Provenance study of the variscite artifacts of the Sierra Nevada de Santa Marta, Colombia and approach to routes of pre-Hispanic exchange

Acevedo, Natalia Millán; Weber, Marion; Proenza, Joaquín A.; Garcia‐Casco, Antonio; Sáenz-Samper, Juanita

doi:10.1016/j.jas.2021.105511

Cited by 6 publications

(3 citation statements)

References 10 publications

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“…The cultural taste for specific raw materials with particular characteristics such as lustre, texture or green colour is not a particular phenomenon of the western Mediterranean. Other areas such as the south-west of the United States, Mexico, Colombia and the Caribbean present similar cases involving raw materials such as jade, variscite and turquoise [ 13 , 49 , 50 ]. The approach proposed in this study, (the combination of analytical techniques such as p-XRF +XRD) to acquire quality data to build supervised models with reliable predictive capacity has a great potential to include new classes such as Jade or lapislazuli and contribute to addressing questions related to the consumption of this type of objects in a wide cultural and geographical range.…”

Section: Resultsmentioning

confidence: 99%

A supervised multiclass framework for mineral classification of Iberian beads

Sanchez-Gomez,

Odriozola Lloret,

Sousa

et al. 2024

PLoS ONE

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Research on personal adornments depends on the reliable characterisation of materials to trace provenance and model complex social networks. However, many analytical techniques require the transfer of materials from the museum to the laboratory, involving high insurance costs and limiting the number of items that can be analysed, making the process of empirical data collection a complicated, expensive and time-consuming routine. In this study, we compiled the largest geochemical dataset of Iberian personal adornments (n = 1243 samples) by coupling X-ray fluorescence compositional data with their respective X-ray diffraction mineral labels. This allowed us to develop a machine learning-based framework for the prediction of bead-forming minerals by training and benchmarking 13 of the most widely used supervised algorithms. As a proof of concept, we developed a multiclass model and evaluated its performance on two assemblages from different Portuguese sites with current mineralogical characterisation: Cova das Lapas (n = 15 samples) and Gruta da Marmota (n = 10 samples). Our results showed that decisión-tres based classifiers outperformed other classification logics given the discriminative importance of some chemical elements in determining the mineral phase, which fits particularly well with the decision-making process of this type of model. The comparison of results between the different validation sets and the proof-of-concept has highlighted the risk of using synthetic data to handle imbalance and the main limitation of the framework: its restrictive class system. We conclude that the presented approach can successfully assist in the mineral classification workflow when specific analyses are not available, saving time and allowing a transparent and straightforward assessment of model predictions. Furthermore, we propose a workflow for the interpretation of predictions using the model outputs as compound responses enabling an uncertainty reduction approach currently used by our team. The Python-based framework is packaged in a public repository and includes all the necessary resources for its reusability without the need for any installation.

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Section: Resultsmentioning

confidence: 99%

A supervised multiclass framework for mineral classification of Iberian beads

Sanchez-Gomez,

Odriozola Lloret,

Sousa

et al. 2024

PLoS ONE

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“…Unlike colonial glass beads (Scaramelli and Tarble de Scaramelli 2005), quiripa beads have not been recorded in the Middle Orinoco. Contrary to the numerous shell ornaments from the north-central and Caribbean coast in Venezuela (Guzzo et al 2017) and the Tairona variscite beads (Acevedo et al 2021) found along the Caribbean, rare quiripa-like shell beads only appear in funerary contexts in the Venezuelan Andean and sub-Andean areas (Gassón 2000:586). There is no archaeological evidence for shell bead exchange up the Orinoco River, despite the mention of their trade in ethnohistorical records.…”

Section: Traces Of Trade and Exchange In The Archaeological Recordmentioning

confidence: 99%

Beads and Stamps in the Middle Orinoco: Archaeological Evidence for Interaction and Exchange in the Atures Rapids from AD 1000 to 1480

2022

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The area of the Atures Rapids in the Middle Orinoco River (Venezuela), where multiple Indigenous communities gathered to trade goods, has been identified as a prominent center of commerce since early colonial times. However, the exchange activities taking place there between local and nonlocal actors before European colonization are poorly understood, based only on the ethnohistoric record. This article presents an archaeometric analysis of stone beads and ceramic roller stamps, items previously associated with trade practices, from two recently excavated sites in the region, Picure (AD 1030–1480) and Rabo de Cochino (AD 1000–1440); it assesses their provenance, production, and value. We propose that Picure was a site of a bead-manufacturing workshop and a place where roller stamps were exchanged. The stamps were acquired and produced by different potting groups. Analysis of the chaîne opératoire and production techniques shows processes of adaptation and emulation associated with the multiple, multiethnic communities during the period from AD 1000 to 1480. Both beads and stamps are linked to identity regalia that were likely used as part of ceremonies taking place in the area of the Rapids, as indicated by the numerous and monumental petroglyphs found on the islands.

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“…Significant examples of these prehistorical uses of variscite have been reported in northern Portugal [10], France [11], and Spain [12][13][14][15]. In fact, variscite was also mined during pre-Hispanic times in South America [16,17] and more recently in North America [18] and Australia [19].…”

Section: Introductionmentioning

confidence: 99%

Colours of Gemmy Phosphates from the Gavà Neolithic Mines (Catalonia, Spain): Origin and Archaeological Significance

et al. 2022

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In the Neolithic Gavà mines, variscite and turquoise were exploited for ornaments manufacturing, although some prospective pits and tunnels were dug on other similar greenish minerals such as smectite or kandite. A 3D study of the distribution of mineral phases allows us to determine the parameters involved in variscite colours. Methods are comprised of quantitative colourimetry, thin section petrography, SEM-BSE-EDS, EMPA, XRD, Raman spectroscopy, and 57Fe Mössbauer spectrometry. Mapping of the mines indicates that colour is not directly dependent on depth. Although variscite from Gavà is poor in Cr3+ and V+3 compared with gemmy variscite from other localities, the deep green samples content has the highest values of Cr3+. In the case of cryptocrystalline mixtures with jarosite, phosphosiderite, or goethite, variscite tends to acquire a greenish brown to olivaceous hue. If white minerals such as quartz, kandite, crandallite, or alunite are involved in the mixtures, variscite and turquoise colours become paler.

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Provenance study of the variscite artifacts of the Sierra Nevada de Santa Marta, Colombia and approach to routes of pre-Hispanic exchange

Cited by 6 publications

References 10 publications

A supervised multiclass framework for mineral classification of Iberian beads

A supervised multiclass framework for mineral classification of Iberian beads

Beads and Stamps in the Middle Orinoco: Archaeological Evidence for Interaction and Exchange in the Atures Rapids from AD 1000 to 1480

Colours of Gemmy Phosphates from the Gavà Neolithic Mines (Catalonia, Spain): Origin and Archaeological Significance

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