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... 20% of the area of all orogenic belts formed between 0.7 and 0.6 Ga. Table 4 of Artemieva (2006) splits late Precambrian time between two informal time periods, 750–550 Ma (11.7% of continental area) and 1.15–750 Ma (9.4%), so at least a tenth and as much as a fifth of crust is Neoproterozoic. In sp ...
... 20% of the area of all orogenic belts formed between 0.7 and 0.6 Ga. Table 4 of Artemieva (2006) splits late Precambrian time between two informal time periods, 750–550 Ma (11.7% of continental area) and 1.15–750 Ma (9.4%), so at least a tenth and as much as a fifth of crust is Neoproterozoic. In sp ...
Ascent of the ultrahigh-pressure Western Gneiss Region, Norway.
... Ca. 415–400 Ma ultrahigh-pressure (UHP) eclogites in the Western Gneiss Region of Norway occur in three discrete ~2500 km2 to >100 km2 antiformal domains separated by high-pressure rocks. Disparate eclogite ages suggest that the northern UHP domain and the two southern UHP domains are separate crust ...
... Ca. 415–400 Ma ultrahigh-pressure (UHP) eclogites in the Western Gneiss Region of Norway occur in three discrete ~2500 km2 to >100 km2 antiformal domains separated by high-pressure rocks. Disparate eclogite ages suggest that the northern UHP domain and the two southern UHP domains are separate crust ...
Georgian Bay Geological Synthesis, Grenville Province: Explanatory
... are made up of subgroupings of consistently associated rock types known as gneiss associations. These components of the domains are not usually separated by structures interpreted as thrusts, and their assembly within the domains therefore predates thrust stacking of domains. Two features of the geo ...
... are made up of subgroupings of consistently associated rock types known as gneiss associations. These components of the domains are not usually separated by structures interpreted as thrusts, and their assembly within the domains therefore predates thrust stacking of domains. Two features of the geo ...
Nickel - British Geological Survey
... millerite. The best known deposits of this type are found in the Kambalda Dome, Western Australia. The average grade for extrusive ultramafic deposits is about 3.3% Ni, although in other deposits elsewhere in the Yilgarn Craton grades can be as high as 7.7% Ni. Laterite deposits In subtropical and t ...
... millerite. The best known deposits of this type are found in the Kambalda Dome, Western Australia. The average grade for extrusive ultramafic deposits is about 3.3% Ni, although in other deposits elsewhere in the Yilgarn Craton grades can be as high as 7.7% Ni. Laterite deposits In subtropical and t ...
Magma mixing, mingling and hybridisation at different
... material. The margins of intrusive features and edges of individual mafic globules commonly show signs of hybridisation as indicated by intermediate coloured rocks (Fig. 2D). Kialineq Intrusive Centre – The Kialineq Intrusive Centre is located c. 200 km north of Tasiilaq (Fig. 1) in an extremely rug ...
... material. The margins of intrusive features and edges of individual mafic globules commonly show signs of hybridisation as indicated by intermediate coloured rocks (Fig. 2D). Kialineq Intrusive Centre – The Kialineq Intrusive Centre is located c. 200 km north of Tasiilaq (Fig. 1) in an extremely rug ...
Tectonic Setting and Regional Geology of the KSZ
... This study integrates petrological, structural, geochemical, geochronological and isotopic investigations of the geodynamic evolution of the Neoproterozoic Keraf Shear Zone (KSZ) in NE Sudan. It is a ~500 km long, thrust-bounded and wedge-shaped belt, that is narrower (∼30 km) in the S and wider (∼1 ...
... This study integrates petrological, structural, geochemical, geochronological and isotopic investigations of the geodynamic evolution of the Neoproterozoic Keraf Shear Zone (KSZ) in NE Sudan. It is a ~500 km long, thrust-bounded and wedge-shaped belt, that is narrower (∼30 km) in the S and wider (∼1 ...
The Guerrero Composite Terrane of western Mexico
... megashear (Anderson and Silver, 1979, 2005; Stewart et al., 1990). The Cortes Terrane is interpreted as an autochthonous terrane to North America, which probably evolved at the margin of the Caborca Terrane (Stewart et al., 1990). It is made up of a thick succession of Paleozoic deep-marine turbidit ...
... megashear (Anderson and Silver, 1979, 2005; Stewart et al., 1990). The Cortes Terrane is interpreted as an autochthonous terrane to North America, which probably evolved at the margin of the Caborca Terrane (Stewart et al., 1990). It is made up of a thick succession of Paleozoic deep-marine turbidit ...
Continental Growth and Recycling in Convergent Orogens with
... about 390 Ma (Figure 8f). Structural thickening and amalgamation of the WLO and CLO led to cratonization of the inner Lachlan [2]. Outboard in the ELO, syn-deformational ca. 440–435 Ma magmatism and high-T/low-P metamorphic belts formed during intermittent east-directed thrusting and periods of exte ...
