Seismic constraints on Ear th`s small-sc
... Despite considerable success in imaging the Earth’s interior, many unanswered questions about the structure and dynamics of the interior of our planet remain. Seismology has to play a major role in answering many of these. The Earth’s core–mantle boundary (CMB) lies almost 3000 km beneath the surfac ...
... Despite considerable success in imaging the Earth’s interior, many unanswered questions about the structure and dynamics of the interior of our planet remain. Seismology has to play a major role in answering many of these. The Earth’s core–mantle boundary (CMB) lies almost 3000 km beneath the surfac ...
IDOE Workshop on Tectonic Patterns and Metallogenesis in East
... eastern Asia,from the Sunda Arc to the Japanese islands,and from the stable shelfof the Gulf of Thailand to the stable shelf bordering northern Australia, provide one of the most significant regions of the earth's surface for the study of present-day tectonic processes and of their effects in the re ...
... eastern Asia,from the Sunda Arc to the Japanese islands,and from the stable shelfof the Gulf of Thailand to the stable shelf bordering northern Australia, provide one of the most significant regions of the earth's surface for the study of present-day tectonic processes and of their effects in the re ...
Alteration of stress field brought about by the occurrence of... M 9.0) w
... The CFF due to the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0) has been investigated assuming several target faults in northeastern Japan. The increased activity of normal-fault earthquakes occurring after the main shock is explained by a large positive CFF of 1–5 MPa prevailing over ...
... The CFF due to the 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0) has been investigated assuming several target faults in northeastern Japan. The increased activity of normal-fault earthquakes occurring after the main shock is explained by a large positive CFF of 1–5 MPa prevailing over ...
Niu, Y., Generation and evolution of basaltic magmas
... explains the occurrences and distributions earthquakes and voluminous volcanic eruptions along plate boundaries: (1) at seafloor spreading centers where two plates pull apart, the ocean crust is being continuously created by volcanism; (2) at convergent boundaries where the oceanic plate returns int ...
... explains the occurrences and distributions earthquakes and voluminous volcanic eruptions along plate boundaries: (1) at seafloor spreading centers where two plates pull apart, the ocean crust is being continuously created by volcanism; (2) at convergent boundaries where the oceanic plate returns int ...
Recycled crust in the Galápagos Plume source at 70 Ma
... 3. Materials and methods The formation of the Caribbean Large Igneous Province (CLIP) began ∼90 Ma with the incipient melting of the Galápagos plume head (Duncan and Hargraves, 1984; Richards et al., 1989; Pindel and Barrett, 1990; Kerr et al., 1996a, 1996b; Hauff et al., 1997, 2000a; Sinton et al., ...
... 3. Materials and methods The formation of the Caribbean Large Igneous Province (CLIP) began ∼90 Ma with the incipient melting of the Galápagos plume head (Duncan and Hargraves, 1984; Richards et al., 1989; Pindel and Barrett, 1990; Kerr et al., 1996a, 1996b; Hauff et al., 1997, 2000a; Sinton et al., ...
Sub-slab mantle flow parallel to the Caribbean plate boundaries
... intermediate crustal thicknesses, high seismicity, large Bouger gravity and magnetic anomalies, late Cenozoic volcanic activity in central Hispaniola, and active oceanic volcanism in the Cayman trough spreading center. In the south, the Caribbean and South American Plates interact in a wide and comp ...
... intermediate crustal thicknesses, high seismicity, large Bouger gravity and magnetic anomalies, late Cenozoic volcanic activity in central Hispaniola, and active oceanic volcanism in the Cayman trough spreading center. In the south, the Caribbean and South American Plates interact in a wide and comp ...
Supercontinent cycles and the distribution of metal
... 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 Pangea (Sawkins, 1990). Because they developed on thick, relatively stable ...
... 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 Pangea (Sawkins, 1990). Because they developed on thick, relatively stable ...
The Yellowstone magmatic system from the mantle
... Imaging the position and size of the entire volcanic plumbing system is also important to constrain magmatic dynamics modeling for further hazard assessment (14). Many local seismic array experiments have been conducted on volcanoes such as Askja, Iceland (15); Axial, Juan de Fuca mid-ocean ridge (1 ...
