Supported by: RFBR project #11-06-12020
Early Paleolithic cultural layers with tools of oldowan type was discovered in East Caucasus (Dagestan, Russia) by Kh. Amirkhanov (2006) and Dniester valley (Moldova) by N. Anisjutkin (2010). During last years these Paleolithic sites were studied by complex methods leading by Prof. A.L. Chepalyga, including geology, geomorphology, paleontology, palinology, sedimentology, mineralogy, paleomagnetism etc.
In Dagestan Akusha region group of Early Paleolithic sites settled in upstream of Sulak (Akusha-Usisha rivers) was studied. Numerous cultural layers with tools and bones included into layered clastic sediments.
Coverage of Akusha formation (by the name of Akusha river) divided by postsedimental erosion on 5 separate clasters (Table 1).
Table 1. Spatial characteristics of Akusha formation clusters along the Akusha-Usisha interfluves ridge.
|Clusters||Area of sediment km2 (ha)||Perimeter length (km) along the basement||Heights (asl. m);
|Thickness of sediments (m)||Oldowan sites|
|1. Muhkay - Gegalashur||0.5 (50)||3.5||1620;
|2. Ainikab-2||0.16 (16)||1.6||1555;
|3. Ainikab-1||0.01 (1)||0.430||1539;
|4. Sunduk||0.1 (10)||2||1533;
|5. Yantsara||0.01 (1)||0.5||1500;
Holostratotype of Akusha formation proposed section of site Mukhkay-2 with layered sediment 75 m thickness excavated from level 1620 to 1545 m asl. (basement). Parastratotypes proposed are in digged trenches of sites Ainikab-1,2, Mukhkay-1, Gegalashur, Sunduk. Inclination of layers to the North is near 1-2°.
Fig 1b. Transversal section of Akusha formation sediments along the Akusha-Usisha interflew ridge.
1-Akusha formation sediments area, 2 - Akusha formation eroded sediments. 3 - High asl. of Akusha formation surface. 4 - High asl. of Akusha formation basement. 5- Transversal profile along Akusha-Usisha interflew. 6- Paleolithic sites (oldovan). 7 - Digged tranche and Not yet digged tranche.
Geological age of Akusha formation was established in section Mukhkay-2 by several methods (paleontology, palinology, paleomagnetism) as Eopleistocene = Early Lower Pleistocene (0.8 – 1.8 million years). According to paleomagnetic studies this section is characterized by reverse magnetization of Matuyama epoch (0.8 – 2.6 myr). Event of normal magnetization Yaramillo (0.99 – 1.07 myr) recorded in upper part of section on depth interval 9 - 16 m. Another normal magnetization event founded some higher on the depth 3.5 m possible Kamicatsura event (0.85 myr). Some short of intervals of anomalous magnetization founded below and above of Yaramillo event (transition zones).
These data allow us to determine of isochrones of some absolute age: 0.85 myr (3.5 m depth), 0.99 (9.5 m depth), 1.07 (15 m depth). Estimated age of main cultural layer calculated by rate sedimentations 1.4 – 1.5 million years. These dating are confirmed by paleontology (Psekupsean = Odessa mammal complex).
Lithology and sediment genesis
Akusha formation represents by intercalation of coarse grain (sand, gravel, pebble, bolders) and fine sediments (clay, aulleuroclay, loam mainly carbonated). Coarse sediments have lagoonal, nearshore, proluvial, alluvial, origin and accompanied by mammal bones, tools and land mollusk shells. Fine clay sediments up to 10 m thickness reflect water basin environment relatively deep and contain nannoplankton (Spiniferites ramosus, Spiniferites sp. Panonean type) typical for brackish water Caspian type isolated brackish basins (Apsheronean, Akchagylean)..
Clay packages contain mineral authigene glauconit which formed during sedimentations time. This suggest of isolated marine basin nearshore environment. This time in the Caspian depression (30 km from Akusha sites) was Apsheronean brackish water basin. Possible, Akusha formation sediments deposited in lagoons of this basin (See picture).
Palinological studies of upper 35 m thickness sediments recovered vegetation changes with 13 palinocomplexes and reflects alteration of climatic oscillations (aridisation – humidisation, cooling - warming). During cooling stages parvifoliate (Betula) and dark coniferous (Picea, Tsuga) are predominate; warming stages accompanied by thermophile timber (Magnolia, Ostrya, Pterocaria, Cryptomeria) and just absence of dark coniferous and parvifoliate.
First human settlements appeared on low hights of Caucasus foothills and nearshore environment possible faced to Apsheronean basin subjected by sea level oscillations. Coarse sediment accumulation is indicator of regressive stages of the basin. Territory was covered by terrestrial landscape with broad live vegetation contained thermophil elements and settled by Psekupsean mammal complex. Oldowan type of tools were used by archanthropes. Fine clay sediments accumulation reflected transgressive stages and sea level rise, water basin deeped and flooded previously terrestrial landscape with human population. During next 1.0 - 1.5 ma this territory was rised on 1-1.5 km by tectonic uplift and reached resent mountain level.
Dniester valley (Dubossary town, Moldova)
Early Paleolithic site Bayraki discovered by Dr. N.K. Anisjutkin (IMC RAS, Russia) in 2010, settled in alluvial and cover beds of VII Dniester terrace (Lower Eopleistocene). The same time it was studied by A.L. Chepalyga for age and environmental reconstruction determination. River Dniester alluvial terraces system near Dubossary town is studied and corrected. 5 high terraces system represented by: three terraces – VIII, VII, VI (Eopleictocene age) with artefacts and 3 terraces – VI high, VI low, V (Early Neopleictocene) were investigated. Paleomagnetic event Yaramillo (0.98-1.07 mln. years) was found in stratotype section Chitskany terrace in upper alluvium of VII terrace. This date supported by RTL dates 1.1 mln. ±0,25 and 0.940 ±0,2 mln. years and Tamanean complex of mammals (Epivilafranchean). The age of the oldest oldovanean tools from alluvial pebble is 0.8 – 1.2 mln years. This is one of the oldest Early Paleolithic site in the Europe. Fossil soils and pedosediments are studied: 3 fossil soils were identified. Palinologycal analysis recovered some palinozones with forest (oak, beech, hornbeam, elm, linden, hazel, etc.) and steppe vegetation. Climatic environment is reconstructed.
Fig. 4. Terrace profile of Dniester valley near Dubossary town and stratigraphic position of Early Paleolithic sites.