radiocarbon dating of ancient rock paintings

Radiocarbon Dating of Ancient Rock Paintings

Marvin W. Rowe

Texas A&M University College Station and Qatar

A technique based on cold argon and oxygen plasmaspermits radiocarbon dates to be obtained on paintings thatcontain inorganic pigments. (To listen to a podcast aboutthis feature, please go to the Analytical Chemistry websiteat http://pubs.acs.org/journal/ancham.)

Rock art images are among the most enigmatic and personalartifacts studied in paleoarchaeology. Rock paintings (pictographs)left by ancient prehistoric cultures are found all over theworldsvirtually everywhere there are rocks. One example of apolychrome painting in the lower Pecos River region of southwestTexas (where thousands of other impressive painted images arefound on the limestone shelter walls) is shown in Figure 1. Twofrequently asked questions are, without regard to location, howold is it and what does it mean? This review deals with attemptsto answer the question of age.1

Rock art is an important, irreplaceable part of our heritage.When there is inadequate ethnology for a region, as is most oftenthe case, it can be argued that rock art is the most importantevidence available for discerning the thought processes and theaesthetic, symbolic, and religious ideas of the prehistoric culturesof the peoples who painted them.2 But to incorporate rock artinto mainstream archaeological thought, one must be able toassign it to a specific ancient culture and time span.

Archaeology gained an important technique for dating archaeo-logical artifacts in the 1940s when Willard Libby and his colleaguesdeveloped radiocarbon dating,3,4 a revolutionary method for whichhe was awarded the 1960 Nobel Prize in Chemistry. Thus, whenwe were asked about two decades ago by anthropologist HarryShafer to date a piece of a pictograph that had been picked upfrom the floor of an ancient painted shelter in southwest Texas,we primarily considered radiocarbon dating while trying to devisea means of dating that pictograph.

The principle of radiocarbon dating is deceptively simple.Radioactive 14C, or radiocarbon, is continuously produced inthe earth’s upper atmosphere by interactions of secondarycosmic ray neutrons with the most common atmosphericisotope, 14N. The 14C produced is rapidly oxidized to 14CO2 andquickly distributed throughout the atmosphere, thus becoming

incorporated into the earth’s biological carbon cycle. For thispaper, we assume that most living matter has a very similar14C/12C level. When an organism dies, the contemporary 14C

Figure 1. Polychrome pictograph from shelter 41VV83 in the lowerPecos River region of southwest Texas. Colors are dark red, yellow,and black. The central figure is ∼1/2 m tall and is called the EcstaticShaman or the Electric Jesus. The ages determined for paintings ofthis style are 3000-4000 years.1

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level is no longer fixed into biological tissues, and that whichremains decreases through radioactive decay; the half-life is5730 years. Thus the measured level of 14C in a dead organismcompared with the constant level in living material leads to anestimate of the date of death of the organism. In practice, thereare many refinements, most of which have been worked outin considerable detail over the past six decades. It remains themost accurate and reliable dating technique in archaeology.

Only with the advent of accelerator MS (AMS) for measuringradiocarbon did it become feasible to date pictographs.5-12 AMShas greatly reduced the amount of carbon necessary for determin-ing a radiocarbon date, from several grams in conventional datingto ∼0.05 mg.

The first radiocarbon dates on charcoal pigments from picto-graphs were published in 1987.11,12 Inorganic (mineral) pigmentsare far more frequently used for pictographs than is charcoal, evenfor black pigment. Reds, oranges, yellows, browns, and purplesare iron oxide/hydroxides, and black paintings are often manga-nese oxide/hydroxides.13 Figure 2 is a photograph of a polishedsection of an iron oxide pictograph from southwest Texas. Threelayers are clearly seen. The outside is an accretion layer usuallycomposed of calcite, gypsum, and calcium oxalate. Then comesan underlying red iron oxide/hydroxide layer (the paint pigment),and finally the rock to which paint was applied, in this caselimestone. Sometimes a preexisting accretion layer underlies thepaint.14,15

Rock paintings are among the most difficult archaeologicalartifacts to date. None of the inorganic pigments typically foundin rock art can be radiocarbon dated; those pictographs can bedated only if organic material was added in the preparation of thepaint. If this was not done, creating a chronology will depend ona wider-ranging archaeological investigation of the context inwhich the image was created. If organic material was added,

enough of it must have survived for an AMS measurement froma reasonably small area (∼2 × 2 cm); the amounts of carbonextracted are routinely near the limit of accurate measurementby AMS (60-150 µg carbon). In addition, the rock that waspainted upon must not contain significant indigenous organicmatter itself. These criteria are often, but not always, met.16,17

