CARBON-14 DATE LIST FOR NEWFOUNDLAND AND LABRADOR

DAVID M. TAYLOR AND MARTIN J. BATTERSON

OPEN FILE Nfld 2190, Version 2

NOVEMBER 2001 ST. JOHN'S, NEWFOUNDLAND

INTRODUCTION

The Carbon-14 geochronology date list of Newfoundland and Labrador provides a complete catalogue of carbon-14 age dates for the province. This compilation can be used by geoscientists for a variety of geological purposes, including studies in relative sea level fluctuations, reconstruction of ice margins, and as a guide for future age-dating work. Readers are encouraged to examine this document for accuracy with regard to dates they are familiar with, and to submit to the authors any other dates for inclusion. To date, 1339 dates are included. This compilation will be updated on a yearly basis as more dates become available.

The data is accessible using web-mapping software. At present this does not work with all platforms and browsers- Macintosh users may experience difficulty. Only Newfoundland dates are currently mapped. The information can be found here. Follow the link to Geoscience Resources of Newfoundland. If your operating system and browser are compatible, this will load the mapping software. By clicking on "surficial geology" in the lower panel, the radiocarbon dates will appear as dots overlain on surficial geology mapping. Full data for each site can be viewed by clicking on the dots using the appropriate tool.

In addition the data is available as an Excel file or as a CSV file (click on these links and hold down the mouse until you see the option "download link"). The complete data listing in html format is also available, although this is a large table and may take some time to render on some browsers.

Acknowledgements

Special thanks to Dr. Richard E. Morlan, Curator of Palaeoenvironmental Studies at the Canadian Museum of Civilization for permission to include many of the archaeological dates contained within this listing.

Explanation of data fields

Reference Number (1:250, 1:50, #)

A reference number has been assigned to every site location on the map, which comprises of 3 parts. The first is the 1:250,000 map sheet on which the age-date occurs (eg., 2M). The second part is the 1:50,000 map number (eg., 12). The third part is the reference number assigned to each sample. These numbers follow sequentially, beginning at 1 (eg., 2M-12-1). In cases where there is more than one sample at a site each sample shares a common reference number, although they maintain a discrete laboratory number.

Laboratory Number (Lab #)

This represents the number assigned to the sample by the laboratory at which it was dated e.g., GSC-4211. A guide to abbreviations follows:

Date and Associated Error (Date, Pos, Neg)

The sample date is in years before present (BP). The age range of these dates is from modern to greater than 40,000 BP with most occurring between 1,000 and 14,000 BP. The limit of carbon-14 dating is currently about 60,000 years; the use of linear accelerators possibly extend this limit back to about 100,000 years. All dates have an associated error factor which results from the random nature of radioactive decay. The date is therefore given as a time interval (Pos and Neg) within which the true age will lie, with a certain probability. Generally, the error refers to one standard deviation i.e., there is a 68% probability that the true age lies within the time interval given. However, dates from the GSC are reported within 2 standard deviations. Furthermore, GSC shell dates are normalised to d13C=0% PDB, compared to d13C=-25% PDB for other laboratories. This means that GSC dates are about 410 years younger than would be reported from the same sample by another laboratory. For comparative purposes it is recommended that 410 years be added to GSC ages and the error converted to 1 standard deviation (Miller et al., 1988).

Locality

Locality refers to the community, lake or pond closest to where the sample was taken.

Location

The location of the sample site is given by latitude and longitude, to the closest minute.

Elevation (Elev.)

This generally refers to metres above or below sea level at which the sample was taken. For lake sediment samples (e.g., gyttja) lake surface elevation is given. For dates below sea level depth is indicated by a minus sign.

Collector (Coll.)

This is the initials of the collector of the sample. Refer to Appendix A for names (where known).

Reference

This column represents the source from which the sample information was obtained. Most dates are from the Geological Survey of Canada (GSC) laboratory, and are listed in the radiocarbon date list published yearly by the GSC. However, if the dates are used in a publication, the source is listed in the reference column. Refer to Appendix B for complete citations.

Material

Seven different types of materials have been dated; wood, shells, peat, gyttja (total organics), whale bone, calcite crystals and charcoal. The reliability of ages varies between the types of materials measured, depending on the amount of carbon present with charcoal and wood being the most reliable. Other material may be susceptible to contamination by older or younger carbon, commonly through the action of groundwater. This is especially true for total organic matter samples.

Comments

These are general comments with reference to the date of the sampled material. In most cases these are summarized from comments by the collector.