Generation of new continental crust by sublithospheric silicic
... MgO= 2 wt.%), which is rich in incompatible elements, and a mafic lower layer (SiO2 = 52 wt.%; MgO= 6 wt.%), which is variably depleted in incompatible elements (Rudnick and Gao, 2003). The possibility that both layers are linked by processes of magma fractionation is explored here by considering bat ...
... MgO= 2 wt.%), which is rich in incompatible elements, and a mafic lower layer (SiO2 = 52 wt.%; MgO= 6 wt.%), which is variably depleted in incompatible elements (Rudnick and Gao, 2003). The possibility that both layers are linked by processes of magma fractionation is explored here by considering bat ...
A. M. Celâl ŞENGÖR, Boris A. NATAL`IN, Gürsel
... The Altaids are one of the largest superorogenic complexes in the world in which two genetically closely related orogenic complexes ended up generating much of northern Asia during the Palaeozoic and the early and medial Mesozoic. This immense superorogenic complex evolved as a consequence of the de ...
... The Altaids are one of the largest superorogenic complexes in the world in which two genetically closely related orogenic complexes ended up generating much of northern Asia during the Palaeozoic and the early and medial Mesozoic. This immense superorogenic complex evolved as a consequence of the de ...
A geological model for the structure of ridge segments in slow
... The axes of mid-oceanridges are offset by discontinuities and Laughton, 1977], and adjacentspreadingaxes often overwhich divide the oceancrust into spreadingsegments(Figure lap, with crustal ridges or septa cutting acrossthe discontinu1) [Macdonald et al., 1991]. First-order discontinuities in ities ...
... The axes of mid-oceanridges are offset by discontinuities and Laughton, 1977], and adjacentspreadingaxes often overwhich divide the oceancrust into spreadingsegments(Figure lap, with crustal ridges or septa cutting acrossthe discontinu1) [Macdonald et al., 1991]. First-order discontinuities in ities ...
Formation and Exhumation of Ultrahigh
... crustal rocks back to Earth’s surface without exceeding the moderate temperatures (<800 °C) observed in most continental UHP terranes. The need for such cool temperatures to be maintained by either continued, deeper-level subduction refrigeration or rapid, near-adiabatic exhumation has led to the ge ...
... crustal rocks back to Earth’s surface without exceeding the moderate temperatures (<800 °C) observed in most continental UHP terranes. The need for such cool temperatures to be maintained by either continued, deeper-level subduction refrigeration or rapid, near-adiabatic exhumation has led to the ge ...
Ridge subduction and porphyry copper
... connected to adakites [4–6, 62, 63]. In China, the Tongling, Shaxi, Dexing porphyry or skarn Cu deposits are all associated with adakite or adakitic rocks [12, 46, 47, 64–66]. It has even been proposed that adakite should be taken as an exploration target for Cu deposits [67]. The genetic connection ...
... connected to adakites [4–6, 62, 63]. In China, the Tongling, Shaxi, Dexing porphyry or skarn Cu deposits are all associated with adakite or adakitic rocks [12, 46, 47, 64–66]. It has even been proposed that adakite should be taken as an exploration target for Cu deposits [67]. The genetic connection ...
Geophysical assessment of migration and storage conditions of
... The detection of these reservoirs using electromagnetic measurements highlights the fact that electrical studies can be a powerful tool to investigate volcanic plumbing systems in subduction. ...
... The detection of these reservoirs using electromagnetic measurements highlights the fact that electrical studies can be a powerful tool to investigate volcanic plumbing systems in subduction. ...
Genesis of the Neogene to Quaternary volcanism in the Carpathian
... Northern Pannonian Basin. However, the crustal component gradually decreased with time, which is consistent with magmatic activity in a continuously thinning continental plate. Calc-alkaline volcanism along the Eastern Carpathians was mostly postcollisional and could have been related to slab break- ...
