sea-floor spreading
... In the mid-1900’s, scientists realized that the ocean floor had many mountain ranges similar to those on the continents. ...
... In the mid-1900’s, scientists realized that the ocean floor had many mountain ranges similar to those on the continents. ...
Omarini, Ricardo H., Massimo Gasparon, Angelo
... mechanism is the Alto Paraguay Triassic alkaline magmatism at the border of the Rio Apa block. This area was affected by rifting at about 241 Ma, probably induced by counter-clockwise and clockwise movements (north and south, respectively) hinged at about 20° latitude south and taking place during t ...
... mechanism is the Alto Paraguay Triassic alkaline magmatism at the border of the Rio Apa block. This area was affected by rifting at about 241 Ma, probably induced by counter-clockwise and clockwise movements (north and south, respectively) hinged at about 20° latitude south and taking place during t ...
Deformation in the Lower Crust of the San Andreas Fault System in
... area. Reflection lines run offshore of central California show that oceanic crust extends 100 km beneath the North American plate and suggest that imbrication of the lower crust has occurred in discrete zones related to the Hosgri fault system (17), a potential precursor of the SAF. Plate motions ar ...
... area. Reflection lines run offshore of central California show that oceanic crust extends 100 km beneath the North American plate and suggest that imbrication of the lower crust has occurred in discrete zones related to the Hosgri fault system (17), a potential precursor of the SAF. Plate motions ar ...
(2016). A joint local and teleseismic tomography study of
... region surrounding the NMSZ. Interpretations of potential field data and active source reconnaissance seismic refraction and reflection experiments suggest significant crustal heterogeneity beneath the embayment related to a long and complex geological history of rifting, uplift, and subsidence [Mooney ...
... region surrounding the NMSZ. Interpretations of potential field data and active source reconnaissance seismic refraction and reflection experiments suggest significant crustal heterogeneity beneath the embayment related to a long and complex geological history of rifting, uplift, and subsidence [Mooney ...
Deep crustal structure along the Niigata-Kobe Tectonic Zone, Japan:
... and Honkura (2004) detected a deep crustal conductor beneath the volcanic region at the west of the ISTL. These observations may suggest the existence of the magmatic fluids in the lower crust and uppermost mantle under a possible high temperature condition. It is inferred that the low-velocity anom ...
... and Honkura (2004) detected a deep crustal conductor beneath the volcanic region at the west of the ISTL. These observations may suggest the existence of the magmatic fluids in the lower crust and uppermost mantle under a possible high temperature condition. It is inferred that the low-velocity anom ...
Driving mechanism and 3-D circulation of plate tectonics
... trenches, whereas in fact broad, systematic structural belts intervene, and have characteristics that constrain the process of subduction and hence the driving mechanism of plate tectonics. The Sumatra-Java-Banda arc of Indonesia (Fig, 4) has a well-defined and continuous active forearc system. The ...
... trenches, whereas in fact broad, systematic structural belts intervene, and have characteristics that constrain the process of subduction and hence the driving mechanism of plate tectonics. The Sumatra-Java-Banda arc of Indonesia (Fig, 4) has a well-defined and continuous active forearc system. The ...
A Melt Extraction From The Mantle Beneath Mid-Ocean Ridges Peter Kelemen
... s the oceanic plates move apart at midocean ridges, rocks from Earth’s mantle, far below, rise to fill the void, mostly via slow plastic flow. As the rock approaches the top of its journey, however, partial melting occurs, so that the upper 6 kilometers of oceanic crust are composed of melts, which ...
... s the oceanic plates move apart at midocean ridges, rocks from Earth’s mantle, far below, rise to fill the void, mostly via slow plastic flow. As the rock approaches the top of its journey, however, partial melting occurs, so that the upper 6 kilometers of oceanic crust are composed of melts, which ...
A model to explain the various paradoxes associated with mantle
... means and medians well within the MORB range, and from this point of view, they could represent samples drawn from the same population. The 3He content of MORB is generally much higher than in OIB. Because the non-MORB samples are so small, and so heterogeneous in helium content and in the isotopic ...
... means and medians well within the MORB range, and from this point of view, they could represent samples drawn from the same population. The 3He content of MORB is generally much higher than in OIB. Because the non-MORB samples are so small, and so heterogeneous in helium content and in the isotopic ...
