Convection in a partially molten metasedimentary crust? Insights
... emplacement. Pressure and maximum temperature estimates show that the metamorphic gradient during anatexis was 45 °C/km in the upper crust and 10 °C/km in the 7–8 km garnet-bearing migmatitic lower crust, controlled by biotite-breakdown melting reactions. Our petrological and geochemical studies ind ...
... emplacement. Pressure and maximum temperature estimates show that the metamorphic gradient during anatexis was 45 °C/km in the upper crust and 10 °C/km in the 7–8 km garnet-bearing migmatitic lower crust, controlled by biotite-breakdown melting reactions. Our petrological and geochemical studies ind ...
Proterozoic Rocks, Glacier NP
... – about 650 million years ago – judging by the Pan-African orogeny • the large-scale deformation that took place • in what are now the Southern Hemisphere ...
... – about 650 million years ago – judging by the Pan-African orogeny • the large-scale deformation that took place • in what are now the Southern Hemisphere ...
Age, Origin and Emplacement of Diamonds
... disciplines related to the physical, chemical, and mineralogic properties of diamonds, the roclzs in which they crystallize, as well as the roclzs that brought them to the surface and in which they now are found as primary deposits. Clearly, such a broad survey is beyond the scope of this article. T ...
... disciplines related to the physical, chemical, and mineralogic properties of diamonds, the roclzs in which they crystallize, as well as the roclzs that brought them to the surface and in which they now are found as primary deposits. Clearly, such a broad survey is beyond the scope of this article. T ...
Earth`s Systems - Kenai Peninsula Borough School District
... processes of melting, crystallization, weathering, deformation, and sedimentation, which act together to form minerals and rocks through the cycling of Earth’s materials.] [Assessment Boundary: Assessment does not include the identification and naming of minerals.] ...
... processes of melting, crystallization, weathering, deformation, and sedimentation, which act together to form minerals and rocks through the cycling of Earth’s materials.] [Assessment Boundary: Assessment does not include the identification and naming of minerals.] ...
bulletin of the geological society of america vol, 68
... generally so poor that details of structure cannot be worked out, but warping or folding in addition to possible faulting is inferred from topographic forms. The drainage pattern in low hills underlain by fanglomerate on the southeast, east and northeast flanks of the Yucca Grove Dome (Fig. 1) sugge ...
... generally so poor that details of structure cannot be worked out, but warping or folding in addition to possible faulting is inferred from topographic forms. The drainage pattern in low hills underlain by fanglomerate on the southeast, east and northeast flanks of the Yucca Grove Dome (Fig. 1) sugge ...
The Caribbean-North America-Cocos Triple Junction
... elements that help to understand the late Cenozoic evolution of this triple junction. In the Miocene, extension and shortening occurred south and north of the Motagua fault, respectively. This strain regime migrated northward to the Polochic fault after the late Miocene. This shift is interpreted as ...
... elements that help to understand the late Cenozoic evolution of this triple junction. In the Miocene, extension and shortening occurred south and north of the Motagua fault, respectively. This strain regime migrated northward to the Polochic fault after the late Miocene. This shift is interpreted as ...
54. mesozoic-tertiary tectonic evolution of the easternmost
... plate boundary? Woodside (1977) favored an origin of the Eratosthenes Seamount as an upthrust extension of thinned North African continental crust, but, alternatively, this unit could be a continental fragment surrounded by oceanic crust. The available evidence supports an origin of the easternmost ...
... plate boundary? Woodside (1977) favored an origin of the Eratosthenes Seamount as an upthrust extension of thinned North African continental crust, but, alternatively, this unit could be a continental fragment surrounded by oceanic crust. The available evidence supports an origin of the easternmost ...
Volcano instability induced by strike
... by basal strike-slip movement. The results of the analogue models demonstrate that edifice instability may be generated when strike-slip faults underlying a volcano move as a result of tectonic adjustment. This instability occurs on flanks of the volcano above the strike-slip shear. On the surface o ...
... by basal strike-slip movement. The results of the analogue models demonstrate that edifice instability may be generated when strike-slip faults underlying a volcano move as a result of tectonic adjustment. This instability occurs on flanks of the volcano above the strike-slip shear. On the surface o ...
