Omarini, Ricardo H., Massimo Gasparon, Angelo
... mechanism is the Alto Paraguay Triassic alkaline magmatism at the border of the Rio Apa block. This area was affected by rifting at about 241 Ma, probably induced by counter-clockwise and clockwise movements (north and south, respectively) hinged at about 20° latitude south and taking place during t ...
... mechanism is the Alto Paraguay Triassic alkaline magmatism at the border of the Rio Apa block. This area was affected by rifting at about 241 Ma, probably induced by counter-clockwise and clockwise movements (north and south, respectively) hinged at about 20° latitude south and taking place during t ...
Insights into the structure of the upper mantle beneath the Murray
... clearly shows this region of lower velocity extending into the mantle to a depth of about 280 km. The checkerboard resolution tests [Figure 6b (ii)] indicate that this part of the model is well constrained by the data. The slices at 34.08S and 35.78S in Figure 7b also exhibit some evidence of the fa ...
... clearly shows this region of lower velocity extending into the mantle to a depth of about 280 km. The checkerboard resolution tests [Figure 6b (ii)] indicate that this part of the model is well constrained by the data. The slices at 34.08S and 35.78S in Figure 7b also exhibit some evidence of the fa ...
Why did not the Ontong Java Plateau form subaerially?
... to characterize the spatial extent of this plateau. ...
... to characterize the spatial extent of this plateau. ...
FOOT OF THE CONTINENTAL SLOPE IN ARTICLE 76
... interpret geological structure and locate the continent-ocean transition. This information is used as supporting evidence for the identification of the region of the base of the slope, or is used to demonstrate that the foot of the continental slope positions based on the maximum change in gradient ...
... interpret geological structure and locate the continent-ocean transition. This information is used as supporting evidence for the identification of the region of the base of the slope, or is used to demonstrate that the foot of the continental slope positions based on the maximum change in gradient ...
Constraints on the viscosity of the continental crust and mantle from
... crust, whereas other authors have proposed that in other regions it may also affect the upper mantle [Freed and Lin, 2001; Pollitz et al., 2000, 2001]. [6] Several authors have used transient signals in GPSderived velocities to infer the viscosity of the crust and/or mantle in various tectonic envir ...
... crust, whereas other authors have proposed that in other regions it may also affect the upper mantle [Freed and Lin, 2001; Pollitz et al., 2000, 2001]. [6] Several authors have used transient signals in GPSderived velocities to infer the viscosity of the crust and/or mantle in various tectonic envir ...
The plume head-lithosphere interactions near intra - HAL-Insu
... topography features are then used to interpret uplifts and subsidences in terms of mechanical coupling/uncoupling between different rheological layers within the lithosphere. In addition, heat and mass transfer at lithospheric depths, following the plume impact phase, is detailed and discussed in th ...
... topography features are then used to interpret uplifts and subsidences in terms of mechanical coupling/uncoupling between different rheological layers within the lithosphere. In addition, heat and mass transfer at lithospheric depths, following the plume impact phase, is detailed and discussed in th ...
Investigating Large Igneous Province Formation and
... thermo-chemical plumes, which show a lower vertical velocity component than purely thermal plumes, and thus induce lower strain rates at the base of the lithosphere. Furthermore, the new generation of numerical models incorporate��������� s�������� both a buoyant residual solid in the plume head res ...
... thermo-chemical plumes, which show a lower vertical velocity component than purely thermal plumes, and thus induce lower strain rates at the base of the lithosphere. Furthermore, the new generation of numerical models incorporate��������� s�������� both a buoyant residual solid in the plume head res ...
Metamorphic processes in the subducting slab and overlying mantle
... subduction zones. Much progress has been made towards addressing the three fundamental science themes proposed by the science plan: (1) How do forcing functions such as convergence rate and upper plate thickness regulate production of magma and fluid from the Subduction Factory? (2) How does the vol ...
... subduction zones. Much progress has been made towards addressing the three fundamental science themes proposed by the science plan: (1) How do forcing functions such as convergence rate and upper plate thickness regulate production of magma and fluid from the Subduction Factory? (2) How does the vol ...
Earth Science Chapter 18: Volcanic Activity Chapter Overview
... Volcanism describes all the processes associated with the discharge of magma, hot fluids, ash, and gases • Convergent volcanism – at oceanic-continental convergent boundaries volcanoes occur as the oceanic plate descends and the crust melts. The melting crust forms a magma that is less dense than th ...
... Volcanism describes all the processes associated with the discharge of magma, hot fluids, ash, and gases • Convergent volcanism – at oceanic-continental convergent boundaries volcanoes occur as the oceanic plate descends and the crust melts. The melting crust forms a magma that is less dense than th ...
Fig. 1 - Durham University Community
... may be in error. The seismic low velocity zone (LVZ) may be compositionally stratified with small melt fractions concentrated towards the interface with the growing lithosphere because of buoyancy. Such small melt fractions, enriched in volatiles and incompatible elements, continue to metasomatize th ...
... may be in error. The seismic low velocity zone (LVZ) may be compositionally stratified with small melt fractions concentrated towards the interface with the growing lithosphere because of buoyancy. Such small melt fractions, enriched in volatiles and incompatible elements, continue to metasomatize th ...
Eurasia spreading basin to Laptev Shelf transition: structural pattern
... Eurasia spreading basin to Laptev Shelf transition shows the gradient of three penetrations (H9805P01–H9805P03), which were approximately 350 m apart. One measurement of thermal conductivity was performed at penetration H9805P01 indicating values of 0.9–1.1 W mK−1 (see Fig. 4g). H E AT - F L O W C ...
