Mapping in SW Montana, and Crooked River, Oregon
The third course in our Summer Geology Field Camp sequence will be split into two projects: one taught near Dillon, MT, and one taught in in the Crooked River Basin of eastern Oregon. These projects provide experience with geologic mapping, field stratigraphy, vertebrate paleontology, and tectonic geomorphology. The group will first will spend about a week mapping folded sedimentary rocks in the Frying Pan Gulch area (shown below), near Dillon, MT, and later will focus on geologic mapping and field paleontology in eastern Oregon.
1. Frying Pan Project
Work for this project will help students develop skills that are needed for all kinds of geologic field mapping and field study, with an emphasis on sedimentary rocks and stratigraphy. We will emphasize accurate field locations, placement of lithologic contacts on the map, thorough descriptions and interpretation of map units, and synthesis of map-scale structures. Ultimately, we will see that these rocks record the regional evolution of the Rocky Mountains region prior to and during deposition in a large Mesozoic foreland basin.
2. Crooked River Vertebrate Paleontology
Students will learn field methods in paleontology, including mapping the distribution of fossils over the landscape, collecting fossils with data on their location, taphonomy, identity, and lithologic and stratigraphic context. We will also use field identification of fossils to establish biostratigraphic context of our finds. We will be working in the Crooked River Basin, in the Oligocene and Miocene rocks of the Mascall, Rattlesnake, and John Day Formations. This time period has produced some of the most spectacular fossils in the terrestrial fossil record of Oregon. John Day Fossil Beds National Monument manages fossil resources from rocks of the same formations in the John Day Basin to the north; we will be visiting the Monument in a field trip prior to our field work. The Crooked River Basin has a less well-known fossil history that we will be working to describe. The areas where we will be working have, in recent years, produced scientifically important fossils, especially of small vertebrates (such as rodents and snakes) and of carnivores that have not previously been described from these formations in spite of more than 100 years of paleontological work. The complex topography of Oregon has given rise to biogeographic differences between spatially separated sites, which has given the Crooked River fauna a very distinct group of terrestrial vertebrates from the John Day assemblage to the north. The final project will include a map and a written report.