|
|
|
Augen Gneisses at the stream
The Caroux Massif is famous for its
augen gneiss. We notice immediately the whitish inclusions in the
rock. The "augen" (yeux or eyes) are lozenge shaped light
white to light grey coloured inclusions in the rock of up to 4 x
8 cm. The gorge provides the best visible section through the gneisses
of the Caroux Massif (and the Montagne Noire as a whole). At this
location the gneisses with augen are seen within the massive boulders
in the stream.
|
| |
|
| One of the large
crystals at the centre of the characteristic augen of the area. |
| |
Recent
uplift?
The lowering of the bed of the stream will keep pace with any uplift
of the surrounding rocks and the probable recent cutting of the Gorges
is evidence of a Recent phase of uplift. The steep sides of up to
almost 1 km which we will see a little further on are a testament
to the young age of the gorge. The rugged sharp edged rock shapes
and the abrupt change in angle at the summit also point to recent
cutting of the Gorges |
|
 |
| Down at the stream, where a change
of rock type is very clearly seen in the boulders |
| |
The cutting action of
the stream
The stream looks gentle enough if you
are here in the summer, but the large boulders have been transported
down the stream. The grinding action of particles of all sizes lowers
the bed of the stream. |
| |
The age of the Gorges
The shape of the cross section of the gorges is that of a steep vee.
This, and the presence of large boulders are evidence of a rapid rate
of cutting for the stream. The rugged rock shapes and the sharp edges
of the top of the Gorges all point to a young age for the present
gorges which are likely to be only single figures of millions of years. |
| |
The augen described
The gneisses and their augen are described at the next Location |
|
