EPSL94HokeHelium3Alt.. - University of Colorado Boulder
... helium production in the crust. Studies of the regional groundwater regime suggest that the wide zone of elevated 3 H e / 4 H e values away from the active volcanic arc is unlikely to be caused by lateral and shallow transport of magmatic helium and there is no evidence for significant crustal sourc ...
... helium production in the crust. Studies of the regional groundwater regime suggest that the wide zone of elevated 3 H e / 4 H e values away from the active volcanic arc is unlikely to be caused by lateral and shallow transport of magmatic helium and there is no evidence for significant crustal sourc ...
International Journal of Advanced Scientific and Technical Research
... The inimitable characters of the Andaman Islands are the presence of Ophiolitic rock strata which having a North-South orientation and having an extension of around 25 kilometres from Carbin cove to Chidiyattapu. These rocks are existed along with sedimentary formations such as Andaman Flysch and Mi ...
... The inimitable characters of the Andaman Islands are the presence of Ophiolitic rock strata which having a North-South orientation and having an extension of around 25 kilometres from Carbin cove to Chidiyattapu. These rocks are existed along with sedimentary formations such as Andaman Flysch and Mi ...
Upper mantle velocity-temperature conversion and composition
... length by Jaupart et al. [1998] and Mareschal and Jaupart [2004], and we only recapitulate the main points. Variations of Moho heat flow, if they exist, would be due to changes of heat supply at the base of the lithosphere which are smoothed out by horizontal heat diffusion. Through 250-km-thick Ar ...
... length by Jaupart et al. [1998] and Mareschal and Jaupart [2004], and we only recapitulate the main points. Variations of Moho heat flow, if they exist, would be due to changes of heat supply at the base of the lithosphere which are smoothed out by horizontal heat diffusion. Through 250-km-thick Ar ...
Geochemistry of mafic rocks and melt inclusions and their
... of a steady-state magma chamber makes it difficult to form corresponding hydrothermal systems. However, once a hydrothermal system was formed in this setting, it would not be as easily damaged by frequent magma events as those at the fast spreading ridges, and the established stable hydrothermal sys ...
... of a steady-state magma chamber makes it difficult to form corresponding hydrothermal systems. However, once a hydrothermal system was formed in this setting, it would not be as easily damaged by frequent magma events as those at the fast spreading ridges, and the established stable hydrothermal sys ...
Origin of ocean island basalts: A new perspective from petrology
... Lu/176Hf) of the DM along these curves are then constrained at any given time in the last 2.5 Gyr. [8] The significant coupling between radiogenic isotopes and incompatible element abundances and ratios in many OIB suites, seamount lavas, and MORB [e.g., Saunders et al., 1988; Sun and McDonough, 198 ...
... Lu/176Hf) of the DM along these curves are then constrained at any given time in the last 2.5 Gyr. [8] The significant coupling between radiogenic isotopes and incompatible element abundances and ratios in many OIB suites, seamount lavas, and MORB [e.g., Saunders et al., 1988; Sun and McDonough, 198 ...
Planetary Atmospheres and Life
... have a neutral oxidation state, as we will explain in Ch. 8. Of course, Rubey’s model has conceptual difficulties as well, as we now think that Earth was enveloped in an impactdegassed atmosphere throughout the latter part of its formation (see Sec. 6.5 and further discussion below). Other authors d ...
... have a neutral oxidation state, as we will explain in Ch. 8. Of course, Rubey’s model has conceptual difficulties as well, as we now think that Earth was enveloped in an impactdegassed atmosphere throughout the latter part of its formation (see Sec. 6.5 and further discussion below). Other authors d ...
Mechanism and timing of Pb transport from subducted oceanic crust
... New high-precision (double-spike) Pb isotope analyses of lavas from Tafahi and Niuatoputapu, the northernmost islands of the Tonga–Kermadec Island Arc, are used to examine the source of Pb in these samples, and the relative timing of Pb addition from the subducting oceanic crust and subducting sedim ...
... New high-precision (double-spike) Pb isotope analyses of lavas from Tafahi and Niuatoputapu, the northernmost islands of the Tonga–Kermadec Island Arc, are used to examine the source of Pb in these samples, and the relative timing of Pb addition from the subducting oceanic crust and subducting sedim ...
The role of crustal heterogeneity in controlling vertical coupling
... (Mixteco – Oaxaca –Juarez block, MOJB). The comparison of the mechanism of deformation of three different analogue models with the natural prototype explains most of the structures observed around the MOJB. Counterclockwise vertical-axis rotations of pre-existing structures in the western flank of t ...
... (Mixteco – Oaxaca –Juarez block, MOJB). The comparison of the mechanism of deformation of three different analogue models with the natural prototype explains most of the structures observed around the MOJB. Counterclockwise vertical-axis rotations of pre-existing structures in the western flank of t ...
univERsity oF copEnhAGEn
... low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, which define the evolution of individual regions. Clearly, plate boundary ...
