2.4 Röt Formation

Authors:  Stainier,  1907,  1943; van Adrichem  Boogaert & Kouwe, 1993.

Description: red, partly bleached sandstones and shales, partly with gypsum nodules and veins, with subordinate gypsum beds and grey marls.

Boundaries: top: passing into Muschelkalk Formation; base: overlying Bree member of Buntsandstein Formation.

Stratotype: Parastratotypes  in  Belgium:  well  KB3l Elen , well KB64 Rotem.

Area: Roer Valley Graben; removed by erosion from Campine Basin .

Thickness: ca. 125 m .

Age: Lower/Middle Triassic (Scythian/Anisian) transition , unspecified.

Remarks: First formal  description  of the Röt Formation in Belgium. The stratigraphy of the red sandstones in the Belgian part of the Roer Valley Graben is hardly known , though it is probable that the gypsum-bearing red sand­ stones and shales belong to the Solling and Röt Formations of the Upper Germanic Trias Group, according to the  Dutch Stratigraphic Nomenclature. However, the contact with the underlying Buntsandstein Formation , supposedly along Hardegsen Unconformity which marks the boundary between the  Upper  and Lower Germanic Trias Groups, has not been recognised and total thickness of the Triassic sandstones thus is not known with certainty.