DEVELOPMENT OF PARASEQUENCES AND PARASEQUENCE SETS WITHIN A DEPOSITIONAL SEQUENCE DURING THE MIDDLE JURASSIC OF KACHCHH BASIN, GUJARAT, WESTERN INDIA

The Kachchh sedimentary basin is a pericratonic embayed basin on the western margin of India, which has developed condensed sections of sediments exposing from Bathonian to Pleistocene. During the Middle and late Jurassic period, almost the entire Kachchh and Rajasthan region of Western India was covered by a gulf, which has evidently in direct connection with Tethys in the north. The paper discusses the sedimentological characters, microfacies distribution, and diagenetic sequences of the middle Jurassic deposits of Kachchh basin, developed with in a transgressive-regressive sea across the basin. The present study focuses on the development of parasequences and parasequence sets developed during the rise and fall of Tethys sea, and the evolution of facies characteristics within the depositional sequence through diagenetic processes during the post-depositional activities. Three types of parasequences are identified from the microfacies studies (Subtidal, Peritidal and Intertidal-Supratidal), which are cyclically stacked into a retrogradational stacking pattern in a transgressive system tract and progrades into a progradational intertidal-supratidal facies during the lowstand system tract. The diagenetic sequence and diagenetic cement types are also well documenting the transgressive–regressive pattern of the Tethys sea across the basin. The sedimentological characters and various carbonate components and their diagenetic signatures reveal the development of parasequences and parasequence sets with in a major transgressive sea during which the Sequence I (Jhurio Formation) has been developed. The present study is the integrated research on the sequence stratigraphy of this Sequence I (Jhurio Formation).