Lower Continental Crust. - UCSB Earth Science
... OF CONTINENTAL CRUST Earth’s continental crust is widely believed to be andesitic to dacitic, with 57 to 66 wt% SiO2 (e.g., Rudnick & Gao 2003, 2014), distinct from mafic oceanic crust, with 48 to 52 wt% SiO2 , and from upper mantle residual peridotites, with <46 wt% SiO2 . Compared with oceanic crus ...
... OF CONTINENTAL CRUST Earth’s continental crust is widely believed to be andesitic to dacitic, with 57 to 66 wt% SiO2 (e.g., Rudnick & Gao 2003, 2014), distinct from mafic oceanic crust, with 48 to 52 wt% SiO2 , and from upper mantle residual peridotites, with <46 wt% SiO2 . Compared with oceanic crus ...
Geology of the Kimberley Region, Western Australia: The East
... by combined teams of Bureau of Mineral Resources and Geological Survey of Western Aus tralia geologists between 1962 and 1967: the results of the first three years' mapping—of the southeastern part of the Kimberiey region—are given in this Bulletin. Isotopic age deter minations were made on rocks ...
... by combined teams of Bureau of Mineral Resources and Geological Survey of Western Aus tralia geologists between 1962 and 1967: the results of the first three years' mapping—of the southeastern part of the Kimberiey region—are given in this Bulletin. Isotopic age deter minations were made on rocks ...
Bedrock Geology of the High Peaks Region, Marcy Massif
... modified from Emslie, 1974). The Adirondack Marcy massif may be considered as a southern extension of the Grenville Province across the narrow Frontenac axis. Plagioclase cumulates(or adcumulates)in anorthosites of the Nain Province(Fig. 3) intruded about 1450 M.Y. tend to be richer in An, 50's - 60 ...
... modified from Emslie, 1974). The Adirondack Marcy massif may be considered as a southern extension of the Grenville Province across the narrow Frontenac axis. Plagioclase cumulates(or adcumulates)in anorthosites of the Nain Province(Fig. 3) intruded about 1450 M.Y. tend to be richer in An, 50's - 60 ...
Adakitic Dacites Formed by Intracrustal Crystal Fractionation of
... contents. An origin by partial melting of high-pressure crustal sources seems unlikely from isotopic and trace element considerations. Mafic enclaves quenched into one of the dacites, on the other hand, constitute plausible parental magmas. Dacites and mafic enclaves share several characteristics su ...
... contents. An origin by partial melting of high-pressure crustal sources seems unlikely from isotopic and trace element considerations. Mafic enclaves quenched into one of the dacites, on the other hand, constitute plausible parental magmas. Dacites and mafic enclaves share several characteristics su ...
as PDF
... The ancestral Late Palaeozoic – Early Mesozoic Tien Shan belt was reactivated in the Late Mesozoic and a new mountain belt was built at this time along the inherited structural fabric. This is clearly illustrated by the foreland sediments of this Mesozoic Tien Shan range: Jurassic to Cretaceous sedi ...
... The ancestral Late Palaeozoic – Early Mesozoic Tien Shan belt was reactivated in the Late Mesozoic and a new mountain belt was built at this time along the inherited structural fabric. This is clearly illustrated by the foreland sediments of this Mesozoic Tien Shan range: Jurassic to Cretaceous sedi ...
nature ano evolution of the subcontinental mantle lithosphere below
... the Precambrian cratonic regions of Africa, suggests that the accretion of the lithospheric mande below southern South America was a relatively recent event, consistent with the Phanerozoic age of the crustal rocks in this region. The isotopic similarity of the Pali-Aike xenoliths with oceanic basal ...
... the Precambrian cratonic regions of Africa, suggests that the accretion of the lithospheric mande below southern South America was a relatively recent event, consistent with the Phanerozoic age of the crustal rocks in this region. The isotopic similarity of the Pali-Aike xenoliths with oceanic basal ...
PDF
... parallel belts: (1) Outer Zagros Ophiolitic Belt (OB) and (2) Inner Zagros Ophiolitic Belt (IB). These belts contain complete (if disrupted) ophiolites with well-preserved mantle and crustal sequences. Mantle sequences include tectonized harzburgite and rare ultramafic–mafic cumulates as well as iso ...
... parallel belts: (1) Outer Zagros Ophiolitic Belt (OB) and (2) Inner Zagros Ophiolitic Belt (IB). These belts contain complete (if disrupted) ophiolites with well-preserved mantle and crustal sequences. Mantle sequences include tectonized harzburgite and rare ultramafic–mafic cumulates as well as iso ...
