Formation of intracratonic basins by lithospheric shortening and phase changes: a case study from the ultra‐deep East Barents Sea basin     

Sébastien Gac  Ritske S. Huismans  Nina S. C. Simon  Yuri Y. Podladchikov  Jan Inge Faleide 《地学学报》2013,25(6):459-464

The origin of large subsidence in intracratonic basins is still under debate. We propose a new and self‐consistent model for the formation of those basins, where lithospheric shortening/buckling triggers metamorphism and densification of crustal mafic heterogeneities. We use a forward thermo‐mechanical finite element technique to evaluate this mechanism for the typical example of the East Barents Sea basin (EBB) where a very large and compensated subsidence, accommodating an up to 20‐km‐thick sediment succession, is observed. The lower crust in the dynamic model is modelled with petrologic‐consistent densities for a wet mafic gabbroic composition that depend on pressure and temperature taking into account dehydration at high PT conditions. The model successfully explains the main characteristics of the EBB, notably the large anomalous and fast subsidence during the Late Permian–Early Triassic, its present‐day geometry and the absence of a significant gravity anomaly.  相似文献   

Thermodynamics of plagioclase III: Spontaneous strain at the I\overline 1 - P\overline 1 phase transition in Ca-rich plagioclase     

Simon A. T. Redfern  Ann Graeme-Barber  Ekhard Salje 《Physics and Chemistry of Minerals》1988,16(2):157-163

The lattice parameters of anorthites An₉₈Ab₂ and An₁₀₀ have been measured from 22 to 1100 K. The spontaneous strain arising from the \(I\overline 1 - P\overline 1\) displacive transition in An₉₈ follows second order Landau behaviour. The spontaneous strain (? _s) couples quadratically to the order parameter (Q ⁰) with ? _s∝Q ⁰²∝(T _c ^* ?T) and T _c ^* =530 K in An₉₈. This is in contrast to the tricritical behaviour observed in pure anorthite. These observations are consistent with a Landau model for the free energy of Ca-rich plagioclases in which Al/Si order and Na content renormalize the fourth order coefficient.  相似文献   

Advances in modelling of snowpack processes utilizing remote sensing technology     

James L. Foster Dr.  Albert Rango Dr. 《GeoJournal》1989,19(2):185-192

Application of models over large areas requires enormous amounts of point data which are seldom available. As a result, the use of remote sensing to acquire data for these models becomes a practical alternative because from space areal measurements can be made over entire regions. Remote sensing data sets of snow are being studied and refined for input into energy balance, hydrological, and general circulation models. Snow influences the amount of solar energy retained and returned to space, the utilization of radiant energy in the hydrological cycle, and the atmospheric circulation by interacting with and modifying air masses. The continually evolving remote sensing technology will be used to provide a better understanding of how snow cover influences global climate and a better fundamental understanding of snow accumulation and ablation processes.  相似文献   

Observations of mid-troposhheric circulation from water vapour radiances of polar orbiting satellites     

M S Narayanan  P K Pal  P C Joshi  M Mali  Baby Simon 《Journal of Earth System Science》1989,98(3):247-254

Water vapour tracers can provide useful information on winds at ≈ 500mb by observing the 6·7μ radiances. This fills the data gap in the cloud motion winds provided by conventional meteorological geostationary satellites. There is no geostationary satellite at present over the Indian Ocean with 6·7μ imaging capability to provide mid-tropospheric winds. The potentials of 6·7μ radiances, available from polar orbiting satellites, for mid-tropospheric circulation features have been examined in this study. Tiros-N satellite data of May 1979 and ECMWF level-IIIb wind data were analysed to relate the radiances with the streamlines. We find that the radiances of 6·7μ from orbiting satellites agree well with the wind field.  相似文献   

Ultraviolet absorption cross-sections of chloro and chlorofluoro-methanes at stratospheric temperatures     

