Geology of the Willcox playa, Cochise County, Arizona
— Schreiber, Joseph F., Jr.

Pluvial Lake Cochise, located in Cochise County, southeastern Arizona, was one of many lakes present during the late Pleistocene Epoch in the Basin and Range province of the western United States (Feth, 1964). Lake Cochise later dried up; the desiccated lake bed is now known as Willcox Playa or Willcox Dry Lake.

 

Willcox Playa and surrounding area was studied by the author and his students for three years in 1962-65 (Pine, 1963; Pipkin, 1964; Robinson, 1965; Wilt, 1965). A paper covering the results of these investigations was printed in the Playa Lake Symposium volume by the International Center for Arid and Semi-Arid Land Studies (ICASALS) and Department of Geosciences, Texas Tech University, Lubbock, Texas, in 1972 (Schreiber and others, 1972). These studies provided a frame-work for the interpretation of the sedimentation history of the Willcox Playa area during the late Wisconsin and in post-pluvial times. Field and laboratory work has been continued intermittently by the writer since mid-1965.

 

0. E. Meinzer first studied the Willcox Playa area as part of a larger investigation of the geology and water resources of Sulphur Springs Valley in 1910-1911 (Meinzer and Kelton, 1913). He gave the name Lake Cochise to the Pleistocene lake that had once occupied Willcox basin. Meinzer's thorough work was a constant guide and inspiration throughout our 1962-65 field studies. More recent U.S. Geological Survey publications include a reconnaissance geological map of the playa and surrounding area by J. R. Cooper (1960), a study of the fluoride content and salinity by Kister and others (1966), and a water-supply paper by Brown and Schumann (1969) that covers the geohydrology in text discussion and with maps.