TROPICAL
SEA, THE GERMAN GRAND CANYON AND ICE-AGE DUST. The
landscape today is dominated by the Upper Rhine Graben, a rift
in the earth’s
crust that started to form about 50 million years ago. During
the Oligocene (about 30 million years ago),
the region was flooded by a sea. The edge of the Taunus and
the Bergstrasse marked the coastline of this sub-tropical sea
in
which sharks and sea cows thrived. Although the sea existed
for only a few million years, it left many relics of its existence
in the Rheingau: beach gravel, marine sands, clay and limestone.
As the sea receded, the Ur- Rhine reconquered the rift valley,
flowing in a shallow valley through the lowlands of the Rheinische
Schiefergebirge towards the North Sea. During the Pleistocene (2
million years ago), the Rheinische Schiefergebirge was upthrusted
forming the mountain range we see today. The Rhine carved
its valley into the rising mountains forming the well-known
imposing steep-sided narrow valley – the Grand Canyon
of Germany.
The Pleistocene also
marks the beginning of the ice ages. The alternation
between cold and warm periods continues until today.
Our landscape was formed by intensive weathering and
deposition of loose sediments. The continuous freezing
and thawing of water fractured the rocks. Thick beds
of wind-blown dust along the slopes of the Rheingau
and Bergstrasse are an impressive testimonial to the power
of the wind during the ice ages. |
