![Metamorphic reworking of a high pressure–low temperature](http://s1.studyres.com/store/data/002380407_1-e2d5e6a4f84baf9ecf3aed4a62370814-300x300.png)
Metamorphic reworking of a high pressure–low temperature
... strongly overprinted by a lower pressure assemblage and, along with associated HP/LT rocks, give much younger 40Ar/39Ar ages of 88–55 Ma indicating a later amphibolite facies metamorphic event. We propose therefore that all serpentinite hosted eclogites along the Motagua fault formed at essentially ...
... strongly overprinted by a lower pressure assemblage and, along with associated HP/LT rocks, give much younger 40Ar/39Ar ages of 88–55 Ma indicating a later amphibolite facies metamorphic event. We propose therefore that all serpentinite hosted eclogites along the Motagua fault formed at essentially ...
Paper
... Figure 7: Identification of BOS and FOS along bathymetric profile ARG-30-31B. First derivative (blue line) and second positive derivative (red line). 8- Discussion and Conclusion As it is seen in Figure 7, there is a maximum change in gradient associated with base of each terrace of the CDS. This f ...
... Figure 7: Identification of BOS and FOS along bathymetric profile ARG-30-31B. First derivative (blue line) and second positive derivative (red line). 8- Discussion and Conclusion As it is seen in Figure 7, there is a maximum change in gradient associated with base of each terrace of the CDS. This f ...
modern and ancient incompatible element-poor adakite
... fluids to the mantle source region. The Mocha Fracture Zone of the Nazca plate, which projects beneath the Quaternary arc at the latitude of NLV, may be responsible for the elevated slab-component of NLV magmas. Oceanic transform faults commonly host serpentinized peridotite bodies, which can libera ...
... fluids to the mantle source region. The Mocha Fracture Zone of the Nazca plate, which projects beneath the Quaternary arc at the latitude of NLV, may be responsible for the elevated slab-component of NLV magmas. Oceanic transform faults commonly host serpentinized peridotite bodies, which can libera ...
Space geodetic observation of deep basal subduction erosion in
... might be the landward retreat rate of the trench vt (Fig. 5), which is suggested to be s 3 km/Myr [23] from the ¢nal inundation age of the unconformity, paleo-trench depth of s 7 km, and continental slope of 5‡. Here we revise this value by assuming the subduction zone geometry similar to present: i ...
... might be the landward retreat rate of the trench vt (Fig. 5), which is suggested to be s 3 km/Myr [23] from the ¢nal inundation age of the unconformity, paleo-trench depth of s 7 km, and continental slope of 5‡. Here we revise this value by assuming the subduction zone geometry similar to present: i ...
The Agulhas – Karoo Geoscience Transect: from a sheared margin
... accumulate or accrete when continental margins are active. Today, oceanic plateaux, which can be extinct island arcs, extinct spreading ridges, seamounts, or disrupted fragments of continental crust, are passive features that are embedded within the oceanic lithosphere. When large enough, they resis ...
... accumulate or accrete when continental margins are active. Today, oceanic plateaux, which can be extinct island arcs, extinct spreading ridges, seamounts, or disrupted fragments of continental crust, are passive features that are embedded within the oceanic lithosphere. When large enough, they resis ...
pdf-file - Art Periods
... The south-central Chilean subduction zone has witnessed some of the largest earthquakes in history, making this region particularly important for understanding plate coupling. Here we present the results of a local earthquake tomography study from a temporary local seismic network in the Villarrica ...
... The south-central Chilean subduction zone has witnessed some of the largest earthquakes in history, making this region particularly important for understanding plate coupling. Here we present the results of a local earthquake tomography study from a temporary local seismic network in the Villarrica ...
Simple Models of Diffuse Extension and the Pre
... The two model s dist:ussed above botb assume Înstantaneous extension. This ass umption makes the mathematical tTeatment much simpler by pro'liding simple and weil dcf incd initial conditions, but does not correspond 10 what is found in nature. The pre -seafloor spreading rifting his lory of continen ...
... The two model s dist:ussed above botb assume Înstantaneous extension. This ass umption makes the mathematical tTeatment much simpler by pro'liding simple and weil dcf incd initial conditions, but does not correspond 10 what is found in nature. The pre -seafloor spreading rifting his lory of continen ...
rea proposta para extenso da plataforma
... have been compiled using magnetic anomaly data [e.g., Sclater et al., 1981; Larson et al., 1985]. A digital version of the latter map was produced by Cazenave et al. [1988], at a grid interval of half a degree (approx. 55 km). Recent improvements in identifications of magnetic anomalies and plate ki ...
... have been compiled using magnetic anomaly data [e.g., Sclater et al., 1981; Larson et al., 1985]. A digital version of the latter map was produced by Cazenave et al. [1988], at a grid interval of half a degree (approx. 55 km). Recent improvements in identifications of magnetic anomalies and plate ki ...
Document
... interpreted the geochemistry of these basic igneous rocks in terms of an early rifting event followed by ocean floor spreading. However, there is no unequivocal evidence to suggest that these events occurred within a major ocean basin (i.e. the Iapetus Ocean). Consequently, the overall setting of th ...
