Distinguishing between calcites formed by different mechanisms using infrared spectrometry: archaeological applications

Infrared spectrometry is a well-established method for the identification of minerals. Due to its simplicity and the short time required to obtain a result, it can be practiced on-site during excavation using portable infrared spectrometers. However, the identification of a mineral may not be sufficient. For example, a lime plaster floor and a crushed chalk surface have a similar appearance and are composed of the same mineral – calcite. Here we exploit differences in the infrared spectra of geogenic, biogenic and pyrogenic calcites for the identification of each calcite type. The infrared calcite spectrum has three characteristic peaks in the region of 400–4000 cm⁻¹, designated ν₂, ν₃, and ν₄. When a calcite sample is ground, as part of the measurement preparation procedure, some grinding dependent changes will be revealed in the infrared spectrum. With additional grinding, the ν₃ peak narrows and the heights of the ν₂ and ν₄ peaks decrease, when both are normalized to the ν₃ height. By plotting the normalized heights of the ν₂versus the ν₄ of several grindings of the same sample, a characteristic trend line is formed for each calcite type. The trend lines of geogenic calcites have the shallowest slopes and highest ν₄ values when compared to pyrogenic calcites, which can be further divided to ash and plaster/mortar samples. This method can assist in distinguishing between the various calcites, and provide insights into homogeneity and preservation state of the calcitic materials in question.     

Does size matter: the role and significance of cereal grains in the Indus civilization

Cereal grains play a pivotal role in the rise and character of the Indus civilization. Archaeologists have traditionally focused their attention on the large-grained crops of wheat and barley while often minimizing the importance of the smaller-grained millets. Both environmental and cultural variables influence crop selection in the past as well as today. This paper explores the role and significance of cereal grain size during the evolution of the Indus civilization.     

Recovery of DNA from archaeological insect remains: first results,problems and potential

We report the recovery of short fragments of PCR amplifiable ancient DNA from exoskeletal fragments of the grain weevil Sitophilus granarius (L.) extracted from Roman and medieval deposits in Northern England. If DNA preservation in archaeological insect remains is widespread then many applications in the spheres of evolutionary studies and archaeology can be conceived, some of which are outlined.     

Building a tephrostratigraphic framework for the Paleolithic of Central Anatolia,Turkey

The Central Anatolian Volcanic Province (CAVP) in Turkey preserves widespread deposits of Quaternary tephra, presently associated with a small but growing number of Paleolithic archaeological sites. We use multivariate analyses of the abundances of a suite of nine major and minor element oxides determined by electron probe microanalysis. From these data, we construct a classificatory model for correlating distal tephra to one of five volcanic edifices or eruptive phases within the CAVP. Application of this model to distal deposits of primary tephra-fall and reworked tuffaceous sediments from the archaeological sites of Körkuyu and Kaletepe Deresi 3 indicates Late to possibly Early Pleistocene ages for the artifact assemblages there, and provides a fundamental tephrostratigraphic framework to examine spatial and temporal variation in hominin behavior comparable to that of other regions, such as eastern Africa.     

A biometric technique for assessing prehistoric freshwater mussel population dynamics (family: Unionidae) in north Texas

Biometry is useful for a suite of analyses relevant to zooarchaeology, which include analysis of mortality profiles, taphonomy, paleoecology, among other purposes. Here, size-age prediction models are developed for 10 freshwater mussel species found in north Texas to develop a method for studying paleoenvironmental conditions. Shell length is often used to evaluate the structures of modern mussel populations, but its use on paleozoological specimens is not feasible because complete shells rarely preserve. Instead, pallial line-to-lateral teeth length (PLL) and pseudocardinal teeth-to-pallial line length (PSP) are evaluated as proxy measures for shell length. Linear regression models based on PLL and PSP using modern mussels demonstrate that they are accurate proxies of shell length for multiple species from a variety of habitats. In addition, ontogenetic-age structures for a modern sample and for two late Holocene assemblages from north Texas are developed using PLL and PSP. These techniques are useful tools for evaluating past ecological conditions of freshwater mussel populations when large samples are available for study, which expands analytical potential of zooarchaeological studies of prehistoric unionid remains.