Why are stromatolites rare

But around a billion years ago, the layered rocks abruptly disappeared from the fossil record. Researchers say the extinction is no less dramatic than that of the dinosaurs, yet no one knew what happened to the stromatolites. At the same time, however, another peculiar rock-like living structure began turning up. Climate change is likely to lead to more frequent tropical storms and more frequent flooding events in the area, 4 threatening the Stromatolites of Hamelin Pool.

Human interference is another threat. To protect the delicate structures, visitors are restricted to the boardwalk. From here they may be underwhelmed: Stromatolites look a little like cow pats from that vista.

But, as Stromatolite expert Dr. Erica Suosaari says:. On the border of Hamelin Pool lies Hamelin Station , a , hectare property that we purchased in Hamelin Station was once a pastoral property running sheep and goats. This boundary is obvious in the Grand Canyon area. The churning sediment-laden Flood waters planed off the rocks below as they ground across the continent, laying new sediments on top of a flat surface, known as an erosion surface. So all this evidence indicates an entire environment was buried before the Flood.

How could this happen? But how did these mounds form in the first place? It turns out that these mounds, called stromatolites, were built by algae. We know this because we can observe their living counterparts building small mounds in a few rare places today.

The culprits are blue-green algae cyanobacteria. In warm, salty coastal waters, slimy mats grow on the seafloor sediments.

As they grow, the tides wash in more sediment grains onto the mats, partly burying them. The algae then secrete chemicals that bind these sediment grains together.

So, while the algae are multiplying new cells on the surface, some cells get buried with the sediment grains below. They are effectively fossilized as the mat grows. As this process continues, the mounds build.

They come in a variety of shapes and sizes, from mushroom- shaped domes to columns. At the same time, ocean sediments accumulate around them, entombing the stromatolites.

Not surprisingly to creationists , many living stromatolites are virtually identical to fossilized stromatolites. Every now and then, the local kangaroos popped their heads up to check us out.

And then I saw them. There were thousands of pumice-hued stromatolites quasi-camouflaged beneath the ripples, submerged like migrations of ancient turtles holding their breaths under the slightly opaque water. I was awestruck. Blocking out the peripheral surrounds and imagining the sky methane orange from volcanic activity, this is what life looked like at the beginning of time.

Lake Thetis is just more than 2m deep and double the salinity of the sea. The lake became isolated about 4, years ago when the sea level fell during the last major glacial epoch. Shorelines receded and coastal dunes trapped the water inland, creating the lake.

These stony oxygen givers are estimated to have been growing for about 3, years. A metal walkway braces out over the lake so you can see the stromatolites beneath. On the 1.

Evolutionary progress around a billion years ago started a slow segue that saw the layered stromatolites disappear as another variation emerged. They were their younger cousins: the thrombolites. Thrombolites are clotted in appearance, whereas stromatolites are layered. According to the late Dr Linda Moore from the University of Western Australia, stromatolites went into decline at a time where there was an explosion of more advanced marine life. Their ecosystem became challenged as the predator amoeba and other single-celled organisims called foraminifera used their finger-like extensions to engulf stromatolites, turning their fine, layered structures into clumps.