Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

T. V. V. G. R. K. Murty ¹, L. R. Bhargava ¹

Affiliations
1 Centre of Advanced Research in Geology, University of Saugar, Saugar, IN

Abstract

The basal Delhi conglomerates seen at Bar are reputed for the intense deformation seen in them. Heron's memoir on central Rajputana contains a brief description of these conglomerates.

The pebbles in the conglomerate are mostly made up of quartzites. They vary in size from small pebbles to large cobbles. The percentage deformation in the long axes of the pebbles is around 175, and in some extreme cases about 700. The pebbles lie in the cleavage/bedding surface with their long axes almost parallel to each other. The long axes are coincident with the true dip of cleavage surface.

The overall matrix of the conglomerate is psammo-pelitic and consists of sharply alternating psammite and pelite layers. A strong cleavage is seen in the matrix which is parallel to the bedding.

The pebbles are in all cases flattened and elongated. A two stage deformation model in which an early phase of flattening followed by flow is suggested for the pebbles in the conglomerate.

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T. V. V. G. R. K. Murty ¹, Sharad K. Mishra ¹

Affiliations
1 Department of Applied Geology, University of Saugar, Sagar 470003 (M. P.), IN

Abstract

Geological, geomorphological, geophysical, petrological and mineralisation evidences have been presented to show that the Narmada-Son line is a line of dislocation from Precambrian to Recent times. Maps have been drawn on the basis of available evidence showing the location of the faults. It has also been shown that the Narmada fault system is interconnected with the Tapti and Purna fault systems. The main faults in the system are east northeast-west southwest traversed by a large number of generally north-south trending cross faults. At places the continuity of the ENE-WSW trending main faults is obscure.

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T. V. V. G. R. K. Murty ¹

Affiliations
1 N 2/2, Kakatiya Nagar, Habshiguda, Hyderabad-500 007, IN

Abstract

No Abstract.

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R. P. S. Pahuja ¹, T. V. V. G. R. K. Murty ²

Affiliations
1 Geological Survey of India, Jaipur, IN
2 Department of Applied Geology, University of Saugar, Sagar, IN

Abstract

Pegmatite veins of variable thickness occur in biotite schists and calc schists belonging to Delhi System between Bhim and Todgarh. Rectangular, barrel shaped, lozenge shaped, rotated and folded boudins have been observed in the pegmatite veins. The degree of competency contrast, the degree of strain and the direction of stresses seem to be the controlling factors in the development of boudinage. The thickness of the rock unit behaving homogeneously as a competent band in relation to degree of strain seems significant. Rotated and folded boudins have been attributed to later deformation. The development of boudinage has been shown to be a late feature of the deformation that resulted in F₂ folds of this area.

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