This paper critically analyses the traditional approaches for explaining the origins and development of Formative Period societies in the San Pedro de Atacama oasis. We evaluate the local formative process in the axes of the oases with Calar and Puripica, following the course of the Vilama River. We then propose an explanation that allows us to understand the Formative societies of the Puna Salada as well as their articulation to the intra, and inter, regional traffic of goods, which characterized the development of these societies' social complexity in the following periods. To build this model we establish a sequence for the Formative Period occupations, their absolute dates, and determine their nature as well as their incorporation into the caravan practices typical of San Pedro de Atacama.