Earth and Planetary Science Letters
... the typical depth to the subducting plate beneath arc volcanoes, estimated at ~ 110 km, (e.g. 108 ± 14 km (Tatsumi and Eggins, 1995); 112 ± 19 km (Tatsumi, 1986) and 124 ± 38 km (Gill, 1981)). Compared to most Kamchatka volcanoes, the geochemistry of KV eruptive products indicates more complex magma ...
... the typical depth to the subducting plate beneath arc volcanoes, estimated at ~ 110 km, (e.g. 108 ± 14 km (Tatsumi and Eggins, 1995); 112 ± 19 km (Tatsumi, 1986) and 124 ± 38 km (Gill, 1981)). Compared to most Kamchatka volcanoes, the geochemistry of KV eruptive products indicates more complex magma ...
Plateau uplift in western Canada caused by lithospheric
... the Canadian National Seismograph Network (CNSN), as well as 67 temporary stations with 9 from the Alberta Telemetered Seismograph Network (ATSN), 19 from the Canadian Rockies and Alberta Network (CRANE) and 39 from USArray. We selected 583 shallow earthquakes within an epicentral distance of 20◦ –1 ...
... the Canadian National Seismograph Network (CNSN), as well as 67 temporary stations with 9 from the Alberta Telemetered Seismograph Network (ATSN), 19 from the Canadian Rockies and Alberta Network (CRANE) and 39 from USArray. We selected 583 shallow earthquakes within an epicentral distance of 20◦ –1 ...
Dike induced Faults
... II inclined normal fault (Fig. 4b). The local stress field is affected by variation in stresses because of magma supply and brittle faulting. A normal fault concentrates stresses in its tip zone and releases stress on both sides (Pollard and Aydin, 1984). The fault continues its growing and propagat ...
... II inclined normal fault (Fig. 4b). The local stress field is affected by variation in stresses because of magma supply and brittle faulting. A normal fault concentrates stresses in its tip zone and releases stress on both sides (Pollard and Aydin, 1984). The fault continues its growing and propagat ...
The volcanic–plutonic connection as a stage for
... (Lindsay et al., 2001; Bachmann et al., 2002; Maughan et al., 2002), a rare assemblage in crystal-poor volcanic rocks (Nakada, 1991; Deer et al., 1992) but common in granodiorite batholiths (e.g., Bateman and Chappell, 1979). One noticeable difference is the higher abundance of quartz and K-feldspar ...
... (Lindsay et al., 2001; Bachmann et al., 2002; Maughan et al., 2002), a rare assemblage in crystal-poor volcanic rocks (Nakada, 1991; Deer et al., 1992) but common in granodiorite batholiths (e.g., Bateman and Chappell, 1979). One noticeable difference is the higher abundance of quartz and K-feldspar ...
types of volcanoes
... 600°C), rocks will melt, separating into two parts – one is a liquid and one is a gas. The hot, thick liquid that is formed is called magma. The gas that is released during melting increases the pressure deep in the earth’s core, causing the magma to rise and collect in large underground ...
... 600°C), rocks will melt, separating into two parts – one is a liquid and one is a gas. The hot, thick liquid that is formed is called magma. The gas that is released during melting increases the pressure deep in the earth’s core, causing the magma to rise and collect in large underground ...
Mantle Plumes and Intraplate Volcanism Volcanism on the Earth
... Volcanism on the Earth • Mid-ocean ridges (>90% of the volcanism) ...
... Volcanism on the Earth • Mid-ocean ridges (>90% of the volcanism) ...
Modification of the Continental Crust by Subduction Zone
... occur over vast areas (Figure 1). The region composes one of the youngest and largest active silicic volcanic provinces on Earth with recent caldera formation. It contains over 20 calderas and numerous ignimbrites (large ash flow sheets) less than 10 Ma as well as an estimated 50 active or recently ...
... occur over vast areas (Figure 1). The region composes one of the youngest and largest active silicic volcanic provinces on Earth with recent caldera formation. It contains over 20 calderas and numerous ignimbrites (large ash flow sheets) less than 10 Ma as well as an estimated 50 active or recently ...
Modification of the Continental Crust by Subduction Zone
... occur over vast areas (Figure 1). The region composes one of the youngest and largest active silicic volcanic provinces on Earth with recent caldera formation. It contains over 20 calderas and numerous ignimbrites (large ash flow sheets) less than 10 Ma as well as an estimated 50 active or recently ...
