Uppermost mantle structure of the eastern margin of the Tibetan
... 2000) and traveltime tomography (Zhang and Thurber, 2003). For Pn arrivals, when an earthquake lies approximately on the extension of the great circle path connecting two stations, the portion of Pn wave travel times along the overlapped ray paths are almost identical (Fig. 2) (Phillips et al., 2005 ...
... 2000) and traveltime tomography (Zhang and Thurber, 2003). For Pn arrivals, when an earthquake lies approximately on the extension of the great circle path connecting two stations, the portion of Pn wave travel times along the overlapped ray paths are almost identical (Fig. 2) (Phillips et al., 2005 ...
Geological history of the Baja California Peninsula
... California (Figures 14, 15, 16). They were formed as a result of volcanism associated with the passing of the East Pacific Rise under the continent and beginning of opening of the Gulf of California. It is well known that Earth’s crust is composed of several large and small semi-rigid plates that “f ...
... California (Figures 14, 15, 16). They were formed as a result of volcanism associated with the passing of the East Pacific Rise under the continent and beginning of opening of the Gulf of California. It is well known that Earth’s crust is composed of several large and small semi-rigid plates that “f ...
An____________is a movement of Earth’s lithosphere shift, releasing stored energy.
... Within Earth’s crust, forces cause the two sides of a fault to move past each other. Sometimes the rocks along the sides of a fault may snag and remain locked because of ______________. Tremendous stress builds up in these areas. When rocks are strained beyond their limit, they break and grind past ...
... Within Earth’s crust, forces cause the two sides of a fault to move past each other. Sometimes the rocks along the sides of a fault may snag and remain locked because of ______________. Tremendous stress builds up in these areas. When rocks are strained beyond their limit, they break and grind past ...
Ancient recycled mantle lithosphere in the Hawaiian plume: Osmium
... Generation of basaltic oceanic crust at divergent plate boundaries (i.e. mid oceanic ridges) and recycling of the lithospheric plate back into the Earth's mantle via subduction at convergent plate boundaries play a principle role in the generation of long-lived chemical and isotopic heterogeneities ...
... Generation of basaltic oceanic crust at divergent plate boundaries (i.e. mid oceanic ridges) and recycling of the lithospheric plate back into the Earth's mantle via subduction at convergent plate boundaries play a principle role in the generation of long-lived chemical and isotopic heterogeneities ...
Exhumation processes - Perso-sdt
... and follow with a summary of relevant tectonic parameters. Then, we review the characteristics of exhumation in different tectonic settings. For instance, continental rifts, such as the severely extended Basin-and-Range province, appear to exhume only middle and upper crustal rocks, whereas continen ...
... and follow with a summary of relevant tectonic parameters. Then, we review the characteristics of exhumation in different tectonic settings. For instance, continental rifts, such as the severely extended Basin-and-Range province, appear to exhume only middle and upper crustal rocks, whereas continen ...
OBSERVATIONAL AND THEORETICAL STUDIES OF THE DYNAMICS OF MANTLE PLUME–MID-OCEAN RIDGE INTERACTION
... [12] Geophysical studies at the Iceland and Galapagos hot spot–ridge systems show compelling evidence for ridge interactions with hot mantle plumes. Iceland is a classic example of a ridge-centered plume. Here the Mid-Atlantic Ridge rises ⬃4 km above normal ridge depths (Figure 2a) reaching an eleva ...
... [12] Geophysical studies at the Iceland and Galapagos hot spot–ridge systems show compelling evidence for ridge interactions with hot mantle plumes. Iceland is a classic example of a ridge-centered plume. Here the Mid-Atlantic Ridge rises ⬃4 km above normal ridge depths (Figure 2a) reaching an eleva ...
Document
... 1994; Agard et al. 2005). The Zagros Orogen extends from eastern Turkey through northern Iraq and northwest of Iran to the Hormuz Strait and Oman (Alavi 1994; McQuarrie 2004; Agard et al. 2005; Homke et al. 2010). Because of the key situation of the Zagros Orogen within the Alpine–Himalayan Orogenic ...
... 1994; Agard et al. 2005). The Zagros Orogen extends from eastern Turkey through northern Iraq and northwest of Iran to the Hormuz Strait and Oman (Alavi 1994; McQuarrie 2004; Agard et al. 2005; Homke et al. 2010). Because of the key situation of the Zagros Orogen within the Alpine–Himalayan Orogenic ...