... Imaging the position and size of the entire volcanic plumbing system is also important to constrain magmatic dynamics modeling for further hazard assessment (14). Many local seismic array experiments have been conducted on volcanoes such as Askja, Iceland (15); Axial, Juan de Fuca mid-ocean ridge (1 ...
Dependence of mid-ocean ridge morphology on spreading rate in
... and a lack of transform faults. In the amagmatic zones, plate separation is accommodated tectonically. On the other end of the spectrum, Naar and Hey (1989) observed that for full spreading rates >145 mm/yr, transform faults are replaced by rotating microplates, propagating rifts or overlapping spre ...
... and a lack of transform faults. In the amagmatic zones, plate separation is accommodated tectonically. On the other end of the spectrum, Naar and Hey (1989) observed that for full spreading rates >145 mm/yr, transform faults are replaced by rotating microplates, propagating rifts or overlapping spre ...
Foundation RESTLESS EARTH v2014
... (4 marks – June 2007) 4 (c) Earthquakes are another example of tectonic activity. Describe the primary and secondary effects of an earthquake. (4 marks – June 2008) 1 (d) Describe how the effects of an earthquake in a richer area of the world are different from the effects of an earthquake in a poor ...
... (4 marks – June 2007) 4 (c) Earthquakes are another example of tectonic activity. Describe the primary and secondary effects of an earthquake. (4 marks – June 2008) 1 (d) Describe how the effects of an earthquake in a richer area of the world are different from the effects of an earthquake in a poor ...
Non-chondritic sulphur isotope composition of the terrestrial mantle
... Sr 5 327 p.p.m., Nd 5 27 p.p.m. and S 5 5,700 p.p.m. Markers on the fits are separated by 0.1%, 1.0% and 4.0% for sediment, LCC and SCLM, respectively. ...
... Sr 5 327 p.p.m., Nd 5 27 p.p.m. and S 5 5,700 p.p.m. Markers on the fits are separated by 0.1%, 1.0% and 4.0% for sediment, LCC and SCLM, respectively. ...
Plate motions, slab dynamics and back
... 1978; Dewey, 1980; Garfunkel et al., 1986), and thus an extensional back-arc deformation (Fig. 4). According to this “slab rollback model” (1) seaward trench motion should be an ubiquitous feature of oceanic subduction zones; (2) the older and colder a slab is, the harder it should pull down on the ...
... 1978; Dewey, 1980; Garfunkel et al., 1986), and thus an extensional back-arc deformation (Fig. 4). According to this “slab rollback model” (1) seaward trench motion should be an ubiquitous feature of oceanic subduction zones; (2) the older and colder a slab is, the harder it should pull down on the ...
Plate motions, slab dynamics and back
... 1978; Dewey, 1980; Garfunkel et al., 1986), and thus an extensional back-arc deformation (Fig. 4). According to this “slab rollback model” (1) seaward trench motion should be an ubiquitous feature of oceanic subduction zones; (2) the older and colder a slab is, the harder it should pull down on the ...
... 1978; Dewey, 1980; Garfunkel et al., 1986), and thus an extensional back-arc deformation (Fig. 4). According to this “slab rollback model” (1) seaward trench motion should be an ubiquitous feature of oceanic subduction zones; (2) the older and colder a slab is, the harder it should pull down on the ...
A reassessment of the timing of early Archaean crustal
... believed to be as old as 3.87 Ga (Nutman et al. 1997a). However, a closer inspection of the age spectra, in other words the data themselves, reveals that an alternative interpretation is equally plausible. The ion-probe U-Pb zircon age spectra of all three analysed discordant gneiss sheets can be st ...
... believed to be as old as 3.87 Ga (Nutman et al. 1997a). However, a closer inspection of the age spectra, in other words the data themselves, reveals that an alternative interpretation is equally plausible. The ion-probe U-Pb zircon age spectra of all three analysed discordant gneiss sheets can be st ...
