4.1. ROMONT GROUP

Authors: P. Haesaerts, S. Pirson & E. Meijs - 07/12/2011

Description: Contains all loess units characterised essentially by silt size (mostly 16-62µm), an allochtonous mineralogy, a clay fraction originally ca. 10% but increasing to ca. 30% by weathering (clay illuviation in interglacial Luvisols).

Stratotype: Eben-Emael (CBR chalk quarry at Romont). The western (50°47'27''N / 5°38'37''E) and eastern (50°47'08''N / 5°39'27''E) walls of the quarry, corresponding to the limits of the exploitation, will be accessible in the long run. They are exposing both formations of the Romont Group easy of access on top of the fluviatile deposits of the Romont Terrace (Juvigné et al., 2008).

Area: Middle Belgium, on plateau and slopes.

Age: Middle and Upper Pleistocene.

Remarks: This group corresponds to formerly known Gembloux Formation (Gullentops et al., 2001; see Fig. Y). Recent fieldwork in Eastern Belgium, mainly by E. Meijs, lead us to propose the definition of two distinct formations in the loess belt: Veldwezelt and Gembloux Formations. The upper formation is largely distributed.

Figure Y. Lithostratigraphic units of the Belgian loess belt and comparison with former lithostratigraphic scheme of Gullentops et al. (2001).