Location 1.

St. Thibéry

The first outcrop to consider is in the town of St. Thibéry It is situated in the streets of the town and is surrounded by houses.

Outcrop 1

• This outcrop is an excellent example of columnar cooling joints.
• This is a basanite, which is an undersaturated alkali-olivine basalt.
• The whole outcrop is about 30m wide and 8m in height.
• The outcrop is of Pleistocene lavas.
• The whole outcrop has probably formed from one flow.

Picture 1:

This picture shows columnar jointing. Click on the image to enlarge

From the picture it is evident that there are different type of textures within this one flow. The bottom of the outcrop exhibits thin "bedding" (possibly flow jointing), which is contrasted by the very thick "bedding" which sits on top of it. These two sections appear to be smooth on first glance, however they are very vesicular. The top section of the outcrop is rubbly, and may represent the top of the lava flow.

Now proceed to Location 2.

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