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J.-A. Olive @jaodynamics.bsky.social · May 19

🎓 #PhD opportunity in Paris! Join us at @geosciences.bsky.social to study how magma reservoirs beneath mid-ocean ridges pressurize and trigger eruptions. Part of the @erc.europa.eu #SeaSALT project with strong international links. Background in (geo)physics? Apply now! tinyurl.com/yupkweya

Portail Emploi CNRS - Offre d'emploi - PhD position on the dynamics of mid-ocean ridge magma reservoirs (M/F)

emploi.cnrs.fr

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Javier Escartín @jescartin.bsky.social · May 2

🧪⚒️ The New eruption @ the East Pacific Rise after a cycle of melt accumulation & seafloor uplift. Several years of follow up by Thibaut Barreyre (CNRS@GeoOcean) & coPIs will tell how these events build the oceanic crust, 1 eruption @ a time - & comeback of ecosystems

www.nytimes.com/2025/05/02/s...

Volcanic Eruption in Deep Ocean Ridge Is Witnessed by Scientists for First Time

Researchers diving in a submersible in the eastern Pacific realized that the landscape they had studied the day before had been glassed over by fresh lava.

www.nytimes.com

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Maya Wei-Haas, PhD @mayaweihaas.bsky.social · May 2

**BIG NEWS in the geology world!** For the first time, scientists spotted an active eruption along the mid-ocean ridge!!

They visited the hydrothermal vent the day before, where a vibrant ecosystem thrived in the sweltering water. The next day, everything was gone. ⚒️🧪

My latest for @nytimes.com

Volcanic Eruption in Deep Ocean Ridge Is Witnessed by Scientists for First Time (Gift Article)

Researchers diving in a submersible in the eastern Pacific realized that the landscape they had studied the day before had been glassed over by fresh lava.

www.nytimes.com

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La Science, CQFD @sciencecqfd.bsky.social · Apr 2

[RDV 16h !] A la fin du XXe siècle, les travaux de l’océanographe Marie Tharp ont bouleversé la géologie et notre connaissance de la tectonique des plaques. Quelles furent ces découvertes et leurs impacts ? tinyurl.com/26xwkx4y avec @jescartin.bsky.social, Cécile Prigent et Laurent Jolivet

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Feb 1

If it all goes well, our now-complete observatory will be the first to document seafloor spreading and transform faulting events with geodesy, hydro-acoustics, and seismology! 🤞

Schematic illustration of the OHA-GEODAMS seafloor observatory. Credit: J.-A. Olive (LG-ENS) & J.-Y. Royer (Geo-Ocean)

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Feb 1

Last, but not least, we also recovered and re-deployed an A-0-A pressure sensor, right in the middle of the ridge's axial valley. This state-of-the-art instrument corrects its own drift by regularly re-calibrating itself against an inner chamber where the pressure is known.

An A-0-A pressure sensor, encased in a frame attached to four buoys floating on the ocean surface, waiting to be picked up. Credit: J.-A. Olive, LG-ENS / FOF

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J.-A. Olive @jaodynamics.bsky.social · Jan 31

watching the seafloor spread

The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 31

The core of the OHA-GEODAMS project is to measure active deformation for 3 years on the Southeast Indian Ridge and the Amsterdam transform fault. To this end, in February 2024, we deployed 15 acoustic beacons that have been pinging each other every few hours ever since.

2 iXblue/Exail Canopus acoustic transponders encased in yellow floats, atop 2-m tall metal tripods, waiting to be deployed on the back deck of R/V Marion Dufresne during the 2024 GEODAMS cruise. Credit: J.-A. Olive, LG-ENS / FOF

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 30

We also recovered and redeployed five hydrophones that were first deployed last year during the #GEODAMS 2024 cruise.

a hydrophone encased in an orange float just surfaced right in front of the R/V Marion Dufresne, on a calm sea. Credit: J.-A. Olive, LG-ENS / FOF

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 30

For the last ~10 days, we've been hard at work on and around the Southeast Indian Ridge at 37ºS to recover and redeploy a bunch of geophysical instruments. Let's break it down 👇

Regional map of the Southeast Indian Ridge near Amsterdam Island

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J.-A. Olive @jaodynamics.bsky.social · Jan 29

and… welcome back!

