Radiocarbon dating results from the Beakers and Bodies Project (original) (raw)

The radiocarbon dating programmes of The National Museums of Scotland

Antiquity, 2002

Since 1991, the Archaeology Department of the National Museums of Scotland (NMS) has been undertaking programmes of AMS radiocarbon dating of organic items in its collections, particularly wetland finds. This work was initially stimulated by the success of Caroline Earwood’s research on dating bog butter containers and other wooden vessels from the National collections (Earwood 1990; 1993a; 1993b; 1997), which demonstrated among other things that the practice of bog butter deposition in Scotland extended at least as far back as the early centuries AD.

Radiocarbon Results for the British Beakers

Radiocarbon, 1992

The beginning of the Bronze Age in the British Isles has traditionally been marked by the appearance, in the archaeological record, of Beaker assemblages, mainly characterized by the Beaker pottery form itself. Ceramic typologies based on this style, which is undoubtedly continental in origin, have been used both for relative dating and as evidence of the social and economic developments of the period. Systematic radiocarbon dating has been attempted for the continental European Beaker material (Lanting, Mook & van der Waals 1973), but no such program has been carried out on British material. An examination of the existing radiocarbon results for the British Beakers showed many to be flawed in some way, particularly in the use of materials, such as mature wood, where there is no a priori reason for assuming a direct relationship between sample death and context. An attempt has been made at the British Museum to test the validity of archaeologically derived chronologies for the Beake...

British Museum Natural Radiocarbon Measurements VIII

Radiocarbon: An International Journal of Cosmogenic Isotope Research, 1976

The following list consists entirely of dates for archaeologic samples from the British Isles measured since about mid-1970 up to June 1974*. The dates were obtained by liquid scintillation counting of benzene using a Model 3315 Packard Tricarb Liquid Scintillation Spectrometer. In general, procedures are as described in the previous date list (R, 1971, v 13, p 157; see also Burleigh, 1972). However, data processing was improved by means of a real-time link with a Hewlett Packard 2100A computer having 32K of core, which accepts readings from the counter at the end of each individual counting period. The computer monitors the accumulated sample counts and reports when the statistical error terms of these have reached previously chosen limits; final dates are then obtained on supplying the appropriate benzene sample weights and isotopic fractionation values. The system maintains a permanent record of all the data obtained from measurement of samples and reference standards and gives warning of any serious changes in counter performance. A full description of the capabilities of this system is given elsewhere (Hall and Hewson, in press). Finally, improvements were made to the bomb used for initial combustion of sample materials (Burleigh, 1974) and a new, stainless-steel, lithium reaction furnace (similar to that described by Polach and Stipp, 1967) was recently installed. Raw sample materials are systematically pretreated with dilute acid and alkali; but only collagen is used for antler and bone. The dates, relative to AD 1950, are based on the Libby half-life of 5570 years, are corrected for isotopic fractionation (relative to the PDB standard), and are expressed in radiocarbon years uncorrected for natural 14C variations. NBS oxalic acid is used as the modern reference standard. Descriptions, comments, and references to publications are based on information supplied by the persons who submitted the samples. ACKNOWLEDGMENTS We gratefully acknowledge the continued guidance and helpful criticism and advice of H Barker. SAMPLE DESCRIPTIONS ARCHAEOLOGIC SAMPLES A. British Isles 5730 ± 150 BM-91. High Rocks, Kent 3780 BC Charcoal from Layer 2 (Period III) of Site F at High Rocks, Tunbridge Wells, Kent, England (51° 07' N, 0° 14' E, Nail Grid Ref TQ * Dates obtained over the same period for samples from other geographic regions form the next list, British Museum IX.

