Sign in

Pete Bowden

@peterlbowden1.bsky.social
392 followers 157 following 180 posts

Mylonites, migmatites & metamorphism. With some pseudotachylite thrown in for light relief.

PostsRepliesMedia
Pete Bowden @peterlbowden1.bsky.social · 10h
I loved reading to my son, it was a night-time ritual. All too soon he wanted to read to himself.
110
Reposted by Pete Bowden
Oliver Strimpel @geologybites.bsky.social · 02/10/2026
🧪⚒️Tiny grains of coesite — quartz that forms only at pressures found about 100 km down — turned up in rocks of western Norway. On the new Geology Bites, Torgeir Andersen explains how buoyant continental crust got that deep, and how it came back. geologybites.com/torgeir-andersen #geology
Eclogite in Vårdalsneset, in the Western Gneiss Region of Norway.  In the Western Gneiss Region of Norway, eclogite occurs in pods within the prevailing grey granitic gneiss.  The pale green matrix is omphacite, a sodium-rich pyroxene, studded with dark red garnets.  The rock began as a gabbro or dolerite intruded into Baltican continental crust long before the Caledonian orogeny, and was converted to eclogite when that crust was dragged to great depth.  As Andersen explains in the podcast, eclogite is denser than the mantle; its "life belt" is the lighter granitic gneiss that encloses it. Ultrahigh-pressure metamorphic rocks around the world.  All were formed by subduction zones, and most lie in mountain belts built by continental collision, such as the Caledonides, the Alps and the Himalaya.  Most formed within the last 540 million years or so.  The oldest, in Brazil and Mali, are about 650–620 million years old; the youngest, in the D'Entrecasteaux Islands of Papua New Guinea, described in the podcast, are less than 10 million years old.

Compiled from:
Liou, J.G. et al. (2004), International Geology Review, 46, 1
Liou, J.G. et al. (2009), Journal of Asian Earth Sciences, 35, 199
Warren, C.J. (2013), Solid Earth, 4, 75, and subsequent reportsA) During the Scandian collision — the final phase of the Caledonian orogeny, when Baltica itself collided with Laurentia — about 435–405 million years ago, the leading edge of Baltica — the Western Gneiss Complex (WGC), shown in pink on the map above, together with the rock sheets already stacked on it — was dragged westward beneath Laurentia by the sinking plate it was attached to.  Higher rock sheets were thrust eastward over Baltica, building the wedge labelled at the top. The dashed line marks the surface along which the buried rocks, in its footwall, would later return, sliding up past the hanging wall above. 

