The Asia–Kohistan–India Collision: Review and Discussion
... The Himalaya mountain range reaches the Hindu Kush and Karakoram in northern Pakistan where the Himalayan Orogen consists of three tectonic units (Fig. 10.1a and b): To the north, the late Cretaceous– Miocene Karakoram Batholith borders the Eurasian plate. To the south, deformed and metamorphosed sh ...
... The Himalaya mountain range reaches the Hindu Kush and Karakoram in northern Pakistan where the Himalayan Orogen consists of three tectonic units (Fig. 10.1a and b): To the north, the late Cretaceous– Miocene Karakoram Batholith borders the Eurasian plate. To the south, deformed and metamorphosed sh ...
Non-hotspot volcano chains from small
... deformation is characterized by much smaller wavelengths (50-500 km) than that, which are commonly expected for PLI (>1000 km); (2) plume head flattening is asymmetric below intra-plate boundaries, which leads to mechanical decoupling of crust from mantle lithosphere, and to localized faulting at t ...
... deformation is characterized by much smaller wavelengths (50-500 km) than that, which are commonly expected for PLI (>1000 km); (2) plume head flattening is asymmetric below intra-plate boundaries, which leads to mechanical decoupling of crust from mantle lithosphere, and to localized faulting at t ...
Extension Tectonics - Processes in Structural Geology and Tectonics
... So, surface thinning of “block” (upper crust) results in upward flow of “water” (lower crust). In MCCs, thinning by normal faulting results in exhumation of deeper detachment and basement rock. ...
... So, surface thinning of “block” (upper crust) results in upward flow of “water” (lower crust). In MCCs, thinning by normal faulting results in exhumation of deeper detachment and basement rock. ...
PDF (Chapter 8. Chemical Composition of the Mantle)
... and zosPb/204Pb.Midocean-ridge basalt (MORB) represents the most uniform and voluminous magma type and is an end member for LIL concentrations and isotopic ratios. This is logically taken as one of the components of the mantle. The MORB source has been depleted by removal of a component-Q-that must ...
... and zosPb/204Pb.Midocean-ridge basalt (MORB) represents the most uniform and voluminous magma type and is an end member for LIL concentrations and isotopic ratios. This is logically taken as one of the components of the mantle. The MORB source has been depleted by removal of a component-Q-that must ...
Flat versus steep subduction: Contrasting modes for the formation
... are not shown in Figure 1, but will appear during the evolution of the model (e.g., Figs. 3 and 4). In the numerical models, the medium-scale layering usually shares the same physical properties, with different colors used only for visualizing slab deformation and structural development. Detailed pr ...
... are not shown in Figure 1, but will appear during the evolution of the model (e.g., Figs. 3 and 4). In the numerical models, the medium-scale layering usually shares the same physical properties, with different colors used only for visualizing slab deformation and structural development. Detailed pr ...
vauchez_etal_rheology_1998_hal
... within the sublithospheric mantle; and (2) in most geodynamic environments, mechanical properties of the mantle govern the tectonic behaviour of the lithosphere. Lateral rheological heterogeneity of the continental lithosphere may result from various sources, with variations in geothermal gradient b ...
... within the sublithospheric mantle; and (2) in most geodynamic environments, mechanical properties of the mantle govern the tectonic behaviour of the lithosphere. Lateral rheological heterogeneity of the continental lithosphere may result from various sources, with variations in geothermal gradient b ...
Rheological heterogeneity, mechanical anisotropy and
... within the sublithospheric mantle; and (2) in most geodynamic environments, mechanical properties of the mantle govern the tectonic behaviour of the lithosphere. Lateral rheological heterogeneity of the continental lithosphere may result from various sources, with variations in geothermal gradient b ...
... within the sublithospheric mantle; and (2) in most geodynamic environments, mechanical properties of the mantle govern the tectonic behaviour of the lithosphere. Lateral rheological heterogeneity of the continental lithosphere may result from various sources, with variations in geothermal gradient b ...
