Gravity modeling of the lithosphere in the Calatrava
... The origin of the intraplate volcanism in the Calatrava Volcanic Province (CVP) is controversial. On the basis of its geochemical signature, it has been ascribed to an “aborted” rift, implying lithospheric thinning. However, the volcanism occurred during the generalized Cenozoic NW−SE-oriented compr ...
... The origin of the intraplate volcanism in the Calatrava Volcanic Province (CVP) is controversial. On the basis of its geochemical signature, it has been ascribed to an “aborted” rift, implying lithospheric thinning. However, the volcanism occurred during the generalized Cenozoic NW−SE-oriented compr ...
Mid-Ocean Ridges: Mantle Convection and Formation
... and melt production rate are proportional to spreading rate, then, all else being equal, this situation explains the invariance of crustal thickness with spreading rate. On the other hand, all else is not likely to be equal: slower spreading tends to lead to a thicker lithospheric boundary layer, a ...
... and melt production rate are proportional to spreading rate, then, all else being equal, this situation explains the invariance of crustal thickness with spreading rate. On the other hand, all else is not likely to be equal: slower spreading tends to lead to a thicker lithospheric boundary layer, a ...
Isostasy, flexure, and dynamic topography
... structure in various tectonic environments can be deduced in a way that missing parameters can be approximated; or does each area behave differently, making generalizations problematic. We contribute to this issue analyzing the Asia–Africa–Arabia–Europe domain following a top-down strategy. We compi ...
... structure in various tectonic environments can be deduced in a way that missing parameters can be approximated; or does each area behave differently, making generalizations problematic. We contribute to this issue analyzing the Asia–Africa–Arabia–Europe domain following a top-down strategy. We compi ...
Transfer of melts in the sub-arc mantle: Insights from high
... bodies at mid-ocean ridges, more detailed structural and geochemical work on ophiolitic massifs has shown that different kind of environments are conserved in these units. Because of their geodynamic settings, fore-arc peridotites (Horokanai, Massif du Sud, Betts Cove, Coastal Range) are the most li ...
... bodies at mid-ocean ridges, more detailed structural and geochemical work on ophiolitic massifs has shown that different kind of environments are conserved in these units. Because of their geodynamic settings, fore-arc peridotites (Horokanai, Massif du Sud, Betts Cove, Coastal Range) are the most li ...
Fulltext - ETH E-Collection
... The Apuseni-Banat-Timok-Srednogorie (ABTS) magmatic arc in southeastern Europe formed as a result of NE-dipping subduction of the Neotethys ocean beneath the European continental margin during the Late Cretaceous. This magmatic arc is associated with some of Europe’s largest porphyry Cu-Au and epith ...
... The Apuseni-Banat-Timok-Srednogorie (ABTS) magmatic arc in southeastern Europe formed as a result of NE-dipping subduction of the Neotethys ocean beneath the European continental margin during the Late Cretaceous. This magmatic arc is associated with some of Europe’s largest porphyry Cu-Au and epith ...
Towards absolute plate motions constrained by lower
... shift of palaeo-longitudes of continental blocks from the inferred palaeo-subduction zone positions of the 28 slab remnants. As an example, we show how the three anchor slabs8,9,11 constrain the plate tectonic reconstruction3,4 (Fig. 2). A depth slice at 1,900 km in the tomographic model7 correspond ...
... shift of palaeo-longitudes of continental blocks from the inferred palaeo-subduction zone positions of the 28 slab remnants. As an example, we show how the three anchor slabs8,9,11 constrain the plate tectonic reconstruction3,4 (Fig. 2). A depth slice at 1,900 km in the tomographic model7 correspond ...
Snake River Plain-Yellowstone Plateau province, Idaho and Wyoming
... toward the east. However, the transgression is not smooth. Rather, the “volcanic front” appears to have shifted eastward in irregular jumps, but these are not well quantified owing to uncertainties in the locations of source areas for many of the dated rocks (especially ash-flow tuffs). Despite thes ...
... toward the east. However, the transgression is not smooth. Rather, the “volcanic front” appears to have shifted eastward in irregular jumps, but these are not well quantified owing to uncertainties in the locations of source areas for many of the dated rocks (especially ash-flow tuffs). Despite thes ...
2D finite element modeling
... theory of plate tectonics. One of the fundamental postulates of plate tectonics is that the surface plates constituting the lithosphere do not deform significantly on geological time scales. Bott (+33*) suggested that the uppermost ,* km of the continental crust was elastic, representing the strong a ...
... theory of plate tectonics. One of the fundamental postulates of plate tectonics is that the surface plates constituting the lithosphere do not deform significantly on geological time scales. Bott (+33*) suggested that the uppermost ,* km of the continental crust was elastic, representing the strong a ...
