FIRST STEPS TOWARDS MAKING AND ASSESSING A VIDEO GEOLOGIC CROSS-SECTION OF THE USA FOR USE IN THE CLASSROOM

The ability to synthesize various geologic information and draw cross section is a key geologic skill. It is our opinion that most students cannot draw a simple E-W cross-section across the USA, from Moho to the surface, mostly because they never seen one. Introductory textbooks contain good cross-sections and block diagrams of geologically interesting parts of the USA, but none contain a cross-section of the whole country. Nothing about cross-sections through continents is mentioned in the Geoscience Concept Inventory: v.3. The USGS distributes cross-sections of all 48 contiguous states, but the 1:1 scale makes them very thin and impossible for students to understand – after all, our continent is much wider than it is thick. Very few cross-sections depict the relative thickness of continental crust and continental lithosphere or the various crustal terranes that make up our nation. We believe it’s essential for upper-level geoscience students to understand the three-dimensional geology of the land beneath them, at least to the Moho, and perhaps to the base of the mantle lithosphere. To rectify this, we plan to make a series of short videos to capture the geology beneath an imaginary “GeoBus” as we drive the length of I-80 from New York City to San Francisco CA, breaking this up into 4 segments: NYC to Chicago, Chicago to western Nebraska, W. Nebraska to Salt Lake City, and Salt Lake City to San Francisco. We will first quiz UTD geoscience students to find out how much or how little they know about the subsurface to guide the geologic story we tell in our videos. We invite other undergraduate instructors in universities and community colleges to join in this assessment. After we make the videos we will assess them in the classroom to see if and how much the videos aided students’ understanding. Please let us know if this project is of interest to you and if you would like to help in the classroom assessment exercises.