Subsurface facies analysis of the Namurian and earliest Westphalian in the western part of the Campine Basin (N Belgium)

Abstract

Geophysical wireline logs from recent boreholes were used to unravel the sedimentary history of the Namurian and earliest Westphalian in the western part of the Campine Basin. The study comprises 4 wells with petrophysical data (Merksplas, Poederlee,DZH14, DZH15) and 1 corehole (Turnhout). Paleogeographical cartoons are presented for the studied interval together with some examples of the log-response of the sedimentary sequence. The pendleian is missing in the Campine Basin. The Namurian sedimentary sequence starts with Arnsbergian to Alportian basinal mudstones. These are followed by two turbidite-fronted delta sequences which prograded towards the north into the basin. From the late Yeadonian onwards, four successive shallow water sheet-deltas developed. The upper part of the earliest Westphalian Ransart Member is formed by braided river deposits, situated underneath the Finefrau Nebenbank Marine Band. This succession corresponds very well to the Namurian sequence of a marginal part of the English Pennine Basin, the Gainsborough Trough, although the timing of the events is somewhat different.