isotopic and chemical constraints on the development of
... (Pidgeon & Aftalion 1978, Halliday et al. 1979, Harmon & Halliday 1980). The uncertainty in the exact age does not affect the conclusion that the (8'Sr/8oSr)ris > 0.71. The Hill of Fare granite contrasts with this group of granites in being passively emplaced (M. Munro, pers. comm. 1978), and younge ...
... (Pidgeon & Aftalion 1978, Halliday et al. 1979, Harmon & Halliday 1980). The uncertainty in the exact age does not affect the conclusion that the (8'Sr/8oSr)ris > 0.71. The Hill of Fare granite contrasts with this group of granites in being passively emplaced (M. Munro, pers. comm. 1978), and younge ...
A duplex beneath a major overthrust plate in the Montana disturbed
... that the southern end of the eastern Montana disturbed belt contains a large-scale duplex that formed within Paleozoic and Mesozoic rocks beneath the overlying Precambrian and lower Paleozoic rocks of the Steinbach thrust plate. Rocks within the duplex show two distinct styles of deformation. Paleoz ...
... that the southern end of the eastern Montana disturbed belt contains a large-scale duplex that formed within Paleozoic and Mesozoic rocks beneath the overlying Precambrian and lower Paleozoic rocks of the Steinbach thrust plate. Rocks within the duplex show two distinct styles of deformation. Paleoz ...
- BIROn - Birkbeck Institutional Research Online
... in the Carpathian-Pannonian Region (CPR) during Early Miocene to Recent times, as part of the long-lived Alpine-Carpathian-Dinaridic orogenic system (see Schmid et al. 2008 and references therein). We discuss the geodynamic implications of magmatism in an area where several microplates invaded the C ...
... in the Carpathian-Pannonian Region (CPR) during Early Miocene to Recent times, as part of the long-lived Alpine-Carpathian-Dinaridic orogenic system (see Schmid et al. 2008 and references therein). We discuss the geodynamic implications of magmatism in an area where several microplates invaded the C ...
Metamorphic core complexes
... The lower plate of a metamorphic core complex can be intruded by synkinematic granitoids as one of the main results of decompression. The granitoids may ductilely overprinted dependent on uplift process. The granitoids, especially as sills or sill swarms, are found in the central part of gneiss dome ...
... The lower plate of a metamorphic core complex can be intruded by synkinematic granitoids as one of the main results of decompression. The granitoids may ductilely overprinted dependent on uplift process. The granitoids, especially as sills or sill swarms, are found in the central part of gneiss dome ...
Sibson, R., 1977, Fault rocks and fault mechanisms, Jour. geol. Soc
... o. I-I o per cent (Pshennikov 1965, King 1969), though there have been suggestions that ~ approaches unity for very large events (Brune 197o ). Apart from the wave energy, possible sinks for energy dissipation are essentially the same for seismic as for aseismic faulting. Energy may be expended agai ...
... o. I-I o per cent (Pshennikov 1965, King 1969), though there have been suggestions that ~ approaches unity for very large events (Brune 197o ). Apart from the wave energy, possible sinks for energy dissipation are essentially the same for seismic as for aseismic faulting. Energy may be expended agai ...
Volcanic activity before and after large tectonic earthquakes
... literature include events that took place simultaneously as well as events separated by a considerable delay, thus of seconds, days, months or even years. While historical information on the timing of large earthquakes is often very precise, descriptions of volcanic eruptions or other activity chang ...
... literature include events that took place simultaneously as well as events separated by a considerable delay, thus of seconds, days, months or even years. While historical information on the timing of large earthquakes is often very precise, descriptions of volcanic eruptions or other activity chang ...
Geosphere - Do plumes exist?
... variations in the lithospheric potential energy, which contributes to deviatoric tension within the plate. Although these stress changes are small compared to the extensional strength of the lithosphere, they can facilitate continental breakup (Sandiford and Coblentz, 1994). Buck (2006) found that t ...
... variations in the lithospheric potential energy, which contributes to deviatoric tension within the plate. Although these stress changes are small compared to the extensional strength of the lithosphere, they can facilitate continental breakup (Sandiford and Coblentz, 1994). Buck (2006) found that t ...
