Neandertal Lithic Industries at La Quina

4. The Chronological and Paleoenvironmental Setting of the Prehistoric Sequence at the Station Amont

The Nature and Importance of the Chronological and Paleoenvironmental Evidence An understanding of the natural habitat and the chronological position of the succession of events that contributed to the archaeological and paleontological record at the station amont is essential for a culturally meaningful interpretation of the accumulation of artifacts and animal bone at the site. At the time that this report is in preparation , much of the material and data gathered during the recent excavation are still in the process of analysis, and the interpretation presented here is based upon those reports completed to date, in combination with pertinent evidence reported by the Henri-Martins. The results in hand from the recent work include an analysis of sequences of palynological samples from the upper and lower deposits, partial and preliminary reports on the paleontological collections, and chronometric determinations of age for samples from the upper levels. The sedimentological sequence has been partially analyzed but not reported, and collections of microvertebrates from the upper levels remain unanalyzed. The interpretation of this evidence begins with the geological deposits, followed by the paleontological and palynological sequences, and then the chronometric data. A summary reconstruction based upon all of the evidence at hand concludes this chapter and provides a perspective on the natural conditions under which the lithic materials accumulated. The Sedimentological Record and the Interpretation of the Depositional History A detailed study of the sediments sampled in the excavation was initially undertaken by Thomas D. Young of the University of Arizona but was interrupted by health issues and has not been resumed. Young’s unpublished data include largely complete compilations of granulometry of limestone and other sedimentary components, including bone and flint. Small portions of these data have been incorporated into the present study as they relate to particular problems of interpretation of the cultural sequence . In a report prepared in 1994, following the last excavation season, Young presented a preliminary interpretation of the sequence from Beds 6d through 2 and for portions of Beds N and M1. This information is incorporated in the following interpretation of the depositional history that is otherwise based primarily on the visual inspection of the exposed sediments by André Debénath and myself. To some extent, these interpretations of the events and conditions that are represented in the strata exposed in the new profile parallel those in the general sequences postulated by Dr. Henri-Martin and Mlle. Henri-Martin. The major depositional units in the natural and cultural accumulation of sediments and artifacts can be summarized as follows. (1) An initial sequence of predominantly quartz sands, intercalated with thin clay lenses (Beds O and P),1 was deposited by a slow-flowing stream (the Voultron) on the bedrock shelf in front of the massive éboulis deposit that had accumulated earlier against the base of the cliff. Limestone éboulis clasts of varying size, weathered from the cliffs above, are present throughout these sands. These levels have yielded our earliest cultural evidence, but the aqueous habitat represented by this phase, not surprisingly , appears to have been little utilized by hominids. Only a few widely scattered artifacts and very few paleontological specimens were recovered here, although soft fragments of disintegrated bone were relatively common. The most spectacular paleontological find was an isolated massive fragment of a bison skull lying directly on the bedrock surface. Despite the occasional occurrence of scattered fragments of shell, our attempts to recover identifiable mollusks were unsuccessful. The presence of cal4 The Chronological and Paleoenvironmental Setting of the Prehistoric Sequence at the Station Amont 74 Neandertal Lithic Industries at La Quina cified roots in the sands at the base of Bed P, about 10 cm above the bedrock (Figure 4.1), is most probably the result of tree or shrub growth at some time subsequent to the accumulation of the sands. We did not recover any artifacts similar to those described by the Henri-Martins as prémoustérien at the base of the sands. (2) The layer of greenish gray sandy clay (Bed N) that overlies the sands appears, from its lack of oxidation, to also be of subaqueous origin and seems to represent a shallow pond in front of the massive éboulis slope. Limestone éboulis clasts of varying sizes are ubiquitous throughout this layer. Young’s preliminary sedimentological analysis suggested a period of relatively mild temperatures and high humidity with evidence of local flooding. The circumstances that slowed the waters of the Voultron to form a pond at this time are, of course, unknown...