Marine Radiocarbon Reservoir Effect in Late Pleistocene and Early Holocene Coastal Waters Off Northern Iberia

This is a repository copy of Marine Radiocarbon Reservoir Effect in Late Pleistocene and Early Holocene Coastal Waters off Northern Iberia. White Rose Research Online URL for this paper: https://eprints.whiterose.ac.uk/121350/ Version: Accepted Version Article: Monge Soares, Antonio M, Gutiérrez-Zugasti, Igor, González Morales, Manuel et al. (3 more authors) (2016) Marine Radiocarbon Reservoir Effect in Late Pleistocene and Early Holocene Coastal Waters off Northern Iberia. Radiocarbon. pp. 869-882. ISSN 1945-5755 https://doi.org/10.1017/RDC.2016.71 Reuse Items deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. 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[email protected] https://eprints.whiterose.ac.uk/ Radiocarbon For Peer Review MARINE RADIOCARBON RESERVOIR EFFECT IN LATE PLEISTOCENE AND EARLY HOLOCENE COASTAL WATERS OFF NORTHERN IBERIA Journal: Radiocarbon Manuscript ID RDC-RES-2016-0103.R1 Manuscript Type: Researc Article Date Submitted by t e Aut or: n/a Complete List of Aut ors: Soares, Ant)nio* Instituto Superior T+cnico, ,niversidade de Lisboa, Centro de Ci.ncias e Tecnologias 0ucleares 1C2T02 3uti+rre4-5ugasti, Igor* ,niversidad de Cantabria, Instituto Internacional de Investigaciones Pre ist)ricas de Cantabria 3on47le4-Morales, Manuel* ,niversidad de Cantabria, Instituto Internacional de Investigaciones Pre ist)ricas de Cantabria Martins, Jos+* ,niversidade de Lisboa, Instituto Superior T+cnico, Centro de Ci.ncias e Tecnologias 0ucleares 1C2T02 Cuenca-Solana, David* ,niversidad de Cantabria, Instituto Internacional de Investigaciones Pre ist)ricas de Cantabria 8ailey, 3eoffrey* ,niversity of 9or:, Department of Arc aeology Marine 14C reservoir effect, Cantabrian coast, Late Pleistocene, Early Keywords: Holocene Cambridge University Press Page 1 of 24 Radiocarbon MARINE RADIOCARBON RESERVOIR EFFECT IN LATE PLEISTOCENE AND EARLY HOLOCENE COASTAL WATERS OFF NORTHERN IBERIA António M. Monge Soares1*, Igor Gutiérrez-Zugasti2, Manuel Gonzlez-Morales2, José M. Matos Martins1, Davi Cuenca-Solana2, Geoffrey N.Bailey3 1 Campus Tecnolgico e Nuclear, Instituto Superior Técnico, Universi a e e ,isboa, .stra a Nacional 10 01m 132,34, 2525-055 Boba ela ,RS, 8ortugal. 2 Instituto Internacional e Investigaciones 8rehistricas e Cantabria, Universi a e Cantabria, . Interfacultativo, Av a. e los Castros s/n, 32005 Santan er, Cantabria, Spain For Peer Review 3Department of Archaeology, University of Yor1, King’s Manor YO1 3.8, Yor1, UK * Correspon ing author. .mail: [email protected] ABSTRACT Ra iocarbon ating of closely associate marine mollus1 shells an terrestrial material 0mammal bones or charre Aoo 4 collecte from archaeological conteBts in northern Atlantic Iberian coastal areas is use to Cuantify the marine 14C reservoir effect 0ER4 for the coastal Aaters off the Cantabrian coast 0northern Iberia4. For the first time, ER values Aere reliably etermine for these coastal Aaters an , also for the first time, a ER Aas calculate for the ,ate 8leistocene in Atlantic Iberia. 8airs of coeval samples of ifferent carbon reservoirs selecte from Upper 8aleolithic 0,ate 8leistocene4 an Mesolithic 0.arly Holocene4 conteBts yiel e ER Aeighte mean values of H113I30 14C yr an H105I21 14C yr, respectively. These values shoA oceanographic con itions characterize by a re uce offset betAeen atmospheric an surface Aater 14C contents, suggesting a noneBistent or a very Aea1 upAelling an some stratification of the Aater column. Similar oceanographic con itions have been recor e in other areas of Atlantic Iberia uring the Holocene, such as off An alusian an northAestern Galician coasts. Results not only provi e useful information on environmental con itions but also a frameAor1 to obtain more precise an reliable absolute chronologies for the ,ate 8leistocene an .arly Holocene in northern Iberia. Keywords: Marine 14C reservoir effectJ Cantabrian coastJ ,ate 8leistoceneJ .arly Holocene 1 Cambridge University Press Radiocarbon Page 2 of 24 INTRODUCTION Ra iocarbon 014C4 ates on marine samples have not been use as eBtensively as terrestrial biosphere 0charcoal or bone4 ates to set up absolute chronologies because interpretation is complicate by oceanographic factors. Nevertheless, marine shellfish Aere Ai ely use by prehistoric populations in various locations, namely in coastal areas, an their shells are abun ant an usually Aell preserve in archaeological eposits. To set up chronologies for a particular coastal area using marine samples, bac1groun research concerning the oceanographic con itions an the marine reservoir effect for the