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Archaeol. Oceania 44 (2009) 160–168 Research Reports Marine reservoir corrections for Moreton Bay, Australia SEAN ULM, FIONA PETCHEY and ANNIE ROSS Keywords: DR, marine reservoir effects, marine shell, radiocarbon dating, Moreton Bay Abstract We present the first direct assessment of marine reservoir effects in the Moreton Bay region using radiocarbon dating of known-age, pre-AD 1950, shell samples from the east coast of Stradbroke Island and archaeological shell/charcoal pairs from Peel Island in Moreton Bay. The resulting DR value of 9±19 14C years for the open ocean conforms to regional values established for northeast Australia of 12±10 14C years. Negative DR values of –65±61 14C years and –216±94 14C years for southern Moreton Bay highlight the potential for larger offsets over the last ~900 years. These may be linked to changing terrestrial inputs and local circulation patterns. Shells and other organisms that have grown in marine environments exhibit older apparent radiocarbon ages caused by the uptake of carbon which has already undergone radioactive decay through long residence times in the deep ocean. On average, the ocean surface (<200 m) has an apparent 14C age around 400 years older than the atmosphere (Gillespie and Polach 1979; Stuiver et al. 1986). However, studies worldwide have shown that variation in 14C activity in near-shore marine and estuarine environments depends greatly on local and regional factors, such as hinterland geology, tidal flushing and terrestrial water input (e.g. Dye 1994; Southon et al. 2002; Stuiver and Braziunas 1993). Regional differences in marine reservoir effect are most commonly determined through radiocarbon dating pre-AD 1950 known-age marine specimens (e.g. shell, coral, otoliths) (e.g. Bowman and Harvey 1983; Gillespie and Polach 1979; Southon et al. 2002) or dating shell and charcoal paired samples from contemporaneous archaeological contexts (e.g. Gillespie and Polach 1979; Ulm 2002). The marine reservoir effect is conventionally expressed as DR, which is the difference between the conventional radiocarbon age of a sample of known-age from a specific locality and the equivalent age predicted by the global modelled marine calibration curve (Hughen et al. 2004; Stuiver et al. 1986). Moreton Bay is a large, shallow, subtropical, semi-enclosed triangular embayment formed between the large sand islands of Stradbroke and Moreton Islands and the mainland coastline of Australia (Figure 1). The bay extends c.90 km north-south and c.30 km east-west and contains some 360 islands. Radiocarbon dating of marine samples from Moreton Bay forms the basis of archaeological and geomorphological chronologies used to model changes in Aboriginal occupation (McNiven 2006; Ulm and Hall 1996), sea-level change (Flood 1981, 1984; Lovell 1975), the development of fringing coral reef systems (Hekel et al. 1979: 17; Ward et al. 1977) and the establishment of intertidal and subtidal shellfish communities (Flood 1981: 21; Hekel et al. 1979: 9). However, despite a heavy reliance on radiocarbon marine shell ages to construct archaeological and geomorphological chronologies, there has been no systematic evaluation of the local applicability of the generalised marine reservoir value for ocean surface waters in the region. Radiocarbon ages obtained on contemporaneous terrestrial and marine samples are not directly comparable. SU: Aboriginal and Torres Strait Islander Studies Unit, University of Queensland, Brisbane, Qld 4072, s.ulm@uq.edu.au; FP: Radiocarbon Dating Laboratory, University of Waikato, Hamilton 3240, New Zealand; AR: School of Social Science, University of Queensland, Brisbane, Qld 4072 and School of Natural and Rural Systems Management, University of Queensland, Gatton, Qld 4343. 160 Figure 1. Moreton Bay, showing approximate position of the shoreline at 6000 BP (after Hekel et al. 1979: 8; Jones 1992: 31). Marine and estuarine reservoir differences are a major issue in the investigation and dating of coastal archaeological and geomorphological deposits where these factors can result in calibration errors of up to several hundred years. For central Queensland a local open ocean DR of 11±10 14C years has been established; but values for adjacent estuaries diverge significantly with values of up to DR= –155±55 14C years documented (see Ulm 2002 for detailed discussion). In this case, the blanket application of the regional DR value would produce calibrated ages approximately 200 years