Ed. Vanriessen et N. Vandenberghe, AN EARLY OLIGOCENE OIL SEEPAGE AT THE SOUTHERN RIM OF THE NORTH-SEA BASIN, NEAR LEUVEN (BELGIUM), Geologie en mijnbouw, 74(4), 1995, pp. 301-312
A prominent chocolate-coloured horizon at the top of the Kerkom Sand (
Oligocene, Tongeren Group) near Pellenberg in the Leuven area (Belgium
), has traditionally been interpreted as the illuvial zone of a podsol
type soil. Observed features however are equally compatible with an o
rigin as an oil-saturated reservoir sand. In fact, organic geochemical
analyses indicate strongly that a fossil oil seepage is the most like
ly interpretation. The time of oil impregnation may be related to an i
mportant tectonic re-arrangement, which started at the very end of the
Eocene, and probably triggered the leakage and migration of oil from
traps in the southwest of the Netherlands. The oil migrated through po
rous sands up the gentle northern flank of the Brabant Massif, guided
by clayey seals till it reached the surface. The presence of a fossil
oil seepage in the Leuven area, means that possible traps, downdip of
the Pellenberg outcrop, may contain accumulations of oil.