Thematic Article A bathymetric overview of the Mariana forearc
... Abstract Bathymetric data at a 200-m contour interval for the entire Mariana forearc, from south of 13°N to 25°N, permits the ®rst comprehensive overview of this feature. The Mariana forearc represents a sediment-starved end-member. The forearc in its southern and central sections is divisible into ...
... Abstract Bathymetric data at a 200-m contour interval for the entire Mariana forearc, from south of 13°N to 25°N, permits the ®rst comprehensive overview of this feature. The Mariana forearc represents a sediment-starved end-member. The forearc in its southern and central sections is divisible into ...
Lower Continental Crust. - UCSB Earth Science
... OF CONTINENTAL CRUST Earth’s continental crust is widely believed to be andesitic to dacitic, with 57 to 66 wt% SiO2 (e.g., Rudnick & Gao 2003, 2014), distinct from mafic oceanic crust, with 48 to 52 wt% SiO2 , and from upper mantle residual peridotites, with <46 wt% SiO2 . Compared with oceanic crus ...
... OF CONTINENTAL CRUST Earth’s continental crust is widely believed to be andesitic to dacitic, with 57 to 66 wt% SiO2 (e.g., Rudnick & Gao 2003, 2014), distinct from mafic oceanic crust, with 48 to 52 wt% SiO2 , and from upper mantle residual peridotites, with <46 wt% SiO2 . Compared with oceanic crus ...
Mantle Convection in the Earth and Planets - U
... • dramatic improvements in computational power that have made possible the construction of realistic numerical models of mantle convection in three-dimensional spherical geometry; • spacecraft missions to Venus (Magellan), the Moon (Clementine and Lunar Prospector), Mars (Mars Global Surveyor), and ...
... • dramatic improvements in computational power that have made possible the construction of realistic numerical models of mantle convection in three-dimensional spherical geometry; • spacecraft missions to Venus (Magellan), the Moon (Clementine and Lunar Prospector), Mars (Mars Global Surveyor), and ...
ARTICLE IN PRESS - Do plumes exist?
... The kinematics of subduction zones shows a variety of settings that can provide clues for dynamic understandings. Two reference frames are used here to describe the simple 2D kinematics of subduction zones. In the first, the upper plate is assumed fixed, whereas in the second frame upper and lower p ...
... The kinematics of subduction zones shows a variety of settings that can provide clues for dynamic understandings. Two reference frames are used here to describe the simple 2D kinematics of subduction zones. In the first, the upper plate is assumed fixed, whereas in the second frame upper and lower p ...
Garnet: Common Mineral, Uncommonly Useful
... from its place in the deep Earth, up through the crust, The dark red crystals that frequently adorn common and to its applications in society. Wood, Kiseeva, and Matzen begin with a discussion of the largest reservoir mica schists are garnet (FIG. 1A). The purple-red hue that of garnet in the planet ...
... from its place in the deep Earth, up through the crust, The dark red crystals that frequently adorn common and to its applications in society. Wood, Kiseeva, and Matzen begin with a discussion of the largest reservoir mica schists are garnet (FIG. 1A). The purple-red hue that of garnet in the planet ...
Subduction kinematics and dynamic constraints
... The kinematics of subduction zones shows a variety of settings that can provide clues for dynamic understandings. Two reference frames are used here to describe the simple 2D kinematics of subduction zones. In the first, the upper plate is assumed fixed, whereas in the second frame upper and lower p ...
... The kinematics of subduction zones shows a variety of settings that can provide clues for dynamic understandings. Two reference frames are used here to describe the simple 2D kinematics of subduction zones. In the first, the upper plate is assumed fixed, whereas in the second frame upper and lower p ...
Subduction kinematics and dynamic constraints
... The kinematics of subduction zones shows a variety of settings that can provide clues for dynamic understandings. Two reference frames are used here to describe the simple 2D kinematics of subduction zones. In the first, the upper plate is assumed fixed, whereas in the second frame upper and lower p ...
... The kinematics of subduction zones shows a variety of settings that can provide clues for dynamic understandings. Two reference frames are used here to describe the simple 2D kinematics of subduction zones. In the first, the upper plate is assumed fixed, whereas in the second frame upper and lower p ...
Seamounts – characteristics, formation, mineral deposits and
... Indo-Eurasian collision events are of the latter type (Das et al., 2007). Along the East Pacific Rise seamounts mostly occur within 5-15km and rarely further than 50km away from the axis. As new ones form, their number per unit area increases with distance from the MOR. At times, the apparent volcan ...
