Zircon Behaviour in Deeply Subducted Rocks
... the study of HP rocks (Gebauer 1996; Gebauer et al. 1997), there has been an explosion of ion microprobe U–Pb analysis to date zircon growth zones in subduction-related rocks. In dating HP rocks that have experienced temperatures above 650°C, the use of zircon is particularly important because the U ...
... the study of HP rocks (Gebauer 1996; Gebauer et al. 1997), there has been an explosion of ion microprobe U–Pb analysis to date zircon growth zones in subduction-related rocks. In dating HP rocks that have experienced temperatures above 650°C, the use of zircon is particularly important because the U ...
USGS Professional Paper 1697 - Alaska Resources Library and
... series of continental-margin arcs and companion subduction-zone assemblages around the CircumNorth Pacific; (2) continuation of opening of major sedimentary basins behind major arcs; (3) in the eastern part of the Circum-North Pacific, dextral transpression between the Pacific ocean plate and the pr ...
... series of continental-margin arcs and companion subduction-zone assemblages around the CircumNorth Pacific; (2) continuation of opening of major sedimentary basins behind major arcs; (3) in the eastern part of the Circum-North Pacific, dextral transpression between the Pacific ocean plate and the pr ...
Tectonostratigraphic Terranes and Tectonic Evolution of Mexico
... Sonora Megashear and Late Cretaceous-Paleogene northward displacement of Baja California. Next, we review constraints imposed by plate motion models on the tectonic evolution of the region. Finally, we present a reconstruction of the tectonic evolution of the region that, while certainly not a uniqu ...
... Sonora Megashear and Late Cretaceous-Paleogene northward displacement of Baja California. Next, we review constraints imposed by plate motion models on the tectonic evolution of the region. Finally, we present a reconstruction of the tectonic evolution of the region that, while certainly not a uniqu ...
Mantle-derived magmas and magmatic Ni-Cu-(PGE) deposits
... Melting can occur via a variety of different physical processes, including: 1) equilibrium (batch) melting in which the melt remains in equilibrium with the source, resulting in only moderate fractionation of highly from moderately incompatible elements; 2) fractional melting, in which the melt is c ...
... Melting can occur via a variety of different physical processes, including: 1) equilibrium (batch) melting in which the melt remains in equilibrium with the source, resulting in only moderate fractionation of highly from moderately incompatible elements; 2) fractional melting, in which the melt is c ...
Rudnick and Lee.fm - Cin
... presence of fertile, hot peridotite xenoliths that erupted from the High Sierra in the Pliocene, which have Os isotopic compositions indistinguishable from convecting upper mantle. This later thinning event may be related to Basin and Range extension. Studies of mantle xenoliths from the Mojavia ter ...
... presence of fertile, hot peridotite xenoliths that erupted from the High Sierra in the Pliocene, which have Os isotopic compositions indistinguishable from convecting upper mantle. This later thinning event may be related to Basin and Range extension. Studies of mantle xenoliths from the Mojavia ter ...
GEOLOGICAL SURVEY OF FINLAND Special Paper 48 2008 GTK
... The zircon TIMS U-Pb and Nd-Sm mineral isochron ages were processed at GTK and the secondary ion microprobe (SHRIMP) zircon UPb isotopic data were measured at VSEGEI, St. Petersburg. The geology and mineral occurrences are described in four volumes of Map Explanations totalling about 1400 pages, pre ...
... The zircon TIMS U-Pb and Nd-Sm mineral isochron ages were processed at GTK and the secondary ion microprobe (SHRIMP) zircon UPb isotopic data were measured at VSEGEI, St. Petersburg. The geology and mineral occurrences are described in four volumes of Map Explanations totalling about 1400 pages, pre ...
Bedrock Geology of the High Peaks Region, Marcy Massif
... be a correlation between An content of plagioclase and age of crystallization; the older the anorthosite, the higher the An content. Anorthosites of the Nain Province are largely ;unmetamorphosed and commonly contain troctolite members or olivine, in addition to having higher An contents, whereas yo ...
... be a correlation between An content of plagioclase and age of crystallization; the older the anorthosite, the higher the An content. Anorthosites of the Nain Province are largely ;unmetamorphosed and commonly contain troctolite members or olivine, in addition to having higher An contents, whereas yo ...
Thrust-top basin formation along a suture
... ian to early Maastrichtian timing of this possible marine influence is within the range of the Bearpaw transgressive event of the Cordilleran foreland basin and allows for regional stratigraphic correlation of the Cantwell basin with other sedimentary basins in northwestern North America. (3) Struct ...
... ian to early Maastrichtian timing of this possible marine influence is within the range of the Bearpaw transgressive event of the Cordilleran foreland basin and allows for regional stratigraphic correlation of the Cantwell basin with other sedimentary basins in northwestern North America. (3) Struct ...
CHAPTER 2 GEOLOGIC INVESTIGATIONS IN WESTERN SAUDI
... French geologist, Roman Karpoff, was active in the western and central parts of Saudi Arabia between 1955 and 1960. His primary goal was the study of water resources, but he published important papers (in French) on the Precambrian basement rocks on western Saudi Arabia. His article of 1957 was the ...
