Vott_Geomorphologie_2007

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Gomorphologie : relief,processus, environnementNumro 1/2007 (2007)

Varia

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Andreas Vtt

Silting up Oiniadais harbours(Acheloos River delta, NW Greece).Geoarchaeological implications of lateHolocene landscape changes

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Rfrence lectroniqueAndreas Vtt, Silting up Oiniadais harbours (Acheloos River delta, NW Greece). Geoarchaeological implications oflate Holocene landscape changes , Gomorphologie : relief, processus, environnement[En ligne], 1/2007 | 2007,mis en ligne le 01 avril 2009. URL : http://geomorphologie.revues.org/index645.htmlDOI : en cours d'attribution

diteur : Groupe franais de gomorphologiehttp://geomorphologie.revues.orghttp://www.revues.org

Document accessible en ligne sur : http://geomorphologie.revues.org/index645.htmlCe document est le fac-simil de l'dition papier. Groupe franais de gomorphologie


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Gomorphologie : relief, processus, environnement, 2007, n1, p. 19-36

Silting up Oiniadais harbours (Acheloos River delta,

NW Greece). Geoarchaeological implicationsof late Holocene landscape changes

Colmatage des ports dOiniadai (delta de lAcheloos,

Grce du Nord-Ouest). Impacts goarchologiques

de la mobilit des rivages

Andreas Vtt*

* Faculty of Geography, Philipps-Universitt Marburg, Deutschhausstr., 10, D 35032 Marburg/Lahn, Germany. E-mail: [email protected]

Abstract

Ancient Oiniadai lies on top of the Trikardo hills in the centre of the Acheloos River delta (NW Greece) at a distance of 9 km from the

present coast. Its shipsheds testify to a former connection with the Ionian Sea. This paper focuses on the harbours of the former island

and their palaeoenvironmental changes during the past millennia. Sedimentological, geochemical, micro- and macrofaunal and paly-

nological analyses of sediment samples from 15 vibracores as well as detailed earth resistivity tomography were carried out. A

geochronology of environmental changes was established using 23 14C AMS dates and relative age determinations of ceramic frag-

ments. Based on sedimentary and archaeological evidence, it was found that around 3000 cal yr BC, during early Helladic times, a

harbour existed on the swampy lagoonal shore in the southeast. High river water inflow into the northern embayment and the necrop-

olis bay started at 13001000 cal yr BC, during Mycenaean times, resulting in a decrease of the siltation of the lagoon rates and inducing

ideal anchoring conditions. During Classical-Hellenistic to Roman times when the shipsheds were in use the northern harbour expe-

rienced ongoing water inflow from the Acheloos River and communicated with the sea via a lagoon. The necropolis bay was also a

favourable harbour site. During Roman to Byzantine times, a river harbour existed near a palaeo-Acheloos meander flowing by thesoutheastern fringe of Trikardo. No sedimentary evidence was found that the island ever had a harbour at the seafront. Trikardo,

throughout the millennia, represented an excellent terrestrial outpost amidst a low lying coastal zone, well protected by the almost

impenetrable lagoonal and marshy grounds and, at the same time, providing rapid access to the sea.

Keywords: ancient harbour, palaeoenvironmental changes, late Holocene, Oiniadai, Acheloos River delta, Greece

RsumLancienne cit dOiniadai se localise au sommet des collines de Trikardo au cur du delta de lAcheloos au nord-ouest de la Grce(Bousquet, 1976). Ce site est de nos jours loign de neuf kilomtres du rivage actuel, alors que la prsence de cales de halage, datesentre le cinquime et le troisime sicle avant Jsus-Christ tmoignent dune relation avec la mer Ionienne durant lAntiquit (Phi-lippson, 1958 ; Villas, 1984 ; Bousquetet al., 1987 ; Kolonas, 1992 ; Fouache et al., 2005 ; Vttet al., 2004). Cet article analyse la

localisation successive des ports antiques de cette ancienne le ainsi que les principaux changements environnementaux qui ont affec-t le delta de lAcheloos depuis environ 6 000 ans. Les chantillons de quinze carottages ont t analyss du point de vuesdimentologique, gochimique, faunistique, palynologique et go-chronologique (23 datations au radiocarbone et dtermination descramiques). Ces analyses haute rsolution ont aussi t croises avec ltude tomographique du sous-sol. Nos donnes montrent que, partir de 3 000 ans avant Jsus-Christ (priode helladique ancienne), un port tait prsent dans le secteur lagunaire au sud-est delancienne le. Par comparaison, des flux hydriques importants partir de 1 300-1 000 avant Jsus-Christ (priode mycnienne, gedu bronze) ont favoris un ralentissement du colmatage du port nord et de la baie de la ncropole. Cette phase a t la plus favorable ltablissement dun port protg et en eau douce entre 1 000 et 100 avant Jsus-Christ. Durant les priodes classique, hellnistiqueet romaine, quand les cales de halages taient fonctionnelles, le bassin nord communiquait donc avec la mer par lintermdiaire dunelagune. La baie de la ncropole tait aussi un abri ctier favorable. Aux poques romaine et byzantine, un port fluvial tait localis lelong dun mandre de lAcheloos. Dans ltat actuel de nos connaissances, nous navons pas pu dmontrer la prsence dun port mari-


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time le long des rivages de lancienne le de Trikardo. Ce site reprsente ainsi larchtype dun avant-port fluvial au cur dun syst-me deltaque, milieu paralique la fois protg par les lagunes et en relation rapide avec le plan deau marin.

Mots cls : port antique, paloenvironnement, Holocne rcent, Oiniadai, delta de lAcheloos, Grce.

Version franaise abrge

La cit antique dOiniadai se localise au sommet des col-lines de Trikardo au cur du delta de lAcheloos (Grce duNord-Ouest), neuf kilomtres du rivage actuel. Ses calesde halage tmoignent que, durant lantiquit, il y avait uneconnexion entre Oiniadia et la mer ionienne (fig. 1). Lvo-lution gomorphologique du delta de lAcheloos depuis8 000 ans est maintenant bien connue grce aux travaux deVttet al. (2004, 2007a, 2007b) et Vtt et Brckner (2006).Cet article prsente des donnes indites sur la localisationdes anciens ports et la mobilit des rivages depuis lAnti-

quit. Les chantillons ont t extraits de quinze carottages.Des analyses gochimiques, micro et macrofaunistiques et palynologiques permettent de caractriser les principauxfacis sdimentologiques. Une tude de rsistivit lectriquedu sous-sol a t effectue afin de prciser la gomtrie descorps sdimentaires. La chronologie a t obtenue par data-tion radiocarbone (23 datations AMS, tableau 1) et par lesinformations tires de ltude de la cramique.

Cinq profils de carottages ont t effectus. Le profil I (ca-rottages OIN 47, 48 et 54) traverse le port nord (fig. 1 et 2).Les rsultats montrent que le milieu de sdimentation corres-pond une lagune depuis 4 400 ans avant J.-C (chantillonOIN 47/18 M2 : 4433-4315 cal BC ; tableau 1). Ds lge dubronze, ce lagon permettait donc une communication entre leport nord et la mer. Le lagon a ensuite t dconnect du do-maine marin par des apports fluviaux importants (fig. 3 etVttet al., 2007a). Des indices gochimiques de faible sali-nit et des pollens dAbies sp. tmoignent dapports deaudouce importants par lAcheloos entre 1 000 et 100 ans avantJ.-C. (chantillons OIN 47/14+ M : 1151-1007 cal BC et OIN47/11 PR : 171-2 cal BC ; fig. 3 et 4, tableau 1).

Le profil II (carottages OIN 41, 49 et 63) prsente lesmilieux de sdimentation de la baie sud de Trikardo (fig. 1et 2). La zone interne de la baie sindividualise par desfacis limniques et des accumulations de tourbe, alors que

la zone externe est caractrise par des dpts marins deltage infralittoral suprieur (fig. 5 et 6). Cette baie sud nadonc jamais pu servir de port (cf. Murray, 1982 : 43ff.).

Les profils III (carottages OIN 44, 64, 65 et 69) et IV(carottages OIN 66, 67 et 68) se localisent au sud-est de Tri-kardo (fig. 1 et 2). Ils mettent en vidence des fonds rocheux jusque vers 3 000 ans avant J.-C. (chantillons OIN44/20+ PR : 3088-2926 cal BC et OIN 69/13 ST/M/BE :3060-2915 cal BC ; fig. 7a, 7b, 8 et 11, tableau 1). Ensuite,un bras de lAcheloos est lorigine dun dveloppementdune lagune et localement de marcages (fig. 6 et 7a). La prsence de nombreux fragments dHexaplex trunculus

tmoigne de lutilisation de ce littoral par des pcheurs lapriode helladique ancienne (chantillons OIN 44/20+ PR :3088-2926 cal BC et OIN 44/17 PR : 2902-2713 cal BC ;

fig. 7a, tableau 1). Bas sur la comparaison des dpts lagu-naires trouvs en OIN 70 avec lvolution Holocne duniveau de la mer relatif autour de Trikardo (Vtt, 2007), lalagune, fortement influence par les apports deau douce delAcheloos, va cependant perdurer jusque vers 250 ans aprsJ.-C. (fig. 7b). En OIN 64 et 65, nous avons retrouv des frag-ments de cramique romaine et byzantine dans un facisdaccumulation dun mandre proche de lAcheloos.

