Before talking about geology, it should be remembered that a "terroir" depends on a combination of several natural factors that endow it with its typical characteristics: geology, topography, pedology, climate and microclimate. While some factors are unchanging such as geology, others vary from one year to another such as the amount of sun or rain, which then combine with cultivation variants such as grape variety, the mix of grape varieties in a vineyard, pruning techniques and so on.All these factors add an extra dimension that is expressed in the vintage.
THE GEOLOGICAL CONTEXT OF WINE PRODUCTION IN BURGUNDYGeologically speaking, the Seuil de Bourgogne lies at the crossroads between the Paris Basin and the Bresse rift (the Saône valley) on one side and the Morvan (an outcrop of the Massif Central) and the Vosges mountains on the other. In terms of stratigraphy, this very particular position explains the variety of subsoils present which range from granite in Beaujolais to Quaternary alluvial deposits, with, however, a predominance of rock formations from the Jurassic period. In terms of tectonics, as a result of the N-S intra-continental rifting of the Tertiary period, the wine-producing region of today's Burgundy consists of a very narrow, gently folded fault zone between the carbonate-bearing Jurassic plateau in the WNW (outer edge of the Paris Basin) and the predominantly clay-based Tertiary deposits of the Bresse Graben in the ESE.
Quaternary glaciation also marked the region by carving out coombs with resulting alluvial fan deposits at their base. The vineyards of the Côte lie on limestone and marly rock formations from the Jurassic period that often incorporate rapid successions of lateral variations in facies within the same formation. These "rapid" changes, which occur both vertically and laterally, can be explained by the Jurassic environment which consisted of coastal areas of warm, shallow seas in a climate similar to that of the Bahamas today. These variations can therefore be explained by fluctuations in time and space between coastal areas, barrier zones, lagoons, reefs and areas more open to the sea. The notion of rapidity is all relative, however, as these series of rock formations from the Middle to Late Jurassic period were deposited over approximately 25 million years, between around 170 and 145 million years ago!
The stratigraphic difference between the Côte de Beaune and Côte de Nuits is explained by gentle N-S folding in the form of the Volnay syncline in Côte de Beaune which allows outcropping of Callovian and Oxfordian formations, and the Gevrey anticline which in turn exposes Bajocian and Bathonian formations in Côte de Nuits.