![Late-orogenic heating during exhumation: Alpine PTt trajectories](http://s1.studyres.com/store/data/003877635_1-fe2d3c9bbfa034e8c8489589e1db294a-300x300.png)
Late-orogenic heating during exhumation: Alpine PTt trajectories
... a rate of about 1 cm/yr [22]. The Gran Paradiso massif underwent HP metamorphism at about 525‡C and 1.4 GPa [4], equivalent to a depth of about 50 km (Fig. 2). The age of this HP metamorphism is inferred to be 43 Ma from Rb-Sr white mica dating (Me¡an-Main, pers. commun.). The rocks cooled during in ...
... a rate of about 1 cm/yr [22]. The Gran Paradiso massif underwent HP metamorphism at about 525‡C and 1.4 GPa [4], equivalent to a depth of about 50 km (Fig. 2). The age of this HP metamorphism is inferred to be 43 Ma from Rb-Sr white mica dating (Me¡an-Main, pers. commun.). The rocks cooled during in ...
Continental crust generated in oceanic arcs
... Subduction of the Galápagos tracks resulted in lavas enriched in incompatible elements with Galápagos isotopic compositions8,9 (Fig. 1). A shift from dominantly basaltic to more andesitic compositions (for example, increase in SiO2 and K2 O, Fig. 2), reaching continental crust values2 , represents a ...
... Subduction of the Galápagos tracks resulted in lavas enriched in incompatible elements with Galápagos isotopic compositions8,9 (Fig. 1). A shift from dominantly basaltic to more andesitic compositions (for example, increase in SiO2 and K2 O, Fig. 2), reaching continental crust values2 , represents a ...
The Patrimonial Value of the Betic Ophiolites: Rocks from the
... Betic Cordillera (SE Spain), intercalated between two crustal units named Caldera (below) and Sabinas (above). A comprehensive review of the petrological, geochemical and geochronological characteristics of the Betic ophiolites shows notable similarities with other MORB-type ophiolites from the Alps ...
... Betic Cordillera (SE Spain), intercalated between two crustal units named Caldera (below) and Sabinas (above). A comprehensive review of the petrological, geochemical and geochronological characteristics of the Betic ophiolites shows notable similarities with other MORB-type ophiolites from the Alps ...
NWGS Olympics
... large folds have ever been found, and fold axes are very steeply inclined (read vertical-axis folds). The western portion of the subduction complex appears cut by both high- and low-angle faults. Synclines stand put. even on satellite imagery, and can usually be mapped through with ease/ Anticlines ...
... large folds have ever been found, and fold axes are very steeply inclined (read vertical-axis folds). The western portion of the subduction complex appears cut by both high- and low-angle faults. Synclines stand put. even on satellite imagery, and can usually be mapped through with ease/ Anticlines ...
Crustal Structure at the Continental Margin South of South Africa
... the Atlantic Ocean is a rifted margin, but facing the Indian Ocean is a 1200 km long margin offset. With this study it is hoped to reveal some of the major differences in crustal structure between these two margins and provide evidence for their modes of evolution during and after continental break- ...
... the Atlantic Ocean is a rifted margin, but facing the Indian Ocean is a 1200 km long margin offset. With this study it is hoped to reveal some of the major differences in crustal structure between these two margins and provide evidence for their modes of evolution during and after continental break- ...
Geologic Map of the Phoenix Mountains, Central Arizona
... of metamorphosed rhyolite tuff and felsic volcaniclastic rocks trends northward along both sides of 7th Street. Thunderbird Hills: The low-relief hills near Thunderbird Road and 7th Street are composed of Tertiary sediments that unconformably overlie greenstone on the west and Tertiary basalt on the ...
... of metamorphosed rhyolite tuff and felsic volcaniclastic rocks trends northward along both sides of 7th Street. Thunderbird Hills: The low-relief hills near Thunderbird Road and 7th Street are composed of Tertiary sediments that unconformably overlie greenstone on the west and Tertiary basalt on the ...
EAST AFRICAN RIFT SYSTEM
... eruptive fissures, local concentration of high activity may show up as possible geothermal targets. 1. INTRODUCTION The East African Rift system extends from the Red Sea/Gulf of Aden to Malawi and it is seismically active beyond. The rift started in the north in early Tertiary and propagated south w ...
... eruptive fissures, local concentration of high activity may show up as possible geothermal targets. 1. INTRODUCTION The East African Rift system extends from the Red Sea/Gulf of Aden to Malawi and it is seismically active beyond. The rift started in the north in early Tertiary and propagated south w ...
Structure and geological evolution of the bedrock of
... central, NW -SE trending area of sandstone, and a psammitic migmatite belt in the northeast. The migmatite belts formed during the Svecofennian orogeny, 1900-1800 Ma ago (Palaeoproterozoic). The sandstone area is the remnant of an alluvial basin, preserved now in a NW -SE trending graben, bounded on ...
