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GENEALOGY REVISITED

Updated: May 25

If you have ever traced your family line you’ll know that if you get back to 1700 you’re doing well. The Barberton Greenstone Belt has plentiful sandstones that contain early life forms quite a bit older — about 3.2 billion years older.

Main picture on the panel above: How Earth’s Archaean coast might have looked looking north from the biomat boulder/Dycedale Syncline.

Transporting the 22 tonne boulder with its embedded biomats to its new location.


Along the trail, at the Dycedale Syncline, there’s a sandstone boulder on which you can see wavy grey-green lines, the fossilized remains of microbial mats that once covered extensive sand flats on the shores of a shallow ocean — and like it or not, these are likely your distant ancestors. This is not something everyone can accept but you can take comfort from the fact that there is an immense gulf between you and these mats, and there have been a lot of fortuitous events that had to happen exactly as they did in order for you to be standing at the boulder.

Even these 3.2 billion-year-old fossils are not the oldest life forms along the trail. At the Black Chert/Volcanic Lapilli site are large black boulders of chert. Chert you probably know was used by Man for millions of years to make tools and weapons — very sharp tools and weapons. Even today, chert is used to make the edge on some of the finest surgical instruments.



The pale lines in the black chert are formed of volcanic ash and so they record sequences of eruptions. The black of the chert is the result of carbonaceous material (kerogen) in which microfossils have been found.


Chert is actually a fine precipitate of silicone dioxide — a microcrystalline quartz that settled on the ocean floor some 3.4 – 3.5 billion years ago. It is in this fine-grained black rock, also found in Western Australia, that some geologists believe they have found the remains of microorganisms without a nucleus, but perhaps the very first life on Earth.




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