Density modeling of the Escollos Alijos Seamount
... The Escollos Alijos seamount is located at 24º 50’N latitude and 115º 34’W longitude, about 300 km off the western continental margin of the Baja California peninsula (Figure 1). The bathymetry shows that the seamount is a compound of two flat-topped edifices, about 60 km by 40 km long at its base, ...
... The Escollos Alijos seamount is located at 24º 50’N latitude and 115º 34’W longitude, about 300 km off the western continental margin of the Baja California peninsula (Figure 1). The bathymetry shows that the seamount is a compound of two flat-topped edifices, about 60 km by 40 km long at its base, ...
Subduction factory 2. Are intermediate
... resistance from the lower mantle; they also noted that some slabs (e.g., those now known to have double seismic zones) have stress states not readily explained by this simple model. Intermediate-depth seismicity has also been explained as the result of unbending of the slab following bending at the ...
... resistance from the lower mantle; they also noted that some slabs (e.g., those now known to have double seismic zones) have stress states not readily explained by this simple model. Intermediate-depth seismicity has also been explained as the result of unbending of the slab following bending at the ...
Continental Margin Deformation along the Andean Subduction zone
... deformation, as we restrict our modelling approach to 2D, as well as to the upper 300 km shell of the Earth. On the other hand, these latter studies do not focus on the detailed elastoplastic rheology of the overriding lithosphere, which however will be investigated here. Bonnardot et al. (2008) ...
... deformation, as we restrict our modelling approach to 2D, as well as to the upper 300 km shell of the Earth. On the other hand, these latter studies do not focus on the detailed elastoplastic rheology of the overriding lithosphere, which however will be investigated here. Bonnardot et al. (2008) ...
Rifting, Seafloor Spreading, and Extensional Tectonics
... Earth’s gravity, rock isn’t strong enough for such gaps to remain open, so either the hanging wall breaks up into fault slices (Figure 16.6b), or it sinks downward and curves to form a rollover anticline (Figure 16.7b). Though slip on planar normal faults can occur without rotation (i.e., making the ...
... Earth’s gravity, rock isn’t strong enough for such gaps to remain open, so either the hanging wall breaks up into fault slices (Figure 16.6b), or it sinks downward and curves to form a rollover anticline (Figure 16.7b). Though slip on planar normal faults can occur without rotation (i.e., making the ...
mid-ocean ridges: mantle convection
... ‘active’ or ‘buoyant’ mantle upwelling and further contribute to decompression melting, as we discuss below. Several lines of evidence indicate that the upwelling is restricted to the upper mantle. The pressures at which key mineralogical transitions occur in the deep upper mantle (i.e., at depths 4 ...
... ‘active’ or ‘buoyant’ mantle upwelling and further contribute to decompression melting, as we discuss below. Several lines of evidence indicate that the upwelling is restricted to the upper mantle. The pressures at which key mineralogical transitions occur in the deep upper mantle (i.e., at depths 4 ...
A source for Icelandic magmas in remelted Iapetus crust
... supercontinent broke up again at ~54 Ma when the North Atlantic began to form. At this time, continental lithosphere fertilised by crust trapped during the earlier continental suturing may have delaminated and been recycled into the asthenosphere that now underlies the North Atlantic. In the future ...
... supercontinent broke up again at ~54 Ma when the North Atlantic began to form. At this time, continental lithosphere fertilised by crust trapped during the earlier continental suturing may have delaminated and been recycled into the asthenosphere that now underlies the North Atlantic. In the future ...
Late Variscan (Carboniferous to Permian) environments in the
... quartzites and porphyroids. Based on the lithological correlations, the whole sequence is generally divided into: i) the lower, coarse-grained Guadalupian?-Lopingian “Alpine Verrucano” (including rhyolitic volcanic materials) and ii) the upper, finergrained Scythian quarzites (“Skythquarzite”)*. *No ...
... quartzites and porphyroids. Based on the lithological correlations, the whole sequence is generally divided into: i) the lower, coarse-grained Guadalupian?-Lopingian “Alpine Verrucano” (including rhyolitic volcanic materials) and ii) the upper, finergrained Scythian quarzites (“Skythquarzite”)*. *No ...
Durham Research Online
... Handy and Brun, 2004; Burov, 2011]. Our elusive knowledge of those parameters complicates modelling the continental subduction dynamics. Moreover, continents differ from each other because of their diverse formation, composition, age and thermal history, all features that affect the rheological prop ...
... Handy and Brun, 2004; Burov, 2011]. Our elusive knowledge of those parameters complicates modelling the continental subduction dynamics. Moreover, continents differ from each other because of their diverse formation, composition, age and thermal history, all features that affect the rheological prop ...
