CSIC analyzes gold composition of pre-Columbian treasure

December 12, 2011

An international project including CSIC, in collaboration with the Museo de America in Madrid, is studying a set of pre-Columbian metallurgic pieces with the latest advances in observational and non-destructive analysis techniques. The initiative aims to have an in-depth knowledge of the processes of making, assembly and usage of nearly 200 pieces from Costa Rica and the archeological complex known as "Quimbaya Treasure," from Colombia.

For this purpose, the objects have been moved from the museum, to two laboratories, where they will be examined with the aid of ion beams generated in a particle accelerator, among other techniques.

CSIC researcher Alicia Perea, explains: "The project's objective is the study of gold, silver and copper alloys, known as tombacs, and their connection to the socio-economic processes of transmission, innovation and technological change in this historical period. In some parts of America, metallurgy of gold had reached levels of technical and artistic excellence, but there is still much research to do on the procedures used".

Archaeometric study

The study of the metallurgic complex will focus on the characterization of objects by means of several observational and non-destructive analysis techniques, such as scanning electron microscopy (SEM-EDS), X-ray fluorescence (XRF) or ion beams techniques (IBA) generated in a particle accelerator. Thus, the experts' team will try to determine the processes of making, assembly and usage of the pieces, as well as the deterioration that may had suffered at the site. Perea adds: "The idea is to make the latest technology available to the service of historical heritage study".

The treasure analysis is being conducted in two research centers. The first, in the Electron Microscopy and Microanalysis Laboratory of CSIC Human and Social Sciences Center, provided with specific technology for energy dispersive microanalysis. The second, in the Center for Microanalysis of Materials of the Universidad Autónoma de Madrid, since it has a particle accelerator specifically designed for archeological or artistic objects.

The Central Bank Museums Foundation of Costa Rica and the Physics Institute of UNAM (National Autonomous University of Mexico) have also participated in the study, which will last three years.

The Quimbaya civilization

The term "Quimbaya" refers to the tribes that occupied the middle Cauca river basin, at the current Colombian Coffee-Growers Axis, around the 16th century, when the Spanish Conquest took place. The same term is used to define the two historical periods of metallurgic production in this region: the Early Quimbaya (between 500 BC and 600 AD) and the Late Quimbaya (until around 1600). CSIC researcher states: "We use the same term despite not being able to establish a line of ethnic continuity between the Quimbaya people of the conquest period and the historical settlement that made gold work their most refined and complex artistic expression".

Perea adds: "These tribes, whose economy was based on agriculture, were organized into small groups of about 200 people. They were led by a chief or cacique, responsible for the redistribution of wealth. The cacique accumulated treasures, expressing his range, and exhibited them to his people. Metallurgy, especially metallurgy of gold, was a technology associated with power".

The most charismatic objects of their metallurgic production are anthropomorphic recipients, where they mixed coca leaf and lime for ceremonial use. The figures depict the images of men and women in ecstatic trance. The researcher concludes: "These same recipients were also used as funerary urns to store the ashes of dead people in burial grounds. Throughout history, these sites have been systematically looted by looters and the pieces have been scattered through antique market".

The set of objects to analyze in this study was found in 1891 and makes up part of two grave goods from Quindio Department, in Colombia. The president of the Republic of Colombia, Carlos Holguín, bought this set in order to present it in the 4th Centenary of the Discovery of America Exhibition in 1892, in Madrid. Eventually, it was donated to the Queen Regent of Spain, María Cristina de Habsburgo y Lorena, in appreciation of her mediation in a border dispute with Venezuela. Currently, the collection belongs to the Museo de América, located in Madrid.

Spanish National Research Council (CSIC)

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