Duration: 2023-2024
Abstract: Amber is a fossil resin that has had a social value since the Upper Paleolithic. This is due to its unique natural characteristics, which have made it widely used and socially valued throughout prehistory, especially as a decorative and as a symbolic element. The Baltic coast and Sicily are the main natural sources of amber exploited in prehistory. Since the beginning of modern research, the presence of amber outside these regions has been used as an indicator of the existence of long-distance exchange networks (de Navarro, 1925), and consequently amber has been considered an exotic and prestigious material. On this basis, a solid tradition of research has been established to identify the origin of amber objects (Beck, 1995; Beck et al., 1965, 1964; Beck and Hartnett, 1993), which has led to the identification of spatiotemporal patterns of their consumption. The characterization of prehistoric amber ornaments has been extensively addressed in recent years (Murillo-Barroso et al., 2018; Murillo-Barroso and Martinón-Torres, 2012; Odriozola et al., 2019b), given the strong tradition of studies on this raw material of high symbolic value.
Fourier transform infrared spectroscopy (FTIR) analyses have confirmed long-distance exchange as the main form of access to amber, allowing the identification of two large-scale trends in exchange flows, starting from Sicily in the 4th-3rd millennia BC and swinging to the Baltic Sea from the 2nd millennium BC (Odriozola et al., 2019b). Despite this exogenous trend, in the last decades the focus has also been put on the geological deposits of Iberian amber, with the documentation of different local sources of amber on the Cantabrian coast (Álvarez Fernández et al., 2005; Murillo-Barroso et al., 2018). On the other hand, numerous local amber outcrops remain to be characterized, such as those between the Tagus and Mondego estuaries in Portugal (Peñalver et al., 2018). Despite the acknowledged long-distance exchange of Baltic and Sicilian amber, and the lack of a comprehensive spectral record of Portuguese amber, scientists have recently suggested that Sicilian and Portuguese amber have similar spectral characteristics, compromising origin identification. Consuming local instead of foreign amber would therefore completely change the image of a united Europe.
IberAmber is a project conceived and designed in a multidisciplinary way, using chemical-analytical techniques, classical statistical methods, and more modern approaches such as machine learning to deepen the archaeological knowledge of amber trade and exchange.The principal objectives are to locate amber deposits; To characterize the amber deposits by means of FTIR, GC-MS and 13C-MAS-NMR in order to obtain more detailed information about the chemical composition of the deposits, the aging processes and the botanical origin of the amber; To create a reference spectral library of Portuguese amber;To generate a classification tool by supervised statistical analysis of geological amber;To provide a web application that predicts the origin of archaeological amber artifacts through their FTIR signatures.
In order to create a library of standardized reference spectra for each deposit, IberAmber aims to locate and chemically characterize the Portuguese amber deposits. The standardized reference spectra of the amber deposits will then be used as a fingerprint of the Portuguese amber deposits. These, in turn, will later be compared with the spectra of archaeological artifacts to determine their origin.
Coordinator: Carlos P. Odriozola Lloret
Participants: José Eduardo de Oliveira (FCUL) ; Ana Catarina Sousa (UNIARQ/FLUL); João Daniel Casal duarte (FCUL); José María Martínez Blanes (Universidade de Sevilha);José Ángel Garrido Cordero (UNIARQ/FLUL);
Daniel Sánchez Gómez (UNIARQ/FLUL); Maria Dolores Zambrana Vega (Universidade de Sevilha); Jose Luis Molina Gonzalez (Universidade de Sevilha); Victor S. Gonçalves (UNIARQ/FLUL); Cátia Delicado (UNIARQ/FLUL, CIAS/FLUC)
André Texugo (UNIARQ/FLUL, CEG) e Daniel van Calker (UNIARQ/FLUL).
Partner institutions: Universidade de Sevilha e a Faculdade de Letras da Universidade de Lisboa
Financial support: Fundação para a Ciência e a Tecnologia
Reference: 2022.09207.PTDC