The Origins of Plate Tectonics Theory
... fish. For years, geologists struggled to explain how the remains of tiny sea organisms could exist at the top of a mountain range. Into the 1900s, many scientists believed that as Earth cooled after its formation, the planet's surface contracted and wrinkled like the skin of an apple, subjected to t ...
... fish. For years, geologists struggled to explain how the remains of tiny sea organisms could exist at the top of a mountain range. Into the 1900s, many scientists believed that as Earth cooled after its formation, the planet's surface contracted and wrinkled like the skin of an apple, subjected to t ...
macpherson_hall_2001 IBM boninites
... Fig. 2. Plate reconstruction of Southeast Asia and the western Paci¢c at 50 Ma, at the start of the Middle Eocene [28]. The locations of the Izu^Bonin and Mariana arcs are indicated, along with estimated extents of pre-Middle Eocene crust of the Amami^ Oki Daito Province and the Southern sub-basin o ...
... Fig. 2. Plate reconstruction of Southeast Asia and the western Paci¢c at 50 Ma, at the start of the Middle Eocene [28]. The locations of the Izu^Bonin and Mariana arcs are indicated, along with estimated extents of pre-Middle Eocene crust of the Amami^ Oki Daito Province and the Southern sub-basin o ...
A submissão dos trabalhos deverá ser feita até 20 de março de 2011
... least for the most primitive terms (i.e. SiO2 ~ 47 wt.% and MgO ~ 6,0 wt.%) of these mafic magmatic enclaves, the magma source may be related to a mantle origin, and probably an enriched lithospheric mantle to account for their high potassium contents. For a quartz-monzonite example from this shosho ...
... least for the most primitive terms (i.e. SiO2 ~ 47 wt.% and MgO ~ 6,0 wt.%) of these mafic magmatic enclaves, the magma source may be related to a mantle origin, and probably an enriched lithospheric mantle to account for their high potassium contents. For a quartz-monzonite example from this shosho ...
Imaging subduction from the trench to 300 km depth beneath the
... Recent dense deployments of portable digital seismographs have provided excellent control on earthquakes beneath the central North Island of New Zealand. Here we use a subset of the best-recorded earthquakes in an inversion for the 3-D Vp and Vp/Vs structure. The data set includes 39 123 P observati ...
... Recent dense deployments of portable digital seismographs have provided excellent control on earthquakes beneath the central North Island of New Zealand. Here we use a subset of the best-recorded earthquakes in an inversion for the 3-D Vp and Vp/Vs structure. The data set includes 39 123 P observati ...
Offshore Somalia: crustal structure and implications
... and Dhow Ridges; the VLCC Ridge extends perpendicular to the coast (see Figure 2). Smaller positive lineaments can be traced; their orientations correlate with the fracture zones. Other positive features do not appear to follow a trend and may be related to localized basement uplift or crustal thinn ...
... and Dhow Ridges; the VLCC Ridge extends perpendicular to the coast (see Figure 2). Smaller positive lineaments can be traced; their orientations correlate with the fracture zones. Other positive features do not appear to follow a trend and may be related to localized basement uplift or crustal thinn ...
Constraining P-wave velocity variations in the upper mantle beneath
... 410 km discontinuity and may not connect to the remnant of the Neo-Tethys oceanic slab in the lower mantle. Our images suggest that only the southwestern part of the Tibetan plateau is underlain by Indian lithosphere and, thus, that the upper mantle beneath northeastern Tibet is primarily of Asian o ...
... 410 km discontinuity and may not connect to the remnant of the Neo-Tethys oceanic slab in the lower mantle. Our images suggest that only the southwestern part of the Tibetan plateau is underlain by Indian lithosphere and, thus, that the upper mantle beneath northeastern Tibet is primarily of Asian o ...
Planetary Atmospheres and Life
... Urey was aware that methane and ammonia had been discovered in the atmospheres of Jupiter and Saturn, and, through a chain of logic, argued for their presence in Earth’s earliest atmosphere. He reasoned that these gases were present on the giant planets because their gravitational attraction was str ...
... Urey was aware that methane and ammonia had been discovered in the atmospheres of Jupiter and Saturn, and, through a chain of logic, argued for their presence in Earth’s earliest atmosphere. He reasoned that these gases were present on the giant planets because their gravitational attraction was str ...
Lithospheric Removal as aTrigger for Flood
... mafic successions emplaced between longitudes 1058W and 1018W range from 11 to 8 Ma and do not display any clear migration pattern (Fig. 2b; Nieto-Obrego¤n et al., 1981; Moore et al., 1994; Ferrari et al., 2000; Rosas-Elguera et al., 2003), indicating that the ‘flood basalts’ began erupting almost ...
... mafic successions emplaced between longitudes 1058W and 1018W range from 11 to 8 Ma and do not display any clear migration pattern (Fig. 2b; Nieto-Obrego¤n et al., 1981; Moore et al., 1994; Ferrari et al., 2000; Rosas-Elguera et al., 2003), indicating that the ‘flood basalts’ began erupting almost ...
