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1. New light on the use of Theobroma cacao by Late Classic Maya

   https://doi.org/10.1073/pnas.2121821119  

   Ford, Anabel; Williams, Ann; de Vries, Mattanjah S. (October 2022, Proceedings of the National Academy of Sciences)

   Cacao seeds, Theobroma cacao , provide the basis for a ceremonially important Mesoamerican food. Past efforts to identify cacao in ceramics focused on highly decorative vessel forms associated with elite ceremonial contexts, creating assumptions as to how cacao was distributed and who could access it. This study examines 54 archaeological ceramic sherds from El Pilar (Belize/Guatemala) of Late Classic (600 to 900 CE) residential and civic contexts representing a cross-section of ancient Maya inhabitants. Identification of cacao in ancient sherds has depended on the general presence of theobromine; we used the discrete presence of theophylline, a unique key biomarker for cacao in the region. Analysis was done by grinding off all outside surfaces to reduce contamination, pulverizing the inner clay matrix, extracting absorbed molecules, and concentrating the extractions. In order to obtain especially high selectivity and low limits of detection, our study utilized the technique of resonance-enhanced multiphoton ionization coupled with laser-desorption jet-cooling mass spectrometry. This technique isolates molecules in the cold gas phase where they can be selectively ionized through a resonant two-photon process. Of the sherds analyzed, 30 samples (56%) were found to contain significant amounts of theophylline and thus test positive for cacao. Importantly, cacao is present in all contexts, common to all Maya residents near and far from centers. 

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2. Pottery production and Granular White imports at Late Formative San José Cuautitlan

   https://doi.org/10.1111/arcm.70014  

   Stoner, Wesley D; Hernández_Sariñana, Daniela (July 2025, Archaeometry)

   Abstract This study centers on a sample of ceramics (n = 37) from the site of San José Cuautitlan and contextualized within a much larger database of Formative ceramics (n = 1242), mostly from greater central Mexico. The sample was assayed through neutron activation analysis (NAA), with a subsample made into thin sections for petrographic analysis. In this article, we (1) situate the sample from San José within the longer history of ceramic traditions over the Formative period in the Basin of Mexico, (2) assess the pottery production recipe employed at San José in comparison to the composition of ceramics from neighboring segments of the Basin, and (3) source a sample of 10 Granular White amphora that were imported into the site. We demonstrate a low level of ceramic trade among sites within the Basin of Mexico. We also tentatively source Granular White amphora recovered at the site to central Morelos. Further, we show through a comparison of these Late Formative Granular White specimens to later Classic period Granular Ware from Teotihuacan and other sites that the source of this trade ware changed over time. 

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3. Unveiling the distinctive geochemical signature of fine ware through Sr–Nd–Pb isotopes: A site‐specific perspective from the site of Cales (South Italy)

   https://doi.org/10.1002/gea.22021  

   Verde, Maria; De_Bonis, Alberto; D'Antonio, Massimo; Renson, Virginie; Czujko, Stephen; Tomeo, Antonella; Morra, Vincenzo (January 2025, Geoarchaeology)

   Abstract This study explores the use of three isotopic systematics—Sr, Nd, and Pb— combined together for the first time to trace the origins of ancient pottery. This approach strengthens our ability to relate raw materials to the final products. The materials selected for the analysis are from a well‐documented data set, previously subjected to a thorough mineralogical–petrographic and chemical characterization. Seventeen ceramic specimens represented by black‐glazed pottery, Terra sigillata, and fine common ware as well as production indicators such as black‐glazed pottery wasters and spacers were examined via isotope analyses. These samples were discovered in the archaeological site of Cales, presently Calvi Risorta, in South Italy. CaO‐rich clay raw materials from the area of interest were also analyzed as comparative references for the investigated ceramics. The comparison of the archaeometric data of the ceramic samples with the clay raw materials showed an affinity between the ceramics studied and local clay raw materials belonging to Mio‐Pliocene marine sediments from the Campania Apennine Mountain area. This affinity was more accurately defined through the Sr, Nd, and Pb isotopes, which show coinciding signatures among ceramic samples, production indicators, and raw materials. The method yields promising outcomes that reinforce prior experimental investigations and amplify its reliability. The multi‐isotopic methodology highlights the significance of combining geochemical data to pinpoint the origins of raw materials used for ancient ceramic production. 

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4. Neutron Activation Analysis Reveals Jamaican Origin of Afro-Caribbean Ware Excavated from the Cayman Islands

   https://doi.org/10.1007/s10761-024-00752-8  

   Petras, Elysia_M; MacDonald, Brandi_L (August 2024, International Journal of Historical Archaeology)

   Abstract Afro-Caribbean ware is Caribbean-made pottery manufactured both at the craft and industrial scale by enslaved and free potters of African descent. Previous sourcing studies have shown historic variation in centers of production and market distribution of these wares across the Caribbean. We used Neutron Activation Analysis (NAA) on a clay sample and 13 low-fired coarse earthenware sherds excavated from the historic-period Jackson Wall Manor site on Grand Cayman. We found that the Grand Cayman clay was compositionally inconsistent with any previously analysed ceramic sherds in the University of Missouri Research Reactor (MURR) NAA Caribbean database, and that the ceramic samples excavated on Grand Cayman showed high statistical correlation with Jamaican ceramic groups. These findings suggest that coarse earthenware on Grand Cayman was transported from Jamaica, a nearby colony with established potteries and markets, rather than being produced locally. Jamaican yabbas, which combined African and European manufacturing technique and forms, were imported into Grand Cayman to fit local needs. 

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5. Geochemical Variability Along the Northern East Pacific Rise: Coincident Source Composition and Ridge Segmentation

   https://doi.org/10.1029/2019GC008287  

   Mallick, Soumen; Salters, Vincent J. M.; Langmuir, Charles H. (April 2019, Geochemistry, Geophysics, Geosystems)

   Abstract New trace element abundances and isotope compositions for more than 100 mid‐ocean ridge basalts from 5.5°N to 19°N on the East Pacific Rise show step function variations in isotopic composition along the ridge axis that coincide with ridge discontinuities. Transform faults, overlapping spreading centers, and devals (deviation from axial linearity) mark the separation of individual clusters of distinct isotopic composition and trace element ratios that indicate source variations. This correlated chemical clustering and morphological segmentation indicates that source composition and segmentation can be closely related even on a fine scale. Substantial chemical variations within a segment are related to source composition. This suggests that even within segments the magma transport is mainly vertical, and there is limited along‐ridge transport, and there is little evidence for magma chambers that are well mixed along strike. Trace element concentrations show good correlations with isotopic compositions on a segment scale but less so on a regional scale. The trace element and isotopic variability along the northern East Pacific Rise can be explained by three mantle components: a depleted peridotite endmember, an enriched peridotite endmember, and a recycled gabbro‐like component. The gabbroic component has an isotopic signature indicating an ancient origin. The high‐resolution sampling indicates that within a segment the chemical variability is largely binary but that the endmembers of the binary mixing change from segment to segment. The endmembers of the binary variation within a segment are a combination of three of the endmembers. 

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