Le profil V (carottages OIN 10 et 70) se localise proxi-mit de la baie de la ncropole (fig. 1 et 2). La carotte OIN10 traduit des apports sableux dorigine fluviale (fig. 9, 10a,10b et 11). La carotte OIN 70 met en vidence la prsence

dune lagune, sous influence fluviale, partir de 1 300 ansavant J.-C. (chantillon OIN 70/10+ PR : 1419-1314 calBC ; fig. 9, tableau 1). De ce fait, la baie de la ncropoleest un milieu attractif pour abriter un bassin portuaire, auxqualits proches du port nord.

Nous dmontrons que la communication entre les cales dehalage du port nord et la mer est complexe. Elle ne se faisaitpas uniquement par lintermdiaire dun bras fluvial, commelavaient suggr Leake (1835, vol. III : 564ff.), Sears (1904 :227, 235), Heuzey (1860 : 447f.) et Lolling (1876/77 : 282).De mme, aucun indice bio-sdimentologique ne permet deconclure que le port nord se localisait en front de mer commelont publi Lehmann-Hartleben (1923 : 80) et Fouache et al.(2005). Les auteurs anciens avaient dailleurs dj notquOiniadia pouvait tre atteint par le fleuve Acheloos (Poly-be 4, 65, 2-9) et que lembouchure fluviale se localisait trei-ze kilomtres de la cit (Strabon 10, 2, 21).

Enfin, un nouveau port, attribu la priode helladiqueancienne, a t mis en vidence au sud-est dOiniadia dansun environnement lagunaire. Ce site a pu tre utilis auxpoques classique, hellnistique et romaine. partir de lafin de lpoque romaine et la priode byzantine, un port fluvial se localisait dans ce secteur. Trikardo a reprsentdurant des sicles un abri ctier exceptionnel, la fois bienprotg par un environnement lagunaire difficilement pn-

trable et en relation rapide avec la mer pour ses habitants.

Introduction

Deceleration of sea level rise during the mid-Holocenearound 60004000 BC initiated delta formation all over theworld (Stanley and Warne, 1994). Since that time, riverdeltas which represent terrestrial outposts in a marineenvironment have always been appreciated by man forfishing and settlement activities. However, continuous deltaprogradation and coastal changes have implied a steadystruggle against siltation in order to guarantee open access

to the sea.In the deltaic areas of the eastern Mediterranean, numer-ous archaeological sites testify to considerable environmen-

20 Gomorphologie : relief, processus, environnement, 2007, n1, p. 19-36

Andreas Vtt


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tal changes during the late Holocene and thus have been sub-ject to intense geoarchaeological investigations. Most of thestudies are based on the analyses of sediments from near-coastal geological archives. Besonen et al. (2003), for exam-ple, reconstructed strandline displacement of 5 km by theprograding Acheron River since 400 BC. At that time, an-

cient Ephyra and the nearby Nekromanteion, oracle of thedead, still lay on the marine front. Kraft et al. (1987) showedhow delta progradation of the Sperchios River changed thenarrow coastal pass at Thermopylae, where the Greek armyunder Leonidas fought their famous battle against the Persianarmy in 480 BC, into the wide alluvial plain of present times.The Aliakmonas, Loudias, Axios and Gallikos River deltasare responsible for the rapid siltation of the Thermaikos Gulf(Vouvalidis et al., 2005). Nearby Pella, the hometown ofAlexander the Great, had already lost direct access to the gulfaround 1 BC/AD (Vtt and Brckner, 2006). Around ancientTroy, the wide marine embayment from the time of the so-

called Trojan War around 1200 BC was silted up by theDmrek (Simois) and Karamenderes (Scamander) Rivers(Kraft et al., 2003). Further south,the prograding Kk Menderes(Kaystos) River had caused infillingof the Holy Harbour of Ephesus byRoman times (Brckner, 2005).Neighbouring seaports such asPriene, Myous, and Miletus weresealed off from open marine condi-tions by the prograding BykMenderes River around 300 cal BC(Mllenhoff, 2005; Brckner et al.,2006). These examples show thatriver deltas are good archives for re-constructing the complex interac-tions between sea level rise, sedi-ment supply, and coastline displace-ment as well as for detecting inter-actions between man and the envi-ronment.

During the past millennia, the pro-grading Acheloos River (Akarnania,NW Greece) has landlocked severalislands of the former Echinades

archipelago (Philippson, 1958; Vil-las, 1984; Bousquet et al., 1987;Fouache et al., 1998; Fouache,1999; Vtt et al., 2004, 2007a,2007b; Vtt and Brckner, 2006).Today, ancient Oiniadai with itsfamous shipsheds from the 5th to3rd centuries BC is located some9 km inland (fig. 1). This paperfocuses on the former ports of theisland. The main objectives were (i)to reconstruct palaeoenvironmental

changes in the northern harbour, (ii)to clarify whether other ports exist-ed, (iii) to find out how and when

the harbours lost their function, and (iv) to document how thesiltation of ancient harbours was controlled by the prograda-tion of the Acheloos River delta.

Geomorphological setting andhistorical background

The Acheloos River delta plain encloses several formerislands of the Echinades archipelago (fig. 1). The rocky hillsare made up of Triassic limestone, limestone breccia,dolomite and locally gypsum, and are thus strongly karsti-fied (Bousquet, 1976; IGME, 1989). In general, they arebound to SSW-NNE and SE-NW-striking local tectonicfault systems that are connected to the nearby Amfilochiafault zone, an active rift running between the gulfs ofAmbrakia and Patras and separating the Akarnanian massfrom the central Greek mainland (Haslinger et al., 1999).Most parts of the delta are characterized by local subsidence

(Vtt, 2007). Ancient Oiniadai lies on top of the formerTrikardo island (99 m a.s.l.) in the centre of the delta.

21Gomorphologie : relief, processus, environnement, 2007, n1, p. 19-36

Silting up Oiniadais harbours (NW Greece)

Fig. 1 The central Acheloos River delta, NW Greece, and the former island of Trikardo

bearing the archaeological remains of ancient Oiniadai. Topographic overview and

locations of the different former harbours and embayments investigated within this study.

1: modern village; 2: ancient site; 3: main road; 4: vibracoring site (OIN); 5: karstic spring; 6:

periodically running creek (rema); 7: paleo river channel (oxbow); 8: Holocene Acheloos alluvial

plain; 9: Triassic bedrock (limestone, dolomite).

Fig. 1 Le delta de lAcheloos (Grce du NW) et lancienne le de Trikardo o sont situs

les restes de lancienne cit dOiniadai. Esquisse topographique et localisation des

anciens ports et baies successifs. 1 : village actuel ; 2 : site antique ; 3 : route principale ; 4 :

site de prlvement de carotte ; 5 : source karstique ; 6 : ruisseau intermittent ; 7 : ancien chenalfluviatile (mandre) ; 8 : plaine alluviale holocne de lAcheloos ; 9 : substratum rocheux du Trias

(calcaire, dolomie).


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Historically, Oiniadai was ofgreat strategic importance as itis located at the entrance to thegulfs of Patras and Corinth.The Akarnanian islet was at-tacked repeatedly between 454 BC and the 3rd century BCby Greek powers. In 252 BC, it came under Aetolian rule(Oberhummer, 1887: 83, 101; Powell, 1904: 139; Freitag,1994: 223). The Macedonian king Philip V conquered thecity in 219 BC, renovated the shipsheds, fortified the citywalls and gave Oiniadai back to the Akarnanians. In212 BC, Trikardo was captured by the Romans and, a fewyears later, in 189 BC, reintegrated into the AkarnanianLeague. Then, historical traces quickly fade and the sitesank into insignificance. In 167 BC, all Akarnania becamepart of the Roman Republic (Powell, 1904: 144).

