Radiocarbon Samples and Archaeological Excavation: a Commentary Based on the "Valdivia Absolute Chronology"

Summary

The cultural chronology of Ecuador is based on several hundreds radiocarbon determinations. Most of the dated samples, which come from coastal sites, are charcoal, however a good number were shell and few were the collagen of human bone. Some dates were obtained by other methods. Early in the fifties, obsidian hydration dates served to complete the 14C sequence, and more recent Thermoluminescence assays have not only completed some missing dates for a more refined sequence, but have served to validate some 14C calibrations and to explain some aberrant determinations. In the following commentary, we will refer mostly to Valdivia dates, since they were obtained by the most varied field methods, during the forty years Valdivia sites have been under excavation.

This paper has two parts: firstly, an archaeological discussion of the Valdivia absolute chronology by Jorge Marcos; and secondly, the presentation of the calibration of the Valdivia dates in the Gliwice Radiocarbon Laboratory, by Adam Michczynski. Marcos, discusses the importance of selecting a 14C sample in order to obtain a secure date, and the most common errors that have affected the Valdivia absolute chronology. The necessity to calibrate dates, and the importance of publishing them properly. (1)

The results of calibration of individual 14C dates by Adam Michczynski are presented in Table 1 and Figure 1. Finally, as a corollary, a commentary on the problems presented in the combined presentations is provided by the senior author.

Summary

This paper is intended to consider a problem of possibility of applying the C-14 method application to establish the Inca state chronology. We attempted to find out the time intervals of Inca Imperial Phase and Inca Preimperial Phase and to make rough estimation of time intervals corresponding to periods, when succeeding rulers of The Inca Empire reigned. To this end we applied the composite probability distribution of calibrated radiocarbon dates. Obtained results seems to confirm time intervals established basing on the chronicles.

Publicado originalmente en 1994 en versión inglesa: Ziólkowski et. al 1994

Es evidente que la base de toda investigación arqueológica es establecer la cronología (relativa y absoluta) del fenómeno analizado. En arqueología andina, la datación absoluta se realiza principalmente por el método de datación C-14, y las fechas de los sitios arqueológicos andinos aparecieron en las primeras listas de laboratorio de radiocarbono, a principios de los años cincuenta, es decir, hace más de 40 años. Ciertamente, los métodos termoluminiscente, paleomagnético y de obsidiana se utilizan con mucha menos frecuencia. Desafortunadamente, a pesar de un avance muy destacado en la exploración de las culturas prehispánicas, y del hecho mencionado anteriormente de la aplicación muy temprana del método C-14 en la arqueología andina, la cronología absoluta de esta región sigue siendo objeto de muchas controversias.