Seismic Conceptual Design of Buildings
... (vg), and displacement (dg), with their specific frequency contents. Looking at the example of the linear horizontal ground motion chart of an artificially generated «Valais Quake», it is clear that the dominant frequencies of acceleration are substantially higher than those for velocity and much hi ...
... (vg), and displacement (dg), with their specific frequency contents. Looking at the example of the linear horizontal ground motion chart of an artificially generated «Valais Quake», it is clear that the dominant frequencies of acceleration are substantially higher than those for velocity and much hi ...
Earth as a Planet
... is, the north pole becomes the south pole and the south pole becomes the north pole. Scientists are not sure why this happens. One hypothesis is that the convection that drives the magnetic field becomes chaotic and then reverses itself. Another hypothesis is that an external event, such as an aster ...
... is, the north pole becomes the south pole and the south pole becomes the north pole. Scientists are not sure why this happens. One hypothesis is that the convection that drives the magnetic field becomes chaotic and then reverses itself. Another hypothesis is that an external event, such as an aster ...
Geological Structure and Time-Lapse Studies of CO2 Injection
... as other small-scale CCS projects (e.g. Kikuta et al., 2004; Michael et al., 2010), namely to evaluate and develop methods for CO2 monitoring. Even though the Ketzin project involves only injection of CO2 on a small scale, the methodology being employed is similar to what will be used on a larger sc ...
... as other small-scale CCS projects (e.g. Kikuta et al., 2004; Michael et al., 2010), namely to evaluate and develop methods for CO2 monitoring. Even though the Ketzin project involves only injection of CO2 on a small scale, the methodology being employed is similar to what will be used on a larger sc ...
29. Sr-, Nd-, AND Pb-ISOTOPIC COMPOSITION OF VOLCANIC
... Nd/144Nd and low 87Sr/86Sr. Second, the lower units of the Lower Series (below Unit 73A; Fig. 2) plot along a trend to low 143Nd/ 144Nd at nearly constant 87Sr/86Sr, toward the isotopic composition of average granulite-facies Lewisian gneiss (Fig. 1). And third, some of the Lower Series lavas (LSb o ...
... Nd/144Nd and low 87Sr/86Sr. Second, the lower units of the Lower Series (below Unit 73A; Fig. 2) plot along a trend to low 143Nd/ 144Nd at nearly constant 87Sr/86Sr, toward the isotopic composition of average granulite-facies Lewisian gneiss (Fig. 1). And third, some of the Lower Series lavas (LSb o ...
Constraints on the composition of the Aleutian arc lower crust from
... in the lower crust directly beneath the active arc by receiver functions at stations along the arc (H. A. Janiszewski et al., 2013, submitted). Thus, we favor the upper end of our acceptable range (1.7–1.75). 1.4. Interpretation of VP/VS [11] The new VP/VS results presented here combined with the VP ...
... in the lower crust directly beneath the active arc by receiver functions at stations along the arc (H. A. Janiszewski et al., 2013, submitted). Thus, we favor the upper end of our acceptable range (1.7–1.75). 1.4. Interpretation of VP/VS [11] The new VP/VS results presented here combined with the VP ...
geophysical methods for geothermal resource characterization
... important to note that the resistivity measured is usually called apparent and one needs to interpret it using now readily available software to determine the true resistivity of the formation. It is therefore important to indicate when plotting maps whether it is apparent resistivity or true resist ...
... important to note that the resistivity measured is usually called apparent and one needs to interpret it using now readily available software to determine the true resistivity of the formation. It is therefore important to indicate when plotting maps whether it is apparent resistivity or true resist ...
Upper mantle structure beneath the Galápagos Archipelago from
... of propagation, and w is frequency. We assume that higherorder azimuthal terms (4q terms) are small for Rayleigh waves [Smith and Dahlen, 1973]. The direction of fast propagation is 12 arctan (B2 / B1), and the peak-to-peak amplitude or degree of anisotropy is 2(B21 + B22)1/2 / B0. We invert the fre ...