Guidebook
... and spreading during this last period (Figure3). Rifting processes occur during the late Early Jurassic and the Middle Jurassic within the European Continental Margin (the Black Flysch-Ceahlău-Severin Rift). The opening of the Tethys and the distension of the mentioned rift, accompanied by the north ...
... and spreading during this last period (Figure3). Rifting processes occur during the late Early Jurassic and the Middle Jurassic within the European Continental Margin (the Black Flysch-Ceahlău-Severin Rift). The opening of the Tethys and the distension of the mentioned rift, accompanied by the north ...
Downdip landward limit of Cascadia great earthquake rupture
... [22] The most studied and one of the strongest constraints to the rupture zone is the definition of the locked zone on the thrust fault through “back-slip” modeling [e.g., Savage, 1983] of geodetic data (GPS, repeated leveling, tide gauges, etc.). This approach is based on the approximation that the ...
... [22] The most studied and one of the strongest constraints to the rupture zone is the definition of the locked zone on the thrust fault through “back-slip” modeling [e.g., Savage, 1983] of geodetic data (GPS, repeated leveling, tide gauges, etc.). This approach is based on the approximation that the ...
An enhanced image of the PamirHindu Kush
... The existence of intermediate-depth earthquakes beneath the Pamir^Hindu Kush region has long been recognized. The ¢rst published study of an earthquake in this region was the 1911 February 18 Pamir earthquake (Galitzin 1915), later also studied by Je¡reys 1923). In a historical aside, it is interest ...
... The existence of intermediate-depth earthquakes beneath the Pamir^Hindu Kush region has long been recognized. The ¢rst published study of an earthquake in this region was the 1911 February 18 Pamir earthquake (Galitzin 1915), later also studied by Je¡reys 1923). In a historical aside, it is interest ...
Fig. 1
... a b s t r a c t Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of ...
... a b s t r a c t Despite the importance of continental breakup in plate tectonics, precisely how extensional processes such as brittle faulting, ductile plate stretching, and magma intrusion evolve in space and time during the development of new ocean basins remains poorly understood. The rifting of ...
The East African rift system - Department of Earth and Planetary
... main tectonic features—with emphasis on the tension fractures—and volcanism in its relationships with the tectonics. The most characteristic features in the EARS are narrow elongate zones of thinned continental lithosphere related to asthenospheric intrusions in the upper mantle. This hidden part of ...
... main tectonic features—with emphasis on the tension fractures—and volcanism in its relationships with the tectonics. The most characteristic features in the EARS are narrow elongate zones of thinned continental lithosphere related to asthenospheric intrusions in the upper mantle. This hidden part of ...
Defining the Himalayan Main Central Thrust in Nepal
... Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada Abstract: An inverted metamorphic field gradient associated with a crustal-scale south-vergent thrust fault, the Main Central Thrust, has been recognized along the Himalaya for over 100 years. A maj ...
... Geological Sciences and Geological Engineering, Queen’s University, Kingston, Ontario K7L 3N6, Canada Abstract: An inverted metamorphic field gradient associated with a crustal-scale south-vergent thrust fault, the Main Central Thrust, has been recognized along the Himalaya for over 100 years. A maj ...
Peridotite and Metabasic Rocks of the Marianské Lázně
... plagioclase + sodic augite ± amphibole symplectite, garnet by plagioclase + amphibole ± sodic augite kelyphite, kyanite by spinel and plagioclase, which contains lamellar sapphirine and corundum, and rutile by titanite; locally, coronas of sodic augite + orthopyroxene + plagioclase + amphibole occur ...
... plagioclase + sodic augite ± amphibole symplectite, garnet by plagioclase + amphibole ± sodic augite kelyphite, kyanite by spinel and plagioclase, which contains lamellar sapphirine and corundum, and rutile by titanite; locally, coronas of sodic augite + orthopyroxene + plagioclase + amphibole occur ...
Download. - CHPM2030
... formulating a detailed concept on the application of the CHPM technology in Europe. With the investigation of the metallogenic provinces and geothermal conditions of Europe, we can outline the areas where the CHPM systems can potentially be developed. The study is structured in eight sections: In Se ...
... formulating a detailed concept on the application of the CHPM technology in Europe. With the investigation of the metallogenic provinces and geothermal conditions of Europe, we can outline the areas where the CHPM systems can potentially be developed. The study is structured in eight sections: In Se ...
