Gila Formation


The Gila Formation is a geologic formation found along the upper tributaries of the Gila River in Arizona and New Mexico. Radiometric dating of interlayered lava flows yields an age of Miocene to Quaternary.

Description

The formation is primarily conglomerate composed of clasts derived locally. There are also occasional thin sandstone and tuff beds and basalt flows. Total thickness is.. Radiometric ages of interbedded basalt range from 12.1 Ma to 1 Ma.

History of investigation

The unit was first named as the Gila Conglomerate by G.K. Gilbert in 1875 from his participation in the Wheeler Survey.. By 1903 Ransome had mapped the unit into the Globe area. Wood divided the unit into the Bonita beds, Solomonsville beds, and Frye Mesa beds in 1960. In 1963, Heindl raised the unit to group rank and divided it into the San Manuel, Quiburis, and Sacaton Formations, but Krieger et al. removed the San Manuel and Quiburis Formations from the Gila and abandoned the Sacaton Formation, restoring the Gila to formation rank. Ratte et al. redesignated the unit as the Gila Formation based on its diverse lithology.

Footnotes