The Subductability of Continental Lithosphere
... these components could increase the negative buoyancy of the slab, promoting subduction of crustal material. Similarly, the geometry and nature (volcanic vs non-volcanic) of the colliding passive margin should exert a non-negligible influence. It is evident therefore that the final configuration and ...
... these components could increase the negative buoyancy of the slab, promoting subduction of crustal material. Similarly, the geometry and nature (volcanic vs non-volcanic) of the colliding passive margin should exert a non-negligible influence. It is evident therefore that the final configuration and ...
Lecture 46
... We can solve for the relative mass of depleted mantle. Likely answer is ~30% if BSE εNd = 0 (chondritic) but 40-100% if the Earth has εNd = 3-7, consistent with collisional erosion. Bottom line: at a minimum, melt has been extracted from a lot (~30%) or perhaps most of the mantle to form the contine ...
... We can solve for the relative mass of depleted mantle. Likely answer is ~30% if BSE εNd = 0 (chondritic) but 40-100% if the Earth has εNd = 3-7, consistent with collisional erosion. Bottom line: at a minimum, melt has been extracted from a lot (~30%) or perhaps most of the mantle to form the contine ...
Becker, T. W. - The University of Texas at Austin
... The state of stress of the lithosphere depends on many factors. Among them are the material properties, boundary conditions, surface loads and basal shear stress exerted by the underlying mantle circulation. In order to understand the relative importance from all of these contributions, it is vital ...
... The state of stress of the lithosphere depends on many factors. Among them are the material properties, boundary conditions, surface loads and basal shear stress exerted by the underlying mantle circulation. In order to understand the relative importance from all of these contributions, it is vital ...
Table 7-1 Basin classifications
... Graben structures, rift valleys and rift zones, aulocogens (on continental crust) ...
... Graben structures, rift valleys and rift zones, aulocogens (on continental crust) ...
Spreading Continents Kick-Started Plate Tectonics Plate tectonics
... that no convective stresses act on the lid, allowing us to isolate the dynamic effect of the continent. A ...
... that no convective stresses act on the lid, allowing us to isolate the dynamic effect of the continent. A ...
tectonic plates
... and the layer directly below is called the asthenosphere. Both are solid layers of rock. • The lithosphere is divided into large, moving pieces called tectonic plates. • The theory of plate tectonics explains how lithospheric plates move around on the slowflowing rock of the asthenosphere. Copyright ...
... and the layer directly below is called the asthenosphere. Both are solid layers of rock. • The lithosphere is divided into large, moving pieces called tectonic plates. • The theory of plate tectonics explains how lithospheric plates move around on the slowflowing rock of the asthenosphere. Copyright ...
seismic waves - Gordon State College
... • Plates slide past one another and no new lithosphere is created or destroyed • Most transform faults join two segments of a mid-ocean ridge • Transform faults are oriented perpendicular to mid-ocean ridge —Permits plates to move from offset ridge segments ...
... • Plates slide past one another and no new lithosphere is created or destroyed • Most transform faults join two segments of a mid-ocean ridge • Transform faults are oriented perpendicular to mid-ocean ridge —Permits plates to move from offset ridge segments ...
Subduction origin on early Earth: A hypothesis
... rheological boundaries. Fundamental, relatively sharp, focused boundaries form the essence of modern plate tectonics. Rheological and density differences play critical roles in the nature of tectonic processes of all terrestrial planets. Subduction ultimately requires plates—large tracts of crust or ...
... rheological boundaries. Fundamental, relatively sharp, focused boundaries form the essence of modern plate tectonics. Rheological and density differences play critical roles in the nature of tectonic processes of all terrestrial planets. Subduction ultimately requires plates—large tracts of crust or ...
modern and ancient incompatible element-poor adakite
... fluids to the mantle source region. The Mocha Fracture Zone of the Nazca plate, which projects beneath the Quaternary arc at the latitude of NLV, may be responsible for the elevated slab-component of NLV magmas. Oceanic transform faults commonly host serpentinized peridotite bodies, which can libera ...
... fluids to the mantle source region. The Mocha Fracture Zone of the Nazca plate, which projects beneath the Quaternary arc at the latitude of NLV, may be responsible for the elevated slab-component of NLV magmas. Oceanic transform faults commonly host serpentinized peridotite bodies, which can libera ...