... Northern Pannonian Basin. However, the crustal component gradually decreased with time, which is consistent with magmatic activity in a continuously thinning continental plate. Calc-alkaline volcanism along the Eastern Carpathians was mostly postcollisional and could have been related to slab break- ...
Subduction cycles under western North America during the
... have been studied in more detail than anywhere else in the world. Radiometric ages for tens of thousands of rocks provide extensive mileposts for times of change in tectonic and magmatic conditions. Increasingly detailed structural studies are finding many specific periods of deformation and changes ...
... have been studied in more detail than anywhere else in the world. Radiometric ages for tens of thousands of rocks provide extensive mileposts for times of change in tectonic and magmatic conditions. Increasingly detailed structural studies are finding many specific periods of deformation and changes ...
Relations between sedimentary basins and petroleum
... the lithosphere does have a net rotation relative to the mantle, with a mean westward direction. This is particularly evident if we consider the velocity at which the Pacific travels WNW, so high that the sum of the movements of all the other plates cannot compensate for it, thus determining a resid ...
... the lithosphere does have a net rotation relative to the mantle, with a mean westward direction. This is particularly evident if we consider the velocity at which the Pacific travels WNW, so high that the sum of the movements of all the other plates cannot compensate for it, thus determining a resid ...
PDF 51 - The Open University
... book The Age of the Earth. Importantly, his second famous book Principles of Physical Geology did not follow the traditional viewpoints and concluded with a chapter describing continental drift. 1940-1960 The complexity of ocean floor topography was realised through improvements to sonar equipment d ...
... book The Age of the Earth. Importantly, his second famous book Principles of Physical Geology did not follow the traditional viewpoints and concluded with a chapter describing continental drift. 1940-1960 The complexity of ocean floor topography was realised through improvements to sonar equipment d ...
eastern european alpine system and the carpathian
... km). The polarity of subduction is uncertain, but eastward dipping imbricate thrusts in the Vardar zone suggest eastward subduction, however the east dip may be the result of later deformational events. If the volcanic rocks are related to subduction, volcanism must have taken place in an oceanic te ...
... km). The polarity of subduction is uncertain, but eastward dipping imbricate thrusts in the Vardar zone suggest eastward subduction, however the east dip may be the result of later deformational events. If the volcanic rocks are related to subduction, volcanism must have taken place in an oceanic te ...
From oceanic plateaus to allochthonous terranes: Numerical
... cross-section (4000 km by 1400 km) Fig. 1. The rectangular grid with 1361∗ 351 nodal points is non-uniform and contains a (1000 km wide) high-resolution area of 1 km ∗ 1 km in the centre of the domain. The rest of the model remains at a lower resolution (10 ∗ 10 km). The oceanic crust contains an oc ...
... cross-section (4000 km by 1400 km) Fig. 1. The rectangular grid with 1361∗ 351 nodal points is non-uniform and contains a (1000 km wide) high-resolution area of 1 km ∗ 1 km in the centre of the domain. The rest of the model remains at a lower resolution (10 ∗ 10 km). The oceanic crust contains an oc ...
Continent formation through time
... & Scholl 2010). Continental arcs such as those of the Andes feature continental growth through mag- matic addition, with the long-term rates of magma production being similar to that in island arcs (Clift et al. 2009; DeCelles et al. 2009). Magma pro- duction is increased in continental arcs during ...
... & Scholl 2010). Continental arcs such as those of the Andes feature continental growth through mag- matic addition, with the long-term rates of magma production being similar to that in island arcs (Clift et al. 2009; DeCelles et al. 2009). Magma pro- duction is increased in continental arcs during ...
garwin_et_al_2005 Au-Cu Cenozoic magmatic arcs SE Asia
... with north-northwest–trending rift axes, which were truncated by northeast transform faults (Yamazaki and Yuasa, 1998). The latest Pliocene to Quaternary rifting is manifested in the central part of the arc by several grabens with northtrending axes located behind the volcanic front (Taylor, 1992). ...
