The Seismic Structure of Island Arc Crust
... sources, but the arc will reestablish itself at the appropriate location above the slab as the back-arc spreading centres migrate away (Hussong and Uyeda 1981). If rifting occurs in the forearc, then the remnant arc will be uncommonly wide as seems to be the case with the Lau Ridge west of the Tonga ...
... sources, but the arc will reestablish itself at the appropriate location above the slab as the back-arc spreading centres migrate away (Hussong and Uyeda 1981). If rifting occurs in the forearc, then the remnant arc will be uncommonly wide as seems to be the case with the Lau Ridge west of the Tonga ...
Ancient recycled mantle lithosphere in the Hawaiian plume: Osmium
... Generation of basaltic oceanic crust at divergent plate boundaries (i.e. mid oceanic ridges) and recycling of the lithospheric plate back into the Earth's mantle via subduction at convergent plate boundaries play a principle role in the generation of long-lived chemical and isotopic heterogeneities ...
... Generation of basaltic oceanic crust at divergent plate boundaries (i.e. mid oceanic ridges) and recycling of the lithospheric plate back into the Earth's mantle via subduction at convergent plate boundaries play a principle role in the generation of long-lived chemical and isotopic heterogeneities ...
New Zealand`s Continental Shelf and UNCLOS
... Prompted by the desire to settle, in a spirit of mutual understanding and co-operation, all issues relating to the law of the sea, the international community has adopted the United Nations Convention on the Law of the Sea (UNCLOS). The Convention establishes the concept of the exclusive economic zo ...
... Prompted by the desire to settle, in a spirit of mutual understanding and co-operation, all issues relating to the law of the sea, the international community has adopted the United Nations Convention on the Law of the Sea (UNCLOS). The Convention establishes the concept of the exclusive economic zo ...
Microbiology of seaMouNts
... associated with seamounts. The volcanically active portion of these undersea mountains hosts a remarkably diverse range of unusual microbial habitats, from black smokers rich in sulfur to cooler, diffuse, iron-rich hydrothermal vents. As such, seamounts potentially represent hotspots of microbial di ...
... associated with seamounts. The volcanically active portion of these undersea mountains hosts a remarkably diverse range of unusual microbial habitats, from black smokers rich in sulfur to cooler, diffuse, iron-rich hydrothermal vents. As such, seamounts potentially represent hotspots of microbial di ...
Seismic velocity structure of the rifted margin of the eastern Grand
... continental crust or oceanic crust. On the landward side of the Iberian margin, the zone of continental crust that is thinned to less than 10 km (hereinafter referred to as thin continental crust) is just 40 km wide in the southern Iberia Abyssal Plain [Dean et al., 2000]. In contrast, the combined ...
... continental crust or oceanic crust. On the landward side of the Iberian margin, the zone of continental crust that is thinned to less than 10 km (hereinafter referred to as thin continental crust) is just 40 km wide in the southern Iberia Abyssal Plain [Dean et al., 2000]. In contrast, the combined ...
Zuni–Bandera volcanism, Rio Grande, USA — Melt formation in
... emplaced during metasomatic events (McMillan, 1998; McMillan et al., 2000), the lithosphere becomes an exhausted reservoir for melt generation and the asthenospheric mantle begins to dominate as a source for continental volcanism (McMillan, 1998; McMillan ...
... emplaced during metasomatic events (McMillan, 1998; McMillan et al., 2000), the lithosphere becomes an exhausted reservoir for melt generation and the asthenospheric mantle begins to dominate as a source for continental volcanism (McMillan, 1998; McMillan ...
Geophysical Constraints on Mantle Composition
... Mathematical inversion of large numbers of travel times, observed at a variety of distances between source (earthquake) and receiver (seismometer), results in velocity profiles that represent the variation of VP and VS (or Vj) as functions of depth. The changes in velocities across seismic ‘disconti ...
... Mathematical inversion of large numbers of travel times, observed at a variety of distances between source (earthquake) and receiver (seismometer), results in velocity profiles that represent the variation of VP and VS (or Vj) as functions of depth. The changes in velocities across seismic ‘disconti ...
1 Origin and geodynamic relationships of the Late Miocene to
... In the Pannonian Basin, eruption of alkali basaltic magmas started in the westernmost margin, where two outcrops are known, at Pauliberg and at Oberpullendorf in Burgenland ...
... In the Pannonian Basin, eruption of alkali basaltic magmas started in the westernmost margin, where two outcrops are known, at Pauliberg and at Oberpullendorf in Burgenland ...
Flood basalts, continental breakup and the dispersal of
... Received: 18 October 2000 – Revised: 27 December 2001 – Accepted: 4 March 2002 ...
... Received: 18 October 2000 – Revised: 27 December 2001 – Accepted: 4 March 2002 ...
