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PONTICA
XLVIII‐XLIX
2015‐2016
MUZEULDEISTORIENAŢIONALĂŞIARHEOLOGIE
CONSTANŢA
NEWGEOARCHAEOLOGICALRESEARCHES
AROUNDTHEDANUBIANISLANDPĂCUIULLUISOARE
GlicherieCARAIVAN
RaduDIMITRIU
ConstantinCHERA
CorneliuCERCHIA
Keywords:seismo‐acousticsurvey,underwatergeo‐archaeology,Byzantine
fortress,DanubeRiver.
Cuvinte‐cheie:cercetăriseismo‐acustice,geoarheologiesubacvatică,fortăreaţă
bizantină,fluviulDunărea
Abstract:TheerodedruinsofaByzantinefortress(10th‐13thcenturies)stillendure
ontheDanubianislandPăcuiulluiSoare,between355and357km.Aseismo‐acoustic
surveycarriedoutalongtheDanubeinfrontoftheislandoutlinedthepresenceofthe
fortress’ruinsundertheriverwaters.TheexposedfortressonthePăcuiulluiSoare
islandhasasurfaceofabout7500m2,whiletheunderwaterfortressisfourtimeslarger
(28750m2).
Rezumat:Ruineleerodatealeuneicetățibizantine(secoleleX‐XIII)încămairezistă
peinsuladunăreanăPăcuiulluiSoare,întrekm355și357.Unstudiuseismo‐acustic
efectuatde‐alungulDunării,înfațainsulei,aevidenţiatprezențaruinelorcetățiisubapele
râului.CetateaexpusădepeinsulaPăcuiulluiSoareareosuprafațădeaproximativ7500
m2,întimpcefortăreațadesubapăestedepatruorimaimare(28750m2).
Introduction
OntheDanubianislandPăcuiulluiSoare,(coordinates:NE‐44°8ʹ05.48ʺN;
27°28ʹ14.33ʺEandSW‐44°7ʹ44.65ʺN;27°28ʹ 02.60ʺE),theruinsofaByzantine
fortressfromthe10th‐13thcenturiesarestillpresent,manyofwhichhavealready
beenerodedbytheDanubeRiver(Fig.1).
GlicherieCARAIVAN,RaduDIMITRIU,CorneliuCERCHIA:NationalInstituteof
MarineGeologyandGeo‐ecology(GeoEcoMar),Constanta,Romania:bd.Mamaiano.304,
email:gcaraivan@geoecomar.ro;dimitriu@geoecomar.ro;corneliu.cechia@geoecomar.ro
ConstantinCHERA:MuseumofNationalHistoryandArcheologyConstanta,Ovidiu
Square12,email:anroed@hotmail.com.
GLICHERIECARAIVANetalii
490
Fig.1‐LocationoftheByzantinefortress
onPăcuiulluiSoareisland.DigitalGlobe.
Inthenortheasternpartoftheisland,hiddeninadenseforest,thewallruins
oftheoldByzantinefortressarepresentuptotheislandshore,suggestingtheir
continuityundertheDanubewaters.Thefortresswasbuiltbetween972–976
yearsB.P.,bytheEmperorJohnTzimiskes’troopsandreflectstheByzantine
strengthintheLowerDanube.
AlthoughnoRomanarchaeologicallevelwasidentifieduptodate,itis
assumedthattheByzantinesbuiltthefortressontheruinsofanoldercity,
reusingthebuildingmaterial.Theyalsoputintopracticeanewtechnique,
provingthecompetenceandabilityofthemanufacturers.
Twomethodswereusedtostabilizethewalls’foundationonthenon‐
consolidatedalluvialsubstrate:(a)adeepfoundation,whichrequiredalarge
effortorawooden(oakbeams)sub‐constructionandalargeamountofstoneas
well,or(b)thewallfoundationwasmadeofburnedoakstakesstuckinthe
groundatregularintervals,overwhichthemanufacturersplacedoakbeams,both
longitudinallyandtransversely.Theemptyspaceswerefilledwithmortar
(masonry)‐amixtureoflime,gravelandgrated/shreddedstone.Inthecaseof
PăcuiulluiSoareByzantinefortress,thelatterapproachwasused.