... of propagation, and w is frequency. We assume that higherorder azimuthal terms (4q terms) are small for Rayleigh waves [Smith and Dahlen, 1973]. The direction of fast propagation is 12 arctan (B2 / B1), and the peak-to-peak amplitude or degree of anisotropy is 2(B21 + B22)1/2 / B0. We invert the fre ...
Geophysical Constraints on Mantle Composition
... hence Vj) for single crystals (Zha et al., 1998a). The second group of acoustic methods, the ultrasonic techniques, require larger samples but can be performed on either single crystals or polycrystalline aggregates. They require experimental measurement (via interferometry) of the travel times of t ...
... hence Vj) for single crystals (Zha et al., 1998a). The second group of acoustic methods, the ultrasonic techniques, require larger samples but can be performed on either single crystals or polycrystalline aggregates. They require experimental measurement (via interferometry) of the travel times of t ...
Toward the reconciliation of seismological and petrological
... by limited information from peridotitic xenoliths away from the ridge. Usually, the xenoliths are associated with oceanic islands, which themselves represent tangible evidence for heterogeneity. Along the mid-ocean ridges the geochemical signatures of erupted mid-ocean-ridge basalts (MORB) provide e ...
... by limited information from peridotitic xenoliths away from the ridge. Usually, the xenoliths are associated with oceanic islands, which themselves represent tangible evidence for heterogeneity. Along the mid-ocean ridges the geochemical signatures of erupted mid-ocean-ridge basalts (MORB) provide e ...
Melt Generation at Very Slow-Spreading Oceanic Ridges
... Methods for determining the percentage of mantle melting from geochemical observations rely primarily on measuring the concentrations of one or more elements in the crustal igneous rocks that are the final product of solidification of the mantle melts. The concentration of an element in a mantle mel ...
... Methods for determining the percentage of mantle melting from geochemical observations rely primarily on measuring the concentrations of one or more elements in the crustal igneous rocks that are the final product of solidification of the mantle melts. The concentration of an element in a mantle mel ...
Earthquakes - cloudfront.net
... not as large. However, major earthquakes with magnitudes of 7.0 or more do happen occasionally. All earthquakes in mainland Australia and Tasmania are intraplate, and occur relatively rarely. Most earthquakes in Australia are caused by the rocks being squeezed or compressed by horizontal forces due ...
... not as large. However, major earthquakes with magnitudes of 7.0 or more do happen occasionally. All earthquakes in mainland Australia and Tasmania are intraplate, and occur relatively rarely. Most earthquakes in Australia are caused by the rocks being squeezed or compressed by horizontal forces due ...
global tectonic cycles Temporal relations between mineral deposits
... it is important to differentiate deposits that have gone through a complete supercontinent cycle from those that have not, and the location of deposits with respect to plate margin processes. Deposits that have yet to go through a supercontinent cycle may be as old as Neoproterozoic. The distributio ...
... it is important to differentiate deposits that have gone through a complete supercontinent cycle from those that have not, and the location of deposits with respect to plate margin processes. Deposits that have yet to go through a supercontinent cycle may be as old as Neoproterozoic. The distributio ...
The crustal structure of the southern Caspian region
... structure whose western boundary is a relatively narrow zone across which the crust thins rapidly (~20 km thinning over a 100 km zone) and whose eastern boundary has a more gradual change in crustal thickness (~20 km thinning over a 400 km zone). The velocity–depth profiles derived from the receiver ...
... structure whose western boundary is a relatively narrow zone across which the crust thins rapidly (~20 km thinning over a 100 km zone) and whose eastern boundary has a more gradual change in crustal thickness (~20 km thinning over a 400 km zone). The velocity–depth profiles derived from the receiver ...
Earthscope
Earthscope is an earth science program using geological and geophysical techniques to explore the structure and evolution of the North American continent and to understand the processes controlling earthquakes and volcanoes. The project has three components: USARRAY, the Plate Boundary Observatory, and the San Andreas Fault Observatory at Depth.The project is funded by the National Science Foundation (NSF), and the data produced is publicly accessible in real-time. Organizations associated with the project include UNAVCO, the Incorporated Research Institutions for Seismology (IRIS), Stanford University, the United States Geological Survey (USGS) and National Aeronautics and Space Administration (NASA). Several international organizations also contribute to the initiative.