Tuesday, November 20, 2007
A 1000 meters below the sea floor on the night shift!
Last night the night shift at the drill site reached 1000 meters below sea floor, our target depth. We, the core loggers in McMurdo are also on night shift and we celebrated a little bit with them. It is quite hard work, from 10 pm until 10 am every night, 12 hours a day, 7 days a week, but now with the celebrations of the project and the end in sight we are getting new energy. Last night was amazing because we logged meters and meters of core without any evidence for large ice sheets at all. There were a few rocks (clasts) that probably fell out of icebergs, but really only few. That was quite unexpected, but I like surprises better than getting what is predicted: it is the exploring that makes doing this type of research so enjoyable. We also found some fossil scallops, such as these here in the photo: the original fossil is still there, but also a mold, an imprint of the shell. These discoveries make the work worthwhile and interesting. What you see here is the half core: so the drill bit drilled partially through the scallop and then the drill core was split in half.Drilling at the drillsite has stopped and now a new team will step into action. After the drillstring has been removed from the hole, the down-hole logging team will bring their tools to the bottom of the hole and then pull them up slowly. While the tools are pulled up, they will measure the physical properties of the layers of rock and also take images of the walls of the borehole. In the mean time we will continue to describe the core until we have gone through all 1011 meters of it. There will be another phase of drilling with a narrower drillbit after the down-hole logging is completed, but we will describe that core on the dayshift towards the end of the season. The plan is that we will also take a helo trip to the Transantarctic Mountains to survey the geology there, because many of the sediments in the core are eroded by glaciers from that region. Stay tuned for a report of that trip.
Posted by Sandra Passchier at 12:06 PM