Geology

Geological map of Burgundy

During the primary era, the ground was essentially composed of granite. At this time the region's predominantly tropical climate caused the warm, agitated sea to advance eastward.

The sea covered the entire region nearly throughout the secondary era before slowly retreating. The secondary era is divided into three periods: Triassic, Jurassic and Cretacean. In receding, the sea left sedimentary rock that resulted in the make up of the soil of Burgundy today.

During the tertiary era the sea completely receded and the formation of the Alps was the cause of major tectonic shifts. Strongly felt in Burgundy, these movements were the origin of the fault that crosses the region North/South. The landscape of Burgundy has changed little since the birth of the Alps.

We are now in the quaternary era which began with the ice age. Burgundy, situated on the border of the icecap, was not covered by glaciers, however it did suffer a succession of freezes and thaws that affected the limestone. In spite of this its landscape was not transformed. Today we are in the second phase of the quaternary era, know as the Holocene.

The region is divided into five large geologically characteristic zones (see map) defined by the different soil compositions. 

See map of basins

Burgundy stone is extracted from different stages of sediment deposited by the sea during the primary era (Triassic, Jurassic and Cretacean periods). There are principally 8 strata that make up the local soil.

• Hettangian: (limestone formed with fossils) rarely found near the surface.
• Sinemurian: limestone formed by sediment used for building stone walls.
• Carixian: Excellent for farming, rich in phosphate, this strata is essentially composed of marl and clay.
• Domerian: a layer of clay several dozen metres thick ; the upper level is composed of limestone rock.
• Toarcian and Aalenian: Clay and marl often hidden under landslips ; these stages are usually covered by vegetation (forest).
• Bajocian: Among other layers, this is where oolithic limestone lies (extracted and exploited by several Burgundy Stone Assocation quarries)
• Bathonian: Containing few fossils this strata largely eroded during successive eras (Jurassic era).