seismic potential associated with subduction in the northwestern
... We have seen that there are systematic differences between subduction zones that are capable of great earthquakes and those that are not. The Juan de Fuca subduction zone has been ignored in the studies that established these differences. The Juan de Fuca subduction zone has been considered somewhat ...
... We have seen that there are systematic differences between subduction zones that are capable of great earthquakes and those that are not. The Juan de Fuca subduction zone has been ignored in the studies that established these differences. The Juan de Fuca subduction zone has been considered somewhat ...
Constraining P-wave velocity variations in the upper mantle beneath
... collision (Molnar and Tapponnier, 1975). However, both the collision and the subduction processes, along with their impact on mantle (return) flow beneath the region, must be taken into account in order to obtain a complete understanding of the dynamics and the tectonic evolution of SE Asia. It can ...
... collision (Molnar and Tapponnier, 1975). However, both the collision and the subduction processes, along with their impact on mantle (return) flow beneath the region, must be taken into account in order to obtain a complete understanding of the dynamics and the tectonic evolution of SE Asia. It can ...
Strength of the lithosphere and strain localisation in the Baikal rift
... which are not reproduced by the conductive model. These local highs are likely to correspond to hydrothermal circulation along major faults (Poort and Klerkx, 2004), rather than to conductive heat transfer. In the southwestern part of the rift, the observed local high of ~150 mW/m2 corresponds to th ...
... which are not reproduced by the conductive model. These local highs are likely to correspond to hydrothermal circulation along major faults (Poort and Klerkx, 2004), rather than to conductive heat transfer. In the southwestern part of the rift, the observed local high of ~150 mW/m2 corresponds to th ...
Ultraslow, slow, or fast spreading ridges
... and therefore the mantle temperatures that would derive from these estimates – is meaningless. Regardless, it follows from the apparent relationship between spreading rates and sublithospheric mantle temperatures that the mantle should be even colder underneath ultraslow spreading ridges. The slower ...
... and therefore the mantle temperatures that would derive from these estimates – is meaningless. Regardless, it follows from the apparent relationship between spreading rates and sublithospheric mantle temperatures that the mantle should be even colder underneath ultraslow spreading ridges. The slower ...
Introduction: Anatomy of rifting: Tectonics and magmatism in
... volcanism. Studies of a wide variety of extensional processes ranging from plate thinning to magma intrusion have helped scientists understand how continents are broken apart to form ocean basins. However, deformation processes vary significantly during the development of continental rifts and midoc ...
... volcanism. Studies of a wide variety of extensional processes ranging from plate thinning to magma intrusion have helped scientists understand how continents are broken apart to form ocean basins. However, deformation processes vary significantly during the development of continental rifts and midoc ...
Lateral Density Inhomogeneities of the Continental and Oceanic
... a shallower (4–5.5 km) level of the FMS depth; the parallel zone located south of the previous one has a deeper (up to 6 km) FMS level and presumably corre sponds to the boundary thrust zone between Asia and the Indian Plate [23]. The Tibetan Plateau is mainly characterized by the FMS depths from 4 ...
... a shallower (4–5.5 km) level of the FMS depth; the parallel zone located south of the previous one has a deeper (up to 6 km) FMS level and presumably corre sponds to the boundary thrust zone between Asia and the Indian Plate [23]. The Tibetan Plateau is mainly characterized by the FMS depths from 4 ...
Continental Drift
... Rock Clues If the continents were connected at one time, then rocks that make up the continents should be the same in locations where they were joined. Similar rock structures are found on different continents. Parts of the Appalachian Mountains of the eastern United States are similar to those foun ...
... Rock Clues If the continents were connected at one time, then rocks that make up the continents should be the same in locations where they were joined. Similar rock structures are found on different continents. Parts of the Appalachian Mountains of the eastern United States are similar to those foun ...
Crustal and uppermantle structure in the Eastern Mediterranean
... crust. Although a unique explanation is not yet given, it is globally accepted that the combination of the subduction system to the west and the convergence of the plates to the east produces the westward motion of the Anatolian microplate, which is bounded by strikeslip faults, the dextral Nort ...