Other properties of the rock and paint that could be problem-atic must be considered. There must be no exchange in the carbonisotopes after death of the organism, that is, there must be nochange in the 14C/12C except that due to radioactive decay. Ourdates are compared with materials of known age (Figure 3) toensure that this criterion is met.16-20 Extraction of the organiccarbon must not introduce significant mass fractionation, and, asseen in Figure 2, one needs to be able to separate the organicmatter from the paint sample without contamination from lime-stone or calcium oxalate, either of which would nullify a date. Ourmeasurements of δ13C indicate that plasma chemical extractiondoes not introduce significant fractionation of the carbonisotopes.18-20 In addition, the technique was primarily aimed atovercoming the potential contamination from carbonates oroxalates, so there is no need for the harsh strong acid/strongbase treatments normally used to date charcoal and other organicarchaeological artifacts.16-20

RADIOCARBON DATING TECHNIQUESTwo basic means have been used to radiocarbon date rockpaintings. The most common one is based on the analysis oforganic pigments. Charcoal is often the pigment used for produc-ing black rock paintings (MnO2 is also common). Charcoalpaintings were the first to be radiocarbon dated, and theyrepresent a substantial fraction of the dated pictographs,especially for Paleolithic rock paintings.11,12,21-31 In the Euro-pean Paleolithic caves, researchers have concentrated entirely on

Figure 2. A polished cross section of a pictograph with red pigment.Three layers are clearly seen: an overlying calcite/calcium oxalatemineral accretion, the iron ocher pigment, and the underlyinglimestone.

Figure 3. Radiocarbon dates obtained by plasma chemical extractionof widely differing kinds of organic archaeological artifacts comparedwith those from previous work, or destructive AMS dating.

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dating charcoal pigments. The experimental procedure for char-coal pigments is the same as for other archaeological charcoal,that is, alternating acid, base, and acid soaks at 50-70 °C; thus itcan be reliably done. The difference is that samples from rockpaintings are virtually always much smaller than those taken fromother archaeological charcoal.1

Charcoal is a commonly dated archaeological material, but itdates the death of the plant from which it was made, not the timeof an archaeological event of interest, in our case a rock painting.Thus, the charcoal used as pigment could have been much olderthan the painting itself. It is also possible that the wood used tomake the charcoal might have died a long time before it wasburned into charcoal.32 Either of these cases, old charcoal or oldwood, can complicate the analysis, and rarely can these possibili-ties be totally eliminated.

A second possibility in the case of old charcoal is that the woodcould have been burned at an earlier unknown time and theresultant charcoal used much later to execute a painting.33-35

Caution is necessary when interpreting charcoal-derived radio-carbon dates, and the possibility of old wood or old charcoal mustbe considered for each situation. The old-charcoal problem wasillustrated by historic graffiti in Australia.36 “Mr. C. B. Ross”,written in charcoal in a shelter, was radiocarbon dated to 1310years BP. (BP refers to radiocarbon years before present, definedas A.D. 1950.) Because the Ross family has lived in the regiononly since the late 1800s, a more recent date was expected.However, two samples of near-surface charcoal from the shelterwere tested, yielding dates of 690 and 1470 years BP.37 Oldcharcoal was readily available from the shelter floor and wasobviously used to write the graffiti. In spite of these problemsdating charcoal paint pigments, most results obtained so far appearto be valid and accurate. In addition to charcoal, many dates havebeen obtained on beeswax images. There is little reason to doubtthe validity of the dates, but beeswax figures are found only in avery isolated area in Australia.38,39

PLASMA EXTRACTION OF ORGANIC CARBONFROM PAINTS BASED ON INORGANICPIGMENTSThe second major way of dating pictographs is to analyze theradiocarbon content of organic material that may have been addedto the paints as binders or vehicles for the pigments by the originalartists. Almost none of the colored rock art images in the worldcontain visible organic matter. When we first attempted to developa dating method, we examined the Pecos River pictographs ofsouthwest Texas, an area rich in enigmatic, polychromatic, oftenlarger-than-life images. However, charcoal was apparently not usedas a pigment in those paintings, even for black; MnO2 was usedinstead.13

The sample preparation for radiocarbon dating of charcoal isconventionally done by a strong acid wash, followed by a strongbase wash and a final strong acid wash, usually at 50-70 °C. Wewere concerned that this harsh treatment, which destroys perhaps30% of even very stable charcoal, would adversely affect theorganic carbon of unknown composition present in a paint sample.

Not knowing whether all or a substantial fraction of theunknown organic material might be removed by the harshtreatments, we selected a technique in which those treatmentswere unnecessary. We focused on extracting small amounts of

organic carbon in the paints from the far greater amounts ofinorganic carbon in the rock. We scraped a small (∼2 × 2 cm)area of the painted surface with clean dental picks or new surgicalblades. The samples were wrapped in aluminum foil and storedin plastic bags in a desiccator to await analysis. It is virtuallyinevitable that much greater amounts of calcium carbonate andcalcium oxalate are included in the scraped rock art sample thanorganic material in the paint.

