• J K Agrawal

      Articles written in Proceedings – Section A

    • Spectrophotometric study of the uranyl-streptomycin complex

      J K Agrawal R Vijayavargiya S G Harmalkar

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      Spectrophotometric studies of the yellow coloured complex of uranyl ion with streptomycin have been carried out. The complex absorbs maximum at 420 mµ and at a pH value of 3·5. The composition of the complex has been ascertained employing Job’s method, mole ratio method and slope ratio method and found to be 1:1. The apparent stability constant (logK) and free energy of formation (ΔF) of the complex at 40° C have been found to be 3·37 and −4·83K cal per mole respectively.

    • Chronology of Mesozoic volcanics of India

      J K Agrawal Rama

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      K-Ar ages of a number of samples from Rajmahal and Deccan Traps and from basaltic dykes of Gondwanas have been measured. The results suggest that the Early Rajmahals erupted in the middle of early Cretaceous (∼ 110 my) and probably continued to be active till the end of Cretaceous. Deccan activity started in Gujarat-Kathiawar area in Early Paleocene and spread over almost the entire area in next 5–7 my. However, in the north-eastern region of the traps around Chindwara and Amarkantak, the basalts were laid in the middle of the Eocene (∼ 47 my). The measured ages of Deccan dykes suggest a subdued hypabyssal activity continuing till the end of Eocene or beyond.

      The K-Ar ages of Gondwana extrusions exhibit contemporaneity with Deccan activity even for the dykes which are located right close to the Rajmahal outcrops; indicating no regular drift of the foci of volcanic activity. A distant dyke from Cuttack gives an early Rajmahal age, and therefore probably indicates the vast extent to which Rajmahal activity manifested itself.

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