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Edward W. Marshall

@edmarshall

πŸŒ‹ Geochemistry Postdoc at FAU Erlangen-NΓΌrnberg in πŸ‡©πŸ‡ͺ. Studies Icelandic volcanism, magmas, and the mysteries of Earth's mantle.

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21.09.2023
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Latest posts by Edward W. Marshall @edmarshall

I don't wanna sound too critical here. Its a super cool study. Ive never heard of this kind of iterative method before. But in places the paper seems to dismiss the relevance of any other lithologies in incipient melting. Im not so convinced that CO2 in the mantle only resides in fertile peridotite.

26.02.2026 21:50 πŸ‘ 1 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

If I understand correctly, they basically identify the composition of incipient melt of a very volatile enriched KLB-1 to be kimberlitic. So, what happens if they use other peridotite/pyroxenite compositions? Or what happens if the system isnt very enriched in volatiles?

26.02.2026 21:39 πŸ‘ 2 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

Hiring a new professor in my department who specializes in Earth surface topics (e.g. climate, sediments, soils, oceans, etc). Non-germans welcome to apply-- the postdoctoral qualifications (e.g. habilitation) are just for German applicants.

14.01.2026 16:36 πŸ‘ 1 πŸ” 3 πŸ’¬ 0 πŸ“Œ 0
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Geochemistry and ore deposits The working group Geochemistry and ore deposits focuses on the fundamentals of element enrichment and depletion upon fluid transport and fluid-rock interaction in the Earth’s crust.

Come and measure your samples with our LA triple quadrupole ICP-MS!
Our analyses:
-trace elements in a wide range of geomaterials
-S isotopes in sulfides
-element mapping
-U/Pb geochronology (coming soon!)
-and more...
www.gzn.nat.fau.eu/geochemistry-and-ore-deposits-2/la-icp-ms-laboratory/

28.11.2025 09:17 πŸ‘ 1 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

Job alert: #postdoc in experimental Petrology/ Geochemistry, University of Innsbruck (AT). Apply by 11 January 2026 or position open until filled. More info: buff.ly/2A7JsJN

26.11.2025 07:30 πŸ‘ 0 πŸ” 3 πŸ’¬ 0 πŸ“Œ 0
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Carbon Isotope and Abundance Systematics Reveal an Insignificant Crustal Sink of Mantle‐Derived CO2 in On‐Land Rift Zone Geothermal Systems CO2 in carbonates of the Iceland crust predominantly originates from the mantle Only 1%–10% of mantle-derived CO2 that degasses along the Iceland rift zone is permanently fixed into carbonates C...

New article just published πŸ€— Find out why the Iceland rift may provide such a significant source for mantle-derived CO2! agupubs.onlinelibrary.wiley.com/doi/10.1029/...

#geochemistry

03.10.2025 14:37 πŸ‘ 5 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
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Modeling seawater-basalt interaction at 10–100Β Β°C: Controlling parameters and effects on the composition of the oceanic crust and seawater Chemical reactions and element mobilization during seawater-basalt interaction play a central role in regulating global element fluxes between seawate…

New publication out on the interaction of seawater with oceanic crust! 🌊 πŸͺ¨ We show how temperature, reaction progress, time and crystallinity of the crust affect elemental fluxes! www.sciencedirect.com/science/arti...

27.09.2025 14:25 πŸ‘ 2 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
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Interlaboratory reproducibility of ID-TIMS U–Pb geochronology evaluated with a pre-spiked natural zircon solution Abstract. The highest precision and accuracy in U–Pb geochronology is achieved using isotope dilution thermal ionisation mass spectrometry (ID-TIMS), a technique which owes its reliability to precise ...

Happy to share the long-awaited results of our community experiment comparing high-precision ID-TIMS U-Pb lab performanceπŸ§ͺβš’οΈ
We do pretty well but as ever there is room for improvement πŸ€“ Stay tuned!

doi.org/10.5194/gchr...

04.09.2025 16:08 πŸ‘ 11 πŸ” 3 πŸ’¬ 0 πŸ“Œ 1

Oh I see! Yeah you are right-- it does make it seem like those types don't exist. I actually remember being confused about this when I was a student.

29.08.2025 16:06 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

It is? I thought it was called tachylite. I thought true obsidian was always silicic. In my head the Venn diagram would have a big circle for volcanic glass with tachylite and obsidian as non-overlapping circles within the volcanic glass circle.

29.08.2025 15:58 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

I guess they are writing to integrate the text better with rocks that students likely have in their classroom or might be familiar with prior to the class. They are putting in the ladder at the shallow end of the pool.

29.08.2025 15:34 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

I should say-- the one cartoon figure, not figures. Anyway, definitely not as depicted-- the core-mantle boundary being stretched to the surface.

13.08.2025 11:34 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

The title of the artcle and the figures of the article are misleading. The core isn't leaking out at the surface. Tiny fractions of core material are entrained into the mantle, and this core-contaminated mantle material eventually is melted beneath some hot spots.