... occur over vast areas (Figure 1). The region composes one of the youngest and largest active silicic volcanic provinces on Earth with recent caldera formation. It contains over 20 calderas and numerous ignimbrites (large ash flow sheets) less than 10 Ma as well as an estimated 50 active or recently ...
Crust-mantle structures and Neogene
... et al., 1993). This implies that the crust was molten above the migrating mantle dome where CO2-dominated fluids exhaling from the mantle were accumulated. In this regard, several petrologists propose [Crisci et al. (1991) and reference herein] a metasomatized mantle as the source of the high potash ...
... et al., 1993). This implies that the crust was molten above the migrating mantle dome where CO2-dominated fluids exhaling from the mantle were accumulated. In this regard, several petrologists propose [Crisci et al. (1991) and reference herein] a metasomatized mantle as the source of the high potash ...
Linking rift propagation barriers to excess magmatism at volcanic
... In agreement with observations from the North and South Atlantic, and as imposed by the model’s boundary conditions, break-up in the model occurs via rift propagation (Figs. 2B and 2C). In the same manner, the area affected by decompression melting (between 65 km and 15 km depth beneath the rift cen ...
... In agreement with observations from the North and South Atlantic, and as imposed by the model’s boundary conditions, break-up in the model occurs via rift propagation (Figs. 2B and 2C). In the same manner, the area affected by decompression melting (between 65 km and 15 km depth beneath the rift cen ...
Document
... mudstones which locally overlie, or are interbedded with basaltic volcanic rocks. The oldest cherts, referred to as the Raven Gill Formation, occur within the Leadhills Imbricate Zone (LIZ) (Fig. 1). These locally mottled cherts commonly contain radiolaria which are altered or poorly preserved due t ...
... mudstones which locally overlie, or are interbedded with basaltic volcanic rocks. The oldest cherts, referred to as the Raven Gill Formation, occur within the Leadhills Imbricate Zone (LIZ) (Fig. 1). These locally mottled cherts commonly contain radiolaria which are altered or poorly preserved due t ...
Genesis of the Neogene to Quaternary volcanism in the Carpathian
... with time, which is consistent with magmatic activity in a continuously thinning continental plate. Calc-alkaline volcanism along the Eastern Carpathians was mostly postcollisional and could have been related to slab break-off processes. However, the fairly young (<1.5 Ma) potassic magmatism at the ...
... with time, which is consistent with magmatic activity in a continuously thinning continental plate. Calc-alkaline volcanism along the Eastern Carpathians was mostly postcollisional and could have been related to slab break-off processes. However, the fairly young (<1.5 Ma) potassic magmatism at the ...
Magnesium isotopic composition of the lower continental crust
... differentiation make Mg isotopes a potentially powerful tracer of the influence of chemical weathering on the continental crust composition. Magnesium isotopic composition of the upper continental crust is highly heterogenous [1], and on avarage heavier than the mantle [e.g., 2]. By contrast, the Mg ...
... differentiation make Mg isotopes a potentially powerful tracer of the influence of chemical weathering on the continental crust composition. Magnesium isotopic composition of the upper continental crust is highly heterogenous [1], and on avarage heavier than the mantle [e.g., 2]. By contrast, the Mg ...
Mantle transition zone thickness beneath Cameroon
... 42 Ma, and became widespread along the CVL during the Oligocene (Marzoli et al. 1999, 2000). Many of the volcanic centres have had activity in the past one million years (Fitton & Dunlop 1985), with the most recent activity occurring at Mt. Cameroon. The continental portion of the CVL developed with ...
... 42 Ma, and became widespread along the CVL during the Oligocene (Marzoli et al. 1999, 2000). Many of the volcanic centres have had activity in the past one million years (Fitton & Dunlop 1985), with the most recent activity occurring at Mt. Cameroon. The continental portion of the CVL developed with ...
Mesozoic extensional and strike-slip fault systems in magmatic arc
... high structural levels to allow ductile defortnation of their \.val1 rocks at temperatures as high as the upper amphibolite facies. Steeply-dipping, ductile shear zones in the wall rocks of arc plutons are up to 800111 wide, exhibit intense mylonitic fabric and contain steeply-plunging strctching fa ...
