Obi-Rakhmat Grotto

The Obi-Rakhmat Grotto is a Middle Paleolithic prehistoric site that yielded Neanderthal fossils. It is a shallow karst cave near the junction of the Chatkal and Pskem Rivers at the southwestern end of the Talassky Alatau Range in the Tien Shan Mountains, 100 km (62 mi) northeast of Tashkent, Uzbekistan.

Obi-Rakhmat Grotto
Obi-Rakhmat Grotto is located in Continental Asia
Obi-Rakhmat Grotto
Shown within Uzbekistan
Obi-Rakhmat Grotto is located in Uzbekistan
Obi-Rakhmat Grotto
Obi-Rakhmat Grotto (Uzbekistan)
Obi-Rakhmat Grotto is located in West and Central Asia
Obi-Rakhmat Grotto
Obi-Rakhmat Grotto (West and Central Asia)
LocationTalassky Alatau Range
RegionTien Shan Mountains
Coordinates41°34′08.8″N 70°08′00.3″E
Altitude1,250 m (4,101 ft)
Length20 metres (66 ft)
Width9 metres (30 ft)
Height11.8 metres (39 ft)
History
Materiallimestone
PeriodsMiddle Paleolithic
Associated withNeanderthals
Site notes
Excavation dates1962
ArchaeologistsM. M. Gerasimov, H. K. Nasretdinov

Excavations

The Obi-Rakhmat Grotto was discovered in 1962 by a team from the Institute of History and Archaeology of Uzbekistan, headed by A. R. Mukhamedzhanov. Initial excavations were carried out under the supervision of M. M. Gerasimov and H. K. Nasretdinov and from 1964 to 1965 by R. H. Suleimanov. An international multidisciplinary team resumed excavations in 1998 under the direction of Anatoly Derevyanko, Andrei Krivoshapkin and Patrick Wrinn.[1]

Stratigraphy

The cave is 9 m (30 ft) long, 20 m (66 ft) wide at the entrance and 11.8 m (38.71 ft) high and sitting at an elevation of 1,250 m (4,100 ft),[2]

The sequence of deposits has a depth of about 10 m (33 ft) and divides into 22 stratigraphic units, based on texture and archaeological content. The rich assemblages of lithic artifacts suggest prolonged Neanderthal occupation.

  • Artefacts: core-burins on large flakes, unidirectional blade and flake cores, (mostly retouched blades and retouched pointed blades, while other common types include burins, atypical end scrapers, sidescrapers (grattoir de côté) and Mousterian points) and Levallois forms. The Levallois forms are concentrated in the basal layers, especially stratum 19. The principal raw material is local petrified limestone.

Obi-Rakhmat's tool industry differs in only minor ways from the classic and elongated Levallois points of Kara-Bom. Obi-Rakhmat's finds share features of both the late Middle Paleolithic and the early Upper Paleolithic artifacts of Southwest Asia and the Altai Mountains. It appears that the Upper Paleolithic in the Altai emerged from a local Middle Paleolithic culture established in the area around 100,000 to 50,000 years ago. Based on material of the most recent excavations from 2007 to 2009 there is reason to assume that the Obi-Rakhmat lithic artefacts represent a transitional Middle-to-Upper Paleolithic industry.[3]

Stratum 19 seems to represent a series of exceptionally intensive occupational episodes because of the high density of finds and the presence of charcoal, burnt bones and artefacts.[2][1]

Chronology

(Uranium-thorium datings of travertine sediments range between 70,000–100,000 years BP. These results are less secure due to the high uranium content and the presence of detritus, which contaminates dated sediments. ESR analysis of tooth enamel for eight Bovidae give an age estimation of ca. 57,000 to 73,000 years BP (strata 12–14) and ca. 87,000 years BP (basal stratum 21.1). The preliminary results of OSL dating on sediments from several profile locations gave uniform ages for all cultural successions: stratum 5.1 (56,000 ± 3200 years), stratum 8.1 (60,100 ± 3000 years), and stratum 21.2 (61,400 ± 3600 years):[3]

