Lake E Daily News, Sunday April 26th, 2009
Today we reached another important milestone for the Lake E Project by calling an end to the bedrock drilling. This decision was made jointly by all four of the PIs (three of us here and Martin Melles by phone) largely because 1) we have recovered over 200 m of the impact sequence in the past 5 days and 2) we have only 4 tons of mud left to attempt to replicate as much of the sediment section as possible from -150 m to -315m blf, where we have the most gaps. The bottom of Hole 1C was at -688.77 m (total drillers depth) or -517m blf.
Our next task will be to move the rig, en-masse, about 10 meters! This distance is necessary to avoid close proximity to the other holes 1A, 1B and 1C. The move itself should take only a few agonizing minutes but first, we have to take up all of the PQ and HQ drill pipe, store it on sleds off the ice pad to remove weight, then pull casing, break all of the welds, and remove all of the unused mud from the platform and ice pad. We will do everything possible to make the rig as light as possible, get it completely jacked up from the ice, and prepare it to be rolled over dented HQ pipe that has been cut into 30 cm lengths and placed under the runners on the platform. Everything inside the rig has to be secured to prevent any damage. Then we plan to simultaneously pull the entire rig with 2 bull dozers and push with one behind it. With any luck the entire rig will move as a single unit and we will have finished by Tuesday or Wednesday.
On the science side, Christian has been working on initial descriptions and photos of the fragmented and monomictly brecciated volcanic target rocks and suevite (polymict, melt-bearing impact breccia), which are part of the central uplift of the El’gygytgyn crater. Pictures of some of the rocks should show up on the ICDP web site very soon (under "image of the day").
Weather today was nearly perfect -- calm, blue skies and temperature about -10C, lows to about -20 C. Would be great to get another 3 weeks of this!
cheers.....Julie BG