Modernunderwaterremotesensingtechniquesintroducemanyadvantages
totheunderwaterarchaeology,particularlytothedetectionofsubmergedman‐
madestructuresofarchaeologicalinterest.Thisworkpresentsthepreliminary
resultsofaseismo‐acousticandmagnetometricsurveyintheDanubeRiver
aimingtofindtheruinsofaByzantinefortressontheriverbed.
RESEARCHESAROUNDPĂCUIULLUISOARE
491
Materialandmethods
Inthefallof1987,asedimentologicalandseismo‐acousticsurveywas
carriedoutbyGeoEcoMarontheRomanianDanuberoute.Theseismo‐acoustic
profilingwasconductedusingtheultrasonicsurveymethodwithcontinuous
recording(verticalsonar).Ahigh‐frequencytransmittergeneratesasoundwave
thatpropagatesthroughthewaterlayerwithaspeedofabout1500m/secand
reflectsatthewater/sedimentinterface,beingreceivedbyatransducer
(hydrophone),locatedinthesameplacewiththetransmitter.Thepulselength
generatedbythetransmitterhasamagnitudeorderofmillisecondsandtheissue
rateof1second.Thebottomreflectedsignalwasrecordedonanelectro‐sensitive
paper,obtainingacontinuousprofilingduringthevessel’strackline.AnOcean
SonicsverticalsonarORS‐219withdryrecordingpaperandworkingemission
frequencyof8KHzwasusedduringthissurvey.Theequipmentwasmountedon
atugof600hp,withamaximumdraftof1.80m.Theoptimalconsideredspeedof
theresearchvesselwasaround13km/h.Thevessel’sroutefollowedtheriver
sailinglinetothePăcuiulluiSoareisland’sproximity(Fig.2).Thepositionand
navigationofthevesselwerecarriedoutusingaDGPSsystemwithanaccuracy
oflessthan1m.
Fig.2‐PăcuiulluiSoareFortressGPSposition‐44°7ʹ56.13ʺN;27°28ʹ16.35ʺE.
GLICHERIECARAIVANetalii
492
Fig.3‐TheNE‐SWprofile,between:NE‐44°8ʹ05.48ʺN;27°28ʹ14.33ʺEand
SW‐44°7ʹ44.65ʺN;27°28ʹ02.60ʺE.
Fig.4‐HypsometricmapoftheDanubeRiverinfrontoftheisland.
RESEARCHESAROUNDPĂCUIULLUISOARE
493
Fig.5‐MagnetometricanomalymapinfrontofPăcuiulluiSoareIsland.
Resultsanddiscussion
Thelongitudinalseismo‐acousticprofilemadeinfrontofthefortress,
showedaninformativeverticalpictureoftheDanubebed.Amound‐likefeature
isobtainedontheseismo‐acousticprofiletothenorthernwallofthefortress.This
featureappearsasasharpriseoftheDanubebottomhavingalengthofabout40
mandaheightof9mcomparedtothesurroundingriverbed.Theminimum
waterdepthoftheriverwasonly4.5m.Thisfeatureisdevelopedona
bathymetricbackgroundof14‐15m.Theacousticcharacteroftheseismo‐acoustic
GLICHERIECARAIVANetalii
494
profilesuggeststhehardnatureoftheraisedfeature,comparedwiththeusual
“anti‐dune”morpho‐dynamicstructuresofthesedimentarybed(Fig.3).The
presenceofthewell‐shapeddepressionsoftheDanubebeddownstreamand
upstreamoftheunderwaterraisedfeatureillustratesthehydrodynamic
conditions,inducedbythefortresswalls’underminingandflooding(Fig.3).
Upstreamofthemainbedlifting,somesmallpositiveruin‐shapedirregularities
arefoundontheDanubebottom,withaheightrangingfrom1.00to1.50m(see
Fig.2andFig.3).Theseismo‐acousticprofilealsoshowedtwosub‐bottom
discontinuousreflectorsfrom3to5mbelowtheriverbed,indicatingtheexistence
ofdifferentlithologicalcharacteristicslenses.TheByzantinefortresswallslocated
ontheislandofPăcuiulluiSoareendsharplyatthebankoftheDanube,
suggestingtheunderwatercontinuityoftheruinsundertheDanubeRiver
waters.Theseismo‐acousticsurveyconductedontheDanubeRivernearthe
PăcuiulluiSoareislandbringsanimportantgeophysicalargumentsupportingthis
hypothesis.Thesub‐bottomdiscontinuousreflectorsidentifiedontheseismo‐
acousticprofilecouldrepresentthewoodenfoundationonwhichthefortress
wallswerebuilt.WiththeDanubeflowregimechanges,theleftsideoftheisland
wassubjecttoenhancederosion,causingsub‐diggingofthefoundation’s
structure.In2003,whentheDanubewaterwasatverylowlevels,thewood
beamsnetworkwasclearlyvisible.