Parts of the sequence is beyond the limit of sensitivity of the C14 dating method. However layer 9, dated to 42,100 years BP is well within the limit. Possibly, the age of layer 14.1 (48,800 years BP) may be a minimal estimate, but more study is necessary to precisely determine the age. The true age of layer 14 at Obi-Rakhmat site is still open to discussion.[3][4]

Fauna

The faunal assemblage is dominated by the Siberian mountain goat (Capra sibirica) and red deer (Cervus elaphus), which constitute 90% of the identified fossils. Other faunal remains include sheep (Ovis sp.), wild boar (Sus scrofa), fox (Vulpes vulpes) and marmot (Marmota sp.). Carnivore remains are rare.

Evidence of human modification of the bones including cut marks, conchoidal impact, scars and burning, is consistently present. The lithic artefacts and faunal remains recovered at Obi-Rakhmat suggest that the site was repeatedly used by hominins as a short-term hunting and butchery station.[2]

Hominin remains

OR 1

In 2003, hominin remains were recovered from stratum 16. They consist of 6 isolated permanent upper teeth and 121 cranial fragments from a single juvenile.[5]

Morphology

Six isolated permanent teeth were found. They consisted of an upper lateral incisor, upper third premolar, upper fourth premolar, upper first molar, and an upper second molar, as well as 121 cranial fragments. All of the teeth found had complete crowns with developed roots. The varying size of the roots in each tooth make it difficult to determine if they are damaged, or the length they are because of development. It was determined that all of the pieces belonged to a 9-12-year-old juvenile. The sex of this particular fossil remains unknown. The teeth found have Neanderthal features, as some of them show Taurodontism, which is primarily found in the Neanderthal morphology. Studies of the pieces of cranium found are more ambiguous and harder to link to Neanderthals. The Parietal bone has a stronger likeness to anatomically modern humans, while other bones of the skull can be linked to Neanderthal craniums. Most researchers believe that this particular fossil is a Neanderthal because of the analysis of its dentition.

The Obi-Rakhmat fossil expresses a relatively Neanderthal-like dentition coupled with more ambiguous cranial anatomy (e.g., its parietal size and aspects of the external surface of its temporal) that does not conform to existing descriptions of sub-adult Neanderthals. It represents an individual of roughly 9 to 12 years of age at death, estimated from the examination of relative root development and degree of dental wear.[5]

The sub-adult bone yielded non-calibrated dates ranging from 29,990 ± 500 years BP to 37,800 ± 450 years BP.[6] To date, the best chronological estimate for the hominid remains from Obi-Rakhmat is ca. 60,000 to 90,000 years BP [5] and 70,000 years BP.[7]

DNA analysis

The mitochondrial DNA (mtDNA) sequences from the Obi-Rakhmat sub-adult (OR-1) and Teshik Tash child fall within the European Neanderthal mtDNA variation, showing that both individuals belonged to a population related to European and western Asian Neanderthals. However, the Teshik Tash mtDNA sequence seems to be more closely related to the mtDNA sequence from Scladina in western Europe than to the sequence from Okladnikov Cave. The absence of deep mtDNA divergence shows that Central Asian, Caucasian and European Neanderthals were not separated for a long time, supporting the view that Central Asia (most of the Russian plains) was relatively recently colonized by Neanderthals, maybe not before an exceptionally warm episode 125,000 years ago.[6]

