New Perspectives on Holocene Volcanism in Ecuador and its Repeated Impacts in the Jama Valley: Towards a Distal Tephra Geo-archive

Abstract

Sustained field archaeological investigation in the Jama Valley of the Manabí coast from the 1980s and 1990s has documented the presence of three tephra layers representing large-scale volcanic eruptions (VEI = 4-5) emanating from the Quito basin and surrounding areas, all of which had cataclysmic impacts on various pre-Hispanic cultures that resulted in the abandonment or depopulation of the valley over several decades in two cases and several centuries in one case. These were cultural occupations of the Valdivia Terminal (Phase 8a), Chorrera, and Jama-Coaque I (Muchique Phase 1) cultures that extended from ca. 2030 BCE to 90 CE and that they were affected, respectively, by eruptions of the Guagua Pichincha, Pululahua, and again by Guagua Pichincha volcanoes, respectively. A more recent tephrochronological investigation in coastal Ecuador, carried out by Vallejo Vargas (2011), has documented the presence of at least five additional Holocene volcanic events in this distal landscape (VEI = 4-6), but, in this case, without archaeological associations. This article presents new archaeological information about this complex tephrochronological sequence of eight eruptions with a total duration of 5700 years (5940 to 240 BP) and emanating from five different highland volcanoes. These repeated ruptures by natural disasters and their varied impacts on the cultural sequence contribute to our understanding of the different pre-Hispanic cultural occupations and inferences regarding the tempo and rhythm of cultural and sociopolitical change in each archaeological phase through time.