Equatorial Segment of the Mid-Atlantic Ridge: initial results of the
... (Geological Institute of the Academy of Sciences, USSR) between 1988 and 1991. On the basis of the results obtained, the participants in the expeditions concluded that the numerous faults which intersect the equatorial part of the Mid-Atlantic ridge are of varying ages and relate differently to the ...
... (Geological Institute of the Academy of Sciences, USSR) between 1988 and 1991. On the basis of the results obtained, the participants in the expeditions concluded that the numerous faults which intersect the equatorial part of the Mid-Atlantic ridge are of varying ages and relate differently to the ...
Global Correlations of Ocean Ridge Basalt Chemistry with Axial
... first-order MORB compositional variation on a global scale. A progressively more enriched (or less depleted) fertile peridotite source (i.e. high Al2O3 and Na2O, and low CaO/Al2O3) beneath deep ridges ensures a greater amount of modal garnet (high Al2O3) and higher jadeite/diopside ratios in clinopy ...
... first-order MORB compositional variation on a global scale. A progressively more enriched (or less depleted) fertile peridotite source (i.e. high Al2O3 and Na2O, and low CaO/Al2O3) beneath deep ridges ensures a greater amount of modal garnet (high Al2O3) and higher jadeite/diopside ratios in clinopy ...
Origin of carbonatites in the South Qinling orogen:
... Bell and Tilton, 2001, 2002). At present, the prevailing view is that these magmas are derived from a lithospheric source affected by asthenospheric upwelling or plumes involving deeper parts of the mantle (e.g., Bell and Tilton, 2001; Tolstikhin et al., 2002). This conventional isotopic framework is ...
... Bell and Tilton, 2001, 2002). At present, the prevailing view is that these magmas are derived from a lithospheric source affected by asthenospheric upwelling or plumes involving deeper parts of the mantle (e.g., Bell and Tilton, 2001; Tolstikhin et al., 2002). This conventional isotopic framework is ...
Workshop Report - Consortium for Ocean Leadership
... the integration of mantle geochemistry and rock physics. There was considerable discussion of the origin and consequences of focused viscous deformation along mantle shear zones, with application to melting during shear heating, and the mechanism of intermediate depth earthquakes. Many participants, ...
... the integration of mantle geochemistry and rock physics. There was considerable discussion of the origin and consequences of focused viscous deformation along mantle shear zones, with application to melting during shear heating, and the mechanism of intermediate depth earthquakes. Many participants, ...
Hafnium isotope evidence for slab melt contributions in the Central
... et al., 2008), although the same types of observations have also been used to argue for crustal assimilation (e.g., Siebe et al., 2004; Schaaf et al., 2005; Torres-Alvarado et al., 2011). However these studies did not report Hf isotope ratios which, as we show here, add important supporting evidence ...
... et al., 2008), although the same types of observations have also been used to argue for crustal assimilation (e.g., Siebe et al., 2004; Schaaf et al., 2005; Torres-Alvarado et al., 2011). However these studies did not report Hf isotope ratios which, as we show here, add important supporting evidence ...
True Polar Wander: Linking Deep and Shallow
... alternative paleomagnetic method for constraining paleo longitude, relative to the arbitrary meridian of a presumed-equatorial TPW axis (Kirschvink et a/ (1997) and see subsequent sections)o ...
... alternative paleomagnetic method for constraining paleo longitude, relative to the arbitrary meridian of a presumed-equatorial TPW axis (Kirschvink et a/ (1997) and see subsequent sections)o ...
Behavior of subducting sediments beneath an arc under a high
... sulfur will also be partitioned into the melt rather than into minerals during the sediment melting and the formation of the Setouchi magmas. As a result, the bulk distribution coefficient of Pb should be lowered and never be increased with the existence of sulfur in the sediment melt because Pb is ...
... sulfur will also be partitioned into the melt rather than into minerals during the sediment melting and the formation of the Setouchi magmas. As a result, the bulk distribution coefficient of Pb should be lowered and never be increased with the existence of sulfur in the sediment melt because Pb is ...
Calcium isotopic composition of mantle xenoliths and minerals from
... 1987; Zhao et al., 2000; Kusky et al., 2001). The NCC consists of two Archean blocks separated by a 1.8 Ga Proterozoic orogenic belt (Zhao et al., 2000). The YC is mainly Proterozoic which may have experienced multi-stage reworking of Archean crustal materials as indicated by zircon U–Pb age and Hf ...