... with north-northwest–trending rift axes, which were truncated by northeast transform faults (Yamazaki and Yuasa, 1998). The latest Pliocene to Quaternary rifting is manifested in the central part of the arc by several grabens with northtrending axes located behind the volcanic front (Taylor, 1992). ...
Summary of Northeast Asia geodynamics and tectonics*
... A series of linear island arcs or continental margin arcs and tectonically-linked (companion) subduction zones, and (or) fore-arc and back-arc basins that formed in a major tectonic event during a relatively narrow geologic time span. The collages of igneous arcs and companion subduction zone terran ...
... A series of linear island arcs or continental margin arcs and tectonically-linked (companion) subduction zones, and (or) fore-arc and back-arc basins that formed in a major tectonic event during a relatively narrow geologic time span. The collages of igneous arcs and companion subduction zone terran ...
Laramide crustal thickening event in the Rocky Mountain Foreland
... and Great Plains at up to 2 km average elevation. The same shear tractions that Brewer et al. [1980] invoked to cause the Wind River range overthrust may also have dragged and transported ductile lower crust from within the Sevier orogen in the Southwest, and emplaced it under ...
... and Great Plains at up to 2 km average elevation. The same shear tractions that Brewer et al. [1980] invoked to cause the Wind River range overthrust may also have dragged and transported ductile lower crust from within the Sevier orogen in the Southwest, and emplaced it under ...
Lower crustal earthquakes near the Ethiopian rift induced by
... and are especially concentrated near zones with the largest fraction of partial melt, likely sourced from the mantle. Although magmatism outside the MER rift axis may currently be particularly concentrated near volcanic centers, geophysical data suggest a small fraction of aligned partial melt is wi ...
... and are especially concentrated near zones with the largest fraction of partial melt, likely sourced from the mantle. Although magmatism outside the MER rift axis may currently be particularly concentrated near volcanic centers, geophysical data suggest a small fraction of aligned partial melt is wi ...
GSA TODAY - Geological Society of America
... the Coast Range Ophiolite to three different tectonic settings: (1) Dickinson infers “backarc” seafloor spreading behind a migratory east-facing intraoceanic island arc, which collided with the west-facing Sierran arc along the continental margin (as intervening oceanic lithosphere was consumed), to ...
... the Coast Range Ophiolite to three different tectonic settings: (1) Dickinson infers “backarc” seafloor spreading behind a migratory east-facing intraoceanic island arc, which collided with the west-facing Sierran arc along the continental margin (as intervening oceanic lithosphere was consumed), to ...
An ultraslow-spreading class of ocean ridge
... ridges consist of linked magmatic and amagmatic accretionary ridge segments. The amagmatic segments are a previously unrecognized class of accretionary plate boundary structure and can assume any orientation, with angles relative to the spreading direction ranging from orthogonal to acute. These ama ...
... ridges consist of linked magmatic and amagmatic accretionary ridge segments. The amagmatic segments are a previously unrecognized class of accretionary plate boundary structure and can assume any orientation, with angles relative to the spreading direction ranging from orthogonal to acute. These ama ...
An ultraslow-spreading class of ocean ridge
... ridges consist of linked magmatic and amagmatic accretionary ridge segments. The amagmatic segments are a previously unrecognized class of accretionary plate boundary structure and can assume any orientation, with angles relative to the spreading direction ranging from orthogonal to acute. These ama ...
... ridges consist of linked magmatic and amagmatic accretionary ridge segments. The amagmatic segments are a previously unrecognized class of accretionary plate boundary structure and can assume any orientation, with angles relative to the spreading direction ranging from orthogonal to acute. These ama ...
Origin and consequences of western Mediterranean subduction
... Lustrino et al., 2011], suggesting that subduction below Iberia and southern France was active since at least late Eocene time. This was followed by the inception of widespread overriding plate extension, opening the Liguro-Provençal basin since ~30 Ma and the Valencia basin several million years th ...
... Lustrino et al., 2011], suggesting that subduction below Iberia and southern France was active since at least late Eocene time. This was followed by the inception of widespread overriding plate extension, opening the Liguro-Provençal basin since ~30 Ma and the Valencia basin several million years th ...
