GEOLEX database Geologic Unit: Yavapai Usage: Yavapai Supergroup (AZ) Yavapai Schist (AZ*) Age: Precambrian* Proterozoic, Early* Geologic Province: Southwestern Basin and Range region* Areal Extent: AZ(c)* Type Locality: Not stated. Named for extensive development in Yavapai Co., AZ (Jaggar and Palache, 1905). [From US geologic names lexicon, USGS Bull. 896] Subunits: SUPERGROUP STATUS (alphabetical) --all in AZ: Black Canyon Creek Group, Bradshaw Mountains Group, Mayer Group. Unit Name History: Named Yavapai Schist (Jaggar and Palache, 1905). Revised to Yavapai Group (Wilson, 1937 [abs.]; 1939). Revised to /Yavapai series, divided into Bridle Formation, Butte Falls Tuff, Hillside Mica Schist (all new) (Anderson and others, 1955). Revised, divided into Ash Creek and Alder Groups (Anderson and Creasey, 1958). Revised to provincial time-stratigraphic term; Isotopic dating (Anderson and others, 1971). Not used (Conway and others, 1986). [According to GNU records (USGS DDS-6; GEONAMES), Yavapai Supergroup includes Black Canyon Creek, Bradshaw Mountains, and Mayer Groups (explanation and reference not given.)] Note: If you need more information, please contact Nancy Stamm (nstamm@usgs.gov). Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys. "No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses (). Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]). U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA URL http://ngmdb.usgs.gov/ngmdb/ngm_catalog.ora.html Database project personnel Last modified: 7-Jan-2007