Friday, 18 June 2010


Volcanism in the Hérault dates back at least 30 million years. The most recent active volcano was by the coast at Agde, today a familiar rounded hill topped with a fat transmitter tower, that finished erupting a relatively recent 0.5 million years ago. Agde marks the southern end of a line of volcanoes that started some 2.5 million years ago in the Larzac and Lodèvois. Less than 30 Km north of Agde around Aspiran the last eruptions have been dated at 0.7 million years ago.

Making a point. Philippe Martin of the Association of Ecologistes de l'Euzière and author of La nature méditerranéenne en France (see here on Amazon).

In his hand is a piece each of basalt and limestone.
On the left in the background is the Roc du Caylar.

Perhaps surprisingly, what remains from this activity is relatively unspectacular scenery for the area. The cliffs of the Roc du Caylar above Nebian (see picture above) and the tooth like Pic de Vissou above Cabrières are eye grabbing rocky landmarks, but were never volcanoes. All erosion has left is a couple of rounded hilltops 5 Km from Aspiran above Lieuran-Cabrières towards Peret.

Maluber (also known as Malhubert) is on the left and Maugno on the far right. The hill between them in the centre is unnamed. Aspiran is behind the camera.

Same view taken from the pine trees south of Aspiran.

Pic de Vissou from Maluber. Vissou is not a volcano but was formed by folding of the land - rather like a swiss roll bursting open when the sponge won't flex.

Maugno viewed from near the col between Maluber and Maugno.

In their day these were what are known as Strombolian volcanoes, picture postcard cone shaped and complete with craters. This type produce lava flows that cool to give relatively pure dark basalt rock. One particularly large flow went as far as the Hérault valley (5 Kms). Today it’s a mainly wooded whaleback ridge that can be seen on the left after one passes the cemetery on leaving Aspiran en route to the main road - the top ends near the water tower. During the eruption the lava would have flowed down the valley of the river Dourbie, but subsequent erosion has left the harder basalt rock as a ridge and the Dourbie now flows to the north east.

Aspiran from the 316m summit of Maugno. The lava flow is out of picture to the left.

The edge of an ancient quarry with Aspiran in the background.
Basalt is more durable stone than limestone, but for most less attractive. Buildings in the area are constructed using a mixture of both giving a speckled appearance, although much of Agde, including the large church, are entirely basalt giving the town a somewhat gloomy feel on dark wet days.

Further down the Hérault valley there’s a large working quarry at Lézignan-la-Cèbe where an even larger and longer 10 Km lava flow ends having emerged from the volcano Les Baumes above Fontès.

These vines are on the basalt lava flow about 500m from the end of the flow at the old quarry. Large boulders of basalt can be seen forming a bank at the back having been removed from the vineyard as they would wreck a plough. Sites like this are being sought after by modern wine makers as the basalt gives the grapes and resulting wine a refreshing acidity.

Close up these ancient volcanoes are more spectacular. There are areas with boulders of basalt like the vineyard picture above. In places volcanic “bombs” of rock are spewed all over the land like natural litter – the result of molten rock meeting water under the volcano. Elsewhere the basalt has weathered and been coated with attractive orange/yellow lichens, there are some specs on the quarry picture.

Botanically this is known as garrigue and is packed with herbs and flowers such as thyme, mint, camomile along with less well known Mediterranean species like thé de garrigue (Sideritis romana). A massive subject.

No comments:

Post a Comment