Metamorphic reworking of a high - Lamont
... of ocean basins as part of the Wilson Cycle (Wilson, 1960). Most sutures were assumed to be perpendicular to convergent directions since major dip slip motion is required to form HP rocks. However, many modern compressional terrane boundaries are not perpendicular to convergent directions, but obliq ...
... of ocean basins as part of the Wilson Cycle (Wilson, 1960). Most sutures were assumed to be perpendicular to convergent directions since major dip slip motion is required to form HP rocks. However, many modern compressional terrane boundaries are not perpendicular to convergent directions, but obliq ...
pdf file - University of Victoria
... Lower crust flow has previously been concluded for several areas of tectonically thickened orogenic crust. The most studied currently active case is the Tibet high plateau and its flanks (e.g., Clark and Royden, 2000; Beaumont et al., 2001; 2004; 2006; Godin et al., 2006; Klemperer, 2006; Harris, 20 ...
... Lower crust flow has previously been concluded for several areas of tectonically thickened orogenic crust. The most studied currently active case is the Tibet high plateau and its flanks (e.g., Clark and Royden, 2000; Beaumont et al., 2001; 2004; 2006; Godin et al., 2006; Klemperer, 2006; Harris, 20 ...
ž / Evidence from mantle xenoliths for relatively thin -100
... Garnet peridotite xenoliths in the Quaternary Pali-Aike alkali olivine basalts of southernmost South America are samples of the deeper portion of continental lithosphere formed by accretion along the western margin of Gondwanaland during the Phanerozoic. Core compositions of minerals in garnet perid ...
... Garnet peridotite xenoliths in the Quaternary Pali-Aike alkali olivine basalts of southernmost South America are samples of the deeper portion of continental lithosphere formed by accretion along the western margin of Gondwanaland during the Phanerozoic. Core compositions of minerals in garnet perid ...
bedrock geology of the piedmont of delaware and adjacent
... This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allow ...
... This report accompanies a new map that revises the original bedrock geologic maps of the Delaware Piedmont compiled by Woodruff and Thompson and published by the Delaware Geological Survey (DGS) in 1972 and 1975. Combined detailed mapping, petrography, geochemistry, and U-Pb geochronology have allow ...
Becker, T. W. - The University of Texas at Austin
... The long-term stress-state of the lithosphere results from a combination of boundary forces, surface loads and tractions from mantle flow. Here, we have employed a numerical technique which allows for the selfconsistent treatment of the interaction between the lithosphere and mantle and takes into a ...
... The long-term stress-state of the lithosphere results from a combination of boundary forces, surface loads and tractions from mantle flow. Here, we have employed a numerical technique which allows for the selfconsistent treatment of the interaction between the lithosphere and mantle and takes into a ...
Ophiolite concept and its evolution
... than any other topic in geology, and the questions and problems raised and resolved during the course of these studies have made significant contributions to the evolution of geological thought over the years. The topic of ophiolites (their definition, tectonic origin, emplacement mechanisms, etc.) ...
... than any other topic in geology, and the questions and problems raised and resolved during the course of these studies have made significant contributions to the evolution of geological thought over the years. The topic of ophiolites (their definition, tectonic origin, emplacement mechanisms, etc.) ...
Thermal Structure due to Solid-State Flow in the Mantle
... (e.g., discussion in [Johnson and Plank, 1999]). Thus, relatively small changes in thermal models, which make them consistent with PT constraints from the lower crust and uppermost mantle, might also lead to a resolution of the apparent paradox in which geochemistry suggests partial melting of subdu ...
... (e.g., discussion in [Johnson and Plank, 1999]). Thus, relatively small changes in thermal models, which make them consistent with PT constraints from the lower crust and uppermost mantle, might also lead to a resolution of the apparent paradox in which geochemistry suggests partial melting of subdu ...
Chapter 21: Metamorphism
... The IUGS-SCMR proposed this definition: Metamorphism is a subsolidus process leading to changes in mineralogy and/or texture (for example grain size) and often in chemical composition in a rock. These changes are due to physical and/or chemical conditions that differ from those normally occurring at ...
... The IUGS-SCMR proposed this definition: Metamorphism is a subsolidus process leading to changes in mineralogy and/or texture (for example grain size) and often in chemical composition in a rock. These changes are due to physical and/or chemical conditions that differ from those normally occurring at ...
IODP Proposal Cover Sheet
... and into the in situ middle crust that may be a nucleus of continental crust. The average continental crust possesses an intermediate composition (~60 wt.% SiO2), which raises the question of how intra-oceanic arcs produce continental crust if the dominant product of mantle wedge melting and a major ...
... and into the in situ middle crust that may be a nucleus of continental crust. The average continental crust possesses an intermediate composition (~60 wt.% SiO2), which raises the question of how intra-oceanic arcs produce continental crust if the dominant product of mantle wedge melting and a major ...
