1 The role of the mantle wedge in subduction zone dynamics and
... Subduction zones are the dominant tectonic features of the Earth. They form the location of the major underthrusting earthquakes, explosive arc volcanism and are the only sites of deep earthquakes in the Earth’s mantle. The role of subduction zones in the plate tectonic framework is reasonably well ...
... Subduction zones are the dominant tectonic features of the Earth. They form the location of the major underthrusting earthquakes, explosive arc volcanism and are the only sites of deep earthquakes in the Earth’s mantle. The role of subduction zones in the plate tectonic framework is reasonably well ...
Mantle flow through the Northern Cordilleran slab window revealed
... the slab window triggered upwelling of anhydrous mantle and displacement of the hydrous mantle wedge, which had developed during extensive early Cenozoic arc and backarc volcanism in western Canada. High heat flow throughout the western Canadian Cordillera is broadly coincident with the field of int ...
... the slab window triggered upwelling of anhydrous mantle and displacement of the hydrous mantle wedge, which had developed during extensive early Cenozoic arc and backarc volcanism in western Canada. High heat flow throughout the western Canadian Cordillera is broadly coincident with the field of int ...
Provenance characteristics of the Brumunddal sandstone in the Oslo
... common accessory mineral grains in the sandstone. U-Pb dating of detrital zircon from a sample of the Brumunddal sandstone by LAM-ICPMS gives a range of ages from (rare) late Archaean ages to Permian (283±4 Ma). The age and initial εHf pattern of zircons in the sediment match the main rock- forming ...
... common accessory mineral grains in the sandstone. U-Pb dating of detrital zircon from a sample of the Brumunddal sandstone by LAM-ICPMS gives a range of ages from (rare) late Archaean ages to Permian (283±4 Ma). The age and initial εHf pattern of zircons in the sediment match the main rock- forming ...
The continent marginal crust characteristic of nothern South China
... boundary (COB) with previous studies at western part of the Dongsha Island, but we suggest the position of the COB in the eastern part of the Dongsha Island should be moved landward to near the end of continental slop. By our result, we could not recognize the characteristic of the continent-ocean t ...
... boundary (COB) with previous studies at western part of the Dongsha Island, but we suggest the position of the COB in the eastern part of the Dongsha Island should be moved landward to near the end of continental slop. By our result, we could not recognize the characteristic of the continent-ocean t ...
1.8 Billion Years of Detrital Zircon Recycling Calibrates a
... any older strata and so to narrow down potential sources the younger portion of the age spectrum is subdivided into 750–600 Ma, 600–500 Ma, 500–350 Ma, and 350–200 Ma (Fig 4). The Upper Cretaceous spectrum has peaks ranging from 600–350 Ma that only overlap comprehensively with the Upper Mississippi ...
... any older strata and so to narrow down potential sources the younger portion of the age spectrum is subdivided into 750–600 Ma, 600–500 Ma, 500–350 Ma, and 350–200 Ma (Fig 4). The Upper Cretaceous spectrum has peaks ranging from 600–350 Ma that only overlap comprehensively with the Upper Mississippi ...
Article
... any older strata and so to narrow down potential sources the younger portion of the age spectrum is subdivided into 750–600 Ma, 600–500 Ma, 500–350 Ma, and 350–200 Ma (Fig 4). The Upper Cretaceous spectrum has peaks ranging from 600–350 Ma that only overlap comprehensively with the Upper Mississippi ...
... any older strata and so to narrow down potential sources the younger portion of the age spectrum is subdivided into 750–600 Ma, 600–500 Ma, 500–350 Ma, and 350–200 Ma (Fig 4). The Upper Cretaceous spectrum has peaks ranging from 600–350 Ma that only overlap comprehensively with the Upper Mississippi ...
Seismic velocity structure of the rifted margin of the eastern Grand
... seismometers (OBSs). At the landward side, we imaged a crustal thickness of 27 km in Flemish Pass and beneath Beothuk Knoll, which is thinner than the 35-km-thick crust of the central Grand Banks. We therefore assume that the eastern rim of the Grand Banks stretched uniformly by 25%. Farther seaward ...