Sudbury structure: geology and mineral deposits
... the Grenville Province (Figure 1). It comprises norites, quartz gabbro, and granophyres of the Sudbury Igneous Complex, the heterolithic breccias, mudstones, sUtstones and wackes of the Whitewater Group, and brecciated footwall rocks present around the Igneous Complex. In plan view, the Sudbury Igne ...
... the Grenville Province (Figure 1). It comprises norites, quartz gabbro, and granophyres of the Sudbury Igneous Complex, the heterolithic breccias, mudstones, sUtstones and wackes of the Whitewater Group, and brecciated footwall rocks present around the Igneous Complex. In plan view, the Sudbury Igne ...
19. contrasting characteristics of magmatic and
... The existence of magmatic granites is not doubted, because natural environments do produce temperatures above eutectic point(s) of granites in many places in the earth's crust. Nevertheless, the evidence that all granites are magmatic or that plutonic rocks cannot be altered to granites after emplac ...
... The existence of magmatic granites is not doubted, because natural environments do produce temperatures above eutectic point(s) of granites in many places in the earth's crust. Nevertheless, the evidence that all granites are magmatic or that plutonic rocks cannot be altered to granites after emplac ...
A DESCRIPTION OF s o m MINERALS
... called plates, that move slowly over the surface because of these forces. In some places, crustal plates collide with each other, and one plate slides under or moves laterally against the other. For example, the collision of two plates has lifted the sedimentary rocks of the Himalaya Mountains as mu ...
... called plates, that move slowly over the surface because of these forces. In some places, crustal plates collide with each other, and one plate slides under or moves laterally against the other. For example, the collision of two plates has lifted the sedimentary rocks of the Himalaya Mountains as mu ...
`emplacement` of an ophiolite?
... Troodos) and do not apply to many of the world's ophiolites. We have defined four prototype ophiolites based on different emplacement mechanisms: (1) 'Tethyan' ophiolites, emplaced over passive continental margins or microcontinents as a result of collisional events; (2) 'Cordilleran' ophiolites pro ...
... Troodos) and do not apply to many of the world's ophiolites. We have defined four prototype ophiolites based on different emplacement mechanisms: (1) 'Tethyan' ophiolites, emplaced over passive continental margins or microcontinents as a result of collisional events; (2) 'Cordilleran' ophiolites pro ...
Lower Continental Crust. - UCSB Earth Science
... (1990) assembled a database of rock compositions from Archean and post-Archean terrains recrystallized at >0.6 GPa. Huang et al. (2013) updated this database and added a compilation of amphibolite-facies samples. We augmented their granulite data with additional analyses from the literature, and her ...
... (1990) assembled a database of rock compositions from Archean and post-Archean terrains recrystallized at >0.6 GPa. Huang et al. (2013) updated this database and added a compilation of amphibolite-facies samples. We augmented their granulite data with additional analyses from the literature, and her ...
rocks and minerals - OSU Extension Catalog
... called plates, that move slowly over the surface because of these forces. In some places, crustal plates collide with each other, and one plate slides under or moves laterally against the other. For example, the collision of two plates has lifted the sedimentary rocks of the Himalaya Mountains as mu ...
... called plates, that move slowly over the surface because of these forces. In some places, crustal plates collide with each other, and one plate slides under or moves laterally against the other. For example, the collision of two plates has lifted the sedimentary rocks of the Himalaya Mountains as mu ...
About Earthquake
... The plate tectonics theory is a starting point for understanding the forces within the Earth that cause earthquakes. Plates are thick slabs of rock that make up the outermost 100 kilometers or so of the Earth. Geologists use the term "tectonics" to describe deformation of the Earth's crust, the forc ...
... The plate tectonics theory is a starting point for understanding the forces within the Earth that cause earthquakes. Plates are thick slabs of rock that make up the outermost 100 kilometers or so of the Earth. Geologists use the term "tectonics" to describe deformation of the Earth's crust, the forc ...
A new model of lunar crust: asymmetry in crustal composition... Tomoko Arai , Hiroshi Takeda , Akira Yamaguchi
... (FAN), while those of the latter include Mg-suite rocks plus some rocks enriched in alkali elements, termed alkali-suite rocks. There is another outstanding group, called KREEP, which is extremely enriched in alkalis and incompatible trace elements, such as K, rare earth elements (REEs) and P. They ...
