Upper Barakar Lebensspuren from Hazaribagh, India

A five metre thick silty-sandstone unit, below the topmost coal seam of the Barakar Formation, has been given a status of 'Burrrow Zone' owing to the presence of trace fossils in large numbers and variety. Six geometric forms have been described. The first two represent horizontal intrastratal burrow system (branching and nonbranching), and were produced by fresh water crickets. The fecal pellets (type 3) and the associated vertical tubular burrows (type 6) are correlated with one or both of beetles and crustaceans. Selective search for food from organic matter-rich sediments led to the formation of these fecal pellets. Type 4 and 5 structures represent trail marks of horsehair worms on the sediment-water interface.

Late Barakar basin experienced a very low energy condition of deposition which accelerated the luxuriant growth of plants and organic activities in all possible interfaces. Sudden change over to high energy condition prior to the start of Barren Measure sedimentation ceased all biogenic activities. This resulted in the formation of a burrow zone below the Barren Measure Formation.