... Indo-Eurasian collision events are of the latter type (Das et al., 2007). Along the East Pacific Rise seamounts mostly occur within 5-15km and rarely further than 50km away from the axis. As new ones form, their number per unit area increases with distance from the MOR. At times, the apparent volcan ...
accepted manuscript
... and density changes due to metamorphic transforms in LP-HP range and the associated partial melting should also play a certain role (Yamato et al., 2008), but the impact of UHP transforms on subduction may be of minor importance (Toussaint et al., 2004a), specifically if one remembers that some UHP ...
... and density changes due to metamorphic transforms in LP-HP range and the associated partial melting should also play a certain role (Yamato et al., 2008), but the impact of UHP transforms on subduction may be of minor importance (Toussaint et al., 2004a), specifically if one remembers that some UHP ...
H2O subduction beyond arcs
... generation depths because they lack K2O. Chert and carbonate are responsible for minimal H2O subduction, whereas clay-rich and terrigenous sediments stabilize several hydrous phases at low temperature, resulting in significant postarc slab H2O flux in cold and hot slabs. Continental crust also subdu ...
... generation depths because they lack K2O. Chert and carbonate are responsible for minimal H2O subduction, whereas clay-rich and terrigenous sediments stabilize several hydrous phases at low temperature, resulting in significant postarc slab H2O flux in cold and hot slabs. Continental crust also subdu ...
Chapter 7
... not all olivine-olivine interfaces (fig 5.14). The absence of films along some interfaces in the hotpressed material is similar to the observations by Cmíral (1998) and Cmíral et al. (1998) that melt films occur along many, but not all olivine grain interfaces in both deformed and statically anneale ...
... not all olivine-olivine interfaces (fig 5.14). The absence of films along some interfaces in the hotpressed material is similar to the observations by Cmíral (1998) and Cmíral et al. (1998) that melt films occur along many, but not all olivine grain interfaces in both deformed and statically anneale ...
Mechanisms of continental subduction and exhumation of HP and
... 2009). However, both, the mechanisms of continental convergence and of exhumation of HP/UHP material are still very much in debate, and the ideas on the interpretation of metamorphic data and mechanisms of convergence require further investigation. In particular, for each given context it should be ...
... 2009). However, both, the mechanisms of continental convergence and of exhumation of HP/UHP material are still very much in debate, and the ideas on the interpretation of metamorphic data and mechanisms of convergence require further investigation. In particular, for each given context it should be ...
Transfer of melts in the sub-arc mantle: Insights from high
... (Massif du Sud) is one of the largest coherent ophiolitic bodies in the world, comparable with some ophiolites in Oman (Semail, Wadi Tayin, Aswad, Fizh). It also presents the largest surface area of exposed mantle in the world and has the specificity to still remain attached to its non-obducted ocea ...
... (Massif du Sud) is one of the largest coherent ophiolitic bodies in the world, comparable with some ophiolites in Oman (Semail, Wadi Tayin, Aswad, Fizh). It also presents the largest surface area of exposed mantle in the world and has the specificity to still remain attached to its non-obducted ocea ...
Alps vs. Apennines - Dipartimento di Scienze della Terra
... oceanic subduction and the development of an Andean-type margin (Carmignani et al., 1994). The oceanic subduction ended with the collision between Gondwana-Armorica in Early Carboniferous time and the Variscan Belt was later dissected by late Variscan low angle normal faults, which were accompanied ...
... oceanic subduction and the development of an Andean-type margin (Carmignani et al., 1994). The oceanic subduction ended with the collision between Gondwana-Armorica in Early Carboniferous time and the Variscan Belt was later dissected by late Variscan low angle normal faults, which were accompanied ...
Temporal variation in relative zircon abundance throughout Earth
... calculate accurate estimates of the mean and standard error of the mean for each independent variable of interest. The primary forcings on zircon abundance over Gyr timescales are illustrated in Figure 1a as averages for igneous whole rock samples preserved in the present-day continental crust. Over ...
... calculate accurate estimates of the mean and standard error of the mean for each independent variable of interest. The primary forcings on zircon abundance over Gyr timescales are illustrated in Figure 1a as averages for igneous whole rock samples preserved in the present-day continental crust. Over ...
Melt migration beneath mid-ocean ridges
... adiabatically ascending partially molten mantle (Kelemen & Dick 1995; Kelemen et al. 1995b). The second mechanism suggests that the accumulated strain associated with passive mantle £ow beneath the spreading centre results in an anisotropic permeability, so that melt can be e¡ectively focused within ...
