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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.


Close up of large augen

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

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