September18th,2017BurlingtonHouse,GeologicalSocietyofLondon

ABSTRACTBOOKLET

SchedulefortheShackletonConference:MarineGeoscience,Past,Present,andFuture

MarineStudiesGroup

September18th,2017

BurlingtonHouse,GeologicalSocietyofLondon9:15-9:40–ArrivalandWelcome,CoffeeandTea(LibraryoftheGeologicalSociety)9:40–Introductiontothedayandconference(MemberoftheMSGCommittee)9:45–BillAustin,UniversityofStAndrews CraigSmeaton,XingqianCui,ThomasS.Bianchi,,AlixG.Cage,JohnA.Howe

ClimaticandhumandriversofHolocenecarbonburialalongtheNorthAtlanticmargin

10:00–ZviSteiner,UniversityofCambridge

BoazLazar,AdiTorfstein,JonathanErezTestingtheutilityofgeochemicalproxiesforpalaeoproductivityinoxicsedimentarymarinesettingsoftheGulfofAqaba,RedSea

10:15–KEYNOTE:CarrieLear,UniversityofCardiff. Icesheetstability:Apalaeoclimateperspective10:45–DavidHodell,UniversityofCambridge P.C.Tzedakis,L.C.Skinner,M.Vautravers,J.Rolfe,J.Nicolson

PersistentinstabilityofglacialclimateandoverturningcirculationintheNorthAtlanticforthepast1.5millionyears

11:00–CoffeeBreak11:15–KEYNOTE:RosalindRickaby,UniversityofOxford Theevolvingroleofphytoplanktoninthecarboncycle11:45–NickMcCave,UniversityofCambridge

DavidThornalleyandIanHallRelationofsortablesiltgrain-sizetodeep-seacurrentspeeds:Calibrationofthe‘MudCurrentMeter’

12:00–JennyCollier,ImperialCollegeLondonR.W.Allen,C.Berry,T.Henstock,F.J-Y.Dondin,J.L.Latchman,R.E.A.RobertsonTime-lapsebathymetricsurveysofanactivesubmarinevolcanoandimplicationsforhazardinthesouthernCaribbean

12:15–KEYNOTE:DamonTeagle,UniversityofSouthampton

Theformationandevolutionofnewcrustatoceanridges:TacklingafundamentalEarthsciencechallengefrommultipledirections

12:45–LunchandDiscussionandPosterSession13:45–KEYNOTE:RosalindCoggon,UniversityofSouthampton

TheSouthAtlanticdrillingproject,multi-disciplinarycollaborationsinmarinescience

14:15–RobLarter,BritishAntarcticSurvey

AlastairG.C.Graham,Claus-DieterHillenbrand,KellyA.Hogan,F.JavierHernandez-Molina,JamesE.T.Channell,ChuangXuan,DavidA.Hodell,MariaC.Williams,SimonJ.Crowhurst,KarstenGohl,MicheleRebesco,GabrieleUenzelmann-NebenandRRSJamesClarkRosscruiseJR298ScientificParty.DevelopmentofalargesedimentdriftnearthemouthofMargueriteTrough,AntarcticPeninsulaasarecordofpasticestreamdynamics

14:30–DanielaVendettuoli–UniversityofSouthampton

Clare,M.,Cartigny,M.,Hage,S,HughesClarke,J.,Talling,P.,Vellinga,A.,Waltham,D.

Thestratigraphicincompletenessofsubmarinechanneldeposits14:45–KEYNOTE-BobGatliff–BritishGeologicalSurvey

ABGSforwardlookatMarineGeoscienceintheUK:Prioritiesinatimeofchange

15:15–CoffeeBreak15:30–MikeClare–NationalOceanographyCentre,Southampton

Vardy,M.E.,Cartigny,M.J.B.,Talling,P.J.,Himsworth,M.D.,Dix,J.K.,Harris,J.M.,Whitehouse,R.J.S.,Belal,M.Howcanweuseemergingtechnologytodirectlymeasurepowerfulanddamagingdeep-seageohazards?

15:45–EdSelf–Gardline KenGames

3DseismicdataPast(exploration),Present(explorationandgeohazards)andFuture(exploration,geohazardsanddecommissioning)

16:00–KEYNOTE:RussellWynn-NationalOceanographyCentre,Southampton

Marineroboticsandtheirpast,presentandfutureapplicationsformarinegeoscience

16:30–NeilMitchell–UniversityofManchester

TheriseofinternationalcollaborationsinUKmarinesciencefrompublicationco-authorships

16:45–Closingdiscussionandmeetingwrapup

ListofPostersTheversatilityofpetrophysicaldatatohelpoceandrillingresearchLeBer,E.,Inwood,J.,Morgan,S.,Phillpot,L.,Davies,S.GeomorphometriccharacterisationofseabedfeaturesusingaGIS-basedsemi-automatedtoolboxJoanaGafeira,DiegoDiaz-Doce,LaurenceH.DeClippele,RobertGatliff

Howdoesmarinesedimentarymicrobialsulfatereductiondrivecalciumcarbonatepolymorphism?ChinYikLin,AlexandraV.Turchyn,ZvikaSteiner,PieterBots,GiulioI.Lampronti,NicholasJ.ToscaChallengerrevisited:Illuminatinganthropogenicclimatechangewith150yearsofoceanscienceLyndseyFox*,TomHill,StephenStukinsChangesinpalaeodeep-wateroxygenconcentrationsalongtheIberianMarginacrosstheMid-PleistoceneTransitionusingabenthicD13Cproxy.NicolaThomasandDavidHodellAnatomyoftheoldestknownHeinricheventsinMIS16atSiteIODP1308Abbie,P.B.Currington,MarylineJ.Mleneck-Vautravers,David,A.HodellMarineoperations:geologythroughtechnologyJosephHotherall,WillLewis,BobGatliff

AbstractsforOralPresentations

9:45ClimaticandhumandriversofHolocenecarbonburialalongtheNorthAtlanticmargin.

CraigSmeaton1,XingqianCui2,3,ThomasS.Bianchi2,AlixG.Cage4,JohnA.Howe5,WilliamE.N.Austin1,5*.

1SchoolofGeography&SustainableDevelopment,UniversityofStAndrews,StAndrews,KY169AL,UK2DepartmentofGeologicalSciences,UniversityofFlorida,Gainesville,FL32611,USA3DepartmentofEarth,Atmospheric,andPlanetarySciences,MassachusettsInstituteofTechnology,Cambridge,MA,USA4SchoolofGeography,GeologyandEnvironment,UniversityofKeele,Staffordshire,ST55BG,UK5ScottishAssociationforMarineScience,ScottishMarineInstitute,Oban,PA371QA,UKFjords are connectors between the terrestrial and marine systems and are known as globallysignificanthotspotsfortheburial(Smithetal.,2014)andlong-termstorage(Smeatonetal.,2016)ofcarbon (C). The glacial geomorphology of fjords and their catchment results in the terrestrial andmarineenvironmentsbeingstronglycoupledmoresothanotherestuarytypes.TheclearestexampleofthisistheterrestrialCsubsidytothesesediment,itisestimatedthatglobally55-62%ofCheldinfjordsedimentsareterrestriallyderived(Cuietal.,2016).YetitislargelyunknownhowclimaticandhumanforcingdrivesthetransferofterrestrialCtomarinesediments.Here,weexaminetheroleoflateHoloceneclimateandhumanactivityonthetransferofCfromtheterrestrialtomarineenvironmentalongtheNorthAtlanticMargin.LochSunartaScottishfjordsitsatthe land ocean interface of the North Atlantic. The catchment of the fjord has been shown to besensitiveto localandregionalclimaticchange(Gillibrandetal.,2005)andthefjordsedimentshavebeen able to record these changes in climate (Cage and Austin, 2010). Using a long (22 m)sedimentary recordwediscuss ourunderstandingofmid to lateHolocene regional climateand itsimpactonterrestrialCtransfertothecoastalocean.AlongsidethisweexaminetheroleofhumansonthelandscapeandtheirimpactonthetransferofterrestrialCtothecoastalocean.Theresultsfromthis study will further our understanding of the long-term drivers of terrestrial C transfer to thecoastalocean.PotentiallythisresearchprovidesinsightsonfutureCtransfersunderachangingfutureclimateallowingtheimportanceoffjordsasaclimateregulationservicetobereassessed.

