Seismic imaging of a hot upwelling beneath the British Isles
... A limitation with teleseismic tomography is the depth resolution of velocity anomalies. Most ray paths are subvertical, and therefore anomalies tend to become smeared vertically. In order to interpret anomalies we need to determine if they originate in the crust, in the lithospheric mantle, or in th ...
... A limitation with teleseismic tomography is the depth resolution of velocity anomalies. Most ray paths are subvertical, and therefore anomalies tend to become smeared vertically. In order to interpret anomalies we need to determine if they originate in the crust, in the lithospheric mantle, or in th ...
Imaging subduction from the trench to 300 km depth beneath the
... modern central TVZ is the most frequently active and productive silicic volcanic system on Earth, erupting rhyolite at ca. 0.28 m3 s−1 , and available information suggests this has been so for at least the past 0.34 Myr (Wilson et al. 1995). The average heat flux from the central 6000 km2 of the TVZ ...
... modern central TVZ is the most frequently active and productive silicic volcanic system on Earth, erupting rhyolite at ca. 0.28 m3 s−1 , and available information suggests this has been so for at least the past 0.34 Myr (Wilson et al. 1995). The average heat flux from the central 6000 km2 of the TVZ ...
Ductile shear zone and brittle faults in the southwestern slope of
... between them and “the typical granites”. Later Mandev (1942) also mentioned that the granodiorite close to the contact with the Paleozoic rocks was “gneiissified and in places mylonitized”. On the maps of Kouykin and Milanov (1970) and Kouykin et al. (1971) a “zone of cataclasis and mylonitization” ...
... between them and “the typical granites”. Later Mandev (1942) also mentioned that the granodiorite close to the contact with the Paleozoic rocks was “gneiissified and in places mylonitized”. On the maps of Kouykin and Milanov (1970) and Kouykin et al. (1971) a “zone of cataclasis and mylonitization” ...
Experimental Constraints on TTG Petrogenesis: Implications
... partial melting of metamafic rocks to better constrain TTG petrogenesis; the scope of this work is therefore limited to investigating the melting processes from an experimental perspective. It should be kept in mind that other processes (such as fractional crystallization or interaction with pre-exi ...
... partial melting of metamafic rocks to better constrain TTG petrogenesis; the scope of this work is therefore limited to investigating the melting processes from an experimental perspective. It should be kept in mind that other processes (such as fractional crystallization or interaction with pre-exi ...
Georgian Bay Geological Synthesis, Grenville Province: Explanatory
... tectonic zone, forms the structurally lowest part of the Grenville Orogen in central Ontario. Metamorphism, deformation and minor magmatism related to the collision and convergence that formed the Grenville Orogen are recorded in the Central Gneiss Belt during the interval 1160 to 1000 Ma. Essential ...
... tectonic zone, forms the structurally lowest part of the Grenville Orogen in central Ontario. Metamorphism, deformation and minor magmatism related to the collision and convergence that formed the Grenville Orogen are recorded in the Central Gneiss Belt during the interval 1160 to 1000 Ma. Essential ...
Lithium Isotope Variations in Ocean Island
... The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@ oup.com ...
... The Author 2012. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@ oup.com ...
Mantle-derived magmas and magmatic Ni-Cu-(PGE) deposits
... Magmatic Fe-Ni-Cu ± platinum-group element (PGE) sulfide deposits form when mantlederived mafic and ultramafic magmas become saturated in sulfide and segregate immiscible sulfide liquid, commonly following interaction with crustal rocks. Although the metal contents of primary magmas influence ore co ...
... Magmatic Fe-Ni-Cu ± platinum-group element (PGE) sulfide deposits form when mantlederived mafic and ultramafic magmas become saturated in sulfide and segregate immiscible sulfide liquid, commonly following interaction with crustal rocks. Although the metal contents of primary magmas influence ore co ...
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... much of Cretaceous time. Collision of Kohistan with the Karakorum caused a new, north-dipping subduction zone to form on the south side of Kohistan, leading to collision with India in early Tertiary time. Keywords: Himalayas, Pakistan, island arcs, isotopes. ...
... much of Cretaceous time. Collision of Kohistan with the Karakorum caused a new, north-dipping subduction zone to form on the south side of Kohistan, leading to collision with India in early Tertiary time. Keywords: Himalayas, Pakistan, island arcs, isotopes. ...
Constraints on the Lithospheric Structure of Venus from Mechanical
... not greaterthan 25 K km-. Featuresthat exhibit only the smallerscaleof deformationcan be explained by either a lithospherewith a thick crust that overliesa weak mantle or a lithospherewith a strong mantle but with small internal strengthcontrasts.For a broad range of parameters,the modelsrequire not ...