British Museum Natural Radiocarbon Measurements IX

Radiocarbon, 1977

The following list consists of dates for archaeologic samples from countries other than the British Isles measured with a few exceptions over the period of mid-1970 to June 1974.' The dates were obtained by liquid scintillation counting of benzene using a Model 3315 Packard Tricarb Liquid Scintillation Spectrometer. The laboratory procedures used were those outlined in the previous date list (R, 1976, v 18, p 16). As before, the dates, relative to AD 1950, are based on the Libby half-life for '4C of 5570 years, are corrected for isotopic fractionation (relative to the PDB standard) and are expressed in radiocarbon years uncorrected for natural 14C variations. NBS oxalic acid is used as the modern reference standard. Descriptions, comments, and references to publications are based on information supplied by the persons who submitted the samples. ACKNOWLEDGMENTS We wish to thank H Barker for helpful criticism and advice. SAMPLE DESCRIPTIONS ARCHAEOLOGIC SAMPLES 559 ± 40 BM-760. Lake Varna boat, Bulgaria AD 1391 Wood (Quercus f rainetto Ten) from structure of boat taken from L Varna, Stalin, Black Sea coast, Bulgaria (43° 20' N, 27° 75' E). Coll 1970 and subm by A Michailov, Nail Inst Cult Properties, Sofia, Bulgaria. Comment: when 1st recovered boat considered prehistoric; actual date is clearly much more recent. 12,984 ± 76 BM-728. Mylodon Cave, Chile 11,034 BC Collagen from femur of mylodon (giant sloth, Grypotherium listai) from Cueva del Milodon Grande, Puerto Consuelo, Ultima Esperanza, Chile (51° 36' S, 72° 36' W). Coll ca 1900 from cave floor deposits beneath fallen roof debris (British Mus [Nat Hist] ref M8748; purchased from G A Milward, 1904). Subm by A J Sutcliffe, British Mus (Nat Hist) to * Dates obtained over the same period for samples from the British Isles formed the previous list, British Museum VIII. troversy because of surviving flesh and hair. Comment: date confirms Pleistocene age of remains and agrees with C-484: 10,832 ± 400, for giant sloth droppings from same site (Libby, 1952, p 94). Carrizal series, Colombia Charcoal from protohist Carrizal phase occupation levels overlying Antigua levels at Carrizal, Municipio Barichava, Santander, Colombia (6° 40' N, 73° 14' W). Coil 1970 and subm by W Bray, Inst Archaeol, Univ London. 603 ± 63 BM-802. Carrizal AD 1347 Carrizal stratigraphic trench, Levels 4 and 5, 30 to 50 cm below surface. Dates middle part of Carizal phase occupation. 682 ± 66 BM-803. Carrizal AD 1268 Carrizal stratigraphic trench, Level 7, 60 to 70 cm below surface. Comment: samples should date transition from underlying Antigua phase (see BM-804-806, below) but appear contemporaneous with BM-802 from middle of Carrizal phase. Cueva la Antigua series, Colombia Charcoal from Antigua phase levels at Cueva la Antigua, Municipio of San Gil, Santander, Colombia (6° 35' N, 73° 10' W). Coil 1970 and subm by W Bray. Samples date newly defined Antigua phase pottery styles, earliest so far discovered in northern part of highland Colombia. 1368 ± 103 BM804. Cueva la Antigua AD 582 Trench 1/2, Spit 1 of Antigua phase. Dates transition from Antigua phase to subsequent protohist Carrizal phase.

MARINE RADIOCARBON RESERVOIR AGES IN SCOTTISH COASTAL AND FJORDIC WATERS

2006

High freshwater inputs into Scottish sea lochs (fjords) combined with the restricted exchange between sea loch basin water and coastal Atlantic water masses are likely to result in reduced regional marine radiocarbon reservoir ages (R[t]) in these environments. To test this hypothesis, historical, museum-archived shells, collected live on known dates prior to AD 1950 from coastal locations in NW Scotland, were 14 C dated to provide a means of determining R(t) and hence the regional deviation (∆R) from the modeled global surface ocean reservoir age (R). The sea loch data, when combined with 14 C dates from the Scottish west coast (Harkness 1983), yield a regional ∆R value of -26 ± 14 yr. The ∆R of sea loch (fjordic) and coastal waters of NW Scotland are statistically different (at a confidence level >95%) from the ∆R value of 17 ± 14 yr reported for UK coastal waters data after Harkness 1983) and are in good agreement with the coastal ∆R value of -33 ± 93 yr reported by . Therefore, it is recommended that a regional ∆R correction of -26 ± 14 yr should be applied to modern (i.e. pre-bomb but not prehistoric) marine 14 C dates from the NW coast of Scotland.

