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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.