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31 January 2020
Friday fold: tension gashes near Sunflower, Arizona
Reader John Christian shared these folds with me via email last week. They are quartz veins in slightly metamorphosed Precambrian igneous rocks found near Sunflower, AZ in the Mazatzal Mountains. The second photo is a close-up shot of the curviest, cleanest batch of folds from the first shot. These are beautiful examples of folds in similarly oriented quartz veins; we call them “en echelon” for the way you have a …
Callan Bentley is Associate Professor of Geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.