... crust. Although a unique explanation is not yet given, it is globally accepted that the combination of the subduction system to the west and the convergence of the plates to the east produces the westward motion of the Anatolian microplate, which is bounded by strikeslip faults, the dextral Nort ...
Panza-Pontevivo p. 38 - Accademia Nazionale delle Scienze detta
... The Calabrian Arc is involved in the subduction of the Ionian lithosphere towards north-west, below the Tyrrhenian Sea, where the depth of the earthquake sources increases with increasing distance from the Calabrian Arc [4, 19, 21]. This Wadati-Benioff Zone represents an interesting object of study. ...
... The Calabrian Arc is involved in the subduction of the Ionian lithosphere towards north-west, below the Tyrrhenian Sea, where the depth of the earthquake sources increases with increasing distance from the Calabrian Arc [4, 19, 21]. This Wadati-Benioff Zone represents an interesting object of study. ...
Driving mechanism and 3-D circulation of plate tectonics
... crust (Fig. 2)— the broadest features of plate tectonics. The Atlantic spreads slowly and has no subduction about its margins, except for the small Caribbean and Scotia arcs, and the subduction-free Arctic Ocean spreads slower yet. The Pacific spreads rapidly, is mostly rimmed by subduction systems ...
... crust (Fig. 2)— the broadest features of plate tectonics. The Atlantic spreads slowly and has no subduction about its margins, except for the small Caribbean and Scotia arcs, and the subduction-free Arctic Ocean spreads slower yet. The Pacific spreads rapidly, is mostly rimmed by subduction systems ...
Numerical models of slab migration in continental collision zones
... lithosphere is determined by a half-space cooling model for a 50-Myr-old plate (Turcotte and Schubert, 2002). For the continental lithosphere, temperature extends linearly from 0 ◦ C at the surface to the mantle reference temperature at 150 km depth. A 40-km-deep continental crust is characterized b ...
... lithosphere is determined by a half-space cooling model for a 50-Myr-old plate (Turcotte and Schubert, 2002). For the continental lithosphere, temperature extends linearly from 0 ◦ C at the surface to the mantle reference temperature at 150 km depth. A 40-km-deep continental crust is characterized b ...
Developing the plate tectonics from oceanic subduction to
... Drilling (CCSD) project has been accomplished between 2001―2005 at Donghai in the Sulu UHP terrane, providing an advantageous and rare chance for collecting UHP rock samples continuously from its main hole (MH) as deep as 5158 m. A great deal of studies have demonstrated that continental and oceanic ...
... Drilling (CCSD) project has been accomplished between 2001―2005 at Donghai in the Sulu UHP terrane, providing an advantageous and rare chance for collecting UHP rock samples continuously from its main hole (MH) as deep as 5158 m. A great deal of studies have demonstrated that continental and oceanic ...
The World in Wax - Bodenschatz group
... the Earth’s belly. Snapping and cracking, the viscous liquid hardens into volcanic rock in the cold water. There is a constant rumbling and groaning in the darkness below the sea where the Earth’s surface cracks. These seething cracks, which extend like gigantic scars thousands of kilometers around ...
... the Earth’s belly. Snapping and cracking, the viscous liquid hardens into volcanic rock in the cold water. There is a constant rumbling and groaning in the darkness below the sea where the Earth’s surface cracks. These seething cracks, which extend like gigantic scars thousands of kilometers around ...
The African Plate: A history of oceanic crust accretion and
... crust, representing a period of more than 2.5 billion years of continental and oceanic crust growth (e.g. Burke, 1996). Initially part of Gondwana since 550 million years (Ma) and Pangea since 320 Ma, and now surrounded almost entirely by spreading centers, the African plate moved relatively slowly ...
... crust, representing a period of more than 2.5 billion years of continental and oceanic crust growth (e.g. Burke, 1996). Initially part of Gondwana since 550 million years (Ma) and Pangea since 320 Ma, and now surrounded almost entirely by spreading centers, the African plate moved relatively slowly ...
