Anisotropic Pn tomography of Turkey and adjacent regions
... Pn tomography has proven to be very useful to investigate the uppermost mantle velocity and anisotropic structure at local and regional scales (Hess 1964; Backus 1965; Hearn & Ni 1994; Hearn 1996, 1999). Large velocity contrast between crust and mantle confines propagation of Pn waves to the uppermo ...
... Pn tomography has proven to be very useful to investigate the uppermost mantle velocity and anisotropic structure at local and regional scales (Hess 1964; Backus 1965; Hearn & Ni 1994; Hearn 1996, 1999). Large velocity contrast between crust and mantle confines propagation of Pn waves to the uppermo ...
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... timations are in good agreement with the number and sizes of the Earth's theorized first supercontinents, Vaalbara and Ur. In our tectonophysical discussion of the formation of the lithospheric block structure, we analyze in detail the map of modern lithospheric plates [Bird, 2003] in combinatio ...
... timations are in good agreement with the number and sizes of the Earth's theorized first supercontinents, Vaalbara and Ur. In our tectonophysical discussion of the formation of the lithospheric block structure, we analyze in detail the map of modern lithospheric plates [Bird, 2003] in combinatio ...
orogenesis and ore deposits
... frequently with narrower, sharper downwarpingsunder load, hencemore frequent deformation and lesslofty mountains. Observations of sediments in the Precambrian shields indicate that break-down of rocks under weathering was less complete than in later times. Deformation and igneousactivity within orog ...
... frequently with narrower, sharper downwarpingsunder load, hencemore frequent deformation and lesslofty mountains. Observations of sediments in the Precambrian shields indicate that break-down of rocks under weathering was less complete than in later times. Deformation and igneousactivity within orog ...
Local modification of the lithosphere beneath the central and
... remains controversial. Detailed images of the lithosphere can provide key insights into this issue. Large-scale seismic tomography results show that high-velocity anomalies extend to deeper than 200 km beneath the central and western NCC, suggesting the presence of a thick cratonic mantle root in th ...
... remains controversial. Detailed images of the lithosphere can provide key insights into this issue. Large-scale seismic tomography results show that high-velocity anomalies extend to deeper than 200 km beneath the central and western NCC, suggesting the presence of a thick cratonic mantle root in th ...
Science
... Many dredged basalts from the Mid- ly, was suggested as the explanation of that they comprise a distinct, relatively uniform low-potassium variety of tho- Atlantic Ridge showed evidence of either the anomaly patterns (24). The high inleiitic basalt (16). Further study of rocks weathering or metamorp ...
... Many dredged basalts from the Mid- ly, was suggested as the explanation of that they comprise a distinct, relatively uniform low-potassium variety of tho- Atlantic Ridge showed evidence of either the anomaly patterns (24). The high inleiitic basalt (16). Further study of rocks weathering or metamorp ...
42. The New England Seamounts
... phase of volcanic activity at Vogel Seamount should have occurred about 11 m.y. before the corresponding activity at Nashville Seamount. As can be seen in Figure 1, the available data neither demonstrate nor preclude such an age difference. The volcaniclastic breccias recovered at the Leg 43 sites a ...
... phase of volcanic activity at Vogel Seamount should have occurred about 11 m.y. before the corresponding activity at Nashville Seamount. As can be seen in Figure 1, the available data neither demonstrate nor preclude such an age difference. The volcaniclastic breccias recovered at the Leg 43 sites a ...
The thermal effects of steady-state slab
... of 75 –90 mW/m2 is observed, with local variations attributed to varying crustal heat production [27,28]. The reduced (deep crust/mantle) heat flow for all regions is 55 –65 mW/m2 [19,27,28], suggesting that there is little variation in the deep thermal structure for the entire Cascadia backarc. One ...
... of 75 –90 mW/m2 is observed, with local variations attributed to varying crustal heat production [27,28]. The reduced (deep crust/mantle) heat flow for all regions is 55 –65 mW/m2 [19,27,28], suggesting that there is little variation in the deep thermal structure for the entire Cascadia backarc. One ...
Glossary of Terms
... upper mantle with a peridotite composition (sub-continental lithospheric mantle). Lithospheric Architecture: The large-scale structure of the continental lithosphere, comprising a mosaic of discrete domains. Domain boundaries are particularly significant sites for the localisation of later tectonic ...
... upper mantle with a peridotite composition (sub-continental lithospheric mantle). Lithospheric Architecture: The large-scale structure of the continental lithosphere, comprising a mosaic of discrete domains. Domain boundaries are particularly significant sites for the localisation of later tectonic ...