We opted to extract organic carbon using low-temperature(e150 °C), low-pressure (∼ 1 torr) oxygen plasmas coupled withstatic high vacuum to isolate CO2 formed by the plasma oxidationof organic matter. Figure 4 is a schematic of a plasma apparatus.40

Radio frequency power for the plasmas was supplied by com-mercial 27.1 and 13.5 MHz generators. We ran typically at powersof 100 W or less but used higher-power plasmas to clean thesample chamber of adsorbed atmospheric CO2. Low-temperatureoxygen plasmas contain 1-2% ionized oxygen, as well as atomicoxygen, and are highly reactive with organic carbon. However,we showed that the plasma did not affect the much largeramounts of limestone and calcium oxalate;18,41 thus, we couldcleanly extract the organic carbon under very mild conditions.

Under standard operating conditions, we first ran higher power(150 W) oxygen plasmas to rid the interior of the sample chamberof organic contamination from previous runs. After multipleoxidations, the carbon background was reduced to <1 µg. Asample of a rock painting was inserted into the chamber througha blank flange. Then argon plasmas were run repeatedly on allpictograph samples to remove adsorbed CO2 from the samplesurfaces. After the amount of absorbed CO2 was reduced to<1 µg carbon as CO2 by argon plasmas, the system wasdeemed ready to begin the oxygen extractions of organiccarbon. Extraction was accomplished by 1 mtorr, 50-100 Woxygen plasmas with a bulk temperature of <150 °C. The CO2

produced was collected by freezing it in a 6 mm glass tubeunder liquid nitrogen and then heat-sealing the tube. Theresulting CO2 sample was then sent to an AMS laboratory forradiocarbon measurement.42-45

METHOD VERIFICATIONThe plasma chemical technique has seemingly produced viableand accurate dates by extracting very small amounts of organiccarbon, usually ∼70-100 µg carbon. Because this extractionmethod had never been used in radiocarbon dating, we tested itby dating nonrock art archaeological materials of known age:charcoal, Third International Radiocarbon Intercomparison (Bel-fast pine), Fourth International Radiocarbon Intercomparisonmaterials (textiles and leather), an ostrich eggshell, a series ofsamples from an infant burial (mummified) from Hinds Cave insouthwest Texas, and others.46 In all these cases, the smallamounts of organic carbon proved sufficient to get accurate dates(Figure 3). The technique clearly works well for a wide variety oforganic archaeological artifacts.

We also performed radiocarbon analyses on materials that weretoo old to contain significant radiocarbon (not shown in Figure4). Examples are albertite (coal), Axel Heiberg wood (ancientwood that is preserved but not fossilized), and commercialgraphite. Our background measurements were “insignificantcompared with the background level of 0.0009 mg modern carbonobtained at the Australian Nuclear Science and Technology

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Organisation AMS laboratory” (Ewan Lawson, personal com-munication, 1998). Lawrence Livermore National Laboratory’sCenter for Accelerator Mass Spectrometry also found no signifi-cant background in our technique when fossil carbon in plasticfibers was determined to be >49,900 radiocarbon years BP.47

As analytical chemists, we would like to date standardpictographs with known ages in order to validate the newlydeveloped method. Unfortunately, few pictographs have beenaccurately dated. Precisely this lack of knowledge about rockpainting ages motivated us to attempt to develop a datingtechnique for pictographs. We relied on contextual dating forevaluating our pictograph dates. The error margins for contextualdating are often larger than those of a single radiocarbon date.Of course, radiocarbon dating is much more accurate if severaldates are determined.

At any rate, our dates were compared with expected age rangesas inferred from five archaeological approaches (Figure 5). Theshaded rectangular bars are the estimates made on the basis ofarchaeological inference (i.e., contextual dating) to compare withour radiocarbon dates as examples. One reviewer wrote, “In anyevent, each [contextual and radiocarbon date] adds value to theother, and I would never believe a single radiocarbon date of apictograph without appropriate analysis from archaeological infer-ence.” I agree with that assessment.

Correlation with contextual dates. Pecos River paintings arethe style that we have dated most frequently (25 dates). Turpinassumed that pictographs were a ritualistic mechanism for re-lieving stress brought about by increased population densities.48-50

She argued, based on population estimates from the archaeological

record and the relationship of population density to informationstress, that ages for the Pecos River-style pictographs shouldconcentrate between ∼3000 and 4000 years BP. Radiocarbon yearsdo not correlate precisely with calendar years; a calibration isnecessary to correct radiocarbon years to calendar dates. The 14Cages determined for the Pecos River paintings generally fallwithin Turpin’s estimate of the expected age range.