too young. In the absence of local studies of marine reservoir effects, researchers in the Moreton Bay region have either reduced marine 14C ages by a generic Australia-wide 450±35 14C years recommended by Gillespie and Polach (1979) (e.g. Flood 1984) or adopted the northeast coast DR value c.12±10 14C years recommended by Ulm (2006) and Reimer and Reimer (2008) (e.g. McNiven 2006). For well-equilibrated open waters in the Eastern Australian Current the northeast coast value is likely to approximate local open ocean values, but studies elsewhere suggest that the waters within embayments like Moreton Bay itself could reflect local input and hydrological conditions (e.g. Little 1993). As a preliminary assessment of the potential impact of marine carbon variability in the Moreton Bay region, two marine shells live-collected in 1902 and two shell/charcoal paired samples from archaeological contexts were radiocarbon dated to determine local marine and estuarine reservoir values. Previous DR research in the Moreton Bay region Gillespie and Polach (1979: Table 5; see also Gillespie 1977: Table 4) reported two determinations on shells livecollected in 1973 from Macleay Island in southern Moreton Bay as part of a broader study of the suitability of dating marine shell (Figure 1, Table 1). Differences in the radiocarbon activity (expressed as pMC) may be taken as a general indication of variation in 14C activity of source waters and therefore also local and regional oceanographic processes (Hogg et al. 1998). The two determinations show good agreement and are slightly lower than those reported for contemporaneous open water coral cores off the central Queensland coast from Lady Musgrave Island (111.95±0.21 pMC), Heron Island (112.45±0.21 pMC) and Abraham Reef (111.13±0.21 pMC) (Druffel and Griffin 1995). These data are difficult to interpret, however, because of the absence of any regional modelling of post-AD 1950 alteration to the marine carbon reservoirs resulting from nuclear detonations (Reimer et al. 2004). Nonetheless, they suggest the possibility of a lag in registering a peak marine bomb signature in Moreton Bay compared to the wellequilibrated waters of the western Pacific Ocean. The selection of the whelk Pyrazus ebeninus, a grazing gastropod, could be problematic because this shellfish may have ingested carbon from a variety of sources, including 14C depleted peats (cf. Keith et al. 1964). Additionally, whole shells were dated which, as Gillespie and Polach (1979: 414) acknowledge, provides an average 14C signature over the growth period of the shell. M. edulis can live up to 24 years (Powell and Cummins 1985: Table 1), while most gastropods live <5 years (Frank 1969: 247). This ‘inbuilt age’ may be critical in the rapidly changing post-bomb environment. Site Lab. No. Sample Diet Historical pMC Age (F14C%) (year AD) SF 1973 105.9±0.8 Macleay SUA-218/1 Mytilidae: Island Mytilus edulis planulatus Macleay SUA-218/2 Batillariidae: H Island Pyrazus ebeninus 1973 104.6±0.8 Table 1. Post-AD 1950 live-collected shell (Gillespie and Polach 1979: Table 5). SF = suspension-feeder. H = herbivore. pMC (Percent Modern Carbon) represents the proportion of 14C atoms in the sample compared to that present in AD 1950 (Stuiver and Polach 1977). Materials and methods Two known-age, pre-AD 1950 shell samples and two archaeological shell/charcoal paired samples provide our data. All shell samples are suspension-feeding bivalves which are considered the most reliable sample material for DR studies (Hogg et al. 1998; Forman and Polayak 1997). Pre-AD 1950 known-age shells Two valves of the pipi Donax (Plebidonax) deltoides (Lamarck, 1818) from different individuals were dated (Table 2). Kesteven (Walker 1983) collected these samples from the ‘outer beach’ of North Stradbroke Island (Figure 1) in September 1902 and they were presented to the Australian Museum by Charles Hedley (Australian Museum Reg. No. C13037). The collection date is equivalent to a model marine age of 452±23 14C years. D. deltoides is a short-lived (<4 years), shallow-burrowing, suspensionfeeding littoral sand dweller on high energy surf beaches (Beesley et al. 1998: 346-8; King 1976, 1985; Lamprell and Whitehead 1992; Murray-Jones 1999). A 5 mm cross-section was removed perpendicular to the edge of each shell across multiple increments of growth to avoid intra-shell variations in 14C (Culleton et al. 2006) and provide an average value for the shell margin (i.e. to approximate the time of death as closely as