Next Generation Sunshine State Standards Chapter 7
... different landmasses despite the unlikely possibility that their living forms could have crossed the vast ocean presently separating these continents. The classic example is Mesosaurus, an aquatic fish-catching reptile whose fossil remains are found only in black shales of the Permian period (about ...
... different landmasses despite the unlikely possibility that their living forms could have crossed the vast ocean presently separating these continents. The classic example is Mesosaurus, an aquatic fish-catching reptile whose fossil remains are found only in black shales of the Permian period (about ...
Small-scale convection at the edge of the Colorado Plateau
... (Bird, 1984; Beghoul and Barazangi, 1989; Roy et al., 2009), have been suggested to contribute to the plateau’s current elevation. The plateau features a superimposed bowl-shaped topography, where edges are elevated with respect to the interior by ~400 m (Fig. 1A). A large seismic S-wave velocity co ...
... (Bird, 1984; Beghoul and Barazangi, 1989; Roy et al., 2009), have been suggested to contribute to the plateau’s current elevation. The plateau features a superimposed bowl-shaped topography, where edges are elevated with respect to the interior by ~400 m (Fig. 1A). A large seismic S-wave velocity co ...
Research Note How Genuine is the Circum
... United States. Gravity work by G. Thompson (1959) in the latter area suggests that this is a region of extension and somewhat similar to East Africa. In late Mesozoic times, this was a geosynclinal area and this seems strong evidence for a change in the mantle convection pattern in the last 70 milli ...
... United States. Gravity work by G. Thompson (1959) in the latter area suggests that this is a region of extension and somewhat similar to East Africa. In late Mesozoic times, this was a geosynclinal area and this seems strong evidence for a change in the mantle convection pattern in the last 70 milli ...
Chapter 17. The Other Isotopes
... depleted, in terms of Nd/Sm , relative to chondritic or undifferentiated material. The Rb/Sr and Nd/Sm ratios are changed when melt is removed or added or if sediment, crust or seawater is added. With time , the isotope ratios of such components diverge. The isotope ratios of the crust and different ...
... depleted, in terms of Nd/Sm , relative to chondritic or undifferentiated material. The Rb/Sr and Nd/Sm ratios are changed when melt is removed or added or if sediment, crust or seawater is added. With time , the isotope ratios of such components diverge. The isotope ratios of the crust and different ...
Calc-alkaline volcanic rocks in mélange formations from the South
... geochemical features are interpreted as having been strongly influenced by subduction related processes. Volcanics with similar major and minor element contents as well as geochemical characters have been reported in other regions in Central Greece and have been attributed to volcanism which occurre ...
... geochemical features are interpreted as having been strongly influenced by subduction related processes. Volcanics with similar major and minor element contents as well as geochemical characters have been reported in other regions in Central Greece and have been attributed to volcanism which occurre ...
The structure and dynamics of the mantle wedge
... thought to take place by dehydration reactions from the subducting oceanic crust and sediments in a near-continuous fashion to a depth of at least 200 km [2]. However, it is not clear how this water is transported to the volcanic front (e.g., [3]). The water that is liberated to the overlying mantle ...
... thought to take place by dehydration reactions from the subducting oceanic crust and sediments in a near-continuous fashion to a depth of at least 200 km [2]. However, it is not clear how this water is transported to the volcanic front (e.g., [3]). The water that is liberated to the overlying mantle ...
Teleseismic imaging of subaxial flow at midocean ridges: traveltime
... ophiolite sequences commonly show significant alignment of minerals along the palaeo shear direction in their mantle sections; and seismic anisotropy in the upper mantle beneath old ocean crust exhibits a fast propagation direction aligned with palaeo plate motion. The narrow axial zone of surface v ...
... ophiolite sequences commonly show significant alignment of minerals along the palaeo shear direction in their mantle sections; and seismic anisotropy in the upper mantle beneath old ocean crust exhibits a fast propagation direction aligned with palaeo plate motion. The narrow axial zone of surface v ...
G. Heinson, Electromagnetic studies of the lithosphere and
... To obtain velocity anomalies of 5%, an associated thermal anomaly of several hundred degrees is required, with slower velocities in hotter mantle (Lay and Wallace, 1995). The presence of partial melt will reduce the shear-wave rigiditymodulus further. Localised temperature perturbations are likely t ...
... To obtain velocity anomalies of 5%, an associated thermal anomaly of several hundred degrees is required, with slower velocities in hotter mantle (Lay and Wallace, 1995). The presence of partial melt will reduce the shear-wave rigiditymodulus further. Localised temperature perturbations are likely t ...
Continent-Continent Convergent Plate Boundaries
... Chapter 1. Continent-Continent Convergent Plate Boundaries ...
