ASBOG Practice Exam

What type of outcrop pattern is produced by a geological unit with vertical bedding?

1. Straight lines across the topography of the valley

2. Curved lines following the valley slopes

3. Irregular patterns depending on erosion

4. Circular patterns around geological features

The correct answer is: Straight lines across the topography of the valley

A geological unit characterized by vertical bedding typically produces straight lines across the topography of the valley. This pattern arises because, with vertical bedding, the layers are oriented perpendicular to the ground surface. Consequently, when these layers are exposed on topographical surfaces, such as in valleys, they will display a linear form following the natural gradient of the land. The straight lines are indicative of the uniform exposure of the vertical bedding, and the dip of these layers may further influence their appearance based on local topography. This contrasts with other patterns; for example, curved lines would suggest a more undulating layer structure, while irregular patterns imply varied erosion, which is not typically associated with uniformly vertical bedding. In addition, circular patterns usually indicate geological features like domes or basins, which would not arise from vertical bedding arrangements. Understanding these outcrop patterns is vital for geological mapping and interpretation as they reflect the structure and orientation of the rock units beneath the surface.