possible). Sample preparation for accelerator mass spectrometry (AMS) determinations (including CO2 production) was undertaken by the University of Waikato Radiocarbon Dating Laboratory. AMS dating was conducted by the Rafter Radiocarbon Laboratory of the New Zealand Institute of Geological and Nuclear Sciences (IGNS). d18O and d13C values were measured on gas splits taken during preparation 161 of samples for AMS analysis at the University of Waikato using a Europa Scientific Penta 20-20 isotope ratio mass spectrometer. To calculate DR, the historical age of each shell sample (i.e. year of death) was converted to an equivalent global marine modelled age using the MARINE04 calibration dataset (Hughen et al. 2004). DR values were calculated by deducting the equivalent global marine model age at the time of death of the shell sample from the conventional radiocarbon age obtained (Stuiver et al. 1986). DRs is the one-sigma estimate of uncertainty in the conventional radiocarbon age of the shell sample. Archaeological shell/charcoal pairs Two shell/charcoal paired samples were dated from the Lazaret Midden located on the north margin of Peel Island in southern Moreton Bay (Figure 1, Table 3) (Ross 2001; Ross and Coghill 2000; Ross and Duffy 2000). Excavation of four 50 x 50 cm squares revealed a dense deposit of shell and fish bone spanning the last c.1200 years. The pairs are associated with hearth features, providing secure stratigraphic contexts for the samples. Charcoal samples were paired with valves of the short-lived (<10 years) Trichomya hirsutus, a suspension-feeding mussel which lives attached to substrata in the lower intertidal to upper subtidal zone (Beesley et al. 1998: 251; Creese et al. 1997: 230). A key limitation of DR studies employing archaeological marine/atmospheric samples is the assumption that the paired samples are contemporaneous. The difficulty of identifying such samples and the lack of independent age confirmations has led to scepticism over marine reservoir values calculated in this way (e.g. Gillespie and Polach 1979; Petchey and Addison 2005: 79). The Lazaret Midden pairs presented here are from apparently secure stratigraphic contexts without obvious post-depositional disturbance, were collected from the same small excavation units and conform to the age-depth sequence for the site (excluding the disturbed surface layer, see Prangnell 2002: 35). In the absence of other information the samples are assumed to be coeval. Whole shells were dated by conventional liquid scintillation counting undertaken by the University of Waikato Radiocarbon Dating Laboratory and Beta Analytic Inc. DR values for pairs were calculated by converting the charcoal 14C age to the equivalent global marine model age using atmospheric ages interpolated from SHCal04 (McCormac et al. 2004) to the same calendar year as MARINE04 (Hughen et al. 2004) (for procedure see Reimer et al. (2002) and Ulm (2002)). The intersections of the oneSite Museum No. Lab. No. Sample Stradbroke Island Stradbroke Island C13037/3 Wk-17806 C13037/4 Wk-17807 Donacidae: SF D. deltoides Donacidae: SF D. deltoides sigma range of the conventional radiocarbon age of the atmospheric (charcoal) sample with the MARINE04 calibration curve, interpolated between available data points, provided maximum and minimum marine model ages. The midpoint of these values was taken as the model marine age. The estimated uncertainty in the marine model age includes both the range of the maximum and minimum marine model ages and an estimate of the average uncertainty of the atmospheric calibration data in the onesigma range of the atmospheric age. DR was calculated by deducting the marine model age of the atmospheric determination from the conventional radiocarbon age of the paired marine shell sample. DRs includes the estimated uncertainty in the marine model age and the marine radiocarbon age. For an alternative method using samplebased Bayesian inference that allows uncertainty in the dated events to be incorporated see Petchey et al. (2005) and Jones et al. (2007). Results Results are presented in Tables 2–4 and Figure 2 and outlined below. Pre-AD 1950 known-age shells AMS dating of the two samples of D. deltoides collected in 1902 returned radiocarbon ages of 478±23 BP (Wk-17806) and 443±23 BP (Wk-17807) which are equivalent to DR=26±23 14C years and –9±23 14C years respectively (Table 2). The two ages are indistinguishable with an errorweighted mean of 461±17 14C years, equivalent to DR=9±19 14C years (Table 