Boom formation clay-pits
Oligocène and early MIOCENE
Middle EOCENE sands
BRUXELLIAN and LEDIAN
THANETIAN
Middle and Late
55 million years before our era, a hot and not very deep sea recovers all our area. Sharks more adapted to the tropical climate occupy all the ecological niches, thus replacing the traditional species of the Paleocene one. The now inaccessible locality of Egem delivered to us many exciting testimonies of this past.
SELANDIAN
THANETIAN 2
NEOGENE
RUPELIAN
LUTETIAN 2
LUTETIAN 1
THANETIAN 1
The harbour of Antwerp is in constant enlarging. That made our deal well, bus of sands and gravels very fossiliferous dating from Neogene are located at about fifteen meters under the level of the ground, but also of water. Regularly, these sediments are dredged in great quantity and are spread out over plains before being re-used. The backup of these fossils depends on our community of paleontologists, quite active on this blow there! .
With the top of the clay of Boom, in the clay-pits close to Terhagen, lower Miocene sands have at their base a gravelly level containing of the remainders of Elasmobranchii.
Nearly 30 million years ago, a sea recovers all the north of current Belgium. In this rather calm water, very fine sediments brought by the winds settle in-depth. The sharks which populated it formerly left us some vestiges which one sometimes finds in the large clay-pits of the area of Boom.
Part of sands of Brussels were eroded. A new marine incursion involves a new sedimentation which begin with a basic gravel in which one finds remainders of fossilized sharks. The teeth are rolled a little, but beautiful pieces are nevertheless present.
Sands of Brussels recover most of Belgium. There are that and there shelly lenses containing sometimes teeth often in a superb state of conservation. The collectings spots are rare, after the filling of the majority of the sand pits of the Brussel's area.
At the end of Thanetian, the sea is withdrawn again. A large river is formed, carting lots of sediments which contain fossils of animals of marine and terrestrial origin. Many species of sharks had made their appearance or their return thanks to a more lenient climate. Some gravel pockets, vestiges of this Paleocene time finishing, remain hidden in the middle of nowhere.
A few million years later, a part of Selandian sands was eroded after the withdrawal of the Heersian sea. There some stones and teeth remained, cleaned by the rain and the winds, and the sea returns, leaving at the base of new sedimentary deposits a layer very rich in remainders of selacians.
The shore of a disappeared sea approximately 60 million years ago. In this cool and isolated water a restricted number of species proliferate without competition. Many clay pellets, mollusc shells and some remainders of vertebrate are gathered in lenses which will quickly be covered by other layers of sand. Thus one finds today marine fossils of Selandian in Belgium.
Requins fossiles de Belgique et d'ailleurs