Geopark LM 3 Englisch 2007.indd - Geopark Harz

Vision Jura Park
Oker limestone quarry
6
At the centre of Oker we turn to the left toward
Bad Harzburg. The straight road takes us to
the granite region of the Oker valley. Running
parallel to the Harzburger Straße is the
Harznordrand Thrust, apparent in the steeply
uplifted Adenberg – its rocks dating from the
Lower Devonian. After several hundred metres
we turn left in the direction of Harlingerode
and reach the entry drive of the Kalkwerk Oker
of the Rohstoffbetriebe Oker GmbH, at the
west end of the Langenberg. The gigantic farstretching
quarry faces of this quarry expose in
the south flank of the Langenberg, steeply Oker limestone quarry
over-tilted and dipping to the south, partly
dolomitic limestones and marl limestones of the Upper
Jurassic.
The large Langenberg outcrop area provides a unique view of
the strata sequence of the sediments tilted up along the
Harznordrand Thrust - it is a dominant landscape element.
Especially the limestone is particularly rich in fossils. In recent
years saurian bones have been discovered; this gave impetus to
the planning of a Jura Park. To visit the quarry it is mandatory
to announce your presence and obtain permission from the
plant management to enter the site.
A stop at the factory fence of the smelting
works west of the county road makes it possible
to study a well developed and most
varied example of Harz heavy metal vegetation
with Armeria halleri on heavy metal contaminated
ground. The North Harz is a European
major frequency area of plant families specially
adapted to living on metallic soils - an intriguing
environmental-geologic chapter of the
Rammelsberg landmark.
Armeria halleri
www.okerkalk.de
Quarz
Elfenstein
7
Returning to the Harzburger Straße we continue in the direction
of Bad Harzburg, turning off to the right at the Silberbornbad
(car park). We walk across the grounds of the horse racing track
and the manmade landscape of the stud farm pastures (worthy
of protection) which stretch out over the Jurassic and Triassic
strata hidden underground. We can see large quartzite blocks
lying alongside the road (bicycle path R1). At the edge of the
Harz we continue on foot in the same direction for another 600
metres into the Gläsekental Valley. There on the right-hand
side of the path we reach a small quarry in which a thick vein
of quartz has been exposed: the Elfenstein Vein. It continues
easterly upwards along the slope of the Elfenstein, where weathering
has formed it into cliffs. This quartz vein was inclined
in the wake of the Oker granite, therefore it must be of Late
Upper Carboniferous origin. This makes its course even more
interesting, as it runs parallel to the Harznordrand Thrust for
approximately three kilometres, thereby indicating that this
tectonic drift already existed in the late Variscan Era. So the
Harznordrand Thrust occurs on a very old structure.