Oceanic microplate formation records the onset of India
... is shaded green. BR, Broken Ridge. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) ...
... is shaded green. BR, Broken Ridge. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) ...
Trace element and isotope geochemistry of gabbro
... granulites were emplaced at about 290 Ma at deep crustal levels, where they underwent slow cooling and recrystallization under granulite-facies conditions (P = 0.7-0.8 GPa, T = 800-900~ They were exhumed to upper levels, in association with the felsic granulites, in late Triassic-middle Jurassic tim ...
... granulites were emplaced at about 290 Ma at deep crustal levels, where they underwent slow cooling and recrystallization under granulite-facies conditions (P = 0.7-0.8 GPa, T = 800-900~ They were exhumed to upper levels, in association with the felsic granulites, in late Triassic-middle Jurassic tim ...
Paper 3.2 Mb pdf - Miles F Osmaston
... 1984; Smith, 1984), the attention of the author was attracted to the apparently severe décollement problem, from an engineering perspective, presented by the presence in the Eastern Alps of crystalline basement thrust sheets of large cross-strike extent and limited thickness (large aspect ratio). Th ...
... 1984; Smith, 1984), the attention of the author was attracted to the apparently severe décollement problem, from an engineering perspective, presented by the presence in the Eastern Alps of crystalline basement thrust sheets of large cross-strike extent and limited thickness (large aspect ratio). Th ...
On origin of near-axis volcanism and faulting at fast spreading mid
... formation of the abyssal hills. It has been suggested that outward-dipping faults can form at fast spreading ridges because of a less dramatic thickening of the brittle layer away from the ridge axis compared to slow spreading ridges [20,21]. However, it is unclear whether the reduced variability in ...
... formation of the abyssal hills. It has been suggested that outward-dipping faults can form at fast spreading ridges because of a less dramatic thickening of the brittle layer away from the ridge axis compared to slow spreading ridges [20,21]. However, it is unclear whether the reduced variability in ...
Crustal warpinga possible tectonic control of alkaline magmatism
... due to the lifting of part of the load on the layers under the sxvells,and eruption was facilitated by the fractures.'This is an essentialpart of the process elaborated in this paper. ...
... due to the lifting of part of the load on the layers under the sxvells,and eruption was facilitated by the fractures.'This is an essentialpart of the process elaborated in this paper. ...
Modification of the Continental Crust by Subduction Zone
... Rocks from all three centers are porphyritic with 30% to 60% by volume phenocrysts (average ~40%). Plagioclase is the most abundant phenocryst phase in all samples, accounting for 50% to 75% of the mineral assemblage in many of the samples. Other phenocryst phases are present in variable amounts and ...
... Rocks from all three centers are porphyritic with 30% to 60% by volume phenocrysts (average ~40%). Plagioclase is the most abundant phenocryst phase in all samples, accounting for 50% to 75% of the mineral assemblage in many of the samples. Other phenocryst phases are present in variable amounts and ...
Fluid flow through seamounts and implications for global mass fluxes
... and conductive heat flow at the seafloor is only slightly reduced across the seamount due to bathymetric refraction. However, fluid recharge over a broad region on the flank of the seamount (Fig. 2B) depresses isotherms, and discharge focused across the top of the edifice raises isotherms. The resul ...
... and conductive heat flow at the seafloor is only slightly reduced across the seamount due to bathymetric refraction. However, fluid recharge over a broad region on the flank of the seamount (Fig. 2B) depresses isotherms, and discharge focused across the top of the edifice raises isotherms. The resul ...
Southeast Asia`s changing palaeogeography
... and volcanic islands separated by small ocean basins: the Malay Archipelago of Alfred Russel Wallace (1869). There are thousands of islands spread across the equator in the area over 5 000 km wide between 95 °E and 140 °E (Fig. 1). To the south, west and east the region is surrounded by volcanic arc ...
... and volcanic islands separated by small ocean basins: the Malay Archipelago of Alfred Russel Wallace (1869). There are thousands of islands spread across the equator in the area over 5 000 km wide between 95 °E and 140 °E (Fig. 1). To the south, west and east the region is surrounded by volcanic arc ...
Crustal and upper mantle structure of northern Tibet imaged with
... thinnest in the Songpan-Ganze terrane. The PASSCAL survey also showed that shear waves do not propagate efficiently in the upper mantle in northern Tibet, implying high temperatures and possibly partial melting. The zone of shear wave attenuation in the upper mantle is spatially coincident with the ...