10:00Testing theutilityof geochemical proxies forpaleoproductivity inoxic sedimentarymarinesettingsoftheGulfofAqaba,RedSeaZviSteiner1,2,BoazLazar1,AdiTorfstein1,3,JonathanErez1

1TheFredyandNadineHerrmannInstituteofEarthSciences,TheHebrewUniversity,Jerusalem91904,Israel2DepartmentofEarthSciences,UniversityofCambridge,CB23EQ,Cambridge,UK3TheInteruniversityInstituteforMarineSciences,Eilat88103,IsraelDuringtheearlystagesofsedimentdiagenesis,mostoftheorganicmatterreoxidizes,leavingbehinda small, potentially unrepresentative fraction of organic carbon. Paleo-productivity reconstructionstherefore identify changes in the chemical composition of carbonate shells or, when pristine onescannot be found, in the sedimentary content of inorganic elements associated with the originalorganicmatter.Toexaminetheapplicabilityofbulkinorganicelementscompositionforthistask,wecompare recorded changes in known anthropogenic nutrient fluxes to the oligotrophic andoxygenatedGulfofAqaba inthenorthRedSea,withthesedimentaryrecordsofbarium,cadmium,copperandnickeloverthelastdecades.Amongtheseelements,nickelandcopperstronglycorrelatewithrecordednutrientfluxesandprimaryproductivity intheregion. Inthepresentcase,nickel isamorereliableproxysincepartofthecopperispossiblycontributedfromair-bornepollutionsources.Theapplicabilityofcadmiumtoserveasa tracer fornutrientadditionscouldnotbereliably testedbecausecontributionofcadmiumassociatedwithphosphateoreloadingintheadjacentportsmaybesignificant. We do not observe any bulk sediment barium enrichments associated with increasednutrient fluxes. Overall, it appears from these correlations that nickel and probably also copperreliably record past changes in nutrient availability and organic matter fluxes while sedimentarybariumandbarite,whicharecommonlyattributedtoproductivity,donot.

10:15(30minuteKeynote)Icesheetstability:ApalaeoclimateperspectiveCarolineLear,CardiffUniversity TheimpactsofthegrowthanddecayofEarth’scontinentalicesheetsreachfarthroughouttheEarthSystem.Yet the local recordsof thesechangesareconstantly rewritten throughgeological time,sotheir history must be determined using indirect evidence. The oxygen isotopic composition offoraminiferareflectsboththechangingsalinityoftheoceanastheicesheetswaxedandwanedandalso the changing temperature of that ocean. Independent proxies such as the Mg/Ca-paleothermometer can be used to separate these two climate signals.What do such geochemicalproxy records tell us about ice sheet dynamics? First and foremost they demonstrate that thecryospheredoesnotrespondlinearlytoexternalforcingofEarth’sclimatesystem.Forexample,theestablishmentof theAntarctic ice sheetat theEocene-OligoceneTransition (~34Ma)was the rapidculminationofalong-termcoolingtrendthatbeganseveralmillionyearsearlier,asathresholdintheclimate systemwas passed. Defining the thresholds for ice sheet growth and decay is challengingbecause it integrates different aspects of the climate system, including radiative forcing andpaleogeography.Nevertheless,most ice sheetmodels agree that the climate threshold formeltingtheAntarcticicesheetishigher(warmer)thanforitsinception,duetothecold,elevatednatureofitsuppersurface.Thegeochemicalproxy recordsof theorbitally-paced icesheetgrowthanddecayatthe Oligocene-Miocene Boundary (~24 Ma) therefore present something of a geological puzzle,becauseatfirstsighttheyseemtocontainlittleevidenceofthishysteresiseffect.OnepossibleexplanationisthatthedeglaciationoftheAntarcticicesheetattheOligocene-MioceneBoundarywasfacilitatedbyaninputofcarbontotheocean-atmospheresystem.Inaddition,recentadvances in icesheetmodellingprovideabetter fit totheseproxyrecords.However, thesemodelshaveworryingimplicationsforfutureicesheetstability.Furtherworkisrequiredto(1)evaluatethesenewicesheetmodels,and(2)identifythepositivefeedbackprocessesthatcausedtheseimpressivedeglaciationeventsinthegeologicalrecord.

10:45

Persistent instability of glacial climate and overturning circulation in the NorthAtlanticforthepast1.5millionyearsD.A.Hodell1,P.C.Tzedakis2,L.C.Skinner1,M.Vautravers1,J.Rolfe1,J.Nicolson11GodwinLaboratoryforPalaeoclimateResearch,DepartmentofEarthSciences,UniversityofCambridge2DepartmentofGeography,UniversityCollegeLondon

Nick Shackleton’s pioneeringworkonpiston cores from the IberianMargindemonstrated that theplanktonic d18O signal resembles in great detail the temperature record of Greenland for the lastglacialcycle. In theabsenceofan icecoreolder thanthe last interglacial (~124ka) inGreenland,along sediment sequence from the IberianMargin could serve as a surrogate formillennial climatevariability(i.e.,Dansgaard-Oeschgerevents)intheNorthAtlanticduringtheQuaternary.Tothisend,wedrilledIODPSiteU1385(the“Shackletonsite”)ontheSWIberianMarginandrecovereda166.5-mcontinuoussectionthatextendsbackto~1.5millionyearsBP.Theagemodelisbasedonprecession-tuning of the colour record and is independent of oxygen isotope stratigraphy (i.e., LR04). Wemeasured stable isotopes of foraminifera continuously at 1- or 2-cm resolution corresponding to atemporal resolution of 100-200 years. The isotope record is used to evaluate how themagnitude,duration,andpacingofmillennialvariabilitychangedasglacialboundaryconditionsevolvedoverthelast1.5Ma,includingtheMiddlePleistoceneTransition(MPT).Millennial-scale variability has been a strong, persistent feature of surface climate on the IberianMargin during all glacial periods of the last 1.5 Ma. All millennial increases in planktic d18O aremirrored by decreases in benthic d13C, suggesting surface water cooling during stadials wasaccompaniedbychangesinAtlanticoverturningcirculation.Weobserveadiversearrayofmillennialvariabilitywithdifferingmagnitude,durationandpacingthroughoutthelatePleistocene.Duringthe“41-kyrworld”from1.5to1.25Ma,millennialvariabilitywasfrequentandpersistedthroughouteachglacialperiodwhenobliquitydroppedbelowthenearpresent-dayvalueof23.5o.Wesuggestthelinkbetweenincreasedmillennialvariabilityandlowobliquitymayberelatedtotheresponseofseaiceextenttointegratedsummerinsolation,whichshiftsthesourceareasofdeep-waterformationintheNorthAtlantic. After thestartof theMPTat1.25Ma,verystrongmillennialvariabilityoccurredateach of the glacial inceptions associated with declining obliquity, and at each of the glacialterminations associated with rising insolation. Millennial variability appears strongest when theearth’s climate system is transitioning intoandoutof a glacial state, reflectinganunstableAMOC.Althoughmuch of our concept of millennial variability is based on the Greenland ice core recordduringMIS3,thistypeofmillennialvariabilityinthemiddleofaglacialcycleisrelativelyuncommon.