... central, NW -SE trending area of sandstone, and a psammitic migmatite belt in the northeast. The migmatite belts formed during the Svecofennian orogeny, 1900-1800 Ma ago (Palaeoproterozoic). The sandstone area is the remnant of an alluvial basin, preserved now in a NW -SE trending graben, bounded on ...
pdf file - University of Victoria
... et al. (2013) and Arcay et al. (2006) discuss how the fluid conmost recent widespread igneous activity, crustal deformation, tent strongly reduces the viscosity of the mantle. In any case, and metamorphism) greater than about 500 Ma (most of the independent of the causes, the evidence for high tempe ...
... et al. (2013) and Arcay et al. (2006) discuss how the fluid conmost recent widespread igneous activity, crustal deformation, tent strongly reduces the viscosity of the mantle. In any case, and metamorphism) greater than about 500 Ma (most of the independent of the causes, the evidence for high tempe ...
On the structure and mechanical behaviour of the - Perso-sdt
... plate rheology, which allow us to model of external tectonic forces acting on the plates and determination of the Moho geometry. We show that the clearest expression of extensional processes occurs in the central part of the rift, which exhibits the highest crustal thinning. It evolves southwards to ...
... plate rheology, which allow us to model of external tectonic forces acting on the plates and determination of the Moho geometry. We show that the clearest expression of extensional processes occurs in the central part of the rift, which exhibits the highest crustal thinning. It evolves southwards to ...
V. C. Summer Nuclear Station, Units 2 and 3 COL Application
... various types of gneisses, amphibolite, gabbroic and volcanic rock, and metasedimentary rock. All Grenville basement rock is metamorphosed to granulite or uppermost amphibolite facies (Reference 279). The calculated radiometric ages of these rocks generally range from 1,000 to 1,200 Ma (e.g., Refere ...
... various types of gneisses, amphibolite, gabbroic and volcanic rock, and metasedimentary rock. All Grenville basement rock is metamorphosed to granulite or uppermost amphibolite facies (Reference 279). The calculated radiometric ages of these rocks generally range from 1,000 to 1,200 Ma (e.g., Refere ...
WalkerJ_JGR_95(B13)21483 - KU ScholarWorks
... research, and such observations and samples are not available. Therefore we support our hypothesis by comparing the compositionof the Ulugh Muztagh samples to the expected composition of liquids producedby partial ...
... research, and such observations and samples are not available. Therefore we support our hypothesis by comparing the compositionof the Ulugh Muztagh samples to the expected composition of liquids producedby partial ...
Depositional History and Tectonic Regimes within and in
... Neoproterozoic and Phanerozoic sedimentary rocks in Finland and their depositional history The report also summarizes the tectonic and magmatic events within and in the margins of the Fennoscandian Shield during the last 1200 - 1300 million years. Mesoproterozoic (Middle Riphean) and Neoproterozoic ...
... Neoproterozoic and Phanerozoic sedimentary rocks in Finland and their depositional history The report also summarizes the tectonic and magmatic events within and in the margins of the Fennoscandian Shield during the last 1200 - 1300 million years. Mesoproterozoic (Middle Riphean) and Neoproterozoic ...
A numerical investigation of continental collision styles
... sensitivity of these collision styles to driving velocity, crustal and lithospheric temperature, continental rheology and the initial density difference between the oceanic lithosphere and the asthenosphere. We find that these parameters influence the collision system, but that driving velocity, rhe ...
... sensitivity of these collision styles to driving velocity, crustal and lithospheric temperature, continental rheology and the initial density difference between the oceanic lithosphere and the asthenosphere. We find that these parameters influence the collision system, but that driving velocity, rhe ...
Papers presented to the conference on Plateau Uplift, Mode and
... southern Brasil. From the northern part of Rio Grande do Sul state, the eastern edge of the lava plateau and its continuation in the older crystalline rocks of the Serra do Mar of the Ponta Grossa Arch (state of Parana) and northeastward into the states of sao Paulo and Rio de Janeiro constitute a h ...
... southern Brasil. From the northern part of Rio Grande do Sul state, the eastern edge of the lava plateau and its continuation in the older crystalline rocks of the Serra do Mar of the Ponta Grossa Arch (state of Parana) and northeastward into the states of sao Paulo and Rio de Janeiro constitute a h ...
Stratigraphic and structural evolution of the Blue Nile Basin
... Field and remote sensing studies have been focused on four accessible key areas along the Gorge of the Nile (Figure 2) that expose representative Mesozoic and Cenozoic stratigraphic successions and allow for examination of various structural styles and orientations (areas 1, 2, 3 and 4 on Figure 2). ...
... Field and remote sensing studies have been focused on four accessible key areas along the Gorge of the Nile (Figure 2) that expose representative Mesozoic and Cenozoic stratigraphic successions and allow for examination of various structural styles and orientations (areas 1, 2, 3 and 4 on Figure 2). ...
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... larger and more elongated than at present. It was probably controlled by ENE trending faults. The thrusting of the Tarim plate under the southern Tien Shan results in the shortening of the upper crust at rates of <1015 mm/yr, whereas India moves northward at 50 mm/yr (Abdrakhmatov et al. 2001). A pa ...
