TRACE FOSSILS FROM THE KALADONGAR FORMATION EXPOSED IN KUAR BET, PATCHAM ISLAND, KACHCHH BASIN, INDIA

摘要

The Kachchh palaeorift basin is famous for its Jurassic exposures the world over. The basin, initiated in Early Jurassic, comprises well exposed sediments from Bajocian onwards. The Kuar Bet is a small island on the northern part of Patcham Island, Kachchh, having exposures of the basal part of the Kaladongar Formation. Lithostratigraphically, these are considered to be the oldest exposed beds in the Kachchh palaeorift basin. Eight recurring ichnospecies are reported here. These include Arenicolites of statheri; Cochlichnus isp; Diplocraterion parallelum; Diplocraterion polyupsilon; Ophiomorpha nodosa; Paleophycus; Rhizocorallium jenense; Skolithos linearis. These ichnotaxa are divided in four Ichnological assemblages (1) Diplocraterion (2) Ophiomorpha (3) Arenicolites-Skolithos and (4) Rhizocorallium-Paleophycus. The trace fossil occurrences and their recurrence pattern indicate marginal marine conditions followed by shallow marine conditions for the sediments of Kuar Bet.