... not greaterthan 25 K km-. Featuresthat exhibit only the smallerscaleof deformationcan be explained by either a lithospherewith a thick crust that overliesa weak mantle or a lithospherewith a strong mantle but with small internal strengthcontrasts.For a broad range of parameters,the modelsrequire not ...
cenozoic structural geology of the central cimarron range, new mexico
... 1) is a southeastward-extending spur of the southern Sangre de Cristo Mountains. The range is bordered on the west by the down-faulted Moreno Valley, on the east by the Raton basin and on the south by the lava-covered Ocate Plateau. Elevations within the Cimarron Range vary from about 7,500 ft (2290 ...
... 1) is a southeastward-extending spur of the southern Sangre de Cristo Mountains. The range is bordered on the west by the down-faulted Moreno Valley, on the east by the Raton basin and on the south by the lava-covered Ocate Plateau. Elevations within the Cimarron Range vary from about 7,500 ft (2290 ...
The Great Basin Altiplano during the middle
... of individual sheets lend further support for a relatively smooth landscape over which the sheets were draped. We conclude that during the middle Cenozoic, especially towards the close of the ignimbrite flareup, this Great Basin area was a relatively flat plateau, and because it was also high in ele ...
... of individual sheets lend further support for a relatively smooth landscape over which the sheets were draped. We conclude that during the middle Cenozoic, especially towards the close of the ignimbrite flareup, this Great Basin area was a relatively flat plateau, and because it was also high in ele ...
The Mings Bight Ophiolite Complex, Newfoundland: Appalachian
... metamorphosed, prior to the development of the ophiolites and overlying mafic sediments and volcanic rocks, probably in Late Cambrian to earliest Ordovician. The ophiolite sequence and conformably overlying sedimentary and volcanic sequence define an overturned synclinal structure with an eastward v ...
... metamorphosed, prior to the development of the ophiolites and overlying mafic sediments and volcanic rocks, probably in Late Cambrian to earliest Ordovician. The ophiolite sequence and conformably overlying sedimentary and volcanic sequence define an overturned synclinal structure with an eastward v ...
The Yellowstone magmatic system from the
... models of the magmatic system for volcanic hazard assessment. often interpreted as a magma reservoir. Several of these studies also image the top of a second The interaction of the North American Plate moving LVB at greater crustal depths (18, 19); however, they usually southwestward across a mantle ...
... models of the magmatic system for volcanic hazard assessment. often interpreted as a magma reservoir. Several of these studies also image the top of a second The interaction of the North American Plate moving LVB at greater crustal depths (18, 19); however, they usually southwestward across a mantle ...
Depth distribution of Moho and tectonic framework in eastern Asian
... discontinuity were mainly collected from the previously published papers. Totally, 1000 data were collected with point intervals of 50100 km. ...
... discontinuity were mainly collected from the previously published papers. Totally, 1000 data were collected with point intervals of 50100 km. ...
Paleozoic–Mesozoic Porphyry Cu(Mo) and Mo(Cu) Deposits within
... other hand, some researchers consider the subduction-metasomatized mantle lithosphere as a possible source of Mo [3]. Copper is generally considered to be derived from the mantle [1,4]. Nevertheless, some researchers suggest a hybridized lower continental crustal source of Cu [5]. Porphyry Cu–Mo dep ...
... other hand, some researchers consider the subduction-metasomatized mantle lithosphere as a possible source of Mo [3]. Copper is generally considered to be derived from the mantle [1,4]. Nevertheless, some researchers suggest a hybridized lower continental crustal source of Cu [5]. Porphyry Cu–Mo dep ...
Precambrian geology of the Sais Quartzite quarry, northeast Socorro
... have been decisive factors in shaping the mineralogical and structural features of the rocks in the Sais quarry. Low-grade metamorphism of arenaceous and argillaceous sediments has fornled the quartzites and schists of the Precambrian sequence. The north-northeast-trending lineation, with its shallo ...
... have been decisive factors in shaping the mineralogical and structural features of the rocks in the Sais quarry. Low-grade metamorphism of arenaceous and argillaceous sediments has fornled the quartzites and schists of the Precambrian sequence. The north-northeast-trending lineation, with its shallo ...
6. APPLICATION OF PHOTOINTERPRETATION TO GEOLOGY Two
... On the basis of dip amount of flanks or limbs, folds are classified into three groups, namely gentle folds, medium folds and steep folds. a. Gentle folds. The dip amount of the limbs range from 2 to about 10 degrees. Folds in this range have long gentle dipslopes. Gentle folding is of great importan ...
... On the basis of dip amount of flanks or limbs, folds are classified into three groups, namely gentle folds, medium folds and steep folds. a. Gentle folds. The dip amount of the limbs range from 2 to about 10 degrees. Folds in this range have long gentle dipslopes. Gentle folding is of great importan ...
