Picture of the month
February 2012
Striated, Rounded, Polished, Snapped off, Rotated, Transported & Dumped by a glacier
Comment:
This sizeable limestone erratic has dropped out of an eroded drumlin and now sits on the shoreline of Morecambe Bay at Aldingham adjacent to the still eroding drumlin which defines the boundary of the bay at this point. It is almost certain that the erratic was originally part of the exposed bedrock on what is now known as Birkrigg Common 3.3 km to the north and approximately 130 m higher than the shoreline. The striation marks and rounding bear witness to the wearing action of the abrasive ice and embedded rock debris as it passed by the rock when still part of the bedrock mass. The rougher surfaces have escaped the abrasion by originally being down-flow to the ice movement. Given that this is no longer the case as the erratic sits on the beach, it indicates that after it eventually capitulated to the great forces of the ice movement and snapped off the bedrock, it must have rotated prior to settling in its present position,