Humans as geomorphic agents: Lidar detection of the past, present and future of the Teotihuacan Valley, Mexico

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As humans are the primary geomorphic agents on the landscape, it is essential to assess the magnitude, chronological span, and future effects of artificial ground that is expanding under modern urbanization at an alarming rate. We argue humans have been primary geomorphic agents of landscapes since the rise of early urbanism that continue to structure our everyday lives. Past and present anthropogenic actions mold a dynamic "taskscape" (not just a landscape) onto the physical environment. For example, one of the largest Pre-Columbian metropolitan centers of the New World, the UNESCO world heritage site of Teotihuacan, demonstrates how past anthropogenic actions continue to inform the modern taskscape, including modern street and land alignments. This paper applies a multi-scalar, long durée approach to urban landscapes utilizing the first lidar map of the Teotihuacan Valley to create a geospatial database that links modern and topographic features visible on the lidar map with ground survey, historic survey, and excavation data. Already, we have recorded not only new features previously unrecognized by historic surveys, but also the complete erasure of archaeological features due to modern (post-2015) mining operations. The lidar map database will continue to evolve with the dynamic landscape, able to assess continuity and changes on the Teotihuacan Valley, which can benefit decision makers contemplating the stewardship, transformation, or destruction of this heritage landscape.
Data Availability: Quantitative data is reported in the supplementary information. The lidar data is part of Mexico's cultural patrimony and contains highly sensitive information including the exact location of archaeological features that may attract looters. Researchers seeking access to this resource must contact the Instituto Nacional de Antropología e Historia (INAH consejo.arqueologia@gmail.com ) which is currently establishing guidelines for the dissemination of lidar data in Mexico consistent with the protection archaeological sites.

Copyright: © 2021 Sugiyama et al. This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Introduction

We live in the Anthropocene, where humans are principal agents conditioning environmental and climatic processes on earth. Geologists and archaeologists recognize anthropogenic alterations cause global changes and that deep-time human environmental impacts prohibit evaluation of "pristine" landscapes [1–3]. Wilkinson [4], for example, estimated that human geologic agents denude the earth's surface at roughly ten times the combined rate of glaciers, rivers, and other natural processes. In this paper we present a multi-scalar, long-dureé approach to recording the Teotihuacan Valley, the site of a flourishing metropolis from CE 1–550 and one of the most anthropogenically altered landscapes in the ancient New World. We apply lidar technology to detect, protect, and archive one of humanity's most numinous feats of environmental alteration: the ceremonial production of an enduring urban landscape. We argue that archaeologists are uniquely situated to contribute valuable insight into the continuity between past and present landscapes [5–7].

Every year, millions of visitors are drawn to Teotihuacan's breathtaking ritual precinct. The grand axial spine…
Nawa Sugiyama, Department Of Anthropology, University Of California-Riverside, Riverside, Ca, United States Of America, Saburo Sugiyama, School Of Human Evolution, Social Change, Arizona State University
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