How Did Early Earth Become Our Modern World?
... temperatures; direct analysis of Earth rocks that retain a memory of events that occurred in the first 100 Ma of Earth history; and geophysical imaging of present-day structures inside the deep Earth coupled with geodynamic modeling that provides an interpretive framework for the origin, evolution, a ...
... temperatures; direct analysis of Earth rocks that retain a memory of events that occurred in the first 100 Ma of Earth history; and geophysical imaging of present-day structures inside the deep Earth coupled with geodynamic modeling that provides an interpretive framework for the origin, evolution, a ...
OKINAWA TROUGH: ORIGIN OF A BACK
... We have not contoured the anomalies because of gaps in our data distribution, the large diurnal variation (up to 60 gammas at the Lunping Magnetic Observatory, Taiwan) and the large secular variation (about 100 gammas). These variations complicate reduction of data that have been collected over an e ...
... We have not contoured the anomalies because of gaps in our data distribution, the large diurnal variation (up to 60 gammas at the Lunping Magnetic Observatory, Taiwan) and the large secular variation (about 100 gammas). These variations complicate reduction of data that have been collected over an e ...
93. Lee, C. - Squarespace
... at the surface are basalt-andesitic to andesitic and hence have higher Si contents. Endmember hypotheses for the origin of andesites are: (1) direct melting of the mantle at water-saturated conditions, (2) partial re-melting of altered basaltic crust, (3) crystal fractionation of arc basalts in crus ...
... at the surface are basalt-andesitic to andesitic and hence have higher Si contents. Endmember hypotheses for the origin of andesites are: (1) direct melting of the mantle at water-saturated conditions, (2) partial re-melting of altered basaltic crust, (3) crystal fractionation of arc basalts in crus ...
The Kaapvaal craton (South Africa): no evidence for a supercontinental
... relatively small composite granite-gneiss-greenstone (island arc complex) terranes from both N and W, does not support formation of a Neoarchean supercontinent, but may well have been related to a mantle plume which enhanced primary gold sources in the accreted terranes and possibly controlled the t ...
... relatively small composite granite-gneiss-greenstone (island arc complex) terranes from both N and W, does not support formation of a Neoarchean supercontinent, but may well have been related to a mantle plume which enhanced primary gold sources in the accreted terranes and possibly controlled the t ...
A Feasibility Study of Non-Seismic Geophysical
... changed by 30%, the bulk density of the reservoir changes by 1.3% (Figure 5). The 1.3% bulk density change produces an approximate 20 µGal change in Gz (Figure 6). The 10 µGals contour defines the edge of the structure. This signal can be measured using current technologies. A 5-10 µGal and 3.5 µGal ...
... changed by 30%, the bulk density of the reservoir changes by 1.3% (Figure 5). The 1.3% bulk density change produces an approximate 20 µGal change in Gz (Figure 6). The 10 µGals contour defines the edge of the structure. This signal can be measured using current technologies. A 5-10 µGal and 3.5 µGal ...
Reconciling the geological history of western Turkey with plate
... collision and slab break-off. To this end, we compare the west Anatolian geological history with amounts of Africa– Europe convergence calculated from the Atlantic plate circuit, and the seismic tomography images of the west Anatolian mantle structure. Western Turkish geology reflects the convergence ...
... collision and slab break-off. To this end, we compare the west Anatolian geological history with amounts of Africa– Europe convergence calculated from the Atlantic plate circuit, and the seismic tomography images of the west Anatolian mantle structure. Western Turkish geology reflects the convergence ...
Hawaii, Boundary Layers and Ambient
... of D’’ that have been quoted as arguments for it being a plausible geochemical reservoir, such as heterogeneity, anisotropy, possible presence of melt, and a high thermal gradient, also apply to the upper BL. D’’, however, has been assumed to have a higher potential temperature and to ...
... of D’’ that have been quoted as arguments for it being a plausible geochemical reservoir, such as heterogeneity, anisotropy, possible presence of melt, and a high thermal gradient, also apply to the upper BL. D’’, however, has been assumed to have a higher potential temperature and to ...
