Basalt Celts: Exploration of Pre-Columbian Basalt Tools in the Gulf of Fonseca &amp; Throughout Mesoamerica with XRF

A collection of hardstone/basalt artefacts from the celt-making industry was gathered from excavations at the Postclassic pre-Columbian sites of La Tigüilotada and Gualorita on El Tigre Island in the Gulf of Fonseca. In an attempt to understand the poorly researched basalt industry in the pre-historic Gulf of Fonseca, the artefacts were analysed to determine if La Tigüilotada and Gualorita procured basalt from singular or multiple sources. A literature review was conducted to understand the use, procurement, circulation, and exchange of basalt tools and raw materials throughout Mesoamerica; it was determined that all sites used advanced trade routes to acquire basalt from multiple local and non-local sources. From the Early Formative period to the Historic period, substantial basalt industries with complex exchange networks existed throughout Mesoamerica. All objects (n=115) were inventoried, classified, and macroscopically examined for variations in their matrix; potential rock...Show moreA collection of hardstone/basalt artefacts from the celt-making industry was gathered from excavations at the Postclassic pre-Columbian sites of La Tigüilotada and Gualorita on El Tigre Island in the Gulf of Fonseca. In an attempt to understand the poorly researched basalt industry in the pre-historic Gulf of Fonseca, the artefacts were analysed to determine if La Tigüilotada and Gualorita procured basalt from singular or multiple sources. A literature review was conducted to understand the use, procurement, circulation, and exchange of basalt tools and raw materials throughout Mesoamerica; it was determined that all sites used advanced trade routes to acquire basalt from multiple local and non-local sources. From the Early Formative period to the Historic period, substantial basalt industries with complex exchange networks existed throughout Mesoamerica. All objects (n=115) were inventoried, classified, and macroscopically examined for variations in their matrix; potential rock species were identified in the macroscopic analysis with the intent to be verified by the XRF results. In the classification chapter, the artefacts were classified into 7 categories of artefact types and 11 visually distinct matrices. This project aimed to determine the validity of using XRF to analyse basalts and distinguish different provenances. One object from each context (n=44) was tested using pXRF analysis to gather the bulk compositions of the artefacts in the assemblage; the XRF results were made into a database. The XRF results were interpreted by implementing the data into bivariate plots to examine potential provenance clusters. Elements Mg, Al, Si, Ti, Fe, K, Ca, Sr, Y, and Zr were plotted against each other to identify group variations. The XRF analysis could not accurately record light elements Mg, Al, and Si and was consequently unable to verify the species determinations from the macroscopic analysis. However, XRF analysis successfully established three main provenances in addition to 9 outliers that were also interpreted as unique provenances. The majority of the assemblage consisted of a fine-grained blue-grey stone; the three main provenance groups and two outliers were completely comprised of this matrix type, suggesting five unique provenances for this type of material. All completed celts were foreign to El Tigre; one provenance group was comprised solely of completed celts. The other two groups exhibited no completed celts but were made of many celt production implements with similar chemical compositions; these materials were noted to likely be local to El Tigre. La Tigüilotada was determined to be a preform production site and part of a wider network of basalt exchange which should now be studied. Gualorita’s basalt industry is connected to La Tigüilotada but remains uninterpreted. This project offers an opportunity for future studies to identify the species of rock and the true sources of these artefacts.Show less

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Basalt Celts: Exploration of Pre-Columbian Basalt Tools in the Gulf of Fonseca & Throughout Mesoamerica with XRF