Crust recycling in the sources of two parallel volcanic chains in
... geochemical and isotopic compositions, whereas the tholeiites may have been contaminated by the crust or the lithospheric mantle because of their more enriched isotopic compositions (Peng et al., 1986; Song et al., 1990; Xu et al., 2005). Tang et al. (2006) proposed that the geochemical signatures o ...
... geochemical and isotopic compositions, whereas the tholeiites may have been contaminated by the crust or the lithospheric mantle because of their more enriched isotopic compositions (Peng et al., 1986; Song et al., 1990; Xu et al., 2005). Tang et al. (2006) proposed that the geochemical signatures o ...
A geological model for the structure of ridge segments in slow
... both slow and fast spreadingcrust are transformfaults; they 1990]. Off-axis, the traces of these discontinuities are modernormallyoffset the ridge axis by 30 km or more (>0.5-2 m.y. ately developedbathymetricvalleys which contain a series of age offset), are orientedin the directionof relative plate ...
... both slow and fast spreadingcrust are transformfaults; they 1990]. Off-axis, the traces of these discontinuities are modernormallyoffset the ridge axis by 30 km or more (>0.5-2 m.y. ately developedbathymetricvalleys which contain a series of age offset), are orientedin the directionof relative plate ...
Platinum-group elements (PGE) and rhenium in marine sediments
... Abstract—The nature of Re–platinum-group element (PGE; Pt, Pd, Ir, Os, Ru) transport in the marine environment was investigated by means of marine sediments at and across the Cretaceous–Tertiary boundary (KTB) at two hemipelagic sites in Europe and two pelagic sites in the North and South Pacific. A ...
... Abstract—The nature of Re–platinum-group element (PGE; Pt, Pd, Ir, Os, Ru) transport in the marine environment was investigated by means of marine sediments at and across the Cretaceous–Tertiary boundary (KTB) at two hemipelagic sites in Europe and two pelagic sites in the North and South Pacific. A ...
Trace Element and Isotope Geochemistry of the Volcanic Rocks of
... ho6pb/2O4pb 19.7-20-2), in which all of the Sr and Pb ratios The island of Bequia lies in the southern section of are higher and Nd ratios are lower than those of the IHS. The the Lesser Antillean arc (Fig. 1), which formed along IDS is also characterized by high dla0 values, up to 7-6 in the easter ...
... ho6pb/2O4pb 19.7-20-2), in which all of the Sr and Pb ratios The island of Bequia lies in the southern section of are higher and Nd ratios are lower than those of the IHS. The the Lesser Antillean arc (Fig. 1), which formed along IDS is also characterized by high dla0 values, up to 7-6 in the easter ...
Types of Metamorphism
... - The yielded rocks suffered deformation and recrystallization, and exhibit penetrative fabric with preferred orientation of mineral grains. They could suffered phases of crystallization and deformation - At higher P-T conditions, partial to complete melting may accompanied and ...
... - The yielded rocks suffered deformation and recrystallization, and exhibit penetrative fabric with preferred orientation of mineral grains. They could suffered phases of crystallization and deformation - At higher P-T conditions, partial to complete melting may accompanied and ...
Ophiolite concept and its evolution
... instrumental in the formulation of the ophiolite model and the ophiolite-ocean crust analogy within the framework of the new plate tectonic theory. This analogy was confirmed at the first Penrose Conference on ophiolites in 1972, whereby an ideal ophiolite sequence was defined to have a layer-cake p ...
... instrumental in the formulation of the ophiolite model and the ophiolite-ocean crust analogy within the framework of the new plate tectonic theory. This analogy was confirmed at the first Penrose Conference on ophiolites in 1972, whereby an ideal ophiolite sequence was defined to have a layer-cake p ...
Flow and melting of a heterogeneous mantle: 2. Implications for a
... mid-ocean ridges driven passively by plate spreading generates a bresidual mantle columnQ (RMC) nearly uniform in width. (b) Mantle plume flow beneath rigid plate generates a bresidual mantle cylinderQ (RMC) that widens with depth. Relative to mid-ocean ridges, mantle plumes tend to sample proportio ...
... mid-ocean ridges driven passively by plate spreading generates a bresidual mantle columnQ (RMC) nearly uniform in width. (b) Mantle plume flow beneath rigid plate generates a bresidual mantle cylinderQ (RMC) that widens with depth. Relative to mid-ocean ridges, mantle plumes tend to sample proportio ...
Geophysical Journal International - E
... structure of the crust and lithospheric mantle. This was one of the motivations of the TopoIberia project (http://iberarray.ictja.csic.es/), a large-scale multidisciplinary research initiative to investigate the Earth’s structure and dynamics in Iberia and northern Morocco. In this work we analyse d ...
