Abstract

PALACIOS-FEST, Manuel R. Late Holocene Paleoenvironmental History of the Upper West Amarillo Creek Valley at Archaeological Site 41PT185/C, Texas, USA. Bol. Soc. Geol. Mex [online]. 2010, vol.62, n.3, pp.399-463. ISSN 1405-3322.

In combination, microinvertebrates, calcareous algae (Charophyta), and the stable isotopes from ostracodes and gyrogonites (the calcareous remains of charophytes) are a powerful tool for reconstructing paleoclimates. This study compares the paleoenvironmental signatures of land and aquatic mollusks, ostracodes, and charophytes with stable-isotope (δ¹⁸O and δ¹³C) values for Cypridopsis sp. (an ostracode) and the gyrogonites of Chara globularis and Nitella flexilis. Each individual signature contributes its own evidence of environmental change between 1890 ± 40 years B.P. and post-750 ± 40 years B.P. at archaeological site 41PT185/C in northern Texas, United States of America. The interpretation of the combined data permits a detailed reconstruction of paleoclimatic variability at the transition from the Medieval Climatic Anomaly to the Little Ice Age, allowing inferences about the impact of such environmental change on human populations in this part of the U.S. Southwest.

Keywords : Microinvertebrates; gyrogonites; archaeology; paleoclimate; Medieval Climatic Anomaly; Little Ice Age.