... interpreted the geochemistry of these basic igneous rocks in terms of an early rifting event followed by ocean floor spreading. However, there is no unequivocal evidence to suggest that these events occurred within a major ocean basin (i.e. the Iapetus Ocean). Consequently, the overall setting of th ...
geochronology of proterozoic basement inliers from the colombian
... to ovoid, with dimensions between 50 and 150 µm. Their internal structure on CL images is characterized by very clear core-border patterns. Most cores show oscillatory zoning typical of magmatic zircons, while borders are usually diffuse and homogenous, typical of metamorphic overgrowth. Such typolo ...
... to ovoid, with dimensions between 50 and 150 µm. Their internal structure on CL images is characterized by very clear core-border patterns. Most cores show oscillatory zoning typical of magmatic zircons, while borders are usually diffuse and homogenous, typical of metamorphic overgrowth. Such typolo ...
Greater India Basin hypothesis and a two
... hundreds of kilometers wide until collision with Asia, Aitchison et al. (13, 28) demonstrated that the leading edge of Greater India would have passed the equator approximately 55 Ma ago, and suggested that the 55–50 Ma collision record (what is widely regarded as the Tibetan Himalaya–Asia collision ...
... hundreds of kilometers wide until collision with Asia, Aitchison et al. (13, 28) demonstrated that the leading edge of Greater India would have passed the equator approximately 55 Ma ago, and suggested that the 55–50 Ma collision record (what is widely regarded as the Tibetan Himalaya–Asia collision ...
Lower plate deformation at the Chile Triple Junction from the
... 4. Structure of the Ocean Floor in the CTJ Region 4.1. Bathymetry of the SCR North of the CTJ The SCR offshore southern Chile consists of spreading segments trending ~N160°, separated by a series of parallel fracture zones, from north to south: the Guamblin, Darwin, Taitao, and Tres Montes FZs (Figu ...
... 4. Structure of the Ocean Floor in the CTJ Region 4.1. Bathymetry of the SCR North of the CTJ The SCR offshore southern Chile consists of spreading segments trending ~N160°, separated by a series of parallel fracture zones, from north to south: the Guamblin, Darwin, Taitao, and Tres Montes FZs (Figu ...
Seismic reflection image of the Great Sumatra
... scarps at the seafloor and the geometry of the offsets associated with R1 and R2 at the top and base of the oceanic crust suggest that these deep crustal faults are not bending-related normal faults. Furthermore, seafloor mapping12 and seismological studies13 on the IndoAustralian plate indicate the ...
... scarps at the seafloor and the geometry of the offsets associated with R1 and R2 at the top and base of the oceanic crust suggest that these deep crustal faults are not bending-related normal faults. Furthermore, seafloor mapping12 and seismological studies13 on the IndoAustralian plate indicate the ...
ALKALINE PORPHYRY COPPER DEPOSITS AND - Rigeo
... and IOCG deposits are much more profound resulting from several different characteristics in: i) the geotectonic settings (subduction versus intracratonic); ii) the magma’s chemical composition (calk-alkaline or mildly alkaline versus MMM mantellic-metasomatic-magmas, Mitchell 1995) and migration dy ...
... and IOCG deposits are much more profound resulting from several different characteristics in: i) the geotectonic settings (subduction versus intracratonic); ii) the magma’s chemical composition (calk-alkaline or mildly alkaline versus MMM mantellic-metasomatic-magmas, Mitchell 1995) and migration dy ...
Episodic Tremor and Slip The Cascadia Subduction Zone
... the subduction fault, now referred to as the ETS slip zone. ETS is observed as very small, slow slips that occur far more frequently than the massive, sudden shifts that characterize a great earthquake. Across the locked zone, extending down to depths of 15 to 20 kilometres, plate convergence has be ...
... the subduction fault, now referred to as the ETS slip zone. ETS is observed as very small, slow slips that occur far more frequently than the massive, sudden shifts that characterize a great earthquake. Across the locked zone, extending down to depths of 15 to 20 kilometres, plate convergence has be ...
Morocco, 23-27 March 2015
... The Zenaga inlier, located south of the South Atlas Fault, represents the northern margin of the Palaeoproterozoic continental terrane (West African Craton) in the Southwest separated by the “Major Fault of the Anti-Atlas” which was considered as the northern limit of the West African Cration. This ...
... The Zenaga inlier, located south of the South Atlas Fault, represents the northern margin of the Palaeoproterozoic continental terrane (West African Craton) in the Southwest separated by the “Major Fault of the Anti-Atlas” which was considered as the northern limit of the West African Cration. This ...
Nazca slab retreat versus compressional deformation in the central
... tcctonic events occurred between longer periods of relative tectonic quiescence, they should correspond to ineatabiities of a steady-state tectonic regime. The state of stress within the Andean Cordikra should be controlled by the balance between boundary forces, that are due to convergence, and bod ...
... tcctonic events occurred between longer periods of relative tectonic quiescence, they should correspond to ineatabiities of a steady-state tectonic regime. The state of stress within the Andean Cordikra should be controlled by the balance between boundary forces, that are due to convergence, and bod ...
