Limpet Shells from the Aterian Level 8 of El Harhoura 2 Cave (Témara, Morocco): Preservation State of Crossed-Foliated Layers

Abstract : The exploitation of mollusks by the first anatomically modern humans is a central question for archaeologists. This paper focuses on level 8 (dated around * 100 ka BP) of El Har-houra 2 Cave, located along the coastline in the Rabat-Témara region (Morocco). The large quantity of Patella sp. shells found in this level highlights questions regarding their origin and preservation. This study presents an estimation of the preservation status of these shells. We focus here on the diagenetic evolution of both the microstructural patterns and organic components of crossed-foliated shell layers, in order to assess the viability of further investigations based on shell layer minor elements, isotopic or biochemical compositions. The results show that the shells seem to be well conserved, with microstructural patterns preserved down to sub-micrometric scales, and that some organic components are still present in situ. But faint taphonomic degradations affecting both mineral and organic components are nonetheless evidenced, such as the disappearance of organic envelopes surrounding crossed-foliated lamellae, combined with a partial recrystallization of the lamellae. Our results provide a solid case-study of the early stages of the diagenetic evolution of crossed-foliated shell layers. Moreover, they highlight the fact that extreme caution must be taken before using fossil shells for palaeoenvironmental or geochronological reconstructions. Without thorough investigation, the alteration patterns illustrated here would easily have gone unnoticed. However, these degradations are liable to bias any proxy based on the elemental, isotopic or biochemical composition of the shells. This study also provides significant data concerning human subsistence behavior: the presence of notches and the good preservation state of limpet shells (no dissolution/recrystallization, no bioerosion and no abrasion/fragmentation aspects) would attest that limpets were gathered alive with tools by Middle Palaeolithic (Aterian) populations in North Africa for consumption.
Document type :
Journal articles
Complete list of metadatas

Cited literature [103 references]  Display  Hide  Download

https://hal-cea.archives-ouvertes.fr/cea-01253552
Contributor : Serge Palacin <>
Submitted on : Monday, January 11, 2016 - 8:29:43 AM
Last modification on : Thursday, July 11, 2019 - 2:10:07 PM
Long-term archiving on : Tuesday, April 12, 2016 - 11:04:31 AM

File

PlosOne.0137162.pdf
Files produced by the author(s)

Identifiers

Citation

Julius Nouet, Corinne Chevallard, Bastien Farre, Gernot Nehrke, Emilie Campmas, et al.. Limpet Shells from the Aterian Level 8 of El Harhoura 2 Cave (Témara, Morocco): Preservation State of Crossed-Foliated Layers. PLoS ONE, Public Library of Science, 2015, pp.0137162. ⟨http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0137162⟩. ⟨10.1371/journal.pone.0137162⟩. ⟨cea-01253552⟩

Share

Metrics

Record views

439

Files downloads

262