GEOL 352 Lecture Notes - Lecture 7: Slickenside, Great Circle, Stereographic Projection

• School: College of Charleston
• Department: Geology and Environmental Geosciences
• Course: GEOL 352
• Professor: Beutel

Document Summary

How to find the fold axis and axial plane using stereonets. A line parallel to the hinge line (the line/bar that the beds folded around) Anything not on the edge of the stereonet is dipping or plunging (exists at an angle to horizontal the further from the edge of the stereonet, the steeper the angle) The axial plane (or surface) is a plane that connects all the hinge lines. On a stereonet, the fold axis is where all the beds intersect (approximately) Lots of beds is messy so we use poles to the planes. A pole to a plane makes visualizing and manipulating the data easier but be sure you know what is a pole vs a line like a slickensides. To find the fold axis, rotate the stereonet until all the poles approximately line up on a great circle. The pole (90 degrees from that great circle) is the fold axis. Now we need to find the axial plane.