Volcanic Activity
... Cascade Range (Washington, Oregon, northern California), or on the islands of Hawaii. The Hawaiian Islands represent an exception to the rule that Pacific volcanoes are located along the boundary of the oceanic plate. Volcanoes located within the interiors of plates are typically the result of volca ...
... Cascade Range (Washington, Oregon, northern California), or on the islands of Hawaii. The Hawaiian Islands represent an exception to the rule that Pacific volcanoes are located along the boundary of the oceanic plate. Volcanoes located within the interiors of plates are typically the result of volca ...
Asymmetric plume-ridge interaction around Iceland: The Kolbeinsey
... densities. However, we infer that the lower crust beneath central Iceland is considerably denser than that beneath the adjacent ridges. Crustal thickness and geochemical patterns suggest that deep melting is spatially limited and asymmetric about Iceland while shallow melting is enhanced over a broa ...
... densities. However, we infer that the lower crust beneath central Iceland is considerably denser than that beneath the adjacent ridges. Crustal thickness and geochemical patterns suggest that deep melting is spatially limited and asymmetric about Iceland while shallow melting is enhanced over a broa ...
Continental crust under compression: A seismic refraction study of
... distribution in age and origin of basement rocks of South Island reveals two very distinct metamorphic belts, the Western and Eastern Province, which are joined by a suture called the Median Tectonic Zone (MTZ, Figure 2) [Landis and Coombs, 1967; Bradshaw, 1993; Kimbrough et al., 1993]. The 450 km ...
... distribution in age and origin of basement rocks of South Island reveals two very distinct metamorphic belts, the Western and Eastern Province, which are joined by a suture called the Median Tectonic Zone (MTZ, Figure 2) [Landis and Coombs, 1967; Bradshaw, 1993; Kimbrough et al., 1993]. The 450 km ...
Reconciling the geological history of western Turkey with plate
... western Turkey. Plate circuits show that since 90 Ma, ~1400 km of Africa–Europe convergence occurred, of which ~700 km since 50 Ma and ~450 km since 35 Ma. Seismic tomography shows that the African slab under western Turkey is decoupled from the African Plate. This detached slab is a single, coheren ...
... western Turkey. Plate circuits show that since 90 Ma, ~1400 km of Africa–Europe convergence occurred, of which ~700 km since 50 Ma and ~450 km since 35 Ma. Seismic tomography shows that the African slab under western Turkey is decoupled from the African Plate. This detached slab is a single, coheren ...
29. Sr-, Nd-, AND Pb-ISOTOPIC COMPOSITION OF VOLCANIC
... The Lower and Middle Series volcanic rocks at Site 917 show clear indications of contamination of the magmas with continental crust (Larsen, Saunders, Clift, et al., 1994; Fitton et al., this volume). Variation of incompatible-element ratios with SiO2 content cannot be explained by differentiation o ...
... The Lower and Middle Series volcanic rocks at Site 917 show clear indications of contamination of the magmas with continental crust (Larsen, Saunders, Clift, et al., 1994; Fitton et al., this volume). Variation of incompatible-element ratios with SiO2 content cannot be explained by differentiation o ...
Seismic view on the svalbard passive continental margin
... The Moho discontinuity dips down to 28 km beneath the continental part of the 99200 (northernmost profile) and K1 profiles, and down to maximum 32 km beneath the other profiles. The high P-wave velocity below the Moho interface increases generally up to 8.2 km/s, reaching maximal 8.6 km/s beneath th ...
... The Moho discontinuity dips down to 28 km beneath the continental part of the 99200 (northernmost profile) and K1 profiles, and down to maximum 32 km beneath the other profiles. The high P-wave velocity below the Moho interface increases generally up to 8.2 km/s, reaching maximal 8.6 km/s beneath th ...
Crustal structure of the Hatton and the conjugate east Greenland
... structure of the Hatton flank of the rift has a narrow continent-ocean transition (COT) only 40 km wide, with high velocities (6.9 – 7.3 km/s) in the lower crust intermediate between those of the continental Hatton Bank on one side and the oldest oceanic crust on the other. The high velocities are ...
... structure of the Hatton flank of the rift has a narrow continent-ocean transition (COT) only 40 km wide, with high velocities (6.9 – 7.3 km/s) in the lower crust intermediate between those of the continental Hatton Bank on one side and the oldest oceanic crust on the other. The high velocities are ...