Distribution of potassium feldspar polymorphs
... the alkali feldspars show rather limited variation and are never entirely microcline. The majority of rocks give K-feldspar reflections of types I and 2a. Although many of these type 2a reflections are fairly sharp I3I reflections, diffuse microcline-type cross-hatched twinning can always be seen in ...
... the alkali feldspars show rather limited variation and are never entirely microcline. The majority of rocks give K-feldspar reflections of types I and 2a. Although many of these type 2a reflections are fairly sharp I3I reflections, diffuse microcline-type cross-hatched twinning can always be seen in ...
The geology of the Váddás area, Troms
... Lindahl, I., Stevens, B.P.J. & Zwaan K.B. 2005: The geology of the Váddás area, Troms: a key to our understanding of the Upper Allochthon in the Caledonides of northern Norway. Norges geologiske undersøkelse Bulletin 445, 5–43. The Váddás area in the North Norwegian Caledonides is underlain by the ¢ ...
... Lindahl, I., Stevens, B.P.J. & Zwaan K.B. 2005: The geology of the Váddás area, Troms: a key to our understanding of the Upper Allochthon in the Caledonides of northern Norway. Norges geologiske undersøkelse Bulletin 445, 5–43. The Váddás area in the North Norwegian Caledonides is underlain by the ¢ ...
Chapter 21: Metamorphism
... • Coombs (1961) also proposed hydrothermal metamorphism, caused by hot H2O-rich fluids and usually involving metasomatism • Difficult type of metamorphism to constrain, since hydrothermal effects often play some role in most of the other types of metamorphism ...
... • Coombs (1961) also proposed hydrothermal metamorphism, caused by hot H2O-rich fluids and usually involving metasomatism • Difficult type of metamorphism to constrain, since hydrothermal effects often play some role in most of the other types of metamorphism ...
Baltica in the Cryogenian, 850–630 Ma
... Baltica’s northeastern and eastern regions document episodic intracratonic rifting throughout the Mesoproterozoic, followed by pericontinental passive margin deposition throughout the Cryogenian. In the northeast platformal and deeper-water basin deposits are preserved, whereas the eastern region wa ...
... Baltica’s northeastern and eastern regions document episodic intracratonic rifting throughout the Mesoproterozoic, followed by pericontinental passive margin deposition throughout the Cryogenian. In the northeast platformal and deeper-water basin deposits are preserved, whereas the eastern region wa ...
Perspectives on the origin of plagiogranite in ophiolites from oxygen
... and Coogan, 2002; Stakes and Taylor, 1992). While plagiogranite yields insights into a myriad of processes in modern and ancient settings, their petrogenesis has been the subject of much debate. Most early interpretations of oceanic plagiogranite regarded them as the products of fractional crystalli ...
... and Coogan, 2002; Stakes and Taylor, 1992). While plagiogranite yields insights into a myriad of processes in modern and ancient settings, their petrogenesis has been the subject of much debate. Most early interpretations of oceanic plagiogranite regarded them as the products of fractional crystalli ...
Karson, J.A., and Lawrence, R.M., 1997. Tectonic setting of
... median valley wall of the Mid-Atlantic Ridge just south of the Kane Transform in the MARK area. Serpentinites extend southward from extensive exposures of gabbroic rocks near the Kane Transform. The belt crops out along approximately half the length of a well-defined ridge segment parallel to a prom ...
... median valley wall of the Mid-Atlantic Ridge just south of the Kane Transform in the MARK area. Serpentinites extend southward from extensive exposures of gabbroic rocks near the Kane Transform. The belt crops out along approximately half the length of a well-defined ridge segment parallel to a prom ...
Thrusting, Active Back Thrusting and Tectonic Wedging: An Example
... The Surghar Range is the easternmost extension of the Trans-Indus Salt ranges of North Pakistan that appears as an arcuate mountain belt. The range follows in general an east-west structural trend while bordering the southern Kohat Plateau and switches to north-south trend along the eastern flank of ...
... The Surghar Range is the easternmost extension of the Trans-Indus Salt ranges of North Pakistan that appears as an arcuate mountain belt. The range follows in general an east-west structural trend while bordering the southern Kohat Plateau and switches to north-south trend along the eastern flank of ...
Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario
... platinum group elements (PGE) occur as sulphide concentrations associated with a variety of mafic and ultramafic magmatic rocks (Eckstrand et al., 2004; Naldrett, 2004). The magmas originate in the upper mantle and contain small amounts of nickel, copper, PGE, and variable but minor amounts of S (th ...
... platinum group elements (PGE) occur as sulphide concentrations associated with a variety of mafic and ultramafic magmatic rocks (Eckstrand et al., 2004; Naldrett, 2004). The magmas originate in the upper mantle and contain small amounts of nickel, copper, PGE, and variable but minor amounts of S (th ...
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.