![Redalyc.Long-term evolution of subduction zones and the](http://s1.studyres.com/store/data/002278571_1-c69161baa185ad5ec76993f7c4f1e9d6-300x300.png)
Redalyc.Long-term evolution of subduction zones and the
... subduction system along the western North America continental margin (McKenzie and Morgan, 1969; Atwater, 1970, 1989). The magmatism covers a zone more than 1000 km wide. An eastward shift of igneous activity (Lindgren, 1915) took place during Late Mesozoic to Early Cenozoic times (Lipman et al., 1 ...
... subduction system along the western North America continental margin (McKenzie and Morgan, 1969; Atwater, 1970, 1989). The magmatism covers a zone more than 1000 km wide. An eastward shift of igneous activity (Lindgren, 1915) took place during Late Mesozoic to Early Cenozoic times (Lipman et al., 1 ...
tethyan evolution of turkey: a plate tectonic approach
... Palaeo-Tethyan and a Neo-Tethyan, although they partly overlap in time. The PalaeoTethyan evolution was governed by the main south-dipping (present geographic orientation) subduction zone of Palaeo-Tethys beneath northern Turkey during the PermoLiassic interval. During the Permian the entire present ...
... Palaeo-Tethyan and a Neo-Tethyan, although they partly overlap in time. The PalaeoTethyan evolution was governed by the main south-dipping (present geographic orientation) subduction zone of Palaeo-Tethys beneath northern Turkey during the PermoLiassic interval. During the Permian the entire present ...
GEOLOGIC STRUCTURE OF THE UPPERMOST OCEANIC CRUST
... intermediate- to fast-spreading ridges, which are commonly perceived as the simplest types of spreading centers—ones that are likely to conform to traditional models and to generate a geologically simple layered crust. The details of the geology of a few key areas have been accumulating over the pas ...
... intermediate- to fast-spreading ridges, which are commonly perceived as the simplest types of spreading centers—ones that are likely to conform to traditional models and to generate a geologically simple layered crust. The details of the geology of a few key areas have been accumulating over the pas ...
SESSIONE TS1.3 Processi magmatici e metamorfici nella crosta
... ABSTRACT Granitoids represent a considerable proportion of the Hercynian crustal sections exposed in Calabria. In the Sila and Serre massif the granitoids are stacked to make a pile of tabular intrusions with a cumulative thickness of 9 to 13 km. Composition typically ranges from tonalite to granite ...
... ABSTRACT Granitoids represent a considerable proportion of the Hercynian crustal sections exposed in Calabria. In the Sila and Serre massif the granitoids are stacked to make a pile of tabular intrusions with a cumulative thickness of 9 to 13 km. Composition typically ranges from tonalite to granite ...
Early Ordovician rifting of Avalonia and birth of the Rheic Ocean: U
... thereby negating any correlation with the younger volcanic arc sequences. On the Connaigre Peninsula, early arc rocks are represented by low-grade calc-alkaline rhyolite flows and pyroclastic rocks of the Tickle Point Formation that yielded a 682.8 1.6 Ma U–Pb zircon age (Swinden & Hunt 1991). Pri ...
... thereby negating any correlation with the younger volcanic arc sequences. On the Connaigre Peninsula, early arc rocks are represented by low-grade calc-alkaline rhyolite flows and pyroclastic rocks of the Tickle Point Formation that yielded a 682.8 1.6 Ma U–Pb zircon age (Swinden & Hunt 1991). Pri ...
Metamorphic processes in the subducting slab and overlying mantle
... (e.g., Abers et al., 2003; Hacker et al., 2003). Of critical importance is the measurement or calculation of shear moduli—and their variation with pressure and temperature—in crustal minerals. Studies of metamorphic rocks that reached various depths in ancient subduction zones are critical to unders ...
... (e.g., Abers et al., 2003; Hacker et al., 2003). Of critical importance is the measurement or calculation of shear moduli—and their variation with pressure and temperature—in crustal minerals. Studies of metamorphic rocks that reached various depths in ancient subduction zones are critical to unders ...
Initiation of subduction in nature and models
... The issue of induced versus spontaneous subduction initiation also remains partially controversial in both nature and within numerical models. As summarized by [5], nearly half of all active subduction zones initiated during the Cenozoic. Furthermore, all subduction zones associated with active back ...