11:15(aftercoffee,30minuteKeynote)

RosalindRickaby,UniversityofOxfordTheevolvingroleofphytoplanktoninthecarboncycle

11:45Relationofsortablesiltgrain-sizetodeep-seacurrentspeeds:Calibrationofthe‘MudCurrentMeter’

NickMcCave1,DavidThornalley2andIanHall3

1GodwinLaboratoryforPalaeoclimateResearch,DepartmentofEarthSciences,DowningStreet,CambridgeCB23EQ;2DeptofGeography,UniversityCollegeLondon,GowerStreet,London,WC1E6BT;3SchoolofEarthandOceanSciences,CardiffUniversity,Cardiff,CF103AT.

Fine grain-size parameters have been used for inference of palaeoflow speeds of near-bottom

currentsinthedeep-sea.Thebasicideastemsfromobservationsofvaryingsedimentsizeparameterson a continental margin with a gradient from slower flow speeds at shallower depths to faster atdeeper.Inthedeep-sea,size-sortingoccursduringdepositionafterbenthicstormresuspensionevents.Atflowspeedsbelow10-15cms-1meangrain-sizeintheterrigenousnon-cohesive‘sortablesilt’range(denotedby SS,meanof10-63μm) is controlledby selectivedeposition,whereasabove that rangeremovaloffinermaterialbywinnowingisalsoarguedtoplayarole.

AcalibrationoftheSS grain-sizeflowspeedproxybasedonsedimentsamplestakenadjacentto

sitesof long-termcurrentmeterssetwithin~100moftheseabedformorethanayearispresentedhere. Grain-size has been measured by either Sedigraph or Coulter Counter, in some cases both,betweenwhichthereisanexcellentcorrelationfor SS (r=0.96).Size-speeddataindicatecalibrationrelationships with an overall sensitivity of 1.36 ± 0.19 cm s-1/μm for Sedigraph (1.26± 0.18 Coultercounter). Acalibration linecomprising12points including9 fromthe Icelandoverflowregion iswelldefined, but at least two other smaller groups (Weddell/Scotia Sea and NW Atlantic continentalrise/Rockall Trough) are fittedby sub-parallel lineswith a smaller constant. This suggests a possibleinfluence of the calibre ofmaterial supplied to the site of deposition (not the initial source supply)which,ifdepletedinverycoarsesilt(31-63μm),wouldlimitSStosmallervaluesforagivenspeedthanwithabroadersize-spectrumsupply.Localcalibrations,oracore-topgrain-sizeand local flowspeed,arethusnecessarytoinferabsolutespeedsfromgrain-size.

Thetrendofthecalibrationsdivergesmarkedlyfromtheslopeofexperimentalcriticalerosion

anddepositionflowspeedsversusgrain-size,makingitunlikelythatthe SS (oranydepositsizeforthatmatter)issimplypredictedbythedepositionthreshold.Amoreprobablecontrolistherateofdepositionofthedifferentsizefractionsunderchangingflowsoverseveraltensofyears(thetypicalaveragingperiodof a centimetre of deposited sediment). This suggestion is supportedby a simpledepositionalmodel forwhich the deposited SS is calculated frommeasured currentswith a size-varyingdepositionalthreshold.Moresurficialsedimentsamplestakennearlong-termcurrentmetersites are needed to make calibrations more robust and explore regional differences. See doi:10.1016/j.dsr.2017.07.003

12:00Time-lapsebathymetricsurveysofanactivesubmarinevolcanoandimplicationsforhazardinthesouthernCaribbeanJ.S.Collier1,R.W.Allen1,C.Berry1,T.Henstock2,F.J-Y.Dondin3,J.L.Latchman3,R.E.A.Robertson3

1.DepartmentofEarthSciencesandEngineering,ImperialCollegeLondon,SW72AZ2.OceanandEarthScience,NationalOceanographyCentreSouthampton,SO143ZH3.TheUWISeismicResearchCentre,StAugustine,TrinidadandTobago Sincethefirstrecordederuption in1939,theKick-‘em-Jennyvolcano,8kmoffofthenorthcoastofGrenada,hasbeenthesourceof13notableepisodesofT-phaserecordings.Thesedistinctiveseismicsignals, often coincident with heightened local seismicity, have been interpreted as indicative ofextrusive eruptionswith amean recurrence interval of 5-6 years. However, direct confirmation ofvolcanismduringtheseepisodesisrare.ByconductingbathymetricsurveysfromtheRRSJamesCookin 2016 and 2017 (EM120 and EM710) and reprocessing 4 further legacy data sets spanningmorethan30yearsandseveralincidencesofT-phaserecordingsweareabletopresentaclearerpictureofthedevelopmentofthevolcanothroughtime.Thefinalbathymetricgridsproducedhaveacellsizeofjust5mand,forthemoremodernsurveys,averticalaccuracyontheorderof1-4m.Thesegridsshowthat T-phase episodes correlate with morphological changes at the volcano’s edifice. In the time-period of observation we document a clear construction deficit with 5 times more material lostthrough landslides and volcanic dome collapse than added through volcanic construction. Theapparent limited recent magma production means that the volcano may be susceptible to largereruptionswith longer repeat times than those covered in our study. These larger eruptionswouldclearlyposeamoresignificant localhazard than thesmall scalevolcaniceventsobserved in recentdecades.Thisbehaviorismoresimilartosomeofthesub-aerialvolcanoesinthearcthanpreviouslythought. Our results clearly demonstrate the capability of repeat swath bathymetry surveys as ameansofassessingsubmarinevolcanichazard.

12:15(30minuteKeynote)Theformationandevolutionofnewcrustatoceanridges:TacklingafundamentalEarthsciencechallengefrommultipledirections.Damon A.H. Teagle*, Peter B. Kelemen, Juerg Matter, Eiichi Takazawa, Katsuyoshi Michibayashi,JudithCoggon,MichelleHarris,JuanCarlosdeObeso,andtheOmanDrillingProjectPhase1ScienceParty* Ocean & Earth Science, National Oceanography Centre Southampton, University of Southampton, SO14-3ZH, UK.Damon.Teagle@southampton.ac.uk

Theformationofnewoceancrustatthemid-oceanridgesisthefoundationoftheplatetectoniccycleand the principal mechanism for the transfer of heat and mass from the Earth’s interior to thesurface.Sincetheinceptionofscientificoceandrilling,understandingmid-oceanridgeprocesseshasbeentheprimaryobjectiveofthe‘SolidEarth’,exemplifiedbynumerousoftheGrandChallengesinthecurrent IODPscienceplan (2013-2023). Althoughwehaveconceptualmodelsof theprocessesoccurring during the formation of the ocean ridges, there remains only poor knowledge of themechanisms and interplays betweenmagmatic accretion, tectonics, hydrothermal circulation. Basicconcepts such as the size and location of magma chambers or the depth and intensity ofhydrothermalexchangecontinuetobedebated.Thislackofknowledgeisprincipallyduetoalackofappropriatesamplesordirectobservations.Thisgreatlyhindersourabilitytoquantifytheimpactsofchangesinthemid-oceanridges,suchasspreadingratesorrelativelengthsoffastversusslowridges,onthebiochemicalbudgetsofmajorconstituentsofseawaterandmanyofthekeytracersweusetodeciphertheoperationofourplanet(e.g.,C,H2O,Mg,87Sr,18O).