Dates of nearby associated artifacts. Three examples of thiswere the All American Man, the Pryor Mountain shield figure,and the Texas bison from Painted Indian Cave.51-53 The AllAmerican Man rock painting is unique in our studies. Weextracted CO2 from a charcoal layer that dated to 750 ± 60 yearsBP. After the removal of the charcoal, we continued to extractcarbon from an underlying white layer that dated to 575 ± 70years BP, for an average of 675 ± 65 years BP. At the AllAmerican Man site, the pictograph is located in a shelter thathas remains of a typical late Pueblo II-Pueblo III westernAnasazi alcove with habitation and storage structures. Near thePryor Mountain site in Montana, test excavations into soildeposits at the base of the rock art panels produced carbonsamples from stratified layers that dated at 1270 ± 125 and 850± 50 years BP. Our date for the pictograph at the PryorMountain site was essentially in perfect agreement with theyounger of those cultural levels excavated.52

For the bison pictograph at Painted Indian Cave, we obtaineda radiocarbon date of 770 ± 50 years BP.53 Ricklis conducted fourradiocarbon assays on bison bones from the Coastal Plain site41RF21 that provide dates on bison availability: 750 ± 100, 720 ±190, 790 ± 70, and 760 ± 130.54 Huebner concluded that bison

Figure 4. Schematic of the plasma chemical system. (Adapted with permission from Ref. 40.)


reentered the lower plains of Texas near 750 years BP after morethan 1500 years of absence.55 It is not likely to be a coincidencethat these earliest dates for bison reentry onto the southern plainsof Texas statistically overlap with the date of 770 ± 50 years BPthat we obtained for the Painted Indian Cave pictograph. It seemslikely that the author of the bison pictograph recorded an earlysighting of bison in the area. This is the only bison image in Texasthat has been radiocarbon dated to the Late Prehistoric period.

At Hueco Tanks, Texas, we obtained nine dates ranging from740 ± 50 to 1350 ± 160 years BP for black-charcoal-pigmentedpictographs.56,57 Six of the nine dates, with two duplicates,obtained at this location were older than had been expected byone investigator (<1000 years BP).58 Because these were charcoalpigments, we are confident that our radiocarbon dates are correct,in spite of the fact that six of our dates were older than thearchaeologically inferred age range of <1000 years BP. And, infact, our dates overlap with occupation dates for pit-housesexcavated nearby and at Hueco Tanks.59,60

Iconography. Different styles of rock art may contain iconog-raphy that places them in different time periods. For example,the Pecos River-style paintings show multiple instances of spearthrowers, whereas two other styles (Red Linear and Red Mono-chrome) in the same region show images of bows and arrows, amuch more recent form of weaponry in southwest Texas.48-50

Furthermore, more stringent constraints on the chronology canbe assigned by dating excavated artifacts like those shown in the

paintings. We measured two radiocarbon dates on the 1-10 cmRed Linear-style red stick figures. They were in agreement withone another at 1280 ± 45 and 1280 ± 80 years BP.61,62 Thearchaeologically inferred age range for this style was very wide,ranging from 1250 to 3000 years BP, based on superposition.48-50

The dates found would place the style near the beginning of thatrange, and once again, the similarity of the two ages supportsthe validity of the plasma technique.

From Picture Cave #1 in Missouri, five dates ranging from 940± 80 to 1090 ± 90 years BP were obtained from various charcoaldrawings.63-65 The short span of time covered indicates a briefperiod of painting, possibly even a single episode. The two mostdistinguishable drawings are Piasa (an underwater spirit that is acommon icon of the Eastern Woodlands) with an estimated ageof ca. 800-950 years BP and the long-nosed god maskette panelthat, before direct dating, was estimated to date to as early as800-1050 years BP.66 These two estimated age ranges overlapwith the five dates we obtained on these and other images in thesame panel.

For an Angola rock painting, the archaeologist involved spokealmost no English, and I spoke no Portuguese, so communicationwas a serious problem.67 However, he indicated that he expectedthe age to be ∼2000 years old based on iconography. More detailsare lacking, and we have lost communication with each other.The average of three dates we obtained was 2010 ± 90 years BP,which is consistent with his estimate of the expected age.

Figure 5. Overall general agreement of our dates with age ranges expected from archaeological inference or from previously determined ageson related materials. The triangles are our radiocarbon dates; the numbers in parentheses are the numbers of our dates on given samples.(Drawn by Kyle Rowe.)