... The issue of induced versus spontaneous subduction initiation also remains partially controversial in both nature and within numerical models. As summarized by [5], nearly half of all active subduction zones initiated during the Cenozoic. Furthermore, all subduction zones associated with active back ...
Subduction styles in the Precambrian
... Fig. 1. Initial configuration of the numerical model (see text (2.1.1) for details). White lines are isotherms shown for increments of 200 °C starting from 100 °C. Colors indicate materials (e.g. rock type or melt) which appear in subsequent figures. For the continental crust, the sediments and the ma ...
... Fig. 1. Initial configuration of the numerical model (see text (2.1.1) for details). White lines are isotherms shown for increments of 200 °C starting from 100 °C. Colors indicate materials (e.g. rock type or melt) which appear in subsequent figures. For the continental crust, the sediments and the ma ...
A preliminary Geological and Generalized Stratigraphy of Western
... 1.3. Geology of Dallol Area Although, the northern Afar Depression has been one of few places on earth that imprint a complete record of the volcano-tectonic evolution of a young ocean basin. It, however, lacks extensive geological investigations due to extremely difficult field conditions that have ...
... 1.3. Geology of Dallol Area Although, the northern Afar Depression has been one of few places on earth that imprint a complete record of the volcano-tectonic evolution of a young ocean basin. It, however, lacks extensive geological investigations due to extremely difficult field conditions that have ...
Strength of the lithosphere and strain localisation in the Baikal rift
... The geometry of the Moho and LAB has been calculated by Petit and Déverchère (2006) using band-filtering and downward continuation of the Bouguer gravity data, considering that these interfaces are located at different mean depths and thus produce different characteristic wavelengths in the Bouguer g ...
... The geometry of the Moho and LAB has been calculated by Petit and Déverchère (2006) using band-filtering and downward continuation of the Bouguer gravity data, considering that these interfaces are located at different mean depths and thus produce different characteristic wavelengths in the Bouguer g ...
The Pace of Plutonism
... cooling of the magmas from zircon crystallization to below 680 °C, respectively. Curiously, the Adamello batholith also includes a second population of titanite (nonmagmatic) intergrown with chlorite that probably grew at lower temperatures (Schoene et al. 2012). These titanite crystals are signific ...
... cooling of the magmas from zircon crystallization to below 680 °C, respectively. Curiously, the Adamello batholith also includes a second population of titanite (nonmagmatic) intergrown with chlorite that probably grew at lower temperatures (Schoene et al. 2012). These titanite crystals are signific ...
Depleted lithosphere, cold, trapped asthenosphere, and frozen melt
... geometry, we performed an inversion of P, S, and S–P seismic travel times from regional events recorded at stations from the Chile Argentina Geophysical Experiment (CHARGE). The experiment consisted of 22 broadband seismic stations deployed for 18months beginning in late 2000. This data was compleme ...
... geometry, we performed an inversion of P, S, and S–P seismic travel times from regional events recorded at stations from the Chile Argentina Geophysical Experiment (CHARGE). The experiment consisted of 22 broadband seismic stations deployed for 18months beginning in late 2000. This data was compleme ...
The role of crustal and mantle sources in the genesis of granitoids of
... identified elsewhere in the peninsula as clasts within conglomerates (Pankhurst 1983; Loske & Miller 1991; Tangeman et al. 1996). Locally, the basement underwent metamorphism, migmatization and granite emplacement during Carboniferous (c. 325 Ma) and Permian (c. 260 Ma) times. The plutonic rocks whi ...
... identified elsewhere in the peninsula as clasts within conglomerates (Pankhurst 1983; Loske & Miller 1991; Tangeman et al. 1996). Locally, the basement underwent metamorphism, migmatization and granite emplacement during Carboniferous (c. 325 Ma) and Permian (c. 260 Ma) times. The plutonic rocks whi ...
Metamorphic reworking of a high pressure–low temperature
... The Guatemala suture zone is a major east–west left-lateral strike slip boundary that separates the North American and Caribbean plates in Guatemala. The Motagua fault, the central active strand of the suture zone, underwent two major collisional events within a system otherwise dominated by strike– ...
... The Guatemala suture zone is a major east–west left-lateral strike slip boundary that separates the North American and Caribbean plates in Guatemala. The Motagua fault, the central active strand of the suture zone, underwent two major collisional events within a system otherwise dominated by strike– ...
