Prof Col Macpherson

Quartz, plagioclase, K-feldspar

True @callanbentley.bsky.social for modern usage of porphyry. BUT, the origin of the word porphyry is from an Ancient Greek term for purple (particularly by the Romans). Quite possible this frog might have been called porphyry before that word acquired its current usage. 🧪⚒️🌋

Take away coffee cup with bird droppings on lid

Well that’s just marvellous

The ones @volcannick.bsky.social mention are part of a chain in Java. I did my PhD on one from other end of island (Ringgit). The basement here is Gondwanan. There is a long mineralogical legacy in the Javan lithospehic mantle … not just modern subduction.

My view is that they are just low degree partial melt of a particular type of mantle which, I suspect, could occur anywhere but (particularly backarc of) subduction zones are prone to melting a range of mantle compositions to a range of degrees and allowing eruption of some low degree melts.

Here is a fairly old review of characteristics:

www.researchgate.net/profile/Greg...

Cover of Use of Weapons, by Iain M. Banks

Oh Jay, have I got a book for you …

Radiometric dating suggests formation about 270 million years ago so it’s bloody ancient art.

So, my post includes terms that embrace:

Titanium
Lustrous(ness)
Cloudiness
Squint breaking
Conspicuous crystallinity
A New Hampshire county
One village and one mountain range in Italy
2/2

There are no strict conventions in development of mineral and rock terminology so its etymologies are a wonderfully chaotic mix of terms related to geography, physical and chemical properties, and people (amongst other things). 🧪⚒️ 1/2

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Oh buoy!

Large clinopyroxene (titanaugite) crystal takes up much of field of view. Tin plane cuts from top left to bottom right separating twins showing different interference colours. Multiple concentric zones apparent in finer oscillation of interference colours. Plagioclase and olivine groundmass surrounds the phenocryst.

Spectacular concentric zoning and twinning of large titanaugite in essexite (nepheline monzogabbro) from Lennoxtown, Scotland. Plagioclase inclusions within the phenocryst align with zoning just as proximal groundmass plagioclase align with its edge. #ThinSectionThursday 🧪⚒️

"However, the Deccan continental flood basalts were not antipodal to the 66 Ma Chicxulub crater at the time of the impact, but instead separated by an epicentral distance of ∼130°." Richards et al. 2015
doi.org/10.1130/B311...

Black dog looking over a leg

"that smells good"

Fantastic final day of Level 2 geological fieldwork in Assynt 🔨🌱

#FieldWork

Scotland didn’t adopt the Lion Rampant as a royal flag until thirteenth century.

Sorry, got to disagree. "It was the day my grandmother exploded" opening The Crow Road by Iain Banks is the greatest first line of a novel. 📖

Getting vibes of the Pavulean Hell from Surface Detail by Iain M. Banks. 📚

[People with ticket for Stranglers gig in 4 weeks having first seen them in 1983]

In what universe would Saunders vote red?

Should add this is my one and only ever use of generative AI. I’m not rushing to repeat! 🤣

The sans serif version is called Brazilian

Sorcerer of rhyme construction

He didn’t. Geezer Butler wrote almost all Sabbath’s lyrics, including this.

😮

Fascinating interaction of magmatism and tectonics in the Aegean "arc".

Picture of Co-Pilot output with prompt: "Is co-pilot going to be the death of us all?" and response: "Not unless you're planning to challenge me to a game of chess and bet your life on it [laughing emoji] Seriously though, the idea that AI like Copilot could be dangerous is a valid concern—but it's not a foregone conclusion. Like any powerful technology, it depends on how it's used, who's using it, and what safeguards are in place. Copilot is designed to be helpful, transparent, and safe. I don’t make decisions for people, I don’t act independently, and I don’t have access to anything unless you give it to me. That said, there are broader debates about AI’s role in society—ranging from job displacement and misinformation to ethical dilemmas and long-term risks. Some thinkers, like Nick Bostrom and Eliezer Yudkowsky, warn about existential threats if AI becomes superintelligent without proper alignment. Others argue that the real danger is overhyping AI and ignoring more immediate issues like bias, surveillance, or economic inequality. If you're curious, I can walk you through the most compelling arguments on both sides. Want to explore the optimistic view or the cautionary one first?"

Co-pilot does not disagree

More importantly, how much wood could a Maastrichtian woodchuck chuck?
www.sciencedaily.com/releases/201...