Post-collision, Shoshonitic Volcanism on the Tibetan Plateau
... collision plate tectonics. Associated with the north by the Tarim basin, and to the south by the development of this orogen, and formed as a con- Himalaya (extending to the west in Pakistan as the sequence of the continuing indentation of India into Karakorum range). The structure of the plateau is ...
... collision plate tectonics. Associated with the north by the Tarim basin, and to the south by the development of this orogen, and formed as a con- Himalaya (extending to the west in Pakistan as the sequence of the continuing indentation of India into Karakorum range). The structure of the plateau is ...
Mildly peraluminous high-silica granites in the central part of the
... Precambrian crustal or enriched mantle contributions. The very low Sr values of all of these samples (-1 to -12, outside the main Oslo Rift magmatic array, Neumann et al., 1988; Anthony et al., 1989), point to a time integrated Rb-depleted crustal contaminant or an EM1 mantle component. The earlies ...
... Precambrian crustal or enriched mantle contributions. The very low Sr values of all of these samples (-1 to -12, outside the main Oslo Rift magmatic array, Neumann et al., 1988; Anthony et al., 1989), point to a time integrated Rb-depleted crustal contaminant or an EM1 mantle component. The earlies ...
The composition of the continental crust
... much discrepancy between the individual estimates. A larger difference in compositional estimates and genetic aspects exists between our present investigation and the widely used calculation of the lower and bulk crust composition by Taylor and McLennan (1985). The latter authors assume that the low ...
... much discrepancy between the individual estimates. A larger difference in compositional estimates and genetic aspects exists between our present investigation and the widely used calculation of the lower and bulk crust composition by Taylor and McLennan (1985). The latter authors assume that the low ...
UHP metamorphism in garnet peridotite, Cuaba unit, Rio San Juan
... Sediments and sedimentary rocks: Late Eocene to Oligocene clastic sedimentary rocks (Tm), Neogene limestone (Tl), Tertiary conglomerate (Tp), Quaternary alluvium and reef deposits (Q). ...
... Sediments and sedimentary rocks: Late Eocene to Oligocene clastic sedimentary rocks (Tm), Neogene limestone (Tl), Tertiary conglomerate (Tp), Quaternary alluvium and reef deposits (Q). ...
Behaviour of high field strength elements in subduction zones
... Amongst other hypotheses, the observed variations have been attributed to subduction processes involving rutile or amphibole [35 – 37]. Using the HFSE data for the Kamchatka/Aleutian rocks, we attempt (1) to assess differences in HFSE mobility during slab melting and dehydration and (2) to identify ...
... Amongst other hypotheses, the observed variations have been attributed to subduction processes involving rutile or amphibole [35 – 37]. Using the HFSE data for the Kamchatka/Aleutian rocks, we attempt (1) to assess differences in HFSE mobility during slab melting and dehydration and (2) to identify ...
The Great Basin Altiplano during the middle
... (1997) model states that the crust thinning was from 70 to 50 km by extensional unroofing between the Cretaceous and Eocene–Oligocene, whereas Constenius (1996) concluded that extensional basins formed from the middle Eocene to early Miocene. However, on the basis of his study of interbedded ash-flo ...
... (1997) model states that the crust thinning was from 70 to 50 km by extensional unroofing between the Cretaceous and Eocene–Oligocene, whereas Constenius (1996) concluded that extensional basins formed from the middle Eocene to early Miocene. However, on the basis of his study of interbedded ash-flo ...
Lithospheric evolution of the Andean fold–thrust belt, Bolivia, and
... 3.1.2. Long-duration, large-magnitude shortening The purpose of this paper is to present the other end member scenario for the evolution of the central Andean fold–thrust belt through the integration of several data sets (sedimentology/stratigraphy, structural geology, and geophysics) that are commo ...
... 3.1.2. Long-duration, large-magnitude shortening The purpose of this paper is to present the other end member scenario for the evolution of the central Andean fold–thrust belt through the integration of several data sets (sedimentology/stratigraphy, structural geology, and geophysics) that are commo ...
3.20 Trace Element and Isotopic Fluxes
... sedimentary equivalents (figure from Sadofsky and Bebout, 2003). Note that LOI correlates with SiO2/Al2O3 for the Catalina Schist (data from Bebout et al., 1999), Franciscan Complex Coast Ranges, California (Coastal, Central, and Eastern Belts; data from Sadofsky and Bebout, 2003), Diablo Range, Cali ...
... sedimentary equivalents (figure from Sadofsky and Bebout, 2003). Note that LOI correlates with SiO2/Al2O3 for the Catalina Schist (data from Bebout et al., 1999), Franciscan Complex Coast Ranges, California (Coastal, Central, and Eastern Belts; data from Sadofsky and Bebout, 2003), Diablo Range, Cali ...
