I’ve been busy researching and writing a book on the formation of the sequences of Burgundy (and other projects) so I haven’t posted anything here for several years. Apologies, I tend to be uber-focused. That said, I sent out an educational writeup of Puligny for work, so I thought I would share it here.
First, there is this map, which I constructed by overlaying three different maps. The first is a satellite image of Puligny Montrachet. The second is a section of the Cartes géologiques, a geologic mapping of France that the French government produced in the 1970s. Then lastly, I overlayed a vineyard map. These drawn maps are rarely accurate, so this was a bit of a painstaking process. What I was attempting to do is discover what geologic features existed in each vineyard in Puligny. This kind of work has been done with meticulous core samples by Francois Petit-Vannier, so we do know that in Gevrey and in Marsannay, for instance, there a progression of Bajocian strata that don’t appear in Puligny, as they remain buried underground), but the Bathonian sequences stack upon themselves as the slope of Puligny rises toward the top of the hill.
Above Puligny Perrieres, the map indicates a touch of j2a though it is not color-coded. J stands for Jurassic, while 2a is the code for Premeaux limestone. Premeaux is the stone that covers all but the top of Ruchottes-Chambertin in Gevrey. It is a hard stone that formed in a reef environment.
Oolite blanche (j2b) formed next during a time when 20-50 feet of seawater covered this land. Calcium carbonate “oolite” pebbles were pushed here location by waves and currents, forming shoals that would become cemented the carbonate secretions of cyanobacteria. The Oolite blanche seen here is the same sequence that is found on the lower slopes of the Le Musigny in Chambolle-Musigny.
The sea-level would fall once again, and as it rose in places, muddy bays formed, often loaded with oysters. This mud became calcareous marl that we see at the center of Chambertin and Clos de Beze. But for whatever reason, in Puligny, those marls were lost to currents of water movement of subsequent sea rises and sea falls, as they do not appear in enough quantity to appear on the Cartes géologiques map.
The famed Comblanchien came next (J2c), and it can be seen in the upper sections of Folatieres and covers most of Chevalier-Montrachet. The middle Bathonian was a period of a great Burgundy reefal platform, which, as the water level fell, it allowed the platform to grow for hundreds of kilometers until it “bridged” to meet a similar platform growing out from the Swiss Jura. The waters over this platform were shallow, always less than 15 meters (50 feet), which was the maximum depth that most corals (that built the platform) could survive in the clearest of waters.
Next came the Dijon-Corton limestone (j2d) of the late Bathonian through to the early Callovian. These are similar to the Oolitic limestone of the early Bathonian, occurring as shoals the same conditions in the same depth of water. These limestones were named because it was first recognized as the formation appeared to begin in Dijon stretching to Corton, where it “disappears” south of the hill of Corton. This is that same sequence, though sometimes it is referred to as Calcaire bicolor.
Hugely underestimated are the swaths of areas marked by Roman letters. The fields marked J is limestone rubble that was weathered by periglacial and freeze-thaw, and erosion, during the Ice Age, cutting the east-west valley that forms St Aubin and others. This material is limestone and clay-based, mixed with silt from the flooding of Dheune and Saone rivers. This sequence extends midway up Bien Batard, Clavillon, and Puligny Perrieres.
Above that is Terres pied de la Cote, or the land at the foot of the Cote (marked by V). This soil type includes the soils of Le Montrachet, Pucelles, and Meursault Charmes. It has a lot of marly clay, increasing in limestone content and becoming rockier toward its upper sections. None of these great vineyards are set into a bed of limestone; instead, marl is king here, extending downward for two to three meters (6-12 feet).
Lastly, above most of the premier crus are the vineyards that are full of scree (E) (éboulis) a mass of rock and fallen earth that has landed in the upper vineyards of at the upper reaches of Puligny and Meursault, at Blangy and Meursault Narvaux, Tillet, etc.
So that is an overview of the geology of Puligny Montrachet.
Dean
Diary of a Winebuyer 