Glossary Accommodation zone—Accommodation zone is the zone
... Breakaway blocks – Defined as crustal blocks of various sizes, which separate detachment fault systems that form in distal rifted margins. Similar to extensional allochthons and hanging-wall blocks, breakaway blocks consist of pre-rift sediments. In contrary to extensional allochthons and hanging-wa ...
... Breakaway blocks – Defined as crustal blocks of various sizes, which separate detachment fault systems that form in distal rifted margins. Similar to extensional allochthons and hanging-wall blocks, breakaway blocks consist of pre-rift sediments. In contrary to extensional allochthons and hanging-wa ...
Geophysical-petrological model of the crust and upper mantle in the
... We used a 2-D numerical code (LitMod-2D) [Afonso et al., 2008], which combines geophysical and petrological data to infer the crustal and upper mantle structure down to 410 km depth. The code calculates the 2-D distribution of temperature, density, and mantle seismic velocities and the resulting sur ...
... We used a 2-D numerical code (LitMod-2D) [Afonso et al., 2008], which combines geophysical and petrological data to infer the crustal and upper mantle structure down to 410 km depth. The code calculates the 2-D distribution of temperature, density, and mantle seismic velocities and the resulting sur ...
Adakitic magmas: modern analogues of Archaean granitoids
... Both geochemical and experimental petrological research indicate that Archaean continental crust was generated by partial melting of an Archaean tholeiite transformed into a garnet-bearing amphibolite or eclogite. The geodynamic context of tholeiite melting is the subject of controversy. It is assum ...
... Both geochemical and experimental petrological research indicate that Archaean continental crust was generated by partial melting of an Archaean tholeiite transformed into a garnet-bearing amphibolite or eclogite. The geodynamic context of tholeiite melting is the subject of controversy. It is assum ...
The role of frictional strength on plate coupling at the subduction
... 1. Introduction [2] The subduction of an oceanic plate beneath an overriding continental or oceanic plate is primarily driven by slab pull. The corresponding cooling and contraction of the descending oceanic lithosphere, as well as the density increase caused by prograde metamorphic reactions at dep ...
... 1. Introduction [2] The subduction of an oceanic plate beneath an overriding continental or oceanic plate is primarily driven by slab pull. The corresponding cooling and contraction of the descending oceanic lithosphere, as well as the density increase caused by prograde metamorphic reactions at dep ...
A trace element perspective on the source of ocean island basalts
... petrology, trace element/isotope geochemistry and mineral physics that ancient subducted ocean crust (SOC) cannot be the major source material for OIB. Among many other reasons, SOC, if subducted to the lower mantle, will not return in bulk to the upper mantle, but will sink irreversibly to the base ...
... petrology, trace element/isotope geochemistry and mineral physics that ancient subducted ocean crust (SOC) cannot be the major source material for OIB. Among many other reasons, SOC, if subducted to the lower mantle, will not return in bulk to the upper mantle, but will sink irreversibly to the base ...
Flow and melting of a heterogeneous mantle
... melt generation and accumulation from a heterogeneous mantle. The concept that compositional heterogeneity is present in the mantle as veins, streaks, or blobs smaller than typical volumes of upper mantle melting zones is widely discussed in the geochemical literature [17–22]. Compelling evidence fo ...
... melt generation and accumulation from a heterogeneous mantle. The concept that compositional heterogeneity is present in the mantle as veins, streaks, or blobs smaller than typical volumes of upper mantle melting zones is widely discussed in the geochemical literature [17–22]. Compelling evidence fo ...
GLG101online_08A_Metamorphism_MCC_Leighty
... These notes and web links are your primary “lecture” content in this class. Additionally, various articles are assigned each week to supplement this “lecture” information. I believe you’ll have enough information to reference without having to purchase a costly textbook. These lecture notes are ver ...
... These notes and web links are your primary “lecture” content in this class. Additionally, various articles are assigned each week to supplement this “lecture” information. I believe you’ll have enough information to reference without having to purchase a costly textbook. These lecture notes are ver ...
PDF (Chapter 11. Evolution of the Mantle)
... Fluids and melts are LIL-enriched, and they tend to migrate upward. Sediments and altered ocean crust, also LIL-enriched, re-enter the upper mantle at subduction zones. Thus there are several reasons to believe that the shallow mantle serves as a scavenger of incompatible elements, including the rad ...
... Fluids and melts are LIL-enriched, and they tend to migrate upward. Sediments and altered ocean crust, also LIL-enriched, re-enter the upper mantle at subduction zones. Thus there are several reasons to believe that the shallow mantle serves as a scavenger of incompatible elements, including the rad ...
