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2.2.1. Ciply Formation - Ci

Authors: Le Hardy de Beaulieu (1861), Robaszynski (1988a).

Description: the Ciply Fm consists of a white-yellowish, marine calcarenite, with locally different silicification levels. The lime content is very high, attaining sometimes more than 99%. In outcrops the formation starts by a conglomerate, composed of fragments from the underlying Upper Cretaceous sediments: brown pebbles of phosphatic hardgrounds, more or less rounded, and phosphatised fossil fragments: the "Malogne Conglomerate".

Stratotype: not formally designated. The formation was most completely exposed in the now abandoned and infilled quarry "André" along the road from Mons to Bavay (Ciply). The most closely located outcrop is in the quarry "Vandamme", where at the base of the quarry the "Tuffeau de Ciply" and the "Poudingue de Malogne" outcrop in an approximately 10 m thick section (sheet 45/7-8, Mons - Givry). Coordinates: x = 119.39, y = 122.84, z = +60 m.

Area: the Mons Basin, in outcrops and in boreholes.

Members: the formation is not subdivided into members.

Thickness: some 20 m in the quarries of Ciply and more than 30 m in boreholes.

Age: Middle and Late Danian, based on planctonic Foraminifera.

Remarks: the formation is also discussed by Cornet & Briart (1866), Maréchal (1993), Meijer (1969), Rutot & Van Den Broeck (1886a, 1886b).