OntheeasternrightbankofthePăcuiulluiSoareisland,whereanarrow
branchseparatestheislandfromtheDobrogeanland,theerosionwasless
destructive.Therefore,thestructureswerepreservedingoodcondition(for
example,thewharf,andseeFig.2).
Magnetometricandbathymetricstudies
Ashortbutdismissivegeophysicalmappingofthesitewasalsocarriedout
inMay10‐12,2010,duringthecruisealongtheDanubeRiveroftheR/V“Istros”,
operatedbyGeoEcoMarInstitute.Thegeophysicalresearchcovereda1.2kmlong
sectionoftheriverandthelast0.6kmoftheOstrovsecondaryarm.Itconsisted
ofsynchronoussingle‐beam,dualfrequencybathymetryandhighresolution
magnetometry.Thetotallengthofthegeophysicallineswasaround53kmforthe
bathymetryand23kmformagnetometry.
Thebathymetricmap(Fig.4)givesadetailedviewoftheriverbedand
undoubtedlyhighlightsthesubmergedextensionofthebyzantinefortressona
wide,semicircularsurface(250mlengthalongtheriverand180moffthePăcuiul
luiSoareisland).Theheightofthesubmergedfortresswalls,highlightedby
bathymetry,israngingfrom2mtoover8mabovetheriverbed(Fig.4).
TheexposedfortressonthePăcuiulluiSoareislandhasasurfaceofabout
7500m2,whilethesubmergedfortressisfourtimeslarger(28750m2).
Despitethehugemagneticbipolaranomalyduetoamodern(recent)river
shipwreck,whichliesonthenorthernfoothill(flank,side)ofthefortresswall,at
over12mwaterdepth,thetotalfieldmagneticmappingwasabletopositively
distinguishmostofthesubmergedwalls.Thisisprobablyduetothepresenceof
firedbricksand/orallochthonousrawconstructionmaterials,withaboveaverage
magneticproperties,withinthewalls’structure(Fig.5).
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495
Conclusion
Thepreviousunderwaterseismo‐acousticsurveycarriedoutinfrontofthe
PăcuiulluiSoareislandfortressandtherecentlymadebathymetricand
magnetometricresearchesprovidestrongargumentsthattheremnantsofthecity
extendintheDanubeRiver.
Therefore,furthergeo‐archaeologicalresearchisrequiredinthestudied
area,throughacomprehensiveinterdisciplinaryprogram,involving
sedimentologicalandgeophysicalstudies,inconjunctionwithdirect
observations,specifictounderwaterarchaeology.Theproposedsurveywilllead
toabetterunderstandingofthehistoryofthecityaswellasthesedimentary‐
hydrodynamicevolutionoftheisland.
BIBLIOGRAPHY
BARNEA&STEFĂNESCU1971‐I.Barnea&St.Stefănescu,ThehistoryofDobrogea.
Vol.III.Byzantines,RomansandBulgariansattheLowerDanube,Bucharest,1971.
PANINetal.1977‐N.Panin,G.Salomie&V.Varodin,Bathymetricalresearchonthe
BlackSeacontinentalshelf,St.cerc.geol.‐Geofizica15(1977),p.57‐73.
CARAIVAN&ENESCU(1988)‐Gl.Caraivan&G.Enescu,Observațiiseismoacustice
înzona“PãcuiulluiSoare”,Pontica22(1988),p.85‐87.
CARAIVAN,FULGA&CHERA2010‐Gl.Caraivan,C.Fulga&C.Chera,Underwater
geoarchaeologicalsurveyinfrontoftheDanubianislandPăcuiulluiSoare(Romania)usingremote
sensingtechniques–preliminaryresults.Proceedingsofthe19thCBGACongress,
Thessaloniki,Greece,2010,p.519‐524.