Holocene volcanic eruptions of the Malpaís de Zacapu and its pre-Hispanic settlement history

Abstract

The Michoacán-Guanajuato volcanic field (MGVF) hosts >1,400 monogenetic structures younger than 5 Ma. Here we focus on the Malpaís de Zacapu Late Holocene cluster located in the western part of the Zacapu lacustrine basin, situated in the heart of native Purepecha province. The Malpaís de Zacapu comprises four distinct eruptions: the Infiernillo lava flow emitted at ~1450 b.c.; Malpaís Las Víboras, a purely effusive eruption at ~1000 b.c.; the Capaxtiro compound lava flow at ~150 b.c.; and the most recent eruption, the Malpaís Prieto lava flow at ~a.d. 900. Although these lava flows are not inhabited today, they were densely populated in pre-Hispanic times (before a.d. 1521), especially during the Milpillas phase (a.d. 1200–1450). Volcanological studies (geochemical studies and detailed mapping using high-resolution DEM from LiDAR) allowed us to characterize these eruptions in terms of their magma source (rock chemical composition, mineral assemblage), age (radiocarbon and paleomagnetic dating), magnitude and dynamics (volume, morphology of the deposits), as well as lava flow emplacement duration. The findings allow us to infer the potential impact that these eruptions had on the pre-Hispanic settlement history of the area.

Pueblos viejos–pueblos nuevos: transformación del paisaje en el norte de Michoacán (México) a inicios del período novohispano (siglo dieciséis)

“…En ese entonces, Mich. 68 constituye un sitio sobre todo residencial y agrícola, relacionado con el foco de poblamiento epiclásico de la franja oeste del Malpaís de Zacapu (véase Pereira et al 2023). Su abandono a principios del posclásico temprano, al igual que buena parte de la región, seguramente debe ponerse en relación con la erupción del volcán del Malpaís Prieto alrededor de 900 d.C. (Mahgoub et al 2018; Reyes-Guzmán et al 2023). A mediados del siglo trece (fase Milpillas), se inicia una nueva ocupación, muy probablemente vinculada al fenómeno urbano del Malpaís.…”

Evolution of ancient farming systems and demography in the volcanic highlands of Zacapu: A model drawn from Geoarchaeology and archaeogeography

“…Within the Malpaís itself, our work allowed us to affirm the geopedological diversity beyond the omnipresence of rock outcrops (Nudilithic Leptosols). Far from the monolithic entity its name suggests, the Malpaís is actually a mosaic of lava flows (Reyes-Guzmán et al 2023). Their different ages imply different agronomic characteristics: from the barren tenth century lava flow of the Malpaís Prieto to the rather fertile “old malpaís ” that constitutes the Late Pleistocene Mesa del Bolsón (100–30 Ka B.P.…”

“…During the following Palacio phase ( a.d. 900–1200), the Malpaís and its vicinity were broadly abandoned. The eruption of the Malpaís Prieto lava flow was most likely the main factor triggering the population movements (Mahgoub et al 2017; Reyes-Guzmán et al 2023). The process of urbanization, beginning in the mid-thirteenth century, remains the major settlement event in the history of the area (Forest 2014, 2023; Michelet et al 2005).…”

“…Going back to the case of Mesa del Bolsón, the “cultivable area” consists of the Mid-Pleistocene lava flow where the site is located and the surrounding geoforms. However, since this approach sought to address all arable areas and not just those identified archaeologically, we had to take into account somehow the lands located east of the settlement that were covered by the formation of the Malpaís Prieto lava flow in the early tenth century (Mahgoub et al 2017; Reyes-Guzmán et al 2023). Additionally, we also had to consider the possibility of Epiclassic houses buried under the lava.…”