Dating the construction of a Late Prehistoric megalithic monument at Cruz de Cepos, NE Portugal.

The presence of many 'standing stone' monuments within the European Late Prehistoric landscape is considered to be associated with a pivotal human cultural transition from hunting and gathering to agriculture and settlement, currently dated by radiocarbon to the 5th millennium BCE [1]. However, many standing stones were first erected, subsequently collapsed, and then re-erected during the following three millennia [2]. A major difficulty encountered in attempting to apply radiocarbon in previous field investigation to understand these events is identifying samples that are securely related to the construction process. The site of Cruz de Cepos in NW Portugal has been excavated with the aim of learning more of the method of construction of the megalithic monument and, in particular, to explore the potential for application of radiocarbon and luminescence techniques to obtain a reliable chronological framework for its erection. Fortunately, samples suitable for both methods were available and obtained during a programme of excavation of the Cruz de Cepos monument. This paper discusses the luminescence and dosimetry characteristics of quartz extracted from sediment samples taken from locations associated with the socket and surrounding original backfilling deposits, and the OSL single-grain dates produced. The latter are compared with the radiocarbon dates and the prospects for wider application to megalithic monuments of this type is assessed. [ABSTRACT FROM AUTHOR]