Paleosols in the Teotihuacan valley, Mexico: evidence for paleoenvironment and human impact
The Teotihuacan valley, located in the northeastern sector of the basin of Mexico, was settled byapproximately 1,100 BC. The first and largest prehistoric city in the Americas developed here in AD350550, reaching a population of around 125,000. The demise of the Teotihuacan state is now generallybe...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2003 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Redalyc-UNAM |
| OAI Identifier: | oai:redalyc.org:57220310 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=57220310 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias de la Tierra pollen paleosols phytoliths Teotihuacan human impact |
| Sumario: | The Teotihuacan valley, located in the northeastern sector of the basin of Mexico, was settled byapproximately 1,100 BC. The first and largest prehistoric city in the Americas developed here in AD350550, reaching a population of around 125,000. The demise of the Teotihuacan state is now generallybelieved to have culminated between AD 600650. Causes are attributed to global climate change,environmental degradation, economic and/or political upheaval, but no direct evidence has ever beenpresented to support these hypotheses. The study of paleosols contributes to the understanding of theenvironmental conditions that prevailed in the Teotihuacan region in order to better comprehend theirpotential relationship to cultural and economic events in the prehistoric past. The distribution of soils inthe region is directly associated with relief. Profiles at Cerro Gordo (3,050 m a.s.l.) and Cerro Patlachique(2,700 m a.s.l.) are associated with forest conditions, where paleosols are characterized by polygeneticprofiles with varying degrees of development. The older soils are represented by Luvisols. Soils in lowerpositions (Cerro Colorado, 2,390 m a.s.l.) are stratified and poorly developed, with evidence of colluvialdeposition and erosion. Soils with fluvic properties in the alluvial plain (2,2502,350 m a.s.l.) are alsopoorly developed and greatly influenced by erosive processes and intensive accumulation. Thosecorresponding to the Teotihuacan periods (2,0001,350 yr BP) show multiple indicators of human impact.Micromorphological evidence indicates intensive agricultural activities (deforestation, burning,compaction, and erosion). The presence of carbonates in underlying strata is related to changes inhumidity. Phytoliths identified from the same strata indicate alterations in vegetation through time thatreflect variable conditions of temperature and humidity. The results clearly reflect environmentalmodification by human populations from the initial period of prehistoric settlement up to present.Furthermore, the evidence suggests that a major impact of the prehistoric city on the landscape resultedfrom unmanaged exploitation of forest resources that provoked intensive erosion and significant changesin the hydric conditions of the region. |
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