Let’s now profile the next unconformity in the sequence of pulses of erosion and deposition recorded in the North-West Highlands of Scotland. For a reminder, here’s a cartoon cross-section through the four relevant units: Today, we’ll look at the contact between the Lewisian Gneiss and the Torridonian Group (Diabeg Formation), marked with a “2” on … Read more
First in a series profiling the three unconformities to be found in the North-West Highlands of Scotland. Today: the sub-Stoer unconformity as exposed at Clachtoll. Explore a Proterozoic buried topography topped with coarse, angular breccia.
The isle of Jura in Scotland is where George Orwell wrote 1984. It’s just across a narrow channel from the eastern side of Islay, where I spent four lovely days geologizing this summer. Looking across the gap, you can see a cluster of prominent mountains on Jura. These are the “Paps” of Jura, and they … Read more
This is the Split Rock at Clachtoll, on the shore of the North-West Highlands of Scotland. You’re looking out to sea, over the Minch. It’s the site that graces the cover of the excellent book A Geological Excursion Guide to the North-West Highlands of Scotland, by Kathryn Goodenough and Marten Krabbendam. “Clach toll” apparently means … Read more
A quick Friday fold here from the North-West Highlands of Scotland: These are Lewisian gneisses exposed on a headland northwest of the little outpost of Tarbet (where the Handa Island ferry departs from). I was out there in search of shear zones, but I found plenty of nice folds, too. There are two main folds … Read more
Yesterday I showed you two scenes, depicted in two photos each, that I saw on the beach at Machir Bay, Islay, last week. I suggested that it might be fun to compare and contrast them. Scene #1 was this: Scene #2 was this: Scene #1 is a place where aeolian (wind) currents were at work. … Read more
Here are two scenes, depicted in two photos each, that I saw on the beach at Machir Bay, Islay, last week. Compare and contrast them. Scene #1: Scene #2: What stories do these pebbles tell? Answers tomorrow…
When in Shetland, one of my first stops was the museum in Scalloway, and one of the ancillary benefits of visiting there is the castle next door: Scalloway Castle includes building stones derived from the local limestone – a Neoproterozoic unit that has recently been chemostratigraphically correlated with Snowball Earth cap carbonates elsewhere in the … Read more
I’m in the North-West Highlands of Scotland, enjoying spectacular geology and less-than-spectacular weather. I’ve been fairly productive on the GigaPan front, regardless, nipping outdoors when the weather permits to shoot outcrops and landscapes. One set I’m particularly pleased with is this suite of four images. They show the Archean-aged Lewisian gneiss, the oldest rock unit … Read more
When I took you on a virtual field trip to Kinkell Braes earlier this week, I didn’t mention that the sandstones are folded there, now did I? Let me remedy that omission now: That is a plunging anticline that you could actually take a plunge into: And here’s a syncline to match. Happy Friday. Hope … Read more