Geography of ancient geometric earthworks and their builders in southwestern Amazonia - UTU Research Portal

A1 Refereed original research article in a scientific journal

Geography of ancient geometric earthworks and their builders in southwestern Amazonia

Authors: Kalliola, Risto; Pärssinen, Martti; Ranzi, Alceu; Seppä, Iiro; Barbosa, Antonia Damasceno

Publisher: INST NACIONAL PESQUISAS AMAZONIA

Publishing place: MANAUS

Publication year: 2024

Journal: Acta Amazonica

Journal name in source: ACTA AMAZONICA

Journal acronym: ACTA AMAZON

Article number: e54hu22351

Volume: 54

Issue: 4

Number of pages: 21

ISSN: 0044-5967

eISSN: 1809-4392

DOI: https://doi.org/10.1590/1809-4392202203511(external)

Web address : https://doi.org/10.1590/1809-4392202203511(external)

Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/458940065(external)

Abstract

Geometric earthworks are evidence of ancient human activity in western Brazilian Amazonia. We used a review of existing and new data to map earthworks across 27,569 km2 of deforested areas in southwestern Amazonia using satellite imagery. We developed a conceptual basis for the classification of earthworks based on their structural characteristics using fuzzy sets. We recorded 1,279 structures with a distinctive core density zone. Most of the structures displayed geometric shapes, but they varied in construction accuracy. Geoglyphs accounted for 80% of all objects, with geographically variable shapes and enclosure areas. Other earthwork types included associated embankments, solitary embankments and mound sites. The abundance of earthworks provided evidence of strong pre-European human influence on the study area. A 10-km buffer around each earthwork included 75% of recent deforestation areas and 25.7% of standing forest, suggesting a significant potential for the presence of further earthworks in this ancient anthropogenic landscape and its possible far-reaching ecological legacy. The available radiocarbon data confirm a long-term anthropogenic impact in the study area, with ceremonial geoglyphs indicating activities over a thousand years old and other structures revealing more recent cultural transformations.

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Funding information in the publication:
We extend our gratitude to our collaborators at our home institutions, James Q. Jacobs, Francisco R Nakahara, and the other discoverers of ancient earthwork sites. We also acknowledge the Academy of Finland for funding research projects 296406 (RK) and 297161 (MP) . In Brazil, the research was authorized by the Instituto do Patrimpnio Historico e Artistico Nacional (IPHAN license #01423000336/2017-11) . Our heartfelt thanks go to our long-term close collaborators Denise Schaan and Heli Paerssinen, and we dedicate this research to their memory.