THE CRETACEOUS PERIOD IN THE
NETHERLANDS
If you want to look for fossils in Holland,
you have to go to the deep south. In the province of Limburg you
find deposits from the Upper Cretaceous Period. These limestone
deposits contain a variety of fossils from about 70 million years
old. The most famous fossil ever found in Holland is a complete
skull of a Mosasaur. However in 1998 there was a new discovery. This time it was
a new species: Prognathodon saturator Dortangs et.al, 2002. A
cousin of the Mosasaurus hoffmanni. This earlier piece was taken to France
by Napoleon in the early 19th century. What is the reason for the
presence of these limestone deposits in The Netherlands? During
the Upper Cretaceous a transgression was in progress, submerging
our entire country. A thick sequence of chalk and limestone
sediments with silex was deposited. Because of the existence of a
landmass called the "Brabant Massif", deposits of
littoral sands and biodetrital limestone were formed. The "Brabant
Massif" almost totally submerged during these trangressions.
Because of strong tectonic movements in the south part of our
country, the basins formed in the Jura and Lower Cretaceous
Period, were lifted up. Because of that, these older deposits of
Jura and Lower Cretaceous sediments were strongly eroded and were
buried by 1500 meters of sediment. These tectonic movements
continued for some time and differences in the amount of uplift
created different rates of erosion. So in the southwest part of
the province of Limburg we find some slightly younger deposits
than in the southeast of The Netherlands. Under the influence of
research done in Germany, Staring (1860), a Dutch geologist,
placed these deposits in the Senoon, which includes the following
ages: Santonian, Campanian and Maastrichtian. He also divided the
Upper Cretaceous Period into four local deposits. In the nearby
Belgium area, the Belgian scientist Dumont (1849) placed a big
part of these local limestone deposits in the "Systeme
Maestrichtien". This "Systeme Maestrichtien"
became under the influence of research of micropaleontologists a
type locality called: "Maastrichtian", which was
recognized by the IUGS (International Commission on Stratigraphy)
in 1849. A new name was given to the four local deposits
mentioned above:
- Formation of Aken
- Formation of Vaals
- Formation of Gulpen
- Formation of Maastricht
- K/T boundary
Formation of Aken
This Formation is placed in the Upper
Santonian. These deposits appear mainly in the eastern part of
the province of Limburg and are nowhere complete. As a direct
result of the tectonics in this area, they are in discordance
with each other or are eroded. These deposits were formed as
marine deposits under strong tidal movements. Petrified wood is the most common fossil from this Formation.
It can
be found in the "Sand of Aken member" just on the other
side of the border with Belgium in an old sand quarry.
Formation of Vaals
The base of this Formation is formed by a conglomerate of
coarse sand with glauconite and quartz and is placed in the
Campanian. These deposits were formed in a shallow sea with
probably no or little tidal movement. It is a very rich deposit
of fossils. One can find lots of shells e.g.: Glycymeris geinitzi,
Cytheria ovalis, Trigonia vaalsensis, Aporrhais nilssoni, etc.
Formation of Gulpen
The lower part of this Formation is formed by marine limestone
deposits with alternating glauconite sands and silex. It was a warm and open sea
at that time. These deposits are mainly situated in the southwest part of
the province of Limburg. This Formation is placed in the Upper
Campanian and Maastrichtian. This Formation is very common. In
the main quarries in the area, these are the deposits which are
exposed. Because of their origin, open sea deposits, one can find many
fossils like echinodermata, sponges, ammonites, belemnites and
brachiopods.
Formation of Maastricht
This Formation exists of limestone with silex, hardgrounds and
very coarse detritus limestone and represents the top of the
Cretaceous deposits in the Netherlands. It is placed in the
Maastrichtian Age. The Formation of Maastricht is best exposed in
the limestone quarry ENCI in Maastricht. The type locality,
described from this quarry, was named after the city of
Maastricht in the south of The Netherlands. In the quarry one can
find many fossils, especially echinodermata, brachiopods,
belemnites, shark teeth and some vertebrates like Mosasaurus hoffmanni and
Prognathodon saturator. On a rare occasion one can find a fish.
K/T boundary
In 1999 a major discovery was made in the passage-ways of
the old quarry. The famous K/T boundary was discovered which was
thought to be eroded in this part of The Netherlands. It marks
the boundary between the Mesozoicum and Tertiair. An example of
this boundary is shown in the picture below.
}
The K/T boundary at Stevns Klint in Denmark !
More about the geology of the Netherlands and the latest news: please visit
the Natural History Museum Maastricht, Netherlands.
|
