The Rongorongo Tablets from Easter Island: Botanical Identification and 14C Dating
Orliac, Catherine, Archaeology in Oceania
Seven Easter Island rongorongo tablets and one pectoral, now housed in various museums, are described. All are made of Thespesia populnea, a wood used widely in Polynesian traditional ceremonies. Wood from one tablet is dated to 80 +/- 40 BP.
Keywords: Easter Island, Rapa Nui, rongorongo, Thespesia populnea, 14C dating.
Today's palaeographic linguists agree to qualify as writing the signs discovered on twenty-one tablets (rongorongo), two crescent-shaped pectorals (rei miro), one staff, and one birdman representation from Easter Island. The presence of writing on such a tiny, extremely isolated island is an enigma. The issue of dating its appearance triggers many controversies. Since no convincing answers have yet been presented, it appears fundamental to develop a new approach focusing directly on the raw material. Consequently, the botanical identification of seven rongorongo tablets and the 14C dating for one of them should allow a better understanding of their age and nature and therefore help to appreciate the tablets' symbolic value in the context of Polynesian cosmogony.
Method of investigation
The subjects of our study are some tablets which are among the most beautiful and the best preserved of the twenty-one known. We focused on the two tablets in Santiago de Chile (catalogue numbers 314 and 315), the Arnku Kurenga and Mamari tablets (no catalogue numbers) of the Congregation of Sacred Hearts of Jesus and Mary (SSCC) in Rome, the small St Petersburg tablet (catalogue number 402/13-1), the London tablet (catalogue number 1903-150) and the London rei miro (catalogue number 9295). We shall also take into account the botanical determination realized in 1934 on the large tablet of the Museum of Ethnography in Vienna (catalogue number 22869).
Macroscopic examinations with a stereo microscope were carried out by the author on the surface of the rei miro and on all these rongorongo except large Vienna tablet. Samples a few millimetres in length and in width and a few tenths of a millimetre thick were also removed by the author with a razor blade from St Petersburg tablet, Aruku Kurenga and Mamari tablets. These samples were orientated perpendicularly to the axis of the tree (transverse section), perpendicularly to the wood's rays (tangential section) and parallel to the rays (radial section); they were examined under episcopic microscope (100 X to 400 X) and scanning electron microscope (1000 X to 4000 X). The botanical identification was realized by the author in the ethnobiology laboratory of Museum national d'Histoire naturelle in Paris. This identification was done by comparison with a reference collection housed in the xylariorum of this museum.
Presentation of the rongorongo and the pectoral studied
In 1996, during an exhibition organised by the Musee d'Aquitaine in Bordeaux, the large and small Santiago tablets were displayed in France for the first time. These two prestigious objects had been given by Father Roussel, in 1870, to the officers of the Chilean corvette O'Higgins (Fisher 1997: 442-50). The small Santiago tablet, which measures 32 cm in length by 12.1 cm wide and 1.8 cm thick, has 720 glyphs. The large tablet measures 44.5 cm in length, 11.6 cm wide and 2.7 cm thick; it is covered with more than 1500 glyphs. One of its sides has a deep burned groove indicating that the object was later used in a device for making fire through friction. No samples were taken from these objects which are entirely covered in rongorongo motifs. However, these two tablets are carved in the direction of the wood fibres, and a macroscopic analysis of the surface, enlarged 16 to 80 times, made it possible to observe the wood's structure in tangential section.
The Mamari and Aruku Kurenga tablets in the SSCC collection at Rome were studied in 2002. The Aruku Kurenga tablet measures 41 cm in length, 15.2 cm wide and 2.3 cm thick; it is covered on both sides by 1290 glyphs and comes from the collection of Monseigneur Jaussen, collected by Fathers Roussel and Zumbohm on Easter Island in 1870 (Fisher 1997: 427). …