Obsidian Hydration and the Pinto Chronology in the Mojave Desert

This paper is an evaluation of three different chronological placements of the Pinto Period in light of obsidian hydration readings from the Stahl, or Little Lake, site (Harrington 1957; Meighan 1981) and the Awl site located at the west end of Drinkwater Basin on Fort Irwin (Fig. 1). The three chronologies selected are representative of different views concerning the beginning and ending dates for the Pinto Period and its cultural relationship to the earlier Lake Mojave Period (Fig. 2). Wallace's (1962) chronological placement of the Pinto Period sets a terminal date of A.D. 1 and an initial date of 2500 B.C., with a cultural hiatus separating the Lake Mojave and Pinto periods. Bettinger and Taylor (1974) place their Little Lake (Pinto) Period between 1200 and 4000 B.C., immediately following the Lake Mojave Period. Warren and Crabtree (in press) date the Pinto Period between 2000 and 5000 B.C., immediately following the Lake Mojave Period. These proposed beginning and ending dates for the Pinto Period, and the presence or absence of a preceding cultural hiatus, can be evaluated with data that include obsidian hydration measurements from the Little Lake and Awl sites, and available radiocarbon dates pertaining to the outset of the Gypsum (or Newberry) Period