OBSERVATIONAL AND THEORETICAL STUDIES OF THE DYNAMICS OF MANTLE PLUME–MID-OCEAN RIDGE INTERACTION
... [4] Basalts associated with hot spot volcanism generally display elevated concentrations of incompatible elements and radiogenic isotope concentrations that indicate these enrichments are long-lived (⬎108 years). In contrast, mid-ocean ridge basalts (MORBs) display low concentrations of many of thes ...
... [4] Basalts associated with hot spot volcanism generally display elevated concentrations of incompatible elements and radiogenic isotope concentrations that indicate these enrichments are long-lived (⬎108 years). In contrast, mid-ocean ridge basalts (MORBs) display low concentrations of many of thes ...
Ridge push, mantle plumes and the speed of the Indian plate
... 28, which was probably preceded by extension of transitional crust during chron 30. I N D I A N P L AT E M O T I O N A N D D R I V I N G T O RQ U E S van Hinsbergen et al. (2011) used two geodynamic models to examine the tilting and dragging effects of the arrival and expansion of the mantle plume h ...
... 28, which was probably preceded by extension of transitional crust during chron 30. I N D I A N P L AT E M O T I O N A N D D R I V I N G T O RQ U E S van Hinsbergen et al. (2011) used two geodynamic models to examine the tilting and dragging effects of the arrival and expansion of the mantle plume h ...
Why the Philippine Sea Plate Moves as It Does
... Seismic images (ie catscan-like images of the distribution of seismic velocities) of the mantle show that subducting plates reach at least as deep as 670 km and in places perhaps deeper. Some plates seem to bottom out at this level,which implies that convection is limited to the upper mantle. There ...
... Seismic images (ie catscan-like images of the distribution of seismic velocities) of the mantle show that subducting plates reach at least as deep as 670 km and in places perhaps deeper. Some plates seem to bottom out at this level,which implies that convection is limited to the upper mantle. There ...
Speculations on the Consequences and Causes of Plate Motions*
... had maintained that trenches were the site of such destruction for many years, but until recently there was rather little evidence in favour of this belief. In particular the negative gravity anomalies in trenches were used by Vening Meinesz to support the theory of crustal contraction, and by Worze ...
... had maintained that trenches were the site of such destruction for many years, but until recently there was rather little evidence in favour of this belief. In particular the negative gravity anomalies in trenches were used by Vening Meinesz to support the theory of crustal contraction, and by Worze ...
Geology: Fluids in the lower crust following Mendocino triple
... layer which has velocities typical of mafic lithologies, while the deeper reflections are at the level of Moho formation. This is similar to the midocean ridges where melt due to upwelling asthenosphere is found in discrete bodies, both shallow and near the oceanic Moho (Kent et al., 1993; Garmany, ...
... layer which has velocities typical of mafic lithologies, while the deeper reflections are at the level of Moho formation. This is similar to the midocean ridges where melt due to upwelling asthenosphere is found in discrete bodies, both shallow and near the oceanic Moho (Kent et al., 1993; Garmany, ...
Metadolerites of the Vrbno Group and their origin, the
... In the deformed and retrogressively metamorphosed parts and/or on margins of thicker bodies, the metadolerites pass to greenschists of grey-green to green colour, locally sericitechlorite schists. Metadolerite bodies in borehole JR-10 are massive in the centre and intensively cleaved on the margins. ...
... In the deformed and retrogressively metamorphosed parts and/or on margins of thicker bodies, the metadolerites pass to greenschists of grey-green to green colour, locally sericitechlorite schists. Metadolerite bodies in borehole JR-10 are massive in the centre and intensively cleaved on the margins. ...
Are `hot spots` - Durham University Community
... inspired by Hawaii – a unique phenomenon, given its intraplate setting, huge present-day volcanic production rate, and exceptionally long, narrow, time-progressive volcanic chain. The term ‘hot spot’ subsequently became inexorably linked with the plume hypothesis, which was developed to explain how ...
... inspired by Hawaii – a unique phenomenon, given its intraplate setting, huge present-day volcanic production rate, and exceptionally long, narrow, time-progressive volcanic chain. The term ‘hot spot’ subsequently became inexorably linked with the plume hypothesis, which was developed to explain how ...
Chapter 17: Plate Tectonics
... maps of the seafloor. You’ll learn more about magnetism and how it supports the hypothesis of continental drift later in this section. ...
... maps of the seafloor. You’ll learn more about magnetism and how it supports the hypothesis of continental drift later in this section. ...
Melt Band Formation in a Mid
... It has been well established through a variety of experimental and numerical studies that imposing an external shear on a system of partial melt will result in the compaction of the solid matrix and expulsion of the interstitial liquid melt; this leads to the formation of regions of contrasting high ...
... It has been well established through a variety of experimental and numerical studies that imposing an external shear on a system of partial melt will result in the compaction of the solid matrix and expulsion of the interstitial liquid melt; this leads to the formation of regions of contrasting high ...
Nevado de Longaví Volcano (Chilean Andes, 36.2 ˚S): adakitic
... unusually high B (19-55 ppm), are consistent with important slab-derived fluid contributions. The NLV adakitic dacites have high Sr (∼590 ppm) and Sr/Y (∼70), indicative of suppression of plagioclase crystallization combined with the fractionation of phases for which Y and HREE are compatible. This ...
