Figure G-54b is a field photograph of a mylonitic megacrystic (porphyritic) granite from a shear zone that strikes 330° and dips 20°SW. Mineral lineations are down dip. You are looking at a vertical outcrop, parallel to the strike of the shear zone (toward 330°) so that southwest (SW) is to your left and northeast (NE) is to your right. Describe in detail the type of movement on this shear zone. (Here is a generic example of a complete description: ‘‘reverse-sense movement, northwest side up.’’)

Transcribed Image Text:

SW Description of type of movement in the shear zone: Fig. G-54b Field photograph of mylonitic megacrystic granite for use in Problem 16.8. You are looking parallel to the strike of the shear zone (toward 330°). NE, northeast; SW, southwest. Scale bar is 2 cm.