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J.-A. Olive @jaodynamics.bsky.social · Jan 28

4-8 watch best watch

sunrise on the Indian ocean seen from the starboard side of R/V Marion Dufresne

sunset on the Indian ocean seen from the back deck of R/V Marion Dufresne

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Javier Escartín @jescartin.bsky.social · Jan 16

⚒️🧪🌊 25/25 -The #VG2024 leader completed the race after 64j19h22 at 17.8 knots. More than 26700 nm (~51000 km) crossing 4 major mid-ocean ridges (Mid-Atlantic, Southwest, South East & East Pacific Rise) & around Antarctica. Thnks to @jie-chen.bsky.social for the Spilhaus map: doi.org/10.1038/s415...

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J.-A. Olive @jaodynamics.bsky.social · Jan 20

off you go, Glidy! come back with lots of 🐋 sounds

workboat deploying a glider in the open ocean

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 20

A few days ago, we deployed a Sea Explorer glider developed by ALSEAMAR and owned by ENSTA Bretagne at the location of our first hydrophone, southeast of Amsterdam island.

Julie & Jean-Arthur bringing the glider to the workboat for deployment. Credit: E. Klein

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 19

As we make our way to our study area, we map the seafloor under the ship! 🌊 Our multibeam echosounder sends acoustic waves to the ocean floor and records how much time they take to bounce back.

Data coming live from the ship's multibeam echosounder

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 14

A tradition aboard the Marion Dufresne is to stamp letters to be mailed from the French Southern and Antarctic Lands. The ship captain, chief mechanic, doctor... each have their own stamp, and the science teams make new, custom ones every year!

@jbeesau.bsky.social carefully applying an official Marion Dufresne stamp on the mail. Credit: C. Dimier

the official OHA-GEODAMS 2025 stamp: an illustration of our seismo-geodetic network across the mid-ocean ridge + the glider listening to whale sounds. Credit: J.-Y. Royer

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Javier Escartín @jescartin.bsky.social · Jan 12

⚒️🧪🌊 24/n - & the #VG2024 lead is near King's Trough, a failed rift formed perpendicular to the ridge axis 40 to 25 Myrs ago, now fossilised. First named by Laughton in '65 and described in detail by Matthews et al. in '69, the rift is a few km deep, and reaches 6000 m bsl @ Keep Deep to the East.

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 13

We're back in business after a rough storm west of Kerguelen! We're now sheltered from the waves (but not the wind!) in the Gulf of Morbihan, enjoying our first views of the island and prepping the logistics of next week's deployments.

big wave crashing against the prow of R/V Marion Dufresne. Credit: S. Furst

barometer highlighting the low-pressure zone (965 hPa) we just went through. Credit: S. Furst

Kerguelen island in the distance. Credit: J.-A. Olive

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Javier Escartín @jescartin.bsky.social · Jan 12

⚒️🧪🌊 23/n - The #VG2024 sailed over Great Meteor Guyot - part of a set of hotspot seamounts formed 20 to Myrs ago, possibly linked to the Azores hotspot to the N. The Guyot is flat topped due to wave erosion & later subsidence. It was 1st mapped & named during the N Atlantic Meteor cruise in 1937.

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J.-A. Olive @jaodynamics.bsky.social · Jan 10

i mean, the storm was bad, but not rise-of-skywalker bad

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J.-A. Olive @jaodynamics.bsky.social · Jan 10

our regularly scheduled @geodams.bsky.social programming will resume when the ship returns to a more horizontal position

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 5

Meet the #GEODAMS 2025 team! ⚒️ @earth-science.bsky.social Right to left, back to front 👇

Group picture of the GEODAMS 2025 team, on the deck of R/V Marion Dufresne, in front of Crozet Island

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J.-A. Olive @jaodynamics.bsky.social · Jan 5

but none can beat Björk youtu.be/-WnzRqCK6Fs?...

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The OHA-GEODAMS Seafloor Observatory @geodams.bsky.social · Jan 5

For several days now, several species of seabirds have been making their way with us. We've seen: the great albatross, the sooty albatross, yellow-billed albatross, black-browed albatross, giant petrels, white-chinned petrels and many others whose identification is not always easy.

black-browed albatross. Credit: Julie Béesau

white-chinned petrel. Credit: Julie Béesau

yellow-billed albatross. Credit: Julie Béesau

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J.-A. Olive @jaodynamics.bsky.social · Jan 5

the perks of the Furious Fifties

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