The picture above shows some of the cores which we looked at. These are all igneous rocks which were drilled from the ocean floor by research ships such as the JOIDES Resolution shown below.
But perhaps one of the most interesting cores is the one shown below which captures a slice of time right through the period where dinosaurs went extinct, which is known as the KT boundary.
This core has an iridium rich layer at the top of the green band which scientists believe formed from the asteroid impact which killed off the dinosaurs. Iridium is a rare element on Earth but it is plentiful in asteroids which is strong evidence for a meteorite impact being responsible for the extinction of the dinosaurs.
All of the cores at the repository were divided length ways into two giving a working half and an archive half. The working half could be sampled for scientists to study for research into all sorts of areas (such as palaeomagnetic analysis or microbiology). The archive half is also accessible for study but no samples or altering of this half can be done so that there is always a record kept of the cores in case other people want to study them in the future.
All of the cores were kept in a large room (shown below) which was kept at 4°C, but luckily we didn't spend that long in there and spent most of the days working in a much warmer lab next door!
On our visit we logged the mineralogy and textures, geological structures (such as faults) and metamorphic alteration to the minerals which we could see in the cores. I found this exercise very interesting and it was an exciting thought that once these rocks would have been buried deep beneath the ocean, and modern technologies now mean that we can extract rocks from the Earths interior and from beneath km's of ocean!
Reports for many drilling expeditions can be found on the International Ocean Drilling Programme (IODP) website if you use the search bar at the top. There is also more information about the core repository, events happening there and an interactive map showing where cores have been extracted from:
I strongly encourage you to follow the link above and take a look for yourself!