Brueckner, H.K. et al. (2013), Lithosphere, doi: 10.1130/L256.1(B) By about 405 million years ago, the descending slab had broken off.  As Andersen explains in the podcast, once released from its heavy anchor the buoyant continental crust rose back along the former subduction zone, while the whole mountain belt stretched and collapsed, bringing the ultrahigh-pressure rocks up to shallow depths.  Note that green here is the mantle, not the rock sheets shown in green on the map above.
273
Pete Bowden @peterlbowden1.bsky.social · 28/09/2026
Hope you remembered your library card😉
010
Pete Bowden @peterlbowden1.bsky.social · 17/09/2026
@frankrennie.bsky.social Right up your street, with language, story telling and a bird. There is a link in the editor's notes at the end which will open up a warren😉
020
Pete Bowden @peterlbowden1.bsky.social · 17/09/2026
Thank you for giving me an interesting start to the day.
010
Reposted by Pete Bowden
Adrian Littlejohn @yorksfella59.bsky.social · 07/09/2026
I am bloody proud to be an #RNLI supporter and member! These brilliant men and women have quite enough to cope with without being harassed by the scum of the earth. Their only concern is to help people in danger at sea - not check passports first! Which is how it should be. Please RT if you agree🙏
541003569
Pete Bowden @peterlbowden1.bsky.social · 29/08/2026
Great ALT text - thank you
010
Pete Bowden @peterlbowden1.bsky.social · 19/07/2026
@scotfot.bsky.social
010
Pete Bowden @peterlbowden1.bsky.social · 12/07/2026
👏👏😍
030
Pete Bowden @peterlbowden1.bsky.social · 06/07/2026
The Vetch was the name of the football ground where Swansea originally played. Maybe named after this plant?
000
Pete Bowden @peterlbowden1.bsky.social · 27/06/2026
Avoiding tropical nights 😅 was a consideration when we moved to the Outer Hebrides🌧️
110
Pete Bowden @peterlbowden1.bsky.social · 26/06/2026
Many happy memories of a week mapping in the snow, on the northern flanks of Schiehallion. April, 50 years ago, a structural geology mapping assessment before our final exams😵 We also stopped to admire that commemorative plaque.
030
Pete Bowden @peterlbowden1.bsky.social · 12/06/2026
Like our front garden, (no ferns though), in the Isle of Lewis.
Purple marsh orchids with yellow buttercups in a lawn in the Isle of LewisA mass of yellow buttercups with quite numerous purple marsh orchids in a lawn.
120
Pete Bowden @peterlbowden1.bsky.social · 10/06/2026
Luckily I never encountered that opportunity, so we had to lug the sediment sampling kit, up the streams ourselves💪.
020
Pete Bowden @peterlbowden1.bsky.social · 09/06/2026
Was a volunteer in the BGS geochemical survey team which sampled that area in the 1970s.
220
Pete Bowden @peterlbowden1.bsky.social · 02/06/2026
Congratulations
010
Pete Bowden @peterlbowden1.bsky.social · 27/05/2026
Still running Quicken at home on a Winsows XP desktop.
000
Pete Bowden @peterlbowden1.bsky.social · 26/05/2026
Croft XLII😉
010
Pete Bowden @peterlbowden1.bsky.social · 14/05/2026
For me it was charnockite😉
020
Pete Bowden @peterlbowden1.bsky.social · 10/04/2026
Inside the neighbouring Leacanabuaile ring fort.
Two people stand inside the remains of a stone building inside an Irish ring fort called Leacanabuaile.
000
Pete Bowden @peterlbowden1.bsky.social · 10/04/2026
Inside Cahergal - stepped walls provide easy access to top for defenders.
Two people have climbed to the top of the inside wall of this ancient Irish ring fort, using the stepped construction.
000
Pete Bowden @peterlbowden1.bsky.social · 07/02/2026
Same in the Outer Hebrides - virtually no rain. The strong and cold easterly wind does make for some spectacular breaking waves with the spray being blown backwards.
A large wave is breaking with a fine white cloud of spray being blown backwards by a strong wind.
030
Pete Bowden @peterlbowden1.bsky.social · 05/02/2026
Is there any riebeckite granite on the island? A very long time ago I was taught that the blue pleochroic amphibole in the curling stones from there was riebeckite.
110
Pete Bowden @peterlbowden1.bsky.social · 05/02/2026
Expensive though.
010
Pete Bowden @peterlbowden1.bsky.social · 31/01/2026
I wonder if the uppermost hinge is part of a thrust related drag fold, which post dates the other near isoclinal fold. There looks to be dislocation in the top right quadrant of the photo.
000
Pete Bowden @peterlbowden1.bsky.social · 27/01/2026
Beautiful example of undulose extinction in that little fish - I really miss having a microscope😞
120
Pete Bowden @peterlbowden1.bsky.social · 21/01/2026
This looks like one of the stones at Callanish on the Isle of Lewis. It is a fine example of Lewisian gneiss, but hides a secret on the other side😉