Equatorial Segment of the Mid-Atlantic Ridge: initial results of the
... bathymetric charts, e.g. the GEBCO maps, reveal the complex topography of the oceans with astounding accuracy, while thanks to the Global Positioning System (GPS), positioning at sea has attained a precision undreamt of only a few years ago. These technological innovations have resulted in the colle ...
... bathymetric charts, e.g. the GEBCO maps, reveal the complex topography of the oceans with astounding accuracy, while thanks to the Global Positioning System (GPS), positioning at sea has attained a precision undreamt of only a few years ago. These technological innovations have resulted in the colle ...
Composition of the depleted mantle
... Previously two stage models have been used to estimate the age and parent-daughter ratio of the MORB source. However, for the U-Th-Pb system it has been shown that a simple two-stage evolution cannot explain both the observed U-Th-Pb concentrations and the Th-Pb isotopic compositions of the basalts ...
... Previously two stage models have been used to estimate the age and parent-daughter ratio of the MORB source. However, for the U-Th-Pb system it has been shown that a simple two-stage evolution cannot explain both the observed U-Th-Pb concentrations and the Th-Pb isotopic compositions of the basalts ...
Origin of Mesoproterozoic A-type granites in Laurentia
... Granitic rocks are commonly used as a means to study chemical evolution of continental crust. In particular, their isotopic compositions reflect the relative contributions of mantle and crustal sources in their genesis. In Laurentia, a distinctive belt of Mesoproterozoic A-type or “anorogenic” grani ...
... Granitic rocks are commonly used as a means to study chemical evolution of continental crust. In particular, their isotopic compositions reflect the relative contributions of mantle and crustal sources in their genesis. In Laurentia, a distinctive belt of Mesoproterozoic A-type or “anorogenic” grani ...
The seismic cycle at subduction thrusts: 2. Dynamic implications of
... absolute stress distribution, a more realistic geometry with different rock assemblages, their phase transitions, and corresponding material properties, and a composite bulk rheology (including off-fault plasticity and viscous deformation). However, in the experimental setup of this study, we use a ...
... absolute stress distribution, a more realistic geometry with different rock assemblages, their phase transitions, and corresponding material properties, and a composite bulk rheology (including off-fault plasticity and viscous deformation). However, in the experimental setup of this study, we use a ...
•Earthquakes and Tectonics •Rupture mechanics and modelling
... Heterogenity in stress drop (depth dependent) relative to stress criticallity (dependent on natural stress and fault geometry and rheology) c Restraining bend ...
... Heterogenity in stress drop (depth dependent) relative to stress criticallity (dependent on natural stress and fault geometry and rheology) c Restraining bend ...
Complex seismic trace analysis and its application to time
... events. Instantaneous frequency traces the change of frequency components and can be used to study low-frequency shadow commonly observed under hydrocarbon reservoirs (Taner, 1977 and 1979). Both instantaneous phase and frequency may change in response to interference. With the aid of instantaneous ...
... events. Instantaneous frequency traces the change of frequency components and can be used to study low-frequency shadow commonly observed under hydrocarbon reservoirs (Taner, 1977 and 1979). Both instantaneous phase and frequency may change in response to interference. With the aid of instantaneous ...
Age and petrogenesis of the Tinn granite, Telemark, South
... along a lead-loss line from a Mid Proterozoic upper intercept to a lower intercept which is poorly defined, but within analytical uncertainty of 0 Ma (Fig. 3a). Several points fall significantly to the left of this line, however, suggesting that some zircons have also been affected by a lead-loss ev ...
... along a lead-loss line from a Mid Proterozoic upper intercept to a lower intercept which is poorly defined, but within analytical uncertainty of 0 Ma (Fig. 3a). Several points fall significantly to the left of this line, however, suggesting that some zircons have also been affected by a lead-loss ev ...
Asymmetric plume-ridge interaction around Iceland: The Kolbeinsey
... plotted as reduced travel time (7 km/s) versus range. Data are band-pass filtered from 3 to 20 Hz and amplified as a function of range. Arrivals are observed out to over 100 km. Note the clear PmP arrivals on most stations. ...
... plotted as reduced travel time (7 km/s) versus range. Data are band-pass filtered from 3 to 20 Hz and amplified as a function of range. Arrivals are observed out to over 100 km. Note the clear PmP arrivals on most stations. ...