Protoridge_Three-Dimensional Seismic Imaging of a
... young fault belts (Fig. 1), with a north-northeast trend that is oblique to the overall northeast trend of the rift. The segments are separated from one another by #20 km in a right-lateral en echelon pattern, and show little correlation with the border faults (Ebinger and Casey, 2001). The extensio ...
... young fault belts (Fig. 1), with a north-northeast trend that is oblique to the overall northeast trend of the rift. The segments are separated from one another by #20 km in a right-lateral en echelon pattern, and show little correlation with the border faults (Ebinger and Casey, 2001). The extensio ...
Thickness of the lithosphere beneath Turkey and
... receiver functions (Angus et al., 2006). They consider this lithospheric thickness to be anomalously thin and interpret this structure to be the remnant of the detachment of an oceanic slab. Further evidence for a thin lithosphere overlying hot and partially molten asthenospheric material beneath ea ...
... receiver functions (Angus et al., 2006). They consider this lithospheric thickness to be anomalously thin and interpret this structure to be the remnant of the detachment of an oceanic slab. Further evidence for a thin lithosphere overlying hot and partially molten asthenospheric material beneath ea ...
OKINAWA TROUGH: ORIGIN OF A BACK
... High seismicity is associated with the length of Okinawa Trough and the Ryukyu Arc and Trench (Barazangi and Dorman, 1969). Katsumata and Sykes (1969) demonstrated that the seismic activity is concentrated along a northwestward-dipping plane extending from the region of the Ryukyu Trench beneath the ...
... High seismicity is associated with the length of Okinawa Trough and the Ryukyu Arc and Trench (Barazangi and Dorman, 1969). Katsumata and Sykes (1969) demonstrated that the seismic activity is concentrated along a northwestward-dipping plane extending from the region of the Ryukyu Trench beneath the ...
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 ...
Izu-Bonin-Mariana Arc
The Izu-Bonin-Mariana (IBM) arc system is an outstanding example of a plate tectonic convergent boundary. IBM extends over 2800 km south from Tokyo, Japan, to beyond Guam, and includes the Izu Islands, Bonin Islands, and Mariana Islands; much more of the IBM arc system is submerged below sealevel. The IBM arc system lies along the eastern margin of the Philippine Sea Plate in the Western Pacific Ocean. It is most famous for being the site of the deepest gash in Earth's solid surface, the Challenger Deep in the Mariana Trench. The IBM arc system formed as a result of subduction of the western Pacific plate. The IBM arc system now subducts mid-Jurassic to Early Cretaceous lithosphere, with younger lithosphere in the north and older lithosphere in the south, including the oldest (~170 million years old, or Ma) oceanic crust. Subduction rates vary from ~2 cm (1 inch) per year in the south to 6 cm (~2.5 inches) in the north. The volcanic islands that comprise these island arcs are thought to have been formed from the release of volatiles (steam from trapped water, and other gases) being released from the subducted plate, as it reached sufficient depth for the temperature to cause release of these materials. The associated trenches are formed as the oldest (most western) part of the Pacific plate crust increases in density with age, and because of this process finally reaches its lowest point just as it subducts under the crust to the west of it.The IBM arc system is an excellent example of an intra-oceanic convergent margin (IOCM). IOCMs are built on oceanic crust and contrast fundamentally with island arc built on continental crust, such as Japan or the Andes. Because IOCM crust is thinner, denser, and more refractory than that beneath Andean-type margins, study of IOCM melts and fluids allows more confident assessment of mantle-to-crust fluxes and processes than is possible for Andean-type convergent margins. Because IOCMs are far removed from continents they are not affected by the large volume of alluvial and glacial sediments. The consequent thin sedimentary cover makes it much easier to study arc infrastructure and determine the mass and composition of subducted sediments. Active hydrothermal systems found on the submarine parts of IOCMs give us a chance to study how many of earth's important ore deposits formed.