Skip to navigation – Site map

Beads excavated from Antsiraka Boira necropolis (Mayotte Island, 12th-13th centuries)

Colouring agents and glass matrix composition comparison with contemporary Southern Africa sites
Agents colorants et matrices vitreuses des perles de la nécropole d’Antsiraka Boira (Île de Mayotte, XIIe-XIIIe siècles). Comparaison avec les sites contemporains d’Afrique Australe
Noémi Fischbach, Anh-Tu Ngo, Philippe Colomban and Martial Pauly
p. 83-102

Abstracts

About hundred out of three hundred colored beads excavated from the necropolis of Antsiraka Boira (AB), in Mayotte Island (12-13th c.) were classified according to Wood’s morphological criteria and studied with a portable Raman spectrometer (532nm). Based on the recorded spectra, 22 beads were identified as representative and further analyzed in the laboratory with High-Resolution Raman spectrometers, using wavelengths of 458, 633 and 785nm. Additional SEM-EDS analysis was carried out on the surface and, sometimes, the bead cross-section. It turns out that white beads are made of aragonite and that almost all other beads have a soda glass matrix. Pyrochlore (yellow), amber/“Fe-S” (black), manganese oxide (black), copper metal nanoparticles (red), and Cu2+ ions (turquoise) chromophores were identified. Some red, yellow, black and turquoise beads also show the signature of chromium-doped tin sphene that could therefore be used as a marker. Most beads from the AB site can be classified as “Indo-Pacific”, revealing a similarity with the contemporary South African site of K2 (close to Mapungubwe). However, some red and black beads are similar to molten ceramic beads from the Vohemar Islamic necropolis (13-17th century AD, Madagascar Island). The on-site Raman analysis appears sufficient for the identification of chromophores and glass types.

Top of page

Excerpt

Cairn

Full-text article available to subscribers or on a "pay per view" basis. It will be available on this URL in January 2020.
Read it

Outline

1. Introduction
2. Materials and methods
Beads
Analyses
Scanning electron microscopy (SEM-EDS)
3. Results
Identification of the chromophores
Yellow beads
Red beads
Turquoise Beads
Black Beads
White beads
Other Phases
Glassy matrix
4. Discussion
Yellow beads
Red beads
Blue and turquoise beads
Black Beads
White beads
Glass matrices
Origin / production time
A comparison with the beads of Mapungubwe and K2 sites
5. Conclusion

First lines

1. Introduction

At the beginning of the first millenium AD, the Indian Ocean became a region of long-distance trade between the Middle East, China, India, South Asia and Africa. Over the centuries, mostly thanks to monsoons, it was organized into a space around which the first World Trade system was built (Beaujard, 2009; Beaujard, 2012). Indeed, by its geographical situation, the Indian Ocean is subject to the phenomenon of monsoon winds whose seasonal fluctuation determined navigation and commerce in the area (Nativel & Rajaonah, 2007). At the time, it was possible to travel from Asia-to-Africa and up to the entrance of the Mozambique Channel in a single season; on the other side, trade to ports located more to the South needed a waiting period for the next cycle. Livestock, raw or processed materials like ivory, pearls, wood, metals, pottery and glass beads have travelled over the ...

Top of page

References

Bibliographical reference

Noémi Fischbach, Anh-Tu Ngo, Philippe Colomban and Martial Pauly, « Beads excavated from Antsiraka Boira necropolis (Mayotte Island, 12th-13th centuries) », ArcheoSciences, 40 | 2016, 83-102.

Electronic reference

Noémi Fischbach, Anh-Tu Ngo, Philippe Colomban and Martial Pauly, « Beads excavated from Antsiraka Boira necropolis (Mayotte Island, 12th-13th centuries) », ArcheoSciences [Online], 40 | 2016, Online since 30 December 2018, connection on 27 June 2017. URL : http://archeosciences.revues.org/4774 ; DOI : 10.4000/archeosciences.4774

Top of page

About the authors

Noémi Fischbach

Sorbonne Universités, UPMC Université Paris 6 – CNRS, IP2CT, UMR 8233, MONARIS, 75005, Paris, France. noemi.fischbach@gmail.com

Anh-Tu Ngo

Sorbonne Universités, UPMC Univ Paris 06 – CNRS, IP2CT, UMR 8233, MONARIS, 75005, Paris, France. anh-tu.ngo@courriel.upmc.fr

Philippe Colomban

Sorbonne Universités, UPMC Univ Paris 06 – CNRS, IP2CT, UMR 8233, MONARIS, 75005, Paris, France. CNRS, IP2CT, UMR 8233, MONARIS, 75005, Paris, France (philippe.colomban@upmc.fr)

By this author

Martial Pauly

INALCO-CROIMA, 75007, Paris, France celmartial@hotmail.com

Top of page

Copyright

Tous droits réservés

Top of page