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For Once - Put Your Head in the Ground


Looking at horizons, which is why we travel; and, in Cape Town's case, why we settle; we often forget what we're standing on. If you live in or visit Cape Town, you might want to change that. Like it's spectacular landscape above the ground, Cape Town has a geologic history so astonishing that you're missing more than half the story if you don't, for once, put your head in the ground. The fact is that Table Mountain is among the oldest mountains on earth; more than five times older than either the Rockies or Himalayas.

Before we start, for reasons that will become clear as you read, you need to understand that the rocks of Table Mountain; like the rocks of the surrounding escarpment; formed at and below sea level, but because of an an ancient injection of granite under this region - a rigid rocky skeleton that protected the mountain's softer sandstone plateau above from buckling - the mountain was shoved into the sky as one whole, the way a cork pops up and floats when a bath is run... it will all be clear in a moment:

When you look at the mountain's flat-planed skyline, an obvious impression will leap out at you... it looks like a God took a plane to it, giving it the peculiar hallmark level that put the 'table' into its name. If you get this impression... that it was leveled, your instinct would be spot on - it has been carved flat, crushed and scoured under thousands of feet of ice in an epoch long gone.

Unbelievably, the top of Table Mountain was once the the bottom of an ocean, and later, the base of a glacier too. The evidence of this is clear the moment you crest over the kilometer high (3,563 feet) wave-cut cliffs and lip, and start trudging around on beach sand... yes! Beach sand!!

Back at sea level; if you find yourself at the end of Queens Road, Sea Point, do yourself a favour and amble across the parking lot toward the promenade above the sea. Southward, to your left, you will see the light-coloured and weather-rounded crystalline granite boulder formations of Clifton and the rest of the Southern Peninsula - to the north is the black shale of an earlier epoch. This is known as a "contact zone" - a place where the titanic forces of the earth are laid bare and xenolithic intrusions are common. A plaque describing the details of this terestrial struggle is placed helpfully at the spot.

The dark shale that forms the bulk of the mountain's base was deposited (800-million years ago) as a continental shelf under a deep ocean. This was an epoch before the kind of multi-cellular life that leaves visible fossils got its start on earth; so that the rocks of our mountain are devoid of any exciting once-living finds.

But what we do find under its base is a hard shell of 'igneous' rock - rock not deposited as sand and then pressured together to form rock, but molten rock ('ignis'; latin for 'fire') of the volcanic type that, 600-milllion years ago was injected into the existing shale, where it cooled into tough granite. So that the granite of Clifton, Camps Bay, Llandudno and beyond did not roll and tumble down the mountain as it appears to have done, but was rather weathered to its current state in situ.

But, leaping back a half a billion years; if you'd been at the spot of what is now Table Mountain, you'd have encountered a strange thing - not a mountain at all and not a coastline either, but a continuous landmass below an ocean; now fractured, the other half of what we were is gone far over the horizon... Antarctica.

We in our era of learning have come to understand something extraordinary about our earth - tectonics have taken our world and inched the land apart, as whole continents fled away from one another at the speed fingernails grow - and thus the saga continues to this day. Antarctica and South America were once part of our small conference down south here, abutted hard against us - a province of a long-gone continent - Pangea now ripped apart.

* For interest; "pan" means "all", and "gea" means "land". It derives from the Greek 'Gaea' - The goddess of the earth, who bore and married Uranus and became the mother of the Titans. The word 'Gaia' derives from the same root.

The turmoil of tectonic forces deep in the earth had pressed the seabed steadily upward above sea level, draining off the ocean so that erosion and deposition of sands were grinding and baking accumulating layers of sand into sandstone rock.

These sandstone layers are beautifully exposed along the cut-cliffside on Chapman's Peak drive, the road itself planted on the hard granite base.

Then - a little over half the mountain's life ago; around the 300-million year mark; long before the continent began to split up up, you'd have found a terestrial plain at sea level where Table Mountain now stands; its rocky base and layers in place, but capped with snow - a whole lot of snow - thousands of feet of snow; a great moving river of snow, crushed into ice by its own weight, inching along under gravity - a glacier creating a plateau. You'd have seen no ocean back then, this spot on earth was still in the middle of the vast Pangea continent.

Until tectonics was understood, quite how this mountain came to thrust toward the sky where as it does would have been perplexing - but now we do understand. Pangea was being assaulted by tectonic forces from below, the Cape area was buckling and folding - the evidence of this violent period so plainly visible in the surrounding mountains. But where Cape Town now stands, the granite base injected at the 600-million year mark now began to play its part, resisting the sandstone from buckling, and directing the forces deep in the earth to shove the plateau up into the sky.

Fast forward to the age of dinosaurs, a hundred million years before their demise - Pangea was in its death throes, tearing apart - Our southern cluster of land became Gondwanaland, before it too fractured; sending Australia, India, Antarctica and South America on their voyages into the distance, floating on a mantle of heavier rock deep inside the earth. Africa - once the centre of the confederation - was stationary; the other familiar southern continents recoiling in slow motion away from it.

The buckling of surrounding mountains continued - but Table Mountain's integrity rode out the tumult on that granite base, the folding forces deflecting the pressures to push it ever more upward, as erosion sought to tear it's ramparts down into talus. At last, Table Mountain stood in proud relief of the waring forces that raged all around it - buckled mountains to the north feeding the crystal streams with the perfect vineyard-ready runoff of eroded soils - to the south, east and west of the Table Mountain range pinnacle into the sea; a deep crisp ocean stocked with sumptuous fare.

But nothing lasts forever and the forces continue to shape the region - To get a sense of the erosive forces that shape this place:

  • Come stand on Camps Bay beach with us on a day when the South East wind is blowing all trace of human pollution fast over the horizon. Feel the lash and ecstatic sting of sandgrains hurled against your legs; the sting that, for millennia, has chipped away at the granite outcrops in an unending attempt to finally prune the mountain back to a level plain.

  • Witness the ocean in our spectacular winter storms relentlessly battling to regain dominion once more over the beaches it once set atop the buttress; beaches it denudes of sand, exposing the rockbed, deep cleaning the sugar-like grains before returning them, pristine and achingly white, each spring.

  • You have not lived until you've sat at the foot of the folded mountains, sipping from the fruit of the vines before a crackling log fire as the tempest of North West wind howls its mournful song for cousin continents now gone to less pleasant climes - because Cape Town wound up at precisely the same latitude as San Diego, Spain, Italy and Greece - with the perfect climate.

At last, in our era, the gnarled and cragged old wizard that is our mountain has grudgingly given up its secrets to modern explorers who have probed its coast and caves. There are stories around these shores to entertain a person for a lifetime.

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