Theremotenessoftheoceanridges,submergedbeneaththousandsofmetersofseawater,andtheirvast extent, requires multiple approaches to graft key observations, from oceanographic surveys,through marine geology, geophysics and modelling, to deep ocean drilling, to recovery of intactsamples in sterile conditions for study of subsurface microbial ecosystems.The ocean ridges havebeen inspirationaldriving forces for technologicaldevelopmentandnewscientificapproaches (e.g.,ROVs and AUVs, CSEM). Although remote observations and numericalmethods provide importantinsights, in situ samples are required to test concepts of magmatic accretion, crustal cooling, orhydrothermal exchange. This requires scientific ocean drilling through the exploitation of tectonicwindows or through the drilling of deep holes into intact ocean crust. This has proved extremelychallenging,especiallyfordeepholes,withpoorratesofcorerecovery,engineeringdifficulties,andcareer-durationexperiments.

Studies of ridge processes at sea have always been complemented by onshore investigation ofophiolites.Although it isapparentthatophiolitesarenot identicaltoPacificOceancrust,studiesofobductedblocksofcrustanduppermantleformedatspreadingridgeshaveformedavitaltouchstoneusedforinterpretinggeophysicaldataandsparsesamplesfromdredginganddrillinginthecontextofidealizedcrustalsectionsandhypothesesaboutalong-strikevariation.Inarecent,ambitiousexampleof this dialectical relationship, a significant proportion of the ocean ridge community is currentlyfocusedon theSamailophiolite inOman, the largest andbestexposed sliceofocean crust and itsunderlyingmantlepreservedon-land.

Phase1oftheICDPOmanDrillingProjecthasjustended,with1500mofdiamonddrillholerecoveredfrom the lower crust andmantle of the Samail ophiolite,with scientific ocean drilling quality corecharacterisationhavingjustbeencompletedaboardtheD/VChikyu.Thecombinationofexcellent3-dimensional exposures, decades of meticulous field geology, wireline geophysical logs, and 100%

rates of core recovery provides exceptional new opportunities to understand and quantify theprocesses operating in ophiolites and the ocean ridges. New facilities such as continuous X-raytomography,corescanningXRF,andnearvisibleinfraredscanningavailableaboardChikyuhavebeenused at scale for the first time and enable objective quantification of features to complementtraditional visual core description, sampling and analysis. The huge amount of data generated bythese new techniques necessitates new machine learning approaches of data analysis andverification. TheOmanDrilling Project observations provide a unique opportunity to quantitativelyintegrate drill cores, wireline logs, and outcrop observations, and master techniques for futuredeploymentinscientificoceandrilling.

13:45(afterlunch,30minuteKeynote)

TheSouthAtlanticTransectdrillingproject,multi-disciplinarycollaborationsinmarinescience.RosalindM.Coggon,RobertS.Reece,GailL.Christeson,MarkLeckie,BrandiKielReese,DamonA.H.Teagle,WilliamP.GilhoolyIII,JasonSylvan,NicholasW.Hayman,JamesZachos,BrandonR.Briggs,CliffordHeil,MatthewHuber,JuliaS.Reece,SvenjaRausch,JohnKirkpatrick,MichelleHarris,DebbieThomas,MiriamKatz,ChristopherLoweryDeepSeaDrillingProject Leg3drilleda transectof sedimentholesacross thewestern flankof thesouthernMid-AtlanticRidgetodemonstratethatthebasalsedimentageincreasedwithdistancefromtheridge,provingthetheoriesofseafloorspreadingandplatetectonics.DuringLeg3thesedimentswere only spot-cored, but revealed moderate to excellent preservation of the CaCO3 microfossilsrequiredtogeneratehigh-fidelityproxydataforpaleoceanographicreconstructions.Givendramaticadvances in drilling technology and analytical capabilities since Leg 3,many high priority scientificobjectives could be addressed by revisiting the Leg 3 transect. We therefore proposed amultidisciplinary IODP transect through the Leg 3 area at ~31 °S, to recover complete sedimentsectionsandtheupper150-250mof7,15,31,48and63Maoceancrust.Theproposal(IODP853Full-2)receivedexcellentreviewsandhasbeenrecommendedforscheduling,withthedrillshipexpectedtooperateintheAtlanticin2020.Theproposedtransectfollowsacrustalflow-linefromtheslow/intermediate-spreadingMid-AtlanticRidgeandwill fill criticalgaps inoursamplingof intact in-situoceancrustwithregardscrustalage,spreading rate, and sediment thickness, required to investigate the low-temperature hydrothermalagingofoceancrust.Thetransectalsotraversesthehithertounexploredsediment-andbasalt-hosteddeep biosphere beneath the South Atlantic gyre, and is located near World Ocean CirculationExperiment (WOCE) line A10, providing access to records of carbonate chemistry and deep-watermassproperties(e.g., temperatureandcomposition)acrossthewesternSouthAtlanticthroughkeyCenozoic intervals of elevated atmospheric CO2 and rapid climate change. The proposed transectthereforeprovidesawealthofopportunitiesformulti-disciplinarycollaborationsinmarinescience.

14:15DevelopmentofalargesedimentdriftnearthemouthofMargueriteTrough,

AntarcticPeninsulaasarecordofpasticestreamdynamics

Robert D. Larter1, Alastair G.C. Graham2, Claus-Dieter Hillenbrand1, Kelly A. Hogan1, F. JavierHernandez-Molina3,JamesE.T.Channell4,ChuangXuan5,DavidA.Hodell6,MariaC.Williams1,SimonJ. Crowhurst6, KarstenGohl7,MicheleRebesco8,GabrieleUenzelmann-Neben7 andRRS JamesClarkRosscruiseJR298ScientificParty.1BritishAntarcticSurvey,HighCross,MadingleyRoad,CambridgeCB30ET,UK(email:rdla@bas.ac.uk);2CollegeofLifeandEnvironmentalSciences,UniversityofExeter,ExeterEX44RJ,UK;3DepartmentofEarthSciences,RoyalHollowayUniversityLondon,Egham,SurreyTW200EX,UK;4DepartmentofGeologicalSciences,UniversityofFlorida,Gainesville,Florida32611,USA;5SchoolofOceanandEarthScience,UniversityofSouthampton,SouthamptonSO143ZH,UK;6DepartmentofEarthSciences,UniversityofCambridge,DowningStreet,CambridgeCB23EQ,UK;7AlfredWegenerInstitute,Helmholtz-CentreforPolarandMarineResearch,Bremerhaven,Germany;8IstitutoNazionalediOceanografiaediGeofisicaSperimentale(OGS),Sgonico(TS)Italy.LargesedimentdriftsonthecontinentalrisewestoftheAntarcticPeninsulahavedevelopedsincethemiddle Miocene and contain continuous, high-resolution records of ice sheet and oceanographicchange.Newhigh-resolutionmultichannelseismicdata,multibeamechosoundingdataandacousticsub-bottomprofileswerecollectedaroundproposeddrillsitesonseveraldifferentdriftsduringRRSJamesClarkRosscruiseJR298inJanuary–February2015.Sevenpistoncoreswerealsocollected,allbutoneofwhichwere from locations close to theproposeddrill sites. In thispresentationwewillfocus on results fromDrift 5, which is located close to themouth ofMarguerite Trough and thusideallylocatedtorecorddynamicchangesinthemajoricestreamthatflowedalongthetroughduringQuaternaryglacialmaxima.TheproposeddrillsiteonthecrestofDrift5is30kmfromtheshelfedgeat themouth of the trough. In the Pliocene themouth ofMarguerite Troughwas located furthersouthalongthemargin,andmigrationofthetroughtoitspresentpositioninfluenceddevelopmentandmorphologyofthedrift.Nine new multichannel seismic lines covering 580 line-km were collected over Drift 5 and thesurrounding area, providing an unprecedented opportunity to examine its internal structure anddevelopment.Thedataconfirmaverysimple‘layercake’stratigraphybeneaththecrestofthedrift,showingcontinuous,parallelreflectorswithaverygentleseawarddipthatextendtowithin25kmofthe continental shelf edge. Connections to sparse older seismic lines allow age control to beestablishedbycorrelationtoODPLeg178sitesandDSDPSite325.Thenewmultibeamechosoundingdatacombinedwithpreviousdatanowprovidecompletecoverageofthedriftandrevealevidenceofextensivemasswastingon its flanks.Acoustic sub-bottomprofiler data collected along the seismiclinesshowevidenceoflocalisedfluidescapestructuresthatarelikelypathwaysforexpulsionoffluidsreleasedbysilicadiagenesisatdepth.A9.4m-longpistoncorerecoveredat2647mwaterdepthnearaproposeddrillsiteonthecrestofthedriftdidnotpenetrateintoMarineIsotopeStage5.Ina12.9m-longpistoncorerecoveredat3000mwaterdepthonthecrestofthedriftfurtherawayfromthecontinental slope,Marine Isotope Stage5.5 is identifiednear thebaseof the corebelow11mbsf,indicatinganaveragesedimentationrateof>9cm/kyrthroughthelastglacialcycle.WeconcludethatadrillsiteonthecrestofDrift5hasthepotentialtoprovideanexpanded,continuousrecordofpastdynamicsoftheMargueriteTroughpalaeo-icestream.

