Archive of September 24th, 2007

Teacher at Sea log for September 24, 2007

Today I will show you the tools we use as we collect and then store the rock samples. As Jason2 collects samples they are stored in baskets (milk crates). The baskets are arranged with dividers and tape markers so that we can tell from the camera view where the rocks are being placed. Then as the baskets are unloaded we use drawings, basket maps and photographs to place the rocks in plastic bags. Each bag is labeled with the Jason 2 dive number and the sample number.
In the Kilo Moana "Wet Lab," the rocks are rinsed in fresh water. Next the rocks are sawed open so we can see a cross section of the sample. The rocks dry on top of their personal storage bag while they are further measured and described by the watch team. Finally, they are stored in 5 gallon buckets until we take them off the ship.

Science Update by Todd Bianco

We have begun our dive on the fresh flow west of Kaula. This flow, as mentioned before, is possibly 3-5 million years younger then the main shield lavas at Kaula. One estimate of the age of our samples comes from the thickness of manganese coating, which increases with time at about 2.5 mm per million years. At this time, we have more than twenty samples of what looks like fresh pillow lavas and lobate flows. Though we do see some debris flow, most of the area looks unmodified by mass wasting, especially compared to our observations south of Kauai. If the samples prove to be as young as our initial estimate, then we are certainly sampling rejuvenation stage volcanism.
After more sampling and observation of the morphology at Site 05, we will move towards the rift zones of Kaula. Rift zones are long fractures in the crust. At Hawaii, rift zones are common to the islands, and are associated with the transport of magma in dikes during the shield stage of volcanism. Therefore our strategy of using Jason 2 on the Kaula rift zones is meant to deliver samples of Kaula's shield stage volcanism. Currently only one known sample of Kaula's shield stage has ever been collected, by Chief Scientist Michael Garcia, during a visit to the subaerial tuft of Kaula.

Presented by the School of Ocean and Earth Science and Technology at the University of Hawaii, with financial support from the National Science Foundation.