EGS-relevant review of metallogenesis
... formulating a detailed concept on the application of the CHPM technology in Europe. With the investigation of the metallogenic provinces and geothermal conditions of Europe, we can outline the areas where the CHPM systems can potentially be developed. The study is structured in eight sections: In Se ...
... formulating a detailed concept on the application of the CHPM technology in Europe. With the investigation of the metallogenic provinces and geothermal conditions of Europe, we can outline the areas where the CHPM systems can potentially be developed. The study is structured in eight sections: In Se ...
Mantle structure and tectonic history of SE Asia
... the positive velocity anomaly can be traced well into the lower mantle to depths of c. 1500 km (Fukao et al., 1992; Puspito and Shimazaki, 1995; Widiyantoro and van der Hilst, 1997). This is not an artefact of tomographic methodology and we consider it to be lithosphere that was subducted before the ...
... the positive velocity anomaly can be traced well into the lower mantle to depths of c. 1500 km (Fukao et al., 1992; Puspito and Shimazaki, 1995; Widiyantoro and van der Hilst, 1997). This is not an artefact of tomographic methodology and we consider it to be lithosphere that was subducted before the ...
`emplacement` of an ophiolite?
... (Varne et al. 2000) or suboceanic mantle (Daczko et al. 2002), rather than a continental margin or a subduction-accretion complex. A metamorphic sole is not exposed. If such a sole were present, it would be beneath the present level of exposure. Igneous ages of the Macquarie Island ophiolite, determ ...
... (Varne et al. 2000) or suboceanic mantle (Daczko et al. 2002), rather than a continental margin or a subduction-accretion complex. A metamorphic sole is not exposed. If such a sole were present, it would be beneath the present level of exposure. Igneous ages of the Macquarie Island ophiolite, determ ...
Open-File Report 2005-1235
... Table 1. Description of the spatial databases prepared for the Northern Rocky Mountains compilation....... 6 Table 2. List and description of digital files developed for this report........................................................... 7 Table 3. Summary of the ArcInfo® feature attribute table ...
... Table 1. Description of the spatial databases prepared for the Northern Rocky Mountains compilation....... 6 Table 2. List and description of digital files developed for this report........................................................... 7 Table 3. Summary of the ArcInfo® feature attribute table ...
The origin of metamorphic core complexes and detachment faults
... through a progression of different metamorphic and deformational environments, producing a characteristic sequence of (overprinted) meso- and microstructures. The movement zone is folded as the result of the bowing upwards of the lower crust to form a broad basement culmination, as the result of iso ...
... through a progression of different metamorphic and deformational environments, producing a characteristic sequence of (overprinted) meso- and microstructures. The movement zone is folded as the result of the bowing upwards of the lower crust to form a broad basement culmination, as the result of iso ...
3.20 Trace Element and Isotopic Fluxes
... Whereas case studies and syntheses of the geochemistry of arc magmas abound (see Pearce and Peate, 1995; Elliott, 2003; Chapter 3.18; Figure 2a), the study of the geochemistry of slab metamorphic rocks (certain high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic suites) has lagged behind, li ...
... Whereas case studies and syntheses of the geochemistry of arc magmas abound (see Pearce and Peate, 1995; Elliott, 2003; Chapter 3.18; Figure 2a), the study of the geochemistry of slab metamorphic rocks (certain high-pressure (HP) and ultrahigh-pressure (UHP) metamorphic suites) has lagged behind, li ...
Towards a Creationist Explanation of Regional
... The metasedimentary sheaths surrounding stratiform sulfide orebodies have facilitated the study of regional metamorphic processes on a much smaller scale. Such orebodies were produced by hydrothermal waters disgorging both sulfides and a variety of other minerals and chemicals onto the sea-floor, where ...
... The metasedimentary sheaths surrounding stratiform sulfide orebodies have facilitated the study of regional metamorphic processes on a much smaller scale. Such orebodies were produced by hydrothermal waters disgorging both sulfides and a variety of other minerals and chemicals onto the sea-floor, where ...
Paleozoic–Mesozoic Porphyry Cu(Mo) and Mo(Cu) Deposits within
... are located within Western Pacific and Central Andes [7,9–12]. However, recent studies show that a number of porphyry Cu–Mo deposits have been formed in collisional zones or intracontinental tectonic settings in association with shoshonitic and high-K calc-alkaline magmas [13–16]. Examples include Y ...
... are located within Western Pacific and Central Andes [7,9–12]. However, recent studies show that a number of porphyry Cu–Mo deposits have been formed in collisional zones or intracontinental tectonic settings in association with shoshonitic and high-K calc-alkaline magmas [13–16]. Examples include Y ...
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.