Continents on the move
... Another look at plate boundaries You would probably find it easy to explain what happens at an ocean ridge on an divergent boundary. You learned about these stretching boundaries in Set 4. But what happens at convergent boundaries where tectonic plates collide? What happens when a continental plate ...
... Another look at plate boundaries You would probably find it easy to explain what happens at an ocean ridge on an divergent boundary. You learned about these stretching boundaries in Set 4. But what happens at convergent boundaries where tectonic plates collide? What happens when a continental plate ...
Shervais, J.W., Significance of Subduction
... basaltic protoliths and isotopic compositions that reflect ancient seawater alteration (e.g., MacGregor and Manton, 1986; Shervais et al, 1988; Shirey et al., 2001). The chemical and isotopic compositions of these eclogites demonstrate a supracrustal origin as oceanic crust, while their current mine ...
... basaltic protoliths and isotopic compositions that reflect ancient seawater alteration (e.g., MacGregor and Manton, 1986; Shervais et al, 1988; Shirey et al., 2001). The chemical and isotopic compositions of these eclogites demonstrate a supracrustal origin as oceanic crust, while their current mine ...
Breakthrough the Discontinuity: 21st Century Mohole
... technology must be required to complete the "21st Century Mohole". While waiting for the technological development and site survey, we propose to accomplish a "Pre-Mohole" with existing technology including off-set drilling, then proceed to the "Full-Mohole" that penetrates through normal, intact oc ...
... technology must be required to complete the "21st Century Mohole". While waiting for the technological development and site survey, we propose to accomplish a "Pre-Mohole" with existing technology including off-set drilling, then proceed to the "Full-Mohole" that penetrates through normal, intact oc ...
1 Evolution of continental crust through two Wilson
... rift initiation and evolution to passive-margin subsidence. Some components of Atlantic opening directly overprint older Iapetan extensional structures and/or AppalachianPangaean contractional structures, whereas some elements of the Atlantic rift margin cut across the older structures (Thomas, 2006 ...
... rift initiation and evolution to passive-margin subsidence. Some components of Atlantic opening directly overprint older Iapetan extensional structures and/or AppalachianPangaean contractional structures, whereas some elements of the Atlantic rift margin cut across the older structures (Thomas, 2006 ...
Age, spreading rates, and spreading asymmetry of the world`s ocean
... mapped at the time when the grid was assembled. They include parts of the southern and central eastern Indian Ocean, parts of the Late Cretaceous ocean crust in the southwest Pacific and many back-arc basins. Also, no spreading rate or spreading asymmetry grids were constructed at that time. Here we ...
... mapped at the time when the grid was assembled. They include parts of the southern and central eastern Indian Ocean, parts of the Late Cretaceous ocean crust in the southwest Pacific and many back-arc basins. Also, no spreading rate or spreading asymmetry grids were constructed at that time. Here we ...
Regional phases in continental and oceanic environments
... as a simplified representation of crustal thickness variation adjacent to a subduction zone. We have deliberately taken a simple model without the complications of the subduction zone itself so that the structure of the regional wavefield can be clearly seen. We have taken a simple homogeneous mantl ...
... as a simplified representation of crustal thickness variation adjacent to a subduction zone. We have deliberately taken a simple model without the complications of the subduction zone itself so that the structure of the regional wavefield can be clearly seen. We have taken a simple homogeneous mantl ...
︎PDF - Fabio Crameri
... lithosphere-scale weak channel maintained by such a mechanism and/or by actual weak sediment that has been advected down into the subduction zone is thought to be key in inducing realistic, single-sided subduction by providing lubrication at the plate interface [Lenardic and Kaula, 1994; Tagawa et a ...
... lithosphere-scale weak channel maintained by such a mechanism and/or by actual weak sediment that has been advected down into the subduction zone is thought to be key in inducing realistic, single-sided subduction by providing lubrication at the plate interface [Lenardic and Kaula, 1994; Tagawa et a ...
The role of magmatically driven lithospheric thickening on arc front
... long-lived and stationary arc fronts in tectonic settings where large magnitude extension occurs. We focus on the geodynamic consequences of a few interacting subduction zone components, primarily the effect of thickening or thinning the overlying plate on evolving kinematic confinement of the mantle ...