Thermal and metamorphic environment of subduction zone episodic
... ETS occurs. [3] In subduction zones, the subducting plate and the overriding plate experience different thermal and petrologic histories. Mafic oceanic crust and ultramafic uppermost mantle undergo retrograde metamorphism as the oceanic lithosphere cools away from the ridge and variable amounts of h ...
... ETS occurs. [3] In subduction zones, the subducting plate and the overriding plate experience different thermal and petrologic histories. Mafic oceanic crust and ultramafic uppermost mantle undergo retrograde metamorphism as the oceanic lithosphere cools away from the ridge and variable amounts of h ...
Zircon Behaviour in Deeply Subducted Rocks
... We can thus acquire a detailed knowledge of the temperature–pressure–time paths that these extraordinary rocks have experienced. Zircon studies provide evidence that subduction and exhumation act at plate tectonic speeds of 1–3 cm/year. KEYWORDS: zircon, high-pressure metamorphism, trace elements, e ...
... We can thus acquire a detailed knowledge of the temperature–pressure–time paths that these extraordinary rocks have experienced. Zircon studies provide evidence that subduction and exhumation act at plate tectonic speeds of 1–3 cm/year. KEYWORDS: zircon, high-pressure metamorphism, trace elements, e ...
Mechanisms of crustal growth in large igneous
... asthenospheric mantle) because of the contamination of the melts by various crustal lithologies as illustrated by the Scottish Tertiary volcanics (e.g., Dickin et al., 1987, among others). Another approach to discuss the origin of the igneous activity is to establish the pattern of magma flow within ...
... asthenospheric mantle) because of the contamination of the melts by various crustal lithologies as illustrated by the Scottish Tertiary volcanics (e.g., Dickin et al., 1987, among others). Another approach to discuss the origin of the igneous activity is to establish the pattern of magma flow within ...
Tourmaline Isotopes: No Element Left Behind
... (B), an element essential to its crystal structure (Dutrow and Henry 2011; Hawthorne and Dirlam 2011). Boron is a quintessentially crustal element. Its abundance in the mantle is very low, whereas seawater and rocks of the continental crust show relatively high abundances, containing a large fractio ...
... (B), an element essential to its crystal structure (Dutrow and Henry 2011; Hawthorne and Dirlam 2011). Boron is a quintessentially crustal element. Its abundance in the mantle is very low, whereas seawater and rocks of the continental crust show relatively high abundances, containing a large fractio ...
Use of strontium isotope ratios and rare earth elements in apatite
... in bulk chemical concentration, which is clearly not the case in this study. Distribution of trace elements in the bulk sample and of REE in apatite show co-linear relationships for the ' evolved' group of metabentonites (Figs. 3, 4). In addition, lumps of crustal rock would not break down to clay i ...
... in bulk chemical concentration, which is clearly not the case in this study. Distribution of trace elements in the bulk sample and of REE in apatite show co-linear relationships for the ' evolved' group of metabentonites (Figs. 3, 4). In addition, lumps of crustal rock would not break down to clay i ...
Contrasting origins of Cenozoic silicic volcanic rocks from the
... hornblende and olivine occur in a few (Barr 1993). The rhyolitic ignimbrites and lava flows of the Snake River Plain are typically crystal-poor with less than 20% phenocrysts of plagioclase, quartz, Fe–Ti oxides, Fe-rich pyroxenes, and in some sanidine (or anorthoclase). Biotite and hornblende are r ...
... hornblende and olivine occur in a few (Barr 1993). The rhyolitic ignimbrites and lava flows of the Snake River Plain are typically crystal-poor with less than 20% phenocrysts of plagioclase, quartz, Fe–Ti oxides, Fe-rich pyroxenes, and in some sanidine (or anorthoclase). Biotite and hornblende are r ...
Mantle flow through the Northern Cordilleran slab window revealed
... mantle in the Paleogene to anhydrous asthenosphere or veined lithospheric mantle in the Neogene (Carignan et al., 1994; Edwards and Russell, 2000). This wholesale displacement of arc-type mantle is herein viewed as a passive response to the northward motion of the Pacific slab away from the eastward ...
... mantle in the Paleogene to anhydrous asthenosphere or veined lithospheric mantle in the Neogene (Carignan et al., 1994; Edwards and Russell, 2000). This wholesale displacement of arc-type mantle is herein viewed as a passive response to the northward motion of the Pacific slab away from the eastward ...
The global range of subduction zone thermal structures from
... paths overlap petrologic observations and model averages are 100–300 ◦ C colder than average conditions recorded by rocks. Prograde P–T paths similarly indicate warmer subduction than typical models. Both petrologic estimates and models have inherent biases. Petrologic analysis may overestimate temp ...
... paths overlap petrologic observations and model averages are 100–300 ◦ C colder than average conditions recorded by rocks. Prograde P–T paths similarly indicate warmer subduction than typical models. Both petrologic estimates and models have inherent biases. Petrologic analysis may overestimate temp ...
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.