Château Fonbadet terroirs are located on deep, well-dissected gravel outcrops, at an altitude ranging from 14 to 22 metres. This is an average altitude for Pauillac outcrops (6 to 27 metres), where gravel from the edge of the terrace, characterised by natural drainage, abounds. According to the APIETA (Agricultural Association) map, identification and dating of the gravel soil at Château Fonbadet shows two distinct types of deposits. The Pouyalet outcrop was formed during the Mindel I Glaciation (600,000 BC), while the Saint-Lambert and Pauillac outcrops date back to the Mindel II Glaciation (450,000 BC).
These soils form the main geological component of Grands Crus Classés terroirs, from Margaux to Saint Julien and from Pauillac to Saint Estèphe.
Moreover, these gravel terraces, dating back to the Mindel period, make up the soil of all the Grands Crus Classés listed in 1855.