... larger and more elongated than at present. It was probably controlled by ENE trending faults. The thrusting of the Tarim plate under the southern Tien Shan results in the shortening of the upper crust at rates of <1015 mm/yr, whereas India moves northward at 50 mm/yr (Abdrakhmatov et al. 2001). A pa ...
Recycling of the continental crust | SpringerLink
... Abstract--In order to understand the evolution of the crust-mantle system, it is important to recognize the role played by the recycling of continental crust. Crustal recycling can be considered as two fundamentally distinct processes: 1) intracrustal recycling and 2) crust-mantle recycling. Intracr ...
... Abstract--In order to understand the evolution of the crust-mantle system, it is important to recognize the role played by the recycling of continental crust. Crustal recycling can be considered as two fundamentally distinct processes: 1) intracrustal recycling and 2) crust-mantle recycling. Intracr ...
Carbonaceous schists of the Main Central Thrust zone as a source
... Carbonaceous materials in metasedimentary rocks recrystallize to form graphite structure with increasing diagenesis and metamorphism and reaches to the fully ordered graphite. This recrystallization is called graphitization and can be examined by the X-ray powder Diffractometer. X-ray diffraction an ...
... Carbonaceous materials in metasedimentary rocks recrystallize to form graphite structure with increasing diagenesis and metamorphism and reaches to the fully ordered graphite. This recrystallization is called graphitization and can be examined by the X-ray powder Diffractometer. X-ray diffraction an ...
Weakness of the lower continental crust: a condition for
... the lower crust and sub-crustal lithosphere, escape tectonics (i.e., lateral crustal flow), and crustal uplift. We combine calculations of lithospheric viscosity–depth curves with geologic observations and seismic images of the deep crust to infer the mechanisms controlling these processes. The basi ...
... the lower crust and sub-crustal lithosphere, escape tectonics (i.e., lateral crustal flow), and crustal uplift. We combine calculations of lithospheric viscosity–depth curves with geologic observations and seismic images of the deep crust to infer the mechanisms controlling these processes. The basi ...
Oxygen 18oxygen 16 and DH studies of plutonic granitic and
... between the North American plate and terrane I, which was accretedduring the Late Jurassic,and the Coast Plutonic Belt between terrane I and terrane II, which was accreted during the Cretaceous. Note in this model that the suggestedaccretion period is the main period of plutonism. However, for these ...
... between the North American plate and terrane I, which was accretedduring the Late Jurassic,and the Coast Plutonic Belt between terrane I and terrane II, which was accreted during the Cretaceous. Note in this model that the suggestedaccretion period is the main period of plutonism. However, for these ...
Chapter 8
... Joint Systems – Paired joint sets that form at acute angles and are thus shear fractures. Difficult to make certain that the acute joints formed at the same time If you can prove they are conjugate then σ1 bisects the acute angle ...
... Joint Systems – Paired joint sets that form at acute angles and are thus shear fractures. Difficult to make certain that the acute joints formed at the same time If you can prove they are conjugate then σ1 bisects the acute angle ...
Geology of Southwestern Alaska (3.0MB, PDF)
... tains that are discussed in this chapter include parts of the Nixon Fork , Dillinger , and Mystic terranes, which Silberling and others (this volume) and Jones and Silberling (1979) originally defined as discrete , fault-bounded tectonostratigraphic terranes. Although these terranes have distinctive ...
... tains that are discussed in this chapter include parts of the Nixon Fork , Dillinger , and Mystic terranes, which Silberling and others (this volume) and Jones and Silberling (1979) originally defined as discrete , fault-bounded tectonostratigraphic terranes. Although these terranes have distinctive ...
47. the ocean/continent transition beneath the iberia abyssal plain
... Lusitanian Basin and its probable north-northwest offshore continuation, the Interior Basin, which separates Galicia Bank from mainland Spain (Murillas et al., 1990). The Lusitanian Basin formed by the extensional reactivation of Hercynian basement faults beginning in the Late Triassic (Montenat et ...
... Lusitanian Basin and its probable north-northwest offshore continuation, the Interior Basin, which separates Galicia Bank from mainland Spain (Murillas et al., 1990). The Lusitanian Basin formed by the extensional reactivation of Hercynian basement faults beginning in the Late Triassic (Montenat et ...
The origin and evolution of the Earth`s continental crust
... Archaean sediments. This stands in contrast to the very uniform post-Archaean sedimentary REE patterns. Both very steep and flat patterns are locally abundant. The flat patterns are derived from basaltic precursors to first-cycle sediments. The steep patterns occur in first-cycle sediments derived d ...
... Archaean sediments. This stands in contrast to the very uniform post-Archaean sedimentary REE patterns. Both very steep and flat patterns are locally abundant. The flat patterns are derived from basaltic precursors to first-cycle sediments. The steep patterns occur in first-cycle sediments derived d ...
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.