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IntCal, SHCal, or a Mixed Curve? Choosing a 14C Calibration Curve for Archaeological and Paleoenvironmental Records from Tropical South America

Published online by Cambridge University Press:  16 March 2018

Erik J Marsh Open the ORCID record for Erik J Marsh [Opens in a new window] ,
Maria C Bruno ,
Sherilyn C Fritz ,
Paul Baker ,
José M Capriles  and
Christine A Hastorf
Erik J Marsh*
Affiliation:
CONICET, Laboratorio de Paleo-Ecología Humana, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, 5500, Argentina
Maria C Bruno
Affiliation:
Dickinson College, Department of Anthropology & Archaeology, PO Box 1773, Carlisle, PA 17013, USA
Sherilyn C Fritz
Affiliation:
Department of Earth and Atmospheric Sciences and School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE 68588-0340, USA; and Department of Geology, Lund University, Lund SE-223 62, Sweden
Paul Baker
Affiliation:
Division of Earth and Ocean Sciences, Duke University, Durham, NC 27708, USA
José M Capriles
Affiliation:
Department of Anthropology, Pennsylvania State University, University Park, PA 16802, USA
Christine A Hastorf
Affiliation:
Department of Anthropology, University of California, Berkeley, 232 Kroeber Hall, Berkeley, CA 94720, USA
*
*Corresponding author. Email: erik.marsh@gmail.com.
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Abstract

Because the 14C calibration curves IntCal and SHCal are based on data from temperate latitudes, it remains unclear which curve is more suitable for archaeological and paleoenvironmental records from tropical South America. A review of climate dynamics reveals a significant influx of Northern Hemisphere air masses and moisture over a substantial part of the continent during the South American Summer Monsoon (SASM). Areas affected by the SASM receive unknown amounts of input from both hemispheres, where an argument could be made for either curve. Until localized tree-ring data can resolve this, we suggest using a mixed calibration curve, which accounts for inputs from both hemispheres, as a third calibration option. We present a calibration example from a crucial period of environmental and cultural change in the southern Lake Titicaca. Given our current lack of data on past ∆14C variation in South America, our calibrations and chronologies will likely change in the future. We hope this paper spurs new research into this topic and encourages researchers to make an informed and explicit choice of which curve to use, which is particularly relevant in research on past human–environmental relationships.

Keywords

14C calibration curveshemispheric variation in atmospheric 14CIntertropical Convergence Zonemixed curve calibrationSouth American Summer Monsoon
Type
Research Article
Information
Radiocarbon , Volume 60 , Issue 3 , June 2018 , pp. 925 - 940
Copyright
© 2018 by the Arizona Board of Regents on behalf of the University of Arizona 

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