... structure of the crust and lithospheric mantle. This was one of the motivations of the TopoIberia project (http://iberarray.ictja.csic.es/), a large-scale multidisciplinary research initiative to investigate the Earth’s structure and dynamics in Iberia and northern Morocco. In this work we analyse d ...
Static and dynamic support of western United States topography
... be expected, e.g. given the trade-off between interface depth and velocity. Yet, overall crustal layer thickness patterns agree well; the total correlation between LM and LPG is r = 0.88. The continental Moho is more complicated than the oceanic Moho. However, to a first approximation, the geophysica ...
... be expected, e.g. given the trade-off between interface depth and velocity. Yet, overall crustal layer thickness patterns agree well; the total correlation between LM and LPG is r = 0.88. The continental Moho is more complicated than the oceanic Moho. However, to a first approximation, the geophysica ...
Chapter 1- INTRODUCTION 1.1. Mantle Rocks This study is
... Seismology, together with experimental petrology, studies on meteorites, and mathematical models have allowed to know the deep Earth’s structure and chemistry, characterized by a metal core composed mainly by iron, nickel, and sulfur, and divided in a solid inner core and an outer liquid core, whic ...
... Seismology, together with experimental petrology, studies on meteorites, and mathematical models have allowed to know the deep Earth’s structure and chemistry, characterized by a metal core composed mainly by iron, nickel, and sulfur, and divided in a solid inner core and an outer liquid core, whic ...
PDF (Chapter 23. The Upper Mantle)
... subsequently found to contain a high-velocity lid and a low-velocity zone (LVZ), generally associated with the asthenosphere. Region C, the mantle transition region (TR), was subsequently found to contain two abrupt seismic discontinuities near the depths of 410 and 650 km, and a region of high and ...
... subsequently found to contain a high-velocity lid and a low-velocity zone (LVZ), generally associated with the asthenosphere. Region C, the mantle transition region (TR), was subsequently found to contain two abrupt seismic discontinuities near the depths of 410 and 650 km, and a region of high and ...
Static and dynamic support of western United States
... The continental Moho is more complicated than the oceanic Moho. However, to a first approximation, the geophysically defined crust–mantle boundary, the depth where vP jumps above 7.6 km/s, can be associated with a change in composition. Therefore, we assume that the major, shallow impedance contrast ...
... The continental Moho is more complicated than the oceanic Moho. However, to a first approximation, the geophysically defined crust–mantle boundary, the depth where vP jumps above 7.6 km/s, can be associated with a change in composition. Therefore, we assume that the major, shallow impedance contrast ...
Fig. 1 - Durham University Community
... The important thing in science is not so much to obtain new facts as to discover new ways of thinking about them. ― Sir William Bragg. 1. Introduction The incompatible element depleted nature of mid-ocean ridge basalts (MORB) is widely accepted as reflecting their depleted mantle source. Because ocea ...
... The important thing in science is not so much to obtain new facts as to discover new ways of thinking about them. ― Sir William Bragg. 1. Introduction The incompatible element depleted nature of mid-ocean ridge basalts (MORB) is widely accepted as reflecting their depleted mantle source. Because ocea ...
Weakness of the lower continental crust: a condition for
... into a thicker granitic–gneissic upper crust and an ultramafic residue that forms a new seismic Moho. The resulting crust is both thinner and more sialic (Meissner, 1989). In this paper, we define delamination as the decoupling process of continental lower crust and upper mantle from the overlying c ...
... into a thicker granitic–gneissic upper crust and an ultramafic residue that forms a new seismic Moho. The resulting crust is both thinner and more sialic (Meissner, 1989). In this paper, we define delamination as the decoupling process of continental lower crust and upper mantle from the overlying c ...
PDF (Chapter 9. The Source Region)
... mantle. The composition of the MORB reservoir can therefore range from eclogite to garnet peridotite, depending on depth and the extent of partial melting and crystal fractionation occurring prior to magma separation. The bulk of the material erupting at oceanic islands and as continental flood basa ...
... mantle. The composition of the MORB reservoir can therefore range from eclogite to garnet peridotite, depending on depth and the extent of partial melting and crystal fractionation occurring prior to magma separation. The bulk of the material erupting at oceanic islands and as continental flood basa ...
PDF (Chapter 8. Chemical Composition of the Mantle)
... of differentiation, or separation, processes. In some geochemical models it is assumed that large parts of the Earth escaped partial melting, or melt removal, and are therefore still "primitive." Some petrological models assume that melts being delivered to the Earth's surface are samples from previ ...
... of differentiation, or separation, processes. In some geochemical models it is assumed that large parts of the Earth escaped partial melting, or melt removal, and are therefore still "primitive." Some petrological models assume that melts being delivered to the Earth's surface are samples from previ ...
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.