Crustal collapse, mantle upwelling, and Cenozoic extension in the
... may decouple from the mantle lithosphere, because the extensional forces arising from an overthickenedcrust are limited to the crust, while the rheology of continental lithosphereis intrinsically stratified. Even when the mantle lithosphere is mechanically coupled to the crust, thermomechanicalmodel ...
... may decouple from the mantle lithosphere, because the extensional forces arising from an overthickenedcrust are limited to the crust, while the rheology of continental lithosphereis intrinsically stratified. Even when the mantle lithosphere is mechanically coupled to the crust, thermomechanicalmodel ...
Chapter 17. The Other Isotopes
... assumed to extend to the major mantle discontinuity near 650 km depth. A parallel geochemical hypothesis at the time was that some magmas represented melts from a 'primitive' mantle reservoir that had survived from the accretion of the Earth without any degassing, melting or melt extraction. The ass ...
... assumed to extend to the major mantle discontinuity near 650 km depth. A parallel geochemical hypothesis at the time was that some magmas represented melts from a 'primitive' mantle reservoir that had survived from the accretion of the Earth without any degassing, melting or melt extraction. The ass ...
Is the rate of supercontinent assembly changing with time?
... velocity between supercontinent assemblies and breakups. Assembly of Nuna at 1700–1500 Ma correlates with very low collision rates, whereas assemblies of Rodinia and Gondwana at 1000–850 and 650–350 Ma, respectively correspond to moderate to high rates. Very low collision rates occur at times of sup ...
... velocity between supercontinent assemblies and breakups. Assembly of Nuna at 1700–1500 Ma correlates with very low collision rates, whereas assemblies of Rodinia and Gondwana at 1000–850 and 650–350 Ma, respectively correspond to moderate to high rates. Very low collision rates occur at times of sup ...
THE TECTONIC RELATIONSHIPS OF THE HILLABEE CHLORITE
... into three units: the Heflin Phyllite, the Abel Gap Formation, and the Chulafinnee Schist. Tull (1977) interpreted the Hollins Line fault as a major thrust fault and included the Hillabee within the Talladega block. Tull et al. (1978) postulated that the Hillabee was of mafic extrusive origin. Tull ...
... into three units: the Heflin Phyllite, the Abel Gap Formation, and the Chulafinnee Schist. Tull (1977) interpreted the Hollins Line fault as a major thrust fault and included the Hillabee within the Talladega block. Tull et al. (1978) postulated that the Hillabee was of mafic extrusive origin. Tull ...
Chapter 1- INTRODUCTION 1.1. Mantle Rocks This study is
... Mantle xenoliths are fragments of the Earth’s mantle that range up to sizes in excess of 1 m across, frequently transported to the surface via volcanic rocks that are dominantly alkaline in nature. Mantle xenoliths provide snapshots of the lithospheric mantle beneath particular regions at the time ...
... Mantle xenoliths are fragments of the Earth’s mantle that range up to sizes in excess of 1 m across, frequently transported to the surface via volcanic rocks that are dominantly alkaline in nature. Mantle xenoliths provide snapshots of the lithospheric mantle beneath particular regions at the time ...
compositional and thermal differences between lithospheric and
... asthenosphere and the cold thickened lithospheric mantle. Generally, standard delamination models have neglected density changes within the crust and the lithospheric mantle, which occur due to phase transitions and compositional variations upon changes of P-T parameters. Our attention is focused on ...
... asthenosphere and the cold thickened lithospheric mantle. Generally, standard delamination models have neglected density changes within the crust and the lithospheric mantle, which occur due to phase transitions and compositional variations upon changes of P-T parameters. Our attention is focused on ...
Redalyc.Long-term evolution of subduction zones and the
... 1969; Atwater, 1970, 1989). The magmatism covers a zone more than 1000 km wide. An eastward shift of igneous activity (Lindgren, 1915) took place during Late Mesozoic to Early Cenozoic times (Lipman et al., 1971; Snyder et al., 1976). These features were interpreted in terms of two subparallel subdu ...
... 1969; Atwater, 1970, 1989). The magmatism covers a zone more than 1000 km wide. An eastward shift of igneous activity (Lindgren, 1915) took place during Late Mesozoic to Early Cenozoic times (Lipman et al., 1971; Snyder et al., 1976). These features were interpreted in terms of two subparallel subdu ...
PDF (Chapter 10. Isotopes)
... relative to the shallow mantle. It may be that basalts originate primarily from only one of these reservoirs and that the trace-element and isotopic diversity is acquired when they traverse the shallow mantle on their way to the surface. The crust is extremely enriched in many of the socalled incomp ...
... relative to the shallow mantle. It may be that basalts originate primarily from only one of these reservoirs and that the trace-element and isotopic diversity is acquired when they traverse the shallow mantle on their way to the surface. The crust is extremely enriched in many of the socalled incomp ...