... seismometers (OBSs). At the landward side, we imaged a crustal thickness of 27 km in Flemish Pass and beneath Beothuk Knoll, which is thinner than the 35-km-thick crust of the central Grand Banks. We therefore assume that the eastern rim of the Grand Banks stretched uniformly by 25%. Farther seaward ...
Roberts et al., 2013, Basin Modeling
... a simple but powerful technique to employ as the fundamental requirement is simply a 2D or 3D model (cross-section or maps) of the post-break-up margin stratigraphy. •• 2d/3d syn-kinematic flexural backstripping. Post-break-up backstripping is, indeed, a straightforward technique to employ, but, at ...
... a simple but powerful technique to employ as the fundamental requirement is simply a 2D or 3D model (cross-section or maps) of the post-break-up margin stratigraphy. •• 2d/3d syn-kinematic flexural backstripping. Post-break-up backstripping is, indeed, a straightforward technique to employ, but, at ...
Released Items from the ATLAST Plate Tectonics Teacher Assessment
... reasons other than plate interactions (some volcanoes occur distant from plate boundaries as a result of hot spots)] H. The rock that makes up plates is slowly being formed at some plate boundaries and returned to Earth’s interior at other plate boundaries. This means that Earth is not changing in s ...
... reasons other than plate interactions (some volcanoes occur distant from plate boundaries as a result of hot spots)] H. The rock that makes up plates is slowly being formed at some plate boundaries and returned to Earth’s interior at other plate boundaries. This means that Earth is not changing in s ...
Thermal and petrophysical characterization of the lithospheric
... heat flow and crustal seismic data show LAB depth varying from more than 130 km beneath the Pyrenees to less than 70 km beneath the western Mediterranean basins (Zeyen and Fernandez, 1994; Ayala et al., 1996, 2003; Roca et al., 2004). All these models however are based on a pure thermal approach in w ...
... heat flow and crustal seismic data show LAB depth varying from more than 130 km beneath the Pyrenees to less than 70 km beneath the western Mediterranean basins (Zeyen and Fernandez, 1994; Ayala et al., 1996, 2003; Roca et al., 2004). All these models however are based on a pure thermal approach in w ...
Chapter 16. Noble Gas Isotopes
... characterized by low ratios and low abundances . The critical issues are when and how the 'primordial' noble gases entered the Earth , where they are stored and whether transport is always outwards and immediate upon melting, as often assumed. It is therefore important to understand the noble-gas bu ...
... characterized by low ratios and low abundances . The critical issues are when and how the 'primordial' noble gases entered the Earth , where they are stored and whether transport is always outwards and immediate upon melting, as often assumed. It is therefore important to understand the noble-gas bu ...
Crust and upper mantle discontinuity structure beneath eastern
... root appears to be greater than is required for local isostatic compensation of the heavily eroded topography [James et al., 1968; McNutt, 1980]. Data from the MOMA array allow us to systematically investigate crustal thickness and isostasy in the northern Appalachians. The MOMA array also provides ...
... root appears to be greater than is required for local isostatic compensation of the heavily eroded topography [James et al., 1968; McNutt, 1980]. Data from the MOMA array allow us to systematically investigate crustal thickness and isostasy in the northern Appalachians. The MOMA array also provides ...
Origins of the lower crustal reflectivity in the L¨utzow
... erosion. The adjacent Rayner Complex was once believed to have late-Proterozoic ages of 700–800 Ma (e.g., Sheraton et al., 1987); however, Shiraishi et al. (1997) re-investigated the metamorphic rock ages by zircon dating (SHRIMP) and determined the western part of the Rayner Complex as PanAfrican ( ...