Non-plume magmatism and tectonics during the opening of the
... and plutonic cumulate wedge is uniformly large along most of the eastern North American margin ( Fig. 1), as shown by the east coast magnetic anomaly and seismic reflections, and by itself constitutes a major large igneous province ( Kelemen and Holbrook, 1995). Originally, a genetic link was propos ...
... and plutonic cumulate wedge is uniformly large along most of the eastern North American margin ( Fig. 1), as shown by the east coast magnetic anomaly and seismic reflections, and by itself constitutes a major large igneous province ( Kelemen and Holbrook, 1995). Originally, a genetic link was propos ...
Changes in seismic anisotropy shed light on the nature of the
... Seismic body waves also intermittently detect a sharp velocity reduction at similar depths, the Gutenberg (G) discontinuity, which cannot be explained by temperature alone. We compared an anisotropic tomography model with detections of the G to evaluate their context and relation to the lithosphere- ...
... Seismic body waves also intermittently detect a sharp velocity reduction at similar depths, the Gutenberg (G) discontinuity, which cannot be explained by temperature alone. We compared an anisotropic tomography model with detections of the G to evaluate their context and relation to the lithosphere- ...
Document
... Small, spherical, heat-emitting probe could reach depths well in excess of 100 km below the surface of both oceanic and continental crust. Initial penetration of the crust would be very rapid and worthwhile depths in the mantle could be reached in ~35 years. The acoustic signals generated during the ...
... Small, spherical, heat-emitting probe could reach depths well in excess of 100 km below the surface of both oceanic and continental crust. Initial penetration of the crust would be very rapid and worthwhile depths in the mantle could be reached in ~35 years. The acoustic signals generated during the ...
1st Sem (unit I)
... climatology is the science which studies the nature of climate, the causes and interpretation of its spatial variations and its association with the elements of natural environment and human activities. In simple words it is the systematic and regional study of atmospheric conditions i.e. weather an ...
... climatology is the science which studies the nature of climate, the causes and interpretation of its spatial variations and its association with the elements of natural environment and human activities. In simple words it is the systematic and regional study of atmospheric conditions i.e. weather an ...
Theory of Plate Tectonics As you may have discovered, Earth is not
... As you may have discovered, Earth is not just an ordinary planet in the solar system. Much like peeling an onion, Earth’s layers reveal answers to some interesting mysteries that have baffled scientists for years. Earth’s crust, the outer most layer, is not entirely one piece. It is broken into sect ...
... As you may have discovered, Earth is not just an ordinary planet in the solar system. Much like peeling an onion, Earth’s layers reveal answers to some interesting mysteries that have baffled scientists for years. Earth’s crust, the outer most layer, is not entirely one piece. It is broken into sect ...
PLATE TECTONICS
... • When an earthquake occurs, it produces what’s called a seismic wave. • By studying the way these travel through the earth, we can discover things about the layers of the earth and the changes in composition ...
... • When an earthquake occurs, it produces what’s called a seismic wave. • By studying the way these travel through the earth, we can discover things about the layers of the earth and the changes in composition ...
The role of water in connecting past and future episodes of
... water estimated here is likely less dense than dry ringwoodite and could thus be buoyant. The amount of buoyancy is uncertain, with estimates ranging from 0 to 0.6% for the mantle assemblage, depending on the depth (Inoue et al., 2004; Jacobsen et al., 2004). However, the effects of water on the den ...
... water estimated here is likely less dense than dry ringwoodite and could thus be buoyant. The amount of buoyancy is uncertain, with estimates ranging from 0 to 0.6% for the mantle assemblage, depending on the depth (Inoue et al., 2004; Jacobsen et al., 2004). However, the effects of water on the den ...
Supplementary Material Wanless, V. D., M. R. Perfit, E. M. Klein, S
... of the oceanic crust [Hekinian et al., 1993; Coogan, 2007; and Natland and Dick, 2009] and that crystallization is not restricted to the melt lens. The second hypothesis proposes that melts differentiate from primitive high-MgO compositions to more typical MORB compositions (< 9 wt% MgO) in the upp ...
... of the oceanic crust [Hekinian et al., 1993; Coogan, 2007; and Natland and Dick, 2009] and that crystallization is not restricted to the melt lens. The second hypothesis proposes that melts differentiate from primitive high-MgO compositions to more typical MORB compositions (< 9 wt% MgO) in the upp ...
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.