Contents and Preface
... comprehensive discussion of topics, including laboratory studies of physical properties of crustal and upper mantle rocks, methods in lithosphere research, and lithosphere structure in xiii ...
... comprehensive discussion of topics, including laboratory studies of physical properties of crustal and upper mantle rocks, methods in lithosphere research, and lithosphere structure in xiii ...
Characteristic thermal regimes of plate tectonics
... Hansen et al., 2006; Loddoch et al., 2006). A scenario of changing from a stagnant-lid to a mobile-lid mode via an episodic regime is one possible evolutionary path for Earth. Indeed, Davies (1995) has suggested a punctuated tectonic evolution for Earth in which the Archean might be characterized by ...
... Hansen et al., 2006; Loddoch et al., 2006). A scenario of changing from a stagnant-lid to a mobile-lid mode via an episodic regime is one possible evolutionary path for Earth. Indeed, Davies (1995) has suggested a punctuated tectonic evolution for Earth in which the Archean might be characterized by ...
Garnet: Common Mineral, Uncommonly Useful
... metamorphic rocks. Garnet may form in rocks that are sufficiently rich in Al (or Fe3+ or Cr) and in many metamorphic contexts (i.e. contact, regional, and subductionrelated metamorphism). It usually forms at temperatures above ~400 °C and pressures above ~0.4 GPa (e.g. Spear 1993; Caddick and Kohn 2 ...
... metamorphic rocks. Garnet may form in rocks that are sufficiently rich in Al (or Fe3+ or Cr) and in many metamorphic contexts (i.e. contact, regional, and subductionrelated metamorphism). It usually forms at temperatures above ~400 °C and pressures above ~0.4 GPa (e.g. Spear 1993; Caddick and Kohn 2 ...
Major and Trace Element Composition of the Depleted MORB
... The trace element composition of the depleted upper mantle (DMM) is a fundamental parameter in modeling the generation of mid-ocean ridge basalts (MORBs), calculating the crustmantle mass balance, and establishing the chemical and thermal evolution of the stratified Earth. To date, all attempts to e ...
... The trace element composition of the depleted upper mantle (DMM) is a fundamental parameter in modeling the generation of mid-ocean ridge basalts (MORBs), calculating the crustmantle mass balance, and establishing the chemical and thermal evolution of the stratified Earth. To date, all attempts to e ...
American Journal of Science - gemoc
... Incompatible elements and Nd isotopes.—The Nb/Th ratio in non-arc oceanic basalts has been used as a proxy for the growth of continental crust, assuming that continental crust has been extracted from the mantle leaving a depleted trace element signature in ...
... Incompatible elements and Nd isotopes.—The Nb/Th ratio in non-arc oceanic basalts has been used as a proxy for the growth of continental crust, assuming that continental crust has been extracted from the mantle leaving a depleted trace element signature in ...
Radiogenic Isotope Geochemistry of the Mantle
... the region occupied by the oceanic basalt data is often referred to as the “mantle array”. The second observation is that, although there is overlap, MORB have the lower 87Sr/86Sr ratios and highest εNd than OIB. Variations in radiogenic isotope ratios in basalts result from variations in parent-dau ...
... the region occupied by the oceanic basalt data is often referred to as the “mantle array”. The second observation is that, although there is overlap, MORB have the lower 87Sr/86Sr ratios and highest εNd than OIB. Variations in radiogenic isotope ratios in basalts result from variations in parent-dau ...
Crustal growth at active continental margins: Numerical
... The rectangular grid with 2041 201 nodes is non-uniform, resulting in a high resolution (1 km 1 km) area in the center of the model covering 1500 km horizontally, while the rest of the model remains at a lower resolution (5 1 km). The oceanic crust consists of 2 km of hydrated basalts and 5 km ...
... The rectangular grid with 2041 201 nodes is non-uniform, resulting in a high resolution (1 km 1 km) area in the center of the model covering 1500 km horizontally, while the rest of the model remains at a lower resolution (5 1 km). The oceanic crust consists of 2 km of hydrated basalts and 5 km ...
Inclusions in Sublithospheric Diamonds
... For the growth of macrodiamonds, a local enrichment mechanism for carbon is needed. Within the lithosphere, this is probably accomplished by redox fronts, where reducing fluids encounter oxidized rocks or vice versa. The deep asthenosphere and transition zone are expected to be fairly well mixed and ...
... For the growth of macrodiamonds, a local enrichment mechanism for carbon is needed. Within the lithosphere, this is probably accomplished by redox fronts, where reducing fluids encounter oxidized rocks or vice versa. The deep asthenosphere and transition zone are expected to be fairly well mixed and ...
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.