Stratigraphic placement and age of modern humans from Kibish
... from essentially the same level as the hominid, but they and others have questioned the reliability of the age5,6. Omo II was found on the surface at PHS (Paul’s Hominid Site), which Butzer14 mapped about 2.6 km northwest of KHS. A map drawn at the time by Paul Abell (discoverer of Omo II), together ...
... from essentially the same level as the hominid, but they and others have questioned the reliability of the age5,6. Omo II was found on the surface at PHS (Paul’s Hominid Site), which Butzer14 mapped about 2.6 km northwest of KHS. A map drawn at the time by Paul Abell (discoverer of Omo II), together ...
Supercontinent cycles and the distribution of metal
... Caledonian-Appalachian orogen (e.g., Duane and deWit, 1988) or during periods of active rifting (e.g., Sawkins, 1976). Layered intrusions that contain Ni sulfides and PGE mineralization, such as Norilsk (in Siberia) and Insizwa (in Transkei) also formed during the early stages of the breakup of Pang ...
... Caledonian-Appalachian orogen (e.g., Duane and deWit, 1988) or during periods of active rifting (e.g., Sawkins, 1976). Layered intrusions that contain Ni sulfides and PGE mineralization, such as Norilsk (in Siberia) and Insizwa (in Transkei) also formed during the early stages of the breakup of Pang ...
SUPERFAULTS AND PSEUDOTACHYLYTES
... might have more than ten times the displacement distance and more than ten times the heat generation, allowing rocks to melt. The resulting “superquake” would be extraordinary, like none on Earth that humans have witnessed in historic times. The term “pseudotachylyte” (here abbreviated PST) was firs ...
... might have more than ten times the displacement distance and more than ten times the heat generation, allowing rocks to melt. The resulting “superquake” would be extraordinary, like none on Earth that humans have witnessed in historic times. The term “pseudotachylyte” (here abbreviated PST) was firs ...
42. The New England Seamounts
... al., 1977; Duncan and Houghton, 1977, Houghton, 1978). (3) and (4) K-Ar hornblende crystallization ages from Vogel Seamount—site 385 (Houghton et al., this volume). (5) Very uncertain Coniacian-Santonian age from ben¬ thic foraminifers in volcaniclastic sediment above breccia at Site 385. (6) Mid-Ma ...
... al., 1977; Duncan and Houghton, 1977, Houghton, 1978). (3) and (4) K-Ar hornblende crystallization ages from Vogel Seamount—site 385 (Houghton et al., this volume). (5) Very uncertain Coniacian-Santonian age from ben¬ thic foraminifers in volcaniclastic sediment above breccia at Site 385. (6) Mid-Ma ...
Recent tectonics associated with the subduction : collision of the d
... trend NllO", and have amplitude and wavelength characteristics attributable to geomagnetic reversals correlated from south to north with anomalies 21 to 24 (Fig. 5). Weissel et al. (1977, 1982), and Lapouille (1982) have described a similar pattern from the southeastern part of the basin where the a ...
... trend NllO", and have amplitude and wavelength characteristics attributable to geomagnetic reversals correlated from south to north with anomalies 21 to 24 (Fig. 5). Weissel et al. (1977, 1982), and Lapouille (1982) have described a similar pattern from the southeastern part of the basin where the a ...
A trace element perspective on the source of ocean island basalts
... element enriched OIB component in this context. Hofmann and White (1982) were the first advocates for “Recycled Oceanic Crust” (ROC) as the enriched source material for OIB. They proposed that oceanic crust is returned to the mantle during subduction. Eventually, it becomes unstable (at the core-man ...
... element enriched OIB component in this context. Hofmann and White (1982) were the first advocates for “Recycled Oceanic Crust” (ROC) as the enriched source material for OIB. They proposed that oceanic crust is returned to the mantle during subduction. Eventually, it becomes unstable (at the core-man ...
Modeling and Inversion of Dispersion Curves of Surface Waves in
... map, and seismic-resistant design of buildings. The use of surface waves for the characterization of the shallow subsurface involves three steps: a) acquisition of highfrequency broadband seismic surface wave records generated either by active sources or passive ambient noise (microtremors or micros ...