Submarine Silicic Volcanism Niyati G. Kalangutkar* and
... parent magma and by crustal anatexis. Several evidences show the origin of some rhyolitic and andesitic magma to be related due to similar tectonic settings. Fractional crystallisation: This process produces a series of residual liquids of variable compositions as compared to their parental magmas a ...
... parent magma and by crustal anatexis. Several evidences show the origin of some rhyolitic and andesitic magma to be related due to similar tectonic settings. Fractional crystallisation: This process produces a series of residual liquids of variable compositions as compared to their parental magmas a ...
Kerguelen Hotspot Magma Output since 130 Ma
... another consisting of a single, but dismembered plume source. ...
... another consisting of a single, but dismembered plume source. ...
Fig. 1
... such as the Ethiopia–Kenya Broadband Seismic Experiment (EKBSE; e.g., Benoit et al., 2006) and the Ethiopia Afar Geoscientific Lithospheric Experiment (EAGLE; e.g., Bastow et al., 2011) have facilitated increasingly high resolution imaging of the Ethiopian mantle. Seismic tomographic studies on the g ...
... such as the Ethiopia–Kenya Broadband Seismic Experiment (EKBSE; e.g., Benoit et al., 2006) and the Ethiopia Afar Geoscientific Lithospheric Experiment (EAGLE; e.g., Bastow et al., 2011) have facilitated increasingly high resolution imaging of the Ethiopian mantle. Seismic tomographic studies on the g ...
Receiver function images of the Hellenic subduction zone and
... (hereafter referred to as slab), we separately show the stacked PRFs obtained from the western and eastern parts of the Aegean. For the western part we took stations along profiles 1–3 and for the eastern part those along profiles 4–7 (see Fig. 1). Figure 3 illustrates the stacked PRF traces obtaine ...
... (hereafter referred to as slab), we separately show the stacked PRFs obtained from the western and eastern parts of the Aegean. For the western part we took stations along profiles 1–3 and for the eastern part those along profiles 4–7 (see Fig. 1). Figure 3 illustrates the stacked PRF traces obtaine ...
Simultaneous thermal diffusivity and thermal conductivity
... A one-dimensional transient (pulse) method for thermophysical property measurements has been applied to small samples of mantle materials in a uniaxial split-sphere high-pressure apparatus. Thermal diffusivity and thermal conductivity of fused silica and garnet have been measured. At pressures up to ...
... A one-dimensional transient (pulse) method for thermophysical property measurements has been applied to small samples of mantle materials in a uniaxial split-sphere high-pressure apparatus. Thermal diffusivity and thermal conductivity of fused silica and garnet have been measured. At pressures up to ...
Crustal thickness anomalies in the North Atlantic Ocean Tingting Wang
... Madeira (<4%), and New England–Great Meteor Seamount chain (2%), all of which appear to be associated with hot spots. Hot spot–related crustal thickening is largely intermittent, suggesting that melt production is episodic on time scales of tens of millions of years. Thickened crust shows both symme ...
... Madeira (<4%), and New England–Great Meteor Seamount chain (2%), all of which appear to be associated with hot spots. Hot spot–related crustal thickening is largely intermittent, suggesting that melt production is episodic on time scales of tens of millions of years. Thickened crust shows both symme ...
Late-orogenic heating during exhumation: Alpine PTt trajectories
... detachment or breakoff of a subducting slab, and (2) the presence of a wedge of accreted radiogenic material. Numerical models show that both mechanisms are capable of producing significant heating during orogeny. Heating by slab detachment is fast and transient (more than 100‡C in up to 10 million ...
... detachment or breakoff of a subducting slab, and (2) the presence of a wedge of accreted radiogenic material. Numerical models show that both mechanisms are capable of producing significant heating during orogeny. Heating by slab detachment is fast and transient (more than 100‡C in up to 10 million ...
Craton stability and longevity
... convecting mantle for billions of years. Lenardic et al. (2003) proposed that a thick chemically distinct root with more than twice the thickness of typical oceanic lithosphere is required for long term craton stability even if a very viscous cratonic root (1000 times more viscous) is employed. They ...
... convecting mantle for billions of years. Lenardic et al. (2003) proposed that a thick chemically distinct root with more than twice the thickness of typical oceanic lithosphere is required for long term craton stability even if a very viscous cratonic root (1000 times more viscous) is employed. They ...
Review Sheet - School of Ocean and Earth Science and Technology
... Understand the origin of oceanic lithosphere including the role of oceanic ridges and the mechanism of seafloor spreading. Know the structure and geologic characteristics of oceanic crust. Generally know how continental rifting occurs and how ocean basins evolve. Know how subduction relates to the d ...
