XFrom water to rock again, and this time foreign rock which is how Xenolith translates.

I must admit, when I first thought of using xenolith for my X post, I was thinking of those strange boulders that are found miles away from where any rock like them forms part of the landscape.  Many of those have been moved by ice, as in glaciers, but they are properly termed erratics.  Cornish stone They are great natural phenomena (that being my A to Z theme this year) and sometimes lead to artificial phenomena like stone circles and piles.  I’m particularly fond of this one, in Cornwall, which I stopped and drew a picture of many years ago, now.  I think my friend Helen bought it.

Xenoliths are fragments of rock that become embedded in other rocks – usually through rock formation under the Earth’s crust (igneous rocks).  They can also be embedded in sedimentary rocks, chunks covered by decomposing animal skeletons and laid down over the millennia to become limestones and the like. The most common xenoliths are in granites.  There is a lovely grey granite – Shap granite  (in the header picture) – with pink rock captured in it that is quarried in the Lake District.  I think the pink bits are actually autoliths, in that they are made from the same material as the surrounding rock, but crystallised faster.

This picture is of xenoliths; the embedded rock is older than the surrounding rock.

xenoliths hull

Take a look at the monuments around you.  There might be interesting things in the stone, apart from graffiti. The photo above is of xenoliths in the stone of monument buildings in Hull (courtesy of East Yorkshire RIGS Group).  And if you ever visit the Albert Hall in London, cross the road to the Albert Memorial and look at the paving around the base of the memorial – it is stuffed with fossils and xenoliths!


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19 thoughts on “Xenoliths

  • 28 April, 2015 at 11:02 am

    I studied geology very briefly years ago but don’t remember this. And I think I recognise Lanyon Quoit in your picture!

    • 28 April, 2015 at 2:11 pm

      Thank you so much! I couldn’t remember its name and didn’t have time to look it up!

  • 28 April, 2015 at 12:52 pm

    Very interesting! thanks for sharing! I love all the new blogs that I’ve found during this A-to-Z. I’ll never get caught up on my reading 😉

    • 28 April, 2015 at 2:12 pm

      I know just what you mean, Shawn – thanks for visiting and remember, there’s always the Road Trip to take at your leisure through the year!

  • 28 April, 2015 at 3:26 pm

    Love that stuff! Sedimentary rock can have some amazing stuff…let me see if I can post of picture of some cool conglomerates from Death Valley…don’t think I can put that into the comments.

  • 28 April, 2015 at 4:07 pm

    I don’t think I’m ever again going to pass a monument without making a closer inspection. This was fascinating. Clearly I’m going to have to go back and read more of your posts once the challenge winds down.

    • 28 April, 2015 at 8:43 pm

      You’ll be very welcome, Kern!

  • 28 April, 2015 at 4:53 pm

    I love your posts – I’m learning so much!

    • 28 April, 2015 at 8:44 pm

      Just reciprocating your educational value 😀

    • 28 April, 2015 at 8:44 pm

      He’d probably improve them, too!

    • 28 April, 2015 at 10:27 pm

      lol… glad you think so… I detect a note of desperation in there myself!

      • 28 April, 2015 at 10:29 pm

        Hey, it’s X. And I didn’t actually expect to find it interesting, so there’s that.

    • 29 April, 2015 at 4:15 pm

      Sure is, Yvonne!

  • 17 May, 2015 at 12:16 pm

    Hi Jemima – came across Xenoliths on Friday … and I posted about Lanyon Quoit on my N for Neolithics post … as it’s been part of our lives as my mother’s family comes from St Ives/Penzance …

    The earth and its creation with all the rocks etc is incredible .. I love finding out more .. cheers Hilary

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