Geology

 

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 BURGUNDY

Geologically 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. 

GEOLOGY OF THE DOMAINE PONSOT VINEYARDS

Spread around the villages of Gevrey-Chambertin, Morey-Saint-Denis and Chambolle-Musigny, the estate's vineyards lie on Bajocian and Bathonian rock formations which repeat themselves like piano keys as a result of the large number of small-throw faults.    As a general rule, because of the gentle N-S fold resulting in outcrops of Bajocian and even Late Lias series at the Gevrey Brochon anticline, the vines around Gevrey are on Bajocian rock, those of Morey on Early Bathonian and those of Chambolle on Bathonian.  

AROUND GEVREY

The Chambertin grand cru grows on Bajocian crinoidal limestone which is also fed with significant amounts of Ostrea acuminata marls as a result of the slope.    The Chambertin satellite grands crus to the east of the Route des Grands Crus, Griotte and Chapelle in this instance, also lie on crinoidal limestone, but the ground is less sloping and the influence of marls is therefore insignificant. The Gevrey Village appellation sits on the Oligocene infill of the Bresse rift as it is located just to the east of the Saône fault. This infill is made up of conglomerates, limestone and clay. Because of its position at the foot of the slope, the ground is nevertheless also strewn with crinoidal limestone debris.

AROUND MOREY

The Clos des Monts Luisants perfectly illustrates the complexity of the fault patterning here: the upper part (down to the little château) grows on the compact Bathonian limestone of the Comblanchien, the middle part on white oolite, and the lower part on Premeaux limestone. Because of the very steep slope, Comblanchien debris is found on the oolite section and oolite rubblerock on the Premeaux section. The Clos de la Roche comes from two vineyards separated by a path: the vines to the west of the path lie directly on Ostrea acuminata marls with outcropping of Premeaux limestone in the upper part which feeds the marly soil with limestone debris, and the vineyard below the path sits on crinoidal limestone, with significant additions of Ostrea acuminata marls from the upper vineyard. Premeaux limestone is the substrate of the Clos Saint Denis.

AROUND CHAMBOLLE

Les Charmes is a premier cru which, like the neighbouring Les Amoureuses grand cru, illustrates the impact of the Quaternary periglacial period: these vines sit on the alluvial fan downstream of the Ambin coomb and the substrate consists of periglacial red alluvium greatly enriched with the Bathonian limestone rubblerock forming the plateau: it consists mainly of Comblanchien limestone and a small amount of white oolite.