Middle East coastal ecosystem response tomiddle-to-late Holocene abrupt climate changesD. Kaniewski*†‡, E. Paulissen§, E. Van Campo*, M. Al-Maqdissi¶, J. Bretschneider�, and K. Van Lerberghe�

*ECOLAB - Laboratoire d’Ecologie Fonctionnelle, Universite Paul Sabatier-Toulouse 3, Unite Mixte de Recherche 5245 Centre National de la RechercheScientifique, Institut National Polytechnique de Toulouse, 29 Rue Jeanne Marvig, 31055 Toulouse, France; †Center for Archaeological Sciencesand §Physical and Regional Geography Research Group, Katholieke Universiteit Leuven, Celestijnenlaan 200E, 3001 Heverlee, Belgium;¶Directorate-General of Antiquities, Damascus, Syria; and �Near Eastern Studies Unit, Katholieke Universiteit Leuven, FaculteitLetteren, Blijde-Inkomststraat 21, 3000 Leuven, Belgium

Edited by Ofer Bar-Yosef, Harvard University, Cambridge, MA, and approved July 16, 2008 (received for review April 11, 2008)

The Holocene vegetation history of the northern coastal ArabianPeninsula is of long-standing interest, as this Mediterranean/semiarid/arid region is known to be particularly sensitive to cli-matic changes. Detailed palynological data from an 800-cm alluvialsequence cored in the Jableh plain in northwest Syria have beenused to reconstruct the vegetation dynamics in the coastal low-lands and the nearby Jabal an Nusayriyah mountains for the period2150 to 550 B.C. Corresponding with the 4.2 to 3.9 and 3.5 to 2.5cal kyr BP abrupt climate changes (ACCs), two large-scale shifts toa more arid climate have been recorded. These two ACCs haddifferent impacts on the vegetation assemblages in coastal Syria.The 3.5 to 2.5 cal kyr BP ACC is drier and lasted longer than the 4.2to 3.9 cal kyr BP ACC, and is characterized by the development ofa warm steppe pollen-derived biome (1100–800 B.C.) and a peak ofhot desert pollen-derived biome at 900 B.C. The 4.2 to 3.9 cal kyrBP ACC is characterized by a xerophytic woods and shrubs pollen-derived biome ca. 2050 B.C. The impact of the 3.5 to 2.5 cal kyr BPACC on human occupation and cultural development is importantalong the Syrian coast with the destruction of Ugarit and thecollapse of the Ugarit kingdom at ca. 1190 to 1185 B.C.

pollen-derived biomes � Tell Tweini � Syria � bond events

The Levantine part of the Arabian Peninsula is extremely richin archaeological sites, and therefore well suited to study the

relationships between natural environment and human societies.High-resolution middle-to-late Holocene terrestrial palaeo-records are still rare in this area. In this article, the impacts ofclimate forcing and human pressure on past vegetation wereevaluated through the reconstruction of ecosystem dynamics inthe climatically sensitive zone of coastal Syria (Fig. 1). The studyarea is located in the Fertile Crescent, at the transition betweenMediterranean and subtropical climates. The coastal lowlandsare separated from the Ghab depression to the east by the Jabalan Nusayriyah, a 140-km long north-south mountain range 40- to50-km wide with peaks �1,200 m above sea level (asl).

Previous studies (1–6) have defined two abrupt climatechanges (ACCs) in the Middle East between 3050 and 50 B.C.The first ACC is generally referred as the 4.2 cal kyr BP aridevent, covering an estimated time period of 4200 to 3900 cal yearBP (2250–1950 B.C.) worldwide (7). During this ACC, a wide-spread abandonment of the agricultural plains of northernMesopotamia (2, 8) is noted. It corresponds with the abruptcollapse of the northern provinces of the Akkadian Empire at4170 � 150 years BP (9, 10, 11), with the termination of the urbanHarrapan civilization in Pakistan (12), the collapse of the OldKingdom in Egypt (2150 B.C.) (13), and the abandonment ofcities and towns in Palestine (14), in western Syria (15), and alongthe Euphrates (5). The second is the 3.2 cal kyr BP ACC,covering an estimated time period of 3500 to 2500 cal years BP(1550–550 B.C.) worldwide (7). It has drawn less attentiondespite the collapse of the Ugarit kingdom at ca. 1190 to 1185B.C. (16) and the fall of Hellenistic, Anatolian, and Levantine

coastal cities all attributed to the invasions of the so-called ‘‘SeaPeople’’ (17).

