Welcome to Blackhall Beach! At low tide, you’ll spot an extraordinary structure called a stromatolite. It’s a domed sedimentary structure, about 5 to 6 meters wide and half a meter to a meter high, resembling a doughnut. This stromatolite is a sign of a quiet, intertidal reef environment, formed during the Permian period when a shallow tropical sea, the Zechstein Sea existed.
Stromatolites are created by microbial activity in warm, shallow, intertidal areas. Microbial mats, produced by bacteria like cyanobacteria trap mineral material over time, forming these dome-shaped structures. They form some of the oldest biological structures on the planet.
During the Permian, relative sea-level changed along the coast. When sea levels rose parts of the reef that fringed the coast where submerged, and limestone was deposited in deeper waters. In contrast, when sea levels fell, the reef emerged above water, leading to the deposition of boulder conglomerates due to increased wave energy. Behind the reef, lagoonal environments provided quiet, shallow conditions ideal for the formation of stromatolites.
These stromatolites are significant structures, possibly up to 6 to 8 meters wide and nearly a meter high and associated with the intertidal zone of the ancient reef.
360 Degree Interactive Panorama
The 360 degree view above is located at the centre of the stromatolite featured in the video. The tide has covered it with sand.
