YRA Seminar Series

New Seminar Series

We are happy to announce a new Seminar Series with monthly presentations highlighting exciting research of ECRs!
Each month, we will host an online 1-hour meeting, with about 30 minutes presentations followed by a discussion on the topic. ECRs from around the globe will be invited to present diverse topics, reflecting the multidisciplinary character of archaeological sciences. We aim to have these talks in a relaxed atmosphere, with discussions around a cup of morning coffee, a lunch break, or an afternoon tea depending on the time zone of the participants.
The time slots of each presentation will be accommodated to be the most comfortable for the presenter and listeners from their targeted research area.

The talks will be held online via Zoom. Click here to join the Zoom meeting (Meeting-ID: 988 6914 5922; code: YRA-S2024).

Next presentation: December 10th, at 3:00 pm (UTC)

Seminar Zoom link

Click here to join the Zoom meeting.
Meeting-ID: 988 6914 5922
Code: YRA-S2024

You can convert to your local time zone with, e.g., timeanddate.com.

Chrysocolla at high temperatures: understanding Pre-Hispanic metallurgy through Collahuasi slag analysis (Tarapaca, Chile)
Sibylle Manya (National Centre for Research and Restoration in French Museums, France)

Co-authors: B. Mille, V. Figueroa Larre, T. Bataille, L. Le Pollès, J.-B. d’Espinose de Lacaillerie

Keywords: Chrysocolla characterization; Thermal analysis; Pre-Hispanic copper metallurgy

Abstract:
Ujina-Collahuasi is an archaeological site located in the Atacama Desert in Chile, renowned as a major center for copper production during the pre-Inca and Inca periods. Pre-Hispanic metallurgists utilized bench-shaped granodiorite furnaces to smelt ore, leveraging the wind to achieve high temperatures and extract copper in the form of metallic beads. The resulting slag, rich in silicon, exhibits various mineralogical phases, notably yellow-green or yellow-orange phases that are of particular interest. These phases, rich in copper and silicon, may be attributed to the prevalence of chrysocolla among the ores used. This study focuses on a characterization of chrysocolla, a copper silicate with an amorphous and controversial structure. At ambient temperature, several analytical techniques (PIXE, SEM-EDS, and solid-state NMR) were employed to overcome challenges related to its variable chemical composition and disordered crystalline structure. At high temperatures, the thermal decomposition of chrysocolla was investigated by heating several samples to different temperatures and characterizing them using various techniques (optical microscopy, XRD, IR spectroscopy, SEM-EDS). Additionally, an in-situ study was conducted, providing XRD scans of a sample subjected to increasing temperatures. The results obtained enhance our understanding of the transformation of chrysocolla observed in the pre-Hispanic slag from Collahuasi and the evolution of metallurgical techniques. Previous studies have been supplemented by analyzing slags from excavations in the Ujina 10 sector, including three furnaces dated to different periods. The objective was to identify any changes in copper reduction techniques between the pre-Inca and the Inca occupation.


Optical microscopy image in dark field of an archaeological slag

Programme

Time: 8:30 am (UTC)
Title: Copper technologies in Taiwan and the Philippines during the Metal Age
Keywords: Copper-based metallurgy; South-East Asia; Metal Age; Maritime exchange
Abstract: In the island contexts of South-East Asia and Taiwan, the development of metallurgy followed a different time-period and pattern compared to the Mainland. Indeed, in Taiwan and the Philippines, there is no mention of a Bronze and Iron Age but of a Metal Age (or directly an Iron Age) since iron, copper-based, glass and precious metal technologies seem to appear together in archaeological context. The first signs of metallurgy in the island contexts of Taiwan and the Philippines appear to have followed similar patterns; no Bronze Age, no sign of primary production, only secondary production and where maritime exchange is a central issue in the development of these technologies. Metallurgy would probably have reached the islands through maritime contacts with mainland Southeast Asia, where metallurgical practices took place earlier (11-13th BC) and maritime contacts have been known since the Neolithic period, notably through nephrite objects. Current evidence seems to support that Taiwan and the Philippines did not have any primary production of copper during the Metal Age but still needs to be proved by future studies. It has been proposed that raw materials and some finish objects were imported. However, secondary production activities are attested with molds, both in Taiwan and the Philippines.