Geochemistry and petrogenesis of extrusive rocks, dykes and high
... The island of Oldra, part of the Late Ordovician Solund-Stavfjord Ophiolite Complex of the western Norwegian Caledonides, comprises extrusive rocks, a sheeted dyke complex and high-leve! gabbros. The metabasalts are of N-MORB affinity, and their Nd isotopic composition (eNd=+7.8 to +8.4) indicates g ...
... The island of Oldra, part of the Late Ordovician Solund-Stavfjord Ophiolite Complex of the western Norwegian Caledonides, comprises extrusive rocks, a sheeted dyke complex and high-leve! gabbros. The metabasalts are of N-MORB affinity, and their Nd isotopic composition (eNd=+7.8 to +8.4) indicates g ...
Myrmekite and muscovite developed by retrograde
... indicates interesting possibilities where retrograde metamorphism causes reaction between co-existing feldspars. Thus the simple proportionality relationship implied by equation ~ may not pertain, and Shelley's (t969) objections are probably justified for particular types of myrmekite. ('Further dis ...
... indicates interesting possibilities where retrograde metamorphism causes reaction between co-existing feldspars. Thus the simple proportionality relationship implied by equation ~ may not pertain, and Shelley's (t969) objections are probably justified for particular types of myrmekite. ('Further dis ...
Pangaea to Plate Tectonics Report
... Not only does The Urantia Book say that the continents were once all connected as one land mass and that they broke up and then drifted apart, it also provides details about how this happened. Additionally, it addresses issues related to how various pressures affect the interrelationship of oceans, ...
... Not only does The Urantia Book say that the continents were once all connected as one land mass and that they broke up and then drifted apart, it also provides details about how this happened. Additionally, it addresses issues related to how various pressures affect the interrelationship of oceans, ...
Support of high elevation in the southern Basin and Range based
... summit of the MCC. In fact the average Vp/Vs measurement of all MCCs is greater (1.83) than remaining Basin and Range stations (1.73) ignoring station DSRT. Measurements at ABBY and TUC curiously exhibit equal or slightly thicker crust than the higher elevation MCCs sampled at KITT, LEMN and SQRL. T ...
... summit of the MCC. In fact the average Vp/Vs measurement of all MCCs is greater (1.83) than remaining Basin and Range stations (1.73) ignoring station DSRT. Measurements at ABBY and TUC curiously exhibit equal or slightly thicker crust than the higher elevation MCCs sampled at KITT, LEMN and SQRL. T ...
Cowie, Stonehaven
... and early summer, and especially at low tide. Rocks are displayed that tell an amazing story of an ancient ocean that was destroyed by colliding continents whose edges were then buckled to form high mountains. Eroded debris from these mountains is seen side by side across the Highland Boundary Fault ...
... and early summer, and especially at low tide. Rocks are displayed that tell an amazing story of an ancient ocean that was destroyed by colliding continents whose edges were then buckled to form high mountains. Eroded debris from these mountains is seen side by side across the Highland Boundary Fault ...
EAST AFRICAN RIFT SYSTEM
... eruptive fissures, local concentration of high activity may show up as possible geothermal targets. ...
... eruptive fissures, local concentration of high activity may show up as possible geothermal targets. ...
geologic map of the eagle a-2 quadrangle, fortymile mining district
... Chicken area. Silicified and altered regional correlatives of this unit contain epithermal gold prospects, as at Ptarmigan Hill, 10 km west of Eagle,Alaska, and Grew Creek, near Ross River, Yukon Territory (Newberry and others, 1998b). Spatial association with placer gold-bearing gravels in the Chic ...
... Chicken area. Silicified and altered regional correlatives of this unit contain epithermal gold prospects, as at Ptarmigan Hill, 10 km west of Eagle,Alaska, and Grew Creek, near Ross River, Yukon Territory (Newberry and others, 1998b). Spatial association with placer gold-bearing gravels in the Chic ...
Plate tectonics and lithosphere architecture: temporal and spatial
... Present-day. Mantle facies variation inferred from seismic (Blundell et al., 1992) and experimental data reveals (a) a thick, heterogeneous, diamond-garnet facies keel (low heat flow, high velocity anomaly) beneath the Baltic Shield; (b) thin, relatively homogeneous, garnet-spinel facies mantle (hig ...
