Nishith Y. Bhatt¹ and Satish J. Patel²

¹Department of Geology, M.G. Science Institute, Ahmedabad – 380 009.

²Department of Geology, M.S. University of Baroda, Vadodara – 390 002.

Email: nybhattmg@yahoo.com; sjpgeology@gmail.com

Abstract

Bhuj Formation, well exposed in the Khatrod (Katrol) hill range, southeast of Bhuj, comprises ~395 m thick clastic sequence ranging in age from Berriasian to Albian. The lower part of the sequence is shaly which gradually show intercalation with sandstone and finally become arenaceous at the top. Studied sequence is divided into eight sedimentary facies which are highly bioturbated and consist of well-preserved identifiable trace fossils, which are grouped into eight ichnoassemblages namely, Asteriacites, Chondrites, Diplocraterion, Gyrochorte,Ophiomorpha, Rhizocorallium, Skolithos and Thalassinoides. The presence of Gyrochorte, Rhizocorallium and Thalassinoides ichnoassemblages marked the change in bathymetry and fluctuating energy conditions in wave dominated delta region. Sedimentary facies displayed the coarsening upward sequence; the lower part comprises mainly shales with minor siltstone and fine sandstone while upper part is dominated by thick cross-bedded sandstones. The sedimentological and ichnological data of the Cretaceous of Bhuj Formation depicts the minor fluctuations in sea level that gave rise to three transgressive-regressive cycles in wave dominated deltaic environment.

Keywords: Sequence Stratigraphy, Bhuj Formation, Mesozoic rocks, Khatrod Hill Range, Mainland Kachchh, Gujarat.