The Western Cape's viticultural soils are ancient, shaped by millions of years of geological processes. The landscape displays late Precambrian Malmesbury Group shale and schists deposited in a marine basin over 1,000-550 million years ago. Folding, upliftment, and erosion resulted in sandstone mountains, granite plutons, and diverse mesoclimates and soil types.
Soil:
The Cape wine regions boast highly diverse soils due to topography and geology, impacting mesoclimate and vine performance. The coastal zone features sandstone mountains on granite intrusions, surrounded by shale at lower altitudes. Reddish and yellowish brown soils associated with granitic hills and sandstone mountains are weathered, acidic, well-drained, and water-retentive. Granite-derived soils on undulating hills exhibit coarse sand, gravel, and wet clay. Malmesbury shale landscapes with varying soil types surround granite plutons, with stony residual soils on hill crests and structured soils on slopes.
Three Important Soil Types:
1. Derived from Table Mountain Sandstone: Sandy with low nutrient and water-retention properties (Fernwood, Longlands, Westleigh, Dundee).
2. Derived from Granite: Usually red to yellow-colored, acidic, found on mountain foothill slopes and ranges of hills, with good physical and water retention properties (Oakleaf, Tukulu, Hutton, Clovelly).
3. Derived from Shale: Usually brownish, strongly structured, on partly decomposed parent rock, with good nutrient reserves and water-retention properties (Glenrosa, Swartland, Klapmuts, Estcourt).