... low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, which define the evolution of individual regions. Clearly, plate boundary ...
Moho and magmatic underplating
... low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, which define the evolution of individual regions. Clearly, plate boundary ...
... low average density of the crystalline basement (Arndt, this volume; Hawkesworth et al., this volume). The continental crust is subsequently affected by a variety of tectonic, erosional, depositional and metamorphic processes, which define the evolution of individual regions. Clearly, plate boundary ...
Linking rift propagation barriers to excess magmatism at volcanic
... al., 2013; Brune, 2014). Our model is 1500 km long, 250 km wide, and 150 km deep, comprising laterally homogeneous crust and mantle layers (Fig. 2A). Full extension velocity is 20 mm/yr in the x direction, comparable to the extension rate of the southern South Atlantic rift system (Heine et al., 201 ...
... al., 2013; Brune, 2014). Our model is 1500 km long, 250 km wide, and 150 km deep, comprising laterally homogeneous crust and mantle layers (Fig. 2A). Full extension velocity is 20 mm/yr in the x direction, comparable to the extension rate of the southern South Atlantic rift system (Heine et al., 201 ...
Polyphasal brecciation history revealing the nature and depth of
... This study focuses on two minor outcrops (<4000 m2) of breccias in an Early Silurian, Caledonian granite located at two headlands on the north easternmost part of the island of Frøya, Mid Norway. The Skaget breccia has previously been interpreted as a result of a fluidisation process formed during ...
... This study focuses on two minor outcrops (<4000 m2) of breccias in an Early Silurian, Caledonian granite located at two headlands on the north easternmost part of the island of Frøya, Mid Norway. The Skaget breccia has previously been interpreted as a result of a fluidisation process formed during ...
1 Origin and geodynamic relationships of the Late Miocene to
... plume or plume fingers beneath this region. Instead, we propose that plate tectonic processes ...
... plume or plume fingers beneath this region. Instead, we propose that plate tectonic processes ...
The American Cordillera: Part III, The North American Taphrogen
... the surface velocity. At about 75 Ma deformation starts to affect the Sevier foreland, but Sevier deformation continues well into the Laramide (75-55Ma). During this period, note the partitioning of surface velocity between the ENE direction in the Sevier area and the NNE direction in the Laramide a ...
... the surface velocity. At about 75 Ma deformation starts to affect the Sevier foreland, but Sevier deformation continues well into the Laramide (75-55Ma). During this period, note the partitioning of surface velocity between the ENE direction in the Sevier area and the NNE direction in the Laramide a ...
7 Volcano-tectonic Interactions in Kyushu and Implications for Future
... trenchward direction. Zones of extensional faulting are likely to follow the arc migration, as zones of deformation continue to exploit areas of the crust weakened by magmatism. Moreover, continued rollback of the Philippine Sea slab and possible tectonic rotation of the Kyushu forearc will change t ...
... trenchward direction. Zones of extensional faulting are likely to follow the arc migration, as zones of deformation continue to exploit areas of the crust weakened by magmatism. Moreover, continued rollback of the Philippine Sea slab and possible tectonic rotation of the Kyushu forearc will change t ...
Major Gold Deposits and Belts of the North and South American
... American Cordillera reveals the existence of 22 discrete belts in addition to five major isolated deposits, most formed over the last 150 m.y. The gold concentrations are attributed to eight widely recognized deposit types, of which porphyry, sediment-hosted, and high-sulfidation epithermal are econ ...
... American Cordillera reveals the existence of 22 discrete belts in addition to five major isolated deposits, most formed over the last 150 m.y. The gold concentrations are attributed to eight widely recognized deposit types, of which porphyry, sediment-hosted, and high-sulfidation epithermal are econ ...
the orivesi granite batholith, southern central finland
... diffuse internal contacts. They occupy the northern part of the study area and large areas further north. They contain scattered megacrysts of potassium feldspar and abundant mafic inclusions, which are found all over the area. Henceforth we collectively call these rocks granodiorites. Along the wes ...
... diffuse internal contacts. They occupy the northern part of the study area and large areas further north. They contain scattered megacrysts of potassium feldspar and abundant mafic inclusions, which are found all over the area. Henceforth we collectively call these rocks granodiorites. Along the wes ...
13 Oxygen Isotopes in Zircon - University of Wisconsin
... A relatively new and very promising approach to zircon separation is the Electric Pulse Disintegration (EPD), which uses spark discharges of >100 kV to disaggregate a rock, largely along grain boundaries (Rudashevsky et al. 1995, Saint-Eidukat and Weiblen 1996). This technique can preserve delicate ...