14:30ThestratigraphicincompletenessofsubmarinechannelsdepositsVendettuoli,D1*.,Clare,M.2,Cartigny,M.3,Hage,S3,HughesClarke4,J.,Talling,P.3,Vellinga1,A.,Waltham,D.51UniversityofSouthampton,SchoolofOceanandEarthScience,UK2NationalOceanographyCentre,MarineGeoscience,UK3DurhamUniversity,DepartmentofGeography,UK4CenterforCoastalandOceanMapping,UniversityofNewHampshire,USA5RoyalHollowayUniversityofLondon,UK

Turbidity currents transport prodigious quantities of sediment across the world’s oceans throughsubmarine channels, deposit major oil and gas reservoirs within submarine fans and damagestrategically important seafloor infrastructure. We therefore need to understand these flows, buttheir verypowerfulnaturemakesdirectmonitoring challenging.Most studies todate focuson thedeposits that turbidity currents leave behind in the sedimentological record. However, deposits ofindividual flow are likely to be reworked, particularly in the proximal part of submarine channelswhere supercritical flows dominate. This leaves us with the questions: How complete is thestratigraphy of these deposits? Are some events better preserved than others? Quantifyingstratigraphiccompleteness,andhowitvariesoverdifferenttemporalandspatialscales,iscrucialtounderstand howwell deposits can be used in quantifying turbidite frequency, identifying the bestlocationsforreconstructingpalaeoenvironments,andtounravelpastsedimentbudgets.Weaddressthesequestionsbyre-analysingthemostdetailedtime-lapsemappingyetofasubmarineturbidity current system. This field dataset comes from the fjord-head Squamish Delta in BritishColumbia,CanadawhereHughesClarke(2016)collected93near-dailyrepeatsurveysin2011.Thesesurveys revealed the seafloor response to more than 100 turbidity currents. Three channels areidentified (northern, central and southern) that initiate fromadelta-lip andextend todepositionallobesatapproximately150mwaterdepth.Thus,ahighlyactivesystemcanbestudiedfromsourcetolobeinacompactarea.Hereweusetemporalchangesinseabedelevationtounderstandpatternsofdepositionanderosion(andthusdepositstratigraphy)ateachpointduringthese100successiveflows.Wecalculatethetotalthickness of sediment deposited at each location, and the percentage of this sediment that ispreserved (the stratigraphic completeness). Erosion by subsequent flowsmay substantially reducestratigraphic completeness, and the majority of initial deposits are reworked by later flows. Theaverage stratigraphic completeness near to the three channels is <1%, but this is highly spatiallyvariable,as some levees recordup to40%completeness.This lowvalue is largelydue toupstreammigratingbedformsthatconstantlyreworkpreviouslyemplacedsediments.Threedifferentpatternsarefoundinthethreechannels.Thenorthernchannelshowsadisproportionatepreservation(upto60%)of limitedrun-out,but largedelta-lip failures in itsuppercourse (duetotheirpluggingeffect,whichdriveminoravulsions).Thecentralchannelismainlyerosionalinitsproximalpart,andhaslittlepreservationofdeposits in the lowerchannel.The southernchannel isdominatedbyerosion,withnet-erosion due to meander bend incision, and at the channel lobe transition zone. Perhapssurprisingly,evenattheterminallobes,stratigraphiccompletenessistypically<5%;especiallyclosetothechannelmouths.Theseresultsprovidenewinsightsintotheevolutionofsubmarinechannelsandwhytheirdepositsproduceahighlyincompleterecordofsubmarineflows.

14:45(30minuteKeynote)ABGSforwardlookatMarineGeoscienceintheUK:PrioritiesinatimeofchangeRobertGatliff,DirectorMarineGeoscience,BritishGeologicalSurvey,TheLyellCentre,ResearchAvenueSouth,Edinburgh,EH144APTheMarineGeologicalSurvey in theUKbegan in1966 in responseto thenewoffshoreoilandgasindustry. TheGovernment funded amajor nationalmapping programme (including high-resolutionshallow seismic,magnetic and gravity data, a series of boreholes, gravity cores etc.). By 1992, theshelfareaswereallmappedat1:250,000scale(seabedsediments,Quaternaryandbedrock).Thefinaloffshoreregionalreport(Rockall)waspublishedin2013followinganextensivecollaborativeresearchprogrammewithindustrycoveringtheAtlanticMargin.Establishedskillsetsandextensiveexperienceinmarine operations and engineering has since enabledBGS to lead the EuropeanConsortium forOceanResearchDrillingoperations.Increasingdemandformoredetailedevidencetomeettherequirementsoftheoffshorerenewablesindustry, aggregates extraction, decommissioning, fishing, aquaculture and meeting EUenvironmentalDirectivesandthedevelopmentofanetworkofmarineprotectedareashasledtothegradual development ofmore detailedmaps andmodels based on new seismic and in particular,multibeam data. Excellent collaboration between different parts of Government has led to freelyavailablemultibeamdatatounderpinanewgenerationofgeological,geomorphologicalandhabitatinterpretations.AlthoughtheUKstillonlyhasaround30%coverageofmultibeamdata,thecoveragegrowsannually,primarily through theCivilHydrographyProgramme,but supportedbymanyothersources, includingdatacollectedbytheBGSsmall surveyvessel, theWhiteRibbon.Manycountriesnow have national mapping programmes based onmultibeam data (e.g. INFOMAR in Ireland andMareanoinNorway)andtheUK’sunderstandingof itsownterritorialwaters isnowlaggingbehindmanyinEurope.Todaytherearenewchallengestoanswer:Can we really manage our seas effectively with almost 70% of the UK seabed not mapped usingmodernmethods?What is happening at our coasts? Dowe needmore detailed onshore-offshoremodels across thecoast to answer questions about rates of erosion, amounts and changes in sediment budgets, andwhatwecandotomitigatethe impactsofsea levelrise?Thehistoryofsea levelrisesincethe lastglaciation recorded in seabed geomorphology demonstrates the complex nature of erosion ratesduringthelast10,000yearsandguidesourmodelsforfuturechangesatthecoast.Can wemaximise the effective development of marine renewable energy? The results of the lastglacial advance and retreat are fundamental to the offshore renewables industry and a betterunderstandingof relatedprocessesandengineeringpropertiesof the shallowoffshoregeologyarecriticaltotheinstallationandmaintenanceofouroffshorerenewableenergycapacity.DidtheStoreggaslidegeneratethelastlargetsunamitohittheUK?Whatisthepotentialforlocallyderivedtsunamis(fromclifffalls;nearshorelandslidesetc.),orfar-fieldtsunamidamagearoundtheUKcoasts?Howwillourmarineecosystemsevolvewithclimateandrespondtodevelopmentpressures?Can we develop the deep-sea mining industry? Nodules, crusts and massive sulphides are majortargets fornewmining.Oresarehighgrade. Is theUKbeing leftbehind? Autonomousandrobotictechnologiesforenvironmentalmonitoring,explorationandproductioncouldputtheUKintheleadacrossanewlydevelopingsupplychain.