On the origin of noble gases in mantle plumes
... and nucleogenic 21 Ne, it is commonly assumed that Loihi and Iceland are derived from pristine, undegassed portions of the mantle. In addition, the 40 Ar{40 K budget of the mantle tends to favour the existence of an undegassed reservoir in the lower mantle (All³egre et al. 1996). The understanding o ...
... and nucleogenic 21 Ne, it is commonly assumed that Loihi and Iceland are derived from pristine, undegassed portions of the mantle. In addition, the 40 Ar{40 K budget of the mantle tends to favour the existence of an undegassed reservoir in the lower mantle (All³egre et al. 1996). The understanding o ...
1. LEG 209 SUMMARY: PROCESSES IN A 20-KM
... ocean-ridge basalts. Clinopyroxene textures and compositions record such impregnation processes, and they are particularly well documented for Site 1274. Other Leg 209 gabbroic rocks formed from extensive crystallization of highly evolved melts, indicating that a substantial proportion of melt enter ...
... ocean-ridge basalts. Clinopyroxene textures and compositions record such impregnation processes, and they are particularly well documented for Site 1274. Other Leg 209 gabbroic rocks formed from extensive crystallization of highly evolved melts, indicating that a substantial proportion of melt enter ...
North Atlantic Igneous Province: A Review of
... earliest volcanic rocks are hyaloclastite breccias. After a significant Early Paleocene uplift, later volcanism was almost entirely sub-aerial (Dam et al., 1998). The volcanic rocks are divided into three formations (Gill et al., 1992): the lower formation mainly consists of picritic and other olivi ...
... earliest volcanic rocks are hyaloclastite breccias. After a significant Early Paleocene uplift, later volcanism was almost entirely sub-aerial (Dam et al., 1998). The volcanic rocks are divided into three formations (Gill et al., 1992): the lower formation mainly consists of picritic and other olivi ...
alps vs apennines - Dipartimento di Scienze della Terra
... asymmetry has been ascribed either to the more efficient slab pull in the western Pacific (FORSYTH & UYEDA, 1975) or to the westward drift of the lithosphere relative to the underlying mantle (DOGLIONI et alii, 1999b). The same different interpretations have been used for differentiating the Alps an ...
... asymmetry has been ascribed either to the more efficient slab pull in the western Pacific (FORSYTH & UYEDA, 1975) or to the westward drift of the lithosphere relative to the underlying mantle (DOGLIONI et alii, 1999b). The same different interpretations have been used for differentiating the Alps an ...
PDF (Chapter 3. The Crust and Upper Mantle)
... http://resolver.caltech.edu/CaltechBook:1989.001 Abstract: T he structure of the Earth's interior is fairly well known from seismology, and knowledge of the fine structure is improving continuously. Seismology not only provides the structure, it also provides information about the composition, cryst ...
... http://resolver.caltech.edu/CaltechBook:1989.001 Abstract: T he structure of the Earth's interior is fairly well known from seismology, and knowledge of the fine structure is improving continuously. Seismology not only provides the structure, it also provides information about the composition, cryst ...
Exhumation of (ultra-)high-pressure terranes: concepts
... Peak pressures are estimated using petrological reactions involving changes in molar volume. The determined pressures are commonly converted to depth by assuming that the pressure experienced is due only to the weight of the overburden (lithostatic pressure). However, recent field data and numerical ...
... Peak pressures are estimated using petrological reactions involving changes in molar volume. The determined pressures are commonly converted to depth by assuming that the pressure experienced is due only to the weight of the overburden (lithostatic pressure). However, recent field data and numerical ...
54. mesozoic-tertiary tectonic evolution of the easternmost
... is defined as that part of the Eastern Mediterranean Sea located east of the Aegean (east of 28°E longitude). At present, no one paleogeography is agreed upon by various workers (Figs. 2A−D, 3A–D). It is generally agreed that from Late Cretaceous to Holocene, the Eastern Mediterranean has been in a ...
