Results 131 to 140 of about 377 (180)
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Geology, 1981
Diapiric ascent is often assumed to occur in a mantle with a viscosity of order 10^(21) P, the value estimated from glacial rebound studies. Segregation of melt from residual crystals en route is then a necessary consequence of the slow ascent velocity. The temperatures and stresses associated with diapirs, however, are much greater than those involved
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Diapiric ascent is often assumed to occur in a mantle with a viscosity of order 10^(21) P, the value estimated from glacial rebound studies. Segregation of melt from residual crystals en route is then a necessary consequence of the slow ascent velocity. The temperatures and stresses associated with diapirs, however, are much greater than those involved
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Diapirs, Intrusions and Wedges
1989Various kinds of diapirs, intrusions and wedges are widely and commonly reported from glaciogenic sequences. Intrusive structures range in lateral size from only a few cm to > 100 m (fig. 1-4) and may have vertical dimensions of several lOs of m. Intrusive structures rarely give rise to distinctive or noticeable landforms, but they may dominate the ...
James S. Aber +2 more
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Diapiric penetration with melting
Physics of the Earth and Planetary Interiors, 1984Abstract We consider a series of problems in which a solid or an immiscible fluid body melts its way through a solid medium. Both internal heat generation and viscous heating are considered. We hypothesize that the melted medium is confined to a thin squeeze film on the upstream portion of the body and that the lubrication approximation is valid in ...
Steven H. Emerman, Donald L. Turcotte
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DIAPIRISM IN THE ADELAIDE GEOSYNCLINE
The APPEA Journal, 1965Approximately 20,000 feet of the Willouran Callanna Beds were deposited under shallow-water conditions in the western zone of the Adelaide Geosyncline. Diapirs were produced by the lower Callanna sequences. The initiation of diapiric growth is considered to be structural, but isostasy is thought to have played a subsequent role in the rise and ...
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Petroleum Geoscience, 2019
We use a 2D forward finite-element model to explore how a laterally continuous permeable bed impacts the geological evolution and the geomechanical properties of a salt basin. We show that a permeable bed tilted by rise of a salt diapir substantially increases pore pressure in sediments near the diapir through hydraulically connecting ...
Mahdi Heidari +3 more
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We use a 2D forward finite-element model to explore how a laterally continuous permeable bed impacts the geological evolution and the geomechanical properties of a salt basin. We show that a permeable bed tilted by rise of a salt diapir substantially increases pore pressure in sediments near the diapir through hydraulically connecting ...
Mahdi Heidari +3 more
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Journal of Structural Geology, 1981
Abstract The diapirs of Northern Tunisia, composed mainly of evaporitic Triassic material, are the result of a complex evolution initiated by local basement movements of NNE-SSW faults, which at the end of the Early Cretaceous. This first uplift, occurring during a period without any folding of the sedimentary series, is purely halokinetic.
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Abstract The diapirs of Northern Tunisia, composed mainly of evaporitic Triassic material, are the result of a complex evolution initiated by local basement movements of NNE-SSW faults, which at the end of the Early Cretaceous. This first uplift, occurring during a period without any folding of the sedimentary series, is purely halokinetic.
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The identification of granitic diapirs
Journal of the Geological Society, 1990Diapirism is a themomechanically viable ascent mechanism for granitic magmas. However there is very little direct evidence of actual granite diapirs. Many of the characteristics we may expect to use to determine ascent mechanisms are destroyed by changes in the shapes of intrusions resulting from the interaction of buoyancy and tectonic forces during ...
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Journal of Structural Geology, 1998
Abstract Six parameters shape the geometry of passive diapirs associated with stiff overburden: rates of salt supply ( S ′); dissolution ( D ′; sediment accumulation ( A ′); erosion ( Er′ ); extension ( E ′); and shortening ( Sh′ ). These parameters change in space and time, and hence influence the geometry of the structure as it forms.
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Abstract Six parameters shape the geometry of passive diapirs associated with stiff overburden: rates of salt supply ( S ′); dissolution ( D ′; sediment accumulation ( A ′); erosion ( Er′ ); extension ( E ′); and shortening ( Sh′ ). These parameters change in space and time, and hence influence the geometry of the structure as it forms.
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2019
Abstract We develop large strain, transient evolutionary geomechanical models of salt extensional systems to study possible controls on styles of diapir rise and fall. We examine extension rates of 1 and 2 km/m.y., baselevel rise rates of 1km/5m.y. and 1km/3m.y. and basement slopes of 0°, 1°, and 2°. We find that high sedimentation rates
Maria A. Nikolinakou +3 more
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Abstract We develop large strain, transient evolutionary geomechanical models of salt extensional systems to study possible controls on styles of diapir rise and fall. We examine extension rates of 1 and 2 km/m.y., baselevel rise rates of 1km/5m.y. and 1km/3m.y. and basement slopes of 0°, 1°, and 2°. We find that high sedimentation rates
Maria A. Nikolinakou +3 more
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Comment and Reply on ‘Rise of deep diapirs’
Geology, 1981Basaltic magmas apparently separate from their source region pressures of the order of 30 kb. In a convecting mantle it is reasonable to suppose that melting begins in the ascending limb of a convection cell as material is brought across the solidus.
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