Árný E. Sveinbjörnsdóttir

Successful AMS 14C Dating of Non-Hydraulic Lime Mortars from the Medieval Churches of the Åland Islands, Finland

Fifteen years of research on accelerator mass spectrometry (AMS) radiocarbon dating of non-hydraulic mortar has now led to the establishment of a chronology for the medieval stone churches of the Aland Islands (Finland), where no contemporary written records could shed light on the first building phases. In contrast to other material for dating, well-pre- served mortar is abundantly available from every building stage. We have gathered experience from AMS dating of 150 Aland mortar samples. Approximately half of them have age control from dendrochronology or from 14C analysis of wooden fragments in direct contact with the mortar. Of the samples with age control, 95% of the results agree with the age of the wood. The age control from dendrochronology, petrologic microscopy, chemical testing of the mortars, and mathematical modeling of their behavior during dissolution in acid have helped us to define criteria of reliability to interpret the 14C results when mortar dating is the only possibility to constrain the buildings in time. With these criteria, 80% of all samples reached conclusive results, and we have thus far been able to establish the chro- nology of 12 out of the 14 churches and chapels, while 2 still require complementary analyses.

Radiocarbon Anomalies Observed for Plants Growing in Icelandic Geothermal Waters

Distribution profiles of radiocarbon in dissolved inorganic carbonate have been measured along two transects in the southern Pacific, east of New Zealand. Use of accelerator mass spectrometry, with its small-sample-size capability, made it possible to sample near-surface waters with a depth resolution of a few tens of meters. Sampling of deeper water was guided by salinity and temperature data transmitted by a conductivity-temperature-depth probe. The measurements, taken over the Chatham Rise, show highly structured profiles that can be correlated with known circulation patterns in this region.

Dietary Reconstruction and Reservoir Correction of 14C Dates on Bones from Pagan and Early Christian Graves in Iceland

In this study, ?13C and ?15N of bone samples from 83 skeletons (79 humans, 2 horses, and 2 dogs) excavated from pagan and early Christian graves from 21 localities in Iceland are used to reconstruct diet of the early settlers in Iceland and possible differences in diet depending on the distance between the excavation site and the seashore. We have radiocarbon dated 47 of these skeletons and used the carbon isotopic composition (?13C) to estimate and correct for the marine reservoir effect (the 14C difference between terrestrial and mixed marine organisms). The reservoir-corrected ages lie in the range of AD 780?1270 (68.2% probability). Reservoir age corrections were checked by comparing 14C dates of a horse (terrestrial diet), a dog (highly marine diet), and a human (mixed diet) from the same burial. The range in measured marine protein percentage in individual diet is from about 10% up to 55%, mostly depending on the geographical position (distance from the sea) of the excavation site. We had access to the skeleton (AAR-5908) of the Sk?lholt bishop P?ll J?nsson whose remains are enshrined at the Episcopal residence in Sk?lholt, southern Iceland. According to written sources, the bishop died in AD 1211. Using our dietary reconstruction, his bones were about 17% marine, which is within the range of human skeletons from the same area, and the reservoir-corrected calibrated 14C age of the skeleton is in accord with the historical date.

Norse Greenland Dietary Economy ca. AD 980-ca. AD 1450: Introduction

Abstract An initial study of the 13 C values for human bone collagen of 27 Norse Greenlanders in the late 1990s suggested a change in the Norse diet from predominantly terrestrial to predominantly marine food. This shift may well indicate a change in diet; the question left open by the limited initial isotope study was, however, whether the change in diet was a reflection of altered subsistence strategies or altered farming practices. Furthermore, the first study did not convincingly answer the question of whether the dietary change occurred gradually over time or within the space of a few years—and, if the latter case, when? Neither did it answer questions concerning dietary differences between the two Norse settlements, between individual farms and between the sexes, or the nature of the marine food that was consumed. Distinguishing locally born people from foreigners is yet another matter for investigation in order to leave out of account persons that grew up outside of Greenland. This new study includes 437 samples: 183 from humans—118 Norse and 65 Inuit—and 254 from animals. The samples are from 19 Norse sites (farms): 13 from the Eastern Settlement and 6 are from the Western Settlement. For comparison, we have also included samples from both humans and animals from 22 Inuit sites. This paper sets the scene for the new study and the following papers in this Special Volume. Former studies in Norse diet and Norse resource utilization are recapitulated, and all the Norse sites represented in the study are presented, as are all the samples included in the study. Chronology is a recurrent problem in Norse archaeology, and our focus, in particular, is on the attempt to date the samples included in the study that have not been radiocarbon dated.

An Isotopic Analysis of the Diet of the Greenland Norse

Abstract Our understanding of the Norse dietary adaptations to their Greenlandic home comes primarily from sparse historical records, from what is known of the Norse dietary economy in other North Atlantic lands, and from zooarchaeological examinations of the animal bones found in the various excavations of Norse Greenlandic sites which have taken place over the past century. To obtain more detailed information on the diets of the Norse settlers in Greenland, measures of the stable carbon (&dgr;13C) and nitrogen (&dgr;15N) values of human bone collagen have been made for 80 individuals from an existing collection of Norse skeletal material. The material is from five churchyards in the Norse Eastern Settlement and two churchyards in the Western Settlement. These data are interpreted with the aid of similar data obtained for the wild fauna of Greenland, for the Norse domestic animals and for a number of Thule Culture individuals of about the same time period. It is clear that application of the isotopic dietary method to Greenland is complex, but even so, it can provide very useful information. It is also clear that the isotopic method provides reliable information on Greenlandic diet even at the level of the individual. For the two Norse settlements taken as a whole, the basic dietary economy was based about as much on hunting as it was on their domestic animals. We see no evidence for real differences between the diets of men and women or between individuals of different ages. The large individual differences are then likely connected to status or circumstance, but not to sex or age.