2. Geophysics and the Structure of the Lesser Antilles Forearc
... The subduction zone of the Lesser Antilles forms the eastern boundary of the Caribbean Plate, where Atlantic oceanic lithosphere of the North and South American plates passes beneath it. The predominantly easterly direction of plate convergence at the boundary has been inferred primarily from the no ...
... The subduction zone of the Lesser Antilles forms the eastern boundary of the Caribbean Plate, where Atlantic oceanic lithosphere of the North and South American plates passes beneath it. The predominantly easterly direction of plate convergence at the boundary has been inferred primarily from the no ...
The lithosphere and asthenosphere of the Iceland hotspot from
... second the layer of the lower crust. The half of Iceland surveyed had a weighted average crustal thickness of 25–26 km, less than previously estimated. It is under East and East Central Iceland that the crust is thickest, averaging 29–32 ± 3 km, and under the western margin of the West Fjords, 29 ± ...
... second the layer of the lower crust. The half of Iceland surveyed had a weighted average crustal thickness of 25–26 km, less than previously estimated. It is under East and East Central Iceland that the crust is thickest, averaging 29–32 ± 3 km, and under the western margin of the West Fjords, 29 ± ...
The lithosphere and asthenosphere of the
... second the layer of the lower crust. The half of Iceland surveyed had a weighted average crustal thickness of 25–26 km, less than previously estimated. It is under East and East Central Iceland that the crust is thickest, averaging 29–32 ± 3 km, and under the western margin of the West Fjords, 29 ± ...
... second the layer of the lower crust. The half of Iceland surveyed had a weighted average crustal thickness of 25–26 km, less than previously estimated. It is under East and East Central Iceland that the crust is thickest, averaging 29–32 ± 3 km, and under the western margin of the West Fjords, 29 ± ...
Origin and consequences of western Mediterranean subduction
... Rosenbaum et al., 2002a] associated with slab rupture along and removal of slab under the North African margin [Gutscher et al., 2002; Mauffret et al., 2004; Spakman and Wortel, 2004; Duggen et al., 2003, 2004, 2005] (Figure 2). In the first case, a wide slab from Gibraltar to Corsica started to roll ...
... Rosenbaum et al., 2002a] associated with slab rupture along and removal of slab under the North African margin [Gutscher et al., 2002; Mauffret et al., 2004; Spakman and Wortel, 2004; Duggen et al., 2003, 2004, 2005] (Figure 2). In the first case, a wide slab from Gibraltar to Corsica started to roll ...
Available - UNLV Geoscience - University of Nevada, Las Vegas
... The discovery of synconvergent extension within the interiors of modern convergent orogens (e.g., Dalmayrac and Molnar, 1981; Molnar and Chen, 1983) has provided insights into the processes that control crustal thickness and topography during orogenesis. Topography and crustal thickness are governed ...
... The discovery of synconvergent extension within the interiors of modern convergent orogens (e.g., Dalmayrac and Molnar, 1981; Molnar and Chen, 1983) has provided insights into the processes that control crustal thickness and topography during orogenesis. Topography and crustal thickness are governed ...
STUDyIng EArTh`S LAyErS
... may not come in the form of little green alien visitors but instead be found in the rocks known as meteorites that fall to the planet’s surface. Meteorites are evidence of other rocky planets that may not have survived as the Earth did. Most meteorites come in three forms: stony, iron-based, and sto ...
... may not come in the form of little green alien visitors but instead be found in the rocks known as meteorites that fall to the planet’s surface. Meteorites are evidence of other rocky planets that may not have survived as the Earth did. Most meteorites come in three forms: stony, iron-based, and sto ...
The Cordilleran Ribbon Continent of North America
... If the Cordillera is, therefore, strictly attributable to accretionary processes, the bulk of the orogen may consist of little-disturbed North American crust underpinned by North American mantle (Cook et al. 2004, Snyder et al. 2002). I start by reviewing the basic character of the Canadian portion ...
... If the Cordillera is, therefore, strictly attributable to accretionary processes, the bulk of the orogen may consist of little-disturbed North American crust underpinned by North American mantle (Cook et al. 2004, Snyder et al. 2002). I start by reviewing the basic character of the Canadian portion ...
Geodynamic models of Cordilleran orogens
... Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA, and ...
... Department of Geosciences, University of Arizona, Tucson, Arizona 85721, USA, and ...
Cenozoic magmatism in the western Ross Embayment:
... Wilson [1963] and Morgan [1971], plume occurrence has been frequently postulated just on the basis of magma chemistry, and plume theory has been stretched to the point that at least in some instances simpler explanations can be found. This controversy should be addressed in an integrated geological ...
... Wilson [1963] and Morgan [1971], plume occurrence has been frequently postulated just on the basis of magma chemistry, and plume theory has been stretched to the point that at least in some instances simpler explanations can be found. This controversy should be addressed in an integrated geological ...
Igneous Rock Associations 8. Arc Magmatism II: Geo
... settings, and are known as high-alumina basalt. Although their origin is unclear, their low MgO content suggests that they are fractionated (by removal of olivine and augite) from a more mafic parent. The high Al2O3 implies that plagioclase was not a liquidus phase. Two suites, or collections of mag ...
... settings, and are known as high-alumina basalt. Although their origin is unclear, their low MgO content suggests that they are fractionated (by removal of olivine and augite) from a more mafic parent. The high Al2O3 implies that plagioclase was not a liquidus phase. Two suites, or collections of mag ...