... (FAN), while those of the latter include Mg-suite rocks plus some rocks enriched in alkali elements, termed alkali-suite rocks. There is another outstanding group, called KREEP, which is extremely enriched in alkalis and incompatible trace elements, such as K, rare earth elements (REEs) and P. They ...
Crustal flow pattern beneath the Tibetan Plateau constrained by
... 4. The possible crustal flow pattern constrained by Lg attenuation The partially molten layer in the middle or lower crust is generated by the continental crust thickening and behaves like a fluid over the formation time scale of the Tibetan Plateau (e.g., Nelson et al., 1996). It is expected that the ...
... 4. The possible crustal flow pattern constrained by Lg attenuation The partially molten layer in the middle or lower crust is generated by the continental crust thickening and behaves like a fluid over the formation time scale of the Tibetan Plateau (e.g., Nelson et al., 1996). It is expected that the ...
Week 27 - 2016-2017
... Objective: TLW identify convergent, divergent, & transformation of plate tectonic ...
... Objective: TLW identify convergent, divergent, & transformation of plate tectonic ...
Extensional collapse of the Tibetan Plateau
... 0.25, respectively. The density of the crust and the upper mantle are taken to be 2800 and 3300 kg m-3, respectively. Other specific parameter values are given when the numerical experiments are presented. [8] The present state of deviatoric stresses within the Tibetan Plateau results from the mecha ...
... 0.25, respectively. The density of the crust and the upper mantle are taken to be 2800 and 3300 kg m-3, respectively. Other specific parameter values are given when the numerical experiments are presented. [8] The present state of deviatoric stresses within the Tibetan Plateau results from the mecha ...
Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario
... stocks, and ultramafic (komatiitic) volcanic flows and sills. The second type is exploited principally for PGE, which are associated with sparsely dispersed sulphides in very large to medium-sized, typically mafic/ultramafic layered intrusions. In Ni-Cu sulphide deposits (the first type), Ni constit ...
... stocks, and ultramafic (komatiitic) volcanic flows and sills. The second type is exploited principally for PGE, which are associated with sparsely dispersed sulphides in very large to medium-sized, typically mafic/ultramafic layered intrusions. In Ni-Cu sulphide deposits (the first type), Ni constit ...
55. The Western Rockall Plateau
... high near 58°N that narrows southward into one of a series of northeast-southwest trending basement ridges associated with magnetic anomalies of that trend (Figures 3,5). These ridges parallel both the slope and the linear magnetic anomalies recorded in the adjacent oceanic crust. The outermost ridg ...
... high near 58°N that narrows southward into one of a series of northeast-southwest trending basement ridges associated with magnetic anomalies of that trend (Figures 3,5). These ridges parallel both the slope and the linear magnetic anomalies recorded in the adjacent oceanic crust. The outermost ridg ...
Geoscientific Report GR2011-1
... between the northern Flin Flon Belt and south-central part of the Flin Flon Belt............................................................................4 Figure 5: Ternary diagrams (Al2O3–[FeOT+TiO2]–MgO) and ([Na2O+K2O]–FeOT–MgO) for mafic to felsic arc volcanic rocks in the northern Flin Flon ...
... between the northern Flin Flon Belt and south-central part of the Flin Flon Belt............................................................................4 Figure 5: Ternary diagrams (Al2O3–[FeOT+TiO2]–MgO) and ([Na2O+K2O]–FeOT–MgO) for mafic to felsic arc volcanic rocks in the northern Flin Flon ...
Large igneous province
A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including liquid rock (intrusive) or volcanic rock formations (extrusive), when hot magma extrudes from inside the Earth and flows out. The source of many or all LIPs is variously attributed to mantle plumes or to processes associated with plate tectonics. Types of LIPs can include large volcanic provinces (LVP), created through flood basalt and large plutonic provinces (LPP). Eleven distinct flood basalt episodes occurred in the past 250 million years, creating volcanic provinces, which coincided with mass extinctions in prehistoric times. Formation depends on a range of factors, such as continental configuration, latitude, volume, rate, duration of eruption, style and setting (continental vs. oceanic), the preexisting climate state, and the biota resilience to change.