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

Fareedduddin ¹, A. K. Sharma ¹, U. Bose ¹

Affiliations
1 Geological Survey of India, Jhalana Dungari, Jaipur-302 004, IN

Abstract

The occurrence of tectonic slices of high-grade rocks in Pilwa-Chinwali-Arath area, about 25 km NNW of Ajmer is described. They occur in discontinuous strips Over a distance of 25 km within the Alwar metasediments of middle amphibolite facies. The high-grade sequence comprises charnockite-enderbite, two pyroxene granulite, pelitic granulite, leptynite, garnetiferous augen gneiss and garnetiferous amphibolite. Their tectonically-controlled occurrence and comparable mineral parageneses, the highgrade granulite facies rocks of the study area show striking similarity to those of Sandmata metamorphites emplaced in the Archaean Banded Gneissic Complex.

Keywords

Tectonic Slices, High-Grade Rocks, Granulite Facies, North-Central, Rajasthan, Delhi Fold Belt.

Full Text

     

Utpal Bose ¹, A. K. Sharma ¹

Affiliations
1 Regional Geology Division II, Operation: Rajasthan, Geological Survey of India, Jhalana Dungri, Jaipur 302004, IN

Abstract

An arcuate belt of Precambrian vo1cano-sedimentaries, designated as the Hindoli Group, is sandwiched between the cratonic Archaean Banded Gneissic Complex terrain and the platformal Vindhyan sediments. Turbidites of mainly quartz wacke and petites with interlayered lava flows and tuffs of basalt, basaltic andesite and daciterhyodacite composition constitute the bulk of the Hindoli vo1cano~sedimentaries. These are interpreted to have been deposited in a continent-marginal basin with active participation of an arc system. Toward the end of the basin evolutioo; the continent-margin acted passively when quartzarenite and carbonates were deposited in a stable shelf regime.

Keywords

Hindoli Group, Precambrian, Turbidites, Continent-Marginal Basin, Rajasthan.

Full Text

     

Utpal Bose ¹, A. K. Sharma ², A. Om Kumar ³, S. K. Minda ⁴, S. Banerjee ⁴

Affiliations
1 OSI, NH-5P, Faridabad-121001, IN
2 GSI, Jhalana Dungri, Jaipur-302004, IN
3 GSI, Bandlaguda, Hyderabad-500660, IN
4 Govt. of Rajasthan, Udaipur, IN

Abstract

Felsic volcanics of rhyodacitic composition have recently been recorded in the Late Archaean Berach granite massif underlying the eastern flank of the Hindoli volcano sedimentaries in southeastern Rajasthan. Feldspar-phyric lava flows and lapilli-bearing pyroclastics are the two main volcanic components.

Keywords

Felsic Volcanics, Berach Granite, Hindoli Group, Rajasthan.

Full Text

   

N. H. Hashimi ¹, M. C. Pathak ¹, P. Jauhari ¹, R. R. Nair ¹, A. K. Sharma ², S. S. Bhakuni ², M. K. S. Bisht ², K. S. Valdiya ²

Affiliations
1 National Institute of Oceanography, Goa - 403 004, IN
2 Department of Geology, Kumaun University, Nainital - 263 002, IN

Abstract

The Naini lake is a product of rotational movernent on a NW-SE trending Nainital Fault, quite after the establishment of the drainage of a mature stream named Balia Nala. Detailed bathymetric study, permits division of this crescent-shaped lake into two subbasins separated by an approximately 100 m wide transverse underwater ridge, 7m to 20m below the lake surface. The southeastern and northwestern parts, 11 to 25 m and 4 to 27 m deep, respectively, are filled with unconsolidated sediments, 15 m thick on an average. The semiconsolidated sedimentary layers locally exhibit slumping an slopes and deformation in channel beds. These features together with thetransverse Central Ridge, the deep channel cutting through it, the small scarps and terraces or step-like features on the slopes of the narrow V-shaped undemater valley in the southeastern part and its thick filling in parts due to blockade resulting presumably from fault movements, and the existence of deformed and displaced acoustic reflectors are interpreted as indicating quite recent movements along the Nainital Fault. Hitherto unidentified pinnacle-like objects penetrating through or perched atop sediments, are suggestive of either tectonic displacement and squeezing or of the hazard of mass movements which have occurred. A number of small but rapidly growing deltas along shores indicate accelerated pace of sediment input, resulting from quickened erosion in the catchment area.

Keywords

Naini Lake, Neotectonism, Bathymetric Study, Kumaun Himalaya.

Full Text

     

A. K. Sharma ¹, S. T. Seshadrinath ¹, R. P. Sinha ¹, P. V. S. Naidu ¹

Affiliations
1 Atomic Minerals Directorate (AMD), for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, IN

Abstract

No Abstract.

Full Text