Materials and methods

Lateral and vertical variations of sedimentary facies ingeological archives were determined in order to reconstructpalaeoenvironmental conditions and their changes in time

and space. In the Acheloos River delta, 70 sediment coreswere retrieved by means of an Atlas Copco vibracoringdevice (Cobra mk1) with core diameters of 6 or 5 cm. Forthis paper, 15 vibracores drilled in the vicinity of Oiniadaiwere analyzed, arranged in five transects. The maximumrecovery depth of the vibracores was 15 m below surface(m b.s.). In the field, the sedimentary environment wasclassified based on sedimentological criteria and macrofos-sil remains, such as gastropods, bivalves, seeds, or plantfragments. Sampling of vibracore profiles allowed fordetailed micro- and macrofaunal studies as well as for geo-chemical analyses of parameters such as electrical

conductivity, pH-value, loss on ignition, carbonate contentand concentrations of (ortho-)phosphate, (earth-)alkalineand heavy metal ions measured in a chemical pulping on the

basis of concentrated hydrochloric acid. Facies determina-tion was mainly based on ostracod species and assemblagesbecause these are reliable ecological indicators (Frenzel andBoomer, 2004). Vertical profiles of geochemical parametersand multivariate discriminant analyses of geochemicaldatasets were also valuable tools for controlling and deter-mining sedimentary facies (Vtt et al., 2003). Macrofloralremains and pollen found in sediment samples gave addition-al information about the palaeoenvironment. A differentialGPS (Leica SR 530) was used to determine the position andelevation of vibracoring sites. Earth resistivity tomography(Syscal R1 plus, Iris instruments) helped to detect subsur-faces structures and the distribution pattern of sedimentarysequences. Twenty-three 14C-AMS dates and relative agedeterminations of diagnostic ceramic fragments were used toestablish a geochronological framework. The reservoir effectfor radiocarbon-dated marine samples was corrected for an

average of 402 years (Reimer and McCormac, 2002). Allradiocarbon ages given in the paper were calibrated (calBC/AD) using the calibration software Calib by Stuiver et al.(2006). Corona satellite photos (USGS, 1965), Landsat7 ETM+ and Aster (2001) images helped to reconstructpalaeogeographical changes.

Geological archives revealing thedestiny of Oiniadais harbours

The northern harbour and the shipsheds

Oiniadais northern harbour (figs. 1 and 2) is made up ofan outer and an inner harbour section. The shipsheds lie atthe eastern side of the outer embayment, which is almost


Andreas Vtt

Fig. 2 Detailed map of Trikardo

island and selected archaeologi-

cal remains of ancient Oiniadai.

Locations of vibracoring sites and

transects of earth resistivity tomo-

graphy in the vicinity of the former

island. Map based on Corona

satellite photo (USGS, 1965) andarchaeological data from Powell

(1904), Kirsten (1937), and Kolo-

nas (1992).

Fig. 2 Carte dtaille de lle de

Trikardo et principaux vestiges

archologiques de la cit antique

dOiniadai. Localisation des diff-

rentes carottes et transects tomo-

graphiques proximit de lancien-

ne le. Carte tablie daprs limage

satellitale (USGS, 1965) et les don-

nes archologiques tires de Po-

well (1904), Kirsten (1937) and Ko-

lonas (1992).


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250 m wide. Five slipways were used for repairing triremes,ancient Greek warships, and for storing them during winterseason (Kolonas, 1992). The inner harbour, only 80-120 mwide, is located southeast of the dockyard in a narrow inden-tation. In antiquity, it could be closed by a chain (Murray,1982: 42). Transect I covers both the inner (OIN 48) and

outer harbours (OIN 54). OIN 47 was drilled in front of theshipsheds.

The facies distribution pattern shows that at OIN 54 andOIN 47, open marine conditions prevailed until circa4400 cal BC (sample OIN 47/18 M2: 4433-4315 cal BC;fig. 3, table 1). Around that time, an Acheloos River dis-tributary approached from the north and sealed off a largelagoon north of Trikardo. OIN 48 was never affected byopen marine waters but, later, by the transgressive lagoonalunit overlying alluvial-fan palaeosol sediments. The lagoon-al sediments, which were encountered at OIN 47, 48 and 54,

were of an olive-green colour and showed abundant shellsand shell fragments of a macrofaunal assemblage character-istic of shallow marine to brackish conditions (such asCarcinus sp., Cerastoderma glaucum, Cerithium rupestre,Cyclope neritea, Dosinia exoleta, Gibbula sp.). High con-tent of organic material, up to almost 10%, indicates almost

swampy conditions. Between 5 m and 4 m below present sealevel (m b.s.l.), sedimentary conditions at OIN 47 and 48were abruptly affected by strong freshwater input as shown,for instance, by a decrease in electrical conductivity of thesediment (fig. 4a) and by a change towards a (light) greycolour. The occurrence of fine sand indicates mid- to high-energy influence on the quiescent conditions, which untilthen were typical of the harbour basin. At the same time,pollen ofAbies sp. increased to maximum concentrations.This proves a direct influence of Acheloos River water(Jahns, 2005, pers. comm.) as (i) the tree only exists in high



Sample Name Depth(m b.s.)

Depth(m b.s.l.)

Sample Description Lab. No. 13C(ppm)

14C Age(BP)

1 max; min(cal BP)

1 max; min(cal BC)

OIN 10/19 M 7.80 5.62 D. exoleta, articulated specimen UtC12320 1.7 5032 48 5432 - 5322 3482 - 3372*

OIN 41/14+ M 3.46 2.20 D. exoleta, articulated specimen UtC 13696 1.6 2203 34 1856 - 1754 94 - 196 AD*

OIN 44/17 PR 6.90 4.10 peat, organic material UtC 13701 -28.3 4232 42 4852; 4663 2902; 2713

OIN 44/20+ PR 7.63 4.83 peat, organic material UtC 13700 -28.9 4399 40 5038; 4876 3088; 2926

OIN 44/28 PR 11.36 8.56 wood fragment UtC 13699 -27.7 6393 39 7415; 7272 5465; 5322

OIN 47/11 PR 3.74 3.19 unidentified plant remains UtC 13704 -9.9 2070 60 2121; 1952 171; 2

OIN 47/14+ M 4.73 4.18 Paphiasp., articulated specimen UtC 13703 0.4 3219 41 3101 - 2957 1151 - 1007*

OIN 47/18 M2 6.70 6.15 D. exoleta, articulated specimen UtC 13702 -1.2 5900 60 6383 - 6265 4433 - 4315*

OIN 49/7+ PR 2.58 1.95 peat, organic material UtC 13709 -28.5 570 38 633; 537 1317; 1413 AD



OIN 49/19+ GPRA 6.68 6.05 peat, organic material UtC 13706 -27.5 5730 50 6616; 6451 4666; 4501


OIN 54/12+ PR 6.29 5.22 seeds from Iris pseudoacorus UtC 13713 -7.9 2377 45 2461 - 2344 511 - 394

OIN 63/10 PR 3.85 2.62 unidentified plant remains Erl 9055 -10.9 2674 43 2842; 2749 893; 800

OIN 63/14 P 5.64 4.41 sea weed remains Erl 9056 -16.1 2894 43 2734; 2610 785; 661*

OIN 63/15+ PR 6.57 5.34 peat, organic material Erl 9057 -28.2 5144 50 5985; 5761 4036; 3812

OIN 65/14 M2 5.34 2.45 P. conica, C. rupestre, several spec. Erl 9058 1.6 3379 48 3324 - 3196 1375 - 1247*

OIN 69/13 ST/M/BE 5.61 2.92 rock-boring mussel, articulated spec. Erl 9059 -2.2 4717 48 5009 - 4864 3060 - 2915*

OIN 69/14 HR 5.90 3.21 unidentified plant remains Erl 9060 -26.2 4209 41 4841; 4651 2892; 2702

OIN 70/8+ M 4.63 2.82 B. latreilli, articulated specimen Erl 9061 -4.3 3365 46 3312 - 3179 1363 - 1230*

OIN 70/10+ PR 6.14 4.33 unidentified plant remains Erl 9062 -10.8 3094 43 3368; 3263 1419; 1314

OIN 70/15 M 7.76 5.95 D. exoleta, articulated specimen Erl 9063 -0.4 5753 57 6255 - 6113 4306 - 4164*

Table 1 Radiocarbon dating results for samples from vibracores around Trikardo, central Acheloos River delta. b.s.: below ground

surface; b.s.l.: below sea level; B. latreilli: Bittium latreilli; C. rupestre: Cerithium rupestre; D. exoleta: Dosinia exoleta;P. conica: Pirenella

conica; spec.: specimen(s); *: marine reservoir correction with 402 years of reservoir age; 1 max; min cal BP/BC (AD): calibrated ages, 1-

range; ;: there are several possible age intervals because of multiple intersections with the calibration curve; Lab. No.: laboratory number;

University of Utrecht (UtC), University of Erlangen-Nrnberg (Erl).

Tableau 1 Datations radiocarbone des carottes du secteur de Trikardo, centre du delta de lAcheloos. b. s. : sous la surface du sol ;

b. s. l. : sous le niveau de la mer ; B. latreilli : Bittium latreilli ; C. rupestre : Cerithium rupestre ; D. exoleta : Dosinia exoleta ; P. conica : Pirenella

conica ; spec. : specimen(s) ; * : correction des calibrations pour un ge rservoir de 402 ans ; 1 max; min cal BP/BC (AD) : datationscalibres, 1-range; ; : il peut y avoir plusieurs intervalles dge possibles du fait dintersections multiples avec la courbe de calibration ;

Lab. No. : rfrence de lchantillon, laboratoire de luniversit dUtrecht (UtC) ou de luniversit dErlangen-Nrnberg (Erl).


