EXPERT-NOVICE STRATEGIES IN PROPOSING FIELD ROUTES DURING BEDROCK MAPPING

Field work is considered necessary to the development of geologic expertise. Additionally, bedrock geologic mapping is a key skill taught in field camps and courses. An important component of mapping is planning and executing a route through the field area that takes into account potentially important geologic features, areas of outcrop, and topography, as well as time and energy exerted by the mapper. To assess the importance of planning a navigation route through a field area prior to bedrock mapping, we compare routes proposed by geologists during a paper survey and actual routes used by geologists in the same field area. Participants in both groups spanned the continuum from mapping novice to mapping expert as self reported using questions from an experience survey. Survey participants (N=77) were recruited during GSA 2010 and were asked to propose a route for mapping an 172 acre study area in the Tobacco Root Mountains, MT using an aerial photo and topographic map of the field area. All data was imported into ArcGIS 9.3 for analysis. Routes drawn by participants on the aerial photograph were scanned, georeferenced and digitized. Field participants (N=67) were tracked using GPS during an actual mapping task of the same area. Length of participant route, spatial pattern of route and amount of previous mapping experience were compared for field and survey participants using 2-tailed independent T-tests. Routes of survey participants were significantly shorter than the respective routes of field participants. Geologists with mapping expertise spent a significantly greater portion of their route in areas critical to understanding the geologic structure in both paper survey and field settings. These results have implications for training students to identify and form hypotheses about geologic structures prior to arrival in the field, and to use these initial hypotheses to plan navigation routes that take advantage of critical areas, good rock exposure, and topography.