FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W2062022995> ?p ?o ?g. }

• W2062022995 endingPage "156" @default.
• W2062022995 startingPage "139" @default.
• W2062022995 abstract "Formation of rifted continental margins is associated with localized thinning and breakup of the continental lithosphere, driven or accompanied by the ascent of the lithosphere– asthenosphere boundary. Thinning creates sharp density and viscosity contrasts and steep boundaries between cold deformed lithosphere and hot upwelling asthenosphere, thus providing conditions for the development of positive (asthenosphere) and negative (mantle lithosphere) Rayleigh–Taylor (RT) instabilities. The evolution of many continental margins (e.g. Newfoundland margin and Iberian margin) is characterized by slow spreading rates. This allows the RT instabilities to grow at the timescale of rifting. The impact of positive RT instabilities (asthenospheric upwelling) is well studied. The negative RT instabilities, associated with mantle downwelling, remain an overlooked factor. However, these instabilities should also affect the rift evolution, in particular, they may cause mantle thinning or thickening below the rift flanks. Our numerical experiments suggest that the ratio of the RT-growth rate to the extension rate controls the overall rift geometry and evolution. Even if the effect of negative RT instabilities is more important for slow extension rates of 2 5 mm year (Deborah number, De , 1), it is still significant for 2–3 times higher extension rates of 2 15 mm year (De , 10). The numerical experiments for extension rates of 2 15 mm year and mantle–asthenosphere density contrasts of 10–20 kg m demonstrate a number of structural similarities with continental margins characterized by low De (e.g. Flemish Cap and Galicia margin). In particular, rift asymmetry results from interplay between the RT instabilities and differential stretching at De , 1. Formation of interior basins occurs at De 1–3. The best correspondence with the observed geometry of rifted margins is obtained for chemical density contrast of 20 kg m and extension rate of 2 15 mm year, which is twice that of the averaged values inferred from the observations. This suggests that margins may initially (prebreakup stage) extend at higher rates than the average extension rates characterizing rift evolution. The influence of RT instabilities is strongly controlled by extension rate, density, rheology and thermal structure of the lithosphere; this implies that we need better constraints on these parameters from the observations. Continental margins result from rifting characterized by large coefficients of extension 4–5 , b , 15 (e.g. Bott 1971; Salvenson 1978; Cloetingh et al. 1982; Buck 1991). Rifting processes involve laterally variable thinning of ductile layers of different densities. If a denser layer (mantle lithosphere) is located on top of a lighter layer (asthenosphere), then the system is gravitationally unstable and may develop negative Rayleigh–Taylor (RT) instabilities. This possibility specifically refers to rifting, passive or active, where hot light asthenosphere ascends to the surface and replaces colder denser lithosphere. In most situations, normal lithospheric mantle is approximately 10–30 kg m denser than the underlying asthenospheric layer, basically due to its colder temperature but also due to compositional differences (e.g. Stacey 1992; O’Reilly et al. 2001; Poudjom Djomani et al. 2001; Turcotte & Schubert 2002). Some authors (e.g. Houseman et al. 1981) assume even much higher total density differences of up to 100 kg m. The density differences of the order of 20 kg m are commonly accepted for the Phanerozoic lithosphere, even though there is still a debate about whether it applies to the presumably Mg-rich and -depleted cratonic lithosphere. Irrespective, volumetric seismic velocities, which are generally considered as proxy for density, are systematically higher in the lithosphere mantle than in the asthenosphere. Depending on its viscosity the mantle lithosphere therefore has the potential to sink as the result of a RT instability (e.g. Houseman et al. 1981). The growth rate of the RT instabilities is directly proportional to the density contrast and inversely proportional to the thickness and the viscosity of the upper layer (if the viscosity of the lower layer is small). Depending on that, the instabilities may be rapid or slow compared to the tectonic deformation rates. In the first case, they will influence the rift evolution, but not in the second. The conditions when the RT instabilities are slow apply to the cases when the viscosity of the mantle lithosphere is higher than 10 Pa s, when the density contrast between the lithosphere From: KARNER, G. D., MANATSCHAL, G. & PINHEIRO, L. M. (eds) Imaging, Mapping and Modelling Continental Lithosphere Extension and Breakup. Geological Society, London, Special Publications, 282, 139–156. DOI: 10.1144/SP282.7 0305-8719/07/$15.00 # The Geological Society of London 2007. and the asthenosphere is small, or when the interface between the mantle and the asthenosphere remains flat (e.g. Houseman & Molnar 1997). This applies to oceanic and continental plates at normal conditions that infer smooth boundaries and smooth vertical temperature profiles and practical absence of lateral heat transport (e.g. prerift geotherm in Fig. 1a). Fig. 1. (a) Simplified cartoon showing the interaction between the asthenosphere and mantle lithosphere during rifting. Left: the mantle lithosphere below the rift flanks becomes gravitationally unstable owing to the negative density contrast with the hot asthenosphere and the loss of mechanical resistance resulting from lateral heat transfer from the asthenosphere below the rifted zone. The asthenosphere is positively unstable because of its positive density contrast with the embedding mantle lithosphere. As the viscosity of the mantle lithosphere is exponentially dependent on temperature, there is a relatively net ‘stability level’ that separates the regions of high viscosity from thermally weakened regions of low viscosity. These regions are subject to development of rapid RT instabilities. Right: simplified yield-stress prerift envelope of the continental lithosphere and typical prerift temperature profile. (b) Left: potential density contrast (reference density at 750 8C) and viscosity of olivine mantle, as function of temperature (left). Viscosity is shown for three representative values of the background strain rate (10, 10 and 10 s). Right: time until full detachment of the unstable mantle layer, as a function of initial layer thickness (olivine rheology), computed according to Conrad & Molnar (1999). The initial perturbation amplitude is w0. Note that for a normal depth–pressure–temperature profile of mantle lithosphere, the density contrast due to thermal expansion is nearly negated by the effect of compressibility (Turcotte & Schubert 2002). This is not the case of rifting when the mantle is heated without compensatory increase in pressure. E. BUROV 140" @default.
