Wind Generated Tool Marks Resembling Trace Fossils in a Shallow Estuarine Environment

A suite of tool marks were observed in the seaward section of a small estuary on the south coast of New South Wales, Australia. The marks were formed through wind dragging Eucalyptus leaves and Casuarina fronds over the backshore sands that separate the closed estuary from the sea. A number of the more complex marks closely resemble trace fossils left by fish, and differentiation between the two in the sedimentary record could be difficult. If correctly identified as tool marks then they would give a spurious estimate of palaeoflow direction, as they correspond to the orientation of the prevailing winds that generated them. This study highlights the need for judicious interpretation of ambiguous grooves in the sedimentary record.