... 1987; Zhao et al., 2000; Kusky et al., 2001). The NCC consists of two Archean blocks separated by a 1.8 Ga Proterozoic orogenic belt (Zhao et al., 2000). The YC is mainly Proterozoic which may have experienced multi-stage reworking of Archean crustal materials as indicated by zircon U–Pb age and Hf ...
Origin of Mesoproterozoic A-type granites in Laurentia
... Fig. 1. Map of southern North America showing major Precambrian crustal provinces (after [1,6,20]) and locations of dated Mesoproterozoic granitoids (white circles). Mesoproterozoic granites are known from outcrop and, particularly in the mid-continent region, subsurface drilling. Sampled granites o ...
... Fig. 1. Map of southern North America showing major Precambrian crustal provinces (after [1,6,20]) and locations of dated Mesoproterozoic granitoids (white circles). Mesoproterozoic granites are known from outcrop and, particularly in the mid-continent region, subsurface drilling. Sampled granites o ...
as a PDF
... on a 5 -axis universal stage equipped with a proper upper hemisphere and slide for fabric analyses. Usually 100 olivine grains were selected for orientation from each specimen. Each grain was located on the photograph and rotations of the universal stage axes and positions of the olivine axes after ...
... on a 5 -axis universal stage equipped with a proper upper hemisphere and slide for fabric analyses. Usually 100 olivine grains were selected for orientation from each specimen. Each grain was located on the photograph and rotations of the universal stage axes and positions of the olivine axes after ...
Structure and Serpentinization of the Subducting Cocos Plate
... profiles show that bending stresses can exceed the strength of the oceanic lithosphere, causing a reduction of the flexural rigidity near convergent plate boundaries [Caldwell et al., 1976]. Compression in the lower half of the subducting plate may manifest itself as ductile shortening [McNutt and M ...
... profiles show that bending stresses can exceed the strength of the oceanic lithosphere, causing a reduction of the flexural rigidity near convergent plate boundaries [Caldwell et al., 1976]. Compression in the lower half of the subducting plate may manifest itself as ductile shortening [McNutt and M ...
PDF
... influence of the revolving and rupture toward the left of the violent earthquake, after the 2001 Kunlun Mountain Pass West Ms8.1 earthquake. We then analyzed the Kunlun Mountain Pass West Ms8.1 earthquake and its scope of influence (see area encircled by the bold green line in Fig. 2, which is in th ...
... influence of the revolving and rupture toward the left of the violent earthquake, after the 2001 Kunlun Mountain Pass West Ms8.1 earthquake. We then analyzed the Kunlun Mountain Pass West Ms8.1 earthquake and its scope of influence (see area encircled by the bold green line in Fig. 2, which is in th ...
The Cretaceous and Cenozoic tectonic evolution of
... given rise to numerous controversies that include the accretionary history of Sundaland and the enigmatic tectonic origin of the proto-South China Sea. We assimilate a diversity of geological and geophysical observations into a new regional plate model, coupled to a global model, to address these de ...
... given rise to numerous controversies that include the accretionary history of Sundaland and the enigmatic tectonic origin of the proto-South China Sea. We assimilate a diversity of geological and geophysical observations into a new regional plate model, coupled to a global model, to address these de ...
Roberts et al., 2013, Basin Modeling
... •• forward modelling the kinematics of break-up. Finally we aim to bring together the complete rifting/break-up process within a single forward kinematic model, built upon earlier work by Kusznir et al. (2005) and Kusznir & Karner (2007), incorporating observations from the previous analyses in its ...
... •• forward modelling the kinematics of break-up. Finally we aim to bring together the complete rifting/break-up process within a single forward kinematic model, built upon earlier work by Kusznir et al. (2005) and Kusznir & Karner (2007), incorporating observations from the previous analyses in its ...
Lithosphere delamination in continental collisional orogens: A
... initial weak zone is placed between the pro-plate and retro-plate, which is applied to locate the initial convergence, not for initiating delamination. The initial continental lithosphere includes a 20 km thick upper crust, a 15 km thick lower crust, a 65 km thick lithospheric mantle, and the subjac ...
... initial weak zone is placed between the pro-plate and retro-plate, which is applied to locate the initial convergence, not for initiating delamination. The initial continental lithosphere includes a 20 km thick upper crust, a 15 km thick lower crust, a 65 km thick lithospheric mantle, and the subjac ...
Determination of fault friction from reactivation of
... because the local stress state associated with these complexities may affect the angle at which outer-slope faulting occurs (Massell, 2002; Mortera-Gutierrez et al., 2003). This worldwide data set shows that the transition angle from reactivation of abyssal-hill faults to formation of new faults is ...