... adiabatically ascending partially molten mantle (Kelemen & Dick 1995; Kelemen et al. 1995b). The second mechanism suggests that the accumulated strain associated with passive mantle £ow beneath the spreading centre results in an anisotropic permeability, so that melt can be e¡ectively focused within ...
Controls on back-arc basin formation
... [1] The relationship between subduction and back-arc spreading has been well known since the early days of plate tectonics. However, the reasons why back-arc basins are associated with some subduction systems but not all has remained elusive. We examine the kinematic controls on subduction and back- ...
... [1] The relationship between subduction and back-arc spreading has been well known since the early days of plate tectonics. However, the reasons why back-arc basins are associated with some subduction systems but not all has remained elusive. We examine the kinematic controls on subduction and back- ...
nature and composition of the continental crust
... may contain rocks in the amphibolite facies, which are also found in surface outcrop or as xenoliths. Amphibolite facies rocks may also be important in the lowermost crust in areas of high water flux (such as in island arc settings where hydrous oceanic lithosphere is subducted and dewatered [e.g., ...
... may contain rocks in the amphibolite facies, which are also found in surface outcrop or as xenoliths. Amphibolite facies rocks may also be important in the lowermost crust in areas of high water flux (such as in island arc settings where hydrous oceanic lithosphere is subducted and dewatered [e.g., ...
Yin and yang of continental crust creation and destruction by plate
... Mature continental crust is compositionally layered and can be subdivided into upper continental crust (∼20 km thick) of approximately granodioritic composition and lower, mafic crust (∼20 km thick), separated by a Conrad discontinuity that is well to weakly formed (Christensen and Mooney 1995; Rudn ...
... Mature continental crust is compositionally layered and can be subdivided into upper continental crust (∼20 km thick) of approximately granodioritic composition and lower, mafic crust (∼20 km thick), separated by a Conrad discontinuity that is well to weakly formed (Christensen and Mooney 1995; Rudn ...
Evolution of the continental crust
... estimated from the compositions of model new crust and the upper continental crust19. Calculations reveal that the upper crust reflects ,14% partial melting, or the analogous amount of fractional crystallization, of average new basaltic crust (Table 1). Inevitably, the residual composition is very d ...
... estimated from the compositions of model new crust and the upper continental crust19. Calculations reveal that the upper crust reflects ,14% partial melting, or the analogous amount of fractional crystallization, of average new basaltic crust (Table 1). Inevitably, the residual composition is very d ...
An olivine-free mantle source of Hawaiian shield
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
An olivine-free mantle source of Hawaiian shield basalts
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
Orogens and slabs vs. their direction of subduction
... the viscosity value at the 670 km discontinuity between upper and lower mantle ŽHager, 1990. make the mantle adjacent to the seismically detectable slab an isolated system, with inhibited communication among eastern and western sectors of the slab, and the upper and lower mantle underneath. This sup ...
... the viscosity value at the 670 km discontinuity between upper and lower mantle ŽHager, 1990. make the mantle adjacent to the seismically detectable slab an isolated system, with inhibited communication among eastern and western sectors of the slab, and the upper and lower mantle underneath. This sup ...
1 Imaging the transition from flat to normal subduction: Variations in
... result of vertical smearing of low velocity anomalies in the crust down into the mantle, resulting ...
... result of vertical smearing of low velocity anomalies in the crust down into the mantle, resulting ...
Not Getting the Drift - Personal webpages at NTNU
... oceanic crust was thought to be the same as continental crust, only at lower elevation. Marine sediments and fossils now form high mountains; they had clearly risen from below the sea. Entire continents seemed to have once been covered by marine sediments with marine fossils. It was natural to think ...
... oceanic crust was thought to be the same as continental crust, only at lower elevation. Marine sediments and fossils now form high mountains; they had clearly risen from below the sea. Entire continents seemed to have once been covered by marine sediments with marine fossils. It was natural to think ...
Post-glacial rebound
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Post-glacial rebound (sometimes called continental rebound) is the rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period, through a process known as isostatic depression. Post-glacial rebound and isostatic depression are different parts of a process known as either glacial isostasy, glacial isostatic adjustment, or glacioisostasy. Glacioisostasy is the solid Earth deformation associated with changes in ice mass distribution. The most obvious and direct affects of post-glacial rebound are readily apparent in northern Europe (especially Scotland, Estonia, Latvia, Fennoscandia, and northern Denmark), Siberia, Canada, the Great Lakes of Canada and the United States, the coastal region of the US state of Maine, parts of Patagonia, and Antarctica. However, through processes known as ocean siphoning and continental levering, the effects of post-glacial rebound on sea-level are felt globally far from the locations of current and former ice sheets.