Geography Revision - Geography at InterHigh
... Which of these places go with each types of plate margins? What can happen along any of these faults? (not pleasant!) ...
... Which of these places go with each types of plate margins? What can happen along any of these faults? (not pleasant!) ...
93. Lee, C. - Squarespace
... of the terrestrial compositional spectrum. However, most subduction zone magmas erupted or sampled at the surface are basalt-andesitic to andesitic and hence have higher Si contents. Endmember hypotheses for the origin of andesites are: (1) direct melting of the mantle at water-saturated conditions, ...
... of the terrestrial compositional spectrum. However, most subduction zone magmas erupted or sampled at the surface are basalt-andesitic to andesitic and hence have higher Si contents. Endmember hypotheses for the origin of andesites are: (1) direct melting of the mantle at water-saturated conditions, ...
Lithospheric thickness under the Dinarides
... surface. Previous investigations mapped two strong reflectors, one shallow, which was interpreted as the boundary between sedimentary cover and crystalline basement and significantly deeper one ascribed to Mohorovičić discontinuity. Results indicate a relatively narrow belt of thicker crust (>40km) fo ...
... surface. Previous investigations mapped two strong reflectors, one shallow, which was interpreted as the boundary between sedimentary cover and crystalline basement and significantly deeper one ascribed to Mohorovičić discontinuity. Results indicate a relatively narrow belt of thicker crust (>40km) fo ...
"lost Inca Plateau": cause of flat subduction - Archimer
... magnetic anomaly data older than Anomaly 13 on the Pacific and Nazca plates, it was possible to obtain reconstructions which satisfy all fracture zone and magnetic anomaly constraints. Thus, four oceanic plateaus are restored to conjugate on axis positions at 34 Ma and 43 Ma (Fig. 1 B,C). A modern a ...
... magnetic anomaly data older than Anomaly 13 on the Pacific and Nazca plates, it was possible to obtain reconstructions which satisfy all fracture zone and magnetic anomaly constraints. Thus, four oceanic plateaus are restored to conjugate on axis positions at 34 Ma and 43 Ma (Fig. 1 B,C). A modern a ...
Magmatic constraints on geodynamic models of subduction in the
... significantly later than the end of basin closure and the onset of continental collision along the Inner Carpathian arc that is thought to have taken place during the Miocene (9–5 Ma). Migration of magmatic activity from NW to SE along the arc may be explained by a corresponding migration of the mag ...
... significantly later than the end of basin closure and the onset of continental collision along the Inner Carpathian arc that is thought to have taken place during the Miocene (9–5 Ma). Migration of magmatic activity from NW to SE along the arc may be explained by a corresponding migration of the mag ...
Powerpoint Presentation Physical Geology, 10/e
... Geologic & Biologic Activity at the Ridges • Geologic Activity at the Ridges – Shallow focus (0-20 km) earthquakes – High heat flow decreasing away from the ridge – Basaltic eruptions – Hot springs (Black smokers) ...
... Geologic & Biologic Activity at the Ridges • Geologic Activity at the Ridges – Shallow focus (0-20 km) earthquakes – High heat flow decreasing away from the ridge – Basaltic eruptions – Hot springs (Black smokers) ...
Plate Tectonics
... ■ Hands-on Activities ■ Meeting Individual Needs (Extension and Intervention) ■ Transparency Activities A teacher support and planning section including ■ Content Outline of the chapter ...
... ■ Hands-on Activities ■ Meeting Individual Needs (Extension and Intervention) ■ Transparency Activities A teacher support and planning section including ■ Content Outline of the chapter ...
How does the challenge differ between plate boundaries, plate
... Mountain building by continental collision produced boundary zone extending 1000’s of km northward from the nominal plate boundary at the Himalayan front. ...
... Mountain building by continental collision produced boundary zone extending 1000’s of km northward from the nominal plate boundary at the Himalayan front. ...
On the thermal gradient in the Earth`s deep interior
... FeO = 9.48, SiO2 = 45.8 (wt %), approximately describes a peridotite bulk composition. The dynamic transport equations for a compressible flow can be found in Schubert et al. (2001). The details of the numerical solution are given in Tirone et al. (2009). Viscosity is set to (1 × 1022 Pa s), thermal ...
... FeO = 9.48, SiO2 = 45.8 (wt %), approximately describes a peridotite bulk composition. The dynamic transport equations for a compressible flow can be found in Schubert et al. (2001). The details of the numerical solution are given in Tirone et al. (2009). Viscosity is set to (1 × 1022 Pa s), thermal ...
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.