Named for town of Carefree, Cave Creek quad, northern Maricopa Co., central AZ. Type locality is Carefree basin, Cave Creek and Wildcat quads. Occurs as interfingering alluvial-fan and playa-lake clay sediments partially filling this small, structural, tectonically rising basin at northern edge of Basin-and-Range province; basin underlain with Middle Proterozoic basement rocks composed of meta-argillite--phyllite complex in west and coarse-grained granite in east; basin covers area 2 to 3 mi wide and 8 to 9 mi long; trends north 70 degrees west; shallow, with maximum depth of 2000 feet. Carefree formation is divided into late Miocene and early Pliocene (<13.4 Ma) Grapevine Member (1,000 feet thick) (eastern third and south-central parts of basin), Sombrero Member (160 feet thick) (north-central part of basin), Naked Girl Canyon Member (1,000 feet thick) (fanglomerate facies in northwestern and clay facies in west-central part of basin), Galloway Member (100 feet thick) (southwestern part of basin), and Church Member (80 feet thick) (northern base of Black Mountain) (all new), all moderately consolidated, largely fanglomerate and basalt derived from local sources; stated total thickness [at least] 1300 feet. [Total thickness of its five members adds up to at least 2340 feet]. Carefree Formation overlies Miocene (22.0 Ma) volcanic rocks as well as Miocene White Eagle Mine Formation (new). Age is late Miocene and early Pliocene based on constraining minimum radiometric date of <13.4 Ma of underlying White Eagle Mine Formation. Report includes geologic map and cross section, and stratigraphic nomenclature table.

Source: GNU records (USGS DDS-6; Denver GNULEX).