See also

References
  1. Andrei I. Krivoshapkin and P. Jeffrey Brantingham, The Lithic Industry of Obi-Rakhmat Grotto, Uzbekistan "The Lithic Industry of Obi-Rakhmat Grotto, Uzbekistan" (PDF). Archived from the original (PDF) on April 22, 2006.. In: Actes du XIV Congres UISPP, 2–8 septembre 2001. BAR International 1240: 203-214
  2. Carolina Mallol, Susan M. Mentzer and Patrick J. Wrinn, A Micromorphological and Mineralogical Study of Site Formation Processes at the Late Pleistocene Site of Obi-Rakhmat, Uzbekistan"ineralogical Study of Site Formation Processes at the Late Pleistocene Site of Obi-Rakhmat".. Geoarchaeology: An International Journal, Vol. 24, No. 5, 548–575 (2009). Published online in Wiley Interscience (www.interscience.wiley.com). DOI:10.1002/gea.20280
  3. Andrei I Krivoshapkin, Yaroslav V Kuzmin, A J Timothy Jull, Chronology of the Obi-Rakhmat Grotto (Uzbekistan): First Results on the Dating and Problems of the Paleolithic Key Site in Central Asia "First Results on the Dating and Problems of the Paleolithic Key Site in Central Asia".. Proceedings of the 20th International Radiocarbon Conference, edited by A J T Jull. RADIOCARBON, Vol 52, Nr 2–3, 2010, p 549–554
  4. Andrei I Krivoshapkin, Yaroslav V Kuzmin, A J Timothy Jull, Chronology of the Obi-Rakhmat Grotto (Uzbekistan): First Results on the Dating and Problems of the Paleolithic Key Site in Central Asia. Proceedings of the 20th International Radiocarbon Conference, edited by A J T Jull. RADIOCARBON, Vol 52, Nr 2–3, 2010, p 549–554. p 553]
  5. Michelle Glantz, Bence Viola, Patrick Wrinn, Tatiana Chikisheva, Anatoly Derevianko, Andrei Krivoshapkin, Uktur Islamov, Rustam Suleimanov, Terrence Ritzman, New hominin remains from Uzbekistan Glantz, Michelle; Viola, Bence; Wrinn, Patrick; Chikisheva, Tatiana; Derevianko, Anatoly; Krivoshapkin, Andrei; Islamov, Uktur; Suleimanov, Rustam; Ritzman, Terrence (2008). "New hominin remains from Uzbekistan". Journal of Human Evolution. 55 (2): 223–237. doi:10.1016/j.jhevol.2007.12.007. PMID 18499228.. Journal of Human Evolution 55 (2008) 223–237. doi:10.1016/j.jhevol.2007.12.007 "New hominin remains from Uzbekistan". for free
  6. Johannes Krause, Ludovic Orlando, David Serre, Bence Viola, Kay Prüfer, Michael P. Richards, Jean-Jacques Hublin, Catherine Hänni, Anatoly P. Derevianko & Svante Pääbo, Neandertals in Central Asia and Siberia Krause, Johannes; Orlando, Ludovic; Serre, David; Viola, Bence; Prüfer, Kay; Richards, Michael P.; Hublin, Jean-Jacques; Hänni, Catherine; Derevianko, Anatoly P.; Pääbo, Svante (2007). "Neandertals in Central Asia and Siberia". Nature. 449 (7164): 902–904. Bibcode:2007Natur.449..902K. doi:10.1038/nature06193. PMID 17914357. S2CID 2084412.
  7. Anne R. Skinner, Bonnie A.B. Blackwell, Abubakar Mian, Shauntè M. Baboumian, Joel I.B. Blickstein, Patrick J. Wrinn, A.I. Krivoshapkin, A.P. Derevianko, Joyce A. Lundburg, ESR analyses on tooth enamel from the Paleolithic layers at the Obi-Rakhmat hominid site, Uzbekistan: Tackling a dating Skinner, Anne R.; Blackwell, Bonnie A.B.; Mian, Abubakar; Baboumian, Shauntè M.; Blickstein, Joel I.B.; Wrinn, Patrick J.; Krivoshapkin, A.I.; Derevianko, A.P.; Lundburg, Joyce A. (2007). "ESR analyses on tooth enamel from the Paleolithic layers at the Obi-Rakhmat". Radiation Measurements. 42 (6–7): 1237–1242. doi:10.1016/j.radmeas.2007.05.033.. Proceedings of the 7th International Symposium on EPR Dosimetry and Applications and the 2nd International Conference on Biodosimetry. Radiation Measurements; Volume 42, Issues 6–7, July–August 2007, Pages 1237–1242
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