The Ebro Frontier: a Model for the Late Extinction of Iberian Neanderfhals, in STRINGER, C.; BARTON, R.N.E.; FINLAYSON, C
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ZI LH~O,J. - The Ebro frontier: a model for the late extinction of Iberian Neanderfhals, in STRINGER, C.; BARTON, R.N.E.; FINLAYSON, C. (eds.) - {{Neanderthals on the edge: 150th anniversary conference of the Forbes' Quarry discovery, Gibraltar)), Oxford, Oxbow Books, 2000, p. 11 1-1 21. The Ebro Frontier: A Model for the Late Extinction of Iberian Neanderthals Introduction discuss the archaeological data substantiating the model, The idea that Mousterian industries and, consequently, focusing on the Portuguese material, and elaborate on its Neanderthals, survived in Valencia and Andalucia until c. implications for the study of Neanderthal extinction. 28-30 ka, i.e., significantly later than elsewhere in Western Europe, was first put forward on a sound geoarchaeological The late Mousterian and the Aurignacian of basis by Vega (1990) and Villaverde and Fumanai (1990). Confirmation of the concept would soon come from reliable Portugal radiometric dates for several Portuguese cave and open Table 12.1 shows an annotated list of all radiometric air sites (Zilhiio 1993;Raposo 1995) and for the Andalucian dates currently available for the Portuguese Middle cave site of Zafarraya (Hublin et al. 1995). Meanwhile, Palaeolithic. Several sites have results later than 40 ka however, much earlier results had also been obtained for that cannot be accepted. In most cases, rejection is a Aurignacian contexts in Cantabria and northern Catalonya consequence of technical problems in the dating pro- (Bischoff et al. 1989, 1994; Cabrera and Bischoff 1989; cedures. Low collagen or low uranium content, for Maroto 1994; Cabrera et al. 1996), suggesting that the instance, immediately force us to remove from further establishment of Upper Palaeolithic modern humans in consideration all the post-28 ka dates, which are in any those regions dated to c. 38-40 ka. case incompatible with the cultural stratigraphy of the These facts inspired the formulation of the Ebro frontier Last Glacial (Zilhiio 1995, 1997). model (Figure 12.1), first presented in October 1991, in The inadequate nature of the dated material also brings the Madrid Conference on the origins of anatomically into question acceptance of the radiocarbon results for modern humans (Zilhiio 1993). From the spatial and Columbeira (Delibrias et al. 1986). The need to reject temporal aspects of the Iberian situation the proposition these results is also suggested by the stratigraphic context. was derived that, in Western Europe, the replacement of ~ccordin~to Raposo and Cardoso (1998a), the sequence Neanderthals by moderns had not been the outcome of a begins with a 0.5 m package rich in archaeological gradual geographic progression of the latter but a punctu- remains: levels 7-9. These are overlain by 1.5 m of ated process during which stable biocultural frontiers might deposits which, although poor in artefacts, are still entirely have lasted for significant amounts of time. One such Middle Palaeolithic: levels 4-6. Accepting the radio- frontier, largely corresponding to a major biogeographical carbon age of c. 26 ka for level 7 necessarily entails, divide (cf. Gamble 1986), would have been located along therefore, accepting that the Mousterian industries in the Cantabro-Pyrenean mountains: for possibly as long as levels 4-6 would have been contemporary with the later 10,000 years but certainly for at least some 5,000 years, Upper Palaeolithic of the rest of Europe. Zbyszewski et the Ebro basin would have separated the Mousterian al. (1977) argued along those lines on the basis of their Neanderthals of Iberia from the Aurignacian Moderns of analysis of foliates recovered at the site of Arneiro. Their Cantabria, Aquitaine and northern Catalonya (Zilhiio 1993, hypothesis of a direct transition from the Mousterian to 1995, 1997, 1998, in press). the Solutrean in Portugal is, however, empirically This hypothesis has since received considerable support untenable. Not only are Aurignacian and Gravettian sites from many different lines of evidence. This paper will well described and dated in the region but the Arneiro m A Aurignacian l (with split-based bone points) Long MP-UP sequence lacking an Aurignacian l Benelto* Late Mousteriansequence with Neanderthalremains The Ebro Frontier (2 35 to I 30 kyr BP) Gorham's Figure 12.1: The Ebro frontier. For at least 5 ka a stable biocultural frontier separated Aurignacian modern humans living in Contabria and norrhern Corolonyofrom the Mousrerian Neonderrhols thot continued ro ~hrivein rhe rest of Iberia unril c. 20-30 ka. foliates are neither Mousterian nor Solutrean points but two other bones attributed to Homo by Antunes - a phalanx Neolithic-Chalcolithic preforms for bifacial knives and and a metacarpal - clearly belong to a carnivore). halberds (Zilhiio 1995, 1997). Brugal and Raposo (pers. comm) consider that the Foz Figure 12.2 gives the location of those sites for