Stop 1: Today was our first day in the Long Valley area. Our group, which includes undergraduate and graduate students and two professors, gathered into a van and took the gondola up to the summit of Mammoth Mountain. From there, we were able to get an excellent perspective on Long Valley Caldera and its relationship to Sierra Nevada range front faulting. We also discussed the Mono-Inyo Craters volcanic chain and the much older intracaldera fill deposits that make up the Minarets.
Stop 2: On our drive back to Mammoth Lakes, we stopped to learn about pumice fall deposits formed by explosive eruptions. We also pondered the origins of lithic-rich layers and discussed how identification of the different lithic clast types can be used to infer vent location. We collected several bags of lithics, and a later careful examination showed that there were at least 10 different compositional types in the deposit.
Stop 3: The third stop – Deadman Creek Dome – reveals the many wonders of magma mixing. Here, you can see crystal-poor rhyolite swirled around and within crystal-rich material.
