|
Maybe it's a sign of getting older but I'm discovering that previously shunned topics are becoming more and more interesting...
Topics like geology - A fashionable discipline in the sternly scientific 19th century, it made way for the much sexier physics in the 20th century and hasn't really recaptured the public's imagination since, let alone mine.
It is, however, the foundation – literally – of all that we see, stand and live on, and deserves a little more recognition than a casual dismissal as a bunch of rocks.
And in the Cape not only are we are slap-bang in the middle of some serious rocks but we can view so much of it so easily. Besides, once we understand what we're sitting on, we can better understand our environment.
The story begins back in the late Precambrian period, a time so long ago that rocks were only just being formed in a tumultuous, molten world.
The Malmesbury Group, a collection of slates and sandstones, was laid down some 650 to 540 million years ago and has suffered such geological trauma that the strata are now nearly all vertical.
Into this bed of rock was injected molten Cape Granite, peppered with glittering mica and quartz and it was all overlaid some 280 million years ago with the red, purple and grey hues of the Table Mountain Sandstone Group.
That said, what does it all mean? Well, if you're anywhere in Cape Town you really can't miss the evidence of all this. The weathered sandstone buttresses of Table Mountain rise in grey layers from its ancient basement rocks.
Stubborn lumps of more resistant granite stand out – Lion's Head is the most obvious. Globs of once liquid granite that were forced into Malmesbury sandstones have frozen into a child's play dough mix of rock along Sea Point Promenade (even attracting Charles Darwin's interest on a visit here in 1844).
The ancient rocks have been heavily eroded – you can see it as you drive south down the peninsula next to the chain of granite-tipped mountains lurching up and down the peninsula like an erratic sales graph.
The Cape's mountains are craggy, deeply cut with valleys and crumbly. Huge boulders of granite have lumbered down mountain slopes and stand pleasingly poised above ostentatious mansions at Llandudno or forlornly marooned on the beach at Boulders.
The famous scenic drive of Chapman's Peak is worth a quick look from a distance: the road sits neatly between the layers of granite and sandstone.
But the rocks are only the beginning: take a walk on the mountains – anywhere will give you a chance to see, touch and sit on great lumps of ancient rock – and then have a look at the vegetation that the geology supports. It's fynbos, that magical mixture of unique plants that thrives on poor, leached acidic soils.
Head up the west coast where sand dominates and watch the vegetation abruptly change into sandveld specialists – fleshy leaved plants sprawling low over dunes.
Turn east and drive through the agricultural Swartland on your way to the Overberg region on the other side of Cape Town's encompassing ring of mountains.
The fertile clay soils of these areas support a patchwork of neat fields and a thriving wheat industry; the remaining indigenous renosterveld only survives in mountainous strongholds.
But for the real stuff, drive along the R400 via Worcester and head for Montagu. Here you can see geology on steroids, the colossal forces of plate tectonics in action.
Millions of tons of rock have been thrown up into mind-boggling twists and turns - stretched, teased and moulded into layers that a hairdresser would be proud of.
The tortured strata will make your jaw drop and pull the car off to the side of the road; as you gape at the masterpiece perhaps the same kernel of interest will twitch in your mind as happened in mine, and geology, that dusty old study of lifeless stones, starts to rock.
|