1. Introduction, Objectives, and Principal Results, Leg 112, Peru
... sided. Objectives at Site 683, at the distal edge of the Yaquina Basin, included verification that continental crust extends this far seaward with considerable subsidence. We included this objective with those of a site across the tectonic boundary separating the two types of crust. The objectives a ...
... sided. Objectives at Site 683, at the distal edge of the Yaquina Basin, included verification that continental crust extends this far seaward with considerable subsidence. We included this objective with those of a site across the tectonic boundary separating the two types of crust. The objectives a ...
Major and Trace Element Composition of the Depleted MORB
... ln([A]) vs. ln([B]) relationships to consider in the overall reduction of this dataset; Figure 2 shows a sampling of these linear arrays, with the more incompatible of a given element pair plotted on the x-axis. The peridotites show an extremely wide range in degree of depletion and form well-correl ...
... ln([A]) vs. ln([B]) relationships to consider in the overall reduction of this dataset; Figure 2 shows a sampling of these linear arrays, with the more incompatible of a given element pair plotted on the x-axis. The peridotites show an extremely wide range in degree of depletion and form well-correl ...
proposta comercial
... After defining the location of the seep area IMX062 on the seafloor, we integrated this information with available geological and geophysical data in order to increase the confidence about oil natural leaking in that region. According to CHN (2015), the Perdido Fold Belt Province is constituted by a ...
... After defining the location of the seep area IMX062 on the seafloor, we integrated this information with available geological and geophysical data in order to increase the confidence about oil natural leaking in that region. According to CHN (2015), the Perdido Fold Belt Province is constituted by a ...
imp prefaz.qxp - Istituto Nazionale di Oceanografia e di Geofisica
... In Fig. 2, the synthesis proposed by Cassinis et al. (2003) shows the crustal domains, the Moho depth contours as well as the main tectonic features in the deep crust as interpreted from the DSS data (see the figure captions). Besides the three major domains (European, AdriaticAfrican and sub oceani ...
... In Fig. 2, the synthesis proposed by Cassinis et al. (2003) shows the crustal domains, the Moho depth contours as well as the main tectonic features in the deep crust as interpreted from the DSS data (see the figure captions). Besides the three major domains (European, AdriaticAfrican and sub oceani ...
Rhenium–osmium isotope and elemental behaviour during
... the original sample composition fell either within the MORB field (for basalts) or within the field defined by the measured unaltered gabbros (for gabbroic lithologies). Thus, it can be estimated that the circled sample (Fig. 3a) may have lost approximately 80% of its initial Ba. Both Rb and K (not ...
... the original sample composition fell either within the MORB field (for basalts) or within the field defined by the measured unaltered gabbros (for gabbroic lithologies). Thus, it can be estimated that the circled sample (Fig. 3a) may have lost approximately 80% of its initial Ba. Both Rb and K (not ...
Plate tectonic controls on atmospheric CO2 levels since the Triassic
... rate scenario (32), however, requires a constant average subduction rate of 6 ± 1 cm/y (Fig. 2B), i.e., similar to the present day (24). We adopt here a more or less constant global average of subduction rates as we see no geodynamic cause why the process of subduction and the mechanical interaction ...
... rate scenario (32), however, requires a constant average subduction rate of 6 ± 1 cm/y (Fig. 2B), i.e., similar to the present day (24). We adopt here a more or less constant global average of subduction rates as we see no geodynamic cause why the process of subduction and the mechanical interaction ...
Models of Mantle Convection Incorporating Plate Tectonics: The
... Mantle convection is the means by which heat is removed from the deep interior of the planet. Plate tectonics defines the dominant mode of mantle convection and subduction is responsible for creating most density heterogeneity within the mantle as imaged by seismic tomography. The oceanic lithospher ...
... Mantle convection is the means by which heat is removed from the deep interior of the planet. Plate tectonics defines the dominant mode of mantle convection and subduction is responsible for creating most density heterogeneity within the mantle as imaged by seismic tomography. The oceanic lithospher ...
Empirical relationship for marine primary production : the
... temporal and spatial extent of production estimates. For predictive purposes, primary production integrated over the euphotic zone has been related empirically to surface chlorophyll and chlorophyll integrated through the water column (Lorenzen, 1970; Smith, Baker, 1978; ...