... French geologist, Roman Karpoff, was active in the western and central parts of Saudi Arabia between 1955 and 1960. His primary goal was the study of water resources, but he published important papers (in French) on the Precambrian basement rocks on western Saudi Arabia. His article of 1957 was the ...
Petrology, mineralogy, and origin of the Feragen ultramafic body
... cross-cutting chromitite veins occur and some bands bifurcate (Fig. 3). These smaller veins have variable orientations, but most are parallel or subparallel to larger NE- and NNW- trending joints and faults along which serpentinisation is often locally more intense. Serpentine and chlorite are alway ...
... cross-cutting chromitite veins occur and some bands bifurcate (Fig. 3). These smaller veins have variable orientations, but most are parallel or subparallel to larger NE- and NNW- trending joints and faults along which serpentinisation is often locally more intense. Serpentine and chlorite are alway ...
Evolution of Metamorphic Belts - CiteSeerX
... studied by Barrow (1893, 1912), Tilley (1925), Harker (1932), Wiseman (1934), Snelling (1957), Chinner (I960), and others. The facies series of this type is composed of the greenschist, epidote-amphibolite, and amphibolite facies, in order of increasing temperature. In this type, almandine garnet oc ...
... studied by Barrow (1893, 1912), Tilley (1925), Harker (1932), Wiseman (1934), Snelling (1957), Chinner (I960), and others. The facies series of this type is composed of the greenschist, epidote-amphibolite, and amphibolite facies, in order of increasing temperature. In this type, almandine garnet oc ...
LITHOGEOCHEMISTRY OF ULTRAMAFIC, GABBROIC AND
... FOR PETROGENESIS AND MINERAL POTENTIAL T.S. van Nostrand Regional Geology Section ...
... FOR PETROGENESIS AND MINERAL POTENTIAL T.S. van Nostrand Regional Geology Section ...
Ultrahigh-pressure metamorphism: tracing continental crust into the
... More and more evidence is being discovered in Phanerozoic collision belts of the burial of crustal rocks to previously unsuspected (and ever increasing) depths, presently on the order of 150^200 km, and of exhumation from such depths. This extends by almost one order of magnitude the depth classical ...
... More and more evidence is being discovered in Phanerozoic collision belts of the burial of crustal rocks to previously unsuspected (and ever increasing) depths, presently on the order of 150^200 km, and of exhumation from such depths. This extends by almost one order of magnitude the depth classical ...
thesis
... The Seiland Igneous Province (SIP) is situated in western Finnmark, Northern Norway. The SIP comprises a suite of mainly gabbroic plutons, with ultramafic, syenitic and felsic intrusions. The origin of the region has been interpreted in different ways and several tectonic models have been proposed. ...
... The Seiland Igneous Province (SIP) is situated in western Finnmark, Northern Norway. The SIP comprises a suite of mainly gabbroic plutons, with ultramafic, syenitic and felsic intrusions. The origin of the region has been interpreted in different ways and several tectonic models have been proposed. ...
granites of the lachlan fold belt
... the presence or absence of inherited zircon in the more mafic granites on a suite (less than ~ 68% SiO2). These groups correspond to those that evolved by restite fractionation sometimes followed by low-temperature fractional crystallisation, and those that evolved completely by fractional crystalli ...
... the presence or absence of inherited zircon in the more mafic granites on a suite (less than ~ 68% SiO2). These groups correspond to those that evolved by restite fractionation sometimes followed by low-temperature fractional crystallisation, and those that evolved completely by fractional crystalli ...
The Origin, Evolution and Present State of Subcontinental Lithosphere
... composition and evolution remains out of reach. The fact that the average continental crust is > 2.5 Ga whereas the oceanic crust is < 200 Ma tells us that the bulk continental crust (vs. the oceanic crust) is relatively permanent. The prevailing view holds that the subcontinental lithospheric mantl ...
... composition and evolution remains out of reach. The fact that the average continental crust is > 2.5 Ga whereas the oceanic crust is < 200 Ma tells us that the bulk continental crust (vs. the oceanic crust) is relatively permanent. The prevailing view holds that the subcontinental lithospheric mantl ...
Origins of the lower crustal reflectivity in the L¨utzow
... plex (Archean), the Rayner Complex (late-Proterozoic/earlyPaleozoic), the LHC (early-Paleozoic) and the YamatoBelgica Complex (early-Paleozoic) (Fig. 1). The Archean Napier Complex is known to be the oldest craton affected by ultra-high temperature (UHT) metamorphism (e.g., Black et al., 1987, Osana ...
... plex (Archean), the Rayner Complex (late-Proterozoic/earlyPaleozoic), the LHC (early-Paleozoic) and the YamatoBelgica Complex (early-Paleozoic) (Fig. 1). The Archean Napier Complex is known to be the oldest craton affected by ultra-high temperature (UHT) metamorphism (e.g., Black et al., 1987, Osana ...
