T102 Geoarchaeological Insights into Paleoenvironmental Reconstruction and Cultural Dynamics (Posters)

Monday, 23 September 2019
9:00 AM - 6:30 PM
Hall AB, North Building

GEOARCHAEOLOGICAL EXAMINATION OF CULTIVATED SOILS AT LA PLAYA, AN EARLY AGRICULTURAL PERIOD SITE IN SONORA, MEXICO

Paper number: T102-4
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

The La Playa archaeological site is located on the southern floodplain of the Boquillas River in Sonora, Mexico. This site has evidence of a Cienega phase Early Agricultural period earthen irrigation canal system (800 B.C.- A.D. 200). Due to rapid modern floodplain erosion, most of the irrigation canals have been destroyed. Low-energy sheet wash erosion has destroyed many of the agricultural fields, removing cultivated soils and leaving behind the rock-lined field borders.

Magnetic gradiometry surveys at La Playa identified 8700 m2 of intact agricultural field soils buried beneath the floodplain alluvium. These irrigated field soils were excavated, examined, and samples were collected for phytolith, textural, and micromorphology analyses. Micromorphology is the petrographic study of intact soils. Results from these geoarchaeological analyses indicate that field soils were fine-textured, organic-rich sediments that were saturated with water.

These micromorphology and textural samples were also compared to samples from canals and other areas on the floodplain that were not cultivated in order to understand how humans modified the floodplain sediments to create productive agricultural soils. The documentation of these anthropogenically modified floodplain soils that are at risk of erosion is important in the study of sustainable agricultural practices in arid lands.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-334058

© Copyright 2019 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.