Chapter 7. Radiogenic Isotope Geochemistry of the Crust and Oceans
... Earth’s 182W/184W is about 2 epsilon units higher than chondrites. The difference reflects sequestration of W in the Earth’s core (or, more likely, the cores of the planetary embryos that accreted to form the Earth) before 182Hf completely decayed, leaving the silicate Earth and Moon enriched in 182 ...
... Earth’s 182W/184W is about 2 epsilon units higher than chondrites. The difference reflects sequestration of W in the Earth’s core (or, more likely, the cores of the planetary embryos that accreted to form the Earth) before 182Hf completely decayed, leaving the silicate Earth and Moon enriched in 182 ...
Seismic Anisotropy of Subduction Zone Minerals–Contribution of
... physically sound parameter than can be observed by seismology in anisotropic regions of the Earth, whereas the Poisson’s ratio, which is often quoted, is not directly observable and does not correspond to the characteristics of wave propagation in an anisotropic or isotropic medium. We report for th ...
... physically sound parameter than can be observed by seismology in anisotropic regions of the Earth, whereas the Poisson’s ratio, which is often quoted, is not directly observable and does not correspond to the characteristics of wave propagation in an anisotropic or isotropic medium. We report for th ...
North America`s Midcontinent Rift: When Rift Met LIP
... Reverse faulting and uplift Additional crustal thickening ...
... Reverse faulting and uplift Additional crustal thickening ...
High resolution tsunami inversion for 2010 Chile earthquake
... The idea of grid shifting method is that the two-layer unit sources shall be able to capture more detailed information than just one-layer ones. Shifting the unit sources by half grid spacing indicates that the sampling resolution is doubled. Because the size of the unit source is larger than the sa ...
... The idea of grid shifting method is that the two-layer unit sources shall be able to capture more detailed information than just one-layer ones. Shifting the unit sources by half grid spacing indicates that the sampling resolution is doubled. Because the size of the unit source is larger than the sa ...
Effects of active crustal movements on thermal structure in
... and erosion effectively transports heat at depth to shallower parts by advection. If the rates of uplift and erosion are sufficiently large, such a process of heat transportation will strongly affect thermal structure in subduction zones. First, we quantitatively examine the effects of uplift and er ...
... and erosion effectively transports heat at depth to shallower parts by advection. If the rates of uplift and erosion are sufficiently large, such a process of heat transportation will strongly affect thermal structure in subduction zones. First, we quantitatively examine the effects of uplift and er ...
Modeling and Simulation of Vibration Isolation System for Large
... factor (∼ 107 ) at room temperature [10] and good optical property, it is used for the mirror substrates in many interferometric gravitational wave detectors, and also for their suspension fibers in some advanced detectors. The thermal noise can be also reduced by lowering the temperature. Since fuse ...
... factor (∼ 107 ) at room temperature [10] and good optical property, it is used for the mirror substrates in many interferometric gravitational wave detectors, and also for their suspension fibers in some advanced detectors. The thermal noise can be also reduced by lowering the temperature. Since fuse ...
Reply to comment by Hillis et al.(2013)
... velocity analyses to show that the Cleethorpes-1 well was denuded by ∼1.4 km which agreed with Green’s (1989) original fission track estimate of 1.3–1.7. Across the East Midlands Shelf, fission track and sonic velocity estimates of denudation are generally higher than those obtained by inverting sub ...
... velocity analyses to show that the Cleethorpes-1 well was denuded by ∼1.4 km which agreed with Green’s (1989) original fission track estimate of 1.3–1.7. Across the East Midlands Shelf, fission track and sonic velocity estimates of denudation are generally higher than those obtained by inverting sub ...
Differentiation of the continental crust by relamination
... 2003a), loss of these rocks still yielded a mafic arc crust very different from continental crust (DeBari and Sleep, 1991; Greene et al., 2006). This is so because garnet-free mafic rocks that are either density-stable or too viscous to founder remain in the cold, upper and middle crust. Whereas found ...
... 2003a), loss of these rocks still yielded a mafic arc crust very different from continental crust (DeBari and Sleep, 1991; Greene et al., 2006). This is so because garnet-free mafic rocks that are either density-stable or too viscous to founder remain in the cold, upper and middle crust. Whereas found ...
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.