Dr. Randy Keller : Mission Goals
This expedition was for the purpose of learning how the chain of seamounts that we were studying formed. They are volcanic, and the eruptions occurred on the sea floor. In the long term, we would like to know sort of the bigger picture of how seamounts in general tend to form, especially those in the Gulf of Alaska. All over the ocean floor, there are thousands and thousands of seamounts that we could never hope to visit them all. But understanding fundamentally how they form and why will tell us a lot about why the ocean floor looks the way it does.
One of the most exciting things we found on this mission was some of the beautiful volcanic landforms that we saw on the maps that we were creating. For the first time, we had these high resolution maps of the seamounts, and we saw some amazing lava flow features that are still preserved even though they are millions of years old that look just like the ones you see forming today on Hawaii.
This is an example of the types of rocks that we look for to determine the age of a seamount. Here is a volcanic rock taken from a volcano. To determine how old it is, we need to bring it into the lab, and either take a small core of it, like this, using a drill, or in some cases, we’ll crush the rock into small grains. Or maybe even remove the minerals from it and make a separate concentration of certain types of minerals, and use those as our samples to put through the dating machine and determine how old the volcano is.
Another interesting thing that I notice on expeditions like this one to the Gulf of Alaska, was how important the rocks are to the biology that live down there. Many types of biology only like to live in rocky areas. They don’t like muddy parts of the seafloor, so they look for rocks to attach themselves to, so that they can find food in the passing ocean currents.