Agnes Pointu's blog

The Ninety East Ridge

Family portrait

We have 4 micropaleontologists on board during Expedition 362 who are working together to track the age of the core.

Meet our micropaleontology team! From left to right: Freya for Diatoms, Wen-Huang for Foraminifers, Jan for Nannofossils and Sarah for Radiolarians.

Why are we using microfossils?

How we drill and core in hard sediments and rocks

When we want to drill into hard sediments and rocks, we have to change the drill bit. In the deeper part of Site U1480, we used an RCB (Rotary Core Barel) drill bit rather than the APC/XCB we used before for coring the younger, softer sediments.*

In the mud for love

"It is good to have an end to journey toward; but it is the journey that matters, in the end".

Ursula K. Le Guin, The Left Hand of Darkness

When we see all this mud coming from beneath the seafloor, we can ask ourselves the question: "What is it made of"?

Everybody wants to be a cat

When you hear "CORE ON DECK- CORE ON DECK" (it's always twice, not once, not three times, just twice), you have to go to the catwalk.  It is a narrow, covered work area, wide enough for a lot of obese Maine coon cats however. I don't really understand that name. Maybe because I am French?

What is a subduction zone?

It's the case-ing !

Yesterday, we starded our next hole in a new way because this time, we want to drill until the sediment/basement interface (1450 mbsl)! Before that, we have to build a reentry system that includes 754 m of "casing".

What is casing?

Attack the mud!

Deep hole often requires several changes of drill bits. When you drill the bottom of the seafloor, we can use the Advanced Piston Corer (APC) which is used to recover relatively undisturbed sediments from very soft to firm sediments.

The APC is a hydraulically actuated piston corer and it allows to recover continuous 9.5 m samples.

How does it work?

Tell me who you are, I will tell you where do you come from

There is an important question to answer for the sedimentologists: where do the sediments come from?

One way to answer to this question is to take a look at the sands in the cores. It is one of the jobs of Kitty Milliken on the JR.

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