Hugo van Schrojenstein Lantman

Since kyanite made it to the final of Mineral Cup, I decided to contribute. Vote kyanite!

Not only is kyanite gorgeous, it's also a key metamorphic index mineral and thus one of my favourite minerals to find. Here are a few examples I've come across.

See alt text for details

#MinCup25 #kyanite

I’m very excited that #tugtupite made it to the finals but can it do this? Folded #kyanite in a high-pressure quartzite, western Türkiye. #MinCup25

A single crystal of blue kyanite. This crystal contains kinks, visible as lines within the crystal, and are the result of deformation. Some white quartz matrix is visible in the background.

Two blades of blue kyanite in a garnet-phengite-quartz rock. The phengite is visible as silvery shimmering patches, the graphite is greyish, and the few garnet are small red-brown roundish crystals mostly in the left of the specimen.

A blue-white kyanite-quartz lens in an outcrop of gray graphitic schist. A camera case in the bottom of the image provides a rough scale.

Close-up of a white-gray schist outcrop containing abundant garnet (orange circular crystals), a few blue kyanite crystals, and plenty of white quartz and silvery mica. The metal spike in the left of the image is the tip of a rock hammer.

Some bonus #kyanite pictures #MinCup25

Since kyanite made it to the final of Mineral Cup, I decided to contribute. Vote kyanite!

Not only is kyanite gorgeous, it's also a key metamorphic index mineral and thus one of my favourite minerals to find. Here are a few examples I've come across.

See alt text for details

#MinCup25 #kyanite

Thin Section Thursday!
A fractured olivine (~3 mm) in basalt. It shows undulatory extinction suggestive of plastic deformation, implying that the grain is a xenocryst entrained from surrounding peridotites. Thanks @tectonic_city. #thinsectionthursday #olivine @tectonic_city @officialcsusbgeology

I have had relatively little to share, as of late. Hope to become more active in the future, though.

I always knew in theory that a speleothem is a sedimentary rock, but I've never seen a cross-bedded stalactite before 😂

🚨 Thu 17 July: webinar at 12 noon CEST! 🚨Join Lotta Ternieten for her journey to groundbreaking findings on the early transformation of iron released from hydrothermal vents at the Mid-Atlantic Ridge. 🌊⚙️
👉 Register and find out how we can help you! — events.teams.microsoft.com/event/893d39...

Really happy with this paper with my buddies Tom & Carl. Started with online discussions during Covid lockdowns and is now published in Tectonics:

"Lithospheric Unzipping Explaining Hot Orogenesis During
Continental Subduction"

agupubs.onlinelibrary.wiley.com/doi/epdf/10....

Exciting news! Our new paper, "Carbonation and deformation of oceanic serpentinites in the Elba subduction channel: Evidence for fluid-rock interaction at seismogenic depth," is now #OpenAccess in Earth and Planetary Scientific Letters! ⚒️
authors.elsevier.com/sd/article/S...

Gorgeous! Is that a sheared coronitic granulite?

Our latest research is hot off the press! ⚒️

We've captured amazing footage of #Hydrogen gas moving through #Rock in real-time - think of it like making a movie of something that normally happens deep underground where no one can see it.

Article link: doi.org/10.1016/j.jc...

A three-dimenisonal graph showing a yellowish surface, representing the topography of a mineral grain. In the center is a crater-like feature, an indent that is the result of a nanoindentation experiment. The topography map is 15 micrometers by 15 micrometers, and the topography is in the order of 10s to ~100 nanometers.

Bit of an unusual #ThinSectionThursday
Over the past weeks, I've been busy collecting data with the Triboindenter, performing deformation experiments on grains in thin sections. See below a topography 3D model of one of these indents (looks like a crater), also collected with the indenter.

Amidst all terrible news, I am sad that here it is not better. Today the VU Amsterdam announced they'll cut Earth Sciences, and fire 39 staff. 130 students are left to figure out how to finish, and an unknown number of PhDs lose their supervisors. My heart goes out to my colleagues 😳😥

Europa heeft geologen en milieuwetenschappers nodig, terwijl Nederland juist daarin snijdt. Op dit moment wordt 3% van de 'Critical Raw Materials' die Europa nodig heeft, hier gewonnen. De EU wil dat in de komende vijf jaar verdrievoudigen, en wel volgens Europese standaarden. Dat vergt kennis 1/n

Brilliant, congratulations!