At the end of the late Bronze Age, archaeological evidenceshows a massive devastation in western Asia, and most of thecities in Anatolia, Syria, and Palestine were destroyed at ca. 1200B.C. This regional decline was potentially caused by a successionof catastrophic droughts, followed by economic collapse andsocial chaos (17). A Dead Sea level drop beneath �390 m belowsea level (bsl) (3, 4). and increased �18O values along the EasternMediterranean coast (2, 18) and in the Soreq Cave (1) confirmdrier climatic conditions during the same period, strengtheningthe climate hypothesis. As past ACCs have been put forward asthe main driving forces modulating urbanization and humanbehavior in the ancient Fertile Crescent (4, 5, 9), this article aimsto detail the environmental impact of the 3.5 to 2.5 cal kyr BPACC in the Middle East.

Jableh is a Syrian coastal town (see Fig. 1) located 28-km southof the modern harbor of Latakia and 40-km south of the ancientfamous port city of Ugarit in ancient northern Phoenicia (16).The pear-shaped Tell Tweini (35°22�17.93�� N, 35°56�12.60�� E,elevation: 19 to 27 m asl, surface: 11.6 ha), the potential BronzeAge harbor town of Gibala, lies east of Jableh at �1.75 km fromthe seashore. Gibala is mentioned for the first time in an Ugariticdocument (Akkadian tablet PRU 4, 71–76) from the second halfof the 14th century B.C., when Niqmepa was king in Ugarit(1350–1300 B.C.). This tablet suggests that Gibala belonged tothe state of Ugarit (19). Gibala has also been mentioned later inan Assyrian text of Tiglatpileser III (ca. 738 B.C.).

Author contributions: D.K. and E.P. designed research; D.K. performed research; D.K., E.P.,E.V.C., M.A.-M., J.B., and K.V.L. analyzed data; and D.K., E.P., and E.V.C. wrote the paper.

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

‡To whom correspondence should be addressed. E-mail: kaniewsk@cict.fr.

© 2008 by The National Academy of Sciences of the USA

Fig. 1. The northern Arabian Peninsula with the geographical location ofJableh, Tell Tweini-Gibala, and the Rumailiah alluvial plain with core TW-1.

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An 800-cm detailed pollen record from the alluvial deposits ofthe Rumailiah river, just north of Gibala-Tell Tweini (see Fig. 1),supported by a chronology based on four AMS 14C age deter-minations on charred plant macroremains, was used to decipherthe specific environmental conditions prevailing in northwestSyria during the middle-to-late Holocene. Pollen data have beenconverted to plant functional types (PFTs) and to pollen-derivedbiomes (PdBs) (20, 21) with the aim to evaluate the impact ofthese consecutive ACCs on ancient coastal ecosystems and todetail the 3.5 to 2.5 cal kyr BP dry event.

Climate. The Syrian coastal lowland enjoys a typical Mediterra-nean climate with cool, wet winters and hot, dry summers. Themean annual temperature and precipitation recorded at Latakia(35.5 N, 35.8 E, 7 m asl, 1960–1990) are 19.5°C and 811.4 mm.The cumulated rainfall amounts from June to September are�17 mm. During winter, precipitation mainly originates fromeastward propagating, midlatitude cyclones generated in theNorth Atlantic and in the eastern Mediterranean Sea. Thenorth-south orientated Jabal an Nusayriyah mountain rangeaffects the precipitation amounts positively in the coastal areaand negatively inland. During the summer, the area is influencedby the subtropical high-pressure system, which almost com-pletely inhibits rainfall.

Results and DiscussionNumerical Analyses. Principal components analysis (PCA) ordi-nation was selected because it is a nonparametric method ofextracting relevant information from complex datasets (Fig. 2).Most of the variance is accounted for the first PCA-Axis, with68.38% of total inertia. PCA-Axes 2 and 3 account for 18.04%and 7.53% of total inertia, respectively. PCA-Axis 1 loadingsdistribute the PdBs classified as steppe-desert with hot desert(HODE) (0.6181) and warm steppe (WAST) (0.1832) in positivevalues. The negative values correspond to the PdBs classified aswoods-forest with warm mixed forest (WAMX) (�0.6512) andxerophytic woods/shrubs (XERO) (�0.1219). Linear detrendedcross-correlations were applied to distinguish the positive ornegative PdB-responses with selective incidences. Human-induced changes of PdBs classified as woods-forest to PdBsclassified as steppe-desert (Fig. 3) may be reflected by a signif-icant correlation coefficient at lag 0 (P � 0.05) and positive lagsin cross-correlation results between the primary anthropogenicindicators and the PdBs classified as steppe-desert (� 8 sam-ples, � 200 calibrated year window). No positive correlation wasobserved between both variables in the time-window, suggestingno direct relationships between human pressure and the intro-duction of a WAST landscape in the Syrian coastal area.

