The Mystery of the Exploding Cores – Day 31, 8/4/2009
Why do some cores explode? One of the problems we’ve had on this expedition is that some of the cores are a bit gaseous. As you go to the sea floor and below it, the pressure from the water above is tremendous. Styrofoam coffee cups dropped to the sea floor come back a fraction of their original size. Why is that?
Well, the reason is the pressure forces the gases to decrease in volume, and Styrofoam cups are full of pockets of air. That same air insulates your coffee from the air in the room, and keeps it warm longer.
So that’s why the cores explode. To combat this, the technicians drill holes in the core liners (the plastic sleeves the cores are recovered in) to release the pressure. They try to minimize disturbing the core, but leaving the gases to build up volume can be explosive.
An amusing byproduct of the holes are the "worms" of sediment that escape. As with any sample, these are collected, documented and saved.