Experimental tests of simple models for the dynamics
... Diffuse plate boundaries, which are zones of deformation hundreds to thousands of kilometres wide, occur in both continental and oceanic lithosphere. Here we build on our prior work in which we use analytical and numerical models to investigate the dynamics of diffuse oceanic plate boundaries assumi ...
... Diffuse plate boundaries, which are zones of deformation hundreds to thousands of kilometres wide, occur in both continental and oceanic lithosphere. Here we build on our prior work in which we use analytical and numerical models to investigate the dynamics of diffuse oceanic plate boundaries assumi ...
"postorogenie" magmatism
... uplift, one result of which is to produce externally directed buoyancy forces that oppose those driving convergence (e.g., Turcotte, 1983). This could result from increased topography built up by compressional deformation, although this would not explain the thermal pulse. Thickening of the lithosph ...
... uplift, one result of which is to produce externally directed buoyancy forces that oppose those driving convergence (e.g., Turcotte, 1983). This could result from increased topography built up by compressional deformation, although this would not explain the thermal pulse. Thickening of the lithosph ...
Deep seismic reflection profiling of Archean cratons
... mantle reflections accommodate 10s of km, 100s km, or 1000s of km of displacement • Appear to be significant structures associated with accretion of “terranes” • By analogy with modern examples, mantle reflections are often interpreted as indicators of subduction ...
... mantle reflections accommodate 10s of km, 100s km, or 1000s of km of displacement • Appear to be significant structures associated with accretion of “terranes” • By analogy with modern examples, mantle reflections are often interpreted as indicators of subduction ...
Global Prevalence of Double Benioff Zones
... represent internal deformation of actively sinking lithosphere as inclined zones of seismicity connecting shallow earthquakes near the trench with earthquakes deep in the mantle. The mechanism for any seismicity below ~70-km depth is a matter of ongoing debate because of the need to overcome high co ...
... represent internal deformation of actively sinking lithosphere as inclined zones of seismicity connecting shallow earthquakes near the trench with earthquakes deep in the mantle. The mechanism for any seismicity below ~70-km depth is a matter of ongoing debate because of the need to overcome high co ...
Sierra Nevada uplift - University of Missouri
... velocity field, the top boundary is defined as the base of the brittle crust, and the flow rate within the brittle crust is set to zero. The left side is a far-distance boundary, the effects of which on the flow field are proven to be negligible. The model assumes local isostasy. The simulations sta ...
... velocity field, the top boundary is defined as the base of the brittle crust, and the flow rate within the brittle crust is set to zero. The left side is a far-distance boundary, the effects of which on the flow field are proven to be negligible. The model assumes local isostasy. The simulations sta ...
Lithospheric buoyancy forces in Africa from a thin sheet approach
... (e.g., McKenzie 1978; Wernicke 1981; Lister et al. 1986; Whitmarsh et al. 2001), which assume that lithospheric thinning and crustal extension are driven by far-field stresses from plate motions. However, a number of observations in the East African Rift (EAR), the divergent boundary between the Nub ...
... (e.g., McKenzie 1978; Wernicke 1981; Lister et al. 1986; Whitmarsh et al. 2001), which assume that lithospheric thinning and crustal extension are driven by far-field stresses from plate motions. However, a number of observations in the East African Rift (EAR), the divergent boundary between the Nub ...
Becker, TW - Semantic Scholar
... To examine the mantle drag contributions due to different buoyancy force distributions, we use 3-D, spherical mantle flow computations (Hager and O'Connell, 1981). To model mantle circulation, we solve the infinite Prandtl number, Stokes equation for incompressible fluid flow (Boussinesq approximation) ...
... To examine the mantle drag contributions due to different buoyancy force distributions, we use 3-D, spherical mantle flow computations (Hager and O'Connell, 1981). To model mantle circulation, we solve the infinite Prandtl number, Stokes equation for incompressible fluid flow (Boussinesq approximation) ...
On the shallow origin of hotspots and the westward drift of the
... motions on Earth and it influences greatly models of mantle dynamics. If the origin of Pacific intraplate hotspots is in the asthenosphere, what triggers the extraction of the extra melt? Why are the hotspots isolated, scattered, and sporadic? Their tracks suggest relatively stationary sources in th ...
... motions on Earth and it influences greatly models of mantle dynamics. If the origin of Pacific intraplate hotspots is in the asthenosphere, what triggers the extraction of the extra melt? Why are the hotspots isolated, scattered, and sporadic? Their tracks suggest relatively stationary sources in th ...
Notes and Discussions RICHARD H. SILLITOE Institute de
... melting at progressively deeper levels on subduction zones which dipped eastward beneath the continent; the metals subsequently ascended as components of calc-alkaline magma. Initially, the metals were released from the mantle at the East Pacific Rise, transported to the margins of the Pacific basin ...
... melting at progressively deeper levels on subduction zones which dipped eastward beneath the continent; the metals subsequently ascended as components of calc-alkaline magma. Initially, the metals were released from the mantle at the East Pacific Rise, transported to the margins of the Pacific basin ...
Seismic Hazards in Mid-Willamette Valley
... The largest and most widespread earthquakes are those generated from subduction zones. They tend to range in magnitude 8-9 on the Richter scale and can cause severe damage and fatalities along the entire range of the subduction zone. Although, Oregon hasn’t had subduction zone earthquake in historic ...
... The largest and most widespread earthquakes are those generated from subduction zones. They tend to range in magnitude 8-9 on the Richter scale and can cause severe damage and fatalities along the entire range of the subduction zone. Although, Oregon hasn’t had subduction zone earthquake in historic ...
