Sardinian geology and the art of protest

It’s been a while since I’ve had time to post, but as I’ve got everything I need to done before buggering off on a well-earned Christmas break, I thought I should take the opportunity to post some stuff I’ve been meaning to for ages.

Back in October my beautiful lady and I went off to Sardinia for a week of R&R. Seeing as she also did a degree in geology she is very accommodating of my need to go and bother some rocks when I’m somewhere new. I had little time to do any research before we went, so all I knew was that the geology was supposed to be pretty good. that is a significant understatement. It was incredible, and I have every intention of returning to properly recce for setting up a field trip there.

Our transport for the week. possibly the most horrible vehicle I've ever driven.

We were based on the Eastern side of the island, and the mountain roads mean getting anywhere is a drive. Possibly a drive and a bit. We barely looked at the West of the island at all, but the East and central regions were phenomenal. Just within the town we were staying there were sedimentary, igneous and metamorphics to look at. The following is a taster, just from the small bay at the Northern end of Cala Gonone, a 5 minute walk from where we were staying.

The first thing that caught my eye was this rather spectacular wave-cut platform, exposing a columnar-jointed outline of vesicular basaltic lava.

This stuff was everywhere. Where it oucropped in the cliff further down the columnar jointing was more obvious

We wandered another 50 meters along the cliff edge, and I realised that I was standing on something quite different. Sunglasses for scale (easy way to differentiate holiday geology from work geology).

One fossiliferous limestone. However, in the cliff behind it we had this:

One classic lava flow, with both rubbly top and rubbly bottom, and large vesicles formed by outgassing volatiles. These have been stretched as the lava flowed.

With a so clearly igneous rock so close to a clearly sedimentary one, it was incredibly satisfying to take a step back and see something really quite cool.

One contact metamorphic aureole. In the background is the lava, and I’m standing on the fossiliferous limestone. Between the two is a gradational change from unmetamorphosed limestone at the foreground, to marble at the background, highlighted beautifully by the colour change.

So, igneous contact with sedimentary rock, full contact aureole visible, with 100% exposure, in a hospitable climate, with cold beer within 100 m.  If that’s not a perfect locality for a field trip I don’t know what is.

Before I sign off, I also though I should also highlight the non-geological but still frankly awesome stuff we saw at Orgosolo, in the centre of the island.   They have a tradition of political graffitti in several towns in Sardinia, but never have I seen stuff quite like this.  The town is literally plastered with images like those below.  I won’t add any commentary,a s I think most of them speak for themselves.  This is but a small selection of my favorites – there’s a fuller set here.  Happy Christmas, and see you in the New Year!

About Pete Rowley

Earth Scientist with a background in volcanology and sedimentology. Enjoys a good rant, beer, and games. Dislikes reality TV, crowds, and unreasonable people.
This entry was posted in Geology, Science, Sedimentology, Travel, Volcanism and tagged , , , , , , , , . Bookmark the permalink.

1 Response to Sardinian geology and the art of protest

  1. I like your post. It’s very interesting and informative!

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