PDF
... schist, talc schist, serpentinites, and metagabbros. This allochthon is characterized by NW-trending, upright folds, which deform the earlier sub-horizontal structures. The structurally lower nappe (southern allochthon) is dominated by NNE-trending folds which deform amphibolite facies schistose met ...
... schist, talc schist, serpentinites, and metagabbros. This allochthon is characterized by NW-trending, upright folds, which deform the earlier sub-horizontal structures. The structurally lower nappe (southern allochthon) is dominated by NNE-trending folds which deform amphibolite facies schistose met ...
The geology of the Váddás area, Troms
... The Váddás area in the North Norwegian Caledonides is underlain by the ¢orrovárri Nappe, the uppermost unit of the Kalak Nappe Complex, and the overlying Váddás Nappe representing the lowermost unit of the Reisa Nappe Complex. Both nappes form part of the Upper Allochthon. Only the upper part of the ...
... The Váddás area in the North Norwegian Caledonides is underlain by the ¢orrovárri Nappe, the uppermost unit of the Kalak Nappe Complex, and the overlying Váddás Nappe representing the lowermost unit of the Reisa Nappe Complex. Both nappes form part of the Upper Allochthon. Only the upper part of the ...
Carlin-Type Gold Deposits in Nevada: Critical Geologic
... Carlin-type Au deposits in Nevada have huge Au endowments that have made the state, and the United States, one of the leading Au producers in the world. Forty years of mining and numerous studies have provided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genet ...
... Carlin-type Au deposits in Nevada have huge Au endowments that have made the state, and the United States, one of the leading Au producers in the world. Forty years of mining and numerous studies have provided a detailed geologic picture of the deposits, yet a comprehensive and widely accepted genet ...
Lewisian, Torridonian and Moine Rocks of Scotland
... the Outer Hebrides and parts of Shetland (Figure 1.1). The Lewisian Gneiss Complex is exposed on the Outer Hebrides and also along the northwest coast of the mainland. It is composed of a variety of gneisses, including the oldest rocks in the British Isles, dated to just over 3000 Ma. Altogether, th ...
... the Outer Hebrides and parts of Shetland (Figure 1.1). The Lewisian Gneiss Complex is exposed on the Outer Hebrides and also along the northwest coast of the mainland. It is composed of a variety of gneisses, including the oldest rocks in the British Isles, dated to just over 3000 Ma. Altogether, th ...
mississippi valley-type lead-zinc deposits (mvt)
... MVT deposits account for approximately 25 percent of the world's lead and zinc resources, and they are dispersed throughout the world (Fig. 1). A large proportion of Pb and Zn production comes from several classic MVT districts located in the drainage basin of the Mississippi River in the central US ...
... MVT deposits account for approximately 25 percent of the world's lead and zinc resources, and they are dispersed throughout the world (Fig. 1). A large proportion of Pb and Zn production comes from several classic MVT districts located in the drainage basin of the Mississippi River in the central US ...
Rheological heterogeneity, mechanical anisotropy
... having a fabric coherent with the crustal fault kinematics and a thickness of ³200 km, much larger than the lithosphere thickness in the area (e.g., McNamara et al., 1994). We are therefore inclined to consider that major faults may crosscut the lithosphere and root into the sublithospheric mantle ( ...
... having a fabric coherent with the crustal fault kinematics and a thickness of ³200 km, much larger than the lithosphere thickness in the area (e.g., McNamara et al., 1994). We are therefore inclined to consider that major faults may crosscut the lithosphere and root into the sublithospheric mantle ( ...
Miocene and Early Pliocene Epithermal Gold
... Great Basin. Most deposits are spatially and temporally related to two magmatic assemblages: bimodal basaltrhyolite and western andesite. These magmatic assemblages are petrogenetic suites that reflect variations in tectonic environment of magma generation. The bimodal assemblage is a K-rich tholeii ...
... Great Basin. Most deposits are spatially and temporally related to two magmatic assemblages: bimodal basaltrhyolite and western andesite. These magmatic assemblages are petrogenetic suites that reflect variations in tectonic environment of magma generation. The bimodal assemblage is a K-rich tholeii ...
Formation and Exhumation of Ultrahigh
... 1995), triggering a range of specific tectonic processes such as volcanism and uplift. To many observers, this overall paradigm of rapid continental-margin subduction during the early stages of continental collision satisfies most of the geologic constraints teased from UHP occurrences. The dominanc ...
... 1995), triggering a range of specific tectonic processes such as volcanism and uplift. To many observers, this overall paradigm of rapid continental-margin subduction during the early stages of continental collision satisfies most of the geologic constraints teased from UHP occurrences. The dominanc ...
Yilgarn Craton
The Yilgarn Craton is a large craton that constitutes the bulk of the Western Australian land mass. It is bounded by a mixture of sedimentary basins and Proterozoic fold and thrust belts. Zircon grains in the Jack Hills, Narryer Terrane have been dated at ~4.27 Ga, with one detrital zircon dated as old as 4.4 Ga.