6 weeks 5 days
Hard Rock Café
Submitted by Dena Rosenberger on Thu, 12/06/2012 - 23:26
The sign above the sampling table is fitting for today…
Where are we now?
Off the western coast of Costa Rica, in the Pacific Ocean, Site U1414. Our newest coordinates: 8°30.2’ North, 84°13.5’ West. Back to much deeper water on the Cocos Plate.
Water depth is 2640 meters (over a mile and a half!). Rain this morning, beautiful outside now!
Scientists at Work
They have switched the drill bit to the harder rock corer, the RCB coring assembly. This takes longer because the stuff they are drilling through is harder, so they also switched to half cores. Now, on the sampling table they have to cut the core with the saw or use the drill to take out samples.
Scientist Luigi Jovane shows off his core drilling skills!
The scientists are very happy that they are seeing harder rock and also deformed rock. Deformed rock occurs where the sediment layers that we were seeing in previous cores have been subjected to heat and/or pressure and have been pressed together, pulled apart, and stressed in other ways, as well.
You can still see the layers in some places, but they have definitely been changed. They believe that these rock cores are the same light-colored calcareous ooze that we were seeing before, but stressed and pressed together into rock. There is a lot of silica in them, and the volcanic ash is still evident in dark layers.
And, they smell bad! One thought was that some bacteria that lived in the sediments combined with available iron atoms to make the mineral pyrite, which can produce a sulfur-smelling gas.
There was also evidence of something called “bioturbation.” This occurs when a living organism disturbs the sediment, and the disturbed sediment gets solidified into rock. Scientists can tell by the patterns preserved in the rock that a live organism left its mark there.
Life on Board
Spotlight On Schools (SOS):
Riverview Elementary School in the Lakeside Union School District, Lakeside, California, is dedicated to preparing students to be the global leaders of tomorrow. Their outstanding curriculum is infused with essential 21st century learning skills including world language instruction, technology, critical thinking, and creativity. They gave me a school T-shirt to take along with me to the Costa Rica Seismogenesis Zone!
In the photo, can you guess where I am standing on the ship?
Today I got to observe a “Man Overboard!” drill, which was somewhat humorous. They threw a 100 pound floating dummy off the ship, and the crew guys grabbed the Zodiak and “rescued” him.
The doctor was on hand, as well, but the patient (next to the doctor), doesn’t look so good!
For more photos, see our Facebook page!
From the Hard Rock Café on Cocos Avenue!