Hector Neff

Neutron activation analysis and provenance research in archaeology

Neutron activation analysis is a powerful quantitative analytical technique with application in a broad range of disciplines such as agriculture, archaeology, geochemistry, health and human nutrition, environmental monitoring and semiconductor technology. Due to its excellent sensitivity, great accuracy and precision, and versatility, the technique is a suitable method for analysing many different types of samples. Archaeologists, in particular, have made extensive use of neutron activation analysis for the purpose of characterizing archaeological materials and determining their provenance. This paper presents a brief history of the technique and its application to archaeology, describes the physics behind the analytical method, and explains how the method is generally employed to determine the sources of archaeological materials.

A simulation approach to the problem of tempering in compositional studies of archaeological ceramics

Abstract Simulation methods are used to explore the potential for temper to confound the source attribution of chemically characterized archaeological ceramics. Addition of a given temper to two clay source-related compositional groups draws these groups together in compositional space, eventually fusing them into one group as the two mixtures approach pure temper. Although progressive coalescence of the group centroids eventually causes the groups to overlap, addition of sizeable amounts of temper may be required before any significant overlap occurs and before the stage of unresolvable overlap is reached. The tendency for groups to coalesce as temper is added is greater for more heterogeneous tempers. Overlap between tempered groups also depends on the degree of initial separation between the untempered clays and on the relationship between the composition of the clays and temper.

Instrumental Neutron Activation Analysis and Multivariate Statistics for Pottery Provenance

The application of instrumental neutron activation analysis and multivariate statistics to archaeological studies of ceramics and clays is described. A small pottery data set from the Nasca culture in southern Peru is presented for illustration.

More observations on the problem of tempering in compositional studies of archaeological ceramics

Abstract Provenance studies of archaeological ceramics by means of chemical characterization may be complicated by the presence of temper in the ceramic paste. The impact of tempering on the compositional distinctiveness of ceramics derived from two distinct clay sources defines an “overlap curve” whose shape is described by the point of maximum temper effect and spread of temper effect. Values of these parameters are determined in part by (1) relative magnitudes of elemental concentrations in clays versus tempers and (2) the initial distinctiveness of the clay sources. Demonstration of these effects with artificially generated data is presented here.

Source determination of White River Group silicates from two archaeological sites in the Great Plains

There are three known source area for WRGS (White River Group Silicates) : Flattopp Butte in northeastern Colorado, Table Mountain in east-central Wyoming, and the White River Badlands of South Dakota. The sources of WRGS in two Central Plains archaeological sites were determined using neutron-activation-analysis method. The results show that the technique has important implications for studies of prehistoric mobility and for the refinement of cultural-historical affiliation

Obsidian-Artifact Source Analysis for the Mixtequilla Region, South-Central Veracruz, Mexico

Neutron activation and statistical analyses establish source ascriptions for 201 obsidian artifacts representing Preclassic, Classic, and Postclassic period contexts in the Gulf Coast region of Mexico. Zaragoza-Oyameles, Puebla, and Pico de Orizaba, Veracruz, are the most common sources, but procurement patterns and technology shifted during the archaeological sequence. Comparative information is discussed for all periods, but especially the distribution of Zaragoza-Oyameles obsidian in the Classic period is examined. The distribution network for this obsidian served several regions. The importance of long-distance obsidian distribution for Teotihuacan is called into question.

Sourcing archaeological obsidian by an abbreviated NAA procedure

An abbreviated NAA procedure has been developed to fingerprint obsidian artifacts in the Mesoamerican region. Despite the large number of available sources, an NAA procedure, which relies on producing short-lived isotopes, has been applied with a success rate greater than 90 percent. The abbreviated NAA procedure is rapid and cost competitive with the XRF technique more often applied in obsidian sourcing. Results from the analysis of over 1,200 obsidian artifacts from throughout Mesoamerica are presented.

Evaluation of Painted Pottery from the Mesa Verde Region Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS)

For decades archaeologists have struggled with the problem of accurately determining organic and mineral-based paints in pottery from the American Southwest. Using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS), we have developed a simple and cost-effective method that permits classification of painted surfaces into mineral and organic-based categories. By applying this method to Mesa Verde and Mancos Black-on-white pottery from the Mesa Verde Region, we were able to distinguish easily between mineral and organic-based paints. Preliminary data also suggest that multiple sub-groups of mineral-based paints exist within these ceramic types, indicating that multiple recipes for manufacturing paint may have been employed by prehistoric potters from this region.

Analysis of shell-tempered pottery replicates : Implications for provenance studies

Archaeometric methods such as provenance studies must be predicated on understanding the processes that underlie the production of this information. This study focuses on element-based provenance studies of Mississippian-period pottery, which are complicated by the fact that this pottery generally was tempered with crushed shell in different amounts and of unknown species composition. Experiments conducted at the Missouri University Research Reactor (MURR) have documented elemental dilution and enhancement effects of adding shell temper to clay. Mathematical corrections previously have been employed to correct for shell-temper effects. Results of physical, chemical, and mathematical approaches to eliminating the effects of shell tempering indicate that mathematical methods, based on a firm knowledge of shell composition, provide the most efficient correction.

Smokescreens in the Provenance Investigation of Early Formative Mesoamerican Ceramics

We are glad that Sharer et al. (this issue) have dropped their original claim that the INAA data demonstrate multidirec tional movement of Early Formative pottery. Beyond this, however, they offer nothing that might enhance understanding of Early Formative ceramic circulation or inspire new insights into Early Formative cultural evolution in Mesoamerica. Instead, their response contains fresh distortions, replications of mistakes made in their PNAS articles, and lengthy pas sages that are irrelevant to the issues raised by Neff et al. (this issue). We correct and recorrect their latest distortions and misunderstandings here. Besides showing why their discussion of ceramic sourcing repeatedly misses the mark, we also correct a number of erroneous assertions about the archaeology of Olmec San Lorenzo. New evidence deepens understanding of Early Formative Mesoamerica but requires that some researchers discard cherished beliefs.