Vineyards & Winemaking
SWARTLAND GEOLOGY
Although viticulture in the Western Cape is relatively young, the geology is quite old. Our vines are planted on the most ancient viticultural soils on earth, and we need to go back half a billion years to see how the landscape evolved.
What dominates the landscape today is a group of Malmesbury Shales (sedimentary rocks) that were deposited 560 to 540 million years ago in an ancient marine basin lying off the African coast. This deposit was folded and uplifted due to the tectonic collision of the African, South American and Antarctic continents around 540 million years ago (Fig. 1).
Intrusions of Cape Granite (igneous rocks) into the Malmesbury shales occurred at the time of this continental collision. Magma, from deep within the earth, rose along the continental fault line into the thick shale deposit, and slowly cooled and crystalised into the granite rocks and hills we see exposed today. Interestingly, granite hills extend in an almost straight line from Cape Agulhas northwest to Cape Columbine (near to Saldanha Bay) - a remnant of this ancient fault line.
The continents then separated, causing the surface to subside and become covered from the north by very deep deposits of Sandstone, called the Cape Supergroup, from 510 to 340 million years ago (Fig. 2).
South America (and the rest of the world) drifted back for more tectonic action from 280 to 235 million years ago, when all the continents came together to form the supercontinent Pangaea. Intensive folding and massive uplifting occurred at this time when South America collided with the southern part of Africa (Fig. 3). Pangaea later broke up, and as the continents drifted away, erosion took over (and continues today) to create the distinctive folded sandstone mountain ranges and valleys of the Cape. Erosion has removed large areas of the Cape Supergroup deposits, which used to be massive mountain range, several kilometres high.
What is left today are sandstone remnants like Kasteelberg and Piketberg (1000-1300 m altitude), resting on granitic and shale foothills and associated with exposed granite outcrops such as the Paardeberg (500-700 m altitude) and ranges of shale based hills like Porseleinberg and the Malmesbury hills (200-400 m altitude), surrounded by undulating Malmesbury shale landscapes.
As human beings, we are given such a short time on this planet to work with the land. It is humbling and exciting to keep this ancient history in mind, and as our vineyards grow in soils derived from all this tectonic activity, it is fascinating to think of the links between how the earth evolved and how wines grown in different sites taste. These humbling thoughts are the fundamental reason for our natural winegrowing and winemaking approach as we strive to bottle wines that reflect the Swartland.
