MV Geology Map
The result of decades of diligent investigation by curious geological scholars, this map provides a key to the complex, constantly unfolding links between geology and modern wine flavours.The time gap between this ancient geology and modern human endeavour is breathtaking to behold. Some of the tocks discussed here are from ages when multicellular life was beginning to evolve, aeons before today's veil of agriculture was cast over the landscape. This document will help to explain how different geological terranes influence wine flavour.
The McLaren Vale Wine Region is located 30km south of Adelaide and lies mainly within two triangular basins. The southerly Willunga Embayment is defined by the Willunga Scarp to the southeast the hills beyond the Onkaparinga Gorge to the north, and Gulf St Vincent - coincidentally the patron of viticulturers - to the west. The northerly Noarlunga Embayment is similarly bordered by the Ochre Cove - Clarendon Scarp and Gulf St Vincent. These basins have been filled with layers of sediment deposited on ancient bedrock over the last 45 million years by the constant advances and retreats of the sea. These layers can be observed during a stroll along the seashore from Maslin Beach to Port Willunga, and from Christies Beach to Seaford.
White settlers first encountered the Willunga Embayment in 1837 when a party of marines led by Colonel William Light and JH Fisher, Resident Commissioner, rode south to settle a dispute between whalers at Encounter Bay. After camping overnight at Nrlongga, a Kaurna word meaning 'place on the river curve', they crossed the stream called Ngangkiparringga ('women's camp on the river'), climbed the southern embankment, and marvelled at the vast fertile vale spread before them. They would surely take deep satisfaction to stand there again, gazing over the quilt of prosperous vineyards dotted with tidy estates and busy villages.
VITICULTURE
Grapes are tiny bags of sweet-and-sour water. This water comes through the vine roots, with the flavour influenced by the organic and mineral composition of the ground.
Viticulturers have long been concerned with soil types. But to the geologist, soil is the result of surficial weathering of underlying rocks by the action of water, atmosphere, soil organisms and changing physical conditions. Road cuttings at Mclaren Vale reveal that soil is usually a thin overlay on parent rock which the cine roots quickly encounter. Hence the need for this geological map.
By 2010, McLaren Vale has been regularly producing from 50,000 to 70,000 tonnes of wine grapes per year from 7388 hectares of vineyard. Since the beginning of the colony, this fine wine has been exported across Australia and the world.
Typical of the cycles of history, after nearly two centuries of curious experimentation with many newly fashionable grape varieties, local vignerons often find their best results are with varieties that were wisely selected by the first settlers. The visionary John Reynell, for example, by 1862, was making respected wines from Cabernet Sauvignon, Malbec, Tempranillo and Pinot gris, from vineyards established in the late 1830's. At the same time, Edward John Peake was growing Shiraz, Mourvedre, Carignan, Grenache, and other Mediterranean coast varieties.
This document will assist viticulturers to match the many grape varieties, old and new to the various terranes of this uniquely beautiful, bountiful wine region.
