Discovering early Earth on a trip
Bridget Hilton Barber and her road tripster buddy Hugh Fraser set off on a journey to take in unique sights that speak of events which happened billions of years ago. It leads them straight to Barberton in Mpumalanga
IYou could spend the whole day exploring the geotrail. It’s one great big, beautiful geology lesson plus the profundity of the
first life on Earth
n the beginning, long before rolling blackouts, there was darkness. This was the Hadean Eon some 4.6 billion years ago, when the Earth’s mantle and crust and its inner and outer core took shape in a fiery embryo. Then came the Archaean Eon, about four billion years ago, when the continents formed through impossibly outrageous seismic activity.
Think massive meteorite impacts, bigger than the one that killed off the dinosaurs, wild lightning storms and giant balls of molten lava. The young oceans cooled, cracking the Earth’s rocks, and through a complex chemical process transformed carbon-containing molecules into simple living cells – single-cell bacterial structures that would be the fundamental nucleus from which all animal and plant life evolved.
Hello, Archaeospheroides barbertonsis.
There is evidence of these very first singlecell bacteria in the Makhonjwa Mountains World Heritage Site, the mountains that loom above the town of Barberton. There is no other place in the world, says Unesco, where scientists can recover as much information about this important formative period in Earth’s history.
We kicked off our adventure at Bushwhacked Barberton, a charming rustic spot just above the town. It was Hugh’s birthday and, to a suitably dramatic sunset, we opened a huge magnum of bubbles. We met owner Catherine Wilson, who regaled us with tales of visiting geologists, scientists from Nasa, filmmakers, a guest who came
for a night and stayed 18 months.
We made new best friends with the people from the Lonely Planet guide, who were also staying here, and we all noisily talked life and travel at the same time. By the time the bubbles were finished, neither Hugh nor I could pronounce Archaeospheroides barbertonsis.
The next morning we resumed our mission and set out along the Barberton Makhonjwa Geotrail. It’s a 38km-long mountain pass on the R40 between Barberton and the Josefsdal border with Eswatini. There are 11 landscaped picnic spots with viewpoints along the way, each with interpretative panels explaining the rock specimens and geological features.
The idea is to travel slowly, get out and look, and build a picture of how early Earth evolved about 3.6 billion years ago.
We couldn’t resist getting out at most of the viewpoints. The Makhonjwa Mountains, or the Barberton Greenstone Belt, as they’re geologically known, are serious eye candy. We had snacks, coffee and an essential travel guide called the Barberton Makhonjwa Geotrail by Tony Ferrar and Christopher Heubeck (you can also download it).
It is designed to bring the geology here to life, explaining things like the formation of the continents and the environment in which life first appeared on our planet some 3.5 to 3.2 billion years ago.
Different viewpoints showcase different rocks that make up the Barberton Greenstone Belt, and you can go as geo-nerdy as you like, spending hours delving into things like pillow lavas, volcanic lapilli, banded iron formations, and a chert clast conglomerate also known as puddingstone.
Or fascinating komatiite, formed from extremely hot (1,600°C) lava flows on the sea floor that cooled rapidly, forming big, bladed crystals, known as spinifex texture. And try to imagine that ultrathin sections of black cherts – extremely fine-grained silica laid down as a chemical deposit under water – have revealed small spheres, the fossils of