Rockforms 11: Beach Pebbles

Image Commentary

We choose to show this in juxtaposition to Mushroom Rock because these beach pebbles illustrate a dramatically contrasting erosional process to that of Mushroom Rock. At "the Rock" the main source of erosive energy was the wind. whereas here it is water and the tumbling action imparted to the pebbles by the movement of the shoreface waves. The constant rolling of these pebbles one against another in the ever presence of moving water has caused them to have almost perfectly smooth surfaces regardless of their individual mineral make-up. In fact there is a high degree of variability between each of these pebbles, some are almost entirely quartz, others are volanic or intrusive igneous rocks made up of high amounts of quatrz and other silicious minerals. Despite this though they do have a similar degree of hardness.