Hostname: page-component-797576ffbb-vjhkx Total loading time: 0 Render date: 2023-12-04T13:30:10.715Z Has data issue: false Feature Flags: { "corePageComponentGetUserInfoFromSharedSession": true, "coreDisableEcommerce": false, "useRatesEcommerce": true } hasContentIssue false

Conditions Involved in Dating Terrestrial Shells

Published online by Cambridge University Press:  18 July 2016

Jacques Evin
Centre de Datations et d'Analyses Isotopiques, Université, Claude-Bernard, Lyon, France
Joëlle Marechal
Centre de Datations et d'Analyses Isotopiques, Université, Claude-Bernard, Lyon, France
Christiane Pachiaudi
Centre de Datations et d'Analyses Isotopiques, Université, Claude-Bernard, Lyon, France
J J Puissegur
Département de Géologie, Université de Dijon, France
Rights & Permissions [Opens in a new window]


Core share and HTML view are not possible as this article does not have html content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Mollusks living only on ground surface can be expected to give the most reliable results in 14C dating from carbonates of continental origin. One may assume they have a homogeneous biotope and are not affected by any hard-water effect. In order to verify these assumptions and to test shells as routine dating material, results from terrestrial gastropods are compared with other 14C dates from classic biologic material, such as peat, charcoal, or bone, collected in the same archaeologic or geologic levels in miscellaneous places. Two sites were selected for which other chronologic data, such as prehistoric industries or malacologic diagrams were available.

All results indicate older values for 14C shell dates. The discrepancy between “normal” and snail dates amounts to 300 to 1200 14C years and remains the same whatever the absolute age of the sample. All 13C values of perfectly cleaned shells are between —5 to —10%, versus PDB. The initial 14C content of shells that is too low may be different according to species, as suggested by 13C variations.

Although fairly constant, this deviation of 14C ages generally makes such samples unreliable for most archaeologic studies, which often need more precise results. However, some measurements were performed on microfauna shells from several Würmian loess to show that dating of shells may be useful in fairly ancient geologic sediments for lack of better carbonaceous samples. Good agreement of some snail dates with expected sediment ages point to the importance of proper sample selection and pretreatment that might be checked by 13C measurements.

Dating Various Materials
Copyright © The American Journal of Science 


Broecker, W S and Walton, A, 1959, The geochemistry of 14C in fresh-water systems: Geochim et Cosmochim Acta, v 16, p 1538.Google Scholar
Camps, G, Delibrias, G, and Thommeret, J, 1973, Chronologie des civilisations préhistoriques du Nord de l'Afrique d'après le radiocarbone: Libyca, v 21, p 6589.Google Scholar
Keith, M L and Anderson, G M, 1963, Radiocarbon dating: fictitious results with mollusk shells: Science, v 141, p 634637.Google Scholar
Labeyrie, J, Duplessy, J C, Delibrias, G, and Letolle, R, 1967, Etude des températures des climats anciens par la mesure de l'oxygène-18, du carbone-13 et du carbone-14 dans les concretions des cavernes: Radio dating meth, low level count conf, Proc, IAEA, Monaco 1967, p 153160.Google Scholar
Laplace, G, 1953, Les couches à escargots des cavernes pyrénéennes et le problème de l'Arisien de Piette: Soc préhist France Bull, no. 4, p 199211.Google Scholar
Puissegur, J J, 1976, Mollusques continentaux quaternaires de Bourgogne: Thesis Univ Dijon, 241 p.Google Scholar
Rubin, Meyer, Likins, R C, and Berry, E G, 1963, On the validity of radiocarbon dates from snail shells: Jour Geology, v 71, no. 1, p 8489.Google Scholar
Séronie-Vivien, M, 1973, Premiers résultats obtenus dans l'Azilien et le Magdalenien de la grotte de Pégourié, à Caniac, Lot: Soc spéleol préhist Bordeaux, Bull, v 22-23, p 3761.Google Scholar
Srdoc, Dusan, Sliepcevic, Adela, Obelic, B, and Horvatincic, N, 1977 Rudjer Boskovic Inst radiocarbon measurements IV: Radiocarbon, v 19, p 465475.Google Scholar
Tamers, M A, 1970, Validity of radiocarbon dates on terrestrial snail shells: Am Antiquity, v 35, no. 1, p 94100.Google Scholar
Thévenin, A and Marnot-Houdayer, J, 1978, l'Etat actuel des coupes replacées dans le cadre des croquis de E Schumacher et de P Wernert: Recherche géog Strasbourg, v 7, p 1726.Google Scholar
Vita-Finzi, C, 1974, Age of valley deposits in Périgord: Nature, v 250, p 568570.Google Scholar
Wernert, P, 1957, Stratigraphie paléontologie et préhistoire des sédiments quaternaires d'Alsace. Achenheim: Mem Serv Carte Geol Alsace-Lorraine, v 14, 259 p.Google Scholar