... unusually high B (19-55 ppm), are consistent with important slab-derived fluid contributions. The NLV adakitic dacites have high Sr (∼590 ppm) and Sr/Y (∼70), indicative of suppression of plagioclase crystallization combined with the fractionation of phases for which Y and HREE are compatible. This ...
Seismic constraints on Ear th`s small-sc
... techniques. Seismology is one of the best remote sensing tools used to study the Earth’s interior, and many major discoveries of structures in the deep Earth (such as the existence of the inner and outer core and the crust–mantle boundary) have been made using seismological techniques. Despite consi ...
... techniques. Seismology is one of the best remote sensing tools used to study the Earth’s interior, and many major discoveries of structures in the deep Earth (such as the existence of the inner and outer core and the crust–mantle boundary) have been made using seismological techniques. Despite consi ...
3 The backdrop – a 70 million year old Plain
... The Monaro Volcanic Province is marked in blue on the map above. It is clear from the distribution of outliers of basalt, indicated by the scattered, patchy margin, that the province once covered a much larger area. The geological cause of these eruptions has yet to be clearly established, but their ...
... The Monaro Volcanic Province is marked in blue on the map above. It is clear from the distribution of outliers of basalt, indicated by the scattered, patchy margin, that the province once covered a much larger area. The geological cause of these eruptions has yet to be clearly established, but their ...
101 - Durham University Community
... Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with “hotspots” or “mantle plumes”. While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, ...
... Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with “hotspots” or “mantle plumes”. While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, ...
The Origin of the Land Under the Sea
... transported deep melts up through the shallow mantle beneath a mid-ocean ridge. We were seeing dissolution channels frozen in time. As exciting as these discoveries were, they did not fully explain a second mystery that long perplexed geophysicists. The massive lava flows at mid-ocean ridges emerge ...
... transported deep melts up through the shallow mantle beneath a mid-ocean ridge. We were seeing dissolution channels frozen in time. As exciting as these discoveries were, they did not fully explain a second mystery that long perplexed geophysicists. The massive lava flows at mid-ocean ridges emerge ...
Earth Structure - Processes in Structural Geology and Tectonics
... Oceanic crust can all be subdivided into the same distinct layers, worldwide. Continental crust is very heterogeneous, reflecting its complex history and the fact that different regions of continental crust formed in different ways. ...
... Oceanic crust can all be subdivided into the same distinct layers, worldwide. Continental crust is very heterogeneous, reflecting its complex history and the fact that different regions of continental crust formed in different ways. ...
1 The tectonic agenda
... materials, including peridotite, is a function of temperature; at asthenospheric temperatures (approximately 1300o C) peridotite ( for peridotite α is about 10−5 o K−1 ) is sufficiently weak that it will convect in response to stresses resulting from the density variations associated with small late ...
... materials, including peridotite, is a function of temperature; at asthenospheric temperatures (approximately 1300o C) peridotite ( for peridotite α is about 10−5 o K−1 ) is sufficiently weak that it will convect in response to stresses resulting from the density variations associated with small late ...
Chapter 17: Plate Tectonics
... maps of the seafloor. You’ll learn more about magnetism and how it supports the hypothesis of continental drift later in this section. ...
... maps of the seafloor. You’ll learn more about magnetism and how it supports the hypothesis of continental drift later in this section. ...
Deep structure and mechanical behavior of the lithosphere in the
... Karner and Watts [37], Burov et al. [35] or Caporali [38], that the Moho is maintained at depths di¡erent than predicted by the Airy model across these faults by vertical forces acting on rigid lithospheric plates. These forces are linked to complex tectonic interactions between far-¢eld horizontal ...
... Karner and Watts [37], Burov et al. [35] or Caporali [38], that the Moho is maintained at depths di¡erent than predicted by the Airy model across these faults by vertical forces acting on rigid lithospheric plates. These forces are linked to complex tectonic interactions between far-¢eld horizontal ...
Plate Tectonics - El Camino College
... from mid-ocean ridges and towards trenches. However, the plates run into one another, so they resist being moved. Instead of moving, the plates are “squeezed” and “twisted” where they collide. Eventually, they cannot deform any more, and the pressure to move builds up until it overcomes the resistan ...
... from mid-ocean ridges and towards trenches. However, the plates run into one another, so they resist being moved. Instead of moving, the plates are “squeezed” and “twisted” where they collide. Eventually, they cannot deform any more, and the pressure to move builds up until it overcomes the resistan ...
The thermal structure of subduction zones constrained by seismic
... It is more realistic to model the mantle of the wedge as a medium with strongly temperature- and stress-dependent rheology, which is characteristic of the deformation of the dominant minerals under mantle conditions. In Figure 5b we show the temperature field obtained with rheology based on disloca ...
... It is more realistic to model the mantle of the wedge as a medium with strongly temperature- and stress-dependent rheology, which is characteristic of the deformation of the dominant minerals under mantle conditions. In Figure 5b we show the temperature field obtained with rheology based on disloca ...
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.