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Prof Col Macpherson @colinmacpherson.bsky.social · 14h

Likewise, this is more the effects during the arcs presence, rather than after its expiry.
earthjay.com/earthquakes/...

earthjay.com

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Prof Col Macpherson @colinmacpherson.bsky.social · 14h

Not quite what your were asking, I think, but relevant nevertheless.
doi.org/10.1144/SP35...

Crossref

Choose from multiple link options via Crossref

doi.org

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Prof Col Macpherson @colinmacpherson.bsky.social · 1d

... and found more evidence for this in the Mariana Arc. There is plenty to suggest this is an very important force influencing melt migration in many arcs. 3/3
agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Upper Plate Stress Controls the Distribution of Mariana Arc Volcanoes

Mariana Arc volcano distributions are better described as a series of great circles than as a single small circle or multiple small circles Great circle alignment of volcanoes represents tension, n...

agupubs.onlinelibrary.wiley.com

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Prof Col Macpherson @colinmacpherson.bsky.social · 1d

We speculated on this in the Sunda Arc 2/3 ...
www.sciencedirect.com/science/arti...

Linear volcanic segments in the central Sunda Arc, Indonesia, identified using Hough Transform analysis: Implications for arc lithosphere control upon volcano distribution

Hough Transform analysis is used as an objective means to constrain volcano distribution in the central Sunda Arc, Indonesia. Most volcanoes in the ar…

www.sciencedirect.com

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Prof Col Macpherson @colinmacpherson.bsky.social · 1d

Arc lithosphere tension. It's important folks. 🧪⚒️🌋 🧵1/3

Abby @abigaillily.bsky.social · 1d

The second paper from my post doc working on IODP Exp 398 is out! We show regional rifting has modulated volcanic processes at Santorini Volcano with rapid rifting resulting in a phase of highly explosive caldera forming eruptions! 🌋
Read more here:
www.sciencedirect.com/science/arti...

Tectonic modulation of caldera volcanism on the South Aegean Volcanic Arc

Many highly hazardous, caldera-forming explosive eruptions occur in extensional tectonic regimes, but the role of lithospheric rifting in modulating c…

www.sciencedirect.com

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Prof Col Macpherson @colinmacpherson.bsky.social · 2d

Gave my high school English teacher a cassette recording of Iron Maiden's song based on TRotAM and Rush's Xanadu. When returned she had clearly listened to only the first few seconds. Huge teaching opportunity missed.

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Prof Col Macpherson @colinmacpherson.bsky.social · 2d

Quartz, plagioclase, K-feldspar

Ryan Teague Beckwith @ryanbeckwith.bsky.social · 3d

Editor in chief, city editor, features editor

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Prof Col Macpherson @colinmacpherson.bsky.social · 3d

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. 🧪⚒️🌋

Callan Bentley @callanbentley.bsky.social · 3d

Cool frog.
The rock is not porphyritic though; It's amygdular (amygdaloidal).

The distinction: porphyritic texture involves big crystals surrounded by a mass of much smaller crystals. Amygdules are mineralized volcanic gas bubbles: fossil volcano burps.

Both can manifest as a polka dot pattern.
⚒️

Nina Willburger @drnwillburger.bsky.social · 4d

A marvellous #Egyptian #frog amulet, made of porphyry (height 1.2 cm).
Because of their numerous offspring, #frogs were considered a symbol of fertility.

Dating ca. 1295–1185 BC, New Kingdom.

📷Metropolitan Museum

🏺 AncientEgyptBluesky

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Prof Col Macpherson @colinmacpherson.bsky.social · 6d

Well that’s just marvellous

Take away coffee cup with bird droppings on lid

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Prof Col Macpherson @colinmacpherson.bsky.social · 6d

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.

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Prof Col Macpherson @colinmacpherson.bsky.social · 6d

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.

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Prof Col Macpherson @colinmacpherson.bsky.social · 6d

Here is a fairly old review of characteristics:

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

www.researchgate.net

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Prof Col Macpherson @colinmacpherson.bsky.social · 7d

Oh Jay, have I got a book for you …

Cover of Use of Weapons, by Iain M. Banks

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Prof Col Macpherson @colinmacpherson.bsky.social · 7d

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

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Prof Col Macpherson @colinmacpherson.bsky.social · 7d

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
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Prof Col Macpherson @colinmacpherson.bsky.social · 7d

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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Reposted by Prof Col Macpherson

Scripps Institution of Oceanography @scrippsocean.bsky.social · 7d

🌍 We're accepting applications for institution-wide #PostdoctoralScholar positions! Our research encompasses physical, chemical, biological, geological, and geophysical studies of the oceans, earth, and atmosphere.

⚠️ Learn more and apply by 10/9: https://apol-recruit.ucsd.edu/JPF04348

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Prof Col Macpherson @colinmacpherson.bsky.social · 7d

Oh buoy!

Acid Rain @bearysweet.bsky.social · 7d

UK English and American English - The pronunciation game.

👌

#language #english #pronunciation #samebutdifferent

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Prof Col Macpherson @colinmacpherson.bsky.social · 7d

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 🧪⚒️

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.

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Prof Col Macpherson @colinmacpherson.bsky.social · 7d

"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...

Triggering of the largest Deccan eruptions by the Chicxulub impact | GSA Bulletin | GeoScienceWorld

Abstract. New constraints on the timing of the Cretaceous-Paleogene mass extinction and the Chicxulub impact, together with a particularly voluminous and

doi.org

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