Mineralised organic remains from cesspits at the Roman town of Silchester: processes and preservation

Rapid deterioration in buried leather: archaeological implications

Understanding archaeological leather degradation helps inform economies, crafts, and technologies of historic communities. However, archaeological leather is at high risk of degradation due to deterioration and changes within the burial conditions. This research applied non-destructive FTIR-ATR to experimentally buried vegetable-tanned leather and archaeological leather excavated at the Roman site of Vindolanda, UK to explore survival, destruction, and preservation processes of tanned leather. Analyses focused on observing and monitoring changes in chemical functional groups related to leather tannins, collagen and lipid components following burial. FTIR-ATR results highlighted rapid changes following experimental burial in wet soil, tentatively associated with early onset microbial activity, which targeted readily available lipids but not tightly bound collagen. Prior to burial, differences in structural composition were present in leather spectra based on manufacture; however, following burial in wet soil, FTIR-ATR spectra indicated de-tanning occurs rapidly, especially in waterlogged conditions, with archaeological leather becoming more uniform and similar to untanned leather. Therefore, the comparison of FTIR-ATR results from archaeological leather to experimentally buried leather samples was informative for showing the destructive de-tanning in waterlogged environments. The comparison of FTIR-ATR data from modern unburied leather cannot be compared against archaeological samples. Importantly, despite de-tanning occurring soon after burial, the vegetable-tanning method promoted long-term preservation of leather in wet soil. The observed changes could not be directly associated with the proportion of condensed to hydrolysable tannin, suggesting alternate variables impacted the preservation. Furthermore, mineral components introduced into the leather through the animal skin, tannin material and/or tannin liquid are suggested to contribute to these changes. Crucially a high degree of heterogeneity in error results within the experimentally buried sample material underlined that any changes in collagen ratios cannot be overinterpreted and must be considered within the context of larger datasets.

Food globalization in southern Central Asia: archaeobotany at Bukhara between antiquity and the Middle Ages

The Silk Road is a modern name for a globalization phenomenon that marked an extensive network of communication and exchange in the ancient world; by the turn of the second millennium AD, commercial trade linked Asia and supported the development of a string of large urban centers across Central Asia. One of the main arteries of the medieval trade routes followed the middle and lower Zarafshan River and was connected by mercantile cities, such as Samarkand and Bukhara. Bukhara developed into a flourishing urban center between the fourth and sixth centuries AD, served as the capital of the Samanid court between AD 893 and 999, and remained prosperous into the Qarakhanid period (AD 999-1220), until the Mongol invasion in AD 1220. We present the first archaeobotanical study from this ancient center of education, craft production, artistic development, and commerce. Radiocarbon dates and an archaeological chronology that has been developed for the site show that our samples cover a range between the third and eleventh centuries AD. These samples from Bukhara represent the richest systematically collected archaeobotanical assemblage thus far recovered in Central Asia. The assemblage includes spices and both annual and perennial crops, which allowed Sogdians and Samanids to feed large cities in river oases surrounded by desert and arid steppe and supported a far-reaching commercial market in the first millennium AD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12520-023-01827-z.