the Mid-Atlantic and Mid-Indian Ocean Ridges (see below). A similar rock suite has been recovered from the south-eastern Pacific (Nishimori & Anderson 1973). It appears that, except for a ...
- ResearchOnline@JCU
... characteristics of enriched and normal mid-ocean ridge basalt, back-arc basin basalt, alkaline basalt, plagioclase-rich cumulate, seafloor-altered basalt and Fe – Ti basalt. All of the samples studied represent a single slice of oceanic crust interpreted to have formed in a back-arc or marginal basi ...
... characteristics of enriched and normal mid-ocean ridge basalt, back-arc basin basalt, alkaline basalt, plagioclase-rich cumulate, seafloor-altered basalt and Fe – Ti basalt. All of the samples studied represent a single slice of oceanic crust interpreted to have formed in a back-arc or marginal basi ...
Foundering of lower island-arc crust as an explanation for the origin
... with a corresponding VP of 6.5–7.5 km s21 (Fig. 1a, b)17. This low VP/VS indicates that quartz-bearing lithologies are present in the arc lower crust and the quartz must be mostly the low-temperature alpha-quartz pseudomorph (Fig. 1a, b). These observations constrain the spatially averaged temperatu ...
... with a corresponding VP of 6.5–7.5 km s21 (Fig. 1a, b)17. This low VP/VS indicates that quartz-bearing lithologies are present in the arc lower crust and the quartz must be mostly the low-temperature alpha-quartz pseudomorph (Fig. 1a, b). These observations constrain the spatially averaged temperatu ...
A Review of the Role of Subduction Dynamics for Regional and
... However, any such geologic and geodetic data can only constrain relative motions, and further assumptions are required to define an absolute reference frame. For HS-3, it is of the hotspot kind, and was inferred from ten Pacific ocean island age progressions (Gripp and Gordon, 2002). The idea behind ...
... However, any such geologic and geodetic data can only constrain relative motions, and further assumptions are required to define an absolute reference frame. For HS-3, it is of the hotspot kind, and was inferred from ten Pacific ocean island age progressions (Gripp and Gordon, 2002). The idea behind ...
14. Some Aspects of Plate Tectonics in the Arabian Sea
... 1971). Although part of such fracture zones may now be covered by the Maldive Islands, it appears quite possible ...
... 1971). Although part of such fracture zones may now be covered by the Maldive Islands, it appears quite possible ...
Canada`s craton: A bottoms-up view
... the ubiquity (or not) of Si enrichment (low Mg/Si). The ΔMg/Si for cratonic mantle as a whole is normally distributed about zero, similar to other kinds of mantle lithosphere (Fig. 7). Thus, “Si enrichment” in cratonic mantle is an exception, occurring in a minority of samples. Indeed, the lower Mg/ ...
... the ubiquity (or not) of Si enrichment (low Mg/Si). The ΔMg/Si for cratonic mantle as a whole is normally distributed about zero, similar to other kinds of mantle lithosphere (Fig. 7). Thus, “Si enrichment” in cratonic mantle is an exception, occurring in a minority of samples. Indeed, the lower Mg/ ...
Thickness of the lithosphere beneath Turkey and
... et al., 2013; Vinnik et al., 2014). Interpretations from these studies are either confined to a limited region or to a limited depth extent, i.e., to crustal depths only. Thus, the variations of lithospheric thickness have not yet been homogeneously characterized in Turkey and surroundings. A robust ...
... et al., 2013; Vinnik et al., 2014). Interpretations from these studies are either confined to a limited region or to a limited depth extent, i.e., to crustal depths only. Thus, the variations of lithospheric thickness have not yet been homogeneously characterized in Turkey and surroundings. A robust ...
Active tectonic deformation at the transition from the
... Bohemian Massif represents the European platform in the north. In the south, Istria represents the part of the Adriatic plate, which was scarcely affected by the Alpine orogenesis. The Molasse basin in the north and the Venetien and Po plain in the south are typical forland basins, generated by the ...
... Bohemian Massif represents the European platform in the north. In the south, Istria represents the part of the Adriatic plate, which was scarcely affected by the Alpine orogenesis. The Molasse basin in the north and the Venetien and Po plain in the south are typical forland basins, generated by the ...
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.