Geology of the wine-growing regions
Niederösterreich (Lower Austria)
Lower Austria includes the following large geological units: Moldanubian Superunit, Moravian Superunit, Molasse Zone, Vienna Basin, Waschberg Zone, Flysch Zone, Northern Calcareous Alps and the Central Eastern Alps. Quaternary deposits such as fine-grained loess and coarse-grained terrace gravels, which are significant for wine growing, may overlay all the main geological units.
Loess forms the initial material of the deep soils which show a varying calcareous-dolomitic content for just over half of the vineyards in this area. Almost one third of the vineyards are located upon deposits of Neogene age within the Molasse Zone and Vienna Basin. Aside from locally formed marls and sandstones, conglomerates and the Leitha Limestone, the dominant rocks here are unconsolidated. They vary from clayey silt to sand to gravel and rock debris in all proportions and can also differ greatly in carbonate content.
Just over six percent of the vineyards are located on soils overlaying crystalline bedrock of the Bohemian Massif. These areas are dominated by acid gneisses, granites and granulites. Especially in the units with abundant schistose paragneiss, alternation with amphibolite layers is often common and somewhat less frequently with marble layers. Features worthy of particular mention are the remnants of the first erosion episode of the uplifting high mountain ranges of the Bohemian Massif, which are preserved in the so-called Zöbing Formation of late Palaeozoic age.
Burgenland is from a geological point of view formed from the Styrian and Pannonian Basins and from the Austroalpine and Penninic Superunits. The Austroalpine Superunit consists of several nappes and through tectonic windows the lower levels of the Penninic Superunit are exposed. The deposits of the Quaternary are particularly common in the north of the country.
Over 60 percent of the vineyards in this area are dominated by diverse, coarse-grained, calcareous sandy gravels deposited along the ancient course of the Danube. Particularly noteworthy is the Seewinkel gravel, which underlays about a third of the vineyards. These gravels are only covered locally by fine sediments. In the older terraces a loamy, often lime-poor cover layer is widely distributed.
A good third of the vineyards are located on deposits of Neogene age within the basins. The deposits vary greatly, both with regard to grain size distribution, carbonate content and grade of consolidation: The spectrum ranges from partly silty, sometimes almost pure and non-calcareous clays in Central Burgenland to the consolidated Leitha Limestone.
The proportion of wine growing areas sited on consolidated rocks is low, but includes a colourful range: dolomite and limestone, calcareous-, clay- and mica schists, gneisses, amphibolites and serpentinites.
Styria, in the area of the Central Eastern Alps, is formed from the geological Penninic and Austroalpine Superunits. Among others the following belong to the Austroalpine Superunit: the Northern Calcareous Alps and the crystalline rocks in the areas of Jogllandes, Sausal and the Koralpe mountain range. Lowlands form the basins in the Mur- and Mürz valleys and the Styrian Basin. The wine growing area is situated to the east and south, where the Central Eastern Alps disappear under the Styrian Basin, which extends eastwards to the great Pannonian Basin.
About three-quarters of all vineyards in Styria are sited on deposits of the Styrian Basin, about 20 percent of the vines grow on consolidated rocks of the Austroalpine Superunit. A small proportion of the vines occur on mostly coarse-grained alluvial deposits, which are concentrated in the basin.
Special features to note in the area are the volcanic basalts, scoria and tuffs of the south-east sector, which underlay about three percent of the Styrian vineyards. The remaining basinal deposits vary both in grain size, carbonate content and grade of consolidation. They range from silts and marls to sands, gravels, boulder debris, sandstones and conglomerates and locally occurring limestone.
The diverse rock types occurring in the vineyards in the area of the Central Eastern Alps include gneiss, mica schist, phyllite, amphibolite, rare marbles and limestones.
The vineyards at Bisamberg, in Dobling, Dornbach and Ottakring are situated upon the consolidated rocks of the Penninic Flysch and intercalated coloured marls as well as on marginal marine sediments of the Vienna Basin which is of Neogene age.
The flysch consists of partly calcareous and partly quartz-rich sandstones with marl and clay layers. The deposits of the basin margin are composed of consolidated limestone (Leitha Limestone), of unconsolidated but mostly coarse sand and gravel and rarely of marl, which were deposited about 16 to 12 million years ago. The substratum of the vineyards in Mauer and Kalksburg are also formed from marginal sediments of the Vienna Basin. These developed due to deposition by rivers and debris flows from the Vienna Woods of sandy-gravel which solidified as conglomerates or breccias.
The vineyards in Stammersdorf, Hungerberg and in Oberlaa are located on terraces representing old Danube levels and consist of quartz-rich gravels with a loamy surface layer and a base formed mostly of sandy-gravel or fine-grained sediments, referred to locally as Tegel, of the Vienna Basin.
The hard cliffside rocks that make up the western and central part of Austria are highly diverse and include the following geological compounds: Moldanubicum, Molasse Zone, Eastern Alps with the Northern Kalkalpen (lit. Limestone Alps) and the Central Eastern Alps, Penninikum with flysch rocks, Helvetic and Subpenninikum. As in Eastern Austria, young sedimentary basins and geological even younger, quaternary, deposits of gravels, sands, silts and clays are found in the Alps. These sediments and particles were deposited across all peaks and troughs into the present valley and lake areas. In the cold periods of the Quaternary, large parts of the highlands were widely glaciated several times over, only the northern parts of Upper Austria and Eastern Carinthia were the last glacier high ice-free state. There are large gravel terraces and, in Upper Austria, also loess and loam sediments. In the mountainous regions, however, the young sedimentation is localised and very diverse in content.