ins.: 2015-08-09 00:00; ( Age: 9 yrs )
This past week, the science team and drill crew extracted ...
This past week, the science team and drill crew extracted sediment cores from Holes B, C, and D at Drill Site #1, starting with Hole E as per August 8th. The reason multiple holes are drilled at approximately the same location is to increase the total sediment recovery. To further elaborate: Suppose we had a hole that was 100 meters deep. In the ideal world, we would be able to recover all 100 meters of sediment with no breaks or missing sections. However, in all scientific coring operations, sediment is retrieved in successive meter-scale intervals of core (in our case, it is 3 meters). Because of this, sometimes we only retrieve 85-90 meters of sediment from a 100 meter hole (85-90% recovery), due to problems like sediment falling out the bottom of the core in the hole before we can get our hands on it on the barge. To compensate for our problem of missing portions in our sediment core record, we drill multiple holes at each site so that material that is not present in one hole is represented in another. In this photograph, a driller is pulling out the HPC (hydraulic piston core) after a successful drive into the lake sediment. At the bottom of HPC is our precious record of past climate change! Photo: Kristina Brady Post: Christine Y. Chen