#xenoliths
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mapperwocky.bsky.social
Lots of modeling in those composition determinations to, yeah? Somewhat educated guess and extrapolations from random mantle xenoliths recovered combined with experiments and seismic returns, is how I understand it.
December 6, 2025 at 5:12 PM
nadwgab.bsky.social
308 of #365Minerals 🧪⚒️

Diopside:
- Pyroxene mineral
- Forms in ultramafic igneous rocks, xenoliths & metamorphic rocks
- Can turn into chrysotile when hydrothermally altered
- Name comes from the Greek "dis" (twice) & "òpsè" (face) because its vertical prism can be orientated in two ways #minerals
Pale green diopside prisms with cherry red hessonite crystals. Some of the diopside crystal faces are annotated with crystal face numbers. From Ala, Italy. Specimen on display in the Natural History Museum, London. A chunk of rock with pale green diopside crystals filling its cavity, There's also white, anhedral diopside and some pale brown grossular crystals. From Ala, Italy. Specimen on display in the Natural History Museum, London. A rough pale green and opaque diopside crystal which is slight flattened. It contains some inclusions of brown phlogopite (two patches) and apatite. Label text: Flattened prism with phlogopite. From Perkins, Quebec, Canada. Specimen on display in the Natural History Museum, London. Three translucent diopside gemstones. Left: A rectangular step-cut, pale brownish-green and from an unknown locality. Top right: An oval mixed-cut, green and from Madagascar. Bottom right: A rectangular cut whose colour varies from colourless to green, from an unknown locality. Specimens on display in the Natural History Museum, London.
November 4, 2025 at 11:07 AM
callanbentley.bsky.social
A couple of xenoliths in the Campus Andesite (a.k.a. Muleros Andesite, 47 Ma) @ Cristo Rey laccolith. ⚒️
Two fingers next to an outcrop of very porphyritic andesite containing an angular dark inclusion. A hand next to an outcrop of very porphyritic andesite containing a cobble sized inclusion of granodiorite.
October 17, 2025 at 4:06 PM
pennywieser.bsky.social
Excited to share my new open-access paper looking at magma storage depths for these beautiful xenoliths from Mauna Loa Volcano. doi.org/10.1007/s004... 🧵below, TLDR - previous suggestions of ~20 km deep Opx crystallization are inconstant with fluid inclusion depths and thermodynamic modelling.
Whole thin section scans in cross polarized (XPL) and plain polarized (PPL) light. a) 48g comprises two large orthopyroxene oikocrysts; one at the top left showing brown colors close to extinction, and one at the bottom right showing creamy-white colors. b) shows the same scan in PPL. c) 48i comprises a single orthopyroxene oikocryst at extinction. In contrast, olivines show a variety of interference colors. d) Same scan in PPL. e) 79a comprises one major orthopyroxene oikocryst (brown), with two smaller oikocrysts attached (blue). The two insets compare the rounded nature of the olivines inside the xenolith with the more euhedral shapes of those on the outside. These defined crystal faces may have formed during renewed growth in the carrier melt during transport or may have avoided the dissolution reaction. f) in PPL, cleavage can be seen showing a constant direction across large regions of the xenolith.
September 23, 2025 at 2:59 PM
gernon.bsky.social
There are some great spinel-harzburgite xenoliths to be found in some historic basaltic lavas in Lanzarote
April 23, 2024 at 6:07 PM
geologyjohnson.bsky.social
They have some nice rocks. See if they can get you some basalt with mantle xenoliths.
June 24, 2024 at 6:59 AM
timdemko.xyz
Field work in the White Tank Mountains in central Arizona USA: great igneous relationships between screens or xenoliths of Proterozoic schist and a Cretaceous/Paleogene granite! There are also some younger pegmatite veins that cut both. This is also the lower plate of a metamorphic core complex.
Photo of an outcrop of light brownish red schist cut by lighter granitic dikes. Shadow of the photographer for scale in the lower left corner. Photo of an outcrop of screen or large xenolith of light brownish red schist surrounded by a lighter granite and cut by lighter granitic dikes. Photo of an outcrop of a light colored granitic dike cutting a darker gray schist. The foliation of the schist is vertical and cut at a right angle by the dike. The dike has two bands, an equigranular granite and coarsely crystalline pegmatite. There is a brass pen for scale.
December 7, 2024 at 5:12 AM
blastylavagrrrl.bsky.social
Gorgeous! There's a lovely, thankfully protected, site of big colorful xenoliths on that side of the Big Island. I've never been in a sadder/happier van full of geo majors. Sad we couldn't take rocks, happy we saw them, and happy knowing the place wasn't picked clean.
June 11, 2024 at 1:07 AM
pennywieser.bsky.social
Berenise Rangel investigated the exact xenoliths analysed by Gaffney for her honours project (48g, 79a, 48i, 66d) using fluid inclusion barometry. I was actually pretty convinced she would find high pressures, but she didnt...In fact, her depths were very similar to my pressures obtained from tephra
Figure showing a violin plot of fluid inclusion pressures. Depths are mostly 2-6 km, with nothing anywhere near close to the 20 km suggested by Gaffney (2002). The distribution of FI from extrusives and xenoliths overlap very well, and xenoliths also overlap very well with the magma that carried them to the surface.
September 23, 2025 at 3:05 PM
johniac.bsky.social
SciTech Chronicles. . . . . . . . .Mar 26th, 2025

