Dating bricks of the last two millennia from Newcastle upon Tyne: a preliminary study I.K. Baili*, N. Holland Luminescence Dating Laboratory, Department of Archaeology, University of Durham, South Road, Durham DH1 3LE, UK Received 30 October 1999; accepted 3 December 1999 Abstract Bricks from a group of four independently dated late medieval buildings in Newcastle upon Tyne have been tested to establish their suitability for luminescence dating as part of a wider study of the dating of post-Roman and medieval brick buildings. The luminescence characteristics of quartz extracted from the bricks were determined using TL (2108C peak) and OSL measurement procedures. Both TL and OSL measurement procedures based on SAR and SARA protocols were applied to determine the palaeodose. The luminescence dates for three sampled locations are in good agreement with the assigned architectural dates; the fourth appears to be older raising doubts concerning the architectural assessment of the sampled phase. 7 2000 Elsevier Science Ltd. All rights reserved. 1. Introduction At present the only methods available for determin- ing the age of much of the brickwork of standing buildings of the late medieval and early modern periods in Britain (i.e. 14th±19th centuries A.D.) are based on either surviving historical records or on typo- logical comparisons. Depending on the region con- cerned, typological dating may at best only enable dating within 50 years and in many cases the uncer- tainty exceeds a century. This paper presents the preliminary results of a study that aims to develop procedures for the routine dating of bricks from standing medieval buildings in Britain. Brick samples were taken from late medieval buildings in Newcastle upon Tyne (see Table 1) where dates have been assigned by architectural historians. A further excavated brick of putatively Roman age from the nearby archaeological site of the medieval Jarrow Monastery was also examined. It was included to test the properties of brick from the same region but man- ufactured under dierent conditions and with substan- tially higher palaeodose. 2. Sample preparation and measurement conditions HF etched quartz grains within the size range 90± 150 mm were extracted from the bricks using standard quartz inclusion separation procedures. A 1 cm thick slice was cut from each brick and the outer 2 mm removed from all faces using a water-cooled diamond saw and abrasive wheel; the slice was mechanically crushed by hand. Part of the crushed material was sieved into three fractions (<90 mm, 90±150 mm and >150 mm) and the remainder ball-milled for use in dose-rate assessment. The 90±150 mm sieved fraction was etched in HF (40%, 45 min) followed by washing in HCl (32%, 45 min). The measurement sample com- prised inclusions of size >90 mm and densities between Radiation Measurements 32 (2000) 615±619 1350-4487/00/$ - see front matter 7 2000 Elsevier Science Ltd. All rights reserved. PII: S1350-4487(99)00286-3 www.elsevier.com/locate/radmeas * Corresponding author. Tel.: +44 (0)191 374 3741. E-mail address: ian.baili@durham.ac.uk (I.K. Baili).