Historical information. In two instances, archaeologistsprovided us with the historical ages of paintings. An Egyptianpottery shard from Tel el-Amarna, Egypt, had a historic date of1340 ± 15 B.C.68 Our radiocarbon date, 2980 ± 80 years BP,corresponds to a calendar range of 1380-890 B.C. Our date, whenconverted to a calendar date range, overlapped with the knownage at ±2σ. Radiocarbon ages were determined on three hiero-glyph texts from images that contained a Mayan calendar date inNaj Tunich Cave in Guatemala. Even with the potential problemsin dating those pictographs, our dates still fell only 108 years onaverage from the ascribed calendar dates. It is, of course, alsopossible that either our dates or the Mayan dates are in error by108 years or so.69

Style analysis. Most areas of the world contain rock art thatis identifiable as a distinct style of painting. Different styles maycontain iconography that constrains them to different time periods.One then expects, for example, that all Pecos River-style paintingsin southwest Texas are constrained to a similar time periodbecause all have images of spear throwers. All pictographs of otherstyles in the region (Red Linear and Red Monochrome) can beattributed to a more recent time regime because of the presenceof bows and arrows.48-50 The painting for which style was themost prominently used to ascertain its age was at Le Portel,France.70 By looking at the ages of similar-style pictographs inother caves around France and Spain, researchers have estab-lished the range of radiocarbon dates for that style as 11,700-13,800years BP. Our ages of 11,600 and 12,180 years BP agreed withthose dates. We were also attempting to measure very smallsamples that were 10-100× smaller than samples from the otherpaintings.

Despite these instances, there are too few cases in which theaccuracy of the archaeological inferences is adequate for theiruse as precise standards. Nonetheless, our radiocarbon dates onseveral samples compared well with the ages expected fromarchaeological inference, as demonstrated in Figure 5. The datain Figures 3 and 5 provide confidence that the plasma chemicalapproach to radiocarbon dating is a viable technique and, underfavorable conditions, is suitable for dating pictographs.

Unfortunately, there has been virtually no independent con-firmation of the plasma chemical method by other techniques.Until that happens, one must keep an open mind about theaccuracy and validity of this approach. In the few examples inwhich other researchers have radiocarbon dated rock paintingsthat had inorganic pigments, no experimental details describingthe procedure were provided and/or no verification studies weredone that compared their dates with contextual dates fromarchaeological inference.71-74

DISCUSSION

We have dated pictographs from numerous countries around theworld: Angola, Australia, Belize, Brazil, France, Guatemala,Mexico, Russia, and Spain. In the U.S., we have dated pictographsfrom Arizona, California, Colorado, Idaho, Missouri, Montana,Texas, Utah, and Wisconsin. Although not all of these wereconstrained by archaeological inference well enough to beincluded in Figure 5 as support of the plasma chemical method,they may nevertheless be worth mentioning.

Sometimes, the radiocarbon dates on the samples did not agreewith the contextual dates based on archaeological inference. Oneprominent example was on a rock art panel in Fern Cave, LavaBeds National Monument (California; Figure 6), which wasthought to depict the A.D. 1054 supernova explosion that wasvisible to the naked eye. The appearance of a new star was notedhistorically in Oriental and Middle Eastern writings. However,radiocarbon dates on three of the figures, 230 ± 70, 330 ± 50, and840 ± 70 years BP, were much too young for the images to haverepresented that event.41

Similarly, there were two other instances in which the plasmachemical dates differed significantly from those based on archaeo-logical inference. However, these dates were obtained on charcoal-pigmented drawings, and we have no reason to suspect theradiocarbon dates.75,76 In addition, the plasma chemical techniqueprovides a means of conducting nondestructive radiocarbon analysisonperishableorganicartifactssuchasleather,grass,andtextiles.77-80Thetechnique also has the ability, although not yet tested, to obtainradiocarbon dates as a function of depth in these kinds of artifacts.

Recently Mori et al. reported a new technique for dating rockart.81 They separated the amino acids and selectively dated ahydrolyzed fraction. This technique may hold great promisebecause it has the advantage that the dated material is chemicallycharacterized. The date obtained, 6145 ± 70 years BP, agreed withthe date expected on the basis of contextual archaeologicalinference, 5500-7500 years BP.

Figure 6. This rock art panel shows charcoal drawings of a circlenear what may be a crescent moon, an image that had beensuggested as a recording of the A.D. 1054 supernova explosion thatwas visible to the naked eye for almost 2 years. The scale is 10 cm.41


CONCLUSIONSWithout some idea of the antiquity of images, they are impossibleto integrate into cultural history in a given area and difficult touse in addressing broader issues of cultural processes. It hasproven very difficult to directly date most rock art images.