Proto-Oceanic Crust in the North and South Atlantic
... The mechanism of processes that rupture the continental crust, induce crustal extension, begin the initiation of crustal emplacement finally resulting in the drift phase of mid-ocean ridge formation are poorly understood. This is because of our limited knowledge of the deep structure of rifted margi ...
... The mechanism of processes that rupture the continental crust, induce crustal extension, begin the initiation of crustal emplacement finally resulting in the drift phase of mid-ocean ridge formation are poorly understood. This is because of our limited knowledge of the deep structure of rifted margi ...
Late Jurassic–Early Cretaceous intra
... into two blocks (the NE Japan and SW Japan blocks) by the Tanakura Tectonic Line (TTL) (Fig. 1a). The SW Japan Block is subdivided into the Inner and Outer zones by the Median Tectonic Line (MTL) (Fig. 1a). Both tectonic lines were originally a series of largescale left-lateral strike-slip fault sys ...
... into two blocks (the NE Japan and SW Japan blocks) by the Tanakura Tectonic Line (TTL) (Fig. 1a). The SW Japan Block is subdivided into the Inner and Outer zones by the Median Tectonic Line (MTL) (Fig. 1a). Both tectonic lines were originally a series of largescale left-lateral strike-slip fault sys ...
Kimberlites and the start of plate tectonics
... sidering the possibility that the increased abunPT is a unique style of silicate planet convec- dance of KBLs in the past 1 Ga reflects the mastion, whereby rigid shells of lithosphere slide sive injection of H2O and CO2 into the mantle over weaker mantle asthenosphere and sink to after PT and deep ...
... sidering the possibility that the increased abunPT is a unique style of silicate planet convec- dance of KBLs in the past 1 Ga reflects the mastion, whereby rigid shells of lithosphere slide sive injection of H2O and CO2 into the mantle over weaker mantle asthenosphere and sink to after PT and deep ...
Understanding the 3D Structure of the Gilmore Fault Zone Through
... This study aims to clarify the tectonic evolution of the Lachlan Orogen by modelling the subsurface morphology of the Gilmore Fault Zone (GFZ). The GFZ marks a distinct geophysical contrast between (high gravity, low magnetic intensity) high-grade metamorphic rocks found in the Wagga metamorphic bel ...
... This study aims to clarify the tectonic evolution of the Lachlan Orogen by modelling the subsurface morphology of the Gilmore Fault Zone (GFZ). The GFZ marks a distinct geophysical contrast between (high gravity, low magnetic intensity) high-grade metamorphic rocks found in the Wagga metamorphic bel ...
Structural interpretation of Ceuta field, lake Maracaibo, Venezuela
... This interpretation, achieved in an interactive workstation, is centered around an area covered by a 3D seismic survey acquiredovermostoftheCeutaField,locatedinthe Maracaibo Basin, whichis situated between two Andean chains, on the northern edge of the South American Plate. GEOLOGICAL SETTING The st ...
... This interpretation, achieved in an interactive workstation, is centered around an area covered by a 3D seismic survey acquiredovermostoftheCeutaField,locatedinthe Maracaibo Basin, whichis situated between two Andean chains, on the northern edge of the South American Plate. GEOLOGICAL SETTING The st ...
12.710, Spring 2014, Problem Set 5, Isostacy Isostacy is the concept
... Consider the problem of oceanic-lithosphere subsidence. Suppose we observe that the depth below sea level of the spreading ridge axis is 2.5 km, and the depth of the sea floor away from the ridge axis above 50-million year-old lithosphere is 4.0 km. We want to estimate the thickness of the 50 m.y. o ...
... Consider the problem of oceanic-lithosphere subsidence. Suppose we observe that the depth below sea level of the spreading ridge axis is 2.5 km, and the depth of the sea floor away from the ridge axis above 50-million year-old lithosphere is 4.0 km. We want to estimate the thickness of the 50 m.y. o ...
The Hindu Kush Seismic Zone as a Paradigm
... mineral assemblages and PT conditions require that they were subducted to depths of 90–130 km (27–40 kbar) and then brought back to the surface, still retaining evidence of their UHP formation. The geological record shows that continental-derived UHP rocks can be formed by subduction of thinned cont ...
... mineral assemblages and PT conditions require that they were subducted to depths of 90–130 km (27–40 kbar) and then brought back to the surface, still retaining evidence of their UHP formation. The geological record shows that continental-derived UHP rocks can be formed by subduction of thinned cont ...
lecture7_tomo
... The processes of upwelling at the ridges are very different from the “hot plumes” in the earth’s mantle. Plumes are generally narrow, active structures that come from the “abyss” (English: relatively primitive mantle), but the ridge process is very shallow and are passive features due to decompressi ...
... The processes of upwelling at the ridges are very different from the “hot plumes” in the earth’s mantle. Plumes are generally narrow, active structures that come from the “abyss” (English: relatively primitive mantle), but the ridge process is very shallow and are passive features due to decompressi ...