... map, and seismic-resistant design of buildings. The use of surface waves for the characterization of the shallow subsurface involves three steps: a) acquisition of highfrequency broadband seismic surface wave records generated either by active sources or passive ambient noise (microtremors or micros ...
A new look at the Altaids: A superorogenic complex in northern and
... we chose was in harmony with the surrounding units and whether this position satisfied the relative position of any given unit with respect to those from which palaeomagnetic data are available and with the previous and the next reconstructions. This method was critically dependent on choosing an in ...
... we chose was in harmony with the surrounding units and whether this position satisfied the relative position of any given unit with respect to those from which palaeomagnetic data are available and with the previous and the next reconstructions. This method was critically dependent on choosing an in ...
An olivine-free mantle source of Hawaiian shield
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
An olivine-free mantle source of Hawaiian shield basalts
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
... More than 50 per cent of the Earth’s upper mantle consists of olivine and it is generally thought that mantle-derived melts are generated in equilibrium with this mineral. Here, however, we show that the unusually high nickel and silicon contents of most parental Hawaiian magmas are inconsistent wit ...
Latitudinal distribution of earthquakes in the Andes and its peculiarity
... Previous attempts to normalize the number of events by the square of the latitudinal zone were ineffective and physically wrong due to a strong irregularity in the distribution of earthquakes within the latitudinal zones. Taking into account the fact that the earthquakes occur generally along the bo ...
... Previous attempts to normalize the number of events by the square of the latitudinal zone were ineffective and physically wrong due to a strong irregularity in the distribution of earthquakes within the latitudinal zones. Taking into account the fact that the earthquakes occur generally along the bo ...
Trace element and isotope geochemistry of gabbro
... protoliths, (ii) the role of fractional crystallization and crustal assimilation in the igneous differentiation process, (iii) the nature of the mantle source. Trace element and Sr-Nd isotopic analyses have been performed on selected granulite samples, and clinopyroxene and plagioclase cores from un ...
... protoliths, (ii) the role of fractional crystallization and crustal assimilation in the igneous differentiation process, (iii) the nature of the mantle source. Trace element and Sr-Nd isotopic analyses have been performed on selected granulite samples, and clinopyroxene and plagioclase cores from un ...
PDF
... persistent, low-amplitude tremor activity throughout the October 2003 through February 2007 period of monitoring. These signals exhibit either monochromatic or polychromatic spectral characteristics, with a 6 Hz fundamental frequency and up to two harmonics. Individual events cannot be correlated b ...
... persistent, low-amplitude tremor activity throughout the October 2003 through February 2007 period of monitoring. These signals exhibit either monochromatic or polychromatic spectral characteristics, with a 6 Hz fundamental frequency and up to two harmonics. Individual events cannot be correlated b ...
Ophiolites and Their Origins
... and proposed, based on geochemical interpretations, that Ophiolites are the remnants of ancient oceanic crust the Troodos oceanic crust on Cyprus was a product of and upper mantle that were tectonically emplaced into island arc magmatism. This was a revolutionary but controcontinental margins. They ...
... and proposed, based on geochemical interpretations, that Ophiolites are the remnants of ancient oceanic crust the Troodos oceanic crust on Cyprus was a product of and upper mantle that were tectonically emplaced into island arc magmatism. This was a revolutionary but controcontinental margins. They ...
AI04703218222
... In general the most suitable choices in improvement of reinforcement concrete frame against lateral loading is used steel bracing system. The use of steel bracing has potential advantage over other scheme like higher strength and stiffness, economical, occupies less space, adds much less weight to e ...
... In general the most suitable choices in improvement of reinforcement concrete frame against lateral loading is used steel bracing system. The use of steel bracing has potential advantage over other scheme like higher strength and stiffness, economical, occupies less space, adds much less weight to e ...
Kistufell: Primitive Melt from the Iceland Mantle
... to recycled oceanic crust in their mantle source (Lassiter & Hauri, 1998; Sobolev et al., 2000), a similar interpretation is not obvious for Iceland. This is because interaction between North Atlantic N-MORB and local hydrothermally altered crust can produce similar geochemical anomalies in Icelandi ...
... to recycled oceanic crust in their mantle source (Lassiter & Hauri, 1998; Sobolev et al., 2000), a similar interpretation is not obvious for Iceland. This is because interaction between North Atlantic N-MORB and local hydrothermally altered crust can produce similar geochemical anomalies in Icelandi ...