British Museum Natural Radiocarbon Measurements VI

Radiocarbon, 1969

Dates listed below are based on measurements made up to May 1968, and cover a period during which the technique of gas proportional counting using CO2 was gradually replaced by liquid scintillation counting using benzene. The gas counting measurements were carried out by the method and techniques previously described (Barker and Mackey, 1968) the only modifications being the replacement of some old electronic units by more stable solid-state equipment; proportional counting results are indicated in the text by (P) at the end of the relevant sample descriptions. Liquid scintillation counting, which is now the preferred method in this laboratory, is carried out using a Packard Tri-Carb liquid scintillation spectrometer model 3315/AES fitted with selected low-noise quartz-faced photomultipliers. Normally 3 ml of benzene is prepared from each sample. This is dissolved in 12 ml of scintillation grade toluene containing 5 gm/liter of scintillator (PPO) and the solution is measured in a standard low-potassium glass vial at a temperature of 0°C. Photomultiplier E.H.T., amplifier, and channel width settings are optimized for C14, and measurements are carried out at ca. 65% efficiency of detection for C14 to eliminate interference from any tritium which may be present in the benzene. Under these circumstances the background is approx. 8.6 cpm and the modern (95% A0X) is approx. 24.0 cpm. Samples are counted in groups of 3 to 5 together with background and modern reference samples and are measured for at least one week, the instrument being set to cycle at 100 min intervals. In this period, the counts accumulated are such that the background is always measured to a statistical accuracy of better than 1% and most other samples to a higher accuracy than this. Background and modern counts used in the calculation of each result are only those relevant to the period of measurement of that particular sample. Statistical analysis of groups of replicate measurements made under these conditions over a very long period of time has demonstrated the excellent long-term stability of the equipment and indicates that the technique is quite capable of achieving results of very high statistical accuracy when required. SAMPLE DESCRIPTIONS ARCHAEOLOGIC SAMPLES A. Crete Knossos series Five samples from Neolithic settlement of Knossos, Crete (35° 31' N Lat, 25 ° 20' E Long), from sounding below central court of Minoan Palace (Evans, 1964a,b). Coll. 1960 and subm. by J. D. Evans, Inst. of Archaeol., Univ. of London, for comparison with unexpectedly early dates previously obtained for Knossos Neolithic, BM-124, 8050 ± 180 and BM-126, 7000 + 180 (Radiocarbon, 1963, v. 5, p. 104). 7570 ± 150 BM-272. Knossos 2 5620 B.C. Sample 2, ref. Area AC, Level 24. Charcoal from Occupation layer assoc. with 1st brick houses and immediately overlying earliest camp occupation above bedrock (Stratum IX, Evans, 1964b). Expected age early 6th millennium B.C. based on BM-124 and BM-126. (P) 6210 ± 150 BM-273. Knossos 3 4260 B.C. Sample 3, ref. Area AC, Level 17. Charcoal from habitation deposit in Stratum VI (Evans, 1964b). Expected age late 6th millennium B.C. based on BM-124 and BM-126. (P) 6140 ± 150 BM-274. Knossos 4 4190 B.C. Sample 4, ref. Area A, Level 15. Charcoal from habitation level in Stratum V (Evans, 1964b). Expected age end of 6th millennium B.C. based on BM-124 and BM-126. (P)

Radiocarbon Dating Tephra Layers in Britain and Iceland

Radiocarbon, 1995

Layers of volcanic ash, or tephra form widespread chronostratigraphic marker horizons which are important because of their distinctive characteristics and rapid deposition over large areas. Absolute dating of prehistoric layers effectively depends upon 14C analysis. We focus here on Icelandic tephra layers at both proximal and distal sites and consider three strategies to obtain age estimates: 1) the conventional dating of individual profiles; 2) high-precision multisample techniques or “wiggle-matching” using stratigraphic sequences of peat; and 3) a combination of routine analyses from multiple sites. The first approach is illustrated by the dating of a peat profile in Scotland containing tephra from the ad 1510 eruption of Hekla. This produced a 14C age compatible with ad 1510, independently derived by geochemical correlation with historically dated Icelandic deposits. In addition, the ca. 2100 bp date for the Glen Garry tephra in Scotland, determined by a series of dates on a pe...

Radiocarbon dating and marine reservoir correction of Viking Age Christian burials from Orkney

Dating the earliest Christian burials in Viking Age Orkney is complicated by marine reservoir effects which can make radiocarbon assays on bone from fish-eaters appear inappropriately old. This paper provides corrected dates for burials from two chapels which m a y pre-date the traditional conversion of Scandinavian Scotland and highlights unresolved aspects of calibrating samples of mixed terrestrial and marine origin.