Polurrian Rocks 12 – Close-up of meta-sedimentary rock from the Devonian Period 372 – 388 million years old Carne Formation on the north side of the Lizard Boundary Fault at Polurrian Cove in Cornwall.
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Jessica's Nature Blog 
What an interesting pattern. Do you have any idea why the rock looks like this, with the embedded red bits?
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I especially like this one. The peeling layers with the rusty spots appearing as surprises.
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I am not too certain, Linda. I haven’t managed to find an definitive explanation in the literature yet. They could be weathered remnants of a fine red layers like those illustrated in previous images. The colour makes me think they might contain iron. They look a bit like the siderite nodules (iron carbonate) that are found elsewhere in Carboniferous sandstones and limestones. The iron might itself be derived from organic decomposition sludge on the former seabed?
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Thank you. Claudia. The spots are an interesting presentation of the red material that forms fine sheets between the strata elsewhere.
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I’ve not seen rocks like this before.
https://looseandleafyinhalifax.blogspot.co.uk/
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Yes, the same for me, Lucy, though I have seen rocks of a similar date but different appearance on the north Cornish coast at St Ives. Cornwall seems to have a lot to offer in terms of rock types.
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Thank you very much for your photographs. I´m a spanish geologist currently working in Galicia, north Spain. I was just looking in the web for outcrop pics of the Gramscatho Gp. flysch rocks, because I have some not-well identified rocks probably a correlatable Devonian… grey to green greywackes and slates with candy-coloured quartzite thin beds, pseudo-pebbles and lenses… very close to your photographs! Thks again!
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Thank you again, Paco. I am pleased that my photographs were useful for your research.
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