... erosion. The adjacent Rayner Complex was once believed to have late-Proterozoic ages of 700–800 Ma (e.g., Sheraton et al., 1987); however, Shiraishi et al. (1997) re-investigated the metamorphic rock ages by zircon dating (SHRIMP) and determined the western part of the Rayner Complex as PanAfrican ( ...
Plate motions, Andean orogeny, and volcanism above the
... Tectonic forces balance everywhere on Earth and this naturally includes the Nazca trench and the Andean belt. As a result, mountain belts, and more generally backarc regions (Lallemand et al., 2008), can be regarded as dynamometers: their geometry and kinematics provide a straightforward tool to me ...
... Tectonic forces balance everywhere on Earth and this naturally includes the Nazca trench and the Andean belt. As a result, mountain belts, and more generally backarc regions (Lallemand et al., 2008), can be regarded as dynamometers: their geometry and kinematics provide a straightforward tool to me ...
22_Lectures_PPT
... Earth’s internal structure • The concept of continental drift and how it led to the theory of plate tectonics • Plate motion and how it impacts the Earth’s surface • Where earthquakes occur and their association with the plate tectonic model ...
... Earth’s internal structure • The concept of continental drift and how it led to the theory of plate tectonics • Plate motion and how it impacts the Earth’s surface • Where earthquakes occur and their association with the plate tectonic model ...
TROPICS Continent-Building in Costa Rica
... When compared to the other terrestrial planets, Earth’s continents, large areas of thick silica-rich (“granitic”) crust, are unique. Understanding the mechanical (accretion) and chemical (differentiation) processes of continent formation, and whether there has been secular change are fundamental pro ...
... When compared to the other terrestrial planets, Earth’s continents, large areas of thick silica-rich (“granitic”) crust, are unique. Understanding the mechanical (accretion) and chemical (differentiation) processes of continent formation, and whether there has been secular change are fundamental pro ...
Unconventional Isotopes and Approaches
... with a mean annual temperature of ~ 30˚C. But was it that hot in the Pliocene? Passey et al. (2010) applied clumped isotope geothermometry to paleosol carbonates the Turkana Basin. They first demonstrated that temperatures calculated from ∆47 in modern soil carbonates did in fact reflect the climate ...
... with a mean annual temperature of ~ 30˚C. But was it that hot in the Pliocene? Passey et al. (2010) applied clumped isotope geothermometry to paleosol carbonates the Turkana Basin. They first demonstrated that temperatures calculated from ∆47 in modern soil carbonates did in fact reflect the climate ...
Weakness of the lower continental crust: a condition for
... the top of the lower crust. In addition to being zones of potential decoupling, crustal low-viscosity zones are avenues for lateral crustal flow, a process that is often referred to as crustal escape (e.g., eastern Tibetan Plateau). The third process addressed here, crustal uplift, is mainly found i ...
... the top of the lower crust. In addition to being zones of potential decoupling, crustal low-viscosity zones are avenues for lateral crustal flow, a process that is often referred to as crustal escape (e.g., eastern Tibetan Plateau). The third process addressed here, crustal uplift, is mainly found i ...
Seismic imaging of a hot upwelling beneath the British Isles
... The Iceland plume has had an important influence on vertical motions in the North Atlantic. The convecting mantle in this region contains a large-scale low-velocity seismic anomaly, which correlates with a long-wavelength gravity high and bathymetric feature. This suggests that an arm of plume mater ...
... The Iceland plume has had an important influence on vertical motions in the North Atlantic. The convecting mantle in this region contains a large-scale low-velocity seismic anomaly, which correlates with a long-wavelength gravity high and bathymetric feature. This suggests that an arm of plume mater ...
Mantle temperature control on composition of arc magmas along the
... south to north along the CKD. Although primitive basalts occur in all localities, the range of primitive rock compositions increases toward the slab edge so that their mean and maximum SiO2 and Na2O contents increase and MgO, FeO, TiO2, and CaO decrease. Many primitive rocks from Shiveluch volcano a ...