The PCA-Axis 1 ordination of the TW-1 data (see Fig. 2)therefore relates different vegetation assemblages according toACC-related variations in moisture availability through time: (i)Three major positive deviations on the PCA-Axis 1 indicative ofdry periods have been recorded: before ca. 2100 B.C., during thetime period 1175 to 800 B.C., and from ca. 600 B.C. onwards. The1175 to 800 B.C. dry event does not remain stable: drynessintensity increases through time and an �50 year negativedeviation suggests a short-term humidity trend. (ii) Two mainnegative deviations of PCA-Axis 1, indicative of wetter periods,have been recorded at ca. 1950 to 1175 B.C., with humidity peaksca. 1250 B.C. and ca. 800 to 600 B.C.

PdB Diagram. Based on the PdB-scores (see Fig. 2), environmen-tal changes in the Syrian coastal area throughout the 2150 to 550B.C. period are subdivided into five major time stages. Only thetwo ACCs are considered.

Stage 1 (4.2–3.9 cal kyr BP ACC). The base of the pollen sequenceis situated within the 4.2 to 3.9 cal kyr BP ACC and shows a local

semiarid vegetation, with positive PCA-Axis 1 scores and adominant XERO PdB. Synchronous high WAMX and XEROPdB-scores (see Fig. 2) in stage 1 suggest an integration in thepollen assemblages of the altitudinal gradient of biomes betweenthe coast and the wetter Jabal an Nusayriyah mountains. Duringthis ACC, the vegetation of coastal Syria appears to be more aridthan what is registered on average in the pollen record, aprobable ecological response to lower winter precipitation thantoday. The forest cover (maximum 55% of the total pollen sum)is mainly composed of xerophytic shrubs and thorny scrubs(maximum recorded values: trees, 17%; shrubs, 46% of the totalpollen sum) resulting in a shrubby landscape without loss ofterrestrial plant diversity. The input of freshwater (IoF) and theincreased water availability (Iwa) indices are low, suggesting lowwater amounts in the Jableh area.

The 4.2 to 3.9 cal kyr BP ACC has been registered worldwide,but is mainly documented at middle and low latitudes (5, 7, 22).In the Middle East and in southern Asia its importance has beenstressed in northeast Syria at Tell Leilan, the ancient city ofShekhna (9), and in the Indus Valley (12). The agricultural plainsbetween the Tigris and Euphrates rivers were subjected to animportant shift toward aridity at 4170 � 150 year BP (9, 11), withpopulation migrations toward the south of ancient Mesopota-mia. This event, known as the ‘‘collapse of the Akkadianempire’s northern provinces’’ (23), is reflected at Tell Leilan byan important accumulation of windblown silts (24). A marinesediment core from the Gulf of Oman (25) documents an abruptincrease in aeolian dust possibly blown in from Mesopotamia at4025 � 125 calendar year BP. This ACC is also reflected by anenhanced salinization of the Indus delta and is correlated withthe end of the urban Harrapan civilization in Pakistan (12). Apronounced arid event in Lake Awafi (Rub’al-khali desert) isevidenced at 2150 B.C. (8). A dramatic drop of the Dead Sealevel (�45 m) starts at ca. 2250 B.C. (3). Lower precipitationamounts in the southern Levant (1), brine sediments from thenorthern Red Sea (26), �13C and �18O data from Gobekli Tepe(27) and Lake Zeribar (28), all point toward a shift to more aridconditions in western Asia during the time period ca. 2250 to2050 B.C. Evidence of desertion of urban centers and cities isparticularly impressive in Palestine between 2350 and 2000 B.C.,whereas northwards many cities were destroyed (29).

In coastal Syria, the history of nearby towns appears to becomplex. Gibala-Tell Tweini was inhabitated during the end ofthe third millennium B.C. [early Bronze Age (EBA) IVA–B] asattested by two architectural phases (Tweini XA–XB) (19). AtTell Sianu, 6-km north of Tell Tweini, large urban structures areknown from the EBA IVA, whereas the EBA IVB correspondsto an abandonment phase (30). At Ugarit, a hiatus at the end ofthe EBA is also registered between archaeological levels III andII (16). In the Jableh record, the beginning of this ACC is notdated, but its termination corresponds with the onset of theincrease of the WAMX PdB-scores dated at ca. 1950 B.C.