... Understand the origin of oceanic lithosphere including the role of oceanic ridges and the mechanism of seafloor spreading. Know the structure and geologic characteristics of oceanic crust. Generally know how continental rifting occurs and how ocean basins evolve. Know how subduction relates to the d ...
Simple Models of Diffuse Extension and the Pre
... The s implest model which has been suggesled for d iffuse extension and the s ubseque nt evolution of the extended arel-l is tbe '·stretc hins· · or "atte nualion " model proposed by McKenzie (1978). This model s tarts with fi unit le ngth of lithos phere of th ic kness t with a crust of thîckness t ...
... The s implest model which has been suggesled for d iffuse extension and the s ubseque nt evolution of the extended arel-l is tbe '·stretc hins· · or "atte nualion " model proposed by McKenzie (1978). This model s tarts with fi unit le ngth of lithos phere of th ic kness t with a crust of thîckness t ...
reconnaissance field study of the sarmiento ophiolite with emphasis
... secondary chlorite in the sense of S1 (sample ST02-03). Accessory minerals are titanite, epidote and opaques minerals. Although the original texture of these rocks is partly oblitered due to the dynamic recristallization (deformation lamellaes and undolse extintion in quartz, strain shadows and domi ...
... secondary chlorite in the sense of S1 (sample ST02-03). Accessory minerals are titanite, epidote and opaques minerals. Although the original texture of these rocks is partly oblitered due to the dynamic recristallization (deformation lamellaes and undolse extintion in quartz, strain shadows and domi ...
This is the title of an example SEG abstract using Microsoft
... features that influence groundwater flow in alluvium and underlying volcanic rock aquifers. Although the permeability distribution and the role of faulting on fluid flow are poorly constrained at this site, water table offsets greater than 10 meters are identified on seismic images (Figure 2). These ...
... features that influence groundwater flow in alluvium and underlying volcanic rock aquifers. Although the permeability distribution and the role of faulting on fluid flow are poorly constrained at this site, water table offsets greater than 10 meters are identified on seismic images (Figure 2). These ...
Thermal, Density, Seismological, and Rheological Structure of the
... This thesis presents a first-of-its-kind combined geophysical-petrological methodology to study the thermal, compositional, density, rheological, and seismological structure of different lithospheric domains. The methodology is incorporated in a finite-element code (LitMod) that solves simultaneousl ...
... This thesis presents a first-of-its-kind combined geophysical-petrological methodology to study the thermal, compositional, density, rheological, and seismological structure of different lithospheric domains. The methodology is incorporated in a finite-element code (LitMod) that solves simultaneousl ...
Antigorite Peridotite, Metaserpentinite, and other
... formed during a sharp temperature increase caused by intrusion of the magma that triggered the eruption. Histories of lawsonite eclogite, garnetite, and other inclusions in SUM diatremes have been interpreted to provide context: some are from the lithospheric part of the mantle wedge, hydrated near ...
... formed during a sharp temperature increase caused by intrusion of the magma that triggered the eruption. Histories of lawsonite eclogite, garnetite, and other inclusions in SUM diatremes have been interpreted to provide context: some are from the lithospheric part of the mantle wedge, hydrated near ...
Mantle plume
A mantle plume is a mechanism proposed in 1971 to explain volcanic regions of the earth that were not thought to be explicable by the then-new theory of plate tectonics. Some such volcanic regions lie far from tectonic plate boundaries, for example, Hawaii. Others represent unusually large-volume volcanism, whether on plate boundaries, e.g. Iceland, or basalt floods such as the Deccan or Siberian traps.A mantle plume is posited to exist where hot rock nucleates at the core-mantle boundary and rises through the Earth's mantle becoming a diapir in the Earth's crust. The currently active volcanic centers are known as ""hot spots"". In particular, the concept that mantle plumes are fixed relative to one another, and anchored at the core-mantle boundary, was thought to provide a natural explanation for the time-progressive chains of older volcanoes seen extending out from some such hot spots, such as the Hawaiian–Emperor seamount chain.The hypothesis of mantle plumes from depth is not universally accepted as explaining all such volcanism. It has required progressive hypothesis-elaboration leading to variant propositions such as mini-plumes and pulsing plumes. Another hypothesis for unusual volcanic regions is the ""Plate model"". This proposes shallower, passive leakage of magma from the mantle onto the Earth's surface where extension of the lithosphere permits it, attributing most volcanism to plate tectonic processes, with volcanoes far from plate boundaries resulting from intraplate extension.