Informatics Publishing Limited

T. N. Parthasarathy ¹, P. Rajasekharan ¹, Y. S. Manjunath ¹, S. N. Chaturvedi ¹, A. Bose ¹

Affiliations
1 Atomic Minerals Division, Hyderabad-500 016, IN

Abstract

Ultramafic-mafic rocks of komatiitic affinity are reported from the Kerali area of Abujhmar basin in Bastar Craton, Madhya Pradesh. These rocks, occurring below the Gundul sandstone member of the Middle Proterozoic Abujhmar group, are composed of peridotitic komatiites, pyroxenitic komatiites and basaltic komatiites, besides tholeiites and microgabbro emplaced into them as dykes. Petrographically, olivine and pyroxene occur both as major phenocrysts, and as microphenocrysts, with the groundmass made up of interstitial glass. Normatively, these rocks are both olivine and hypersthene normative. Petrochemical data plots on discriminant ternary diagrams such as AFM, Jensen Cation plot, MgO-CaO-AI₂O₃ diagram, indicate their close similarity to the komatiitic trends shown by the type area rocks from the Munro Township area, Canada and Yilgarn Block of West Australia very much paralleling the trend of Barbertonland komatiites. Trace element data involving Ti, Y, Zr and V plots also points out that these rocks fall in the kornatiitic field as against the tholeiitic field. Tectonic environment discriminant diagram involving the plots of these ultramafic-mafic rocks indicates the possibility of deep passive or 'failed' (?) rift in the region through which these ultramatic-mafic rocks of komatiitic affinity might have been emplaced.

Keywords

Ultramafic Rocks, Komatiite, Petrochemistry, Abujhmar Basin, Bastar Craton, Madhya Pradesh.

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A. Bose ¹

Affiliations
1 Indian Cryogenics Council, Jadavpur University Campus, Calcutta-700 032, IN

Abstract

Friction, an irreversible phenomenon of Nature, is most often a necessity, but quite often a nuisance. Without friction there could be no locomotion of bodies en masse and all solid structures would fall to pieces. On the other hand, friction is one major source of irreversible loss of energy in all types of motion leading ultimately to increase the entropy of the physical systems.

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