... high structural levels to allow ductile defortnation of their \.val1 rocks at temperatures as high as the upper amphibolite facies. Steeply-dipping, ductile shear zones in the wall rocks of arc plutons are up to 800111 wide, exhibit intense mylonitic fabric and contain steeply-plunging strctching fa ...
Geothermal Development in Eritrea
... The two main geothermal prospects, the Alid and NabroDubbi are both located within the Danakil depression; the structural axis that connects the African Rift System with the Red-Sea (Figure 2). The development of the Danakil depression occurred in two phases namely: (i) the continental rifting phase ...
... The two main geothermal prospects, the Alid and NabroDubbi are both located within the Danakil depression; the structural axis that connects the African Rift System with the Red-Sea (Figure 2). The development of the Danakil depression occurred in two phases namely: (i) the continental rifting phase ...
Mantle-drip magmatism beneath the Altiplano
... Pyroxenites inferred to have sourced the plateau magmas described here were most likely clinopyroxenites with or without garnet, which typically complement large arc systems at depth (Ducea and Saleeby, 1998). Rare earth element (REE) patterns suggest that garnet may have been present in the pyroxen ...
... Pyroxenites inferred to have sourced the plateau magmas described here were most likely clinopyroxenites with or without garnet, which typically complement large arc systems at depth (Ducea and Saleeby, 1998). Rare earth element (REE) patterns suggest that garnet may have been present in the pyroxen ...
Rheological Response to Tectonic and Volcanic
... Iceland is one of the few places in the world where a Mid-Oceanic Ridge (MOR) is exposed on land, and this gives good opportunity to study geodynamic processes. Spreading of MidAtlantic Ocean Ridge (MAR) segments in Iceland began ~60 million years ago. The MAR segments in Iceland have a divergent sp ...
... Iceland is one of the few places in the world where a Mid-Oceanic Ridge (MOR) is exposed on land, and this gives good opportunity to study geodynamic processes. Spreading of MidAtlantic Ocean Ridge (MAR) segments in Iceland began ~60 million years ago. The MAR segments in Iceland have a divergent sp ...
Dissertation - WordPress.com
... in the volcano. This indicates whether an eruption is imminent. It is also used to predict hazards that may occur as the magma would be more dangerous if its viscosity is low as it can travel quicker and further so scientists and governments would be able to assess the viscosity of the magma beforeh ...
... in the volcano. This indicates whether an eruption is imminent. It is also used to predict hazards that may occur as the magma would be more dangerous if its viscosity is low as it can travel quicker and further so scientists and governments would be able to assess the viscosity of the magma beforeh ...
The Making of the Japan Sea and the Japanese Mountains
... The first indication of rifting is often the extrusion of huge amounts of low-silica lava (basalt) without formation of volcanoes per se. In East Asia, such “flood basalts” as they are called occur on the North China Mainland, while Japan was subjected primarily to the extru sion of higher-silica v ...
... The first indication of rifting is often the extrusion of huge amounts of low-silica lava (basalt) without formation of volcanoes per se. In East Asia, such “flood basalts” as they are called occur on the North China Mainland, while Japan was subjected primarily to the extru sion of higher-silica v ...
Print this article
... years. South of it the convergence rate at the margin has decreased frwn 5.5 cmlyrat ninemy. to3.6 cmlyr (perpendicular subduction of 3.2 cmlyr) in the past one million years, a result which is Similar to that of Chase etal. (1975). However, to the north of it (the Explorer plate) convergence at the ...
... years. South of it the convergence rate at the margin has decreased frwn 5.5 cmlyrat ninemy. to3.6 cmlyr (perpendicular subduction of 3.2 cmlyr) in the past one million years, a result which is Similar to that of Chase etal. (1975). However, to the north of it (the Explorer plate) convergence at the ...
Eds. I. S. Evans, R. Dikau, E. Tokunaga, H. Ohmori... © by TERRAPUB, Tokyo, 2003.
... respectively 60, 90 and 180 million years. The maximum age difference reaches 120 million years. Such time interval is comparable to the duration of major geological epochs and periods. For that reason, the above-mentioned segments present an ideal possibility for comparing them with each other and ...
