'Octopus Rock' is an outcrop of Oracle Granite in Soldier Canyon of the Santa Catalina Mountains that hosts a bifurcating granitic (pegmatitic?) dike system. Photo by Esty Pape, (April 16, 2016). The Mesoproterozoic Oracle Granite (~1,400 Ma) is metamorphosed to gneissic grade. The light-colored rocks - the octopus limbs - comprise pegmatitic granitic rocks and quartz veins of the 50-million-year-old Wilderness Suite leucogranites. Online resources: Bezy, J.V., 2016, A Guide to the Geology of the Santa Catalina Mountains, Arizona: The Geology and Life Zones of a Madrean Sky Island. Arizona Geological Survey Down-to-Earth # 22, 83 p. https://library.azgs.arizona.edu/item/DTES-1552428346471-69
Photographer: Esty Pape
Photo Date: circa 2016