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Authors
Affiliations
1 Geochronology and Isotope Geology Division, Geological Survey of India, 15 A & B, Kyd Street, Kolkata - 700 016, IN
2 Geological Survey of India, Operation Gujarat, Gandhinagar - 382 093, IN
3 Central Petrological Laboratories,
Geological Survey of India, 15 A & B, Kyd Street, Kolkata - 700 016, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 66, No 5 (2005), Pagination: 599-608
Abstract
Field evidences in Kachchh show that alkali basalts occur as flows over Mesozoic sediments. The top parts of Mesozoic Bhuj Sandstone often carry scoria and lapilli related to alkali basalt magmatism indicating that alkali magmatism and sedimentation went side by side. Tholente flows occur as blanket over both Mesozoic sediments and alkali basalt bodies.
Evidences are provided to show that alkali basalt magmatism in Kachchh was not only an earlier episode than tholente emplacement, it also predates the closing of Kachchh Mesozoic basin and seems to support a protracted period of Deccan magmatism (70 - 60 Ma). The study also shows that huge concentration of alkali basalt in the western Kachchh mainland is associated to a zone of transtension related to the rifting of Kachchh basin. Alkali basalt bodies and whole of Mesozoic sequence were affected by reverse faults related to closure of Kachchh basin with development of series of hanging wall anticlinal and footwall synclinal structures.
Keywords
Alkali Basalt, Tholente, Flow, Plug, Releasing Bend, Kachchh.
