Day 11

We took a look at the Gabrokargigar Craters Natural Monument. These picturesque scoria cones represent some of the most recent eruptions of their type in Iceland, estimated to be less than 3600 years old. There are three craters in total: Stora Gabrok (big), Litla Gabrok (small), and Gabrokarfell (just right). By 1962, Litla had mostly disappeared due to gravel mining, a popular industry in Iceland due to the abundance of volcanic rock which is of commercial value. The cones are composed of alkal olivine basalt, which is common for similar cones in Iceland. At the top of the largest cone we took a moment to discuss its formation and magmatic composition, taking a closer look at the olivine and plagioclase phenocrysts scattered throughout the rock with our hand lenses. We also partook in an activity where we tried to reconstruct the geologic timeline of the area using only our eyes to scan the geological features around us, hoping to put arrange these features by age of formation from oldest to youngest. It is a nearly impossible task in reality, given our distance from the features themselves (sans the craters) and lack of sophisticated dating techniques, but we ended up coming up with some conclusions that were almost certain and some that were at least believable. It was really a moment where we got the entire group, including the SUS majors, to think like real world earth scientists doing field observations, and it was nice to apply something I had practiced doing with pictures in the classroom to a real world setting.