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mountain ecosystems such as the Pindos mountains in thecatchment area of the Acheloos River, and does not occur insouthern Akarnania itself and (ii) pollen fromAbies sp. is not

transported by wind over long distances. Acheloos riverinflow occurred via a distributary which, around 1000 cal BC,branched off the deltafront east of Trikardo and flowed along

the eastern and northern flank of the island (sample OIN47/14+ M: 11511007 cal BC; fig. 3, see Vtt et al., 2007afor further details). OIN 54 stratigraphy indicates that the

river channel into the harbour was still active in the 4th cen-tury BC (sample OIN 54/12+ PR: 511394 cal BC; fig. 3,table 1). Around 100 cal BC, the lagoonal waters of the har-


Andreas Vtt

erosional unconformity

Sedimentary

faciesNNWSSE

Fig. 3 Distribution pattern of sedimentary facies in Oiniadais northern harbour (transect I). F: fluvial (crevasse splay, flood channel);

H: limnic to fluvial (flood plain or fresh marsh); T: semi-terrestrial (peat, calcareous gyttja); Ss: semi-terrestrial to limnic (swampy lake); SI:

semi-terrestrial to lagoonal (swampy lagoon); R: fluviomarine (river channel); D: fluviomarine (delta); S: limnic (freshwater lake); SF: fluvial to

limnic (riverwater inflow into freshwater lake); L: brackish to brackish-marine (lagoon); LF: limnic to brackish (lagoon with r iver water influen-

ce); P: brackish to shallow marine (prodelta); S/T: brackish to shallow marine (storm layer, tsunami deposit); B : shallow marine, littoral (sand

bar, tombolo, beach); Fe: shallow marine, littoral (rocky and supra littoral zone); FI: shallow marine, sublittoral (marine embayment); F (on

black): early to mid-Holocene alluvial fan (palaeosol); PS: Pleistocene-Holocene palaeosol; BR: bedrock.

Fig. 3 Chronostratigraphie des facis sdimentaires du port nord dOiniadai (transect I). F : fluviatile (dpt de crue) ; H : lacustre

fluviatile (plaine dinondation, marcage) ; T : dpt organo-terrigne (tourbe, gyttja calcaire) ; Ss : organo-terrigne lacustre (lac mar-

cageux) ; SI : dpt de lagune marcageuse ; R : dpt fluvio-marin (chenal fluviatile) ; D : dpt fluvio-marin (delta) ; S : dpt lacustre ;

SF : fluviatile lacustre (dpt dorigine fluviatile dans un lac) ; L : dpt lagunaire ; LF : lacustre saumtre (lagune influence par des

eaux fluviales) ; P: dpt saumtre marin de faible profondeur (prodelta) ; S/T : saumtre marin de faible profondeur (dpt de tem-

pte, de tsunami) ; B : dpt littoral (cordon sableux, tombolo, plage) ; Fe : dpt supralittoral et littoral rocheux ; FI : dpt sublittoral (baie) ;

F (sur fond noir) : palosol sur cne alluvial (Holocene ancien et moyen) ; PS : palosol (Plistocne-Holocne) ; BR : substrat.


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bour turned limnic (sample OIN 47/11 PR: 1712 cal BC;fig. 3, table 1). Until that time, highAbies sp. pollen countsand low salinity of the sediment reflect ongoing Acheloos-borne freshwater inflow (fig. 4a). Groundwater has kept asmall outflow open towards the present-day drainage chan-nel which flows by the harbours entrance and is mostly fed

by high-discharge karstic springs at the foot of the adjacentLesini mountains.

Figure 4 exemplarily depicts geochemical parametersanalysed for sediment samples from vibracores OIN 47, 48and 54 clearly reflecting facies distribution patterns foundfor the northern harbour (fig. 3). Electrical conductivity val-ues found for OIN 47 and 54 show a steep, partly stepwisedecrease towards the top corresponding to the beginning ofstrong freshwater inflow to the outer harbour (fig. 4a). AtOIN 54, sedimentary conditions were considerably influ-enced by karstic springs located in the innermost harbourarea (fig. 2). Minimum contents of (ortho-)phosphate at

OIN 47 and 48 are characteristic of quiescent lagoonal envi-ronments and of phases of increased freshwater input (fig.4b). High CaMg ratios indicate periods of increased supplyof calcium from a marine source (fig. 4c), whereas maxi-mum FeNa ratios stand for increased influence of fluvialand terrestrial processes on the ecosystem (fig. 4d).

Additionally, earth resistivity tomography was carriedout along two transects in the outer harbour (oin-g-10 andoin-g-11, fig. 5). Inverse model resistivity sections showbedrock units below 18 m b.s. They are covered by marinesediments with extremely low resistivity values. Increas-ing resistivity towards the top indicates the change

towards lagoonal and later limnic deposits. Figure 5 alsoillustrates the river channel that entered the harbour fromthe north.

In summary, the northern flank of Trikardo was exposedto a lagoon since around 4400 cal BC when a large Ache-loos distributary, prograding southward, closed the area offfrom open marine conditions. From Mycenaean to earlyRoman times, the harbour bay was connected to the sea viaa lagoon which gradually silted up through the present. Itsremains can still be seen north of Kounovina. Our data pro-vide evidence of freshwater inflow by an Acheloos Riverchannel into the northern harbour between approximately

1000 and 100 cal BC. However, it is still unclear (i) whetherthis river channel was of natural or anthropogenic originand (ii) whether it was used as a waterway to reach the ship-sheds from the east. Around 100 cal BC, the northernharbour turned into a limnic environment and silted up soonafterwards.



Fig. 4 Selected geochemical parameters analysed for sediment samples from vibracores OIN 47, 48 and 54 (transect I). Vertical

profiles of geochemical parameters such as electrical conductivity (a), concentration of (or tho-)phosphate (b) as well as calcium-magnesium

(c) and iron-sodium ratios (d) are useful tools to determine facies distribution patterns (see Vtt et al., 2003).

Fig. 4 Analyse gochimique des chantillons des carottes OIN 47, 48 et 54 (transect I). Lvolution verticale des paramtresgochimiques tels que la conductivit lectrique (a), la concentration en (ortho-)phosphate (b), les rapports calcium-magnsium (c) et fer-

sodium est utile pour dterminer la chronostratigraphie des facis sdimentaires (cf. Vttet al., 2003)


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The southern embayment

The southern embayment, scarcely 200 m long and 100 mwide, is located at the southern flank of Trikardo just oppo-site to the northern harbour and exposed towards the presentcourse of the Acheloos River (figs. 1 and 2). Oiniadais for-tification wall crosses the swampy ground and divides theindentation into two parts. The wall itself has a gap, severalmeters wide, which might be interpreted as the entrance tothe inner section of a port. Transect II runs from the innerpart of the bay (OIN 49), north of the wall, to the (central)outer part of it (OIN 63), south of the wall. OIN 41 wasdrilled at the entrance of the embayment (fig. 2).

Facies distribution patterns prove that OIN 49 underwentan evolution almost completely detached from the outerbay (fig. 6). The profile is made up of peat and lake

deposits. At 4.64 m b.s.l., an intermediate lens of medium

sand, 11 cm thick, as well as fine sand components encoun-tered in the overlying limnic sediments (4.53-3.87 m b.s.l.)reflect a sudden and temporary fluvial impact. In contrast,sedimentary sequences at OIN 41 and 63 start with littoraldeposits. At OIN 63, well sorted medium to coarse sandwith abundant fragments of marine macrofauna such asAcanthocardia sp.,Arca noae, Conus sp., Ostrea sp.,Echi-noidea and corals reflects a beach environment. At OIN 41,silty fine sand with fragments of marine shells and Crus-tacea represents the corresponding (sub-)littoral shorefaceunit. Subsequent laminated prodeltaic deposits found invibracore OIN 41 show that, later, a distributary of the Ach-

eloos River approached the site. Soon afterwards, thedistributary reached the southern embayment, partly erodedan older peat layer at OIN 63 and flushed into the inner sec-


Andreas Vtt

Fig. 5 Simplified inverse model resistivity sections for the northern harbour and the southern embayment based on earth

resistivity measurements. Logs represent simplified facies profiles of vibracores.

Fig. 5 Profils golectriques du port nord dOiniadai et de la baie Sud de Trikardo. Les logs reprsentent les facis simplifis des

carottes.


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tion of the bay as indicated by the sandy intercalationsencountered at OIN 49. Radiocarbon dating of this eventyielded an age of circa 3100 cal BC (sample OIN 49/15+PR: 32612925 cal BC; fig. 6, table 1). Muddy lagoonaldeposits encountered on top of the deltaic sand units outsidethe wall bear signs of freshwater input such as fragments of

a brackish macrofauna, a light sediment colour and highamounts of fine sand of fluvial origin. Strong fluvial influ-ence to the outer section of the bay persisted at least until theend of the 1st millennium BC (fig. 6). The subsequentlagoonal environment existed considerably longer com-pared to the northern harbour. A layer of shell debris,deposited at OIN 41 possibly due to high-energy storm ortsunami wave action, dates to the 2nd century AD (sampleOIN 41/14+ M: 94196 cal AD; fig. 6, table 1). During lateByzantine times, the lagoon was filled up by alluvial sedi-ments (fig. 6).

