Download Geological Open-air Exhibition - Nationalpark Bayerischer Wald

www.nationalpark-bayerischer-wald.de
How are rocks spread over the National Park?
Among the basic rocks of gneiss
and granite, other minerals were
incorporated in the course of the
Earth’s history. Fissures filled up
with minerals either molten or
dissolved in hot water.
These rare stones can only be found
in small channels. A map of how
rocks are spread over the National
Park is shown in the Geological
Open-air Exhibition.
How do rocks fall apart?
What is soil composed of?
Granite and gneiss weather only
very slowly. For that reason, granite is used as material for cobble
stones, gravestones or grave monuments.
In the course of thousands of years,
frost and heat, water and ice even
loosen the structure of this truly
hard stones. They fall apart into
smaller pieces and eventually decompose to sand. This happens
especially quickly within a stream,
where the running water first
rounds the stone and then forms
pebbles. But also the water contained in the soil breaks up the combination of cristals, when it is freezing and decomposes the individual cristals. Hard rocks become mellow and decompose. Wind and
climate gradually make round the
rocks at the surface.
If you dig a hole in the forest, you
will not meet solid ground until
very deep. Above, there is a layer of
weathered, decomposed material.
The closer you come to the surface,
the more the decomposed rocks are
mixed up with decayed plants (humus), with creatures and roots. On
the soil’s surface, there is more or
less decayed waste of plants, such
as leaves, needles or the remains of
cones. In accordance with the local
conditions, these decaying plant
materials are broken down quickly
or they pile up to mighty layers of
peat as in the bog areas. The layer,
bustling with live, made of remains
of rocks, humus, adobe and roots, is
called soil.
In the Geological Open-air Exhibiton there is a little steep slope kept
open permanently to grant insight
into the “underground”. The “outcrop” shows typical cambisols.
No wonder worked by nature, but a witness of the Earth’s eventful history.
The fissure of a coarse-grained granite was filled up by molten rock millions of years later,
which then solidified as a fine-grained granite (aplite).
What do rocks consist of?
All rocks in the Bavarian Forest are
formed of cristals. In case of the
granite, the more or less big and
grain-shaped cristals are visible to
the naked eye. The large, white
graines, which look like pieces of
speck in black pudding, are feldspar. Quartz is clear, glass-like or
milky. The tiny packets of dark or
bright discs are called mica. The
latter are used to glimmer ostentatiously in the sand of streams,
that’s why it is called “fool’s gold”
or “fool’s silver”. Feldspar, quartz
and mica are the most important
components of our local rocks. In
addition to those, a great number
of other minerals can be found,
however, in small amounts only.
The Geological Open-air
Exhibition is well accessible
to buggies and wheel chairs.
Pegmatites feature giant grains. The
individual cristals, like this Muskovite-mica,
can be easily recognised.
Please comply with the following rules:
Granites do not feature foliation, but are
grainily structured
Published by the Bavarian Forest National Park, December 2004
Visitor Facilities
Geological
Open-air
Exhibition
Lusen Granite
Younger Granite
with Cordierite Cristals
Redwitzite also called
from Finsterau
Syenite Granite
Older Granite
with Cordierite Criskorntals
from Finsterau
Granite
Rocks
Pegmatite
Quartz
Amphibolite
Serpentinite
il
So
ly
ar
g
Weatherin
Rare
Stones
Redwitzite or Syenite
arth
History of E
-E
Gneiss
with Metapegmatite
and Metaaplite
il
Loop Trar exhibition
l Open-ai
Botanica
Red Granite
changed in a
hydrothermal way
Information
Pavillon
Various Granites
Transitions
Contact Areas
erals
The information pavillon is in the
centre of the exhibition and informs on the following topics:
- History of Earth, formation of
stones,
- the upfolding of mountains,
- stones of the Bavarian Forest
National Park,
- decomposing and weathering of
stones,
- formation of soil and different
types of forest soil in the
National Park.
The underground of the Bavarian
Forest is formed of rocks, parts of
which are already more than 500m
years of age.
At first glance, the Bavarian Forest
seems to be formed of granite and
gneiss only. Looking at more throroughly, however, many rare stones can be discovered apart from
the main components; also it becomes obvious that these granites
and gneisses can be of different
compositions.
For example the gneisses of which
Mt Rachel and Mt Falkenstein are
formed, are of another consistence
than the ones which are around
this information centre or in the
Rocky Hiking Area. The finegrained granite of Mt Lusen falls
apart into relatively small, but hardly weathering boulders, whereas
the coarse-grained “Finsterau”granite in the eastern part of the
National Park forms large, rounded
boulders.
Min
How did the Earth come into existence? How were mountains folded? How are stones formed and
how are they decomposed? Which
rocks and minerals are there in the
Bavarian Forest National Park?
Find the answers to these questions in the Geological Open-air
Exhibition around the information
centre Hans-Eisenmann-Haus at
Neuschönau. It facilitates the access into the regional geology.
Ancient Stones
-Late
Regional Geology
pressure release
chemical weathering - dissolution
rubble
Orthogneiss
sand
Weathering
Information
Centre
Hans-Eisenmann-Haus
“decomposing”
Granite aplite
Schist
(Mica Gneiss)
Soil
Anatexic
blastomylinitic
Gneiss
Outcrop
with cambisols
Cordierite-sillimanite Gneiss
(surroundig the information centre)
Gneiss of Mt Rachel
Gneiss
Gneiss
very strong “foliated”
Geological
open-air exhibition
Gneiss
with calcite silicate
Gneisses are mainly recognised by their foliation - here an especially beautiful example