which do Enxarrique bone assemblage represents for the most the recent dates obtained are technically acceptable and part a natural accumulation along the river margin. The compatible with regional chrono-stratigraphic patterns. human occupation coincided topographically but not From north to south, these are the open air site of Foz do behaviourally with the bone scatter (except, perhaps, in Enxarrique (Rodso), and the cave sites of Furos and the case of red deer) and, therefore, the dated horse teeth Caldeirlo (Tomar), Almonda (Tomes Novas), Pedreira are not an anthropic component of the sediments. The de Salemas (Loures) and Figueira Brava (Setlibal). Furos depositional environment. suggesting a rapid rate of and Pedreira de Salemas, however, yielded very small accumulation, however, warrants their geochronological assemblages, and some of the other sites are not without association with the artefacts. The numerous lithic problems either. assemblage remains largely undescribed but is unam- At Figueira Brava, the chaotic nature of the excavated biguously Middle Palaeolithic. Raposo and Cardoso deposit suggests that it may in fact correspond to a (1998b) consider that another open air site, Concei~Po redeposition of material eroded from an inner chamber. (Alcochete), is broadly contemporary with Foz do Given that only Middle Palaeolithic artefacts are present Enxarrique, on the basis of a c. 27.2 ka OSL date on (Cardoso and Raposo 1995), it is clear that the dated wind-blown sediments covering the archaeological level. Patella shells must have been accumulated by Middle Since the latter is separated from the former by a major Palaeolithic humans. Consequently, the inference thar geological unconformity, all that can be safely said about Mousterian technologies survived in the region until c. 31 the age of the occupation, Ilowever, is that it must be ka is legitimate. To what extent the lithic and mammal dated between c. 27 and, g~venthe OSL result for the assemblages recovered in level 2 are entirely contemporary underlying deposits, c. 75 ka (Table 12.1). with the dated shells, or represent instead the mixed The late survival of Mousterian industries in Portugal product of many different occupations taking place documented by Figueira Brava and Foz do Enxarrique is throughout a much longer time span, remains, however, clearly confirmed by the radiometric and chronostrati- to be seen. It is not certain, therefore, whether the upper graphic data available for the two key cave sites of left second premolar considered to show Neanderthal Caldeirlo and Oliveira (Almonda karstic system). Under affinities by Antunes (1990-9 l) is indeed as recent as the a 2.5 m deep Holocene and Tardiglacial sequence, occupation episode documented by the Parella shells (the CaldeirHo contains 4 m of ~ouiterianthrough to Solutrean THE EBRO FRONTIER: A MODEL FOR THE LATE EXTINCTION OF IBERIAN NEANDERTHALS 113 Table 12.1: Radiometric results for the Middle Palaeolithic of Portugal. (sources: Antunes 1990-91; Antunes et al. 1989; Zilhdo 1995, 1997; Zilhdo and Mckinney 1995; Raposo 1995; Mckinney 1996; Raposo and Cardoso 1998). Site Level Sample Method Lab Reference Age BP Comment Equus (tooth EVS Cone U-Th SMU-23lE1 35,000+2.000 Low 230Thl232Th rat10 Almonda. EVS enamel) Almonda, Gruta da 8 Burnt bone GrA-10200 3 1,900+200 Alkallne fraction dated Ol~velm C14 9 Burnt bone GrA-9760 38.390i480 Alkaline fractlon dated C14 9 Burntbone Beta- 1 1 1967 40,420i 1,220 Moustenan Equus (tooth 53'000+5'600-5' U-7% SMU-3080247~2 Average of the two detemnat~ons,c 62.000 Cone enamel) 300 SMU-247EI 70.250i9.000 Low collagen content (0.32%N, 3.66%C, Gmta do Calde~do K top (J6) Cervus OxA-5541 18,060t 140 C14 0,539bH) K base (KS) Cupra OxA-5521 23,040i340 Low collagen content (0,32%N;2,39%C) C14 K top Cervus OxA-1941 27,600i600 C14 Layer C overl~esthe archaeolo@callevel, result Scdlments OSL QTLS-CNC1 1 27,200i2.500 Conce~~lo C mlnlmum age 74,500+ 1 1,600-1 Layer E underlies the archaeolog~callevel, result E Sed~ments OSL QTLS-CNCI 2 0,400 1s maxlmum age Test 3a, Bos (tooth 26'400+1 Gruta do Escoural U-Th SMU-248 ~owuranlum content 90~100 enamel) 0,000 Cervus (tooth 39'800+10'000-9 Test 3n. 80090 U-Th SMU-249 ~owurantum content (3.4%) enamel) ,000 Equus (tooth 48,900+5.800-5, Test 3n. 60070 U-Th SMU-250 enmel) 500 G~tada Flgueira Purellu sp 2 C14 KEN-387 30,930t700 Brava shells Cervus (tooth 30.561+11.759--1 2 U-Th SMU-232EI enamel) 0,725 Cervus (tooth 44,806+15,889-1 2 U-Th SMU-233E2 enamel) 3,958 Equus (tooth Foz do Enxarrique C U-Th SMU-225 32.93% 1,055 Average of the three results, 33,600i500 enamel) ~buus(tooth C U-Th SMU-226 34.088i800 enamel) Equus (tooth C U-Th SMU-224 34,093i920 enamel) Gruta Nova da Carbonaceous 16 (=7) C14 Gif-2703 26,400i700 Inadequate dat~ngmatenal Columbelra earth 35.876+27,299--3 7 Twth enamel U-Th SMU-235EI 54,365+22,24(+2 7 Tooth enamel U-W SMU-238EI 7.525 Carbonacwus 20 (=g) C14 Gf-2704 28,900i950 Inadequate dat~ngmatenal earth 60,927+27,405-3 8 Tooth enamel U-Th SMU-236EI 101,487+38,406- 55.919 1 JOAO ZILHAO Table 12.