... long-lived and stationary arc fronts in tectonic settings where large magnitude extension occurs. We focus on the geodynamic consequences of a few interacting subduction zone components, primarily the effect of thickening or thinning the overlying plate on evolving kinematic confinement of the mantle ...
Shape and origin of the East-Alpine slab constrained by the
... During the last two decades teleseismic studies yielded valuable information on the structure of the upper mantle below the Alpine–Mediterranean area. Subducted oceanic lithosphere forms a broad anomaly resting on but not penetrating the 670 km discontinuity. More shallow slabs imaged below the Alpi ...
... During the last two decades teleseismic studies yielded valuable information on the structure of the upper mantle below the Alpine–Mediterranean area. Subducted oceanic lithosphere forms a broad anomaly resting on but not penetrating the 670 km discontinuity. More shallow slabs imaged below the Alpi ...
The Yellowstone Hotspot: Plume or Not?
... interaction, where a deep mantle plume slips through a gap in subducted slab material, exploits a zone of weakness in the slab, or breaks through the slab (e.g., Obrebski et al., 2010). Alternatively, an upwelling plume might slip around the exposed southern edge of the subducting Juan de Fuca slab, ...
... interaction, where a deep mantle plume slips through a gap in subducted slab material, exploits a zone of weakness in the slab, or breaks through the slab (e.g., Obrebski et al., 2010). Alternatively, an upwelling plume might slip around the exposed southern edge of the subducting Juan de Fuca slab, ...
Differential Rotation Between Lithosphere and Mantle: A
... rotation agreewith a roughly westwardrotation with a pole dippingsubductionsare alsocharacterizedby arcswith their located in the southern part of the Indian Ocean and an major convexity oriented toward the east, suggestingto be observedvelocity of a few centimeters per year. The Pacific obstacles t ...
... rotation agreewith a roughly westwardrotation with a pole dippingsubductionsare alsocharacterizedby arcswith their located in the southern part of the Indian Ocean and an major convexity oriented toward the east, suggestingto be observedvelocity of a few centimeters per year. The Pacific obstacles t ...
C 2 = C 1 + h
... Pro- and retrograde metamorphic reactions play important roles for the dynamics in orogenic belts in that they give • Changes in petrophysical properties (density structure and hence evolution of topography) • Reaction enhanced deformation (increased strain (strain-rate) in zones of reaction) • Mate ...
... Pro- and retrograde metamorphic reactions play important roles for the dynamics in orogenic belts in that they give • Changes in petrophysical properties (density structure and hence evolution of topography) • Reaction enhanced deformation (increased strain (strain-rate) in zones of reaction) • Mate ...
10. Regional Geophysics and Structural Framework of the
... accretionary prism. The oceanic crust dips gently landward toward the deformation front, with a corresponding thickening of the incoming sediment section. The maximum water depths are only about 2500 m as a consequence of the young age (5-7 Ma) of the oceanic lithosphere at the deformation front and ...
... accretionary prism. The oceanic crust dips gently landward toward the deformation front, with a corresponding thickening of the incoming sediment section. The maximum water depths are only about 2500 m as a consequence of the young age (5-7 Ma) of the oceanic lithosphere at the deformation front and ...
Subduction styles in the Precambrian
... lithology, the present values of radiogenic heat production are prescribed (H0r in Table 1; Turcotte and Schubert, 2002). Subduction is initiated by prescribing a weak fracture zone in the mantle with the rheology of wet olivine (Ranalli, 1995) and low plastic strength (internal friction coefficient ...
... lithology, the present values of radiogenic heat production are prescribed (H0r in Table 1; Turcotte and Schubert, 2002). Subduction is initiated by prescribing a weak fracture zone in the mantle with the rheology of wet olivine (Ranalli, 1995) and low plastic strength (internal friction coefficient ...
Oceanic trench
The oceanic trenches are hemispheric-scale long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few mm to over ten cm per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to a volcanic island arc, and about 200 km (120 mi) from a volcanic arc. Oceanic trenches typically extend 3 to 4 km (1.9 to 2.5 mi) below the level of the surrounding oceanic floor. The greatest ocean depth to be sounded is in the Challenger Deep of the Mariana Trench, at a depth of 11,034 m (36,201 ft) below sea level. Oceanic lithosphere moves into trenches at a global rate of about 3 km2/yr.