Earth resistivity measurements along a NS trending tran-

sect (oin-g-12, fig. 5) revealed that in the midst of the gap inthe wall, immediately south of OIN 49, high resistivity val-ues reach up to 3.75 m b.s. (about 3.10 m b.s.l.) and arebound to almost rectangular contours. It is concluded thatthe wall was originally erected on top of the bedrock. Later,when the fortification system was out of use, it was partlytorn down. Even if the uprising structure was made out ofbedrock, the inner section could never have been used as aharbour because the relative sea level was at approximately3.25-3.10 m b.s.l. during Classical-Hellenistic times (Vttand Brckner, 2006; Vtt et al., 2007a; Vtt, 2007), i.e. atthe upper edge of the low resistivity structure. Figure 5 alsoshows that the fluviodeltaic and fluviolagoonal sequences

found at OIN 63 correspond to a river bend which tangen-tially flowed into the outer section of the bay.

The swamp around OIN 49 is fed by karstic springs northof the vibracoring site (fig. 2). Not far to the northwest of theindentation, a sinkhole, 60 m wide and approximately 20 mdeep documents strong karstification. The inner section of

the southern bay may therefore correspond to a kettle-likekarstic hollow incorporated into the fortification system toensure freshwater supply for the city or simply to shortenthe length of the wall.

The southeastern harbour

Seven vibracorings were carried out around a circular-shaped bedrock outcrop lying around 250 m east of thesoutheastern fringe of Trikardo (fig. 1). Transect III runsfrom north to south (OIN 44, 64, 65 and 69), and transect IV(OIN 66, 67 and 68) from east to west (figs. 2, 7a, 7b and 8).

The base of OIN 44 shows lagoonal sediments which con-sist of silty clay and include abundant fragments of a brack-ish macrofauna. The sediments were accumulated in a shal-low-marine to brackish environment on top of the bedrock.The lagoonal transgression dates to the 6th millennium BC(sample OIN 44/28 PR: 54655322 cal BC; fig. 7a, table 1).A subsequent peat layer (4.874.00 m b.s.l.) contained sev-eral ceramic fragments which were dated to late Helladic oreven earlier times (Lang, 2005, pers. comm.). The pit of a fig(4.33 m b.s.l.) and a piece of bone, 5 cm long (4.10 m b.s.l.),as well as abundant fragments ofHexaplex trunculus, up to5 cm large, were also found within the peat unit. Obviously,the swampy site was used as waste dump and, at the same

time, lay close to a wharf used by fish-ermen. Like Bolinus brandaris,Hexaplex trunculus , an edible species,was used to produce dye for colouringtextiles. The species is well adapted topolluted harbour areas (Poppe andGoto, 1991: 136). Two 14C-AMSdates from the lower (4.83 m b.s.l.)and the upper (4.10 m b.s.l.) part ofthe peat layer yielded ages of30882926 cal BC (sample OIN44/20+ PR) and 2902-2713 cal BC

(sample OIN 44/17 PR; fig. 7a,table 1), respectively. These resultsprove an early Helladic age of the ce-ramic fragments. OIN 44 thus re-vealed, for the first time, early BronzeAge colonization of Trikardo. Theupper part of the peat unit and the



Fig. 6 Distribution pattern of sedimen-

tary facies in the southern embayment

of Trikardo (transect II).

Fig. 6 Chronostratigraphie des facissdimentaires de la baie mridionale de

Trikardo (transect II).


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subsequent lagoonal deposits contained several stones, up to6 cm large, which seem to be filled in by man in response torising sea level. Upward increasing contents of fine sand in-dicate strong fluvial input to the brackish water body, beforeit was silted up by alluvial sediments. This is confirmed bythe distribution pattern of electrical conductivity values ofsediment samples taken from vibracore OIN 44. Electrical

conductivity decreases abruptly from 1.5-2.5 mS/cm forsamples between 6 and 4 m b.s.l. from lagoonal environ-ments to values around 0.5 mS/cm for samples taken above

4 m b.s.l., which were strongly af-fected by fluvial influence.

The base of OIN 65 shows a rocky(supra-)littoral facies, followed bylagoonal and then limnic depositsboth of which were influenced by

river water inflow (fig. 7a). Thelimnic sediments are covered bymarsh deposits and a subsequentpalaeosol both of which containednumerous ceramic fragments. How-ever, most of the potsherds wereweathered and could not be used forage determination. At OIN 64, diag-nostic sherds were found in thefreshwater marsh unit (0.931.33 mabove present sea level a.s.l.) and thepalaeosol (1.331.52 m a.s.l.) and

were dated to Roman to Byzantinetimes (Lang, 2005, pers. comm.). Asthe OIN 65 ceramic findings belongto the same facies units it is assumedthat they are also of Roman toByzantine age. Bedrock encounteredat OIN 64 was not affected by marinebioerosion and a lagoonal unit ismissing. The sedimentary sequenceof OIN 69, drilled some 50 m north

of the bedrock outcrop, is similar to OIN 65, but shows athick stratum of well sorted fluvial sand. As the profile is voidof ceramics, anthropogenic activity seems to have been con-centrated on the outcrop itself.

14C-AMS dating of a rock boring mussel from the (supra-)littoral zone at OIN 69 (2.92 m b.s.l.) showed that bio-ero-sion took place until 30602915 cal BC (sample OIN 69/13ST/M/BE; fig. 7a, table 1). At the same time, peat startedgrowing at OIN 44 (sample OIN 44/20+ PR: 30882926 calBC, 4.83 m b.s.l.; fig. 7a, table 1). The change from bio-ero-sion to peat formation was caused by a major shift in coastaldynamics. It is known that an Acheloos River distributaryreached OIN 49 (transect II) shortly after 32612925 cal BC(sample OIN 49/15+ PR; fig. 6, table 1). This distributaryhad already passed by south of the bedrock outcrop close to

OIN 44 and OIN 69 (transect III) shortly before 30882926cal BC (sample OIN 44/20+ PR; fig. 7a, table 1), i.e. almostat the same time. The distributary, rapidly prograding west-ward, sealed off a part of the lagoon southeast of Trikardoand induced quiescent hydrodynamic conditions favourableto peat formation at a site where, shortly before, rocks insupra-littoral position were affected by marine bio-erosion.The radiocarbon dated wood fragment from OIN 69 (sampleOIN 69/14 HR: 28922702 cal BC, 3.21 m b.s.l.; fig. 7a,table 1) is assumed to have been washed in after bio-erosionhad already stopped.

It is suggested that bio-erosion at OIN 65 occurred at the

same time as found for OIN 69. The14

C-AMS dated juveni-le specimens of brackish gastropod species encountered atOIN 65 (sample OIN 65/14 M2: 13751247 cal BC; fig. 7a,


Andreas Vtt

Fig. 7a Distribution pattern of sedimentary facies in Trikardos southeastern harbour

(transect III).

Fig. 7a Chronostratigraphie des facis sdimentaires du port sud-est de Trikardo

(transect III).

Fig. 7b Distribution pattern of sedimentary facies in Trikardo

southeastern harbour (transect IV).

Fig. 7b Chronostratigraphie des facis sdimentaires du port

sud-est de Trikardo (transect IV).


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table 1) originate from quiescentlagoonal waters and seem to havepossibly been thrown on top of therocky shore around 1300 cal BC bywave action. Earth resistivity tomo-graphy gives a clear picture of the

bedrock outcrop showing that itsnorthern and southern flanks aresteeply inclined (oin-g-5, fig. 11). Alarge river channel to the north of theoutcrop is assumed to be responsiblefor the deposition of fluvial sedi-ments at OIN 69.

Cores OIN 66 and 67 were drilledbetween the outcrop and Trikardo(figs. 1, 2 and 7b). Bedrock was en-countered in both profiles. Thisproves that, in former times, a WE

trending rocky promontory existedwhich is now partly covered by allu-vial deposits. At OIN 68, river chan-nel sediments include numerousweathered ceramic fragments whichseem to be associated to the Romanto Byzantine sherds found in adja-cent overbank marsh deposits atOIN 64 and 65. Geoelectric measure-ments along a W-E transect (oin-g-6,fig. 11) show that the fluvial sedi-ments of OIN 68 were deposited by alarge meandering Acheloos Riverchannel east of the bedrock outcrop.It is still unclear, however, whetherfluvial deposition was linked to natu-

ral crevasse dynamics or to an artificial canal. Thefact that soil formation occurred on the top of themarsh deposits at OIN 64, 65 and 69 indicates thatsediment supply by the Acheloos River stoppedsome time after Roman to Byzantine times.