... about 390 Ma (Figure 8f). Structural thickening and amalgamation of the WLO and CLO led to cratonization of the inner Lachlan [2]. Outboard in the ELO, syn-deformational ca. 440–435 Ma magmatism and high-T/low-P metamorphic belts formed during intermittent east-directed thrusting and periods of exte ...
1.8 Billion Years of Detrital Zircon Recycling Calibrates a
... Cordillera of North America provide exceptional context to explore the dynamics of sediment erosion and redeposition over deep geologic time (Table 1; Figs 1 and 2). An integration of bedrock geology, crustal-scale seismology, and detrital zircon U-Pb geochronology identifies two overarching reservo ...
... Cordillera of North America provide exceptional context to explore the dynamics of sediment erosion and redeposition over deep geologic time (Table 1; Figs 1 and 2). An integration of bedrock geology, crustal-scale seismology, and detrital zircon U-Pb geochronology identifies two overarching reservo ...
Article
... Cordillera of North America provide exceptional context to explore the dynamics of sediment erosion and redeposition over deep geologic time (Table 1; Figs 1 and 2). An integration of bedrock geology, crustal-scale seismology, and detrital zircon U-Pb geochronology identifies two overarching reservo ...
... Cordillera of North America provide exceptional context to explore the dynamics of sediment erosion and redeposition over deep geologic time (Table 1; Figs 1 and 2). An integration of bedrock geology, crustal-scale seismology, and detrital zircon U-Pb geochronology identifies two overarching reservo ...
Baltica in the Cryogenian, 850–630 Ma
... passive margin deposition throughout the Cryogenian. In the northeast platformal and deeper-water basin deposits are preserved, whereas the eastern region was later affected by Paleozoic rifting and preserves only shelf deposits. The northeastern and eastern regions define Baltica’s Cryogenian north ...
... passive margin deposition throughout the Cryogenian. In the northeast platformal and deeper-water basin deposits are preserved, whereas the eastern region was later affected by Paleozoic rifting and preserves only shelf deposits. The northeastern and eastern regions define Baltica’s Cryogenian north ...
early evolution of the North American Cordillera Baltican and
... Caledonides (part of Arctic Alaska; Nilsen 1981; Moore et al. 1994), or a combination of these end-members and northern Laurentia (e.g. Arctic Alaska, Eastern Klamath, Northern Sierra and others; Dumoulin et al. 2002; Wright & Wyld 2006; Lindsley-Griffin et al. 2008; Fig. 1). Equally important, shar ...
... Caledonides (part of Arctic Alaska; Nilsen 1981; Moore et al. 1994), or a combination of these end-members and northern Laurentia (e.g. Arctic Alaska, Eastern Klamath, Northern Sierra and others; Dumoulin et al. 2002; Wright & Wyld 2006; Lindsley-Griffin et al. 2008; Fig. 1). Equally important, shar ...
bedrock geology of the piedmont of delaware and adjacent
... This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allow ...
... This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allow ...
9.2 Metallic mineral occurrences in the shield and deposit types
... Its rocks developed at convergent margins during a 300-million year period of crustal growth involving the subduction of juvenile oceanic crust, the formation of early-mid Neoproterozoic intraoceanic and continental-margin volcanic-magmatic arcs, the deposition of mid-late Neoproterozoic sedimentary ...
... Its rocks developed at convergent margins during a 300-million year period of crustal growth involving the subduction of juvenile oceanic crust, the formation of early-mid Neoproterozoic intraoceanic and continental-margin volcanic-magmatic arcs, the deposition of mid-late Neoproterozoic sedimentary ...
Rare earth element geochemistry of the Permo
... sediments. Fluctuations in the Ce anomaly may provide information regarding transgressive–regressive phases in terrestrially-derived near-shore marine sediments. During a regressive phase, eroded nearshore sediments may be enriched in Ce(OH)4 thus increasing the positive Ce anomaly in marine sedimen ...
... sediments. Fluctuations in the Ce anomaly may provide information regarding transgressive–regressive phases in terrestrially-derived near-shore marine sediments. During a regressive phase, eroded nearshore sediments may be enriched in Ce(OH)4 thus increasing the positive Ce anomaly in marine sedimen ...
- ResearchOnline@JCU
... clear progressive increase in metamorphic grade through the belt from the south and west to the northeast (Black, 1977; Yokoyama et al., 1986; Spandler et al., 2003). However, the apparent rapid increase in metamorphic grade is largely due to extensive disruption of the original sequence by exhumati ...
... clear progressive increase in metamorphic grade through the belt from the south and west to the northeast (Black, 1977; Yokoyama et al., 1986; Spandler et al., 2003). However, the apparent rapid increase in metamorphic grade is largely due to extensive disruption of the original sequence by exhumati ...
PDF
... ANS is a collage of Neoproterozoic juvenile arcs, younger sedimentary and volcanic basins, voluminous granitoid intrusions, and enclaves of pre-Neoproterozoic crust that crop out in the western Arabian Plate and the northeastern African Plate (Fig. 1) at the northern end of the EAO (Stern, 1994; Kus ...
