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

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Stylolitic Origin of Chrysotile Asbestos Near Pulivendla, Cuddapah District, Andhra Pradesh


Affiliations
1 33/4 RT, Barkatpura, Hyderabad-500027, India
2 Dept. of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore - 560012, India
3 A/3, Himanshu Bhawan, Sawai Jai Singh Highway, Jaipur-302006, India
     

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The field observation that chrysotile asbestos near Pulivendla is localised along stylolites in the Proterozoic carbonate sediments of the Vempalli Formation (Cuddapah Supergroup) proved crucial and paved the way for a re-thinking on the origin of Pulivendla asbestos. The length of the fibre, nowhere, transgresses the amplitude of the stylolite. Further, the lateral termination of the chrysotile seams invariably coincides with that of the enclosing stylolite. The stylolite development and fibre growth appear to be a sequel to directional pressure. X-ray and infra-red studies of the massive serpentinous zones revealed dioctahedral dewelyite to be the main serpentine mineral. It is suggested that the chemical pre-requisites (e.g. magnesia, silica and hydroxyl molecules) necessary for serpentinisation and pari passu chrysotilisation, were present in the carbonate sediment itself at the loci of stylolitisation and that the intrusive dolerite merely provided the desired thermal energy. The emplacement took place, possibly, when the carbonate sediment was in a semi-consolidated stage. Stylolitisation and chrysotilisation appear to have ceased with the complete consolidation of the enclosing sediment.
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  • Stylolitic Origin of Chrysotile Asbestos Near Pulivendla, Cuddapah District, Andhra Pradesh

Abstract Views: 177  |  PDF Views: 2

Authors

P. K. Ramam
33/4 RT, Barkatpura, Hyderabad-500027, India
G. V. Ananta Iyer
Dept. of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore - 560012, India
T. R. Narayanan Kutty
Dept. of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore - 560012, India
M. V. N. Murthy
A/3, Himanshu Bhawan, Sawai Jai Singh Highway, Jaipur-302006, India

Abstract


The field observation that chrysotile asbestos near Pulivendla is localised along stylolites in the Proterozoic carbonate sediments of the Vempalli Formation (Cuddapah Supergroup) proved crucial and paved the way for a re-thinking on the origin of Pulivendla asbestos. The length of the fibre, nowhere, transgresses the amplitude of the stylolite. Further, the lateral termination of the chrysotile seams invariably coincides with that of the enclosing stylolite. The stylolite development and fibre growth appear to be a sequel to directional pressure. X-ray and infra-red studies of the massive serpentinous zones revealed dioctahedral dewelyite to be the main serpentine mineral. It is suggested that the chemical pre-requisites (e.g. magnesia, silica and hydroxyl molecules) necessary for serpentinisation and pari passu chrysotilisation, were present in the carbonate sediment itself at the loci of stylolitisation and that the intrusive dolerite merely provided the desired thermal energy. The emplacement took place, possibly, when the carbonate sediment was in a semi-consolidated stage. Stylolitisation and chrysotilisation appear to have ceased with the complete consolidation of the enclosing sediment.