A Revised Radiocarbon Chronology of the Aceramic Shell Midden of Ra’s Al-Hamra 6 (Muscat, Sultanate of Oman): Implication For Occupational Sequence, Marine Reservoir Age, and Human Mobility

Abstract

Ra’s al-Hamra 6 (RH-6) is one of the earliest stratified archaeological sites along the eastern littoral of the Arabian Peninsula. This shell midden was radiocarbon dated to the 6th–5th millennium cal BC, but the majority of the dates were obtained before the advent of accelerator mass spectrometry (AMS) 14C dating and suffer from large uncertainties. In addition, most of these dates were obtained on marine and mangrove shells and required correction for local variations from the global average marine 14C reservoir age (MRA). This proved difficult because no consensus value exists for this period in the area. Recent excavations at RH-6 offered the opportunity to redate this important site in order to precisely determine its occupation history and later use as a graveyard, and establish the marine reservoir effect for this time period. Thirty-eight samples of charcoal, shells, and human bone apatite were selected for 14C dating. Bayesian modeling of the 14C dates suggests that the formation of the shell midden spanned ~1 millennium, between the mid-6th and the mid-5th millennium cal BC. Positive and consistent ΔR values were calculated throughout the entire sequence, ranging from 99±27 to 207±43 14C yr. At the beginning of the 4th millennium cal BC, RH-6 was used as a graveyard, as suggested by the 14C dating of a shell in strict association with an individual buried at the surface of the site. 14C dating of human bone apatite allowed us to calculate that 89% of this individual’s diet derived from marine resources. This finding confirms previous observations showing the overwhelming presence of marine and mangrove-dwelling species in the faunal and charcoal assemblage, and implies a low mobility, or mobility restricted to the coast for this population during the 4th millennium cal BC.

First contribution of the excavation and chronostratigraphic study of the Ruways 1 Neolithic shell midden (Oman) in terms of Neolithisation, palaeoeconomy, social‐environmental interactions and site formation processes

“…For the moment, our study is based on 12 dates using combined values from the ubiquitous shells of Marcia recens and charcoal, and 12 dates using the more marine shell Lunella coronata, which are being analysed at the radiocarbon laboratory of Lyon. Preliminary results with low values of ∆R (50-150 years) strongly oscillate between the seventh and sixth millennia yr BC; these are very different from previous estimations proposed for the mid-Holocene period (240-720 years) (Staubwasser et al, 2002;Uerpmann, 1991), but closer to the robust calculations made in an archaeological context for the mid-sixth and the mid-fifth millennium cal yr BC at Ra's al-Hamra 6 where ΔR values range from 99 ± 27 to 207 ± 43 14 C yr (Zazzo et al, 2016), for the forth millennium at Ra's al-Hamra 5 (ΔR= 255 ± 55 14 C yr; Zazzo et al, 2012; or for the third millennium yr BC (Early Bronze Age) : 210 ± 15 years (Saliège, Lézine, & Cleuziou, 2005). The forthcoming results should make it possible to decide on dates for almost the entire Neolithic period.…”

The Worldwide Marine Radiocarbon Reservoir Effect: Definitions, Mechanisms, and Prospects

“…Following the code in Bronk Ramsey and Lee (), the authors employed the OxCal v4.2.3 platform (Bronk Ramsey, ) to generate a probability distribution for a Δ R value derived from marine and terrestrial samples from an archeological shellmound. This method has proved to yield results statistically equivalent to the multipair approach and has been repeated in studies involving the known‐age (e.g., Faivre et al, ) and paired (e.g., Zazzo et al, ) approaches. Translating a calibrated age range into the 14 C time scale prior to the calculation of reservoir age offsets ( R values) (an uncalibration‐convolution process) is the approach proposed by Soulet (), who argues that this method would fully account for uncertainties bounded to the radiocarbon age of the sample, the independent calendar age, and the calibration curve itself.…”

Sharks in the lagoon? Fishing exploitation at the Neolithic site of Suwayh 1 (Ash Sharqiyah region, Arabian Sea, Sultanate of Oman)

“…from different SU of the sector 3 section. As the quantification of the reservoir effect remains an unresolved problem for the region, we have chosen to recalibrate the dates obtained in the 2000s without taking into account the reservoir effect (Lindauer et al, 2017;Saliège, Lézine, & Cleuziou, 2005;Zazzo et al, 2016).…”

“…c Landsat Satellite image of the Suwayh sabkha area with the main Neolithic shell middens and the geological cores and trenches discussed in this study (modified from Berger et al, 2013; GIS simulations performed by G. Davtian, UMR CEPAM Nice, France). [Colour figure can be viewed at wileyonlinelibrary.com] Zazzo et al, 2016;Zazzo, Munoz, & Saliège, 2014), these sites are now considered to be year-long rather than seasonal occupations. Moreover, the data acquired by our studies of fish remains from another Neolithic site (RH-6) on the Omani peninsula do not permit us to highlight seasonal fishing phenomena in the region as well (Marrast, unpublished data).…”