• W2062022995 created "2016-06-24" @default.
• W2062022995 creator A5076982872 @default.
• W2062022995 date "2007-01-01" @default.
• W2062022995 modified "2023-09-27" @default.
• W2062022995 title "The role of gravitational instabilities, density structure and extension rate in the evolution of continental margins" @default.
• W2062022995 cites W116101445 @default.
• W2062022995 cites W1565340041 @default.
• W2062022995 cites W1601684190 @default.
• W2062022995 cites W1977156689 @default.
• W2062022995 cites W1984633020 @default.
• W2062022995 cites W1985293475 @default.
• W2062022995 cites W1985371178 @default.
• W2062022995 cites W1991387574 @default.
• W2062022995 cites W1991830545 @default.
• W2062022995 cites W1994323983 @default.
• W2062022995 cites W1994635685 @default.
• W2062022995 cites W2013060894 @default.
• W2062022995 cites W2013092521 @default.
• W2062022995 cites W2020286870 @default.
• W2062022995 cites W2023781184 @default.
• W2062022995 cites W2033357906 @default.
• W2062022995 cites W2034688166 @default.
• W2062022995 cites W2034753142 @default.
• W2062022995 cites W2049907126 @default.
• W2062022995 cites W2051651324 @default.
• W2062022995 cites W2054562150 @default.
• W2062022995 cites W2072972330 @default.
• W2062022995 cites W2086934627 @default.
• W2062022995 cites W2093260086 @default.
• W2062022995 cites W2094826241 @default.
• W2062022995 cites W2104915444 @default.
• W2062022995 cites W2126039538 @default.
• W2062022995 cites W2126801202 @default.
• W2062022995 cites W2132964817 @default.
• W2062022995 cites W2138411584 @default.
• W2062022995 cites W2142222647 @default.
• W2062022995 cites W2146622027 @default.
• W2062022995 cites W2148674466 @default.
• W2062022995 cites W2164612341 @default.
• W2062022995 cites W2164687304 @default.
• W2062022995 cites W2775235778 @default.
• W2062022995 cites W4234440840 @default.
• W2062022995 doi "https://doi.org/10.1144/sp282.7" @default.
• W2062022995 hasPublicationYear "2007" @default.
• W2062022995 type Work @default.
• W2062022995 sameAs 2062022995 @default.
• W2062022995 citedByCount "17" @default.
• W2062022995 countsByYear W20620229952012 @default.
• W2062022995 countsByYear W20620229952013 @default.
• W2062022995 countsByYear W20620229952015 @default.
• W2062022995 countsByYear W20620229952016 @default.
• W2062022995 countsByYear W20620229952017 @default.
• W2062022995 countsByYear W20620229952018 @default.
• W2062022995 countsByYear W20620229952020 @default.
• W2062022995 countsByYear W20620229952022 @default.
• W2062022995 crossrefType "journal-article" @default.
• W2062022995 hasAuthorship W2062022995A5076982872 @default.
• W2062022995 hasConcept C121332964 @default.
• W2062022995 hasConcept C127313418 @default.
• W2062022995 hasConcept C13280743 @default.
• W2062022995 hasConcept C199360897 @default.
• W2062022995 hasConcept C207821765 @default.
• W2062022995 hasConcept C2776761751 @default.
• W2062022995 hasConcept C2778029271 @default.
• W2062022995 hasConcept C41008148 @default.
• W2062022995 hasConcept C57879066 @default.
• W2062022995 hasConceptScore W2062022995C121332964 @default.
• W2062022995 hasConceptScore W2062022995C127313418 @default.
• W2062022995 hasConceptScore W2062022995C13280743 @default.
• W2062022995 hasConceptScore W2062022995C199360897 @default.
• W2062022995 hasConceptScore W2062022995C207821765 @default.
• W2062022995 hasConceptScore W2062022995C2776761751 @default.
• W2062022995 hasConceptScore W2062022995C2778029271 @default.
• W2062022995 hasConceptScore W2062022995C41008148 @default.
• W2062022995 hasConceptScore W2062022995C57879066 @default.
• W2062022995 hasIssue "1" @default.
• W2062022995 hasLocation W20620229951 @default.
• W2062022995 hasOpenAccess W2062022995 @default.
• W2062022995 hasPrimaryLocation W20620229951 @default.
• W2062022995 hasRelatedWork W1970011760 @default.
• W2062022995 hasRelatedWork W1974193377 @default.
• W2062022995 hasRelatedWork W2003224676 @default.
• W2062022995 hasRelatedWork W2321343123 @default.
• W2062022995 hasRelatedWork W2935759653 @default.
• W2062022995 hasRelatedWork W3006712259 @default.
• W2062022995 hasRelatedWork W3105167352 @default.
• W2062022995 hasRelatedWork W3122615051 @default.
• W2062022995 hasRelatedWork W3130996217 @default.
• W2062022995 hasRelatedWork W3137601746 @default.
• W2062022995 hasVolume "282" @default.
• W2062022995 isParatext "false" @default.
• W2062022995 isRetracted "false" @default.
• W2062022995 magId "2062022995" @default.
• W2062022995 workType "article" @default.