Pennsylvanian carbonate platforms adjacent to deltaic systems in an active marine foreland basin (Escalada Fm., Cantabrian Zone,NW Spain)

The Pennsylvanian marine foreland basin of the Cantabrian Zone (NW Spain) is characterized by the unique development of kilometre‐size and hundred‐metre‐thick carbonate platforms adjacent to deltaic systems. During Moscovian time, progradational clastic wedges fed by the orogen comprised proximal alluvial conglomerates and coal‐bearing deltaic sequences to distal shelfal marine deposits associated with carbonate platforms (Escalada Fm.) and distal clay‐rich submarine slopes. A first phase of carbonate platform development (Escalada I, upper Kashirian‐lower Podolskian) reached a thickness of 400 m, nearly 50 km in width and developed a distal high‐relief margin facing a starved basin, nearly 1000‐m deep. Carbonate slope clinoforms dipped up to 30° and consisted of in situ microbial boundstone, pinching out downslope into calciturbidites, argillaceous spiculites and breccias. The second carbonate platform (Escalada II, upper Podolskian‐lower Myachkovian) developed beyond the previous platform margin, following the basinward progradation of siliciclastic deposits. Both carbonate platforms include: (1) a lower part composed of siliciclastic‐carbonate cyclothems characterized by coated‐grain and ooid grainstones; and (2) a carbonate‐dominated upper part, composed of tabular and mound‐shaped wackestone and algal‐microbial boundstone strata alternating at the decametre scale with skeletal and coated‐grain grainstone beds. Carbonate platforms initiated in distal sectors of the foreland marine shelf during transgressions, when terrigenous sediments were stored in the proximal part, and developed further during highstands of 3rd‐order sequences in a high‐subsidence context. During the falling stage and lowstand systems tracts, deltaic systems prograded across the shelf burying the carbonate platforms. Key factors involved in the development of these unique carbonate platforms in an active foreland basin are: (1) the large size of the marine shelf (approaching 200 km in width); (2) the subsidence distribution pattern across the marine shelf, decreasing from proximal shoreline to distal sectors; (3) Pennsylvanian glacio‐eustacy affecting carbonate lithofacies architecture; and (4) the environmental conditions optimal for fostering microbial and algal carbonate factories.     

Plane-symmetric mesonic viscous fluid cosmological model

Exact nonstatic solutions to Einstein field equations are obtained for the plane symmetric spacetime filled with viscous perfect fluid in the presence of attractive scalar fields. Some physical and geometrical properties of the model are studied. The solutions characterize strong interaction of elementary particles.     

LRS Bianchi type V vacuum cosmological solution in Brans-Dicke theory

In this note a new solution of the BD field equations, for a Bianchi type V space-time, is obtained. The solution has its general relativistic analogue. Some properties of the solution are also discussed.     

Exact Bianchi type VI0 cosmological solutions with matter in Brans-Dicke theory

We present an exact solution of the Brans-Dicke equations for cosmological models of Bianchi type VI₀ with stiff matter. The solution represents anisotropic universe which has its analogy in Einstein's theory. The corresponding result for a plane symmetry Bianchi type I model is obtained as a special case.     

Thermal and mass diffusion on MHD natural convective flow of a rarefied gas along vertical porous plate

The flow of an electrically conducting incompressible rarefied gas due to the combined buoyancy effects of thermal and mass diffusion past an infinite vertical porous plate with constant suction has been studied in the presence of uniform transverse magnetic field. The problem has been solved for velocity, temperature, and concentration fields. It has been observed that mean velocity and the mean temperature are affected by the Grashof numbersG ₁ andG ₂, the slip parameterh ₁, temperature jump coefficienth ₂, concentration jump coefficienth ₃ and magnetic field parameterM. The amplitude and the phase of skin-friction and the rate of heat transfer are affected by frequency in addition to the above parameters. They are shown graphically. The numerical values of the mean skin-friction and the mean rate of heat transfer are also tabulated.     

Heat and mass transfer on MHD heat generating flow through a porous medium in a rotating fluid

The problem of the free-convection flow of a viscous heat generating fluid through porous media in a rotating frame of reference is considered for the case when a strong magnetic field is imposed in a direction which is perpendicular to the free-stream and makes an angle to the vertical direction. Analytical expressions for the velocity field and temperature are given, and the influences of the various parameters on the velocity field are discussed.     

On steady plane rotating hydromagnetic flows

We consider the steady plane rotating, constantly inclined magnetohydrodynamic flows of a viscous incompressible fluid when the velocity magnitude is constant on each individual stream line. Hodograph transformation is employed and resulting partial differential equations are used to obtain the solution and the geometries for these flows whenJ0 andJ=0.     

A formal framework for the representation of stack-based terrains

This paper presents a formal framework for the representation of three-dimensional geospatial data and the definition of common geographic information system (GIS) spatial operations. We use the compact stack-based representation of terrains (SBRT) in order to model geological volumetric data, both at the surface and subsurface levels, thus preventing the large storage requirements of regular voxel models. The main contribution of this paper is fitting the SBRT into the geo-atom theory in a seamless way, providing it with a sound formal geographic foundation. In addition we have defined a set of common spatial operations on this representation using the tools provided by map algebra. More complex geoprocessing operations or geophysical simulations using the SBRT as representation can be implemented as a composition of these fundamental operations. Finally a data model and an implementation extending the coverage concept provided by the Geography Markup Language standard are suggested. Geoscientists and GIS professionals can take advantage of this model to exchange and reuse geoinformation within a well-specified framework.     

Tree-ring analysis of teak (Tectona grandis L.F.) in central India and its relationship with rainfall and moisture index

Tree-ring-width index chronologies of teak (Tectona grandis L.F.) from three sites in central India have been studied for their dendroclimatic potential. The existence of good correlation among the three site chronologies indicates the influence of common forcing factor to the tree growth of the region. Tree growth and climate relationship based on correlation analysis revealed the important contribution of moisture index and rainfall rather than the direct influence of the temperature on tree growth during different seasons. Significant positive relationship of moisture index and rainfall during the monsoon months as well as on the annual scale with tree-ring width variations over the region indicates the important role of moisture availability at the root zone. The results suggest that the teak tree-ring chronologies can be used as high resolution proxy for past precipitation and moisture level in the environment.