To summarize, our results show (i) that the south-eastern part of Trikardo lay on the rocky shore of a

large lagoon until about 3000 cal yr BC, (ii) that anAcheloos distributary passed by shortly afterwardsin a westward direction and induced quiescent hy-drodynamic and locally swampy conditions and(iii) that an Acheloos meander existed near therocky promontory southeast of Trikardo duringRoman to Byzantine times. From an archaeologicalpoint of view, it appears (i) that Trikardo was colo-nized in early Helladic times, (ii) that, then, a har-



Fig. 8 Bedrock outcrop southeast of Trikardo. Remains of a wall with abundant ceramic frag-

ments dating to Roman to Byzantine times (small photo to the left, white arrows), as well as with

a flint of probably prehistoric age (small photo to the right). Ceramic findings in vibracores revea-

led that the bedrock was used as a quay on a lagoonal shore during early Helladic times

(OIN 44) and at the riverside of a large Acheloos meander during Roman to Byzantine times

(OIN 64, 65). Nowadays, the site is almost completely covered by alluvial deposits. The left back-

ground shows Oiniadais acropolis, the right middleground the entrance to the necropolis bay.

View to the northwest (photos taken by Vtt, 2005).

Fig. 8 Affleurement du substrat au sud-est de Trikardo. Les vestiges dun mur et de nom-

breux fragments de cramique tmoignent dune occupation humaine aux priodes romaine et

byzantine (petite photo gauche, flches blanches). Un clat de silex (petite photo droite) date

vraisemblablement des temps prhistoriques. La prsence de cramiques indique que laffleu-

rement rocheux servait de quai sur la berge dune lagune, lpoque Helladique Ancien(OIN 44), et sur la berge dun vaste mandre de lAcheloos aux priodes romaine et byzantine

(OIN 64, 65). De nos jours, le site est compltement colmat par des alluvions. La photographie

densemble reprsente lacropole dOinaidai. Vue vers le nord ouest (clichs Vtt, 2005).

Fig. 9 Distribution pattern of sedimentary facies in

the necropolis bay of Oiniadai (transect V).

Fig. 9 Chronostratigraphie des facis sdimentaires

de la baie de la ncropole dOiniadai (transect V).


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Fig. 10a Bivalves and gastropods encountered

in sediment samples of vibracore OIN 10 (tran-

sect V), compared to grain size distribution.

Fig. 10a Granulomtrie et contenu malacolo-

gique des chantillons de la carotte OIN 10 (tran-

sect V).

Fig. 10b Species and associations of ostracods and foraminifers encountered in sediment samples of vibracore OIN 10 (transect

V), compared to grain size distribution.

Fig. 10b Analyse des ostracodes et des foraminifres identifis au sein de la carotte OIN 10 (transect V).


Andreas Vtt


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bour existed on the shore of a swampy lagoon at the south-eastern fringe of the island and (iii) that in the same area,people were living on the banks of a large Acheloos mean-

der during Roman to Byzantine times.

The necropolis embayment

The necropolis bay, located east of the acropolis, extendsalmost 250 m both in NS and in EW direction (figs. 1 and2). The ancient main road to Oiniadai runs above the north-ern shore of the bay where recent archaeological excava-tions have revealed the remains of the necropolis. The roadleads towards the main gate of the polis (Powell, 1904: 157).

Transect V consists of two vibracores, one in the northernpart of the indentation (OIN 70), the other some 650 m fur-

ther east (OIN 10) in the open alluvial plain. The base ofOIN 10 shows sand bar deposits of a NESW runningtombolo system between the Lesini mountains and Trikardo

which was formed during an early phase of westward deltaprogradation from the area around Katochi (Vtt et al.,2007a). An intermediate phase of lagoonal conditions is

documented by both macro- and microfaunal indicators(figs. 9, 10a and 10b). Subsequently, rising sea level anddecreased sediment supply during the 6th and 5th millenniaBC when the main distributary of the Acheloos River deltaapproached Trikardo from a northern direction (see above,Vtt et al., 2007a) allowed the tombolo to become partiallysubmerged and favoured predominantly shallow marineconditions. Increased saltwater influence resulted in a highbiodiversity (figs. 10a and 10b). The Acheloos River dis-tributary which approached Trikardo from the north causeda prodeltaic facies and later induced lagoonal conditions atOIN 10. The lagoonal environment east of the necropolis

bay lasted at least until the end of the 4th millennium BC(sample OIN 10/19 M: 34823372 cal BC; fig. 9, table 1).A subsequent change in the flow direction of the Acheloos



Fig. 11 Simplified inverse model resistivity sections for the southeastern harbour and the necropolis bay based on earth resisti-

vity measurements. Logs represent simplified facies profiles of vibracores.

Fig. 11 Profils golectriques du port sud-est et de la baie de la ncropole. Les logs reprsentent schmatiquement les facis

des carottes.


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distributary led to the partial erosion of lagoonal depositsand the accumulation of deltaic sand, several metres thick.

Shallow marine conditions at OIN 70, located in a shel-tered position, were not affected by prodelta dynamics. Thesubsequent lagoonal phase set in around 43064164 cal yrBC (sample OIN 70/15 M: 43064164 cal BC; fig. 9,

table 1) which shows good correspondence with the resultsobtained for OIN 47 (see fig. 3). Sedimentary facies changedwhen the site came under strong fluvial influence some timeafter 14191314 cal BC (sample OIN 70/10+ PR; fig. 9,table 1), and this is documented by fine sandy intercalations,reduced salinity and a lighter colour of the lagoonal deposits.At OIN 70, lagoonal deposits reach up to 2.69 m b.s.l. Com-pared to the relative sea level evolution near Trikardo (Vttand Brckner, 2006; Vtt et al., 2007a; Vtt, 2007), it is con-cluded that the lagoon persisted until circa 250 cal AD.Then, conditions turned limnic and the bay was filled upwith alluvial sediments.

Earth resistivity tomography along a SENW transect eastof the indentation revealed a wide zone of low conductivityvalues, almost 350 m wide, extending from around 6 m b.s.l.to the terrain surface and corresponding to the deltaic sedi-ments encountered at OIN 10 (oin-g-9, fig. 11). Similarfindings were made in geoelectrical profiles oin-g-5 andoin-g-6 (fig. 11). The distributary reached OIN 10 and pro-graded towards the west where it came into contact with theTrikardo hill. River water flowed into the necropolis bayand deposited fluvial sediments at the entrance to the north-ern harbour (OIN 54, OIN 47). Fluvial influence in the east-ern (OIN 70) and northern (OIN 47) embayments of Trikar-do started quasi contemporaneously between 1300 and1000 cal BC (samples OIN 47/14+ M and OIN 70/10+ PR;figs. 3 and 9, table 1). From that time on, lagoonal condi-tions in these bays were characterized by ongoing riverwater input. Later, when a large river meander was formedeast of Trikardo, a channel branched off near OIN 70 andfollowed the eastern and northern flanks of the hill. This isshown by Corona satellite photos (USGS, 1965) as well asby younger generation river channels detected by earth re-sistivity tomography (fig. 11). The 14C-AMS date obtainedfor the uppermost sample of OIN 70 (sample OIN 70/8+ M:13631230 cal BC; fig. 9, table 1) turns out to be unreliablewhen compared to relative sea level evolution.

In summary, the sedimentary sequences encountered inthe northern harbour (OIN 47) and in the necropolis bay(OIN 70) are almost identical. They show thick lagoonalunits strongly influenced by fluvial input that started around13001000 cal BC. The lagoonal environment, stronglyaffected by Acheloos River water inflow, persisted untilabout 250 cal AD. Although there is no information on har-bour installations in the necropolis bay, natural conditionswere highly appropriate for a port in Antiquity. The site wasprotected by the acropolis and lay close to the main roadtowards the city. It thus represented an ideal position for acommercial harbour. In this regard, further archaeological

and geomorphological research is needed to confirm thishypothesis.

Discussion

Many ancient accounts on Oiniadai unanimously describethe site as well protected by the surrounding swampy low-lands and mention that it is located at the riverside of theAcheloos (Freitag, 1994; Vtt et al., 2007b). Strabo

(63 BC26 AD), for instance, noted that Trikardo lies70 stades (about 13 km) distant from the river mouth at histime (Strabo 10, 2, 21). However, there is no specific infor-mation on the harbours of the polis. Only Polybius(210127 BC) reported that, in 219 BC, Philip V intendedto incorporate the harbour and the dockyard into the exist-ing fortification system and shipped building material toOiniadai via the Acheloos River (Polybius 4, 65, 29).

The northern harbour

Leake (1835, vol. III: 564ff.) and Sears (1904: 227, 235)

speculated that a canal independent from the Acheloos Riverguaranteed the communication of the northern harbour withthe sea. Heuzey (1860: 447f.), Lolling (1876/77: 282) andPhilippson (1958: 402ff.) were convinced that this canal wasconnected to the main stream. Lang (1905: 29ff.) andLehmann-Hartleben (1923: 80) suggested that the northernport opened to a marine embayment or to a lagoon. So didKirsten (1937: 2207). He also thought that a bayou of theAcheloos River supplied additional inflow to the harbour.Freitag (1994: 232) and Fouache et al. (2005) concludedthat the city lay at the marine front. Villas (1984: 115), how-ever, had already vibracored in the harbour basin and foundlagoonal deposits for the time when the shipsheds were inuse (Murray, 1982: 40ff.).