... is defined as that part of the Eastern Mediterranean Sea located east of the Aegean (east of 28°E longitude). At present, no one paleogeography is agreed upon by various workers (Figs. 2A−D, 3A–D). It is generally agreed that from Late Cretaceous to Holocene, the Eastern Mediterranean has been in a ...
Magmatic constraints on geodynamic models of subduction in the
... basins served as a zone of weakened lithosphere into which the Alcapa and Tisza–Dacia microplates could indent during the Miocene collision. This area, prior to deformation, has been estimated to be up to 500 km across (Csontos, 1995). However, direct evidence for the existence of oceanic crust in t ...
... basins served as a zone of weakened lithosphere into which the Alcapa and Tisza–Dacia microplates could indent during the Miocene collision. This area, prior to deformation, has been estimated to be up to 500 km across (Csontos, 1995). However, direct evidence for the existence of oceanic crust in t ...
Geology - Archean Environment: The habitat of early life.
... a progressively degraded record with increasing age. However, it is likely that some Phanerozoic UHT granulite metamorphism rocks have not yet been exposed at Earth’s surface, leading to bias in the younger part of the record. Extrapolation back in time also raises questions about partial-to-complet ...
... a progressively degraded record with increasing age. However, it is likely that some Phanerozoic UHT granulite metamorphism rocks have not yet been exposed at Earth’s surface, leading to bias in the younger part of the record. Extrapolation back in time also raises questions about partial-to-complet ...
Secondary_4
... Sc6.1.4. Explain the importance of index fossils; Sc6.1.5. Identify and explain Steno’s Laws of superposition and original horizontality; Sc6.1.6. Describe the oldest and youngest formations based on geological cross-section; Sc6.1.7. Determine and identify the absolute age of objects; Sc6.1.8. Diff ...
... Sc6.1.4. Explain the importance of index fossils; Sc6.1.5. Identify and explain Steno’s Laws of superposition and original horizontality; Sc6.1.6. Describe the oldest and youngest formations based on geological cross-section; Sc6.1.7. Determine and identify the absolute age of objects; Sc6.1.8. Diff ...
A crustal model of the ultrahigh-pressure Dabie Shan orogenic belt
... north and south of the orogen are composed of 35-km-thick crust consisting of three layers (upper, middle, and lower crust) with average seismic velocities of 6.0 ⫾ 0.2 km/s, 6.5 ⫾ 0.1 km/s, and 6.8 ⫾ 0.1 km/s. The crust reaches a maximum thickness of 41.5 km beneath the northern margin of the oroge ...
... north and south of the orogen are composed of 35-km-thick crust consisting of three layers (upper, middle, and lower crust) with average seismic velocities of 6.0 ⫾ 0.2 km/s, 6.5 ⫾ 0.1 km/s, and 6.8 ⫾ 0.1 km/s. The crust reaches a maximum thickness of 41.5 km beneath the northern margin of the oroge ...
MAJOR-ELEMENT CHEMISTRY OF PLUTONIC ROCK SUITES
... Cenozoic plutonic suites generated at these plate boundaries. Compressional plutonic rock suites are characterized by intermediate unimodal frequency distributions of differentiation index and normative plagioclase, calc/alkali indexes in the range of 60--64, and distinctive patterns on AFM diagrams ...
... Cenozoic plutonic suites generated at these plate boundaries. Compressional plutonic rock suites are characterized by intermediate unimodal frequency distributions of differentiation index and normative plagioclase, calc/alkali indexes in the range of 60--64, and distinctive patterns on AFM diagrams ...
letters - Noble Gas Geochemistry Lab
... SCLM source for Spitsbergen lavas. Subsequent asthenospheric melting beneath the Gakkel ridge would then release the Rb and Ba, leading to the relative enrichments of these elements in the lavas of the WVZ. The data offer insight into the long-term history of the Gakkel asthenosphere. A Rb–Sr ‘pseud ...