... thinnest in the Songpan-Ganze terrane. The PASSCAL survey also showed that shear waves do not propagate efficiently in the upper mantle in northern Tibet, implying high temperatures and possibly partial melting. The zone of shear wave attenuation in the upper mantle is spatially coincident with the ...
The Architecture, Chemistry, and Evolution of - Cin
... 2.4.1. Extinct arcs. The western North American Cordillera comprises a continuous belt of arc products (mostly intrusive) from Alaska to Baja California (Figure 3a). These are the great North American batholiths, with ages ranging from Triassic to Eocene (Table 1) (Anderson 1990). All these batholit ...
... 2.4.1. Extinct arcs. The western North American Cordillera comprises a continuous belt of arc products (mostly intrusive) from Alaska to Baja California (Figure 3a). These are the great North American batholiths, with ages ranging from Triassic to Eocene (Table 1) (Anderson 1990). All these batholit ...
Papers presented to the Conference on Heat and Detachment in
... relatively thick, strong high viscosity zone (about 30 km thick [5]), again too thick for expected crustal temperatures. How can these large rift structures which appear to require a thick, strong lithosphere be reconciled with the hot, apparently thin lithosphere implied by rock rheology at venusia ...
... relatively thick, strong high viscosity zone (about 30 km thick [5]), again too thick for expected crustal temperatures. How can these large rift structures which appear to require a thick, strong lithosphere be reconciled with the hot, apparently thin lithosphere implied by rock rheology at venusia ...
Geophysical and petrological modelling of the
... Information on the physical and chemical properties of the lithosphere–asthenosphere system (LAS) can be obtained by geophysical investigation and by studies of petrology–geochemistry of magmatic rocks and entrained xenoliths. Integration of petrological and geophysical studies is particularly usefu ...
... Information on the physical and chemical properties of the lithosphere–asthenosphere system (LAS) can be obtained by geophysical investigation and by studies of petrology–geochemistry of magmatic rocks and entrained xenoliths. Integration of petrological and geophysical studies is particularly usefu ...
55. The Western Rockall Plateau
... trends northeast-southwest parallel to the northwest margin of the plateau. At 57°N, the main part of the basin consists of a 60-km-wide graben underlain by an irregular relief of about 0.5 s that may be indicative of block faulting. At 57°N, there is a major change in the trend, structure and depth ...
... trends northeast-southwest parallel to the northwest margin of the plateau. At 57°N, the main part of the basin consists of a 60-km-wide graben underlain by an irregular relief of about 0.5 s that may be indicative of block faulting. At 57°N, there is a major change in the trend, structure and depth ...
Structure of the crust beneath the southeastern Tibetan Plateau from
... support of the crust-mantle decoupling and middle/lower crustal flow, but to date the observations have been too sparse to determine whether this crustal low-velocity zone extends into the southeastern part of the Tibetan Plateau. Moreover, as we will show here, it is likely that neither end-member ...
... support of the crust-mantle decoupling and middle/lower crustal flow, but to date the observations have been too sparse to determine whether this crustal low-velocity zone extends into the southeastern part of the Tibetan Plateau. Moreover, as we will show here, it is likely that neither end-member ...
Variations in amount and direction of seafloor spreading along
... JMFZ. They suggested that this differential spreading was responsible for compressional inversion of the Vøring and Faeroe-Shetland Basins, rather than the Møre Basin. [6] So as to investigate this idea more fully, we have developed a method for palinspastic reconstruction of oceanic domains. Instea ...
... JMFZ. They suggested that this differential spreading was responsible for compressional inversion of the Vøring and Faeroe-Shetland Basins, rather than the Møre Basin. [6] So as to investigate this idea more fully, we have developed a method for palinspastic reconstruction of oceanic domains. Instea ...
CRUSTAL STRUCTURE OF THE TIBETAN PLATEAU AND ITS
... The Tibetan Plateau is the highest and largest plateau in the world, generated by the collision of India and Eurasia. Details of this continent-continent collision and the uplift mechanism of the plateau are still hotly debated. In this study, I collected a large amount of seismic waveform data reco ...
... The Tibetan Plateau is the highest and largest plateau in the world, generated by the collision of India and Eurasia. Details of this continent-continent collision and the uplift mechanism of the plateau are still hotly debated. In this study, I collected a large amount of seismic waveform data reco ...
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.