Accelerator Radiocarbon Dating of the Initial Upper Palaeolithic in Southeast Siberia

Article excerpt

Introduction

The timing of the Middle to Upper Palaeolithic transition (Binford 1989; Klein 1992; Knecht et el. 1993; Mellars 1989a; 1989b; White 1982) is not entirely clear, since it lies at or just beyond the limit of radiocarbon (14C) dating, 5030,000 years ago (b.p.). Until recently, the earliest Upper Palaeolithic was thought to date to 35,000 b.p. (Gamble 1986: 245; Mellars et el. 1987: 128; Straus & Heller 1988: 99), but AMS 14C, thermoluminescence and uranium-series dating methods now show that the earliest Upper Palaeolithic in Europe and the Levant emerged as early as 40,000 b.p. (Bar-Yosef et el. 1992: 517; Bischoff et el. 1989; Hedges et el. 1990; Mellars 1993; Valdes & Bischoff 1989).

New dates also change the timing of the transition in Inner Asia. At Kara-Bom, southwest Siberia, AMS 14C determinations from a basal Upper Palaeolithic occupation demonstrate that the transition occurred as early as 45,000 b.p., at least 8,000 years earlier than previously thought (Goebel et al. 1993). The new AMS 14C determinations presented in this report, from two sites in southeast Siberia, confirm the Kara-Bom findings. The Middle to Upper Palaeolithic transition in Inner Asia occurred as early as it did in Europe and southwestern Asia possibly even earlier.

The sites

Makarovo-4

Makarovo-4 is a single-component open-air site located along the upper Lena River, 8 km northwest of the village of Kachug, Irkutsk Oblast', Russia [ILLUSTRATION FOR FIGURE 1 OMITTED] (53 [degrees 56 [minutes] N, 105 [degrees] 50 [minutes] E), and discovered by Aksenov (1978; 1989a; 1989b) in 1975. In excavations conducted from 1975 through 1982 an area of about 1100 sq. m was exposed, and over 4000 artefacts were recovered (Aksenov 1989a; 1989b; Medvedev et al. 1990).

The site is situated along the south-facing bluff of a side-valley alluvial fan (called the fourth terrace by Tseitlin (1979: 199)), 40 m above the right bank of the Lena River (Aksenov 1989b; Vorob'eva 1987: 19). Its Quaternary stratigraphy has a series of colluvial and aeolian loams and sandy loams divisible into four sets of sediments [ILLUSTRATION FOR FIGURE 2 OMITTED] (Aksenov 1989b; Tseitlin 1979: 197-8; Vorob'eva 1987). Set 4, at the base of the exposed profile, is a series of interbedded, colluvial sands, sandy loams, silts, and clays with abundant rock inclusions. Set 3 consists of two subunits, a 1.5-m thick bed of highly carbonate-cemented loess-like loam containing a distinct palaeosol (3b) overlain by a 3- to 10-cm thick band of sand and rock debris (3a). Set 2 includes interbedded layers of sand and highly carbonate-cemented loess. Set 1, the top 40-60 cm of the profile, consists of a loam masked by an early Holocene (?) palaeosol and modern soil horizons.

Early Upper Palaeolithic artifacts at Makarovo-4 occur along the surface of Set 3a, which has undergone considerable post-depositional deformation (Aksenov 1989a: 125; Aksenov & Naidentskaia 1979). Set 3a appears to be a lag deposit left behind after finer sediments had been deflated by intense, high winds. Many lithic artefacts and faunal remains lying on the surface of this lag deposit are polished from sand-blasting. Winds probably blew smaller artefacts across the site away from main activity areas, and solifiuction moved artefacts down the 6 [degrees] slope the site lies upon. A series of ice-wedge pseudomorphs breach the cultural component, forming a network of polygons that extend across the site.

This complex geologic context makes dating the Makarovo-4 cultural occupation difficult. Tseitlin (1979) originally placed the deflation event of Set 3a into a glacial interval when the upper Lena valley was cold, dry and windswept. If Set 2 sediments record the last glacial maximum (oxygen-isotope stage 2), as Aksenov (1989b), Tseitlin (1979) and Vorob'eva (1987) concur, then the deflation of Set 3a and the sand-blasting of the lithic artefacts and bone must have taken place during an earlier glacial period. …