15:30(aftercoffeebreak)

Howcanweuseemergingtechnologytodirectlymeasurepowerfulanddamagingdeep-seageohazards?Clare,M.A.*1,Vardy,M.E.1,Cartigny,M.J.B.2,Talling,P.J.2,Himsworth,M.D.3,Dix,J.K.4,Harris,J.M.5,Whitehouse,R.J.S.5,Belal,M.31) National Oceanography Centre, University of SouthamptonWaterfront Campus, EuropeanWay,Southampton,SO143ZH,UK;2)DepartmentsofEarthScienceandGeography,UniversityofDurham,Durham,DH13LE,UK;3)SchoolofPhysicsandAstronomy,UniversityofSouthampton,Highfield,Southampton,SO171BJ,UK;4) School of Ocean and Earth Science, University of Southampton, National Oceanography Centre,SouthamptonSO143ZH,UK;5)HRWallingford,HowberyPark,Wallingford,Oxfordshire,OX108BA,UK.Seafloor networks of cables, pipelines and other infrastructure underpin our daily lives, providingcommunication links, information and energy supplies. Despite their global importance, thesenetworks are vulnerable to damage by a number of natural seafloor hazards, including landslides,turbiditycurrents,fluidflowandscour.Conventionalgeophysicaltechniques,suchashigh-resolutionreflection seismic and side scan sonar are commonly employed in geohazard assessments. Theseconventionaltoolsprovideessentialinformationforrouteplanninganddesign,howeversuchsurveysprovideonlyindirectevidenceofpastprocessesanddonotobserveormeasurethegeohazarditself.Assuch,manynumerical-basedimpactmodelslackfield-scalecalibrationandmuchuncertaintyexistsaboutthetriggers,natureandfrequencyofdeep-watergeohazards.Recentadvances intechnologynow enable a step-change in their understanding through direct monitoring. We outline someemerging monitoring tools and how they can quantify key parameters for deep-water geohazardassessment.Repeatseafloorsurveysindynamicareasshowthatsolelyrelyingonevidencefrompastdepositscanleadtoanunder-representationofgeohazardevents.AcousticDopplercurrentprofilingprovides new insights into the structure of turbidity currents; while instrumented mobile sensorsrecord thenatureofmovementat thebaseof those flows for the first time. Existing andbespokecabled networks enable high bandwidth, low power and distributedmeasurements of parameterssuchasstrainacross largeareasofseafloor.Thesetechniquesprovidevaluablenewmeasurementswhich will improve geohazard assessments, and should be deployed in a complementary manneralongsideconventionalgeophysicaltools.

15:45

3DSeismicData:Past(Exploration),Present(ExplorationandGeohazards)andFuture(Exploration,GeohazardsandDecommissioning)E.SelfandK.PGamesGardlineGeosurveyLtdIntheearlyyearsoftheOffshoreOilandGasIndustry,theexplorationdatawereall2D,acquiredbytowingone streamer andone source alongevery sail line.Datawere acquiredwith closely spacedlinesbuteven thedensestof thesewereof theorderofhundredsofmetresapart.With such linespacing,manygeologicalfeaturesarespatiallyaliased.Thentheabilitytoshootandprocess3Dwasdeveloped,with the first 3D commercial dataset being acquired in theNorth Sea in 1975. The 3Dtechnique reduces the onset of aliasing by at least an order of magnitude. The industry rapidlyimprovedtheacquisitionofsuch3Ddatabytheuseofcloselyspaced(typically25m)multi-streamersystems(12streamersupto10kminlengthsoonbecamethenorm),andthisenabledlargeareastobecoveredinrelativelyshorttime.Everincreasingimprovementsinbothacquisitionandprocessinghave ledtogreatlyenhanceddatasets,andthesedataaregridded into ‘bins’duringtheprocessingstage,withtypicalbinsizesof12.5mx12.5m.However,theuseofthesedatasetsintheevaluationofgeohazardshasalwaysbeenvery limited,mainlyduetothe lackofverticalresolutionofsuchdata.Thisisessentiallyduetothefrequencycontentofthedataandtheacquisitiongeometry,andwhilethese canbeenhanced to improve the resolution, inmany cases theywill alwaysmean that thesedatasetscannotbeusedtoprovidetherequiredgeohazardassessment.Thisgeohazardanalysiswasnormally carried out using High Resolution Seismic (HRS) 2D data. However, recent developmentshave led to the introduction of HRS 3D data acquisition, with typical bin sizes of 6.25mx6.25m orsmaller, and this is now being used as the optimum technique for complex areas of geohazardproblems.WiththeOilandGasIndustrynowenteringanewphasewheredecommissioningofmajorfieldsisstartingtohappen,thisnewHRS3Dtechniquehasgreatpotentialforresolvingsomeoftheissuescomingtotheforeinthedecommissioningphase.

16:00(30minuteKeynote)Marineroboticsandtheirpast,presentandfutureapplicationsformarinegeoscienceProfRussellBWynnChiefScientist,MARS(MarineAutonomousandRoboticSystems)NationalOceanographyCentre,EuropeanWay,Southampton,SO143ZHMarineroboticvehicleshavebeenusedinmarinegeoscienceresearchforovertwodecades,butthenumberofdeploymentsandrangeofapplicationshavebothrapidlyincreasedinrecentyears.Marinegeoscience applications are primarily focussed on seabedmapping and imaging, using high-power,short-range, propeller-driven autonomous underwater vehicles (AUVs) or physically tetheredremotely operated vehicles (ROVs). However, new unmanned surface vehicles, capable of carryingmultibeamsonars, and low-power, long-rangeAUVsareopeningupnewpossibilities for scientists.This presentation will provide a series of case studies illustrating past and present applications ofmarine robotics for marine geoscience, based upon the UK National Marine Facilities – MarineAutonomousandRoboticSystemsfleet(seephotobelow),andwillconcludewithalookatpotentialfutureapplicationsbaseduponnewtechnologicalinnovations.

