TITLE    INTRODUCTION    DETRITAL ROCKS    CHEMICAL ROCKS    

BIOCHEMICAL ROCKS    ENVIRONMENTAL CLUES    CREDITS

BIOTURBATION

graded bedding    cross bedding    ripples    mud cracks

raindrop impressions    tracks and trails    fossils

Bioturbation, that is, the disturbance of sediment layers by biological activity, is a significant process on the ocean floor.   In that environment, numerous animals such as worms exist by consuming organic matter trapped between sediment grains.   Animals like clams burrow through sediment to hide from predators swimming or crawling above the ocean floor.   Either activity requires the animals to burrow through the sediment, destroying some of the pre-existing sedimentary features such as cross bedding or ripples.  

Burrows within sandstone.        Traces of burrowing animals in limestone.       Disruption of layers within limestone.