8 weeks 20 min
Submitted by Peter Clift on Tue, 03/25/2014 - 20:54
Today was a classic one for ocean drilling science. At this site we had used geophysics to determine that there would be igneous or some other hard rock close below the seafloor, mantled perhaps by 10 or 20 m of soft recent sediment. The proof of the pudding is in the eating, or the drilling in this case and while we were correct that the top 20 m was pretty soft the promised igneous rock failed to show at 20 m depth. Now it is the late evening and we have cored 140 m into the seafloor with only sediments and sedimentary rocks coming up in the cores so far. Surprised? You bet we have been. Where is the basement? Down there somewhere but how deep is beyond us at the moment. We continue to drill and see what the next cores bring. The geophysics is a bit non-committal at this point and we are rather flying blind. Are we disappointed? I guess some people might be but others are happy and in many ways this shows why ocean drilling is so important. Without testing and sampling rocks in the way that we do then many of our assumptions about the ocean’s structure and development simply can’t be explored or improved. Every core tells us something new about South China Sea that we did not even think about yesterday. Now the sea state has improved our drilling is being pretty effective at bringing nice samples back to our labs, so the question is whether the sediments will run out before the drilling time does, or vice versa.