The vineyards are situated between the Leitha mountain range and the Hainburg Mountains and are underlain on the one hand by deposits of the Paratethys Sea and the Pannon Lake and on the other hand, in the areas of the Arbesthal Hills and Prellenkirchner Flur, by glacial terrace gravels of the former valley floors of the Danube.
The deposits of the Paratethys Sea and Lake Pannon consist of diverse carbonate-rich, unconsolidated, sandy-marly or silty-clayey, but rarely gravel sediments. The deposits of the Danube terraces are quartz-rich, sandy-gravels. They all bear an extensive cover of calcareous-dolomitic, silty loess or rather clayey, often decalcified loess loam.
The Leitha Limestone formed on the coastline of the Leitha mountain range about 16 million years ago as a marginal marine deposit within the Vienna Basin. Vineyards at Hof and Ungerberg are located upon the Leitha Limestone.
In the Hainburg Mountains the deepest and innermost portion is formed of granite, which was intruded into existing gneisses. The high altitude Berg vineyard is located on this substrate. Calcareous-dolomitic carbonate rocks of Mesozoic age were then deposited on those rocks. They form the rock walls above Hundsheim and the summit of Mount Spitzerberg.
The south-facing wine growing area includes rocks that on the basis of their geological characters are attributed to the Variscan mountain range and the Molasse Zone. The Molasse Zone shows a marine development, from a sea which is called Paratethys by geologists, and a river landscape, which is characterized by the overlapping areas of influence of three river systems: the Kamp, Traisen and Danube rivers.
In the north, diverse and predominantly acidic crystalline consolidated rocks dominate that also have been noted in the Wachau and the Kremstal areas. A rock package that is quite unique in Austria occurs within a wedge at the Heiligenstein area: in this tectonic rift valley the first erosion products of the former high mountain range of the Bohemian Massif are found. They consist of conglomerates, sandstones, arkoses (red, feldspathic sandstones) and shales. The sediments were deposited before 320 to 250 million years ago mainly under arid-hot climatic conditions as a result of flash floods directed from the ancient mountains onto the foreland. A special feature worth noting is the occurrence of rhyolite pebbles within the conglomerate that prove the existence of volcanic eruptions.
In the Kamp Valley glacially derived loess deposits are again the most prevalent wine-growing rock.
The wine growing area of Kremstal is located on the south-eastern arc of the Waldviertel region and the Dunkelstein Forest. Formed of crystalline bedrock the area opens out towards the east into the Alpine Foreland where primarily unconsolidated rocks occur. This position facing away from the windward side of the crystalline highlands is responsible for the widespread and sometimes very thick loess deposits.
North of the Danube the slopes are formed of sometimes schistose, sometimes consolidated paragneiss that show amphibolite and granite gneiss inclusions. The slopes to the northwest consist of Gf?hler Gneiss. Granulite outcrops occur south of the Danube. The composition of the light-coloured, very hard granulite is related to the Gf?hler Gneiss, but it shows planar foliation.
Among the unconsolidated rocks calcareous loess is the more prevalent, which in places occurs in several layers one above the other. The loess can overlay the crystalline rocks as well as all the older gravel, sands and clays. The latter consist partly of marine deposits and partly of the alluvial Molasse sediments and the Danube River terraces. Only the deepest, flat-lying layers near the gravel floodplains of the Danube have no loess cover, but rather show a thin sheet of fine flood sediments.
The wine growing area of the Thermenregion extends along the eastern edge of the Calcareous Alps to the Vienna Basin. However, only a small proportion of vineyards are located directly upon consolidated limestone and dolomite rock or on the sandstones and conglomerates of the Gosau Group. Most vines are planted on deposits of the transgressing Paratethys and Lake Pannon within the Vienna Basin or on glacial river gravels in the plains of Steinfeld.
At the margin of the basin sands, gravels, sandstones, conglomerates and breccias are predominant. These are composed of rock material from the Calcareous Alps and flysch rocks and were transported by rivers from the uplifting Alps. Famous fossil sites are recognized within the sediments, such as the Gainfarn Sands, which contain molluscs, gastropods and corals and even a complete, about 14 million year old, sea-cow skeleton. In the basin the vineyards are often located upon fine-grained clays, marls, talus or colluvium, where loamy soils with high lime content often develop.