Alignment between seafloor spreading directions and absolute plate
... 45° since 130 Ma, regardless of the choice of APM model, and less than 30° for some APM models (e.g., D2012; Figure 3a). Peaks and troughs in the results vary significantly between different APM models, because for the slower APM near the Atlantic spreading ridges (illustrated by the shorter bars in ...
... 45° since 130 Ma, regardless of the choice of APM model, and less than 30° for some APM models (e.g., D2012; Figure 3a). Peaks and troughs in the results vary significantly between different APM models, because for the slower APM near the Atlantic spreading ridges (illustrated by the shorter bars in ...
Seismic velocity structure of the rifted margin of the eastern Grand
... [10] North-south trending magnetic anomalies on the Grand Banks show continuity of basement structures with those of the Iberian peninsula, which reveals their common Paleozoic history [Haworth and Lefort, 1979]. It is believed that Mesozoic rifting in the Atlantic was facilitated by these Paleozoic ...
... [10] North-south trending magnetic anomalies on the Grand Banks show continuity of basement structures with those of the Iberian peninsula, which reveals their common Paleozoic history [Haworth and Lefort, 1979]. It is believed that Mesozoic rifting in the Atlantic was facilitated by these Paleozoic ...
Late Cretaceous–early Cenozoic tectonic evolution of
... prior to the 75 Ma or younger initiation of slip on the Nacimiento fault. Hence, formation of the schists was at least in part a separate phenomenon from the juxtaposition of the Salinian and Nacimiento blocks. On the other hand, both events appear to have been occurring simultaneously sometime betw ...
... prior to the 75 Ma or younger initiation of slip on the Nacimiento fault. Hence, formation of the schists was at least in part a separate phenomenon from the juxtaposition of the Salinian and Nacimiento blocks. On the other hand, both events appear to have been occurring simultaneously sometime betw ...
Density constraints on the formation of the continental Moho and crust
... rarely see eclogite in crustal rocks (Kennedy and Ito 1972). However, it has been pointed out that these phase diagrams based on linear extrapolations of high temperature experimental data may be in error (Herzberg 1978). Indeed, recent experimental and thermochemical work has shown that garnet gran ...
... rarely see eclogite in crustal rocks (Kennedy and Ito 1972). However, it has been pointed out that these phase diagrams based on linear extrapolations of high temperature experimental data may be in error (Herzberg 1978). Indeed, recent experimental and thermochemical work has shown that garnet gran ...
the massabesic gneiss complex, new hampshire
... compositions that are compatible with graywackes from continental arcs. The paragneiss also has strong lithologic, metamorphic, and isotopic similarities to the rocks of the Hope Valley zone of Connecticut Avalon, suggesting a possible Hope Valley— Massabesic correlation. At 625 Ma, the paragneiss ⑀ ...
... compositions that are compatible with graywackes from continental arcs. The paragneiss also has strong lithologic, metamorphic, and isotopic similarities to the rocks of the Hope Valley zone of Connecticut Avalon, suggesting a possible Hope Valley— Massabesic correlation. At 625 Ma, the paragneiss ⑀ ...
Geology of Greenland Survey Bulletin 177, 89-95
... recent trend towards a general acceptance of plate tectonics in the Archaean, unquestionable ocean floor sequences of Archaean age have not yet been identified (see p. 92), and it has not been settled if Archaean MORB had a composition similar to that of modern MORB. It is also still debated how imp ...
... recent trend towards a general acceptance of plate tectonics in the Archaean, unquestionable ocean floor sequences of Archaean age have not yet been identified (see p. 92), and it has not been settled if Archaean MORB had a composition similar to that of modern MORB. It is also still debated how imp ...
Evolution of the Earth as an andesite planet: water
... 40 vs. 6 km, respectively. The contrast in density is due to a difference in their average compositions; the continental crust is intermediate or andesitic, containing ~60 wt% SiO2, whereas the oceanic crust is mafic or basaltic, containing ~50 wt% SiO2 (e.g., Christensen and Mooney 1995; Kelemen 19 ...
... 40 vs. 6 km, respectively. The contrast in density is due to a difference in their average compositions; the continental crust is intermediate or andesitic, containing ~60 wt% SiO2, whereas the oceanic crust is mafic or basaltic, containing ~50 wt% SiO2 (e.g., Christensen and Mooney 1995; Kelemen 19 ...
Evolution of the Earth as an andesite planet: water, plate tectonics
... 40 vs. 6 km, respectively. The contrast in density is due to a difference in their average compositions; the continental crust is intermediate or andesitic, containing ~60 wt% SiO2, whereas the oceanic crust is mafic or basaltic, containing ~50 wt% SiO2 (e.g., Christensen and Mooney 1995; Kelemen 19 ...