Earth SC-1002 Geological Wonder of Oman
... (iv) Crust: 6 to 60 km in thickness, made of silicates that are less dense then those in the mantle. The crust is of two kinds: (Table 2) (a) Continental crust made mostly of sedimentary and acidic or felsic igneous rocks, with an average thickness of 35 km but reaching 60 km in high mountain ranges ...
... (iv) Crust: 6 to 60 km in thickness, made of silicates that are less dense then those in the mantle. The crust is of two kinds: (Table 2) (a) Continental crust made mostly of sedimentary and acidic or felsic igneous rocks, with an average thickness of 35 km but reaching 60 km in high mountain ranges ...
The Makran, Southeastern Iran: the anatomy of a convergent plate
... a whole--following the curvature of this Inner Makran spreading zone round from a northsouth trend in the NW of the area to east-west near Fannuj. This suggests that these ophiolites were formed in approximately their present positions and have not been tectonically emplaced from elsewhere. Indeed t ...
... a whole--following the curvature of this Inner Makran spreading zone round from a northsouth trend in the NW of the area to east-west near Fannuj. This suggests that these ophiolites were formed in approximately their present positions and have not been tectonically emplaced from elsewhere. Indeed t ...
Are `hot spots` - Durham University Community
... the predictions of the plate hypothesis contrast with those of the plume hypothesis in that the mantle is not considered to be essentially isothermal everywhere except for discrete, isolated, spot-like high-TP anomalies of several hundred degrees Celsius. Unusually productive parts of the mid-ocean ...
... the predictions of the plate hypothesis contrast with those of the plume hypothesis in that the mantle is not considered to be essentially isothermal everywhere except for discrete, isolated, spot-like high-TP anomalies of several hundred degrees Celsius. Unusually productive parts of the mid-ocean ...
Exhuming Norwegian ultrahigh-pressure rocks
... 1. Introduction [2] The discovery over the past two decades that ultrahigh-pressure (UHP) rocks are distributed around the globe is changing fundamental concepts behind our understanding of the interaction between the crust and the mantle, and of the kinematics of continental collisions. In particul ...
... 1. Introduction [2] The discovery over the past two decades that ultrahigh-pressure (UHP) rocks are distributed around the globe is changing fundamental concepts behind our understanding of the interaction between the crust and the mantle, and of the kinematics of continental collisions. In particul ...
Geosphere - Squarespace
... concentrations of atmospheric CO2 . Hypotheses for the elevated CO2 concentrations invoke an increase in volcanic CO2 production due to higher oceanic crust production rates, higher frequency of large igneous provinces, or increases in pelagic carbonate deposition, the last leading to enhanced carbo ...
... concentrations of atmospheric CO2 . Hypotheses for the elevated CO2 concentrations invoke an increase in volcanic CO2 production due to higher oceanic crust production rates, higher frequency of large igneous provinces, or increases in pelagic carbonate deposition, the last leading to enhanced carbo ...
Receiver function images of the Hellenic subduction zone and
... vertical margins of forearc slivers the seismicity extends down to the subduction interface (Meier et al., 2007; Becker et al., 2009; Brüstle et al., 2014). The seismicity of the plate contact is only incompletely recorded due to the limited station coverage by permanent and temporary networks. In t ...
... vertical margins of forearc slivers the seismicity extends down to the subduction interface (Meier et al., 2007; Becker et al., 2009; Brüstle et al., 2014). The seismicity of the plate contact is only incompletely recorded due to the limited station coverage by permanent and temporary networks. In t ...
Niches of the pre-photosynthetic biosphere and geologic
... temperature, as illustrated by the solid curves in Fig. 1, denoting the two alternate standard states adopted above. The solid curves are isopleths for ∆G1 = 0, that is, equilibrium for reaction 1 numerically represented by values for the standard Gibbs energy of reaction ( ∆G°1) divided by 2.3 RT, ...
... temperature, as illustrated by the solid curves in Fig. 1, denoting the two alternate standard states adopted above. The solid curves are isopleths for ∆G1 = 0, that is, equilibrium for reaction 1 numerically represented by values for the standard Gibbs energy of reaction ( ∆G°1) divided by 2.3 RT, ...
Plate tectonics
Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός ""pertaining to building"") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s.The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.