... Eurasia spreading basin to Laptev Shelf transition shows the gradient of three penetrations (H9805P01–H9805P03), which were approximately 350 m apart. One measurement of thermal conductivity was performed at penetration H9805P01 indicating values of 0.9–1.1 W mK−1 (see Fig. 4g). H E AT - F L O W C ...
Upper mantle beneath Southeast Asia from S velocity tomography
... multiple S waves. The observed range of S velocity variations is the widest (17–18%) in the upper 150 km of the mantle. High-velocity continental roots can reach beyond the present extent of the overlying Archean-Proterozoic crust by 500 km. Beneath some Precambrian units the roots are absent, which ...
... multiple S waves. The observed range of S velocity variations is the widest (17–18%) in the upper 150 km of the mantle. High-velocity continental roots can reach beyond the present extent of the overlying Archean-Proterozoic crust by 500 km. Beneath some Precambrian units the roots are absent, which ...
rift valley - National Geographic
... Associated with the Jordan Rift Valley to the south is the Red Sea Rift. Millions of years ago, the Arabian Peninsula was connected to Africa. Seafloor spreading caused the Arabian and African plates to rift apart. The Indian Ocean flooded the rift valley between the continents, creating the Red Se ...
... Associated with the Jordan Rift Valley to the south is the Red Sea Rift. Millions of years ago, the Arabian Peninsula was connected to Africa. Seafloor spreading caused the Arabian and African plates to rift apart. The Indian Ocean flooded the rift valley between the continents, creating the Red Se ...
The Farallon-Aluk ridge collision with South America: Implications
... oceanic crust. It is highly buoyant since it is composed of hotter oceanic lithosphere, and has divergent growth vectors. Therefore, the development of a ridge-trench triple junction by the collision of a divergent ridge with a trench can be one of the most efficient mechanisms to produce subducted o ...
... oceanic crust. It is highly buoyant since it is composed of hotter oceanic lithosphere, and has divergent growth vectors. Therefore, the development of a ridge-trench triple junction by the collision of a divergent ridge with a trench can be one of the most efficient mechanisms to produce subducted o ...
Chapter 14 - Mesozoic Geology
... – covered about one-fourth of Earth's surface, – and was surrounded by Panthalassa, • a global ocean that encompassed about 300 degrees of longitude ...
... – covered about one-fourth of Earth's surface, – and was surrounded by Panthalassa, • a global ocean that encompassed about 300 degrees of longitude ...
Laboratory Title
... The continent of Zealandia, which separated from Australia 85 million years ago and stretches from New Caledonia in the north to New Zealand's subantarctic islands in the south, is now being torn apart along the transform boundary marked by the Alpine Fault. South of New Zealand the boundary becomes ...
... The continent of Zealandia, which separated from Australia 85 million years ago and stretches from New Caledonia in the north to New Zealand's subantarctic islands in the south, is now being torn apart along the transform boundary marked by the Alpine Fault. South of New Zealand the boundary becomes ...
Mantle discontinuities beneath the Deccan volcanic
... near KARD, at relatively shallow depths of about 56 km, which were interpreted to be associated with zones of weakness and lower viscosity [28] probably unrelated to the origin of DVP. ...
... near KARD, at relatively shallow depths of about 56 km, which were interpreted to be associated with zones of weakness and lower viscosity [28] probably unrelated to the origin of DVP. ...
Serpentine and the subduction zone water cycle
... release from sediments, crust, and serpentinized mantle. We find that serpentinized lithospheric mantle may not only be an important fluid source to trigger arc melting but is also an efficient ‘transport-lithology’ to recycle chemically bound water into the deeper mantle. In fact, an old slab may r ...
... release from sediments, crust, and serpentinized mantle. We find that serpentinized lithospheric mantle may not only be an important fluid source to trigger arc melting but is also an efficient ‘transport-lithology’ to recycle chemically bound water into the deeper mantle. In fact, an old slab may r ...
Seismic Investigation of the Yavapai-Mazatzal Transition Zone
... scales up to lithospheric-scale were incorporated in the Laurentia super-continent and the boundaries between these elements persisted as shallowly to steeply dipping structural and chemical boundaries, some of which appear to have been reactivated during subsequent magmatism or/and tectonic deforma ...
... scales up to lithospheric-scale were incorporated in the Laurentia super-continent and the boundaries between these elements persisted as shallowly to steeply dipping structural and chemical boundaries, some of which appear to have been reactivated during subsequent magmatism or/and tectonic deforma ...
Glossary Accommodation zone—Accommodation zone is the zone
... where offset is transferred from one fault to another (Rosendahl 1987). Active continental stage of the transform margin development—During this stage, the transform fault accommodates a displacement between the two continental plates (Wilson 1965; Freund 1974). It is linked with neighbor rift zones ...
... where offset is transferred from one fault to another (Rosendahl 1987). Active continental stage of the transform margin development—During this stage, the transform fault accommodates a displacement between the two continental plates (Wilson 1965; Freund 1974). It is linked with neighbor rift zones ...
Effects of active crustal movements on thermal structure in
... in addition to the effects of radioactive heat generation in the crust, frictional heating at plate boundaries and accretion of oceanic sediments to overriding continental plates, we numerically simulate the evolution process of the thermal structure in subduction zones. The result shows that the te ...
... in addition to the effects of radioactive heat generation in the crust, frictional heating at plate boundaries and accretion of oceanic sediments to overriding continental plates, we numerically simulate the evolution process of the thermal structure in subduction zones. The result shows that the te ...
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.