Copper and its alloys are one of the materials thought to come from the maritime interactions and thus represent an important proxy to study the movements of goods/communities/technologies between the different areas around the South China Sea. Regarding the similarities observed between Taiwan and the Philippines as well as the ancient exchanges attested between the two areas, the current project aims to collect data in order to start discussing the copper-based traditions and the potential exchange networks. We also hope that the data can contribute to understand the origin, timing and development of copper-based metallurgy in Taiwan and the Philippines and its link to other regions for the acquisition of raw materials/finish objects. Around 50 scientific samples, mainly in Taiwan so far, have been collected to be studied following an archaeometric approach (Optical Microscopy, SEM-EDS and ongoing lead isotope analyses). In Taiwan, the current results show that artefacts are diverse, both in terms of their forms (such as bells, vessels, knife handles, Chinese coins, unidentified fragments) and composition (alloys), including bronze, leaded-bronze, high-tin bronze, unalloyed copper, leaded copper and brass. Some artefacts result probably from oversea exports. In Taiwan, differences can also be observed between sites, probably as a result of the different metallurgical practices identified during the excavations, such as secondary production activities.

Time: 8:00 am (UTC)
Title: Tinos’ lost ancient serpentinite quarry (Cyclades, Greece): an interdisciplinary approach
Keywords: Stone analysis; Serpentinite; Cyclades Greece; Ancient quarry
Abstract: The study of marble and coloured-stone production centres of antiquity carries a significant role in the scientific community, being a subject where natural and archaeological sciences may interweave, aiming to decipher quarrying methods, trade and the unique geological fingerprint of the stones. Contemporary quarrying activity on Tinos Island, Greece, is focused on ophicalcites (metasomatic rock consisting of serpentine and carbonates), however, the studied ancient quarry of Ag. Georgios Ras (Ras serpentinite) consist of a distinctive serpentinite, with no carbonate participation when compared to the neighbouring ophicalcite. Ras serpentinite was quarried from two small-scale open pits demonstrating tool marks, grooves, as well as holes for inserting wedges. The serpentinite consists of, macroscopically and mineralogically, two serpentine varieties, a dark green demonstrating massive texture and a light green forming a network of fibrous serpentine. Research efforts on serpentinite provenance are limited and lack information and data when compared to the study of white marble. This study aims to enrich the present database using a variety of techniques, including XRD, LA-ICP-MS and physicomechanical tests to determine the geochemistry, geotectonic environment of formation and strength characteristics of the Ras serpentinite. The geological study is framed, in an interdisciplinary approach, by archaeological and lichenometrical data and observation to further shed light upon the newly explored Ras serpentinite quarry.

Time: 8:00 am (UTC)
Title: Plant and insect remains as indicators for waterlogged dung layers – The example of the Neolithic lakeshore settlement Mooswinkel in the Austrian Alps
Keywords: Stable manure; Pile dwelling; Archaeobotany; Archaeoentomology; Late Neolithic
Abstract: Stable manure preserves well in waterlogged archaeological sediments. The organic refuse provides a wealth of information about the site’s economy, forest resources, and impact on the environment. However, the recognition of middens and manure in sediment layers is not always straightforward. In the case study of the Late Neolithic pile dwelling Mooswinkel at the lake Mondsee in Austria, dung, botanical macro- and microremains, as well as invertebrates identified the sediment as stable manure from goat, sheep and cattle farming. Furthermore, the season of the layer formation could be recognized. Materials investigated included pollen, bryophytes, plant fruits and seeds, leaves, branches and bud scales of woody plants, as well as insect remains. In addition, plant microremains in dung were analysed. The results of this multi-material study show that leaf hay and grass hay were used as fodder during the winter season. The impact of fodder acquisition and pasturing on the forest could be reconstructed, showing the formation of a mosaic landscape of natural and semi-natural habitats.

