Dispatches from Sea >>
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| March 2007 |  Laura Preston, educator, UNH/Salem High School, Salem, NH. |
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| April 2007 | |||||||
April 7, 2007
Okay, now about those rocks. First of all, what happens to them after they come onboard, and secondly, why do the scientists want them?
Luckily, we have Dr. Ian Ridley from the United States Geological Survey with us on this trip! Remember last week when Ian taught us how to cut rocks? Well, now we are all experts and let me tell you….there are sure a lot of rocks to cut! First though, the rocks are set out on a large table with their respective numbers where a picture of each is taken and the rock’s characteristics are written on a form. After that, the rock is taken to the processing room where the samples are cut to certain specifications. Some of the researchers want to make thin sections of the sample, so a small piece is cut off (very scary), and some want larger slabs cut (not so scary!). Some want those as well as glass shards, which we chip, and chip, and chip until we can’t chip anymore. It’s probably best to wear gloves, because glass really does cut your hands and those tiny pieces are a real pain to pull out of your fingers!
 Ian examines a sample. |
 And gives explicit instructions. |
 Jen Laliberte and John O’Brien get started with descriptions. |
Now for the important part. Why are they so interested in these samples? Chief Scientist, Emily Klein (Duke University) wants to perform chemical analysis on the rocks to determine the components of the sample. This will help her understand the composition of the mantle in this area. Because the melt comes up extremely hot and “freezes” upon impact with the water, glass forms immediately. This glass is an indirect “window” to the mantle composition. Hence the chipping and chipping that we do in processing the rocks! Adam Soule (Woods Hole Oceanographic Institute) is a volcanologist and is interested in the volcanoes and lava flows at the East Pacific Rise. By looking at the rock samples, he can determine the viscosity of the magma, allowing him to understand the effusion rate (rate of flow) and how the magma moved from the subsurface, and on the seafloor to get where it currently resides.
 Arriving in the Main lab. |
 Our description table. |
 Straight from the seafloor! |
 Very interesting… |
 See the glassy “rind”? |
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