4). Archaeological shell/charcoal pairs The two shell/charcoal pairs from archaeological contexts returned DR values of –65±61 14C years and –216±94 14C years which combine to yield an error-weighted mean with additional variance of –110±94 14C years (Table 4). This value cannot be distinguished from the local open ocean value of DR = 9±19 14C years presented above owing to the large uncertainty estimate. These results suggest that DR activity in the last 500 years approximated modern values, but with the possibility of a shift to more negative values in the last millennium indicated by the –216±94 value around 850 years ago (Figure 2). The pooling statistics (Table 4) are based on Mangerud et al. (2006: 3241) where the Chi squared (x2) test is used to Diet Historical Age (year AD) September 1902 September 1902 d 13C (‰) d 18O (‰) CRA (BP) Equivalent Marine Model Age ∆R (14C yr) 1.1±0.2 0.09±0.06 478±23 452±23 26±23 0.7±0.2 –0.64±0.06 443±23 452±23 –9±23 Table 2. ∆R values from known-age pre-AD 1950 shells from Stradbroke Island. SF = suspension-feeder. 162 ∆R (14C yr) Site Square/ Depth Lab. No. XU (mm) Sample Diet d 13C (‰) d 18O (‰) CRA (BP) Equivalent Marine Model Age Lazaret Midden Lazaret Midden B4/12 B4/12 300 300 Wk-8009 Wk-8013 – SF –27.2±0.2 0.7±0.2 – –1.36±0.06 500±50 840±50 905±35 840±50 –65±61 Lazaret Midden Lazaret Midden A/10 A/10 270 270 Beta-98031 Beta-98032 charcoal Mytilidae: T. hirsutus charcoal Mytilidae: T. hirsutus – SF –25e±2e 1e±2e – – 970±60 1090±60 1306±72 1090±60 –216±94 Table 3. ∆R values from paired shell/charcoal samples from the Lazaret Midden, Peel Island. e=estimated value only. Description No. ∆R Pooled (14C years) x2 Test x 2/(n-1) ∆R with External Variance (14C years) Stradbroke Island known-age Lazaret Midden archaeological Known-age and archaeological 2 2 4 9±16 -110±51 -2±16 T'=1.16; x21:0.05 =3.84 T'=1.82; x21:0.05 =3.84 T'=7.82; x23:0.05 =7.82 1.16 1.82 2.61 9±19 -110±94 -2±103 Table 4. DR pooling statistics. test the internal variability in a group of ∆R values. If x2/(n-1) is >1 the group has additional variability beyond measurement uncertainties, and the additional variance (sext) and uncertainty are calculated and applied to the ∆R. The additional variance (sext) is obtained by subtracting the 14C measurement variance from the total population variance and obtaining the square root; therefore sext=√(s2pop–s2meas). Any uncertainty including additional variance is calculated by √(E2∆Rpooled+s2ext). When x2/(n-1) is ≤1 the weighted mean is used (see Mangerud et al. 2006: 3241-2 for details). Discussion The local open ocean value of ∆R = 9±19 14C years calculated for samples from Stradbroke Island conforms with expectations derived from calculations of ∆R in open ocean contexts to the north, confirming the general uniformity of marine reservoir effects in areas dominated by the Eastern Australian Current (Figure 2). The two negative ∆R values from Peel Island within Moreton Bay of –65±61 14C years and –216±94 14C years, while not significantly different owing to the large error estimates, indicate enrichment of the local marine reservoir relative to the modelled surface ocean (Hughen et al. 2004). A range of factors that could contribute to these values are discussed below. Hydrology and circulation patterns Moreton Bay is dominated by semi-diurnal tides entering the bay through the northern opening and three smaller ⊳ Figure 2. Moreton Bay ∆R plotted against the knownage of live-collected samples and the median of the calibrated age-range of terrestrial samples in archaeological pairs. Vertical error bars represent the estimated error in ∆R values and horizontal bars represent the 1s spread in the calibrated age-ranges. The shaded zone shows the regional ∆R value of 12±10 14C years recommended for the northeast Australia (Ulm 2006). Radiocarbon ages on terrestrial samples in archaeological pairs were calibrated to calendar years using OxCal 4.0 (Bronk Ramsey 1995, 2001) and the SHCal04 dataset (McCormac et al. 2004). The median calibrated age takes account of the irregular probability distribution of calibration results (Telford et al. 2004). 