... 40 vs. 6 km, respectively. The contrast in density is due to a difference in their average compositions; the continental crust is intermediate or andesitic, containing ~60 wt% SiO2, whereas the oceanic crust is mafic or basaltic, containing ~50 wt% SiO2 (e.g., Christensen and Mooney 1995; Kelemen 19 ...
Precambrian Research Geochemical and numerical constraints
... many challenges, and constructing uniform views from different disciplines on Archean plate tectonic models requires overcoming several geological, geochemical, and geophysical hurdles. First of all, time has taken its toll: Archean sites are now relatively sparse, and data are fragmented. This make ...
... many challenges, and constructing uniform views from different disciplines on Archean plate tectonic models requires overcoming several geological, geochemical, and geophysical hurdles. First of all, time has taken its toll: Archean sites are now relatively sparse, and data are fragmented. This make ...
Geology, 39
... Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen, Denmark ...
... Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen, Denmark ...
Relocation and assessment of seismicity in the Iran region
... period 1918–2004 have been relocated and reassessed, with special attention to focal depth, using an advanced technique for 1-D earthquake location. A careful review of starting depths, association of teleseismic depth phases, and the effects of reading errors on these phases are made and, when nece ...
... period 1918–2004 have been relocated and reassessed, with special attention to focal depth, using an advanced technique for 1-D earthquake location. A careful review of starting depths, association of teleseismic depth phases, and the effects of reading errors on these phases are made and, when nece ...
Variations in magmatic processes along the East Greenland
... to their distance from the Iceland plume. Holbrook et al. (2001) suggest that a modest margin-wide mantle thermal anomaly was present during break-up (∼56 Ma), which was exhausted by 43 Ma. Active upwelling is proposed for the proximal zone of the plume head, whereas the lateral emplacement of warm ...
... to their distance from the Iceland plume. Holbrook et al. (2001) suggest that a modest margin-wide mantle thermal anomaly was present during break-up (∼56 Ma), which was exhausted by 43 Ma. Active upwelling is proposed for the proximal zone of the plume head, whereas the lateral emplacement of warm ...
A Dynamic Model of Rifting Between Galicia Bank and Flemish Cap
... rifting, whereas deep seated weaknesses (mantle weaknesses) control the location where lithospheric necking develops and, hence, the location of eventual continental breakup. If these weaknesses are offset from one another, interior rift basins (controlled by the crustal weakness) often form landwar ...
... rifting, whereas deep seated weaknesses (mantle weaknesses) control the location where lithospheric necking develops and, hence, the location of eventual continental breakup. If these weaknesses are offset from one another, interior rift basins (controlled by the crustal weakness) often form landwar ...
The deep subsurface biosphere in igneous ocean crust: frontier
... plate divergence is diffuse, and the seafloor lacks a readily identifiable spreading center. In these and in other areas, the ocean crust is frequently faulted and delaminated almost as quickly as it is formed, exposing deeper crustal levels at the seafloor. This has important biogeochemical implicatio ...
... plate divergence is diffuse, and the seafloor lacks a readily identifiable spreading center. In these and in other areas, the ocean crust is frequently faulted and delaminated almost as quickly as it is formed, exposing deeper crustal levels at the seafloor. This has important biogeochemical implicatio ...
Deep structures and breakup along volcanic rifted margins: insights
... dome on the basin structure shows clearly that the dome predates the continental breakup. Based on the structural relationship and the results of the modelling, it is therefore concluded that the T Reflection does not necessarily originate from an anomalous Tertiary magmatic event related to the bre ...
... dome on the basin structure shows clearly that the dome predates the continental breakup. Based on the structural relationship and the results of the modelling, it is therefore concluded that the T Reflection does not necessarily originate from an anomalous Tertiary magmatic event related to the bre ...
Bebout Metamorphic chemical geodynamics of subduction zones
... Study of metamorphic suites directly representing the deep subduction of altered oceanic crust and sediments can help elucidate the geochemical evolution of the forearc-to-subarc slab–mantle interface, the nature of slab-derived fluids added to arc lava source regions, and the chemical changes in su ...
... Study of metamorphic suites directly representing the deep subduction of altered oceanic crust and sediments can help elucidate the geochemical evolution of the forearc-to-subarc slab–mantle interface, the nature of slab-derived fluids added to arc lava source regions, and the chemical changes in su ...
Metamorphic chemical geodynamics of subduction zones
... Study of metamorphic suites directly representing the deep subduction of altered oceanic crust and sediments can help elucidate the geochemical evolution of the forearc-to-subarc slab–mantle interface, the nature of slab-derived fluids added to arc lava source regions, and the chemical changes in su ...
... Study of metamorphic suites directly representing the deep subduction of altered oceanic crust and sediments can help elucidate the geochemical evolution of the forearc-to-subarc slab–mantle interface, the nature of slab-derived fluids added to arc lava source regions, and the chemical changes in su ...