Luminescence dating of sediments from two sites near Anuradhapura, Sri Lanka

Cresswell, A.J. , Sanderson, D.C.W. and Simpson, I.A. (2009) Luminescence dating of sediments from two sites near Anuradhapura, Sri Lanka. Technical Report. SUERC, East Kilbride, UK.

Abstract

Previous Optical Stimulated Luminescence (OSL) investigations of irrigation features and archaeological sites in the hinterland around Anuradhapura, Sri Lanka, had observed highly heterogeneous dose distributions and apparent ages older than expected for bunds and similar constructions. These observations are consistent with utilising older sedimentary materials, which did not have their luminescence signals reset during construction. The work reported here consists of OSL measurements from two sites in the Anuradhapura region. The first is a modern bund, sampled to examine the degree of heterogeneity of the dose distributions from a control structure. Two samples were taken from within this bund, one near the top and the other just above the land surface the bund was built upon. These show dose distributions that are highly heterogeneous with apparent ages in excess of 1500 years. The third sample from this site is from the truncated land surface beneath the bund, and gives a luminescence age of 150 ± 40 years with just one much older aliquot. The second site in this work is an abandoned red-earth platform site, covered by an extensive layer of cultural deposits. A sample from the overlying deposits just above the constructed platform gives a luminescence age of 540 ± 70 years, with a homogenous dose distribution. A sample from near the top of the constructed platform gives a heterogeneous dose distribution and apparent ages up to 4000 years. The results support the inferences from earlier sampling, providing clear confirmation that platform sites contain unbleached, re-deposited sediments, with significant residual OSL ages. The OSL results from the underlying land surfaces, and from slowly accumulated abandonment layers, appear to be consistent with external age control where available and thus are to be preferred as targets for OSL dating in such geo-archaeological investigations.

• Item Type: Research Reports or Papers (Technical Report)
• Status: Published
• Glasgow Author(s) Enlighten ID: Sanderson, Professor David and Cresswell, Dr Alan
• Authors: Cresswell, A.J., Sanderson, D.C.W., and Simpson, I.A.
• Subjects: G Geography. Anthropology. Recreation > GB Physical geography; G Geography. Anthropology. Recreation > GE Environmental Sciences
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Publisher: SUERC
• Copyright Holders: Copyright © 2009 Scottish Universities Environmental Research Centre
• Publisher Policy: Reproduced with the permission of the Authors