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A review of the Lower - lowermost Upper Jurassic facies and stratigraphy of the Jaisalmer Basin, western Rajasthan, India

Pandey D., Choudhary S., Bahadur T., Swami N., Poonia D., Sha J.

Volumina Jurassica

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2012

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Vol. 10, no. 1

61--82

EN

The Lower - lowermost Upper Jurassic (up to Oxfordian) sedimentary succession of the Jaisalmer Basin on the Rajasthan Shelf is characterized by gradual lateral and rapid temporal facies variations, the existence of condensed sequences in certain horizons, and rich and highly diverse faunal contents. Lithostratigraphically, these Jurassic rocks of the basin have been grouped into the Lathi and Jaisalmer formations and the lower part of the Baisakhi Formation. The facies consist of (i) cross-bedded medium- to coarse-grained sandstone, (ii) cross-bedded to thinly laminated silt to fine-grained sandstone, (iii) silty marl, (iv) calcareous mud- to grainstone and sandy rudstone, (v) thinly laminated carbonaceous shale and (vi) conglomerate. These represent fluvial, floodplain, lacustrine, protected marginal marine, and shoreface to shelf environments. There are several marker units, which allow the making of intrabasinal lithostratigraphic correlations; however, a lack of knowledge of the detailed stratigraphic successions within individual lithostratigraphic units makes difficult a precise intra-basinal stratigraphic correlation. The present review provides a summary of the lithostratigraphy established by previous workers on the Lower - lowermost Upper Jurassic (up to Oxfordian) rocks of the Jaisalmer Basin, incorporating additional data, with a detailed stratigraphic succession within each lithostratigraphic unit, and more faunal elements recently.

2

Sedimentary cycles in the Callovian-Oxfordian of the Jaisalmer Basin, Rajasthan, western India

Pandey E., Sha J., Choudhary S.

Volumina Jurassica

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2010

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Vol. 8, no. 1

131-162

EN

The Callovian and Oxfordian marine sediments of the Jaisalmer Basin constitute the uppermost part of the Jaisalmer Formation, which comprises the Kuldhar and Jajiya members. In the present paper the authors illustrate retrogradational-progradational, more or less symmetrical cycles representing low- to high-energy marine environments. Despite an incomplete sedimentary record in a profile disrupted by a number of omission surfaces, it is possible to distinguish seven such sedimentary cycles in less than 24 m of sedimentary succession. The cycles, often bearing in their upper parts a thick-bedded well-cemented calcareous sandstone/pack- to rudstone, or hummocky cross-stratified beds indicative of storm events, are occasionally topped by hardgrounds. Hardgrounds provide well-defined boundaries useful for delineating correlative/bounding surfaces, identified here with sequence boundaries (3rd order cycles). Maximum flooding surfaces characterized by richly fossiliferous marly wackestones provide additional correlative horizons. Within these sequences, subordinate cycles can be tentatively distinguished, some of them may represent parasequences. The stratigraphical significance of correlative surfaces and sequences is tested by their fossil content, and these surfaces can be used for regional correlations with neighbouring basin.

3

Distributed loads in an elastic solid with generalized thermodiffusion

Choudhary S., Deswal S.

Archives of Mechanics

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2008

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Vol. 60, nr 2

139-160

EN

The linear theory of generalized thermoelastic diffusion with one relaxation time is employed to study the interactions in a homogeneous, isotropic elastic solid, when a distributed instantaneous source is acting on the free surface of the body. The eigenvalue approach is adopted for the solution of a two-dimensional problem. The Laplace-Fourier transform technique is used. The expansions of the stresses, displacement components, temperature, concentration and chemical potential are obtained analytically. Numerical results are given and illustrated graphically, employing numerical methods for the inversion for transforms. Comparisons are made with the results predicted by the theory of generalized thermoelasticity and elasticity.

4

Deformation due to time harwortic source in orthotropic micropolar viscoelastic medium

Kumar R., Choudhary S.

International Journal of Applied Mechanics and Engineering

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2005

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Vol. 10, no 4

617-629

EN

The present study is concerned with the plane strain problem in a homogeneous orthotropic micropolar viscoelastic solid. The disturbance due to a time harmonic uniformly distributed source is investigated by employing the eigen-value approach. The integral transforms have been inverted by using a numerical technique to obtain the component of displacement, force stress and couple stress in the physical domain. The results of these quantities are given and illustrated graphically.

5

Influence and Green's functions for orthotropic micropolar continua

Kumar R., Choudhary S.

Archives of Mechanics

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2002

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Vol. 54, nr 3

185-198

EN

The article reports on a methodology to synthesize the response of orthotropic micropolar half-space subjected to concentrated and distributed loads. The disturbance due to normal and tangential loads are investigated by employing the eigenvalue approach. The integral transforms have been inverted by using a numerical technique to obtain the normal displacement, normal force stress and tangential couple stress in the physical domain. The results concerning these quantities are given and illustrated graphically.