When mountains move

Monday, 3 May, 2004
Leonie Joubert
Winemakers are dependent on the aqueous arteries that carve their way through the land
If you ever find yourself wandering towards the summit of Mount Everest, you’d better hope that no miniscule air pockets were trapped in any of your fillings. At 8,85 km above sea level the imbalance in pressure between those and the air outside your tooth will shatter the filling.

At that altitude your body will be scavenging what little oxygen it can find and it certainly won’t be enough to fight off any infection that may begin in your tooth.

If you’re lucky enough to avoid this and any of the ill effects of life at such heights – nausea, splitting headaches, lethargy – you may want to scout around the landscape for any sign of marine life. The Himalayas were once the floor of a prehistoric ocean and tens of millions of years later still have the detritus of its past life stored in its many chilly folds.

Everest was pushed heavenward when tectonic plates crashed together about 30 to 50 million years ago, creating the planet’s highest peak (it’s believed to be rising by 4mm per year).

Closer to sea level is another landmark. About 20 million years ago, a finger of land protruding from the lower end of the North American continent reached out like the toe of a chunky ballerina to tip the crown of South America. The two continents which had been separated by leagues of ocean for millions of years suddenly came together, joined by that strange little appendage which today is known as the Isthmus of Panama.

Both are believed to have disrupted air and ocean circulation enough to contribute to ice ages experienced by the planet subsequent to their formations. The crashing together of continents brought about the magnificent folded and rippled mountains inland the Western Cape’s coast and their impact on the weather is remarkable.

Take the massive slab of rock through which the Huguenot tunnel runs – winter clouds bank up against its peaks, pouring out their rain on the coastal side; drive through the tunnel and only a few rags of cloud have made it over the top.

Rainfall on the coastal side measures in at between 250mm and 800mm per year, bringing with it fynbos and renosterveld vegetation. Over the mountains, the rainfall is limited to between 20mm and 290mm in the Succulent Karoo (running along the west coast and immediate interior) and 100mm to 520mm deep in the Nama Karoo, inland of the Cape Fold Mountains (although this is summer rainfall area so moves in from the east of the country and vineyards aren’t found here). Here the vegetation is dominated by succulent-type plants that can survive these near-desert conditions.

For winemakers on ‘the other side of the mountain’, as regions like Worcester and Robertson are known, they’re entirely dependent on the aqueous arteries that carve their way through the land. Without rivers, we wouldn’t know the taste of De Wetshof Bateleur Chardonnay or Graham Beck bubbly.

Those on ‘this side of the mountain’ can rely a little more on winter rain to quench the thirst of their vineyards – although many are still rely on reservoirs for the lean months.

All this, just because a few shifty continents banged into each other.

Further reading or regional maps: A Guide to the End of the World – Everything You Never Wanted to Know, Professor Bill McGuire, Oxford University Press, 2002. www.plantzafrica.com/vegetation