Archaeology and recent volcanism in the Zacapu lacustrine basin (Michoacán, Mexico): Fieldtrip guide

The Michoacán-Guanajuato Volcanic Field in the Trans-Mexican Volcanic Belt contains the largest concentration of monogenetic vents on Earth associated with a subduction-related continental arc, holding more than 1400 edifices consisting of abundant scoria cones, ~300 medium-sized shields and domes, and ~22 maars. Paricutin (1943-1952) is the youngest volcano of this field and together with Jorullo (1759-1774) the only monogenetic volcano formed since the Spanish conquest (1519-1521) in Michoacán. Both volcanoes are said to be monogenetic because they were produced entirely by single eruptions and hence will presumably never erupt again. Nonetheless, another monogenetic eruption will certainly occur in the future and form a new volcano on Michoacán territory. In order to minimize losses of life and property it is desirable to learn more about these types of eruptions and with this knowledge design preventive strategies. In recent years, it has become clear that monogenetic eruptions can be quite diverse in style and duration. For this reason, we will visit different examples of monogenetic volcanoes (e.g., maars, scoria cones, isolated lava flows) to cover the spectrum of monogenetic volcanism and discuss the possible causes of its eruptive variability. Most of the volcanoes in the Michoacán-Guanajuato Volcanic Field formed well before the arrival of Early Human to this area, but dozens of them erupted during the Holocene impacting directly the environment and early populations. A prime example is the Malpaís de Zacapu cluster of volcanoes at the western margin of Zacapu lake, where large cities (e.g., El Palacio, Malpaís Prieto, etc.) were constructed on the rugged surface of Late Holocene lava flows in pre-Hispanic time. Subsequent eruptions induced temporal abandonment and resettlement of the area, as revealed by the recent application of LiDAR (Light Detection and Ranging) imagery and modern dating techniques. These studies allowed to gain greater insight into the prehistory of this area, which holds the roots of the Tarascan empire that flourished during the Postclassic period (AD 900-1521) of Mesoamerican archaeology around its capital Tzintzuntzan at the shore of Lake Pátzcuaro. The excursion is aimed at providing greater insight into the complex interplay between volcanic activity and human settlement in the lacustrine environments of the highlands of Michoacán. This guidebook is designed as a companion for a post-meeting field trip but might also be a handy tool for those wishing to visit the area with condensed and updated information at hand. The guide contains excursions to maars and springs of the Zacapu lacustrine basin (1 day/1 night), archaeological sites (pre-Hispanic ancient cities) on the young andesite lava flows of the Malpaís de Zacapu monogenetic cluster (1 day/1 night), and to the archaeological sites of Tzintzuntzan (the capital city of the Tarascan empire) and Angamuco (built on young lava flows of Rancho Seco volcano), both located at the SE margin of the Pátzcuaro lake basin. The trip starts and ends at Morelia with overnight stays at the town of Naranja, near the modern city of Zacapu.