... temporal and spatial extent of production estimates. For predictive purposes, primary production integrated over the euphotic zone has been related empirically to surface chlorophyll and chlorophyll integrated through the water column (Lorenzen, 1970; Smith, Baker, 1978; ...
Mechanism and timing of Pb transport from subducted oceanic crust
... derived from the continental crust, represent recycling of continental material, some of which is returned to the deeper mantle. Element transfer at subduction zones is therefore an important process in the chemical differentiation of the Earth, and many previous studies have sought to determine the ...
... derived from the continental crust, represent recycling of continental material, some of which is returned to the deeper mantle. Element transfer at subduction zones is therefore an important process in the chemical differentiation of the Earth, and many previous studies have sought to determine the ...
Variations in magmatic processes along the East Greenland
... Seismic velocities and the associated thicknesses of rifted and igneous crust provide key constraints on the rifting history, the differentiation between non-volcanic and volcanic rifted margins, the driving force of magmatism at volcanic margins, that is, active or passive upwelling and the tempera ...
... Seismic velocities and the associated thicknesses of rifted and igneous crust provide key constraints on the rifting history, the differentiation between non-volcanic and volcanic rifted margins, the driving force of magmatism at volcanic margins, that is, active or passive upwelling and the tempera ...
Serpentinites - Elements Magazine
... Serpentinites—water-rich rocks composed mostly of these modern serpentinites has provided useful inforserpentine-group minerals (chrysotile, lizardite and antigmation for identifying the protoliths of serpentinites in orite)—are present in almost all continents and island arcs. They form large massi ...
... Serpentinites—water-rich rocks composed mostly of these modern serpentinites has provided useful inforserpentine-group minerals (chrysotile, lizardite and antigmation for identifying the protoliths of serpentinites in orite)—are present in almost all continents and island arcs. They form large massi ...
Abyssal plain
An abyssal plain is an underwater plain on the deep ocean floor, usually found at depths between 3000 and 6000 m. Lying generally between the foot of a continental rise and a mid-ocean ridge, abyssal plains cover more than 50% of the Earth’s surface. They are among the flattest, smoothest and least explored regions on Earth. Abyssal plains are key geologic elements of oceanic basins (the other elements being an elevated mid-ocean ridge and flanking abyssal hills). In addition to these elements, active oceanic basins (those that are associated with a moving plate tectonic boundary) also typically include an oceanic trench and a subduction zone.Abyssal plains were not recognized as distinct physiographic features of the sea floor until the late 1940s and, until very recently, none had been studied on a systematic basis. They are poorly preserved in the sedimentary record, because they tend to be consumed by the subduction process. The creation of the abyssal plain is the end result of spreading of the seafloor (plate tectonics) and melting of the lower oceanic crust. Magma rises from above the asthenosphere (a layer of the upper mantle) and as this basaltic material reaches the surface at mid-ocean ridges it forms new oceanic crust. This is constantly pulled sideways by spreading of the seafloor. Abyssal plains result from the blanketing of an originally uneven surface of oceanic crust by fine-grained sediments, mainly clay and silt. Much of this sediment is deposited by turbidity currents that have been channelled from the continental margins along submarine canyons down into deeper water. The remainder of the sediment is composed chiefly of pelagic sediments. Metallic nodules are common in some areas of the plains, with varying concentrations of metals, including manganese, iron, nickel, cobalt, and copper. These nodules may provide a significant resource for future mining ventures.Owing in part to their vast size, abyssal plains are currently believed to be a major reservoir of biodiversity. The abyss also exerts significant influence upon ocean carbon cycling, dissolution of calcium carbonate, and atmospheric CO2 concentrations over timescales of 100–1000 years. The structure and function of abyssal ecosystems are strongly influenced by the rate of flux of food to the seafloor and the composition of the material that settles. Factors such as climate change, fishing practices, and ocean fertilization are expected to have a substantial effect on patterns of primary production in the euphotic zone. This will undoubtedly impact the flux of organic material to the abyss in a similar manner and thus have a profound effect on the structure, function and diversity of abyssal ecosystems.