2 weeks 2 days
Of Kites and Cores
Submitted by Dena Rosenberger on Thu, 11/29/2012 - 23:19
Welding with a view!
Where are we now?
Off the western coast of Costa Rica, in the Pacific Ocean, Site U1413. Our coordinates: 8°44’ North, 84°7’ West. Water depth: 540 meters (~1/3 mile). We will be moving soon!
Scientists at Work
Our final cores at this site were characterized in this morning’s science update as “calcareous, greenish gray silty claystone to siltstone, with occurrences of wood, shell, and gastropod fragments…nannofossils indicate an early to middle Pleistocene age.” Sounds familiar, except, do you know what a “gastropod” is?
You can see the little shell bits in this core. All of these cores are getting more and more "lithified" which means "hard rock". The cylindrical samples have to all be drilled now, and as usual, space where the sample was taken out is replaced with a Styrofoam cylinder. You can also see tiny shiny pieces of pyrite in the core!
Where do we go from here? After much discussion amongst the lead scientists and hearing propositions from the various science groups, a decision has been made regarding our remaining time and what to do with it. We stopped drilling this afternoon at about 600 meters below sea floor (mbsf), and tonight we will start downhole logging. Downhole logging is when you lower instruments down the hole to find out information about the surrounding sediments. I think everyone is "GLAD" to be moving to the next site soon!
When we have finished this task, we will go back to the site above the decollement and drill 50 meters downslope of where we drilled before. This is a very important site for understanding the interactions of the upper plate with the lower plate, but the danger of getting the drill bit stuck at this site is high. If this happens or if we run into too many problems, we will stop drilling immediately. In the remaining time after that, we will move to another site and hopefully core into the basement rock there.
All of this may change depending on drilling conditions, but that is one of the things that makes science interesting!
Life on Board
It was a blustery, rainy, dark day, with ocean swells bigger than any we have had so far. But, the good part was…the Kite contest!
We actually had wind today, and a lot of it! So, after lunch (for me, dinner for some , breakfast for some, middle of the night for some), we held the kite flying contest. The categories included: biggest kite, smallest kite, most dangerous kite, and highest flying kite. All were constructed of materials that people found around the ship!
For more photos, see our Facebook page<!
From the subduction zone…