... south to north along the CKD. Although primitive basalts occur in all localities, the range of primitive rock compositions increases toward the slab edge so that their mean and maximum SiO2 and Na2O contents increase and MgO, FeO, TiO2, and CaO decrease. Many primitive rocks from Shiveluch volcano a ...
Tectonic controls on the nature of large silicic calderas in volcanic arcs
... regions of local extension (Table 2). Of the calderas with rhyolitic eruptions, however, 77% are located in extensional regimes. As for backarc stress regimes (Table 1), which we assume to characterize the overall stress state of the arc, the lack of calderas in arcs with the most extension (backarc ...
... regions of local extension (Table 2). Of the calderas with rhyolitic eruptions, however, 77% are located in extensional regimes. As for backarc stress regimes (Table 1), which we assume to characterize the overall stress state of the arc, the lack of calderas in arcs with the most extension (backarc ...
Rudnick and Lee.fm - Cin
... from conductive to adiabatic thermal gradient; and (2) the transition from mechanical coupling with the rigid overlying plate to convective flow in the underlying asthenospheric or convecting mantle. Thus we use the terms “convecting mantle” and “asthenospheric mantle” synonymously. Inasmuch as we a ...
... from conductive to adiabatic thermal gradient; and (2) the transition from mechanical coupling with the rigid overlying plate to convective flow in the underlying asthenospheric or convecting mantle. Thus we use the terms “convecting mantle” and “asthenospheric mantle” synonymously. Inasmuch as we a ...
Science
... of the generally low recovery. In young basement sections, core recovery averages about 20 percent and is biased toward massive units. However, recent drilling in old oceanic crust at sites 417 and 418 resulted in much higher recoveries (average about 70 percent), providing for the first time a fair ...
... of the generally low recovery. In young basement sections, core recovery averages about 20 percent and is biased toward massive units. However, recent drilling in old oceanic crust at sites 417 and 418 resulted in much higher recoveries (average about 70 percent), providing for the first time a fair ...
The generation of plate tectonics from mantle convection. Earth and
... currence of such convection in the Earth’s mantle has been postulated since at least the 1930s [1^3], and one of the primary motivations for its study was to explain Continental Drift, which, after decades of oblivion, was revived and revised as the theory of Plate Tectonics. Plate Tectonics has bee ...
... currence of such convection in the Earth’s mantle has been postulated since at least the 1930s [1^3], and one of the primary motivations for its study was to explain Continental Drift, which, after decades of oblivion, was revived and revised as the theory of Plate Tectonics. Plate Tectonics has bee ...
A petrologic case for Eocene slab break
... which have either never tried to explain it (model 4), or have instead interpreted melting to result from less radical, shallower level tectonic processes coupled with local heat sources (models 1–3). Extensive melts eradicated most prior Greater Himalayan high- and/or ultrahighP history, except in ...
... which have either never tried to explain it (model 4), or have instead interpreted melting to result from less radical, shallower level tectonic processes coupled with local heat sources (models 1–3). Extensive melts eradicated most prior Greater Himalayan high- and/or ultrahighP history, except in ...
Supercontinent
In geology, a supercontinent is the assembly of most or all of the Earth's continental blocks or cratons to form a single large landmass. However, the definition of a supercontinent can be ambiguous. Many tectonicists such as P.F. Hoffman (1999) use the term ""supercontinent"" to mean ""a clustering of nearly all continents"". This definition leaves room for interpretation when labeling a continental body and is easier to apply to Precambrian times. Using the first definition provided here, Gondwana (aka Gondwanaland) is not considered a supercontinent, because the landmasses of Baltica, Laurentia and Siberia also existed at the same time but physically separate from each other. The landmass of Pangaea is the collective name describing all of these continental masses when they were in a close proximity to one another. This would classify Pangaea as a supercontinent. According to the definition by Rogers and Santosh (2004), a supercontinent does not exist today. Supercontinents have assembled and dispersed multiple times in the geologic past (see table). The positions of continents have been accurately determined back to the early Jurassic. However, beyond 200 Ma, continental positions are much less certain.