Table mountain's ancient story unfolds through deep time

Earth scientist Professor John Compton describes Table Mountain not as a static landmark but as an ongoing geological narrative spanning millions of years. Formed from ancient sands and shaped by continental shifts, the mountain offers a perspective on enduring natural processes amid modern anxieties. Compton emphasizes how understanding this deep time can provide comfort and humility.

Professor John Compton, an earth scientist, views Table Mountain above Cape Town as more than a landmark; it represents a vast story of geological and biological evolution that continues today. The visible quartzitic sandstone cliffs originated as loose sand grains eroded from the Cargonian Highlands, an ancient range formed over 600 million years ago during the collision of continents into the supercontinent Gondwana.

These grains were transported by braided rivers across a barren landscape between 545 and 444 million years ago, accumulating in the Cape Basin without precise dating due to the absence of fossils or datable minerals. Over time, additional sediments buried these deposits up to seven to nine kilometers deep, compressing them into durable rock where quartz cement filled the pores, making it more resistant to erosion than the underlying granite.

Around 250 million years ago, tectonic collisions deformed the Cape Supergroup into the Cape Fold Belt, positioning Table Mountain low in a fold. As Gondwana later rifted apart, uplift exposed the formation, with its current shape emerging in the last 40 to 50 million years through erosion by rain and rivers. This makes Table Mountain the westernmost remnant of the ancient fold belt, a sandstone remnant standing after surrounding softer rocks eroded away.

Compton highlights the philosophical value of deep time, noting it places current concerns like climate change and political instability in a broader context. 'I don’t take the daily news quite as dramatically as many people,' he says, explaining that the mountain has endured ice ages, extinctions, and supercontinent breakups. Geologists observe ongoing processes, such as the cliff retreating at 5 meters per million years via rockfalls and faults.

Ultimately, Compton urges people to observe the mountain closely to foster curiosity and patience, recalibrating their sense of time against its 500-million-year history of uplift, erosion, and persistence.

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