Terroir 2004 banner
IVES 9 IVES Conference Series 9 An overview of geological influences on South African vineyards

An overview of geological influences on South African vineyards

Abstract

The role of soils and bedrock geology has long been acknowledged as a fundamental component of terroir. In South Africa the influence of geology is misunderstood and some important geological components will be highlighted in this paper.
In South Africa’s Coastal Region the oldest rocks comprise the Late Proterozoic – Cambrian shaley sediments of the Malmesbury Group, and the Cambrian age granitic intrusives of the Cape Granite Suite. Locally these are overlain by sediments of the Klipheuwel Group. These units are unconformably overlain the Middle Ordovician–Early Carboniferous Cape Supergroup, whose basal portion comprises the sandstones of the Table Mountain Group which produce the dramatic mountain scenery of the area.
The Breede River Region covers the valley of the Breede River, to the east of the Coastal Region. The Worcester fault is the major feature defining the geology of this area. To the east of the fault the geology is essentially similar to the Coastal Region. To the west the upper portions of the Cape Supergroup, the Bokkeveld and Witteberg Groups, are present comprising sandstone and shaley sediments. Late Carboniferous–Permian age sediments of the Karoo Supergroup overly the Cape Supergroup and Upper Jurassic-Early Cretaceous sediments of the Uitenhage Group are preserved locally as unconformable remnants.
The following geological features are important for the Coastal Regions vineyards. Soils are often acidic and potassium rich, whilst granites weather to produce both saprolites and kaolin, which are possibly unique in terms of vineyard soils. River gravels are noted in two scenarios, firstly vineyards are planted in river floodplains and secondly fossil gravel terraces exist above the current river level.
In the Breede River Region river gravels are important whilst a significant portion of vineyards are planted on loam soils containing calcareous layers. These calcareous layers are formed as a result of excess evaporation over precipitation in this low rainfall region. A geological control may exist for the formation of these calcareous layers above specific bedrock strata. These soils are unique in the South African context, as they are naturally alkaline.
In addition topography resulting from differential weathering of the geological units is significant in the local terroir. Factors such as warm or cool slope orientation and the effects of altitude on mean temperatures and rainfall are important.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

C. J. Bargmann

Geological Consultant, 5, Allt-y-Wennol, Pontprennau, Cardiff, CF23 8AS, United Kingdom

Contact the author

Keywords

Terroir, wine, geology, South Africa, Coastal Region, Breede River Region

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Climate change – variety change?

In Franconia, the northern part of Bavaria in Germany, climate change, visible in earlier bud break, advanced flowering and earlier grape maturity, leads to a decrease of traditionally cultivated early ripening aromatic white wine varieties as Mueller-Thurgau (30 % of the wine growing area) and Bacchus (12 %). With the predicted rise of temperature in all European wine regions the conditions for white wine grape varieties will decline and the grapes themselves will lose a part of their aromatic and fruity expression. Variety change towards the cultivation of later ripening white wine varieties is a very expensive and long-term process, and must be accompanied by special marketing efforts.

Protection of grapevines from red blotch by understanding mechanistic basis of its infection

Currently, grapevine is host to a large number of pathogenic agents, including 65 viruses, five viroids and eight phytoplasmas. Needless to say, these pathogens, especially viruses responsible for several ‘infectious degeneration’ or ‘decline’ cause great distress to wine makers and grape growers, let alone the large economic losses incurred by the wine industry. A recent addition to this wide repertoire of grapevine viruses is a new viral disease known as Red Blotch in viticulture parlance. Its causal organism, Grapevine red blotch associated virus (GRBaV), discovered in 2008 is a newly identified virus of grapevines and a putative member of a new genus within the family Geminiviridae.

Could intermittent shading, as produced in agrivoltaics, mitigate global warming effects on grapevine?

Global warning increases evaporative demand and accelerates grapevine phenology. As a consequence, the ripening phase shifts to warmer and drier periods. This results in lower acidity and higher sugar levels in berries, yielding too alcoholic wines with altered organoleptic properties. Agrivoltaics, which combines crop and renewable energy production on the same land using photovoltaic panels, emerged as a promising innovation to counteract these impacts by partially shading the plants.

Optimizing protocol for a rapid and cost effective DNA isolation for Marker Assisted Selection pipeline

Grapevine is a plant that holds significant socioeconomic importance due to its production of grapes for fresh consumption, wines, and juices. However, climate changes and susceptibility to diseases pose a threat to the quality and yield of these products. The breeding of new genotypes that are resistant/tolerant to biotic and abiotic stresses is essential to overcome the impact of climate changes. In this regard, Marker-assisted selection (MAS), which uses DNA markers, is a crucial tool in breeding programs. The efficiency and economy of this method depend on finding rapid DNA isolation methods.

From precursor identification to the study of the distribution of 3-methyl-2,4-nonanedione in red wines and spirits

Prematurely aged red wines are marked by intense prune and fig aromatic nuances that dominate the complex bouquet that can be achieved through bottle aging.