A new model of lunar crust: asymmetry in crustal composition... Tomoko Arai , Hiroshi Takeda , Akira Yamaguchi
... The recent remote-sensing data, such as those from Clementine and Lunar Prospector, have revealed that the globe-wide surface composition is extremely heterogeneous and the internal structure is not uniform. These findings indicate that the Apollo-era models of the lunar crustal evolution are too si ...
... The recent remote-sensing data, such as those from Clementine and Lunar Prospector, have revealed that the globe-wide surface composition is extremely heterogeneous and the internal structure is not uniform. These findings indicate that the Apollo-era models of the lunar crustal evolution are too si ...
visualization 3: earthquakes at divergent plate
... of spreading. These earthquakes are also very shallow (earthquakes at spreading ridges range from 0 to 33 km below the surface) because the crust is very thin. • These earthquakes tend to be small because the crust is thin and there is high heat flow. Therefore, the lithosphere is weak at these boun ...
... of spreading. These earthquakes are also very shallow (earthquakes at spreading ridges range from 0 to 33 km below the surface) because the crust is very thin. • These earthquakes tend to be small because the crust is thin and there is high heat flow. Therefore, the lithosphere is weak at these boun ...
︎PDF - Fabio Crameri
... emerging mobile surface plates in mantle convection simulations, is a long-standing challenge. The majority of mantle convection models featuring a mobile lid thus impose some aspect such as plate velocity, trench velocity, or weak zones [see Bercovici et al., 2000; Lowman, 2011, and references ther ...
... emerging mobile surface plates in mantle convection simulations, is a long-standing challenge. The majority of mantle convection models featuring a mobile lid thus impose some aspect such as plate velocity, trench velocity, or weak zones [see Bercovici et al., 2000; Lowman, 2011, and references ther ...
Subduction of oceanic lithosphere
... This model accounts for the entrainment of the asthenosphere by the downgoing slab (which makes it colder at given depth. There is a narrow window where the geotherm intersects the solidus for wet mantle. (a) Material movement (arrows) and temperature structure (dashed lines) of a simplified converg ...
... This model accounts for the entrainment of the asthenosphere by the downgoing slab (which makes it colder at given depth. There is a narrow window where the geotherm intersects the solidus for wet mantle. (a) Material movement (arrows) and temperature structure (dashed lines) of a simplified converg ...
Mission Moho Workshop: Drilling Through the Oceanic Crust to the
... The direct route to the Moho: There was a clear workshop consensus that the first priority for a Mission Moho should be a deep, full crustal penetration hole through the Moho and into the uppermost mantle at a single site and that the first full-penetration hole should be in fast-spread ocean crust. ...
... The direct route to the Moho: There was a clear workshop consensus that the first priority for a Mission Moho should be a deep, full crustal penetration hole through the Moho and into the uppermost mantle at a single site and that the first full-penetration hole should be in fast-spread ocean crust. ...
IgPetMORB13
... crust averages about 6 km in thickness, but ranges from 0 km at mid-ocean ridges to 10 km near the continents. Ophiolites are thought to be sections of oceanic crust “obducted” onto land. These sequences suggest that the oceanic crust consists of a thin layer of sediments (layer 1) over basaltic pil ...
... crust averages about 6 km in thickness, but ranges from 0 km at mid-ocean ridges to 10 km near the continents. Ophiolites are thought to be sections of oceanic crust “obducted” onto land. These sequences suggest that the oceanic crust consists of a thin layer of sediments (layer 1) over basaltic pil ...
MORB13
... crust averages about 6 km in thickness, but ranges from 0 km at mid-ocean ridges to 10 km near the continents. Ophiolites are thought to be sections of oceanic crust “obducted” onto land. These sequences suggest that the oceanic crust consists of a thin layer of sediments (layer 1) over basaltic pil ...
... crust averages about 6 km in thickness, but ranges from 0 km at mid-ocean ridges to 10 km near the continents. Ophiolites are thought to be sections of oceanic crust “obducted” onto land. These sequences suggest that the oceanic crust consists of a thin layer of sediments (layer 1) over basaltic pil ...
Small-scale upper mantle convection and crustal dynamics in
... interaction stresses; we show that much of the deformation that cannot be explained by plate interaction derives from small-scale convection of the underlying upper mantle. [3] Approximately 50 mm/yr of relative motion between the Pacific and North American plates [DeMets and Dixon, 1999] is accommo ...
