Cross-Sections Depict units as they would appear in a vertical slice through the crust, like in a cliff exposure. Cross-sections can be constructed by extrapolating information plotted on a geologic map (strikes-and-dips and locations of contacts with respect to topography).

Depicting Features in the Subsurface Observe the three ways geologic features in the subsurface can be depicted (shown) Block diagram Infer the sequence of events that formed this area INSTRUCTIONS TO STUDENTS Observe the three ways geologic features in the subsurface can be shown Infer the sequence of events that formed this area (described on next slide) EXPLANATION Block diagram: 3D depiction Geologic cross section: slice through subsurface Stratigraphic section: idealized sequence of layers Stratigraphic section Cross section 02.06.b1

Geologic Cross-Sections 2-dimensional vertical slice through a geologic map. Start with a topographic profile. Transfer contacts and structures onto topographic surface. Project contacts and structures into subsurface. Use field relations, mapping, and other constraints to infer possible subsurface geology.