Luminescence Dating in Archaeology: from Origins to Optical
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Radiation Measurements Vol. 27, No. 5/6, pp. 819±892, 1997 # 1998 Elsevier Science Ltd. All rights reserved Printed in Great Britain PII: S1350-4487(97)00221-7 1350-4487/98 $19.00 + 0.00 LUMINESCENCE DATING IN ARCHAEOLOGY: FROM ORIGINS TO OPTICAL RICHARD G. ROBERTS School of Earth Sciences, La Trobe University, Melbourne, Victoria 3083, Australia AbstractÐLuminescence dating has a proud history of association with archaeology, beginning almost half a century ago. The subsequent decades of research have seen a range of archaeometric applications of luminescence dating: from ®red pottery and burnt ¯ints to sediments incorporated into occupation deposits and earthen constructions. Important contributions have been made to topics as diverse as modern human origins, continental colonisations and the dating of prehistoric rock art. This paper pro- vides an overview of these applications, with a particular focus on recent ®ndings such as those from Tabun Cave in Israel, Diring Yuriakh in Siberia, and Jinmium in Australia. # 1998 Elsevier Science Ltd. All rights reserved 1. INTRODUCTION the key papers published over the past few decades. While some of the more recent and controversial contributions are discussed at length, mention is also made of the less publicised luminescence stu- That they were repositories of the dead, has been obvious to all: but on what particular occasion constructed, was matter dies that have laid many of the technical foun- of doubt. (Thomas Jeerson, 1787, Query XI ``Aborigines'') dations for the dating method. Attention is drawn also to studies that have tackled a long-standing archaeological problem using a novel luminescence More than two centuries have elapsed since technique, or that have reported a technical devel- Thomas Jeerson contemplated the antiquity of opment with implications beyond the speci®c prehistoric burial mounds in North America and archaeological application. Some contributions of became ``the ®rst scienti®c digger'' in the history of luminescence dating to archaeologically-relevant archaeology (Wheeler, 1956, p. 58) when he dug a issues (e.g. environmental change, faunal extinc- trench through a mound in Virginia and examined tions) are discussed brie¯y, as are a variety of po- its internal strata (Jeerson, 1787). Such anthropo- tential avenues for pro®table future archaeometric genic structures have only recently been investigated research. using luminescence methods (Feathers, 1997a,b; The paper is organised into sections based loosely Saunders et al., 1997), whose pedigree in archaeolo- on archaeological ``themes'' or periods, rather than gical research extends back to the pioneering work on luminescence dating methods (TL or OSL) or of Daniels et al. (1953). This team recognised the procedures (palaeodose or dose rate determi- potential for dating heated artefacts using thermolu- nations). I have attempted to make the technical minescence (TL), an archaeometric tradition sub- discussion in each section as self-contained as poss- sequently continued by Ugumori and Ikeya (1980) ible, but the details of speci®c luminescence dating in the ®rst application of optically stimulated lumi- techniques are given elsewhere in this special nescence (OSL) to archaeologically-relevant ma- volume (Prescott and Robertson, 1997; Wintle, terial (CaCO3). Following these novel insights, TL 1997) and in more than 20 reviews, several written and OSL techniques have been developed and speci®cally for archaeologists, published over the tested extensively on a vast array of archaeological past two decades (Aitken, 1977, 1985, 1989, 1990, materials and across a wide range of archaeological 1994, 1998; Berger, 1988, 1995; Duller, 1996; issues; from human origins to human constructions, Feathers, 1997a; Fleming, 1979; Forman, 1989; from rock shelters to rock art. Huntley and Lian, 1997; Lamothe et al., 1984; The aim of this paper is to present a broad over- Mejdahl, 1986; Mejdahl and Wintle, 1984; Roberts view of these archaeometric applications of lumines- and Jones, 1994; Seeley, 1975; Singhvi and Mejdahl, cence dating, from its origins in pottery dating to 1985; Singhvi and Wagner, 1986; Wagner et al., the application of optical dating to archaeological 1983; Wintle, 1980, 1987, 1993; Wintle and sediments. The huge volume of literature on the Huntley, 1982). subject precludes a truly comprehensive review, but A variety of archaeological themes are pursued in I have attempted to illustrate the diversity of the this paper. The choice is idiosyncratic and biased archaeological applications by reference to many of towards those in which luminescence dating has 819 820 R. G. ROBERTS thrown the greatest light on a major problem or body of the