Earth Geology Rock Structures Joints

Joint Patterns 

Throughout the Bryant Watershed area and indeed the regional area two distinct sets of joints are observed wherever bedrock is exposed. Joints are simple fractures in the rock that form in response to regional forces or perhaps just to the release of pressure. One set of joints is oriented NW - SE and is essentially parallel to the general trend of the Mansfield Fault Zone. The second set is roughly at right angles to the first (Figures 1 and 2). 

FIGURE 1  Fracture sets in Roubidoux Sandstone in small White's Creek tributary.

FIGURE 2  Fracture sets in Roubidoux Sandstone in Bryant creekbed north of Highway 76. Low water bridge in upper left.