Rocks, rocks and more rocks

Visual Core Description, also known as VCD, involves recording the composition and type of rock that has been cored, as well as the relationships between the types of material in the core. It is an important, exciting, and often frustrating job:

The rate at which core arrives on deck can be quite variable. If we are coring continuously we can get a 3 m core every hour and a half. However, if pipe is tripped to change the bit or case the hole, an entire shift can pass by with only a single core to keep us occupied. Shifts tend to be either very busy, or very quiet.

When the core arrives on deck, all everyone wants to do is to look at what has come up, including me. Nonetheless, the core has to be measured and curated before I’m supposed to look at it. Usually it takes around 30 minutes for the core to make it from the deck to the desk in my “office” (by which I mean a shipping container).

When chips of rock break loose from the core catcher, I have a very small sample to look at under the microscope. Otherwise the entire core is wrapped in 5 mm of (not very) see-through acrylic plastic. It is our job (mine and, on the night shift, Michael’s) to do a preliminary description so we know what to expect when we split the cores in Bremen in autumn. This isn’t the easiest of tasks as we cannot physically touch the cores and the core liner is often fogged up or masked by drilling mud!

Once I’ve completed my description, the core moves on to the petrophysicists and then into a refrigerator for storage until it gets opened up for re-description by the entire science party in 5 months’ time. In the mean time, the VCD made onboard is an important guide to help the rest of the science party make sample requests from the core. We have already made many interesting and exciting observations; we only have to wait 5 months to test any of them!

Auriol Rae – Petrologist

Featured Image: ELeBer@ECORD_IODP


5 thoughts on “Rocks, rocks and more rocks

  1. Sounds like you are having an interesting time Audie. It’s Sunday and l am at Sway with Granny and we have just seen your article. Enjoy the rest of your days there. Love. Dad


    1. Hullo Auriol, Sounds seriously impressive – and good to read about your activities. More of this please…..




  2. All looks seriously impressive – and glad we’ve got something to read on your expedition. More of this needed please.



  3. Hi Auriol from Edinburgh! Carla managed to display this page so we have caught up with you! All sounds fascinating, looking forward to the next instalment. We send our love, what’s the food like on board? Valerie and Carla!


  4. Welcome home Auriel!
    I’m only catching up with the blog now- and here you are back again.

    But it doesn’t mean we haven’t thought about you regularly and spoken about you and your project to others.
    Hope you recover well and enjoy a break now
    A Gwen


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