... because the local stress state associated with these complexities may affect the angle at which outer-slope faulting occurs (Massell, 2002; Mortera-Gutierrez et al., 2003). This worldwide data set shows that the transition angle from reactivation of abyssal-hill faults to formation of new faults is ...
Manea et al., 2006. - Centro de Geociencias
... the small cubes will expand/contract by a different amount. Since the slab continuity must be satisfied, thermal stresses arise in this case. Such stresses can be separated in two parts (see Boley and Weiner (1997), p. 277): the first part is due to thermal expansion/ contraction in areas with large ...
... the small cubes will expand/contract by a different amount. Since the slab continuity must be satisfied, thermal stresses arise in this case. Such stresses can be separated in two parts (see Boley and Weiner (1997), p. 277): the first part is due to thermal expansion/ contraction in areas with large ...
Ocean Basin Evolution and Global
... 1981, Kirkwood et al. 1999). Africa is commonly used as the anchor plate at the top of the plate hierarchy due to its central position within Pangea (see Torsvik et al. 2008). The rotation tree underneath Africa expresses a cascading set of relationships describing the relative motion between the pl ...
... 1981, Kirkwood et al. 1999). Africa is commonly used as the anchor plate at the top of the plate hierarchy due to its central position within Pangea (see Torsvik et al. 2008). The rotation tree underneath Africa expresses a cascading set of relationships describing the relative motion between the pl ...
Geophysical Journal International - E
... The Gibraltar arc and surrounding areas are a complex tectonic region and its tectonic evolution since Miocene is still under debate. Knowledge of its lithospheric structure will help to understand the mechanisms that produced extension and westward motion of the Alboran domain, simultaneously with ...
... The Gibraltar arc and surrounding areas are a complex tectonic region and its tectonic evolution since Miocene is still under debate. Knowledge of its lithospheric structure will help to understand the mechanisms that produced extension and westward motion of the Alboran domain, simultaneously with ...
The Upper Mantle Geoid: Implications for Continental Structure and
... (degree/order up to 2159) is shown in Figure 1a. This geoid is the height of the geoid above/below the chosen reference ellipsoid, so the polar flattening and equatorial bulge (ellipticity) of the geoid doesn’t show in (Figure 1a) because this field is the difference between a (near) ellipsoidal ge ...
... (degree/order up to 2159) is shown in Figure 1a. This geoid is the height of the geoid above/below the chosen reference ellipsoid, so the polar flattening and equatorial bulge (ellipticity) of the geoid doesn’t show in (Figure 1a) because this field is the difference between a (near) ellipsoidal ge ...
Palaeocene–Recent plate boundaries in the NE Atlantic and the
... 2000; Mjelde et al. 2007). Because of the position of a stationary Iceland plume (Lawver & Müller 1994) closer to western Greenland than to the future location of breakup, more complex models have been proposed to explain how a mantle plume might have affected and possible triggered the breakup and ...
... 2000; Mjelde et al. 2007). Because of the position of a stationary Iceland plume (Lawver & Müller 1994) closer to western Greenland than to the future location of breakup, more complex models have been proposed to explain how a mantle plume might have affected and possible triggered the breakup and ...
Polarized plate tectonics
... (Pyrenees). This rift, started by the anticlockwise Cretaceous rotation of Iberia, aborted since its axis is far from being orthogonal to the mantle flow direction and it is almost contemporary with the formation of the Pyrenees. Another example of aborted rift is the Benue basin, in Centralwestern ...
... (Pyrenees). This rift, started by the anticlockwise Cretaceous rotation of Iberia, aborted since its axis is far from being orthogonal to the mantle flow direction and it is almost contemporary with the formation of the Pyrenees. Another example of aborted rift is the Benue basin, in Centralwestern ...
Crustal thickening and lateral extrusion during the Indo
... (Fig. 3). The southern boundary moves northward at 40 mm/yr at the western end of the Indian indenter front, with a 0.22°/Myr counter clockwise rotation around a pole at the western end of the indenter. This is an approximation of the trajectories of the Indian plate derived from marine magnetic ano ...
... (Fig. 3). The southern boundary moves northward at 40 mm/yr at the western end of the Indian indenter front, with a 0.22°/Myr counter clockwise rotation around a pole at the western end of the indenter. This is an approximation of the trajectories of the Indian plate derived from marine magnetic ano ...
evidence from Th, Sr and Pb isotope data for Tonga
... are produced when these fluids reach mantle that is hot enough to melt. However, the rate at which these processes occur are not well understood. Recent ...
... are produced when these fluids reach mantle that is hot enough to melt. However, the rate at which these processes occur are not well understood. Recent ...
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.