... respectively 60, 90 and 180 million years. The maximum age difference reaches 120 million years. Such time interval is comparable to the duration of major geological epochs and periods. For that reason, the above-mentioned segments present an ideal possibility for comparing them with each other and ...
Mantle Influence, Rifting and Magmatism in the East African Rift
... 3.2.3 The Southwestern EARS Branches The seismically and hydro-thermally active members of this tectonic regime include the Upemba, Mweru and Bangweulu half grabens and the various minor structures of Eastern DRC. They are found in the southern and central parts of the extensive Mitumba Mountains, a ...
... 3.2.3 The Southwestern EARS Branches The seismically and hydro-thermally active members of this tectonic regime include the Upemba, Mweru and Bangweulu half grabens and the various minor structures of Eastern DRC. They are found in the southern and central parts of the extensive Mitumba Mountains, a ...
pdf-file - Art Periods
... shift in the high-velocity anomaly underlying the central part may be caused by a north to south decrease in plate age and hydration across the Valdivia Fracture Zone, and may explain why a Central Valley is absent in this segment of the margin. The low La/Yb ratios in the volcanic rocks from Villar ...
... shift in the high-velocity anomaly underlying the central part may be caused by a north to south decrease in plate age and hydration across the Valdivia Fracture Zone, and may explain why a Central Valley is absent in this segment of the margin. The low La/Yb ratios in the volcanic rocks from Villar ...
Yogo_et_al._Slab Edg.. - UNC
... Paci®c plate somewhere beneath the western Aleutians (Fig. 5). The location of the tear is not constrained by seismicity, but the geochemistry of active western Aleutian magmatism suggests that it may be located between Buldir and Attu islands, where the arc switches from convergent to strike-slip m ...
... Paci®c plate somewhere beneath the western Aleutians (Fig. 5). The location of the tear is not constrained by seismicity, but the geochemistry of active western Aleutian magmatism suggests that it may be located between Buldir and Attu islands, where the arc switches from convergent to strike-slip m ...
Northern Cordilleran Volcanic Province
The Northern Cordilleran Volcanic Province (NCVP), formerly known as the Stikine Volcanic Belt, is a geologic province defined by the occurrence of Miocene to Holocene volcanoes in the Pacific Northwest of North America. This belt of volcanoes extends roughly north-northwest from northwestern British Columbia and the Alaska Panhandle through Yukon to the Southeast Fairbanks Census Area of far eastern Alaska, in a corridor hundreds of kilometres wide. It is the most recently defined volcanic province in the Western Cordillera. It has formed due to extensional cracking of the North American continent—similar to other on-land extensional volcanic zones, including the Basin and Range Province and the East African Rift. Although taking its name from the Western Cordillera, this term is a geologic grouping rather than a geographic one. The southmost part of the NCVP has more, and larger, volcanoes than does the rest of the NCVP; further north it is less clearly delineated, describing a large arch that sways westward through central Yukon.At least four large volcanoes are grouped with the Northern Cordilleran Volcanic Province, including Hoodoo Mountain in the Boundary Ranges, the Mount Edziza volcanic complex on the Tahltan Highland, and Level Mountain and Heart Peaks on the Nahlin Plateau. These four volcanoes have volumes of more than 15 km3 (3.6 cu mi), the largest and oldest which is Level Mountain with an area of 1,800 km2 (690 sq mi) and a volume of more than 860 km3 (210 cu mi). Apart from the large volcanoes, several smaller volcanoes exist throughout the Northern Cordilleran Volcanic Province, including cinder cones which are widespread throughout the volcanic zone. Most of these small cones have been sites of only one volcanic eruption; this is in contrast to the larger volcanoes throughout the volcanic zone, which have had more than one volcanic eruption throughout their history.The Northern Cordilleran Volcanic Province is part of an area of intensive earthquake and volcanic activity around the Pacific Ocean called the Pacific Ring of Fire. However, the Northern Cordilleran Volcanic Province is commonly interpreted to be part of a gap in the Pacific Ring of Fire between the Cascade Volcanic Arc further south and the Aleutian Arc further north. But the Northern Cordilleran Volcanic Province is recognized to include over 100 independent volcanoes that have been active in the past 1.8 million years. At least three of them have erupted in the past 360 years, making it the most active volcanic area in Canada. Nevertheless, the dispersed population within the volcanic zone has witnessed few eruptions due to remoteness and the infrequent volcanic activity.