pot, thereby zeroing the luminescence period in archaeology. The theme of Australian ``clock'' which, for dating purposes, is based on colonisation is given particular prominence, not electron traps in the temperature range 300±4508C only because of my familiarity with the subject but (e.g. the 3758C peak in quartz). At the outset, pot- also because TL and optical dating of archaeologi- tery of ``known'' antiquity (established on the basis cal sediments in Australia provides a striking coun- of pottery style, site stratigraphy, and uncalibrated terpoint to TL dating of pottery and burnt ¯int, radiocarbon (14C) ages) was tested to verify the age which has dominated luminescence studies in determinations made using the infant TL methods Europe and the Middle East. I have attempted to (Fig. 1). Pot sherds up to 8000 years old from the make this overview appealing to graduate students Middle East (Iran, Turkey and the Levant), Britain and professional practitioners in both archaeology (particularly from the Roman period), Italy, and Quaternary geochronology, but I apologise to Denmark, Peru and Thailand were tried initially those whose work has been overlooked, misrepre- (Aitken et al., 1963, 1964, 1968; Mazess and sented, or cited in an improper context. Zimmerman, 1966; Mejdahl, 1969; Ralph and Han, 1966; Ralph and Han, 1969; Zimmerman and Huxtable, 1969). The bleaching of TL signals by 2. MODERN TO MESOLITHIC sunlight was explicitly reported for both CaCO3 and sediment in the ®rst of these trials (Aitken et 2.1. Pots and potentates al., 1963), but Soviet scientists are generally credited Artefacts provide crucial evidence of human ac- with being the ®rst to recognise the potential to tivity, and the abundant remains of ancient pots date solar-reset sediments using TL (Morozov, and ceramic vessels are among the most valuable to 1968; Shelkoplyas, 1971; Shelkoplyas and Morozov, archaeologists. Luminescence dating made its ear- 1965). Not until the 1980s was optical dating of cal- liest forays into archaeology through the appli- cite and sediment attempted (Huntley et al., 1985; cation of TL methods to heated pottery and Ugumori and Ikeya, 1980). ceramics from ancient Kingdoms, Empires, TL dating continued to develop during the 1960s Dynasties and civilisations. Firing of pottery (to and 1970s, largely through the eorts of the above 5008C) evicts the electrons trapped over geo- research team led by M. Aitken at Oxford logical time in the minerals which make up the University, and the technique became increasingly 150 100 50 SPECIFIC GLOW (Arbitrary Units) 1000 1000 2000 3000 4000 5000 6000 A.D. B.C. ARCHAEOLOGICAL AGE Fig. 1. An early attempt to compare the TL from 18 heated pot sherds with their known archaeological ages. The ``speci®c glow'' is de®ned as the natural TL (in the 350±4508C temperature region of the glow curve) divided by the product of the dose-regenerated TL and the sherd radioactivity. The speci®c glow is approximately proportional to age (after Aitken et al., 1963). LUMINESCENCE DATING IN ARCHAEOLOGY 821 recognised as an independent method for authenti- tary deposits (Wintle, 1978; Wintle and Huntley, cating the age of ®red pottery, ceramics and the 1979). The latter techniques were ®rst applied in clay cores of bronze casts (e.g. Zimmerman et al., archaeological contexts by Debenham (1983) and 1974). Progress was not made without the oc- Readhead (1982), both workers independently casional stumble, such as the notorious ``Glozel'' devising a combined additive/regenerative TL controversy which threw the validity of TL dating method that is now generally called the ``Australian into some doubt (see Aitken, 1985 for an historical slide'' method (Prescott et al., 1993). An earlier ver- account). But the re®nement of quartz inclusion sion of this approach had been proposed for lava- (Fleming, 1970) and ®ne-grain (Zimmerman, 1971) baked quartz pebbles by Valladas and Gillot (1978), TL techniques, and the development of feldspar in- and extended to burnt ¯ints by Valladas (1978). clusion (Mejdahl, 1972), pre-dose (Fleming, 1973a) The second signi®cant feature of the Zimmerman and zircon (Sutton and Zimmerman, 1976; and Huxtable (1971) paper is the comparison made Zimmerman et al., 1974) dating methods, culmi- between TL and 14C ages for a soil layer deposited nated in a successful series of forgery identi®cations, more than 30,000 years ago, from which animal and including the ``Hacilar'' ceramic wares from Turkey human ®gurines had been recovered. They showed (Aitken et al., 1971), and the supposedly T'ang that uncalibrated 14C ages underestimated TL ages Dynasty ceramics (Fleming, 1973b) and Hui Hsien (corrected for supralinearity) by 04000 years at style pottery (Fleming and Sampson, 1972) from 033,000 calendar years before present. Samples of China; additional