The structure and stratigraphy within this newly defined rift are more complicated than in the Oregon-Idaho graben. We believe that this rift may have started to evolve prior to eruption of the Columbia River Basalt Group and remained active into the late Miocene. During mapping we define the structure, stratigraphy, and basic geomorphology within 7.5 minute quadrangles. We are particularly interested in the geologic evolution of the map area and how this fits into regional patterns. The map area selected for this summer is adjacent to map areas covered during the summers of 1994 to 1998.
Students work in two-person groups and field parties change daily.
The instructor is also mapping and works with a different student daily. We will spend time developing projects and the types of measurements or samples that are needed to successfully complete the project. Each week you and your project partners are provided field time to work on these projects. Projects initiated in previous years include gravity and magnetic surveys to detect major faults and possible ground water aquifers, geochemistry of basalt units and their stratigraphic relations, evolution of the Castle Rock volcanic center, correlation of welded ash-flow tuffs, evolution of rift lakes, and kinematic history and internal coherence of a landslide. This part of Oregon is high steppe characterized by hot, dry summers.