Radiocarbon age determinations obtained at Texas A&MUniversity during the past 15 years or so indicate that the plasmachemical/accelerator MS technique for determining the ages forpictographs produces reliable results. It is directly applicable topictographs that have been painted with carbon-bearing, inorganiciron and manganese oxides/hydroxides, as well as with charcoal.Organic carbon in the basal rock and mineral accretions associatedwith pictographs are the major remaining impediments to ourtechnique routinely giving accurate and reliable ages, along withthe uncertainty of the identity of the materials being dated. If thebackground can be reduced or removed, this new technique couldprovide archaeologists with ever more reliable and accuratechronological information. No other approach currently used fordating pictographs is as generally applicable as the plasmachemical method. Nor has any other technique been tested aswe have done for our dates on paintings with inorganic pigments(Figures 3 and 5). Many dates for pictographs have now beenmeasured and documented with our technique in the archaeologi-cal research literature.

Rock art depicts, albeit in exceedingly enigmatic ways, thecosmological world of native peoples: how they lived, what theybelieved, and how they saw themselves in relation to their world.The images are virtually always more than just doodling or graffiti.The anticipated understanding of what prompted the artists tocreate their art compels us to study rock art as a serious endeavor.

But only by assigning painted images to a particular timeperiod, and thus a prehistoric culture, can archaeologists gaininformation on the artistic, cultural, technical, and religious aspectsof particular cultural groups. Significant progress has been madein the radiocarbon dating of rock paintings. Because of the priorlack of methods for dating rock art, archaeologists had typicallyalmost completely ignored it before the 1990s. But with the abilityto obtain reliable radiocarbon dates on pictographs, archaeologistshave now begun to incorporate rock art into a broader study thatincludes other cultural remains.

ACKNOWLEDGMENTI acknowledge the support of my former graduate students

who were associated with this dating work: Jon Russ, ScottChaffee, Wayne Ilger, E. Joe Mawk, Ann Miller, Mary Pace, RuthAnn Armitage, and Karen Steelman. In addition, I would like tothank the following archaeologists, AMS experts, and rock artspecialists who collaborated with us: Charles Barat, Lucrecia deBatres, Michael Bies, Robert Boszhardt, Thomas Boutton, JamesBrady, Jane Childress, Allan Cobb, Sally Cole, Nancy Coulam,Bruno David, Carl Davis, M. Dauvbois, Carol Diaz-Granados,James Duncan, Marlene Garnicia, J. Gavira, Neide Guidon, TomGuilderson, John Head, Antonio Hernanz, Richard Hill, CharlesHixson, Kathleen Hogue, Q. Hua, Geraldine Jacobsen, Jim Keyser,Jane Kolber, Joe Labadie, Ewan Lawson, Lawrence Loendorf,Robert Mallouf, Martı Mas, Patricia McAnany, Michel Menu,Carolynn Merrill, Priscilla Murr, Laura Nightingale, MargaretNobbs, Polly Peterson, Jane Pike, F. Carrera Ramırez, EugeniaRobinson, Juan Ruiz, Alan Schroedl, Sara Scott, Harry Shafer,

Vladimir Shirokov, John Southon, Kay Sutherland, Claudio Tuniz,Solveig Turpin, R. Fabregas Valcarce, J. Vezian, and P. Walter. Iam very appreciative of the more than two decades of collaborationwith Marian Hyman on this and other research. Two reviewersoffered comments that significantly improved this paper, as didTrish Seapy and Kathleen Rowe.

Marvin W. Rowe is a professor at Texas A&M University College Stationand Qatar. He applies his research to archaeological problems, specificallyradiocarbon dating of ancient rock paintings, the development ofnondestructive radiocarbon dating of perishable artifacts, and the use ofnondestructive portable X-ray fluorescence to analyze pigments in rockpaintings and on ceramic decorations. Address correspondence to him at1630 Villa Strada, Santa Fe, NM 87506 ([email protected]).

REFERENCES(1) Rowe, M. W. In Discovering North American Rock Art; Chippindale, C.,

Whitley, D. S., Loendorf, L. L., Eds.; University of Arizona Press: Tucson,AZ, 2005; pp 241-263.

(2) Whitley, D. S.; Loendorf, L. L. In New Light on Old Art: Recent Advances inHunter-Gatherer Rock Art Research, Monograph 36; Whitley, D. S.,Loendorf, L. L., Eds.; Los Angeles Institute of Archaeology, University ofCalifornia: Los Angeles, 1994; pp xi-xx.