120
Pete Bowden @peterlbowden1.bsky.social · 01/01/2026
And a Happy New Year to you as well. May your lenses remain dust free😀
010
Reposted by Pete Bowden
Kim Cobb @kimcobb.bsky.social · 17/12/2025
It is hard to overstate how critical @ncar-ucar.bsky.social is to climate science in the US and around the world. It's the beating heart of our field. Generations of scientists have trained there, and almost everyone I know relies on deep collaborations with NCAR scientists. It's end is unthinkable.
27550274
Pete Bowden @peterlbowden1.bsky.social · 07/12/2025
These are very common in the Outer Hebrides where I live, known as "runrigs" or "lazy beds". Frustratingly they are so common that I haven't bothered to photograph any examples🤦‍♂️ I believe remnants can be found throughout the British Isles.
010
Pete Bowden @peterlbowden1.bsky.social · 02/12/2025
I have done a few photo books in the last couple of years which is a good way of selecting the most important digital photos from amongst the thousands I have on my computer.
010
Pete Bowden @peterlbowden1.bsky.social · 02/12/2025
During COVID times l digitised all my photos and those I inherited from my parents. I can't bring myself to throw out the hard copy prints though.
120
Reposted by Pete Bowden
The Megalithic Portal Ancient Sites & Stones @megalithic.bsky.social · 26/11/2025
🏆Win🏆the perfect Christmas 🎄 gift for a stones enthusiast: STONE LANDS (on the Waterstones and Telegraph Best Books of 2025 lists) AND ALSO THE OLD STONES (The Megalithic Portal guide, winner of Current Archaeology Book of the Year) To win a signed (and dedicated if you like) copy of both books… 1/
Win a copy of STONE LANDS (on the Waterstones and Telegraph Best Books of 2025 lists) AND ALSO
THE OLD STONES (The Megalithic Portal guide, winner of Current Archaeology Book of the Year)
28254
Pete Bowden @peterlbowden1.bsky.social · 07/10/2025
Chlorite, biotite, muscovite
020
Pete Bowden @peterlbowden1.bsky.social · 21/09/2025
I used to just varnish the cut surface on the best looking "half".
100
Pete Bowden @peterlbowden1.bsky.social · 25/08/2025
We haven't established enough windbreaks yet and our fruit trees are still young. Storm Floris stripped our outdoor beans and spuds😱
110
Pete Bowden @peterlbowden1.bsky.social · 25/08/2025
The plum harvest😋 is one of the few things I miss, having moved from Enderby to the Outer Hebrides.
110
Pete Bowden @peterlbowden1.bsky.social · 21/08/2025
🟩🟩🟩 with envy.
110
Pete Bowden @peterlbowden1.bsky.social · 18/08/2025
In the skiing season they take their arguments to Slovenia, which provides endless entertainment in the queues for the ski tows.
110
Pete Bowden @peterlbowden1.bsky.social · 12/08/2025
Yup, finishing off my son's Slovenian horse burger was an unexpected highlight of our holiday 🤣
110
Pete Bowden @peterlbowden1.bsky.social · 09/08/2025
The city built upon Slovenian oak?
120
Pete Bowden @peterlbowden1.bsky.social · 09/08/2025
A very popular choice on the Student Association jukebox (remember those?), back in the early 70s at Dundee. Unfortunately I can't find my copy of the "Best of Mountain" LP, but I remember it being a favourite of mine.
120
Pete Bowden @peterlbowden1.bsky.social · 08/08/2025
The Lewisian, (part of the Pre-Cambrian), is named after the Isle of Lewis in the Outer Hebrides and the Caledonian mountain chain is named after the Latin name for Scottish Highlands.
000
Pete Bowden @peterlbowden1.bsky.social · 07/08/2025
🤣
010
Pete Bowden @peterlbowden1.bsky.social · 27/07/2025
I saw my first rhyolite in Glen Coe😃⚒️
031
Reposted by Pete Bowden
Rhyolite_Prof @edithrojas.bsky.social · 26/07/2025
Geology people who do we you know in Edinburgh so that we can connect and go to Siccar point together. Do your thing social media!!!
41611
Pete Bowden @peterlbowden1.bsky.social · 15/07/2025
One of my favourite Scottish mountains with fantastic Dalradian geology on the northern flanks.
 The snow covered triangular peak of Schiehallion on a bright spring day.
060
Pete Bowden @peterlbowden1.bsky.social · 12/07/2025
I moved to the Isle of Lewis to get away from the heatwaves😅🤦‍♂️
010
Pete Bowden @peterlbowden1.bsky.social · 12/07/2025
Yes😀 Taken there, in the mid 70s, as an interesting historical diversion whilst on a geological field trip around Ben Lawers and Glen Lyon.
020
Pete Bowden @peterlbowden1.bsky.social · 11/07/2025
I knew if I kept watching your posts for long enough I would get an identification for these beautiful flowers spotted near Mealasta slipway😀
Bright yellow flowers amongst the grass on the headland north of Mealasta slipway, west coast of the Isle of Lewis.
Look like the Bog Asphodel, (Blioch in Gaelic), in a recent post by Frank Rennie.
010