Resulting from a rich geological past, the Garonne or Günzienne gravel outcrop of Château Carbonnieux has been home to vines for over seven centuries. For over seven centuries the vine has dug its roots and shaped the sub-soil of this domain.
A rich geological inheritance
At the end of the tertiary and beginning of the quarternary era , in the middle of the Pyrenean uplift, the Garonne river and its tributaries carried along the left bank from the south-east of Langon to Bordeaux large quantities of stony alluvium mixed with sand , silt and clay.
Over geological time these stones known as gravel (graves) were deposited on the river slopes forming several layers of terraces about 15 kilometers wide.
Two types of gravel covered the layers of sedimentary limestone:the Pyrenean sandy clay gravel at the end of the tertiary era and the Günz Garonne gravel of the quaternary era. The vine growing region south of Bordeaux gets its name from these.
A unique gravel outcrop
The specific morphology of the outcrop making up the Château Carbonnieux terroir can be explained by the runoff that removed the gravel layer deposited on four faces during the Quaternary era. A cap of massive gravel, that was relatively unaffected by erosion, today occupies the top of a strongly eroded gravel terrace.
The edge of the Carbonnieux gravel terrace consists of a belt of sandy gravel soils that moved due to the runoff.
Its slope, close to the main drainage axis, consists of a resurgence of the tertiary clay-limestone substratum, sometimes covered by migrant sands. The south-west of the estate is original in that a tongue of Landes sands blown in by the wind was deposited on the limestone base.
The outcrop and its appendages are drained thanks to many drainage pathways. This natural drainage of the soil ensures good water stress of the vineyard in the ripening phase.