... Present-day. Mantle facies variation inferred from seismic (Blundell et al., 1992) and experimental data reveals (a) a thick, heterogeneous, diamond-garnet facies keel (low heat flow, high velocity anomaly) beneath the Baltic Shield; (b) thin, relatively homogeneous, garnet-spinel facies mantle (hig ...
Presentation
... • an introduction to plate tectonics; • distinction between the ‘facts’ of plate tectonics and the evidence used to support plate tectonic theory; • a survey of some of the evidence supporting plate tectonic theory; • explanation of some of the hazards caused by plate tectonic processes earthquakes ...
... • an introduction to plate tectonics; • distinction between the ‘facts’ of plate tectonics and the evidence used to support plate tectonic theory; • a survey of some of the evidence supporting plate tectonic theory; • explanation of some of the hazards caused by plate tectonic processes earthquakes ...
A Geoelectric Model of the Cascadia Subduction Zone
... and other oceans. It comprises three layers: (1) a sedimentary layer 1 to 2 km thick; (2) a 1.5- to 2-km-thick layer of basalts (pillow lavas) and basaltic flows with dolerite dikes; and (3) a layer of fully crystalline igneous rocks (gabbro and ultramafic varieties) 3 to 4 km thick. The Cascade Ran ...
... and other oceans. It comprises three layers: (1) a sedimentary layer 1 to 2 km thick; (2) a 1.5- to 2-km-thick layer of basalts (pillow lavas) and basaltic flows with dolerite dikes; and (3) a layer of fully crystalline igneous rocks (gabbro and ultramafic varieties) 3 to 4 km thick. The Cascade Ran ...
The geology of the Váddás area, Troms
... Nahpojohka Group, which at c.580 Ma was intruded by a rift-type, intracratonic to marginal basin, dolerite dyke swarm and related gabbro source rocks, has been studied in detail. It is proposed that the rocks of the ¢orrovárri Nappe were deformed during a poorly understood Finnmarkian tectonometamor ...
... Nahpojohka Group, which at c.580 Ma was intruded by a rift-type, intracratonic to marginal basin, dolerite dyke swarm and related gabbro source rocks, has been studied in detail. It is proposed that the rocks of the ¢orrovárri Nappe were deformed during a poorly understood Finnmarkian tectonometamor ...
Great Lakes tectonic zone
The Great Lakes tectonic zone is bounded by South Dakota at its tip and heads northeast to south of Duluth, Minnesota, then heads east through northern Wisconsin, Marquette, Michigan, and then trends more northeasterly to skim the northern-most shores of lakes Michigan and Huron before ending in the Sudbury, Ontario, Canada, area.During the Late Archean Era the Algoman orogeny added landmass to the Superior province by volcanic activity and continental collision along a boundary that stretches from present-day South Dakota, U.S., into the Lake Huron region near Sudbury, Ontario, Canada.This crustal boundary is the Great Lakes tectonic zone. It is 1,400 km (870 mi) long, and separates the older Archean gneissic terrane to the south from younger Late Archean greenstone-granite terrane to the north.The zone is characterized by active compression during the Algoman orogeny (about 2,700 million years ago), a pulling-apart (extensional) tectonics (2,450 to 2,100 million years ago), a second compression during the Penokean orogeny (1,900 to 1,850 million years ago), a second extension during Middle Proterozoic time (1,600 million years ago) and minor reactivation during Phanerozoic time (the past 500 million years).Collision began along the Great Lakes tectonic zone (GLTZ) with the Algoman mountain-building event and continued for tens of millions of years. During the formation of the GLTZ, the gneissic Minnesota River Valley subprovince was thrust up onto the Superior province's edge as it consumed the Superior province's oceanic crust. Fragmentation of the Kenorland supercontinent began 2,450 million years ago and was completed by 2,100 million years ago. The Wyoming province is the continental landmass that is hypothesized to have rifted away from the southern Superior province portion of Kenorland, before moving rapidly west and docking with the Laurentia supercontinent 1,850 to 1,715 million years ago. Sedimentation from the GLTZ-rifting environment continued into the Penokean orogeny, which is the next major tectonic event in the Great Lakes region. Several earthquakes have been documented in Minnesota, Michigan's Upper Peninsula and Sudbury in the last 120 years along the GLTZ.