bit.ly/stc032625

#xenoliths #volatiles #subduction #models #spike #glycans #receptor #low-mutation ##Yellowknife #linear #dodecane #SAM #lipids #Mesoscale #signature #transport #photolysis #replenishment #size #thickness
SciTech Chronicles. . . . . . . . .Mar 26th, 2025
Strategy tells culture where to go. Culture tells strategy what's acceptable. Vol II No 77 535 links Curated The Deep Frontier of Mantle Mag...
bit.ly
March 26, 2025 at 3:57 PM
edmarshall.bsky.social
@vaccinium-sultan.bsky.social is always posting awesome xenoliths. They aren't folds or thin sections, but they are rocks!
July 25, 2025 at 10:46 AM
vaccinium-sultan.bsky.social
Back on Oʻahu and Big Island in late January and super excited to get to (re)visit mantle and crustal xenoliths of the Koʻolau Honolulu Volcanics as well as those of Hualālai, Mauna Kea, and unusual Mauna Loa ultramafic mantle xenoliths hosted by tholeiitic basalt.

#xenolith #peridotite #geology
November 21, 2025 at 3:34 AM
grantgoodman.bsky.social
I honestly don’t remember that story. I’ll have to dig up my old Xenoliths.
November 26, 2025 at 2:36 PM
spahn711.bsky.social
Unearthing peridotite xenoliths! 🟢

Here I am holding parts of the Earth's upper mantle that were brought to the surface in a volcanic eruption! So grateful for the rare opportunity to pull these from the Earth myself, where the earth sparkles green!
November 12, 2024 at 10:11 PM
vaccinium-sultan.bsky.social
Pyroxenite xenoliths of #mantle origin were erupted from only 3 Hawaiʻi rejuvenation vents, composite #peridotite - #pyroxenite xenoliths are rarer and may reflect opx dissolution. Revisiting this Oʻahu sample from January, no visible garnet in handsample but cool nonetheless.

#geology #geoscience
May 19, 2025 at 1:18 AM
vaccinium-sultan.bsky.social
Garnet Pyroxenite Mantle Xenoliths hosted in melilite nephelinite tuff
Āliamanu-Moanalua vents, Honolulu Volcanics, Koʻolau, Oʻahu, Hawaiʻi

#geoscience #geology #volcanology #volcano #xenolith #garnet #pyroxenite #mantle #garnetpyroxenite #tuff #HonoluluVolcanics #Hawaiʻi
July 10, 2025 at 3:49 PM
drsadhbh.bsky.social
First blow of the hammer on the basalt dike yielded what I'd hoped to find - mantle xenoliths, mostly olivine, for which the dike is famous (in its field). Very exciting! Second photo is close up of xenolith - phone photo taken through hand lens.
November 13, 2024 at 8:15 AM
grum61.bsky.social
2/2 On the west coast of #Easdale complex multiple dykes intrude into the #slate country rock, and into each other! #xenoliths highlight the #dykes being younger than the slates #lawofincludedfragments
April 10, 2025 at 4:53 PM
vaccinium-sultan.bsky.social
Gorgeous spinel peridotite mantle xenolith hosted in melilite nephelinite tuff. Xenoliths from these vents encompass all the metamorphic textures.
Moanalua vent, Honolulu Volcanics, Koʻolau, Oʻahu, Hawaiʻi

#geoscience #geology #volcanology #volcano #mantle #xenolith #spinel #peridotite #Hawaii
July 10, 2025 at 3:55 PM
drsadhbh.bsky.social
Thought I'd post a picture of a thin section of rock that I was very excited to collect a sample of over the summer - mantle xenoliths in a basalt dike from Donegal in NW Ireland. I was NOT expecting such fresh olivines! ⚒️
Olivine crystals showing as bright green between crossed polars, at the edge of a mantle xenoltih from a basalt dike in Donegal, Ireland
November 23, 2023 at 1:24 PM
karabrug.bsky.social
Mantle xenoliths (green) in basanite lava (black) at San Carlos, 2014
Photo of green and black spotted boulders.
August 30, 2023 at 10:35 PM
vaccinium-sultan.bsky.social
Cumulate #ultramafic #xenoliths ( #dunite & #spinel ± #plagioclase #peridotite) of the #Hualālai Volcanics with @volcanoesinthesea.bsky.social
January 29, 2025 at 11:28 PM
yblissp.bsky.social
When my professor spoke about xenobombs I did not imagine xenoliths expeled by volcanoes and therefore having a basalt layer around it
I thought we be picking up a blaster or something 😔
February 9, 2025 at 2:28 AM
vickyveritas.bsky.social
So cute! Cool xenoliths, too!
September 8, 2024 at 9:41 PM
pennywieser.bsky.social
So in summary, we trust fluid inclusions more than thermodynamics given the lack of experimental constraints at these P-T-X conditions. However, thermo also isnt inconsistent with our suggestion these xenoliths came from 2-6 km rather than super deep depths.
September 23, 2025 at 3:11 PM