6 weeks 4 days
Rock On! Basalt-A-Thon!
Submitted by Dena Rosenberger on Fri, 12/07/2012 - 22:56
Blocks of basalt present a library of the history of the ocean floor.
Where are we now?
Off the western coast of Costa Rica, in the Pacific Ocean, Hole U1414A. Our coordinates: 8°30.2’ North, 84°13.5’ West. Water depth is 2460 meters (over a mile and a half!). Gorgeous morning with a bit of rain and the Costa Rica coastline in the distance!
Scientists at Work
We are all the way down past 400 meters below sea floor (mbsf)! Since the rock is very hard and takes some time, they are bringing up half cores at a time.
Lot’s of talk around the sampling table, but until thin sections can be prepared and more chemistry is done, these are just ponderings at this point!
Preliminary guesses are that they consist of mostly medium dark to dark basalts with quartz layers and imbedded with grains of pyrite. Some lighter basalts.
Intermittent cracks could be filled with calcite, although tests haven’t as yet determined what these light-colored cracks contain.
Some of the scientists think that some of the darker gray-green “spots” are possibly olivines or pyroxenes. Olivine is a magnesium iron silicate, and pyroxene is also a silicate made of some combination of calcium, sodium, magnesium, iron, or aluminum.
These minerals may have filled in the “vesicles,” which are the vacancies left by bubbles of gas when the rock was molten.
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?
We had our last safety drill today! They always tell us days in advance, so that we know it is coming. At the designated time, Captain Skinner announces over the loud speakers around the ship: “Attention, attention. All personnel. This is a drill. This is a life boat drill.” So, you have to grab your life vest, helmet, and safety goggles then quickly go to your assigned life boat and check in with the officer there. I took the main stairwell...and so did everyone else!
We were shown how to use a device that shoots out a 250 foot long rope in case you need to try to link up with a large vessel from the life boats. He cautioned us that it has a “kick,” so brace yourself so it doesn’t knock you over. I was hoping he would show us, but I guess it is a one shot deal so they didn’t want to waste it. He also told us not to shoot it at a helicopter!
For more photos, see our Facebook page!
From the Hard Rock Café on Cocos Avenue!