... interaction stresses; we show that much of the deformation that cannot be explained by plate interaction derives from small-scale convection of the underlying upper mantle. [3] Approximately 50 mm/yr of relative motion between the Pacific and North American plates [DeMets and Dixon, 1999] is accommo ...
Anderson and Natland, 2005
... shallow return flow, and passive convection, with cooling plates and slabs the active elements. In this contribution we summarize the early history and the development of key ideas for features that have been called melting anomalies, midplate volcanism, hotspots, and linear volcanic chains or hotsp ...
... shallow return flow, and passive convection, with cooling plates and slabs the active elements. In this contribution we summarize the early history and the development of key ideas for features that have been called melting anomalies, midplate volcanism, hotspots, and linear volcanic chains or hotsp ...
as a PDF
... most suitable for analysis of a specific geological setting. Here, we wish to provide an overview of what has been learned about subduction dynamics from both approaches. We start with a review of observations of surface velocities and the implications of their vectorial character and spatial gradie ...
... most suitable for analysis of a specific geological setting. Here, we wish to provide an overview of what has been learned about subduction dynamics from both approaches. We start with a review of observations of surface velocities and the implications of their vectorial character and spatial gradie ...
World Heritage Volcanoes
... in the geological past the pattern of plates and therefore the distribution of volcanoes changed constantly throughout time. This means that in addition to present day volcanoes, we also find evidence of ancient volcanism in the historical, or stratigraphical, record, at locations typically remote f ...
... in the geological past the pattern of plates and therefore the distribution of volcanoes changed constantly throughout time. This means that in addition to present day volcanoes, we also find evidence of ancient volcanism in the historical, or stratigraphical, record, at locations typically remote f ...
Mantle convection in the Middle East: Reconciling Afar - HAL-Insu
... regions are found behind the Aegean trench and in the Makran–Persian Gulf (Barrier and Vrielynck, 2010). The vertical motion of these areas is Neogene to Recent and its origins are still poorly understood (Şengör et al., 2003 and Göğüş and Pysklywec, 2008). Residual topography, computed by removing ...
... regions are found behind the Aegean trench and in the Makran–Persian Gulf (Barrier and Vrielynck, 2010). The vertical motion of these areas is Neogene to Recent and its origins are still poorly understood (Şengör et al., 2003 and Göğüş and Pysklywec, 2008). Residual topography, computed by removing ...
Mantle Melting Beneath Mid-Ocean Ridges The Harvard community
... and 60–100 km of mantle that is depleted in these elements. When this plate is recycled into the mantle at convergent margins, these heterogeneities gradually become mixed, but differences in density and stiffness will preserve variations on ...
... and 60–100 km of mantle that is depleted in these elements. When this plate is recycled into the mantle at convergent margins, these heterogeneities gradually become mixed, but differences in density and stiffness will preserve variations on ...
A crustal model of the ultrahigh-pressure Dabie Shan orogenic belt
... 270 km following Pn. This phase (P x ) cannot simply be the asympotic wide-angle PmP reflection because, in this case, the apparent velocity would be equal to the velocity of the lower crust (6.6 – 6.9 km/s in this region). The travel time and amplitude of this phase are similar to a prominent phase ...
... 270 km following Pn. This phase (P x ) cannot simply be the asympotic wide-angle PmP reflection because, in this case, the apparent velocity would be equal to the velocity of the lower crust (6.6 – 6.9 km/s in this region). The travel time and amplitude of this phase are similar to a prominent phase ...
How Mantle Slabs Drive Plate Tectonics
... the subject of debate for some time (2–7). Mantle convection may be driven primarily by the descent of dense slabs of subducted oceanic lithosphere (8 –10), which are the most prominent density heterogeneities in the mantle (11, 12). The motions of the surface plates have also been attributed to the ...
... the subject of debate for some time (2–7). Mantle convection may be driven primarily by the descent of dense slabs of subducted oceanic lithosphere (8 –10), which are the most prominent density heterogeneities in the mantle (11, 12). The motions of the surface plates have also been attributed to the ...
Geology
Geology (from the Greek γῆ, gē, i.e. ""earth"" and -λoγία, -logia, i.e. ""study of, discourse"") is an earth science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change. Geology can also refer generally to the study of the solid features of any celestial body (such as the geology of the Moon or Mars).Geology gives insight into the history of the Earth by providing the primary evidence for plate tectonics, the evolutionary history of life, and past climates. Geology is important for mineral and hydrocarbon exploration and exploitation, evaluating water resources, understanding of natural hazards, the remediation of environmental problems, and for providing insights into past climate change. Geology also plays a role in geotechnical engineering and is a major academic discipline.