163 passages along the eastern margin at South Passage, Jumpinpin and Southport Bar (Figure 1). Although tidal flushing is generally high, with average residence time estimated at 50 days, there is marked variability in tidal exchange between the deep northern section and the poorly flushed shallow southern section which exhibits residence times in excess of the overall bay average (Gabric et al. 1998). High annual rainfall (1500 mm), a large catchment (18,000 km2) and occasional cyclone events are responsible for large periodic freshwater inputs, depressing salinity and introducing large volumes of dissolved atmospheric CO2 (Gabric et al. 1998; Milford and Church 1977). Dissolved inorganic carbon may also be introduced from groundwater discharge, including through swampy peat environments, along the margins of Stradbroke Island (Hadwen 2006). We have attempted to differentiate between these sources using d13C and d18O isotopic information where available. d18O is a highly sensitive indicator of change in water temperature and salinity, while the d13C value of marine shells is thought to predominantly reflect changes in water source and overall marine productivity (Culleton et al. 2006; Kennett et al. 1997). Marine carbonates have high d13C values c.0±2‰ (Stuiver and Polach 1977: 358), whereas freshwater values are typically depleted 5–10‰ compared to mean ocean water (Keith et al. 1964). Marine shellfish which incorporate a significant proportion of carbon derived from plant or soil sources should exhibit d13C values lower than that expected of marine environments. However, the d13C value available for T. hirsutus (Wk-8013) of 0.7±0.2 per mil is well within the range expected for marine samples (Stuiver and Polach 1977: 358), suggesting little input from terrestrial carbon sources. Conversely, the d18O value for Wk-8013 (–1.36 ‰) is more depleted than the open ocean marine shells from Stradbroke Island (0.09 and –0.64‰) as would be typical for less saline waters (Culleton et al. 2006: 390; Dettman et al. 2004; Keith et al. 1964). Although the data are too limited to draw any firm conclusions, a similar discrepancy in d13C values has been noted by Spiker (1980) where photosynthetic activity enhances isotope exchange with atmospheric CO2 resulting in more positive d13C values than is typical for estuarine waters (see also Petchey et al. 2008). The combination of high freshwater inputs, well-aerated shallow waters and poor tidal flushing extending residence times might help explain the observed ∆R values. Forman and Polyak (1997: 888) have argued that increased wind turbulence may augment transfer of enriched 14CO2 from the atmosphere reducing the reservoir effect (resulting in negative ∆R values) by 100 to 200 years (see also Hogg et al. 1998). ‘Old Wood’ effect As the charcoal used in the archaeological pairs was not identified, it is possible that the reported charcoal ages are too old for the context. An ‘old wood effect’ can arise where firewood comes from wood lying in the environment (including driftwood) or where the older central sections of large trees are burnt (McFadgen 1982; Schiffer 1986). 164 However, in the study area, wood generally decomposes rapidly in exposed humid environments (see Swift et al. 1979: 317). Thus any ‘old wood effect’ is unlikely to be greater than one to two decades, so it cannot account for the apparent difference between ∆R values inside and outside Moreton Bay. Change in marine reservoir effects through time Although only a small number of data points are available, the ∆R values presented here suggest that ∆R approximated current values during at least the last 500 years, with the possibility of lower ∆R values ~800–900 years ago (Figure 2). Several studies have indicated temporal variation in ∆R for the eastern Australian sea board. The Abraham Reef coral record off the central Queensland coast shows shifts in ∆R over the last 350 years of up to 80 years (Druffel and Griffin 1993, 1995, 1999) while the modelling of Franke et al. (2008) suggests minimum shifts of 300 years over longer timescales. These long-term effects are potentially compounded in embayments where changes in residence times and circulation patterns may change profoundly through time in response to geomorphological processes. As an example, marked changes in sedimentation and circulation patterns are documented in a change in the dominant coral species at Peel and Mud Islands from the clean water Acropora species to the mud-resistant Favia species since 3710±250 BP (Flood 1984: 130; Hekel et al. 1979; Jones et al. 1978: 13) (see Figure 1). Conclusion We recommend a ∆R value of 9±19 for open waters in southeast Queensland, based on dating of known-age shell samples from Stradbroke Island. Determination of ∆R values inside Moreton Bay from archaeological shell/charcoal pairs is complicated by spatial and temporal variation in circulation and