The Northeast of Corsica is part of the Alpine orogeny, and is similar to the "Schistes Lustres" of the Alps. There's a lot of blueschist and eclogite facies rocks there, including peridotite. Let me know if you'd like some literature.

Check out Stephen (et al.)'s latest paper!

A black Outer Hebrides dyke cuts across the pre-existing foliation in grey Archaean Lewisian gneiss. Thin apophysis (offshoot) and the hinge zone of the folded dyke exhibit near perpendicular angular discordance to the foliation. These rocks were folded during Laxfordian deformation and strong flattening in the limbs of the folds brought the contact of the dyke and the foliation into concordance. This outcrop is located west of the village of Rhenigidale, Isle of Harris, Outer Hebrides.

A beautiful example of an Outer Hebrides dyke cutting the foliation in Archaean #Lewisian gneiss. Although folded by later Laxfordian deformation both the dyke and a thin apophysis exhibit near perpendicular angular discordance in the fold hinge, becoming concordant in the limbs.
Isle of Harris. ⚒️🧪

Same here from the Netherlands last night

Tall grey cliffs being battered by a rough sea. Older grey Lewisian gneisses and black amphibolites are intruded by salmon-pink granitic pegmatites and aplites of Late-Laxfordian age. The cliffs are located near the Mangersta bothy on the west coast of the Isle of Lewis, Scotland.

My OH is a keen walker and getting quite good at photographing interesting geological locations. This has gone to the top of my Spring excursion list.

Pink #Laxfordian granitic intrusions invading #Lewisian gneisses and amphibolites.

Mangersta, #IsleofLewis ⚒️🧪

I am reaching out to the #geoscience community - I need help.

My MSc thesis was curtailed due to being unable to even access the building @ my previous university♿️ they provided no alternative.

They’ve taken no responsibility for this #discrimination after I submitted an appeal.

Pyroxene with exsolution lamellae in a gabbro from Susa, Yamaguchi, Japan.

A grayscale image taken with the backscattered electron detector of a scanning electron microscope. The image consists of various blobs of dark and bright grays with occasionally lines and dots throughout the blobs. Each brightness level corresponds to a mineral, in this case Fe-Ti-oxides and garnet. On the left-hand side is a large bright grain of Ti-magnetite with irregular lines of intermediate gray, Mn-ilmenite. On the right-hand side is a darker gray grain with white speckles and a few straight white lines, this is a grain of rutile with ilmenite inside.

A zoomed-out version of the previous image; there is more dark grey (garnet) surrounding the Fe-Ti-oxides

Also metamorphic rocks can have really cool Fe-Ti oxides! I found this cluster with intergrowths of Ti-magnetite and Mn-ilmenite (white & grey lines resp.), and rutile with non-Mn-ilmenite exsolution (grey & white lines resp.), in garnetite from Lago di Cignana.

A grayscale image taken with the backscattered electron detector of a scanning electron microscope. The image consists of various blobs of dark and bright grays with occasionally lines and dots throughout the blobs. Each brightness level corresponds to a mineral, in this case Fe-Ti-oxides and garnet. On the left-hand side is a large bright grain of Ti-magnetite with irregular lines of intermediate gray, Mn-ilmenite. On the right-hand side is a darker gray grain with white speckles and a few straight white lines, this is a grain of rutile with ilmenite inside.

A zoomed-out version of the previous image; there is more dark grey (garnet) surrounding the Fe-Ti-oxides

Also metamorphic rocks can have really cool Fe-Ti oxides! I found this cluster with intergrowths of Ti-magnetite and Mn-ilmenite (white & grey lines resp.), and rutile with non-Mn-ilmenite exsolution (grey & white lines resp.), in garnetite from Lago di Cignana.

Watch these snowflake-like dendritic clinopyroxenes twinkle as this thin section is rotated in cross-polarised light!❄️☃️ This is a rare volcanic rock called komatiite, from Gorgona. Credit: Charlie Gordon. #ThinSectionTuesday #Petrology #Mineralogy

Yeah you got quite lucky then! Very nice

Stunning!

Fascinating stuff! I still feel like pressure solution is underrated in metamorphic systems so it's nice to see more work about it.

Ah yeah that'll explain it! I'm sure we'll cross paths soon enough.