Time: 2:00 pm (UTC)
Title: Biomolecular insights into Magdalenian ungulates from Petersfels (Hegau Jura, southwestern Germany) via ZooMS and stable isotope analysis
Keywords: Magdalenian; ZooMS; Stable isotopes; Zooarchaeology; Paleoenvironment; Ungulates
Abstract: After the Last Glacial Maximum, ameliorating climates facilitated the recolonization of Central Europe by human and animal groups. Petersfels, situated in the Hegau Jura of southwestern Germany, evidences the later stages of this repopulation, dating to ~16-14 ka cal BP. Over the past hundred years, numerous excavations at the site have revealed an exceptional record of Magdalenian subsistence including abundant lithic and osseous material, personal ornaments, engravings, and female figurines. Faunal remains are particularly relevant, as they archive information on human and animal lifeways as well as the broader post-LGM environmental context. However, despite this great potential, little is known about the paleoecological context of the site or the broader Hegau Jura. Here, we present new biomolecular analyses of the Petersfels faunal assemblage, which help to illuminate the paleoecology of the region. Zooarchaeology by Mass Spectrometry (ZooMS) was applied to identify rare taxa and to differentiate between closely related species. We also conducted stable isotope analyses of carbon (δ13C) and oxygen (δ18O) from serially sampled equid and bovid tooth enamel carbonate. The latter contributes to our understanding of local paleoecology during the Magdalenian and the status of human and animal communities during post-LGM climatic change. More broadly, this work shows how heritage collections like Petersfels are still immensely valuable, especially with the application of modern biomolecular techniques.

Time: 12:00 pm (UTC)
Title: The technology of polychrome glazed ceramics in Ifriqiya: new data from the Medjerda Valley
Co-authors: H. Möller, C. Fenwick, P. Quinn, I.C. Freestone, M. Chaouali, P. von Rummel
Keywords: Ifriqiya; Medieval glazed ceramics; Pottery technology; Petrography; Compositional analyses
Abstract: Ifriqiya (roughly Tunisia and eastern Algeria) is believed to have played a significant role in the diffusion of ceramic glazed technologies into other regions of the Western Mediterranean. However, due to limited analysis on North African glazed ceramics, its role in technology transfer remains poorly understood. This paper uses petrographic, SEM-EDS and LA-ICP-MS analyses to understand the technology employed in the production of Tunisian ceramics through the study of polychrome glazed ceramics from medieval settlements at the sites of Chimtou (ancient Simitthus) and Bulla Regia, Tunisia, dated to the late ninth-twelfth century. The results provide new insights on workshops practices, on the origin of the ceramics and on regional inland exchange networks.

Time: 3:00 pm (UTC)
Title: Chrysocolla at high temperatures: understanding Pre-Hispanic metallurgy through Collahuasi slag analysis (Tarapaca, Chile)
Co-authors: B. Mille, V. Figueroa Larre, T. Bataille, L. Le Pollès, J.-B. d’Espinose de Lacaillerie
Keywords: Chrysocolla characterization; Thermal analysis; Pre-Hispanic copper metallurgy
Abstract: Ujina-Collahuasi is an archaeological site located in the Atacama Desert in Chile, renowned as a major center for copper production during the pre-Inca and Inca periods. Pre-Hispanic metallurgists utilized bench-shaped granodiorite furnaces to smelt ore, leveraging the wind to achieve high temperatures and extract copper in the form of metallic beads. The resulting slag, rich in silicon, exhibits various mineralogical phases, notably yellow-green or yellow-orange phases that are of particular interest. These phases, rich in copper and silicon, may be attributed to the prevalence of chrysocolla among the ores used.
This study focuses on a characterization of chrysocolla, a copper silicate with an amorphous and controversial structure. At ambient temperature, several analytical techniques (PIXE, SEM-EDS, and solid-state NMR) were employed to overcome challenges related to its variable chemical composition and disordered crystalline structure. At high temperatures, the thermal decomposition of chrysocolla was investigated by heating several samples to different temperatures and characterizing them using various techniques (optical microscopy, XRD, IR spectroscopy, SEM-EDS). Additionally, an in-situ study was conducted, providing XRD scans of a sample subjected to increasing temperatures.
The results obtained enhance our understanding of the transformation of chrysocolla observed in the pre-Hispanic slag from Collahuasi and the evolution of metallurgical techniques. Previous studies have been supplemented by analyzing slags from excavations in the Ujina 10 sector, including three furnaces dated to different periods. The objective was to identify any changes in copper reduction techniques between the pre-Inca and the Inca occupation.