The travertines of the Hoyoux - Marchin

The Hoyoux, over 29 km with the steepest slope in Belgium (from 290 m at the source to 75 m at the mouth), is known for its travertines, a rare phenomenon in Europe.

Just past the Ferme Château de Royseux along the Ravel line 126 towards Modave there are some very beautiful ones to admire. They are located on private property and are best admired when there are no leaves on the trees.

The traverine is a chalky dam that results in waterfalls . It can be defined as a sedimentary limestone rock formed by the rapid precipitation of calcium carbonate. There are 5 known major sales areas for traverine in Belgium. They are labeled as old because they no longer evolve, but in the Hoyoux valley some are still active, meaning that lime deposition is still taking place.

The sales areas are formed by a complex biological and chemical process . To be simple, the groundwater that feeds the Hoyoux flows through the limestone rock in the geological Condruze strata. When it reaches the surface, it absorbs CO2 . This then causes lime deposits . The activity of plants, algae, mosses, etc. also increases lime precipitation.

Historically, traverine was used for numerous purposes . This can be observed in the vaults in the Collegiate Church of Huy .

Willem Vandenameele