Reference Wynn, R.B., Huvenne, V.A.I., Le Bas, T.P., Murton, B.J., Connelly, D.P., Bett, B.J., Ruhl, H.A., Morris, K.J., Peakall, J., Parsons, D.R., Sumner, E.J., Darby, S.E., Dorrell, R.M. and Hunt, J.E. (2014) Autonomous Underwater Vehicles (AUVs): their past, present and future contributions to the advancement of marine geoscience. Marine Geology, 352, 451-468 (50th Anniversary Special Issue).

16:30

TheriseofinternationalcollaborationsinUKmarinesciencefrompublicationco-authorshipsNeilC.MitchellSchoolofEarthandEnvironmentalSciencesUniversityofManchesterManchester,M139PLU.K.The numbers of co-authored research articles provide a record of the history of internationalcollaborations. In thisstudy,articles inmarinesciencewithco-authorsbased in theUKand inoneothercountry(theUSA,Germany,France,ItalyorSpain)wereextractedfromtheWebofScienceTM.To overcome problems with keyword searches, the study used journal names to indicate marinesciencesubjectmatter.Althoughthesearchmaynotfullyrevealabsolutenumbersofmarinesciencearticles,interestingtrendsarefound.Whereas thenumber ofUKpublications inmarine science increased steadily from the early 1970swithadoublingtimeof16years,thosewithco-authorsbasedintheUSAincreasedwithadoublingtimeofonly8yearsonaverageuntil1997.Theythenabruptlymorethandoubledinonlyoneyearandsubsequentlycontinuedtorise,thoughwithasloweracceleration(doublingtime11years).Thispatternofearlyrapidlyacceleratingrise,abruptincreaseandsubsequentmoremodestaccelerationisseen in articles co-authoredwith researchers from France, Germany, Spain and Italy, thoughwithdelaysintheabruptincreasestagebyuptoafewyearscomparedwiththeUSAco-authoredarticles.European funding has likely been important for promoting collaborations and the numbers ofEuropeanco-authoredpapersaregreaterthanthosewithUSA-basedco-authorsbyanamountthatisindeedhigherthanwouldbeexpectedfromthesizesofthecountrypopulations.

AbstractsforPosterPresentations

Theversatilityofpetrophysicaldatatohelpoceandrillingresearch

LeBer,E.,Inwood,J.,Morgan,S.,Phillpot,L.,Davies,S.UniversityofLeicester,UK.

Since the late 1980s, petrophysicists from theUniversity of Leicester havebeen involved in

offshore scientific coring projects, mostly sailing with the International Ocean Discovery Program(IODP) and its predecessors. Each IODP expedition aims to address different scientific objectives,covering themes including climate and sea level change, geohazards, deep biosphere and earthdynamics.ResearchundertakenbyLeicesterpetrophysicistsusesinsitudatacollecteddownholeandphysical propertiesmeasurements from subseafloor core samples. Commonly this work is done incollaborationwithotherinternationalresearchersinvolvedintheexpeditions.

Petrophysicaldataareacrucialsourceofinformation:theyprovideinsighttoawiderangeof

geoscientific fields. They have been used to contribute making the link between geology andgeophysics (IODP Expeditions 325, 340, 352), an important step in offshore environments whereseismicdatacoverwideareas.Standardmeasurementsinholesandonrecoveredcoresalsofacilitatecorrelationsbetweenmultipleholesatonesite,orbetweensitesacrossaregion.Downholelogginghasalsoproventobeextremelyusefulasasourceofinsituinformation,notablyimagestoevaluatethequalityoftheformationandborehole(IODPExpeditions310,343).Petrophysicsgeneratesalotofdata, and the group at Leicester frequently uses cluster analysis as a tool to help with theinterpretationoflithologiesandinintervalswithlowcorerecovery(IODPExpeditions310,313,325).Ongoingandfutureresearchalsousesclusteranalyseson images(high-resolutiondigital linescans),andcoreanddownholepetrophysicaldatatoidentifychangesinsediment/rockfacies/textures(IODPExpeditions 364, 381). A workflow is being created to perform similar studies with datasets fromotherexpeditions*.

*IODP expeditions are international scientific collaborations that use research platforms to

explorerocksandsedimentsfromthesubseafloor.Expeditions:

310-TahitiSeaLevel313-NewJerseyShallowShelf325-GreatBarrierReefEnvironmentalChanges340-LesserAntillesVolcanismandLandslides343-JapanTrenchFastDrillingProject(JFAST)352-Izu-Bonin-MarianaForeArc364-ChicxulubK-PgImpactCrater381-CorinthActiveRiftDevelopment

GeomorphometricCharacterisationofSeabedFeaturesUsingaGIS-basedSemi-automatedToolbox

JoanaGafeira1,DiegoDiaz-Doce1,LaurenceH.DeClippele2,RobertGatliff1

1-BritishGeologicalSurvey,LyellCentre,Edinburgh,EH144AP2-CentreofMarineBiodiversityandBiotechnology,SchoolofLifeSciences,Heriot-WattUniversity,Edinburgh,EH147AYMarinegeologicalmappingmethodshaveevolvedsubstantiallyoverrecentdecades,alongwiththediversificationoftheusesforthismapping.However,manualmappingofseabedfeaturescanstillbeanenormouslytime-consumingandsubjectivecomponentoftheefforttomapandunderstandtheseabedgeology.ToaddressthattheBritishGeologicalSurveydevelopedasemi-automatedmappingtoolbox. This ArcGIS-based “BGS Seabed Mapping Toolbox” recognises, spatially delineates andmorphometricallydescribesseabedfeatures includingpockmarks,coralmoundsandotherconfinedfeatures.Since it was first developed, several thousand pockmarks have already been mapped andcharacterisedaroundtheUKcontinentalshelf,especially,withinthecentralNorthSea(Gafeiraetal.,2012). Ithasalso recentlybeenapplied toothergeographicareas (BarentsSea,NorwayandMalinDeep,Ireland)withvariedpockmarkandseabedmorphology,andindifferentgeologicalsettings.Thissystematic and consistent characterization of such vast numbers of pockmarks, with multiplemorphological characteristics, allows an unprecedented statistical analysis of their morphology.Combining this with the geological and oceanographical knowledge of individual areas providesinsights into the processes responsible for their development and the influence of local seabedconditions.This toolboxwasalsousedtosemi-automaticallydelineateover500Lophelia reef ‘mini-mounds’ intheMingulayReef.Themorphologicalcharacterizationextractedwascombinedwithdata fromtheROV-basedmicrobathymetry. This allowed the creationof predictionmaps of the likelihoodof thepresenceof live cold-water coral colonies in individual coralmounds (DeClippeleet al.,2017) andimprovedtheunderstandingofthefactorsthatcontrolthedistributionoftheseecosystems.Thesearejustsomeexamplesofpotentialoftheuseofobjectivesemi-automatedmethodsofseabedmappingandquantitativecharacterizationoftheseabedfeatures.

Howdoesmarinesedimentarymicrobialsulfatereductiondrivecalciumcarbonatepolymorphism?

