The Santa Catalina Mountains are part of a metamorphic core complex that formed 25 to 20 Ma (Oligocene-Miocene) during extension that preceded ongoing Basin and Range extension.
Bykerk-Kauffman, A., 2008, Geologic Map of the Southeastern Santa Catalina Mountains, Pima County, Arizona: Arizona Geological Survey Contributed Map CM-08-A, map scale 1:24,000, 2 map sheets. https://library.azgs.arizona.edu/item/AGCM-1552430762408-627
Photographer: Anna Bykerk-Kauffman
Photo Date: 2008