Eocene Depositional Sequence and Cycles in Kutch

Abstract

Two depositional sequences are recognized in the Eocene succession of Kutch. The Sequence-I in the lower part is of Ypressian age and 6 Myr duration. A hiatus of about 7 Myr is estimated between the Deccan trap and Sequence-I and a hiatus of equal magnitude exists between sequences I and II. The Sequence-II is of Bartonian (and possibly extending to late Lutetian) age and a major part of it formed during a small interval of planktic foraminiferal zone E12 (0.5 Myr). A hiatus of ~7 Myr is estimated between the two sequences. Five depositional cycles of low amplitude, low frequency and confined to inner shelf are inferred in Sequence-I. In contrast, eight depositional cycles are recognized in Sequence-II and cycles in the lower part are of high amplitude, reaching to middle shelf. The average cyclicity is of > 1 Myr duration in Sequence-I and < 0.1 Myr duration in Sequence-II.