6.1. Belle Roche Breccia - BRB
Authors: Paproth et al., 1983.
Description: Breccia composed of limestone or dolomite boulders, some of them reaching thousands of cubic meters (“rafts” of non-brecciated limestone). The Belle-Roche Breccia is not defined here as a formation because it originated by solution collapse of evaporitic layers in the Terwagne Fm which affected various other formations. Therefore it has no lithostratigraphical value.
Stratotype: Belle-Roche quarry, at Fraiture (Sprimont), on the north side of the Amblève valley (CSA).
Area: The breccia occurs in the eastern part of the CSA.
Thickness: About 40 m in the Belle-Roche quarry. The base of the breccia is always situated some metres above the base of the Terwagne Fm. Locally (Comblain-au-Pont), it extends up to the top of the Lives Fm, so reaching a thickness of about 200 m.
Age: At least post-Livian, possibly post-Visean.