Stage 3 (3.5–2.5 cal kyr BP ACC). After �800 years of wetterconditions, inferred from the increases in PdB, classified asforest, a new trend to more arid conditions is initiated in theSyrian coastal area by the fall of WAMX PdB-scores and arenewed increase of XERO PdB-scores dated at ca. 1175 B.C.(see Fig. 2).

Contemporaneous with this major shift in vegetation assem-blages, the Ugarit kingdom collapsed at 1190 to 1185 B.C. (16),the Egyptian presence in the Levant ended ca. 1150 to 1135 B.C.(31), Assyria and Babylonia suffered from famine (32), whereascity abandonment, social chaos, and invasions of the Sea Peopleare noted in the Levant (17). In general, the 12th Century BC wasa time of crisis in the Mediterranean as many civilizationsdisappeared and towns were destroyed (33).

The characteristics of the 3.5 to 2.5 cal kyr BP worldwide ACC

13942 � www.pnas.org�cgi�doi�10.1073�pnas.0803533105 Kaniewski et al.

are clearly depicted in the evolution of the PCA-Axis 1 scores(see Fig. 2), demonstrating a gradual intensifying pulse-by-pulseresponse of the vegetation (XERO, WAST, HODE) to increas-ing drought from 1175 B.C. onwards. The full development of

desert conditions is evidenced by the intense final peak of theHODE PdB-score at 900 B.C. The vegetation responds with adramatic reduction of the forest cover, an opening of thelandscape (AP �25% of the total pollen sum), and a loss of

TELL TWEINI - Coastal Jableh plain - NW Syria

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Fig. 2. Tell Tweini: Core TW-1 linear age-scale pollen-derived biomes diagram with salinity/aridity (SI), input of freshwater (IoF) and increased water availability(Iwa) indices. �18O data originate from the Soreq Cave (1) and from the Ashdod coast (14). The atmospheric �14C curve (32) and North Atlantic Bond events (8)are plotted to match the Jableh plain pollen data with global climatic changes.

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terrestrial plant diversity. This drought is also evidenced by thesalinity/aridity-index (SI), IoF, and Iwa indices.

A small magnitude 50-year shift (ca. 1000–950 B.C.) towardwetter conditions within stage 3 is evidenced by a negativedeviation in PCA-Axis 1, lower SI, and increased IoF indices.Synchronous increases of the WAMX and XERO PdB-scoressuggest higher inputs of freshwater in the coastal area and theJabal an Nusayriyah mountains.

A dry and warm climate dated ca. 1200 to 900 B.C. has beenalso suggested for the Middle East (34). A �18O study in thesoutheastern Mediterranean (2, 18) suggests that aridification,reflected by enhanced evaporation rates, started at 1050 B.C.,succeeding by a 1650 to 1050 B.C. humid phase. This climaticshift can be correlated with changes in atmospheric moistureover India (35) and low lake levels in Turkey (36). Peaking valuesof arid/saline Chenopodiaceae and a collapse of agriculture atca. 1050 to 850 B.C. in the Ze’elim and Ein Feshkha pollensequences (6) also reflect dry conditions. The onset of anaridification is recorded in the Arabian Sea somewhat earlier, atca. 1150 B.C. (37) and much earlier, at ca. 1550 B.C. in the DeadSea, where it is reflected by low lake levels (until �417 m bsl) anda windblown sand layer at the lake bottom (4).

The data related to the 3.5 to 2.5 cal kyr BP global ACCsuggest along the Syrian coast a complex shift from an opendeciduous forest toward a more arid/saline-tolerant vegetationcover, which starts at ca. 1175 B.C. and peaks ca. 900 B.C.(2750 � 40 14C BP). The collapse of the late Bronze Age urban

and political system ca. 1200 B.C. is attested in Ugarit and TellTweini (Tweini VIIIB) by military action events (Sea Peopleinvasions) with large fire destruction (16, 19). The abandonmentof Gibala-Tell Tweini has been recorded during part of Iron AgeI. Ugarit was not rebuilt during Iron Age I and II, whereas Gibalaflourished with large urban structures during Iron I, II and III(Tweini VII–V). Architectural and urban patterns changeddrastically between the Iron Age I and II, ca. 900 B.C. (19).During this ACC, the nearby coastal cities reacted differentlyagain, as was the case in the previous ACC. This was probablybecause of local circumstances. Water shortages were eventuallyless severe or nonexistent at Tell Tweini/Gibala, which is builtnear abundant springs.