13.08.2025 11:29 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

They are really cool!

31.07.2025 11:18 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

What are these? Are they glomercrysts weathering out of a lava?

31.07.2025 11:18 πŸ‘ 0 πŸ” 0 πŸ’¬ 2 πŸ“Œ 0

@vaccinium-sultan.bsky.social is always posting awesome xenoliths. They aren't folds or thin sections, but they are rocks!

25.07.2025 10:46 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Whoa this is really cool!

24.07.2025 04:14 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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Mush Disaggregation and Dike Propagation Timescales at Active Volcanoes: Evidence from the 2022–2023 Fagradalsfjall Eruptions Abstract. The architectures of magma plumbing systems and timescales of magmatic processes are fundamental to understanding volcanic eruption dynamics. Thi

The typeset version of the 2022-2023 Fagradalsfjall paper is out, so let’s go over the main points of the paper πŸŒ‹

18.06.2025 10:15 πŸ‘ 10 πŸ” 11 πŸ’¬ 1 πŸ“Œ 0
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Crystal mush processes and crustal magmatism Nature Reviews Earth & Environment - Crystal mush processes are key to magmatic differentiation, volcanic system behaviour and some mineral resources. This Review discusses the processes...

Interested in crystal mushes? New review paper just out: rdcu.be/eo9pC
Great to be part of the team!

05.06.2025 11:45 πŸ‘ 21 πŸ” 3 πŸ’¬ 0 πŸ“Œ 2

Amazing work by @albertocaracciolo.bsky.social . It's the coolest diffusion timescale work I've ever seen. You can see each eruption priming and how they are related to one another. Just super cool science.

03.06.2025 08:31 πŸ‘ 0 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
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Mush disaggregation and dike propagation timescales at active volcanoes – Evidence from the 2022-2023 Fagradalsfjall eruptions Abstract. The architectures of magma plumbing systems and timescales of magmatic processes are fundamental to understanding volcanic eruption dynamics. Thi

πŸš¨πŸŒ‹New paper on the geochemistry and petrology of the 2022–23 Fagradalsfjall eruptions on the Reykjanes Peninsula, Iceland. We study temporal variations in the magmatic plumbing system and link diffusion timescales to monitoring signals, tracing the timing of mush disaggregation and dike propagation

03.06.2025 08:23 πŸ‘ 14 πŸ” 4 πŸ’¬ 0 πŸ“Œ 1

Hmm tricky! I tried to think of relatively recent and/or short papers.

31.05.2025 20:27 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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A process-oriented approach to mantle geochemistry The numerous chemical and isotopic studies of oceanic basalts have shaped our perception of mantle geochemistry over the last six decades. As partial …

Oh oops www.sciencedirect.com/science/arti...

31.05.2025 20:20 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

This proposed budget is a policy statement, not an appropriation.
There are still a lot of steps and potential changes ahead before it becomes one. This is not a time to sit quietly, team. Let's go.

31.05.2025 13:38 πŸ‘ 106 πŸ” 41 πŸ’¬ 2 πŸ“Œ 0
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Magmatic filtering of mantle compositions at mid-ocean-ridge volcanoes - Nature Geoscience The Earth's mantle constitutes over 80% of the planet's volume and is a key reservoir in global geochemical cycling. An overview of the progress in understanding the generation of mid-ocean-ridge basa...

I'm not really sure what you're looking for, or even if such a paper exists, but here are some contenders that popped into my head.

www.nature.com/articles/nge...

www.nature.com/articles/nge...

www.nature.com/articles/s41...

31.05.2025 17:37 πŸ‘ 2 πŸ” 0 πŸ’¬ 2 πŸ“Œ 0

This was written about media content, but the same can be said for scientific content. When the incentive structure is based around numbers of papers and numbers of citations, it's a system that assumes quantity means quality. It's ripe for abuse by AI, which can do quantity really well...

29.05.2025 06:38 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Thanks Emily!!

27.05.2025 17:24 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Thanks! It was by far the most exciting science I've ever done! It's true that the earliest lavas are buried- maybe we should be drilling and collecting core from more lava shields! The cores from the HSDP borehole were super cool and revealing, for example.

27.05.2025 12:18 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
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The Petrology and Geochemistry of the 2021 Fagradalsfjall Eruption, Iceland: An Eruption Sourced From Multiple, Compositionally Diverse, Near‐Moho Sills We use high frequency sampling to observe rapid changes in lava composition during the 183Β day 2021 Fagradalsfjall eruption The eruption was sourced from 12 to 15Β km depth, corresponding to the l...

Cpx-melt and melt inclusion volatile saturation pressures say they come from the lower crust or near Moho! Probably syn-eruptive decompacted crystal mushes! agupubs.onlinelibrary.wiley.com/doi/full/10....

27.05.2025 07:52 πŸ‘ 4 πŸ” 0 πŸ’¬ 1 πŸ“Œ 1