In the southeast, some vineyards occur on the other side of the Vienna Basin on crystalline schists and carbonates of the Austroalpine Superunit, which outcrops here in the Rosalia mountain range.
The most striking geological element is coarse, calcareous- dolomitic gravels, which were transported here by the ancient Traisen River, before about 16 million years ago, derived from the uplifting Calcareous Alps and deposited within a delta of the Paratethys Sea. The gravels have mainly been consolidated to conglomerates and occur especially on the elevated areas of the western slopes of the valley. On the right side of the valley, the older, so-called Oncophora-Beds dominate, which are now referred to as the Traisen Formation. These consist of calcareous, more or less silty and sometimes weakly indurated sands, within which the name-giving marine mollusc shell "oncophora" is found; locally conglomerates are intercalated within the sands. However, the two units together constitute only about twenty percent of the subsurface of the vineyard soils.
The vast majority of the vineyards are located upon loess, which on the left slopes of the valley is often penetrated by truncated conglomerate components.
In the westernmost part of the wine growing area the crystalline basement of the Dunkelstein Forest emerges as light-coloured, hard granulites, upon which the acidic vineyard soils are established, if loess was not deposited above the granulite.
Old, crystalline consolidated rocks form the steep slopes of the Danube Valley with for instance, various gneisses, amphibolites, marbles and quartzites. First and foremost is the finely convoluted Gf?hler Gneiss, followed by a variety, on the basis of composition and structure, of paragneiss and the hard granodiorite gneiss of Spitz. Basic rock layers in the form of dark amphibolites which originated as lavas from submarine volcanoes, often alternate with the paragneiss. Marbles with characteristic grey-white banding occur in the western Wachau area.
In the deeper part of the valley flank between W?sendorf and Wei?enkirchen there is an old landslide mass of weathered and chaotic layered rock and boulders. The plane of motion is marked by kaolin and red loam. Small remnants of gravels, sands, silts and clays, such as at Spitzer Burgberg and near Wei?enkirchen, belong to the Molasse Zone and formed from rivers and marine transgressions during the period between 30 and 15 million years ago.
Loess is often encountered in the Wachau area as a thin layer upon the older rocks. Coarse river gravels with a covering of fine flood sediments form the present valley floor of the Danube.
Loess is dominant north of the Danube and almost completely covers the basement consisting of crystalline rocks, silty-clayey marine sediments of the Molasse Zone and glacial terrace gravels. The yellowish flour-like and consistently calcareous-dolomitic rock dust is sometimes up to several meters in thickness here. In the northern, more elevated and hilly part of the wine growing area, the vineyards are located upon sandy- gravel soils that belong to the so-called Hollabrunn-Mistelbach Formation. These mark a former course of the Danube, which is about 10 million years old. In many cases the gravel shows a loam cover layer.
South of the Danube the vineyards are sited on the varied rocks of the Molasse Zone until towards the east the major location of Klosterneuburg is encountered. The vineyards here lay on diverse grades of calcareous flysch rocks. Characteristic and often repeating sequences of sand, silt, claystone and marl are referred to as flysch, which formed from submarine mudslides that flowed into the deep waters of the former Ocean.
The north-east facing underslopes are coated by fine-grained, more or less calcareous loams.
At the edge of the Waldviertel region, the vines stand upon the acidic granite of the Moravian Superunit which weathers to quartz-rich sand. To the east two basins consisting of unconsolidated rocks occur. These are separated by the ridge of the Leis Mountains and the striking klippes of the Waschberg Zone formed of light-coloured, hard limestone. The central part of the Weinviertel region also has occurrences of the flysch rocks in the south with calcareous sandstones and marls at Bisamberg while acidic, quartz-rich sandstones and shales are more commonly found on the eastern edge of the Korneuburger Basin.
West of the Waschberg Zone we find the Molasse sediments with sand, gravel, clayey silts and a remarkable diatom horizon on the one hand and on the other hand the broad gravel ridge of the ancient Danube.
The region east of the Waschberg Zone forms part of the Vienna basin and is also predominantly composed of unconsolidated, mostly calcareous rocks such as gravel, sand and clayey silt. Consolidated limestone or calcareous sandstone only occurs locally in both basins.
More than half of the vineyards are located on loess: the glacial rock dust which can cover all the older rocks in varying thickness and then also provides a source of calcium on acid substrates.