Our data are in good agreement with the accounts of theancients and confirm Villas (1984) results: in antiquity, thenorthern harbour communicated with the Ionian Sea via alagoon, the Lagoon of Oiniadai, into which an AcheloosRiver channel discharged freshwater (figs. 1, 2, 3 and 5).The channel partly entered the northern harbour and thusdecelerated its silting up (Vtt et al., 2004). FollowingKirsten (1937: 2207) and Freitag (1994: 232), the Lagoon ofOiniadai is not the Lake Melite of the ancients. The lattershould rather be located between Trikardo and Skoupas(Vtt et al., 2007a).

The southern embayment

Murray (1982: 43) suggested that the southern embay-ment may have been used as harbour. He interpreted anearthen dam amidst the marshy ground as a pier. Accordingto OIN 49 and earth resistivity data, the inner section of theindentation was instead probably used to retain freshwaterfrom the adjacent karstic springs, i.e. as a reservoir fordrinking water (see above, figs. 2, 5 and 6). The dam wasprobably constructed by peasants after the city was aban-doned in order to cross the swamp on dry ground. If there

was a harbour at all during ancient times, it must have beenoutside the wall. Landing would have been possible at the


Andreas Vtt


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shore of the fluviomarine channel encountered at OIN 63 aswell as on the adjacent lagoonal shores.

The southeastern harbour and the necropolisembayment

Based on Polybiuss accounts, Leake (1835, vol. III: 168)and Heuzey (1860: 455) were convinced that, during Clas-sical-Hellenistic times, there was another harbour at theriverside southeast of the island. They argued that Philip Vwould not have had to incorporate the shipsheds into the for-tification system as they were already part of it (contra:Murray, 1982: 36ff). Bursian (1862: 122), Oberhummer(1887: 245), Weil (1903: 344) and Philippson (1958: 403)adopted their view whereas Lehmann-Hartleben (1923:110f) and Kirsten (1937: 2207) rejected it.

Our studies revealed an early Helladic harbour southeastof Oiniadai along the swampy shore of a lagoon (figs. 7a

and 7b). In addition to the findings of a submerged earlyHelladic settlement in the Bay of Platiyali near Astakos(Delaporta and Spondylis, 1990; Delaporta et al., 1990), thisis another proof of early Bronze Age human activity inAkarnania. The lagoon east of Oiniadai was strongly affect-ed by river water inflow since 13001000 cal BC andexisted until 250 cal AD (see above). Earth resistivitytomography revealed a former promontory of Trikardo, nowpartly covered by alluvial deposits, which may have beenused as a quay during Classical-Hellenistic and Romantimes. The bedrock surface at OIN 64, OIN 68 and OIN 69reaches up to 2.782.42 m b.s.l. According to the local sealevel curve (Vtt and Brckner, 2006; Vtt et al., 2007a;Vtt, 2007) it should have been possible to use the promon-tory as a quay until around 250 cal AD (figs. 7a, 7b and 11).Saltwater influence at OIN 65, OIN 68 and OIN 69, howev-er, persisted up to around 2.10 m b.s.l. Presumably, this isdue to landward saltwater inflow via the Acheloos Rivermeander which flowed by close to the promontory duringRoman to Byzantine times and which was used as a riverharbour. However, further research will be necessary toachieve a better temporal resolution for the palaeogeograph-ical situation around the promontory during antiquity. Itseems further probable that, during Classical-Hellenisticand Roman times, a commercial harbour existed at the

necropolis bay which similar to the conditions found forthe northern harbour was affected by considerable fresh-water input by an Acheloos River channel running along theeastern and northern flanks of Trikardo (figs. 9 and 11).

Murray (1985) localized ancient Nasos on the formerisland of Skoupas and suggested that it was founded between252219 BC when manoeuvering to Oinidais harbours hadbecome difficult due to ongoing siltation. Cargo and passen-gers could have been shipped to Trikardo on flat-bottomedriver boats (Murray, 1985: 106). Vtt et al. (2004, 2007a)showed that Skoupas was at the seafront until late Byzantinetimes and that during Classical-Hellenistic to Roman times,

the main mouth of the Acheloos River delta lay southeast ofthe island representing an ideal waterway in a shallow water

lagoonal system. Although it has to be expected that the peo-ple of Oiniadai were aware of the silting up of their harbours,sedimentological evidence of dredging was not encountered(Marriner and Morhange, 2006).

Conclusions

Based on sedimentological, geochemical, macro- andmicrofaunal and palynological analyses of sediment sam-ples from 15 vibracores, on the relative age determination ofceramic fragments as well as on 22 14C-AMS dates, the fol-lowing conclusions can be made.

(i) Around 3000 cal yr BC, in early Helladic times, a west-ward prograding distributary of the Acheloos River deltainduced swampy conditions in the lagoon at the southeast-ern fringe of Trikardo. The quiescent environment was usedas waste dump and port by early Helladic fishermen. Arocky promontory, nowadays covered by alluvial deposits,

served as natural quay (figs. 1, 2, 7a, 7b, 8 and 11).(ii) Around 13001000 cal yr BC, in late Helladic times,an Acheloos River distributary approached Trikardo andflowed along its eastern and northern flanks. Lagoonal envi-ronments in the necropolis bay as well as in the northernembayment thus were strongly affected by freshwaterinflow (figs. 1, 2, 3, 5, 9 and 11). Both bays representedideal harbour sites. The natural quay in the southeast waspossibly still in use. Further archaeological studies, howev-er, are needed to clarify if Trikardo was populated at all atthat time.

(iii) Until Classical-Hellenistic to early Roman times, thenorthern harbour basin still experienced considerable riverwater inflow. The shipsheds were connected to the IonianSea via a lagoonal system intruding from western direction.The harbour finally silted up around 1 BC/AD (figs. 1, 2, 3and 5). The necropolis bay offered similar anchoring condi-tions (figs. 9 and 11). The southeastern promontory wasprobably still used as a wharf on a lagoonal shore. Later,until Roman to Byzantine times, a harbour existed along theriverbank of a nearby Acheloos meander (fig. 7a and 7b).

(iv) The inner section of the southern embayment neverserved as a harbour. Simple landing sites may have existedoutside the city wall (figs. 1, 2, 5 and 6).

It could be shown that Trikardo was of great importance

as a seaport during 4000 or so years of human activity onthe former island. However, the people of Trikardo neverhad a harbour on the sea frond. Instead, they preferred qui-escent lagoonal environments and used the Acheloos Riverchannels as waterways and to protect their harbour basinsfrom rapid siltation. Thus, Oiniadais northern harbour,clearly documented by the archaeological remains of theshipsheds, simply represents an outstanding example of ahistory for intense and changind interactions betweenmankind and the sea.

Acknowledgements

Sincere thanks are due to H. Brckner, A. Schriever(Marburg), J.C. Kraft (Delaware), I. Mariolakos and




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I. Fountoulis (Athens) for fruitful discussion and criticalremarks. I thank L. Kolonas (Athens) and M. Stavropoulou(Mesolongion) for support during field campaigns. Macro-and microfossil analyses were carried out by M. Handl(Marburg), palynological studies by S. Jahns (Berlin) andearth resistivity measurements by R. Herd (Cottbus). Ra-

diocarbon dating was done by K. van der Borg (Utrecht)and A. Scharf (Erlangen). F. Lang (Berlin/Darmstadt) de-termined the age of ceramic fragments. Work permits wereissued by C. Perissoratis, IGME (Athens). I am indebted to J. Strube (Marburg) and M. Besonen (Amherst) for cor-recting my English. I gratefully acknowledge funding of theproject by the German Research Foundation (DFG, Bonn,Gz. VO 938/1-3).

References

Besonen M., Rapp G.R., Jing Z. (2003) The lower Acheron

River valley: ancient accounts and the changing landscape. InWiseman J., Zachos K. (Eds.):Landscape Archaeology in South-ern Epirus, Greece I. The American School of Classical Studiesat Athens, Athens, Hesperia Supplement, 12, 199-263.

Bousquet B. (1976) La Grce occidentale. Interprtation go-morphologique de lEpire, de lAcarnanie et des les Ioniennes.Thse de luniversit Paris-Sorbonne. Atelier de reproduction

des thses de Lille III, Honor Champion, Paris, 585 p.

Bousquet B., Dufaure J.-J., Pchoux P.-Y. (1987) Ports

antiques et lignes de rivages gennes. In Trousset P. (Ed.):Dplacements des lignes de rivage en Mditerrane daprs lesdonnes de larchologie. Actes Coll. Int. Aix-en-Provence, 5-7sept. 1985. Paris, Centre National de la Recherche Scientifique,

137-153.