... Chapter 1. Continent-Continent Convergent Plate Boundaries ...
PDF (Chapter 8. Chemical Composition of the Mantle)
... must be rich in LIL but relatively poor in Na and the garnetclinopyroxene-compatible elements (such as Al, Ca, Yb, Lu and Sc). Kimberlitic magmas have the required complementary relationship to MORB, and I adopt them here as the Q component. Peridotites are the main reservoirs for elements such as m ...
... must be rich in LIL but relatively poor in Na and the garnetclinopyroxene-compatible elements (such as Al, Ca, Yb, Lu and Sc). Kimberlitic magmas have the required complementary relationship to MORB, and I adopt them here as the Q component. Peridotites are the main reservoirs for elements such as m ...
Homework Problem Set, Chapters 5 and 6, Week 3
... 2b. The increase in atmospheric CO2 during the Cretaceous has been estimated at 3 to 9 times the present pre-industrial concentration. It has also been estimated that the global average temperatures during this period was between 8 and 14°C higher than today. How would these changes have impacted we ...
... 2b. The increase in atmospheric CO2 during the Cretaceous has been estimated at 3 to 9 times the present pre-industrial concentration. It has also been estimated that the global average temperatures during this period was between 8 and 14°C higher than today. How would these changes have impacted we ...
Receiver Function Deconvolution
... Results from the Colorado Plateau-Rio Grande Rift-Great Plains seismic transect (LA RISTRA) experiment show a pure shear extension mechanism for the Rio Grande rift (RGR) at the lithosphere scale. Receiver function results show crustal thickness ranging from 45 to 50 km beneath both the Colorado Pla ...
... Results from the Colorado Plateau-Rio Grande Rift-Great Plains seismic transect (LA RISTRA) experiment show a pure shear extension mechanism for the Rio Grande rift (RGR) at the lithosphere scale. Receiver function results show crustal thickness ranging from 45 to 50 km beneath both the Colorado Pla ...
Plate tectonics on the terrestrial planets
... the gravitational acceleration, is that on smaller planets a much thicker stratification could be developed as a result of partial melting in hot upwelling mantle, because under reduced gravity and pressure conditions the solidus and liquidus pressures correspond to greater depths. This effect is de ...
... the gravitational acceleration, is that on smaller planets a much thicker stratification could be developed as a result of partial melting in hot upwelling mantle, because under reduced gravity and pressure conditions the solidus and liquidus pressures correspond to greater depths. This effect is de ...
Cenozoic magmatism in the western Ross Embayment:
... back to 48 Ma [Tonarini et al., 1997]. The igneous activity, covering a time span of almost 50 m.y., offers the opportunity to reconstruct the long-term evolution of WARS activity. The geological, chronological and geochemical data, along with geochemical modeling, show that the mantle source of mag ...
... back to 48 Ma [Tonarini et al., 1997]. The igneous activity, covering a time span of almost 50 m.y., offers the opportunity to reconstruct the long-term evolution of WARS activity. The geological, chronological and geochemical data, along with geochemical modeling, show that the mantle source of mag ...
Lithosphere and Asthenosphere
... The definition of the lithosphere is based on how Earth materials behave, so it includes the crust and the uppermost mantle, which are both brittle. Since it is rigid and brittle, when stresses act on the lithosphere, it breaks. This is what we experience as an earthquake. Although we sometimes refe ...
... The definition of the lithosphere is based on how Earth materials behave, so it includes the crust and the uppermost mantle, which are both brittle. Since it is rigid and brittle, when stresses act on the lithosphere, it breaks. This is what we experience as an earthquake. Although we sometimes refe ...
Mantle plume
A mantle plume is a mechanism proposed in 1971 to explain volcanic regions of the earth that were not thought to be explicable by the then-new theory of plate tectonics. Some such volcanic regions lie far from tectonic plate boundaries, for example, Hawaii. Others represent unusually large-volume volcanism, whether on plate boundaries, e.g. Iceland, or basalt floods such as the Deccan or Siberian traps.A mantle plume is posited to exist where hot rock nucleates at the core-mantle boundary and rises through the Earth's mantle becoming a diapir in the Earth's crust. The currently active volcanic centers are known as ""hot spots"". In particular, the concept that mantle plumes are fixed relative to one another, and anchored at the core-mantle boundary, was thought to provide a natural explanation for the time-progressive chains of older volcanoes seen extending out from some such hot spots, such as the Hawaiian–Emperor seamount chain.The hypothesis of mantle plumes from depth is not universally accepted as explaining all such volcanism. It has required progressive hypothesis-elaboration leading to variant propositions such as mini-plumes and pulsing plumes. Another hypothesis for unusual volcanic regions is the ""Plate model"". This proposes shallower, passive leakage of magma from the mantle onto the Earth's surface where extension of the lithosphere permits it, attributing most volcanism to plate tectonic processes, with volcanoes far from plate boundaries resulting from intraplate extension.