... SCLM source for Spitsbergen lavas. Subsequent asthenospheric melting beneath the Gakkel ridge would then release the Rb and Ba, leading to the relative enrichments of these elements in the lavas of the WVZ. The data offer insight into the long-term history of the Gakkel asthenosphere. A Rb–Sr ‘pseud ...
magnetostratigraphy and tectonosedimentology Qilian Shan
... mechanism of the Tibetan Plateau formation and continental deformation. The timing of deformation events holds the key. For late-phase deformation and uplift of NE Tibet predicted from the models above, fission track analysis shows that the Qilian Shan experienced a rapid cooling in the Miocene (Geo ...
... mechanism of the Tibetan Plateau formation and continental deformation. The timing of deformation events holds the key. For late-phase deformation and uplift of NE Tibet predicted from the models above, fission track analysis shows that the Qilian Shan experienced a rapid cooling in the Miocene (Geo ...
Tectonic re-interpretation of the Banggai
... Abstract: High resolution multibeam bathymetric and seismic data from the area north of the Banggai-Sula Islands, Indonesia, provide a new insight into the geological history of the boundary between the East Sulawesi ophiolite, the Banggai-Sula microcontinent and the Molucca Sea collision zone. Majo ...
... Abstract: High resolution multibeam bathymetric and seismic data from the area north of the Banggai-Sula Islands, Indonesia, provide a new insight into the geological history of the boundary between the East Sulawesi ophiolite, the Banggai-Sula microcontinent and the Molucca Sea collision zone. Majo ...
extension systems - The Web site cannot be found
... mechanism, coeval lithospheric stretching and accretion of buoyant magma, is called rifting. It is called seafloor spreading once a rifted region becomes a plate boundary that creates new oceanic lithosphere as plates diverge from one another. The spreading centres shape elevated morphological forms ...
... mechanism, coeval lithospheric stretching and accretion of buoyant magma, is called rifting. It is called seafloor spreading once a rifted region becomes a plate boundary that creates new oceanic lithosphere as plates diverge from one another. The spreading centres shape elevated morphological forms ...
6 2D thermo-mecanical finite element models of n Contents
... Thermo-rheological and sedimentological changes acting during subduction in the overriding crust influence the landward formation of uplifted plateau-like terrains. Here, we analyze the impact of these factors on the mechanics of uplift of the southern margin of the Central Anatolian Plateau. We com ...
... Thermo-rheological and sedimentological changes acting during subduction in the overriding crust influence the landward formation of uplifted plateau-like terrains. Here, we analyze the impact of these factors on the mechanics of uplift of the southern margin of the Central Anatolian Plateau. We com ...
The OIB paradox - Do plumes exist?
... lowest values, most still have ∆Nb>0 suggesting that a relatively Nb-rich component (probably subducted ocean crust) is present in all OIB sources. The OIB source components seem to be present on all scales, from small streaks or blobs of enriched material (with positive ∆Nb) carried in the upper ma ...
... lowest values, most still have ∆Nb>0 suggesting that a relatively Nb-rich component (probably subducted ocean crust) is present in all OIB sources. The OIB source components seem to be present on all scales, from small streaks or blobs of enriched material (with positive ∆Nb) carried in the upper ma ...
Provenance (geology)
Provenance in geology, is the reconstruction of the history of sediments movements over time. The Earth is not a static but a dynamic planet, all rocks are subject to transition between the three main rock types, which are sedimentary, metamorphic, and igneous rocks (the rock cycle). Rocks exposed to the surface, sooner or later, are broken down into sediments. Sediments are expected to be able to provide evidence of the erosion history of their parent source rocks. The purpose of provenance study is to restore the tectonic, paleo-geographic and paleo-climatic history.