P. C. Simon  D. Gillotay  N. Vanlaethem-Meuree  J. Wisemberg 《Journal of Atmospheric Chemistry》1988,7(2):107-135

Absorption cross-sections of nine halomethanes (CCl₄, CHCl₃, CH₂Cl₂, CH₃Cl, CFCl₃, CF₂Cl₂, CF₃Cl, CHFCl₂, and CHF₂Cl), measured between 174 and 250 nm for temperatures ranging from 225 to 295 K, are presented with uncertainties ranging from 2 to 4% and compared with previous determinations made for comparable temperature ranges.The largest temperature effect which takes place near the absorption threshold, decreases the absorption cross-section up to 50% for highly chlorinated methanes, but is negligible for molecules highly stabilized by hydrogen and/or fluorine. Extrapolated values for temperatures of aeronomical interest are presented, as well as parametrical formulas which give absorption cross-section values for given wavelength and temperature ranges.  相似文献   

Theoretical background for the inversion of seismic waveforms including elasticity and attenuation   总被引：3，自引：0，他引：3  

Albert Tarantola 《Pure and Applied Geophysics》1988,128(1-2):365-399

To account for elastic and attenuating effects in the elastic wave equation, the stress-strain relationship can be defined through a general, anisotropic, causal relaxation function ^ijkl (x, ). Then, the wave equation operator is not necessarily symmetric (self-adjoint), but the reciprocity property is still satisfied. The representation theorem contains a term proportional to the history of strain. The dual problem consists of solving the wave equation withfinal time conditions and an anti-causal relaxation function. The problem of interpretation of seismic waveforms can be set as the nonlinear inverse problem of estimating the matter density (x) and all the functions ^ijkl (x, ). This inverse problem can be solved using iterative gradient methods, each iteration consisting of the propagation of the actual source in the current medium, with causal attenuation, the propagation of the residuals—acting as if they were sources—backwards in time, with anti-causal attenuation, and the correlation of the two wavefields thus obtained.  相似文献   

Discussion of ‘The Azuara impact structure (Spain): new insights from geophysical and geological investigations’ by K. Ernston and J. Fiebag     

Marc Aurell  Ángle González  A. Pérez  Joan Guimerà  Albert Casas  Ramon Salas 《International Journal of Earth Sciences》1993,82(4):750-755

  相似文献   

The reserves of extracted resources: Historical data     

Julian L. Simon  Guenter Weinrauch  Stephen Moore 《Natural Resources Research》1994,3(4):325-340

The available data on known reserves of extracted resources have not previously been tabulated and graphed. In this article we compile the reserves data in one place for the first time. This serves to (1) show the trends in the reserves series, (2) make the series available to others, and (3) place the reserves data in the context of price data for which longer series have been available, and with which they can now be seen to be consistent in both showing increasing availability rather than increasing scarcity.  相似文献   

A framework for coupling shoals and shallow embayments with main channels in numerical modeling of coastal plain estuaries     

Albert Y. Kuo  Kyeong Park 《Estuaries and Coasts》1995,18(2):341-350

A simple computational framework is developed to include shoals and shallow embayments (SSE) and their interaction with main channels in estuarine modeling. The scheme, treating SSE as temporary storage areas, accounts for the water and material exchanges between SSE and main channels as the tide rises and falls, and for the biogeochemical processes affecting nonconservative substances such as water-quality parameters in SSE. The scheme, because of its simple nature, can be easily incorporated into one-, two- or three-dimensional models of estuaries with substantial SSE. The concept and the model implementation of the scheme are explained using a vertical two-dimensional model of estuarine hydrodynamics and water quality. The model application to the tidal Rappahannock River, a western shore tributary of Chesapeake Bay, demonstrates the scheme is simple and physically reasonable, and the importance of SSE in estuarine modeling. The inclusion of SSE in a water-quality model not only provides a framework, for computing water-quality conditions therein but also accounts for the interaction between SSE and the main channel. It is shown that significant errors may result if the effects of SSE are not properly accounted for in modeling of an estuary with extensive SSE.  相似文献   

Multilayer Sampling in the Water-Table Region of a Sandy Aquifer     

Edward Kaplan  Sujit Banerjee  Daniel Ronen  Mordeckai Magaritz  Albert Machlin  Michael Sosnow  Eric Koglin 《Ground water》1991,29(2):191-198

  相似文献