93. Lee, C. - Squarespace
... Data were filtered to exclude rocks that were obviously cumulates (e.g., olivine gabbros), but not all cumulates, especially those with intermediate compositions, could be excluded due to the difficulty in distinguishing cumulates from magmas based on major ...
... Data were filtered to exclude rocks that were obviously cumulates (e.g., olivine gabbros), but not all cumulates, especially those with intermediate compositions, could be excluded due to the difficulty in distinguishing cumulates from magmas based on major ...
Local modification of the lithosphere beneath the central and
... al., 2011). However, most of these existing studies are confined to sparse spots, discrete areas or linear profiles, and hence are difficult to yield integrated lithospheric images for the entire central and western NCC. A detailed 3-D structural model is needed for delineating the spatial extent of th ...
... al., 2011). However, most of these existing studies are confined to sparse spots, discrete areas or linear profiles, and hence are difficult to yield integrated lithospheric images for the entire central and western NCC. A detailed 3-D structural model is needed for delineating the spatial extent of th ...
Curriculum - lsdsecondarysciencesteeringcommittee
... Motion histories are determined with calculations that relate rate, time, and distance of offset geologic features. Oceanic plates are created at mid-ocean ridges by magmatic activity and cooled until they sink back into the Earth at subduction zones. At some localities, plates slide by each other. ...
... Motion histories are determined with calculations that relate rate, time, and distance of offset geologic features. Oceanic plates are created at mid-ocean ridges by magmatic activity and cooled until they sink back into the Earth at subduction zones. At some localities, plates slide by each other. ...
PDF Version - Bullard Laboratories
... influenced by the behaviour of the Iceland Plume, whose striking dominance is manifest by long-wavelength free-air gravity anomalies and by oceanic bathymetric anomalies. Here, we use these anomalies to estimate the amplitude and wavelength of present-day dynamic uplift associated with this plume. M ...
... influenced by the behaviour of the Iceland Plume, whose striking dominance is manifest by long-wavelength free-air gravity anomalies and by oceanic bathymetric anomalies. Here, we use these anomalies to estimate the amplitude and wavelength of present-day dynamic uplift associated with this plume. M ...
Crustal thickness anomalies in the North Atlantic Ocean Tingting Wang
... remaining 35% is >7 km thick and is interpreted to have been affected by excess magmatism. Thin crust probably reflects reduced melt production from relatively cold or refractory mantle at scales of up to hundreds of kilometers along the spreading axis. By far the most prominent thick crust anomaly ...
... remaining 35% is >7 km thick and is interpreted to have been affected by excess magmatism. Thin crust probably reflects reduced melt production from relatively cold or refractory mantle at scales of up to hundreds of kilometers along the spreading axis. By far the most prominent thick crust anomaly ...
Nature template
... timing and amplitude of these phases may be slightly altered by possible interference with smaller reverberations from discontinuities internal to the crust. However, although the possibility of such interference leads to uncertainties in the depth and gradient associated with a discontinuity at the ...
... timing and amplitude of these phases may be slightly altered by possible interference with smaller reverberations from discontinuities internal to the crust. However, although the possibility of such interference leads to uncertainties in the depth and gradient associated with a discontinuity at the ...
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 ...
The Dynamic Earth - Betavak-NLT
... has very few visible crystals. Basalt often forms at the bottom of the ocean, where the heat dissipates quickly in the cold seawater. When molten material cools slowly there is time for a greater number of crystals to form. If there is enough space, these crystals will be larger too. An example of a ...
... has very few visible crystals. Basalt often forms at the bottom of the ocean, where the heat dissipates quickly in the cold seawater. When molten material cools slowly there is time for a greater number of crystals to form. If there is enough space, these crystals will be larger too. An example of a ...
Where and why do large shallow intraslab earthquakes occur?
... was felt in a wide area, which is a characteristic feature of intraslab events in this area. The 1905 Geiyo earthquake (Event 4) occurred northwest of Shikoku. Close to the epicenter of this earthquake, a large earthquake (the 2001 Geiyo earthquake, Event 3, Mw 6.8) occurred on 24 March 2001 at a de ...
... was felt in a wide area, which is a characteristic feature of intraslab events in this area. The 1905 Geiyo earthquake (Event 4) occurred northwest of Shikoku. Close to the epicenter of this earthquake, a large earthquake (the 2001 Geiyo earthquake, Event 3, Mw 6.8) occurred on 24 March 2001 at a de ...
Subduction zone evolution and deep slab structure
... The evolution of the Mediterranean subduction zones and their deep slab structure started during the Late Cretaceous and is a result of the relative movement of the African and European plate including the independent motion of five microplates (Adria, Iberia, Alcapia, and Tiszia), which caused subd ...
... The evolution of the Mediterranean subduction zones and their deep slab structure started during the Late Cretaceous and is a result of the relative movement of the African and European plate including the independent motion of five microplates (Adria, Iberia, Alcapia, and Tiszia), which caused subd ...
- Wiley Online Library
... Tibetan crust south of the Kunlun Fault have been observed; the geometries and boundaries of some of these are associated with major tectonic sutures. The conductive zones are explained by various temperature-driven mechanisms, including aqueous (hydrothermal) fluids, partial melting, or a combinatio ...
... Tibetan crust south of the Kunlun Fault have been observed; the geometries and boundaries of some of these are associated with major tectonic sutures. The conductive zones are explained by various temperature-driven mechanisms, including aqueous (hydrothermal) fluids, partial melting, or a combinatio ...
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.