... ANS is a collage of Neoproterozoic juvenile arcs, younger sedimentary and volcanic basins, voluminous granitoid intrusions, and enclaves of pre-Neoproterozoic crust that crop out in the western Arabian Plate and the northeastern African Plate (Fig. 1) at the northern end of the EAO (Stern, 1994; Kus ...
preview PDF only - California State University Stanislaus
... interpretation in which the Chortis block originates in the eastern Pacific Ocean and is ~700–800 km south of the truncated continental margin of southwestern Mexico during the Eocene (Keppie and Moran-Zenteno, 2005) (Fig. 1A). In this model, Chortis is far-traveled (1100 km) from 45 to 0 Ma and exp ...
... interpretation in which the Chortis block originates in the eastern Pacific Ocean and is ~700–800 km south of the truncated continental margin of southwestern Mexico during the Eocene (Keppie and Moran-Zenteno, 2005) (Fig. 1A). In this model, Chortis is far-traveled (1100 km) from 45 to 0 Ma and exp ...
Iron Oxide Copper-Gold Deposits: Geology, Space
... Uncertainty also exists about the original tectonic settings of several major IOCG districts, and considerably more research is needed before it will be clear whether these deposits are linked by a single family of related genetic mechanisms or whether they can form in a range of fundamentally diffe ...
... Uncertainty also exists about the original tectonic settings of several major IOCG districts, and considerably more research is needed before it will be clear whether these deposits are linked by a single family of related genetic mechanisms or whether they can form in a range of fundamentally diffe ...
Geochemistry of the granitoid plutons of the Brookville terrane, Saint
... The Brookville terrane forms a fault-bounded region, underlain mainly by plutonic and high-grade metamorphic rocks, flanked on one side by a typical Avalonian terrane (Caledonia terrane), and separated from a typical Avalonian terrane (Mascarene terrane) on the other side by the Silurian Kingston Di ...
... The Brookville terrane forms a fault-bounded region, underlain mainly by plutonic and high-grade metamorphic rocks, flanked on one side by a typical Avalonian terrane (Caledonia terrane), and separated from a typical Avalonian terrane (Mascarene terrane) on the other side by the Silurian Kingston Di ...
ía Ip a ^'^á
... The presence of a metamorphic gradient, where grade increases towards the north, reflects a prograde low pressure regional metamorphism, initiated during the early deformational events, and ranges from the chlorite - muscovite zone in the south to the sillimanite - K-feldspar zone in the north. Loca ...
... The presence of a metamorphic gradient, where grade increases towards the north, reflects a prograde low pressure regional metamorphism, initiated during the early deformational events, and ranges from the chlorite - muscovite zone in the south to the sillimanite - K-feldspar zone in the north. Loca ...
(Neoproterozoic-Paleozoic) and plate reconstructions
... The sample collection includes volcanic as well as intrusive rocks of the paleo-island arc complex (Fig. 2b). One site (02ta-4) corresponds to an outcrop of plagiorhyodacites (sample A02-16), which has been dated by U-Pb method. The studied rocks are characterized by relatively low values of natural ...
... The sample collection includes volcanic as well as intrusive rocks of the paleo-island arc complex (Fig. 2b). One site (02ta-4) corresponds to an outcrop of plagiorhyodacites (sample A02-16), which has been dated by U-Pb method. The studied rocks are characterized by relatively low values of natural ...
Genesis of diamonds-the metamorphic point of view
... having resulted from the erosion of bedrock or "primary" sources 3.1. Placer in cratonic areas The oldest parts of continents are called cratons, and can be divided into two terranes: Archean-age archons, which are older than 2,500 million years, and Proterozoic-age protons, which are 1,600 -- 2,500 ...
... having resulted from the erosion of bedrock or "primary" sources 3.1. Placer in cratonic areas The oldest parts of continents are called cratons, and can be divided into two terranes: Archean-age archons, which are older than 2,500 million years, and Proterozoic-age protons, which are 1,600 -- 2,500 ...
Uppermost mantle structure of the North China Craton: Constraints
... The uppermost mantle is the key area for exchange of heat flux and material convection between the crust and lithospheric mantle. Spatial variations of lithospheric thinning and dynamic processes in the North China Craton could inevitably induce the velocity heterogeneity in the uppermost mantle. In ...
... The uppermost mantle is the key area for exchange of heat flux and material convection between the crust and lithospheric mantle. Spatial variations of lithospheric thinning and dynamic processes in the North China Craton could inevitably induce the velocity heterogeneity in the uppermost mantle. In ...
Pseudotachylytes, related fault rocks, asperities, and crustal structures in the
... the metamorphic belt are strongly deformed and retrogressively metamorphosed, giving rise to a N-S striking tonalite mylonite zone up to ca. 2 km wide (western-margin mylonite zone). The prominent foliations of the metamorphic rocks are steeply inclined to the east, except in the southern area of th ...
... the metamorphic belt are strongly deformed and retrogressively metamorphosed, giving rise to a N-S striking tonalite mylonite zone up to ca. 2 km wide (western-margin mylonite zone). The prominent foliations of the metamorphic rocks are steeply inclined to the east, except in the southern area of th ...
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.