Analysis of Ichnoguilds and their Significance in Interpreting Ichnological Events: A Study from Jhuran formation (Upper Jurassic), Western Kachchh

The ichnological study of the Jhuran Formation (Kimmerdgian-Tithonian) exposed at Jara Dome of Western Kachchh has revealed the presence of twenty-two ichnospecies. These ichnofossils are typically well expressed at bed transitions, especially at intercalated shale-siltstone-sandstone sequences. The Jhuran Formation is divided into seven lithounits represented by six ichnoguilds exhibiting four distinguishable ichnological events. These events can provide important information on palaeoenvironment, depositional cyclicity and behaviour of the trace making communities. This is illustrated by the quantitative analysis of ichnoguilds in the intercalated sequence. The recurring patterns of the ichnoguilds reveal activity levels within the substrate, feeding style and also reflect colonization events at different beds. The dominance of structures produced by specialized organisms is consistent with an open marine unconsolidated substrate setting. The typical features of each ichnoguild allow characterization and comparison of local palaeoenvironmental conditions (depth, hydrodynamic condition, etc) which mark different ichnological events in the upper Jurassic sequence of the Western Mainland Kachchh basin.