A day of geology on the coast of southwestern France

June 2nd, 2017

La Barde, France — Today we traveled west to the Gironde Estuary on the southwest coast to continue our survey of Campanian fossils. It looks like we will be working on the sclerobionts found with the extensive Pycnodonte oyster beds. Macy is above examining one of the best exposures of these fossils at a roadcut above Plage des Nonnes.

Our first stop was a roadcut in Mortagne of the Segonzac Formation, the oldest of the Campanian units we’ve seen so far.

The next outcrop was of the Biron Formation at the southern side of Caillaud. It is flanked by a salt marsh, with more open ocean conditions farther along.

Macy stands here on the fossiliferous Biron Formation at Caillaud south.

Another place where the ocean would love to kill me.

The Caillaud north locality was very fossiliferous, including excellent cheilostome bryozoans like Onychocella above. Despite the diversity of fossils here, there aren’t enough encrusted and bored oysters for us.

The cliffs just south of Plage des Nonnes. Definitely a location to visit at low tide.

These are some of the abundant Pycnodonte oysters we saw in the roadcut above Plage des Nonnes. We will certainly return to this outcrop later.

Besides the research, there were of course many other sites of interest. I took several images of this salt marsh at Caillaud south, for example, to use in my Sedimentology & Stratigraphy course.

We found this large jellyfish at Plage des Nonnes. The thickness and rigidity of the “jelly” is amazing.

This is the Talmont church perched on an outcrop above the sea.

The Romanesque, intricately carved entrance to the Talmont church.

It was an excellent day of culture and geology in France!

Location GPS Unit Position
Mortagne 160 Segonzac – lower N45° 28.763′ W0° 47.496′
Cliff north of Mortagne 161 Segonzac – upper N45° 28.963′ W0° 47.943′
Caillaud south 162 Biron N45° 31.805′ W0° 53.629′
Caillaud north 163 Biron N45° 31.916′ W0° 54.206′
Plage des Nonnes 164 Aubeterre N45° 33.534′ W0° 57.895′
Roadcut above Plage des Nonnes 165 Aubeterre N45° 33.627′ W0° 57.894′

 

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