CONSTRAINING PORE PRESSURE
... ray. Here, we can segregate the major three layers within our interval as the following: (1) low impedance, low gamma ray and slow velocity porous sand (reservoir), (2) medium impedance, moderate gamma ray and moderate to high velocity shaley sand, (3) high impedance, moderate to high gamma ray with ...
... ray. Here, we can segregate the major three layers within our interval as the following: (1) low impedance, low gamma ray and slow velocity porous sand (reservoir), (2) medium impedance, moderate gamma ray and moderate to high velocity shaley sand, (3) high impedance, moderate to high gamma ray with ...
Meteorite Impacts as Triggers to Large Igneous Provinces
... volumes. Computer simulations suggest that, in addition to shockinduced melting produced by impact, additional decompression melting of the hot target mantle beneath the crater can produce melt volumes comparable to those found in large igneous provinces (LIPs). The coincidence between the expected ...
... volumes. Computer simulations suggest that, in addition to shockinduced melting produced by impact, additional decompression melting of the hot target mantle beneath the crater can produce melt volumes comparable to those found in large igneous provinces (LIPs). The coincidence between the expected ...
A 3-D geodynamic model of lateral crustal flow
... be ~4.1x106 km3 (Fig. 1). Assuming Airy isostasy and average crust and mantle densities of 2830 - 2870 and 3300 kg m-3, the observed crustal volume added by mountain building is 29 - 31x106 km3. This volume can be compared to that expected assuming a spatial pattern of shortening. Shortening estimat ...
... be ~4.1x106 km3 (Fig. 1). Assuming Airy isostasy and average crust and mantle densities of 2830 - 2870 and 3300 kg m-3, the observed crustal volume added by mountain building is 29 - 31x106 km3. This volume can be compared to that expected assuming a spatial pattern of shortening. Shortening estimat ...
Analysis of the Global Data Set
... area, and in the oceans it was the age of formation of mapped subdivisionsof Larson et al. [1985] (with but the oceaniccrust. The tectonothermalage is typically one exception, the Precambrian; see below), form the based on dates from isotopic systems, for instance, basis of our empirical estimators ...
... area, and in the oceans it was the age of formation of mapped subdivisionsof Larson et al. [1985] (with but the oceaniccrust. The tectonothermalage is typically one exception, the Precambrian; see below), form the based on dates from isotopic systems, for instance, basis of our empirical estimators ...
The role of crustal and mantle sources in the genesis of granitoids of
... range in granite composition by mixing of a MORB-like mantle end-member with melts of the paragneiss. However, Wever et al. (1995) showed that a solution could be achieved by mixing melts of paragneiss with an enriched (i.e. low Ndi, high 87Sr/86Sri) mafic end-member, similar in composition to the ...
... range in granite composition by mixing of a MORB-like mantle end-member with melts of the paragneiss. However, Wever et al. (1995) showed that a solution could be achieved by mixing melts of paragneiss with an enriched (i.e. low Ndi, high 87Sr/86Sri) mafic end-member, similar in composition to the ...
Slide 1
... In exhumed arc sections worldwide, the upper mid-crust is composed dominantly of hornblende-bearing tonalite, quartz diorite, diorite, and gabbro (49-76 wt.% SiO2) whose compositions would correspond to an in situ Vp in the range of 6.0-6.3 km/s. This is in contrast to a more mafic, cumulate lower c ...
... In exhumed arc sections worldwide, the upper mid-crust is composed dominantly of hornblende-bearing tonalite, quartz diorite, diorite, and gabbro (49-76 wt.% SiO2) whose compositions would correspond to an in situ Vp in the range of 6.0-6.3 km/s. This is in contrast to a more mafic, cumulate lower c ...
Exploring Earth: Plate Tectonics
... deep conceptual understanding that is aligned with the standards, key science concepts, and essential features of classroom inquiry (as defined by the National Science Education Standards). In Immersion Units, students learn academic content by working like scientists: making observations, asking qu ...
... deep conceptual understanding that is aligned with the standards, key science concepts, and essential features of classroom inquiry (as defined by the National Science Education Standards). In Immersion Units, students learn academic content by working like scientists: making observations, asking qu ...
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.