... A relatively new and very promising approach to zircon separation is the Electric Pulse Disintegration (EPD), which uses spark discharges of >100 kV to disaggregate a rock, largely along grain boundaries (Rudashevsky et al. 1995, Saint-Eidukat and Weiblen 1996). This technique can preserve delicate ...
Neogene stratigraphy and structure of the Ojo Caliente
... by gently southeast-dipping Neogene sandstone, conglomerate and intercalated volcanics that fill the basin and are cut by northeast-trending Pliocene and Quaternary(?) faults. The basin is one of several north-trending, en-echelon structural depressions of late Cenozoic age that form the Rio Grande ...
... by gently southeast-dipping Neogene sandstone, conglomerate and intercalated volcanics that fill the basin and are cut by northeast-trending Pliocene and Quaternary(?) faults. The basin is one of several north-trending, en-echelon structural depressions of late Cenozoic age that form the Rio Grande ...
Seismic view on the svalbard passive continental margin
... The evolution of the North Atlantic Ocean can be divided into two main phases. The continental break-up occurred and sea floor spreading started along the Reykjanes, Aegir, and Mohns Ridges (Talwani and Eldholm 1977) during the first phase in the Early Eocene. The shearing along faults between north ...
... The evolution of the North Atlantic Ocean can be divided into two main phases. The continental break-up occurred and sea floor spreading started along the Reykjanes, Aegir, and Mohns Ridges (Talwani and Eldholm 1977) during the first phase in the Early Eocene. The shearing along faults between north ...
Guidebook
... The Kohistan terrane in NE Pakistan (Fig. 3) is regarded as a fossil island arc obducted between the collided Indian and Asian plates (Bard et al. 1980, Tahirkheli et al., 1979). Owing to the admirable quality of exposures, the Kohistan offers an unrivalled opportunity to investigate the structure o ...
... The Kohistan terrane in NE Pakistan (Fig. 3) is regarded as a fossil island arc obducted between the collided Indian and Asian plates (Bard et al. 1980, Tahirkheli et al., 1979). Owing to the admirable quality of exposures, the Kohistan offers an unrivalled opportunity to investigate the structure o ...
Variations in magmatic processes along the East Greenland
... to their distance from the Iceland plume. Holbrook et al. (2001) suggest that a modest margin-wide mantle thermal anomaly was present during break-up (∼56 Ma), which was exhausted by 43 Ma. Active upwelling is proposed for the proximal zone of the plume head, whereas the lateral emplacement of warm ...
... to their distance from the Iceland plume. Holbrook et al. (2001) suggest that a modest margin-wide mantle thermal anomaly was present during break-up (∼56 Ma), which was exhausted by 43 Ma. Active upwelling is proposed for the proximal zone of the plume head, whereas the lateral emplacement of warm ...
A review of geological origins and relationships in the Ballantrae
... derived from each have been preserved and juxtaposed. The environment of volcanism can be established by the trace element content of the basaltic lavas produced (e.g. Pearce & Cann 1973; Pearce & Norry 1979); either an island arc formed above a subduction zone, or an ocean island (producing lavas a ...
... derived from each have been preserved and juxtaposed. The environment of volcanism can be established by the trace element content of the basaltic lavas produced (e.g. Pearce & Cann 1973; Pearce & Norry 1979); either an island arc formed above a subduction zone, or an ocean island (producing lavas a ...
Late Palaeozoic lam pro phyres and as so ci ated mafic subvolcanic
... Lamprophyric magmatism in the Sudetes, in the eastern part of the European Variscides, occurred during a period of post-collisional extension in the Carboniferous. The lamprophyres (minettes, vogesites, spessartites, kersantites) and associated mafic rocks (monzonites, micromonzodiorites) were empla ...
... Lamprophyric magmatism in the Sudetes, in the eastern part of the European Variscides, occurred during a period of post-collisional extension in the Carboniferous. The lamprophyres (minettes, vogesites, spessartites, kersantites) and associated mafic rocks (monzonites, micromonzodiorites) were empla ...
101 - Durham University Community
... The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H2O and CO2 rich incipient melt ...
... The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H2O and CO2 rich incipient melt ...
Baltic Shield
The Baltic Shield (sometimes referred to as the Fennoscandian Shield) is located in Fennoscandia (Norway, Sweden and Finland), northwest Russia and under the Baltic Sea. The Baltic Shield is defined as the exposed Precambrian northwest segment of the East European Craton. It is composed mostly of Archean and Proterozoic gneisses and greenstones which have undergone numerous deformations through tectonic activity (see Geology of Fennoscandia map [1]). The Baltic Shield contains the oldest rocks of the European continent. The lithospheric thickness is about 200-300 km. During the Pleistocene epoch, great continental ice sheets scoured and depressed the shield's surface, leaving a thin covering of glacial material and innumerable lakes and streams. The Baltic Shield is still rebounding today following the melting of the thick glaciers during the Quaternary Period.