sedimentation patterns and terrestrial inputs. As a first approximation, ∆R values inside and outside Moreton Bay can be considered as similar for the recent past, although there are indications that marine reservoir conditions were not constant in Moreton Bay in the past and are strongly related to changing hydrological conditions. Further studies of paired shell/charcoal samples from a range of contexts and time periods will clarify patterns identified here. Acknowledgements Ian Loch (Australian Museum) provided the live-collected specimens for this study. The Australian Institute of Aboriginal and Torres Strait Islander Studies funded excavation and radiocarbon dating of the Lazaret Midden. Paula Reimer (Queen’s University of Belfast) patiently provided advice and encouragement. We thank the University of Waikato’s Radiocarbon Dating Laboratory and International Global Change Institute for hosting Ulm during the writing of this paper. For advice and support, thanks to Alan Hogg, Daniel Rosendahl and Marion Holdaway. For constructive comments on the manuscript we thank Colin Murray-Wallace and Peter White. References Beesley, P.L., G.J.B. Ross and A. Wells (eds) 1998 Mollusca: The Southern Synthesis. Melbourne: CSIRO Publishing. Bronk Ramsey, C. 1995 Radiocarbon calibration and analysis of stratigraphy: The OxCal program. Radiocarbon 37(2):425-430. Bronk Ramsey, C. 2001 Development of the radiocarbon calibration program OxCal. Radiocarbon 43(2A):355-363. Creese, R., S. Hooker, S. De Luca and Y. Wharton 1997 Ecology and environmental impact of Musculsta senhousia (Mollusca: Bivalvia: Mytilidae) in Tamaki Estuary, Auckland, New Zealand. New Zealand Journal of Marine and Freshwater Research 31:225-226. Culleton, B.J., D.J. Kennett, B.L. Ingram, J.M. Erlandson and J.R. Southon 2006 Intrashell radiocarbon variability in marine molluscs. Radiocarbon 48(3):387-400. Dettman, D.L., K.W. Flessa, P.D. Roopnarine, B.R. Schöne and D.H. Goodwin 2004 The use of oxygen isotope variation in shells of estuarine mollusks as a quantitative record of seasonal and annual Colorado River discharge. Geochimica et Cosmochimica Acta 68(6):1253-1263. Druffel, E.R.M. and S. Griffin 1993 Large variations of surface ocean radiocarbon: Evidence of circulation changes in the southwestern Pacific. Journal of Geophysical Research 98:20249-20259. Druffel, E.R.M. and S. Griffin 1995 Regional variability of surface ocean radiocarbon from southern Great Barrier Reef corals. Radiocarbon 37:517-524. Druffel, E.R.M. and S. Griffin 1999 Variability of surface ocean radiocarbon and stable isotopes in the southwestern Pacific. Journal of Geophysical Research 104:23607-23613. Dye, T. 1994 Apparent ages of marine shells: Implications for archaeological dating in Hawai’i. Radiocarbon 36:51-57. Flood, P.G. 1981 Carbon-14 dates from the coastal plains of Deception Bay, southeastern Queensland. Queensland Government Mining Journal 82:19-23. Flood, P.G. 1984 A review of Holocene sea level data, southeastern Queensland. In R.J. Coleman, J. Covacevich and P. Davie (eds), Focus on Stradbroke: New Information on North Stradbroke Island and Surrounding Areas, 1974-1984, pp.127-131. Brisbane: Boolarong Publications. Forman, S.L. and L. Polyak 1997 Radiocarbon content of prebomb marine molluscs and variations in the 14C reservoir age for coastal areas of the Barents and Kara seas, Russia. Geophysical Research Letters 24(8):885-888. Frank, P.W. 1969 Growth rates and longevity of some gastropod molluscs on the coral reef at Heron Island. Oecologia 2:232-250. Franke, J., A. Paul and M. Schulz 2008 Modeling variations of marine reservoir ages during the last 45 000 years. Climate of the Past 4:125-136. Gabric, A.J., J. McEwan and P.R.F. Bell 1998 Water quality and phytoplankton dynamics in Moreton Bay, south-eastern Queensland. I. Field survey and satellite data. Australian Journal of Marine and Freshwater Research 49:215-225. Gillespie, R. 1977 Sydney University natural radiocarbon measurements IV. Radiocarbon 19:101-110. Gillespie, R. and H.A. Polach 1979 The suitability of marine shells for radiocarbon dating of Australian prehistory. In R. Berger and H. Suess (eds), Proceedings of the Ninth International Conference on Radiocarbon Dating, pp.404-421. Los Angeles: University of California Press. Hadwen, W.L. 2006 Ecological Risk Assessment for North Stradbroke Island Groundwater Dependent Ecosystems: Coastal Freshwater/Seawater Interface Ecosystems. Retrieved 5 November 2008 from http://www.dip.qld.gov.au/docs/ library/pdf/water/. Hekel, H., W.T. Ward, M. Jones and D.E. Searle 1979 Geological development of northern Moreton Bay. In A. Bailey and N.C. Stevens (eds), Northern Moreton Bay Symposium: The Proceedings of a Symposium held at the Abel Smith Lecture Theatre, University of Queensland, September 23-24, 1978, pp.7-18. Brisbane: Royal Society of Queensland. Hogg, A.G., T.F.G. Higham and J. Dahm 1998 14C dating of modern marine and estuarine shellfish. Radiocarbon 40:975984. Hughen, K.A., M.G.L. Baillie, E. Bard, J.W. Beck, C.J.H. Bertrand, P.G. Blackwell, C.E. Buck, G.S. Burr, K.B. Cutler, P.E. Damon, R.L. Edwards, R.G. Fairbanks, M. Friedrich, T.P. Guilderson, B. Kromer, G. McCormac, S. Manning, C. Bronk Ramsey, P.J. Reimer, R.W. Reimer, S. Remmele, J.R. Southon, M. Stuiver, S. Talamo, F.W. Taylor, J. van der Plicht and C.E. Weyhenmeyer 2004 MARINE04 marine radiocarbon age calibration, 0-26 cal kyr BP. Radiocarbon 46(3):1059-1086. Jones, M., F. Petchey, R. Green, P. Sheppard and M. Phelan 2007 The marine ∆R for Nenumbo (Solomon Islands): A case study in calculating reservoir offsets from paired sample data. Radiocarbon 49(1):95-102. Jones, M.R. 1992 Moreton Bay and the sand islands. In W. Willmott and N. Stevens (eds), Rocks and Landscapes of Brisbane and Ipswich: Geology and Excursions in the Brisbane, Ipswich, and Pine Rivers Districts, pp.27-31. Brisbane: Geological Society of Australia, Queensland Division. Jones, M., H. Hekel and D.E. Searle 1978 Late Quaternary sedimentation in Moreton Bay. Papers of the Department of Geology University of Queensland 8(2):6-17. Keith, M.L., G.M. Anderson and R. Eichler 1964 Carbon and oxygen isotopic composition of mollusk shells from marine and fresh-water environments. Geochimica et Cosmochimica Acta 28:1757-1786. Kennett, D.J., B.L. Ingram, J.M. Erlandson and P. Walker 1997 Evidence for temporal fluctuations in marine radiocarbon reservoir ages in the Santa Barbara Channel, Southern California. Journal of Archaeological Science 24:1051-1059. King, M. 1976 The Life-History of the Goolwa Cockle, Donax (Plebidonax) deltoides, (Bivalvia: Donacidae), on an Ocean Beach, South Australia. Adelaide: Department of Agriculture and Fisheries. King, M. 1985 A review of the Goolwa cockle. SAFIC 9(5):14. Lamprell, K. and T. Whitehead 1992 Bivalves of Australia. Vol. 1. Bathurst: Crawford House Press. Little, E.A. 1993 Radiocarbon age calibration at archaeological sites of coastal Massachusetts and vicinity. Journal of Archaeological Science 20:457-471. Lovell, E.R. 1975 Evidence for a higher sea level in Moreton Bay, Queensland. Marine Geology 18:M87-M94. Mangerud, J., S. Bondevik, S. Gulliksen, A.K. Hufthammer and T. Høisæter 2006 Marine 14C reservoir ages for 19th century whales and molluscs from the North Atlantic. Quaternary Science Reviews 25:3228-3245. McCormac, F.G., A.G. Hogg, P.G. Blackwell, C.E. Buck, T.F.G. Higham and P.J. Reimer 2004 SHCAL04 southern hemisphere calibration, 0-11.0 cal kyr BP. Radiocarbon 46:1087-1092. McFadgen, B.G. 1982 Dating New Zealand archaeology by radiocarbon. New Zealand Journal of Science 25:379-392. McNiven, I. 2006 Late moves on Donax: Aboriginal marine 165 specialisation in southeast Queensland over the last 6000 years. In S. Ulm and I. Lilley (eds), An Archaeological Life: Papers in Honour of Jay Hall, pp.109-124. Research Report Series 7. Brisbane: Aboriginal and Torres Strait Islander Studies Unit, University of Queensland. Milford, S.N. and J.A. Church 1977 Simplified circulation and mixing models of Moreton Bay, Queensland. Australian Journal of Marine and Freshwater Research 28:23-34. Murray-Jones, S. 1999 Conservation and conservation biology of the pipi, Donax deltoides. Unpublished PhD thesis, School of Biological Sciences, University of Wollongong, Wollongong. Petchey, F. and D.J. Addison 2005 Radiocarbon dating marine shell in Samoa – A review. In D.J. Addison and C. Sand (eds), Recent Advances in the Archaeology of the Fiji/West-Polynesia Region pp.79-86. University of Otago Publications in Prehistoric Anthropology 21, Dunedin. Petchey, F., A. Anderson, A. Hogg and A. Zondervan 2008 The marine reservoir effect in the Southern Ocean: An evaluation of extant and new ∆R values and their application to archaeological chronologies. Journal of the Royal Society of New Zealand 38(4):243-262. Petchey, F., R. Green, M. Jones and M. Phelan 2005 A local marine reservoir correction value (∆R) for Watom Island, Papua New Guinea. New Zealand Journal of Archaeology 26:29-40. Powell, E.N. and H. Cummins 1985 Are