(3) Anderson, E. C.; et al. Science 1947, 10, 576–577.(4) Arnold, J. R.; Libby, W. F. Science 1949, 110, 678–680.(5) Muller, R. A. Science 1977, 196, 489–494.(6) Nelson, D. E.; et al. Science 1977, 198, 507–508.(7) Bennet, C. L.; et al. Science 1977, 198, 508–509.(8) Elmore, D.; Phillips, F. M. Science 1987, 236, 543–550.(9) Finkel, R. C.; Suter, M. In Analytical Geochemistry; Hyman, M., Rowe, M. W.,

Eds.; JAI Press: Greenwich, CT, 1993; Vol. 1, pp 1-114.(10) Vogel, J. S.; et al. Anal. Chem. 1995, 67, 353 A-359 A.(11) Hedges, R. E. M.; et al. Archaeometry 1987, 29, 289–306.(12) Van der Merwe, N. J.; Sealy, J.; Yates, R. S. Afr. J. Sci. 1987, 83, 56–57.(13) Hyman, M.; Turpin, S. A.; Zolensky, M. E. Rock Art Res. 1996, 13, 93–

103.(14) Ilger, W. I.; et al. Radiocarbon 1995, 37, 299–310.(15) Hyman, M.; Rowe, M. W. Techne 1997, 5, 61–70.(16) Russ, J.; et al. Nature 1990, 348, 710–711.(17) Steelman, K. L.; et al. In Archaeological Chemistry: Materials, Methods, and

Meaning; Jakes, K. A., Ed.; ACS Symposium Series 831; American ChemicalSociety: Washington, DC, 2002; pp 22-35.

(18) Russ, J.; Hyman, M.; Rowe, M. W. Radiocarbon 1992, 34, 867–872.(19) Chaffee, S. D.; Hyman, M.; Rowe, M. W. In New Light on Old Art: Recent

Advances in Hunter-Gatherer Rock Art Research, Monograph 36; Whitley,D. S., Loendorf, L. L., Eds.; Los Angeles Institute of Archaeology, Universityof California: Los Angeles, 1994; pp 9-12.

(20) Rowe, M. W. In Discovering North American Rock Art; Chippindale, C.,Whitley, D. S., Loendorf, L. L., Eds.; University of Arizona Press: Tucson,AZ, 2005; pp 294-319.

(21) Valladas, H.; Cachier, H.; Arnold, M. Rock Art Res. 1990, 7, 18–19.(22) Clottes, J.; Courtin, J. The Cave Beneath the Sea: Paleolithic Images at

Cosquer; Abrams: New York, 1996.(23) Clottes, J.; Courtin, J.; Collina-Girard, J. Int. Newsl. Rock Art 1996, 15,

1–2.(24) Clottes, J.; et al. Antiquity 1997, 71, 321–326.(25) Clottes, J. In The Archaeology of Rock Art; Chippindale, C., Tacon, P. S. C.,

Eds.; Cambridge University Press: Cambridge, U.K., 1998; pp 112-129.(26) Valladas, H.; et al. Revue d’Archeometrie Suppl. 1999, 39-44.(27) Valladas, H.; et al. Nature 2001, 413, 479.(28) Valladas, H.; et al. Radiocarbon 2001, 43, 977–986.(29) Valladas, H. Meas. Sci. Technol. 2003, 14, 1487–1492.(30) Valladas, H.; Clottes, J. Antiquity 2003, 77, 142–145.(31) Clottes, J., Courtin, J.; Vanrell, L. Cosquer Redecouvert; Le Seuil: Paris, 2005.(32) Schiffer, M. B. J. Archaeol. Sci. 1986, 13, 13–30.(33) Bednarik, R. G. Prehistoire Anthropologie Mediterraneennes 1994, 3, 95–

102.(34) Bednarik, R. G. Int. Newsl. Rock Art 1994, 7, 16–18, 26-27.(35) Bednarik, R. G. Archaeometry 1996, 38, 1–13.(36) David, B.; et al. Archaeol. Oceania 1999, 34, 103–120.(37) David, B. Queensl. Archaeol. Res. 1990, 7, 73–94.(38) Nelson, D. E.; et al. Archaeometry 1995, 37, 151–156.(39) Nelson, D. E.; Southon, J. R.; Takahashi, C. The Beeswax Rock-Art of Northern

Australia [CD-ROM]; Anthropology Department, Simon Fraser University:Burnaby, Canada, 2000.


(40) Rowe, M. W.; Steelman, K. L. Am. Lab. 2002, 34, 15–19.(41) Armitage, R. A.; et al. Antiquity 1997, 71, 715–720.(42) Russ, J.; et al. Plasma Chem. Plasma Process. 1991, 11, 515–527.(43) Chaffee, S. D.; et al. Am. Antiquity 1994, 59, 769–781.(44) Ilger, W. A.; et al. Radiocarbon 1995, 37, 299–310.(45) Steelman, K. L.; et al. Antiquity 2005, 79, 1–11.(46) Steelman, K. L.; et al. Am. Antiquity 2004, 69, 741–750.(47) Miller, A.; et al. Mexicon 2002, 24, 79–81.(48) Turpin, S. A. Plains Anthropol. 1984, 29, 181–197.(49) Turpin, S. A. Bull. Tex. Archeol. Soc. 1986, 55, 123–144.(50) Turpin, S. A. Am. Indian Rock Art 1990, 16, 99–122.(51) Chaffee, S. D.; et al. Am. Antiquity 1994, 59, 769–781.(52) Chaffee, S. D.; et al. Plains Anthropol. 1994, 39, 195–201.(53) Brock, E.; et al. Plains Anthropol. 2006, 51, 199–205.(54) Ricklis, R. A. Tex. Archeol. 1989, 33, 12–13.(55) Huebner, J. A. Plains Anthropol. 1991, 36, 343–358.(56) Hyman, M.; et al. Rock Art Res. 1999, 16, 75–88.(57) Rowe, M. W. In Archaeology between the Borders; Thompson, M., Jurgena,