Brckner H. (2005) Holocene shoreline displacements and their

consequences for human societies: the example of Ephesus in

western Turkey. Zeitschrift fr Geomorphologie N.F., Suppl.,137, 11-22.

Brckner H., Mllenhoff M., Gehrels R., Herda A., Knipping

M., Vtt A. (2006) From archipelago to floodplain geogra-

phical and ecological changes in Miletus and its environs during

the last six millennia (Western Anatolia). Zeitschrift fr Geo-morphologie N.F., Suppl., 142, 63-83.

Bursian C. (1862) Geographie von Griechenland I: Das nrd-liche Griechenland. Teubner, Leipzig, 384 p.

Delaporta A., Spondylis I. (1990) Un habitat Helladique AncienII Platiyali Astakou. In Tzalas H.E. (Ed.): Proceedings, 2nd

International Symposium on Ship Construction in Antiquity,Delphi, 27-29 August 1987, 127-134.

Delaporta A., Spondilis E., Baxevanakis Y. (1990) Platiyali-

Astakos: a submerged Early Helladic site in Akarnania.EnaliaAnnual, 1, 44-46.

Fouache E. (1999) Lalluvionnement historique en Grce occi-

dentale et au Ploponnse gomorphologie, archologie,

histoire. Bulletin de Correspondance Hellnique, Supplment,Athnes, 35, 1-235.

Fouache E., Mnanteau L., Dalongeville R. (1998) Lapport

de la photo-interprtation et de la tldtection dans ltude duport dOeniades (Grce). Les Nouvelles de lArchologie, 74,28-31.

Fouache E., Dalongeville R., Kunesch S., Suc J.-P., Subally D.,

Prieur A., P. Lozouet P. (2005) The environmental setting of

the harbour of the Classical site of Oeniades on the Acheloos

Delta, Greece. Geoarchaeology, 20/3, 285-302.Freitag K. (1994) Oiniadai als Hafenstadt. Einige historisch-

topographische berlegungen. Klio, 92, 212-238.

Frenzel P., Boomer I. (2004) The use of ostracods frommarginal marine, brackish waters as bioindicators of modern and

Quaternary environmental change. Palaeogeography, Palaeocli-matology, Palaeoecology, 225/1-4, 68-92.

Haslinger F., Kissling E., Ansorge J., Hatzfeld D., Papadimi-

triou E., Karakostas V., Makropoulos K., Kahle H.-G., Peter

Y. (1999) 3D crustal structure from local earthquake tomogra-

phy around the Gulf of Arta (Ionian region, NW Greece).

Tectonophysics, 304, 201-218.Heuzey L. (1860)Le Mont Olympe et lAcarnanie. Firmin Didot,

Paris, 463 p.

Institute of Geology and Mineral Exploration, IGME (1989)

Geological map of Greece, 1:50,000. Echinades Sheet. Athens.Kirsten E. (1937) Oiniadai.In Kroll W. (Ed.): Paulys Real-En-cyclopdie der classischen Altertumswissenschaft. SiebzehnterBand, Vierunddreissigster Halbband, Numen Olympia, Stutt-

gart, 2204-2228.

Kolonas L. (1992) Excavations at Oiniadai. The shipsheds.

Archaiognosia 6, 153-159 [in Greek].Kraft J.C., Rapp G.R., Szemler G.J., Tziavos C., Kase E.W.

(1987) The pass at Thermopylae, Greece. Journal of FieldArchaeology, 14/2, 181-198.

Kraft J.C., Rapp G.R., Kayan I., Luce J.V. (2003) Harbor

areas at ancient Troy: Sedimentology and geomorphology com-

plement to Homers Iliad. Geology, 31/2, 163-166.Lang G. (1905) Untersuchungen zur Geographie der Odyssee.

Gutsch, Karlsruhe, 122 p.

Leake W.M. (1835) Travels in northern Greece. Rodwell, Lon-don, 4 volumes.

Lehmann-Hartleben K. (1923) Die antiken Hafenanlagen des

Mittelmeeres. Klio-Beiheft, Leipzig, 14, 304 p.Lolling H.G. (1876/1877) Reisenotizen aus Griechenland 1876

und 1877. Herausgegeben vom Deutschen ArchologischenInstitut Athen und der Carl Haller von Hallerstein-Gesellschaft,

Mnchen, bearbeitet von B. Heinrich, eingeleitet von H. Kalcyk

(1989). Reimer, Berlin, 827 p.

Marriner N., Morhange C. (2006) Geoarchaeological evidence

for dredging in Tyres ancient harbour, Levant. QuaternaryResearch, 65, 164-171.

Mllenhoff M. (2005) Geoarchologische, sedimentologische

und morphodynamische Untersuchungen im Mndungsgebiet

des Byk Menderes (Mander), Westtrkei. MarburgerGeographische Schriften, Marburg/Lahn, 141, 1-282.

Murray W.M. (1982) The coastal sites of western Akarnania: atopographical-historical survey. Ph. D. thesis, University ofPennsylvania, 558 p.

Murray W.M. (1985) The location of Nasos and its place in

history.Hesperia, 54, 97-108.Oberhummer E. (1887) Akarnanien, Ambrakia, Amphilochien,

Leukas im Altertum. Ackermann, Mnchen, 330 p.Philippson A. (1958)Die Griechischen Landschaften. Eine Lan-deskunde. Band II: Der Nordwesten der Griechischen Halbinsel.


Andreas Vtt


18/19

Teil II: Das westliche Mittelgriechenland und die westgriechi-schen Inseln. Klostermann, Frankfurt, 394 p.

Poppe G.T., Goto Y. (1991)European seashells. Volume I: Poly-placophora, Caudofoveata, Solenogastra, Gastropoda. Hemmen,

Wiesbaden, 352 p.

Powell B. (1904) Oeniadae. History and topography.American

Journal of Archaeology, 8/2, 137-173.Reimer P.J., McCormac F.G. (2002) Marine radiocarbon reser-

voir corrections for the Mediterranean and Aegean Seas.

Radiocarbon 44, 159-166.Sears Jr. J.M. (1904) Oiniadae. The ship-sheds.American Jour-

nal of Archaeology, 8/2, 227-237.Stanley D.J., Warne A.G. (1994) Worldwide initiation of

Holocene marine deltas by deceleration of sea-level rise. Science265, 228-230.

Stuiver M., Reimer P.J., Reimer R. (2006) CALIB RadiocarbonCalibration. http://calib.qub.ac.uk/calib [last access: March 31,2006].

Villas C. (1984) The Holocene evolution and environments ofdeposition of the Acheloos River delta, northwestern Greece .Unpublished master thesis, University of Delaware, Department

of Geology, 222 p.

Vtt A. (2007, in press) Relative seal level changes and regional

tectonic evolution of seven coastal areas in NW Greece since the

mid-Holocene. Quaternary Science Reviews.Vtt A., Brckner H. (2006) Versunkene Hfen im Mittelmeer-

raum. Antike Kstenstdte als Archive fr die Kultur- und

Umweltforschung. Geographische Rundschau, 58/4, 12-21.Vtt A., Brckner H., Handl M. (2003) Holocene environ-

mental changes in coastal Akarnania (northwestern Greece).

In Daschkeit A., Sterr H. (Eds.):Aktuelle Ergebnisse der K-stenforschung. 20. AMK-Tagung, Kiel, 30.05.-01.06.2002.Berichte aus dem Forschungs- und Technologiezentrum West-

kste der Christian-Albrechts-Universitt zu Kiel, Bsum, 28,

117-132.

Vtt A., Brckner H., Schriever A., Handl M., Besonen M., van

der Borg K. (2004) Holocene coastal evolution around theancient seaport of Oiniadai, Acheloos alluvial plain, NW Greece.

In Schernewski G., Dolch T. (Eds.): Geographie der Meere undKsten. Coastline Reports, Rostock-Warnemnde, 1, 43-53.

Vtt A., Schriever A., Handl M., Brckner H. (2007a, in press)

Holocene palaeogeographies of the central Acheloos River

delta (NW Greece) in the vicinity of the ancient seaport Oinia-

dai. 6th Intern. Conf. Geomorph., Sept 7-11, 2005, Zaragoza,

Working Group Session on Geoarchaeology. Geodinamica Acta,special issue (Ed.: Fouache E.).

Vtt A., Schriever A., Handl M., Brckner H. (2007b, in press)

Holocene palaeogeographies of the eastern Acheloos River

delta and the Lagoon of Etoliko (NW Greece). Journal ofCoastal Research.Vouvalidis K.G., Syrides G.E., Albanis K.S. (2005) Holoce-

ne morphology of the Thessaloniki Bay: Impact of sea level

rise. Zeitschrift fr Geomorphology N.F., Suppl. Vol., 137,147-158.

Weil R. (1903) Oeniadae. Ein Beitrag zur nordgriechischen

Reise des Cyriacus von Ancona (1436). August Wilmanns zum

25. Mrz 1903,Beitrge zur Bcherkunde und Philologie, Leip-zig, 341-354.

Article reu le 9 juin 2006, accept le 31 janvier 2007.




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