Geochemical fingerprinting of Monegros cherts: Redefining the origin of a prehistoric tracer

Abstract

The geographical name of Monegros has traditionally been used to describe a high-quality, dark-coloured chert originating in a carbonate lacustrine environment, being one of the most important long-distance tracers in south-west Europe during prehistory. This chert type outcrops in the Monegros region, situated in the Ebro Basin (north-eastern Iberia), but not only there, as cherts with the same descriptions are found in other regions, some far from the homonymous area. Nevertheless, prehistorians working on the characterization of lithic sources have frequently used the term 'Monegros' to define this chert, basing their attributions solely on macroscopic descriptions. These are not sufficient as they do not allow cherts from the Monegros region to be distinguished from cherts from other regions. In this study, the area where Monegros cherts outcrop was delimited and fieldwork was carried out to identify the origin of the geological formations and the preserved outcrops. The classic approach has proved to be insufficient for this purpose, so geochemical fingerprinting using energydispersive X-ray fluorescence (ED-XRF) spectroscopy was performed. The results obtained after this first geochemical approach show that some differences can be found between the different formations in the Monegros region in terms of their major and minor components.

Lithic raw material procurement at the Chaves cave (Huesca, Spain): A geochemical approach to defining Palaeolithic human mobility

“…Seven geological formations outcropping in the Ebro Basin and the Pre‐Pyrenean region possess identical features at the macroscopic and petrographic scale (Castelltallat Formation—Rupelian, Oligocene–, Tremp Fm—Maastrichtian, Upper Cretaceous–, Tartareu‐Alberola unit—Oligocene–, Bujaraloz‐Sariñena unit—Agenian–Aragonian, Miocene–, Torrente de Cinca‐Alcolea de Cinca unit—Chattian–Agenian, Miocene–Oligocene–, Lanaja‐Castejón unit—Upper Aragonian, Miocene– and Sierra de Pallaruelo‐Monte de la Sora unit—Lower Aragonian, Miocene–). All of these geological formations possess chert outcrops with identical macroscopic and petrographic features as the presented in type 1 cherts, with Charophyte algae and gastropods as the main biological content and a microquartz mosaic fabric as the main silica texture observed at the microscopical scale (García‐Simón, 2018; Sánchez De la Torre, García‐Simón, 2019; Sánchez de la Torre, Le Bourdonnec, Gratuze, Domingo, et al, 2017).…”

“…They possess similar macroscopic and petrographic features to cherts from seven geological formations outcropping in the Ebro Basin (Bujaraloz‐Sariñena unit—Agenian–Aragonian, Miocene–, Torrente de Cinca‐Alcolea de Cinca unit—Chattian–Agenian, Miocene–Oligocene–, Sierra de Lanaja‐Montes de Castejón unit—Upper Aragonian, Miocene– and Sierra de Pallaruelo‐Monte de la Sora unit—Lower Aragonian, Miocene–) and the contact area between the Ebro Basin and the Pre‐Pyrenees (Castelltallat formation—Rupelian, Oligocene– and Tartareu‐Alberola unit—Oligocene–). In this case, ED‐XRF data has already given valuable information to distinguish between the geological formations and thus directly connect some of the archaeological samples (Sánchez De la Torre, García‐Simón, et al, 2019; Sánchez de la Torre, Le Bourdonnec, Gratuze, Domingo, et al, 2017). With the data obtained, median values of each geological outcrop were calculated and a Principal Component Analysis (PCA) was run to see if quantified distinctions were visible at the major and minor elemental levels.…”

“…With the aim of comparing results obtained after the analysis of archaeological remains, geological formations with cherts outcropping in NE Iberia and specifically in the Pyrenean region and the nearby Ebro Basin have been surveyed, sampled and studied during recent years (García‐Simón, 2018; Sánchez de la Torre, 2015; Sánchez de la Torre, Le Bourdonnec, Dubernet, et al, 2017; Sánchez de la Torre & Mangado, 2016; Sánchez De la Torre, García‐Simón, Le Bourdonnec, & Domingo, 2019; Sánchez de la Torre, Le Bourdonnec, & Gratuze, 2019; Sánchez de la Torre, Mangado, & Fullola, 2017). As these studies have already been partially or totally published, in this paper, we do not provide a complete description of each geological formation and their characteristics in‐depth.…”

Characterizing the lithic raw materials from Fuente del Trucho (Asque‐Colungo, Huesca): New data about Palaeolithic human mobility in north‐east Iberia

“…With the aim of comparing the results obtained after the analysis of archaeological remains, geological formations with cherts outcropping in north‐east Iberia, and specifically in the Pyrenean region and the Ebro Depression, were surveyed, sampled and studied in recent years (Sánchez de la Torre and Mangado 2016; Sánchez de la Torre et al . 2017b, 2019a, 2019b). In this study, the archaeological lithological groups from Fuente del Trucho were compared with 11 geological formations possessing similar characteristics and outcropping in the Ebro Depression and the Pyrenean mountain range, in sum there being almost 20 different outcrops selected for study.…”

El aprovechamiento histórico del sílex para piedras de fusil. El caso del río Huerva (Zaragoza)

“…Entre ellas cabe destacar algunos sectores del valle medio del Ebro, con importantes recursos silíceos que fueron aprovechados desde la Prehistoria. Los estudios arqueológicos desarrollados durante el s. xx e inicios del xxi nos ilustran sobre ello (Bardaviu, 1923;Maluquer, 1955;Vallespí, 1959;Álvarez, 1985;Barandiarán y Cava, 1985;Picazo, 1986;Utrilla y Tilo, 1991;Cabello, 2005;Domingo, 2006…), y más recientemente ha habido interesantes aportaciones relacionadas con la caracterización y distribución del tipo de sílex denominado 'Botorrita' (Leorza, 2013) o 'Monegros' Sánchez et al, 2019) e incluso con la identificación de un nuevo complejo minero neolítico (Picazo et al, 2018;.…”