J., Jackson, L., Eds.; El Paso Museum of Archaeology: El Paso, TX, 2005;pp 89-94.

(58) Schaafsma, P. Indian Rock Art of the Southwest; University of New MexicoPress: Albuquerque, NM, 1980.

(59) Kegley, G. B. In Jornada Mogollon Archaeology: Proceedings of the FirstJornada Conference; Beckett, P. H., Wiseman, R. N., Eds.; New Mexico StateUniversity: Las Cruces, NM, 1979, pp 19-25.

(60) Whalen, M. E. Turquoise Ridge and Late Prehistoric Residential Mobility inthe Desert Mogollon Region; University of Utah Anthropological Papers 118;University of Utah Press: Salt Lake City, UT, 1994.

(61) Ilger, W. A.; Hyman, M.; Rowe, M. W. Bull. Tex. Archeol. Soc. 1995, 65,337–346.

(62) Rowe, M. W. Bull. Tex. Archeol. Soc. 2003, 74, 83–88.(63) Diaz-Granados, C.; et al. Am. Antiquity 2001, 66, 481–492.(64) Rowe, M. W. Unpublished data, 2005.(65) Diaz-Granados, C.; Duncan, J. R. The Petroglyphs and Pictographs of Missouri;

University of Alabama Press: Tuscaloosa, AL, 2000.

(66) Diaz-Granados, C. The Petroglyphs and Pictographs of Missouri: ADistributional, Stylistic, Contextual, Functional, and Temporal Analysis ofthe State’s Rock Graphics, Vols. I, II. Ph.D. Dissertation, WashingtonUniversity St. Louis, 1993.

(67) Guttierez, M. Personal communication, 1993.(68) Brier, R. C. W. Post Campus of Long Island University, Brookville, NY.

Personal communication, 1997.(69) Armitage, R. A.; et al. Am. Antiquity 2001, 66, 471–480.(70) Ilger, W.; et al. Prehistoire Ariegeoise 1995, 50, 231–236.(71) Watchman, A. In The Bradshaws; Walsh, G., Ed.; Takarrakka Rock Art

Centre: Queensland, Australia, 2000; pp 38-41.(72) Morwood, M. J.; Hobbs, D. In Quinkan Prehistory: The Archaeology of

Aboriginal Art in S. E. Cape York Peninsula, Australia, Tempus 3; Cole,N. A., Watchman, A., Eds.; Anthropology Museum, University of Queens-land Press: St. Lucia, Australia; pp 147-159.

(73) Watchman, A. In Aboriginal Rock Art of the Kimberley; Kenneally, K. F., etal., Eds.; Occasional paper No. 1; Kimberley Society: Perth, WesternAustralia, 1997; pp 39-46.

(74) Watchman, A.; et al. Rock Art Res. 1997, 14, 18–26.(75) Steelman, K. L.; et al. MidCont. J. Archaeol. 2001, 26, 121–131.(76) Steelman, K. L.; et al. Antiquity 2002, 76, 341–348.(77) Steelman, K. L.; Rowe, M. W. In Archaeological Chemistry: Materials,

Methods, and Meaning; Jakes, K. A., Ed.; ACS Symposium Series 831;American Chemical Society: Washington, DC, 2002; pp 8-21.

(78) Steelman, K. L.; Rowe, M. W. In 14C and Archaeology: Proceedings of theFourth Symposium, Oxford; Higham, T., Bronk Ramsey, C., Owen, C., Eds.;Oxbow Books: Oxford, U.K., 2004; pp 35-42.

(79) Steelman, K. L.; et al. Am. Antiquity 2004, 69, 741–750.(80) Rowe, M. W. Non-Destructive and Microanalysis for the Diagnostics and

Conservation of the Cultural and Environmental Heritage [CD-ROM]; Paper#155; University of Lecce: Lecce, Italy, 2005; pp 1-13.

(81) Mori, F.; et al. J. Cult. Herit. 2006, 7, 344–349.

AC802555G


radiocarbon dating of ancient rock paintings

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