USE OF TIME AND SPACE IN GEOLOGIC MAPPING: A VIDEO LOG STUDY

In this study, we integrate data capturing the physical actions, spoken thoughts, and navigation paths of geologists as they make a geologic map. Eight geologists wore a head-mounted video camera with an attached microphone to record their visible actions and their spoken thoughts, creating “video logs” while in the field. They also wore GPS units to record their position throughout the day. The GPS data and video logs are time-stamped, enabling the data sets to be synchronized. The research questions we aim to answer are: what are the differences and similarities in geologists’ use of time and space as well as their spoken thoughts during the making of a geologic map? How do these similarities and differences relate to expertise in geologic mapping or success in the task?

The participants, representing a range of expertise in geologic mapping, were asked to map a field area for which there exists a consensus understanding of the underlying geology (i.e. an “answer key”). We focus here on the portions of video logs recorded when the participants were all located in the same section of the map area with a series of key exposures of a major structural feature. The videos were coded using three different emergent themes: collecting data (e.g. taking strike and dip); recording data (e.g. writing in field notebook); and referencing (e.g. referring to topographic map or aerial photo). The times for which there was no applicable code, or when none of the above actions were visible, was also determined. The spoken thoughts were coded using four different emergent themes: knowledge, navigation, reasoning, and metacognition.

From analyses of the video logs, we find that all geologists are making constant reference to maps to identify location in the field. Geologists with more expertise in mapping are more constant in their collection and recording of data than those with less expertise. The participants who produced more accurate maps express thoughts indicating that they arrived in the area with predictions for what they would find based on a mental model of the geologic structure. The actions are used to test, support, or revise those ideas as needed.