areaFor in Cuestion Peer is nee e in or Reviewer to obtain accurate an reliable results. The resi ence time of carbon in the eep ocean is about 1000 yr 0Sigman an Boyle 20004. Thus, a fraction of the 14C atoms have time to ecay 0half-lifeK5330 yr4 Ahile the eep Aater is out of contact Aith the atmosphere. The eep ocean is therefore eplete in 14C relative to the atmosphere, an the surface seaAater 0miBe layer4 also has a 14C specific activity loAer than that of the atmosphere but greater than that of the eep ocean. Marine Aaters are therefore eficient in 14C compare Aith the terrestrial biosphere an , conseCuently, marine organisms have an apparent age, the so-calle reservoir age. This reservoir age, R0t4, is efine as the ifference betAeen conventional 14C ates from a pair of coeval samples that live in ifferent carbon reservoirs 0Stuiver et al. 12854. R0t4 can vary Aith time, since the atmospheric 14C content is not constant an also varies from region to region of the ocean since the oceanographic con itions present in each region are ifferent ue to the variability in Aater mass miBtures, Ain regime, bathymetry, an upAelling of eep Aater. Consi ering these issues, Stuiver et al. 012854 mo ele the response of the Aorl ocean to atmospheric 14C variations. From this mo eling, a calibration curve for marine samples relate to the sea surface Aater 0miBe layer4 has been erive . In or er to ta1e into account the ifference in 14C content betAeen the surface Aater of a specific region an the average surface Aater, a parameter, enote as ER 0regional marine 14C reservoir effect4 an efine as the ifference betAeen the reservoir age of the miBe layer of the regional ocean an the reservoir age of the miBe layer of the average Aorl ocean at time t, is reCuire 0Stuiver et al. 12854. Usually, ER values are etermine for a particular geographical region by 14C ating of marine mollus1 shells of historic 01noAn4 age, collecte alive before 1250, i.e. of Mpre-bombM age or, perhaps more often, 2 Cambridge University Press Page 3 of 24 Radiocarbon by 14C ating of paire samples of the same age but of ifferent origin 0terrestrial an marine4. The 14C age of the terrestrial biosphere sample is then converte into a marine mo el age using the calibration curve Marine13, the most recent curve 0Reimer et al. 20134J this marine mo el age is then e ucte from the 14C age of the associate marine sample to yiel ER 0Stuiver an Braziunas 12234. Although reservoir ages are time- epen ent, ER is not accor ing Aith the mo el mentione above, unless some change of oceanographic con itions has occurre that is restricte to the regional ocean un er consi eration. This happens in regions affecte by an active upAelling of eep Aater. Rates of regional upAelling can vary in the course of time an as the intensity of 14C epletion in theFor miBe layer Peer epen s upon Reviewthe upAelling activity, it is li1ely that ER values can also vary in the course of time 0Stuiver an Braziunas 1223, Kennett et al. 1223, Ingram 1228, Ascough et al. 20054. For instance, for the Aestern 8ortuguese coast, a ER mean value of 250I25 14C yr Aas etermine for mo ern times 0AD 1880- 12404, Ahile for the perio 3000 - 500 B8 ER ta1es a mean value of 25 I 15 14C yr 0Soares an Dias 20054. On the other han , R0t4, ta1ing into consi eration its efinition mentione above, alAays ta1es a positive value, but ER can be either positive or negative 0see, for instance, Stuiver an Braziunas 1223: Fig. 15, Stuiver et al. 20154. ,arge positive ER values are usually associate Aith a strong upAelling, Ahile negative values can be associate Aith a non-eBistent upAelling an some stratification of the Aater column. 8revious research concerning the variability of ER in coastal Aaters off Atlantic Iberia alloAe the Cuantification of this parameter 0Figures 1 an 24, Ahich is of crucial importance for the correct calibration of 14C ages of marine samples. ER values Aere thus etermine for the Aestern 8ortuguese coast, Ahich Aeighte mean values are mentione above, also for Aestern an northAestern Galician coasts 0ERK H8 I12 14C yr an ERK H122 I 24 14C yr, respectivelyJ see Soares an Dias 20034, an southern Atlantic Iberian coast 0Barlavento ERK 52 I 13 14C yr, Sotavento ERK H25 I 14 14C yr, an An alusian coast ERK H108 I 31 14C yrJ see Martins an Soares 20134. So, concerning the Atlantic coasts of the Iberian 8eninsula, only the Cuantification of ER for the northern Atlantic Iberian coast 0Cantabrian Sea4 Aas missing 0see Figure 14. 3 Cambridge University Press Radiocarbon Page 4 of 24 For Peer Review Figure 1-ER Aeighte mean values for the Atlantic coasts of the Iberian 8eninsula.

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