RECONNAISSANCE OR FOCUSED FIELD EXPERIENCES: WHAT WORKS?

Two summer's field work during an REU project to map and sample Precambrian basement rocks in Yellowstone National Park and along the Beartooth Highway produced very different experiences for the two student cohorts. During the first year, the key research questions and geologic setting dictated that reconnaissance mapping and sampling was conducted over an area that was underlain by a metamorphosed turbidite sequence that was intruded by two quartz monzonite plutons along a 25 mile corridor along the Black Canyon of the Yellowstone River and adjacent major drainages. The primary focus of this work was to characterize the lithologic sequences, regional structural geology, metamorphic grade, and to collect samples for follow-on geochemical and geochronological analysis. Much of this work was done in small groups as they targeted distinct and dispersed research targets and 15 mile hikes were the norm. The second year's project was focused on predominantly plutonic rocks in the Slough Creek area and near Cooke City to the east. These study areas were significantly smaller in scale, but presented complex intrusive relations among diverse igneous rocks ranging in composition from granite to diorite. Snowpack and flooded streams denied access to distal field targets, so field work the second year was not as physically demanding, Much of the work was done with the whole group contributing to data acquisition at each field site. Because we were forced to work in a smaller area, the students had the opportunity to a) revisit outcrops to take a second look at relations in light of observations made elsewhere, b) create detailed outcrop-scale maps to unravel complex relations, and c) engage enrichment activities related to the regional geology (e.g. mine reclamation). Both cohorts of students have self-reported significant gains in confidence and ability to describe rocks, measure structures, and conduct novel research. The first cohort exhibited greater independence and responsibility for focused research objectives; the second cohort worked collaboratively and holistically to produce comprehensive, detailed descriptions of the field sites. Both groups contributed materially to the overall REU research objectives, and depth and breadth of field experiences are both important for student training in the field.