ChinVikLin1*,AlexandraV.Turchyn1,ZvikaSteiner1,PieterBots2,GiulioI.Lampronti1,NicholasJ.Tosca3

1DepartmentofEarthSciences,UniversityofCambridge,CambridgeCB23EQ,UnitedKingdom.2DepartmentofCivilandEnvironmentalEngineering,UniversityofStrathclyde,GlasgoG11XJ,UnitedKingdom.3DepartmentofEarthScinces,UniversityofOxford,SouthParksRoad,OxfordOX13AN,UnitedKingdom.(*correspondence:cyl48@cam.ac.uk;chinyik85@gmail.com)

Microbial sulfate reduction, coupled either to organic matter oxidation or anaerobic methaneoxidation,maybeoneof thekeydriversof sedimentaryauthigenic carbonate formation inmarinesediments, intertidalmarshesandhypersaline lakes.Whilemuchworkhasbeendoneexploringtheprecipitation of different carbonate polymorphs in abiotic conditions, less is known about thedifferent carbonate polymorphs produced during microbial biomineralization driven by microbialsulfate reduction. In this study, we grow sulfate reducing bacteria (D. bizertensis) in media withvaryingMg/Caandseedingmaterials(calciteandkaolinite).Ourresultssuggestthatsulfatereducingbacteria induce carbonate precipitation and serve as a nucleation for the growing carbonate; themajorityofourcarbonatewasfoundgrewoncellmaterialratherthanthemineralseeds.WealsofindtheMg/Caratioandphosphateinthemediaplaysakeyroleincontrollinghowquicklycarbonateisproduced andwhich polymorph grows. Inmedia where theMg/Ca is greater than 2, a crystallinemonohydrocalcite is the primary carbonatemineral produced.We convertedmonohydrocalcite toeithercalciteoraragoniteabioticallyattheendoftheincubation.Althoughphosphateconcentrationshave a lesser effect on which polymorph initially precipitates, the presence stabilizesmonohydrocalcitecrystalsandpreventstheirtransformationtomorestablepolymorphs.Thisstudysuggests that calcium carbonate cements precipitated through microbial sulfate reduction isdeterminedbythesolutionchemistryatthetimewhennucleationstarted.

ChallengerRevisited:IlluminatingAnthropogenicClimateChangeWith150YearsOfOceanScienceLyndseyFox*,TomHill,StephenStukinsDepartmentofEarthSciences,TheNaturalHistoryMuseum,London,SW75BD,UK*Lyndsey.Fox@nhm.ac.ukWidelyregardedasanimminentthreattoouroceans,OceanAcidification(OA)hasbeendocumentedinalloceanicbasins.Bothmeasuredandprojectedchanges in seawater chemistryhavepotentiallycatastrophic biotic effects as OA hinders biogenic carbonate production, leading to substantialchanges inmarine ecosystems. Current attempts to address this issue via laboratorybased studieshaveserious limitations,whichcanonlybeovercomebyexploitingnewlydiscoveredplanktontowsfrom the historic HMS Challenger expedition (1872-1876) and ground-breaking TARA expeditions(2009-2016).Thisprojectwill investigatethebiologicaleffectsandrevealtheimpactandmagnitudeofOAacrosstheglobe.

Changesinpalaeodeep-wateroxygenconcentrationsalongtheIberianMarginacrosstheMid-PleistoceneTransitionusingabenthicd13Cproxy.NicolaThomasandDavidA.HodellGodwinLaboratoryforPalaeoclimateResearch,DepartmentofEarthSciences,UniversityofCambridge,DowningStreet,CambridgeCB23EQDeconvolutionofthebenthicd18OsignalatSite1123intoitstemperatureandseawatercomponentssuggestsanabruptincreaseinglacialicevolumeoccurredat900ka(MIS24-22)duringtheMPT.Atthesametime,neodymiumandcarbonisotopicevidencesuggestsamajorchangeoccurredindeep-water circulation. Benthic d13C values are among the lowest at many sites during MIS 22-24,suggestingincreasedcarbonstorageinthedeepsea.ThisshouldhaveaffectedatmosphericCO2andindeedlowervaluesofglacialCO2havebeenobservedafter900ka.To study the changes in nutrient regeneration and apparent oxygen utilization across theMPTweused a recently calibrated stoichiometric proxy for palaeooxygen based on the carbon isotopegradient between epifaunal Cibicidoidies wuellerstorfi and infaunal Globobulimina affinis on theIberianMargin(Hooggakkeretal.,2015).Wehavethusfarmeasuredd13CofthesetwospeciesatSiteU1385(“Shackletonsite”)fromMIS30to22. Sharpdecreases inthed13Cgradientareobservedatterminations26/25,24/23andthroughoutmuchofMIS22suggestingoxygenconcentrationsasalowas 135 mmol kg-1, similar to values obtained for values observed during some Heinrich events(Hooggakkeretal.,2015).Furtherworkisneededtoassesswhethertherewasastepchangeinglacialdeep-seaoxygenconcentrationsat900ka.

AnatomyoftheoldestknownHeinricheventsinMIS16atSiteIODP1308AbbieP.B.Currington,MarylineJ.Mleneck-Vautravers,David,A.Hodell

GodwinLaboratoryforPalaeoclimateResearch,DepartmentofEarthSciences,UniversityofCambridge,DowningStreet,CambridgeCB23EQ

MarineIsotopeStage(MIS)16representsoneofthelargestglaciationsoftheQuaternary,consistingoftheDonianglaciationinEurope.ItalsomarksthestartofdynamicbehaviouroftheLaurentideIceSheet throughHudsonStraitexpressed inNorthAtlantic sedimentsasHeinrich layers. We studiedIODPSiteU1308(re-occupationofSite609) inthecentralNorthAtlantic todocumentthefirst tworecordedHeinricheventsthatoccurredneartheendofMIS16.SimilartoHeinricheventsofthelastglacialperiod,H16.1and16.2aremarkedbyrazor-sharpbases,abundantdetritalcarbonategrains,andlowabundanceofplanktonicforaminifers.However,planktonicforaminiferalassemblageswerenoticeablywarmer duringH16.1 and 16.2 than those of their last glacial counterparts and containrare,butwell-preserved,temperateforaminifera(G.bulloides&G.inflata).BetweenH16.2 and 16.1, two distinctive silicate-rich peaks of IRD are recorded consisting ofwell-roundedgrainsofdiverselithologyinthecoarsestsedimentfraction(>1mm),perhapsreflectingiceincorporation in coastal region. Quartz dominates in the finer sediment fractions. Although thesourceoftheseIRDeventsawaitscompletionofSrandNdisotopeanalysis,theymaybederivedfrommultiple ice sheets and contain substantial contributions from Eurasia. The older event postdatesH16.2andtheyoungerpredatesH16.1withaperiodofhighcarbonatecontentandlowIRDbetweenthesilicate-richIRDpeaks.The silicate-rich events appear to be closely related to H16.1 and 16.2 although the older eventpostdatesH16.2whereastheyoungereventpredatesH16.1.Theyarenotassimpleastheprecursorevents proposed for last glacial Heinrich events, whereby instability of European ice sheets weresuggested as a trigger for Heinrich events. Increased roundness of coarser grains in the silica-richevents, andpotentialbetter sorting, suggestnotonly that theseeventsoriginated fromadifferentsourcethantheHeinrichevents,butthatsea-icemayhaveplayedarole inthetransportof IRD, inadditiontoice-bergs.

Marineoperations:geologythroughtechnologyJosephHotherall,WillLewis,BobGatliffBritishGeologicalSurveyThe BGS Marine Operations department, designs, builds and operates a suite of remote subseasamplingsystems.Thesehaveseenuseonawiderangeofresearchprojectsrangingfromdeepseadrilling intohydrothermalsystemstothemappingofthe lastBritishandIrish Icesheet.Theyrangefrom the RD2 seabed rock drill capable of drilling, coring, logging and sealing boreholes in waterdepthsupto4000mtotheshallowwaterWhiteRibbonsurveyvessel.

Please note there will also be several industry posterpresentations from Geotek and GESAMP and we are awaitingseveralmoreposterabstractsasofthisprinting.