The large marshes of Chézeaux are home to the most beautiful alkaline peat bog in north-east France. Rich in history, this site is home to a remarkable array of flora and fauna, including ferns, reeds and dragonflies. Accessible via a duckboard path, the heart of the marsh is fed by formidable artesian wells with highly mineralised water.
The subsoil in this area alternates between impermeable rock (clay), which prevents water from passing through, and permeable rock (limestone), which allows water to circulate. In this context, rainwater infiltrates the permeable rocks. As it descends into the subsoil, it becomes trapped under a layer of clay, forming a captive water table.
At the bottom of the valley, this water escapes through discontinuities in the clay stratum, creating artesian wells. These wells, whose flow rate is estimated at several tens of litres per second, supply the whole of the large marshes. Despite their innocuous appearance, they can be more than five metres deep. The water they release is loaded with carbonates as it passes through the limestone rocks. On contact with air and vegetation, these carbonates precipitate, forming tuff. This substance blocks the decomposition of organic matter. Vegetation therefore accumulates, forming alkaline peat.
The accumulation of peat creates bulges in the marsh that can be seen on the access path. It also creates a curious situation: the peat accumulates around the wells, raising the soil in these areas. The wetlands are then found on the highest points, rather than in the hollows...
This site is protected by the Conservatoire d'espaces naturels de Champagne-Ardenne.
Les grands marais de Chézeaux