molluscan maximum life spans determined by long-term cycles in benthic communities? Oecologia 67:177-182. Prangnell, J. 2002 The archaeology of the Peel Island Lazaret: Part 1: Survey. Queensland Archaeological Research 13:31-38. Reimer, P.J., T.A. Brown and R.W. Reimer 2004 Discussion: Reporting and calibration of post-bomb 14C data. Radiocarbon 46(3):1299-1304. Reimer, P.J., F.G. McCormac, J. Moore, F. McCormick and E.V. Murray 2002 Marine radiocarbon reservoir corrections for the mid- to late Holocene in the eastern subpolar North Atlantic. The Holocene 12(2):129-135. Reimer, P.J. and R.W. Reimer 2008 Marine Reservoir Correction Database. Retrieved from http://calib.org/marine. Ross, A. 2001 The Aboriginal Moreton Bay fishery: Using archaeological evidence to reply to Walters. Australian Aboriginal Studies 2:63-65. Ross, A. and S. Coghill 2000 Conducting a community-based archaeological project: An archaeologist’s and a Koenpul man’s perspective. Australian Aboriginal Studies 1&2:76-83. Ross, A. and R. Duffy 2000 Fine mesh screening of midden material and the recovery of fish bone: The development of flotation and deflocculation techniques for an efficient and effective procedure. Geoarchaeology 15(1):21-41. Schiffer, M.B. 1986 Radiocarbon dating and the ‘old wood’ problem: The case of the Hohokam chronology. Journal of Archaeological Science 13:13-30. Southon, J., M. Kashgarian, M. Fontugne, B. Metivier and W.W-S. Yim 2002 Marine reservoir corrections for the Indian Ocean and Southeast Asia. Radiocarbon 44(1):167-180. Spiker E.G. 1980 The behavior of 14C and 13C in estuarine water: Effects of in situ CO2 production and atmospheric exchange. Radiocarbon 22(3):647-634. Stuiver, M. and T.F. Braziunas 1993 Modeling atmospheric 14C influences and 14C ages of marine samples to 10,000 BC. Radiocarbon 35(1):137-189. Stuiver, M., G.W. Pearson and T. Braziunas 1986 Radiocarbon age calibration of marine samples back to 9000 cal yr BP. Radiocarbon 28(2B):980-1021. Stuiver, M. and H.A. Polach 1977 Discussion: Reporting 14C data. Radiocarbon 19:355-363. Swift, M.J., O.W. Heal and J.M. Anderson 1979 Decomposition in Terrestrial Ecosystems. Oxford: Blackwell. 166 Telford, R.J., E. Heegaard and H.J.B. Birks 2004 The intercept is a poor estimate of a calibrated radiocarbon age. The Holocene 14(2):296-298. Ulm, S. 2002 Marine and estuarine reservoir effects in central Queensland, Australia: Determination of ∆R values. Geoarchaeology 17(4):319-348. Ulm, S. 2006 Australian marine reservoir effects: A guide to Australian ∆R values. Australian Archaeology 63:57-60. Ulm, S. and J. Hall 1996 Radiocarbon and cultural chronologies in southeast Queensland prehistory. In S. Ulm, I. Lilley and A. Ross (eds), Australian Archaeology ’95: Proceedings of the 1995 Australian Archaeological Association Annual Conference, pp.45-62. Tempus 6. St Lucia: Anthropology Museum, Department of Anthropology and Sociology, University of Queensland. Walker, D.R. 1983 Kesteven, Hereward Leighton (1881–1964). Australian Dictionary of Biography, pp.579-580. Vol. 9. Melbourne: Melbourne University Press. Ward, W.T., A.W. Stephens and N. McIntyre 1977 Brisbane’s north coast and Fraser Island from the air. In R.W. Day (ed.), 1977 Field Conference, Lady Elliott Island-Fraser Island-GayndahBiggenden, pp.14-30. Brisbane: Geological Society of Australia, Queensland Branch. ––––––––––––––––––––– Jomon sherds from Aomori, Japan, not Mele, Efate WILLIAM R. DICKINSON and MARY ELIZABETH SHUTLER Keywords: Jomon, Mele Plain, paleoshorelines Abstract The presence of Japanese Jomon sherds from Aomori in an artefact collection from Vanuatu has been attributed alternately to Jomon voyaging or to adventitious mingling of artefacts of different proveniences. The paleoshoreline history of Efate indicates that the site where the Jomon sherds were purportedly collected was submerged during Jomon time, making introduction of the sherds into Vanuatu by Jomon voyagers implausible. The anomalous sherds were probably taken directly from Japan to Paris, and inadvertently introduced there into the Vanuatu collection. In a previous paper (Dickinson et al.1999), we showed from petrographic and microprobe evidence that cord-marked potsherds reportedly discovered as Vanuatu surface artefacts WRD: Department of Geosciences, University of Arizona, PO Box 210077, University of Arizona, Tucson AZ 85721, USA; email: wrdickin@dakotacom.net; MES: College of Letters and Sciences, National University, 11255 N. Torrey Pines Rd., La Jolla CA 92037, USA