At ca. 800 B.C., a strong increase of WAMX PdB-scores, anegative deviation in PCA-Axis 1 scores, the recovery of trees,and the higher IoF values all point to a return of wetter climaticconditions during �200 years. This wetter phase is similar to theprevious 1450 to 1175 B.C. humid episode. The ca. 800 B.C. shifttoward humidity marks the end of the global 3.5 to 2.5 cal kyr BPACC in northwest Syria. In the top of the Jableh sequence, a dryspell is registered with an estimated age of 600 B.C.

Climate. Several causes have been invoked to explain the post-6000 calendar year BP ACCs, among which solar forcing appearsto be a plausible one (7, 27, 38). Solar influence on climatically-controlled development of desert-steppe environments in theJableh plain during the 2150 to 500 B.C. interval was tested by

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Fig. 3. Cross-correlograms: WAMX � XERO PdB-scores versus atmospheric �14C (32) and WAST � HODE PdB-scores versus anthropogenic indicators. Verticalaxes show correlation coefficients. Significance level P � 0.05.

13944 � www.pnas.org�cgi�doi�10.1073�pnas.0803533105 Kaniewski et al.

a cross-correlation analysis between the �14C solar proxy andPdBs classified as woods-forest (see Fig. 3). Correlation resultsshow a significant positive correlation (P � 0.05) in the timewindow between increases in atmospheric �14C values indicativeof lower solar irradiance and PdBs classified as woods-forest.These results would confirm the role of solar variability as adriving force of ACCs, although physical mechanisms linkingsolar and climate changes remain unclear (7, 12). The time-interval covered by the TW-1 pollen sequence is not sufficientlylong to derive firm links between solar forcing and vegetationchanges, but the Tweini data strongly suggest that solar vari-ability is a main cause behind middle to late Holocene precip-itation changes over the Near East.

Droughts in the eastern Mediterranean were also associatedwith cooling periods in the North Atlantic for the past 55 kyr(39). The impact of the North Atlantic oscillation on the modernMiddle Eastern climate has been demonstrated (40), emphasiz-ing the potential role of the North Atlantic variability to explainthe Holocene climate changes in the Middle East. The corre-spondence between the arid stages 1 and 3 at coastal Syria andthe Bond events 3 and 2 identified in North Atlantic coreMC52-V29–191 by the bimodal increase of ice rafted hematitestained grains (HSG) (38) (see Fig. 2), shows that Holocene coldevents in the Atlantic Ocean have different climatic signatures.The dry/wet oscillation of the 1175 to 800 B.C. ACC deducedfrom biome changes is well correlated with the second peak ofHSG (Bond event 2) at 900 B.C., whereas a much weakercorrelation is observed for the �4.2 to 3.9 cal kyr BP ACC withBond event 3.

ConclusionThe TW-1 core data demonstrate that for two successive ACCs,climate plays the major role in the composition and distributionof biomes in coastal Syria. During the 4.2 to 3.9 cal kyr BP ACC,PdBs classified as woods-shrubs developed, resulting in shrubbyand thorny vegetation types. The potential role of this ACC onthe cultural development in the Middle East has been abun-dantly documented (5, 9, 11, 12, 29). During the 1175 to 800 B.C.ACC, the development of steppe/desert conditions progressivelytransformed the coastal lowlands into a hot desert biomeculminating at 900 B.C. Also during this ACC, human occupa-tion and cultural development changed dramatically. The TellTweini pollen sequence has demonstrated that abrupt climaticchanges toward aridity as a surrogate for water and foodshortages are a fundamental trigger behind social, political,and economic decision-making of ancient societies during themiddle-to-late Holocene in the Middle East.

MethodsCore, AMS 14C, and Chronology. An 800-cm continuous core (TW-1:35°22�22.94�� N, 35°56�12.49�� E, 17 m asl) was retrieved from the alluvialdeposits of the Rumailiah river, 1.75 km from the coast near Jableh, andanalyzed to document the vegetation dynamics from ca. 2150 to 550 B.C.in coastal Syria. All deposits were sampled with a ramguts corer (length:

100 cm; Ø: 7.5 cm). AMS 14C age determinations (Table 1), based on charredplant macroremains, were obtained for four levels. All 14C ages are pro-cessed after standard pretreatment acid-alkaline-acid, quoted in conven-tional 14C year corrected by normalizing �13C values and calibrated by thecalibration dataset Calib Rev 5.0.1 (41). The age determinations are ex-pressed in B.C. using the year 1950 as time-reference. The chronologycalculated for the upper part of the sequence is confirmed by the presenceof Iron Age ceramics at different depths. Two statistically identical AMSdates, situated near the bottom of the sequence (at 785-cm and 755-cmdepth, see Table 1), within the 2� age range 2200 to 1950 B.C. (mean ageof the two AMS age determinations: 3695 � 28 BP, 2� age ranges 2145–2015 B.C.), suggest a high sedimentation rate during that time. Threesamples are situated within the 2� age range 2145 to 2015 B.C. In thecalculations, these samples are tentatively placed at 2130, 2090, and 2040B.C. The age of the 800-cm sample has been computed at ca. 2150 B.C.

Pollen Grains, PFTs, and Pollen-Derived Biomes. A total of 62 samples wereprepared for pollen analysis using the standard palynological procedure.Pollen data have been converted into PFTs (20, 21) and a pollen-derivedbiomization of the PFTs has been elaborated following the detailed publishedmethods (20, 21). The notation used is similar to the regional studies in theMediterranean and Kazakhstan (21) with WAST, HODE, XERO, and WAMX.

Different indices have been calculated for each sample: (i) A semiquanti-tative IoF index, using the PFTs by dividing (grass � sedge) by (steppe forb/shrub � warm desert forb/shrub � steppe/desert forb/shrub) to evaluatepotential increases in soil moisture. (ii) A semiquantitative Iwa index, calcu-lated by dividing evergreen-deciduous Quercus by steppe markers (Chenopo-diaceae � Ephedra). This Iwa-index strengthens the IoF-index. (iii) An salinity/aridity-index by dividing (Chenopodiaceae � Ephedra) by Artemisia. (iv) Thetaxon richness of terrestrial pollen and spores provides a measure of terrestrialplant diversity through time. (v) The ratios of arboreal and nonarboreal pollenprovide an estimate of the relative forest density.

The regional scale fire history is based on the number of charcoal particleson pollen slides (� 150 �m) and that on larger charcoal remains counted from�100-g samples.

Numerical Analyses. Principal components analysis was computed to test theordination of samples and stages by assessing the major changes in thePdB-scores. The PCA-Axis 1 scores have been added in the pollen-derivedbiomes diagram to determine the main changes according to the linearage-scale.

Linear detrended cross-correlation concerns the time alignment of twotime series by means of the correlation coefficient. For the Jableh data, PdBshave been cross-correlated with atmospheric �14C (41) to find the maximalmatch in age and the potential delay between two events (� insolationversus � trees and shrubs). Steppe-desert PdBs have also been cross-correlatedwith the eastern Mediterranean primary anthropogenic indicators (Fraxinusornus L., Juglans regia L., Olea europaea, Vitis vinifera L., Poaceae cerealia) tomake the distinction between a climatic and an anthropogenic impact on theobserved processes. An average sample interval of 25 years has been fixed forthe whole sequence (2150–500 B.C.) to determine the lag effect betweenclimatic changes, anthropogenic impact, and PdB responses. A total of � 8samples, corresponding with a time window of �200 years, have beenselected as time reference.

ACKNOWLEDGMENTS. This research is funded by the Fonds voor Wetenschap-pelijk Onderzoek, the Onderzoeksfonds Katholieke Universiteit Leuven, andthe Interuniversity Attraction Poles Program VI/34, Belgian Science Policy,Belgium.

Table 1. AMS 14C calibrated ages (2� and 1� ) for core TW-1

SampleDepth,

cmLaboratory

codes Material�13C,

‰ PdB

Conventional14C age

(years BP � 1�)cal (2�) age range

rounded (B.C.)cal (1�) age range

rounded (B.C.)Interception with thecalibration curve (32)

TWE04 EP35 395 Beta-229047 charcoal �22.7 2750 � 40BP 1000–810 920–840 900 B.C.TWE04 EP57 680 Beta-229048 charcoal �26.9 2970 � 40BP 1310–1050 1270–1120 1210 B.C.TWE04 EP73 755 Beta-229049 charcoal �27.3 3710 � 40BP 2200–2000 2150–2030 2060 B.C. and 2080*

B.C. and 2130 B.C.TWE04 EP75 785 Beta-233430 charcoal �26.3 3680 � 40BP 2150–1950 2130–2020 2040 BC and 2100*

BC and 2110 BC

Asterisks indicate the most probable dates.

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