Unit 2 Student Parent Eve
... tropical storms to increase in magnitude. Storms could also last for longer than they currently do, perhaps leading to storms combining to form even large storm systems. Temperature increase could also climate patterns such as El Nino events. ...
... tropical storms to increase in magnitude. Storms could also last for longer than they currently do, perhaps leading to storms combining to form even large storm systems. Temperature increase could also climate patterns such as El Nino events. ...
Magma-compensated crustal thinning in continental rift zones
... average velocities in the lower crust and uppermost mantle are lower below the Kenya rift than the BRZ, which may be due to high temperatures20. Reverberative seismic reflectivity below the rift zones may be caused by intermixed layering of primarily olivine- and pyroxene-rich rocks with layers of p ...
... average velocities in the lower crust and uppermost mantle are lower below the Kenya rift than the BRZ, which may be due to high temperatures20. Reverberative seismic reflectivity below the rift zones may be caused by intermixed layering of primarily olivine- and pyroxene-rich rocks with layers of p ...
the january 25th, 1999 earthquake in the coffee growing region of
... Figure 1. Major tectonic features in the north western corner of South America. Red arrows show velocity vectors measured with GPS (Mora, 1995). The length of the arrows is proportional to the measured rate of displacement per year. Recent studies have been successful in measuring present tectonic d ...
... Figure 1. Major tectonic features in the north western corner of South America. Red arrows show velocity vectors measured with GPS (Mora, 1995). The length of the arrows is proportional to the measured rate of displacement per year. Recent studies have been successful in measuring present tectonic d ...
A Melt Extraction From The Mantle Beneath Mid-Ocean Ridges Peter Kelemen
... s the oceanic plates move apart at midocean ridges, rocks from Earth’s mantle, far below, rise to fill the void, mostly via slow plastic flow. As the rock approaches the top of its journey, however, partial melting occurs, so that the upper 6 kilometers of oceanic crust are composed of melts, which ...
... s the oceanic plates move apart at midocean ridges, rocks from Earth’s mantle, far below, rise to fill the void, mostly via slow plastic flow. As the rock approaches the top of its journey, however, partial melting occurs, so that the upper 6 kilometers of oceanic crust are composed of melts, which ...
The origin and occurrence of
... mantle convection would be considerably sluggish (Montesi, 2000), inhibiting plume generation. Yet distinct episodes of early magmatic/tectonic activity that declines with time from early explosive volcanism evolving into steady growth of fissures, shield and cone volcanoes (Anderson et al. 2004). T ...
... mantle convection would be considerably sluggish (Montesi, 2000), inhibiting plume generation. Yet distinct episodes of early magmatic/tectonic activity that declines with time from early explosive volcanism evolving into steady growth of fissures, shield and cone volcanoes (Anderson et al. 2004). T ...
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 ...
Book - School of Geosciences
... Foley, S.F., S. Buhre, and D. E. Jacob, 2008: Evolution of the Archaean Crust by Delamination and Shallow Subduction. Nature, v. 421, 249252. Foley, S., M. Tiepolo, and R. Vannucci, 2002: Growth of early continental crust controlled by melting of amphibolite in subduction zones. Nature v. 417, 837-8 ...
... Foley, S.F., S. Buhre, and D. E. Jacob, 2008: Evolution of the Archaean Crust by Delamination and Shallow Subduction. Nature, v. 421, 249252. Foley, S., M. Tiepolo, and R. Vannucci, 2002: Growth of early continental crust controlled by melting of amphibolite in subduction zones. Nature v. 417, 837-8 ...
Lesson-Answers-for-U..
... 1. The deeper you go below Earth’s surface, the higher the temperature is. 2. The deeper you go below Earth’s surface, the higher the pressure is. 3. The pressure increases because of the weight of the overlying rocks. C. Using Earthquake Waves 1. Scientists learn about Earth’s interior by studying ...
... 1. The deeper you go below Earth’s surface, the higher the temperature is. 2. The deeper you go below Earth’s surface, the higher the pressure is. 3. The pressure increases because of the weight of the overlying rocks. C. Using Earthquake Waves 1. Scientists learn about Earth’s interior by studying ...
Do faults trigger folding in the lithosphere
... on the possibility of folding in highly faulted media. In this study, we demonstrate that folding can "survive" faulting and that both processes may develop concurrently, so that faulting may serve as a mechanism of folding in the brittle domain. We support this hypothesis by direct numerical modeli ...
... on the possibility of folding in highly faulted media. In this study, we demonstrate that folding can "survive" faulting and that both processes may develop concurrently, so that faulting may serve as a mechanism of folding in the brittle domain. We support this hypothesis by direct numerical modeli ...
Nugget
... Central Range Fault System: High precision GPS measurements collected by previous workers in the Central Range indicate they are the focus of slip between the Caribbean plate to the north and the South American plate the the south. The low, rolling topography of the Central Range Mountains are likel ...
... Central Range Fault System: High precision GPS measurements collected by previous workers in the Central Range indicate they are the focus of slip between the Caribbean plate to the north and the South American plate the the south. The low, rolling topography of the Central Range Mountains are likel ...
10. Crustal Structure of the Japan Trench: The Effect of Subduction
... planes migrate upward into the overlying continental edge, causing removal of material from its base. This tectonic erosion causes subsidence and landward retreat of the continental edge. INTRODUCTION ...
... planes migrate upward into the overlying continental edge, causing removal of material from its base. This tectonic erosion causes subsidence and landward retreat of the continental edge. INTRODUCTION ...
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.