Wednesday - November 4, 2009 - Maps, Mountains, and Underwater Volcanoes!
Student Argonaut Ben Brannan

Today was our last day shooting Mission 4. We had a nice breakfast at a nearby restaurant and then got down to work. Our first activity involved going down to the beach with Dr. Smith. In the demonstration we shaved the top layer of sand off with the shovel. This produced a pattern of ridges, similar to those produced when the top plate scrapes sediments off of a subducting plate. It was a great demonstration.

Dr. Smith and the Argo Ben using shovels and sand to illustrate subducting plates.

The ridges that are formed by pushing a shovel across sand or snow resemble some of the land features that form during subduction.

After this we headed to the Hatfield Marine Science Center to work with NOAA to learn more about local ocean floor mapping. Dr. Steve Hammond introduced us to the facility and gave us some background information on the area. Off the coast of Orego,n the Juan de Fuca plate is subducting under the North American plate, creating underwater volcanoes and earthquakes.

Next, Dr. Bob Embley gave us a presentation that went a little more in depth. We learned about the methods of sea-floor mapping and of locating underwater tectonic activity. They showed us some of the very detailed maps of the Juan de Fuca plate that they had been working on for the past 30 years. There are a few underwater volcanoes in this area, especially along the plate boundary. NOAA uses some of the Navy's sensors to locate these earthquakes and volcanoes. Scientists here are just beginning to study volcanoes that were unreachable before. We even got to see some incredible new video footage of underwater eruptions, which was very cool. NOAA will be publishing these soon, and we were one of the first groups to ever see them.

Now that we had a better idea of what geologists study on a local level, Dr. Smith showed us some amazing maps on both the international and local level. We talked about and compared and contrasted the maps. Looking at the maps really helped us comprehend and visualize what we have been learning for the past couple days. It was interesting to see the relative scale of the mountains we saw on land, compared to the vast mountain ranges of the oceans.

To wrap up Mission 4 we took a road trip to Mary's Peak, just outside of Corvallis. On the way up we stopped by a cliff. Dr. Smith asked us what kind of rock we thought it was, so it became my job to break off a piece of the cliff with a hammer to help identify it. After a couple whacks, we broke a chunk off, and we could plainly see individual grains in the rocks, so we decided that it was sedimentary rock.

Dr. Smith explained that the rock in the cliff was very similar to the core sample that Dr. Goldfinger showed us yesterday. The sand or mudstone that we identified was like the large sections of mud that came from landslides resulting from underwater earthquakes. There were also small layers of clay or shale above the sandstone that represented the slow sediment build up in between landslides.

Finally, we traveled to the top of Mary's Peak. Once there, us Argonauts stood with Dr. Smith and discussed what we had learned, what we liked and found interesting, and how it might affect our future. I don't know if I will go into the field of ocean-floor mapping, but it is up to our generation to finish this important task.

Comparing maps with Dr. Smith and the Hatfield Marine Science Center.	The layers of different types of rocks reveal a history of mudslides and underwater earthquakes in the region.
Atop Mary's Peak, we were able to see Mount St. Helens and Mount Hood while we wrapped up our mission.