Discovering Earth's Hidden Frontiers through Scientific Ocean Drilling
58
pages
English
Documents
2012
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
58
pages
English
Documents
2012
Le téléchargement nécessite un accès à la bibliothèque YouScribe Tout savoir sur nos offres
Publié par
Publié le
14 mai 2012
Nombre de lectures
108
Langue
English
Poids de l'ouvrage
5 Mo
iDiscovering Earth's Hidden Frontiersthrough Scientific Ocean DrillingInitial Science Plan 2013 - 2023Draft 2: 19/08/2010Vision:To deliver the Earth and Life Sciences discoveries needed to meet the challenges so-ciety faces as stewards of our changing planet.Mission:To employ ocean drilling technology required to obtain unique insight to under-stand and predict Earth’s dynamic system and its impactsTo inspire & train the next generation of geoscientistsTo communicate our scientific discoveries to the public and to decision makersiiThe Science Plan Writing CommitteeMike Bickle (University of Cambridge, Chair);Christina Ravelo (UCSC) ;Heiko Palike (NOC, University of Southampton);Rob DeConto (University of Massachusetts, Amherst);Fumio Inagaki (JAMSTEC);Katrina Edwards (University of Southern California);Naoh Ohkouchi (JAMSTEC);Andrew Fisher (University of College of Southern California);Damon Teagle (NOC, University of Southampton);Demian Saffer (Penn State);Gilbert Camoin (CNRS);Peter Barrett (University of Wellington);Shuichi Kodaira (JAMSTEC);Richard Arculus (Australian National University );Richard Norris (Scripps Institution of Oceanography)LiasonsHans Christian Larsen, (IODP-MI)Maureen Raymo, (SASEC)Hiroshi Kawamura, (IODP-MI)Yoshi Tatsumi, (BoG)Susan Humphris, (BoG)iiiContentsPreface 1Executive Summary 21 Introduction 41.1: Scientific Overview 41.2: Implementation 61.
Voir
i
DiscoveringEarth'sHiddenFrontiers throughScientificOceanDrilling
Vision:
InitialSciencePlan2013-2023
Draft2: 19/08/2010
To deliver the Earth and Life Sciences discoveries needed to meet the challenges so-cietyfacesasstewardsofour changingplanet.
Mission:
To employ ocean drilling technology required to obtain unique insight to under-standandpredictEarth’sdynamicsystemanditsimpacts
Toinspire&trainthenextgenerationofgeoscientists
Tocommunicateourscientificdiscoveriestothepublicandtodecisionmakers
TheSciencePlanWritingCommittee
ii
MikeBickle(UniversityofCambridge,Chair);
ChristinaRavelo(UCSC); HeikoPalike(NOC,UniversityofSouthampton); RobDeConto(UniversityofMassachusetts,Amherst);
FumioInagaki(JAMSTEC); KatrinaEdwards(UniversityofSouthernCalifornia); NaohOhkouchi(JAMSTEC); AndrewFisher(UniversityofCollegeofSouthernCalifornia); DamonTeagle(NOC,UniversityofSouthampton); DemianSaffer(PennState); GilbertCamoin(CNRS); PeterBarrett(UniversityofWellington); ShuichiKodaira(JAMSTEC); RichardArculus(AustralianNationalUniversity); RichardNorris(ScrippsInstitutionofOceanography)
Liasons
HansChristianLarsen,(IODP-MI) MaureenRaymo,(SASEC) HiroshiKawamura,(IODP-MI) YoshiTatsumi,(BoG)
SusanHumphris,(BoG)
Contents
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Preface1 ExecutiveSummary2 1 Introduction 4 1.1:ScientificOverview 4 1.2:Implementation 6 1.3:Management 6 2:ClimateandOceanChange:ReadingthePast,InformingtheFuture8 2.1:Introduction 8 2.2:Determiningclimatesensitivity 10 2.3:Oceanacidificationandthecarboncycle 14 2.4:Roleofpolaricesheetsinpastandfuturesea-levelchange 15 2.5:Regionalclimatevariabilityandthehydrologiccycle 17 2.6:RequirementsandLinkages 18 3:TheBiosphere:Co-evolutionofLifeandthePlanet20 Introduction 20 3.1)RecordsoftheOceanBiosphere21 3.1.1:Marineandterrestrialecosystemevolution 21 3.1.2:Extendingevolutionarytheory:Exploitationoftemporalrecords 24 3.1.3:Oceanbiogeochemistryandthecarboncycle 26 3.2)DeepLife 28 3.2.1:Introduction 28 3.2.2:Extentanddispersalofdeeplife:Biomes,connectivity,andecology30 3.2.3:Survival&evolutionunderstress 31 3.2.4:Biogeochemicalimpacts 31 3.2.5:Strategies,linkagesandrequirements35 4:DeepEarthProcesses36 4.1: Introduction 36 4.2:RenewingEarth’sSurface37 4.2.1:Deepdrillingofintactfast-spreadoceaniccrust 37 4.2.2:Observationsofactiveprocesses 40 4.2.3:Heterogenousslow-spreadcrust:Tectonicwindowstothelowercrust andmantle 40 4.3:TheReactiveEarth’scrust:Rocks,fluidsandlife40 4.4:RecyclingtheCrust:Arcsandcontinents 42 4.4.1:ArcMagmatism:Generationofthecontinentalcrust 44 4.4.2:Subductioninitiationandthe4-developmentofArcs 46 4.4.3:Hazardsandresources 47 4.5:RequirementsandLinkages 47 5:EarthinMotion:Geohazards,fluidflow,andactiveexperimentation48 5.1:Introduction 48 5.2:Geohazards:Earthquakes,landslides,andtsunamis 48 5.3:FluidsinMotion:Agentsofmechanical,thermal,chemical,andbiological change 51 5.4:Establishingacontinuedpresencewithinthesubseafloorrealm 54 5.5:Requirementsandlinkages 55
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{notincludedinthisdraftanaM:7,tnemegOicblPuh,acreut:6Implementation, Awareness,andEducation,Appendices}
Boxes
Box2:1 Box2.2: Box2.3: Box2.4:
Box3.1: Box3.2: Box3.3:
Box3.4: Box3.5: Box3.6: Box3.7:
Box3.8:
Box3.9:
Box4.1: Box4.2: Box4.3: Box4.4
Box5.1: Box5.2: Box5.3:
Pastclimate:ConstraintsfromOceanDrillingDat Model-dataIntegration TransformativeNewProxyDevelopments Arctic&Antarctic
9 10 11
13
HumanEvolutionandClimateChange 23 Biostratigraphy 24 DynamicsofSpeciation,EvolutionandExtinctionintheOceans 25 HistoricalPerspectiveonSubseafloorMicrobialLife28 Deep-biosphereInitiative29 LifeattheFringe 30 TranslationsfromDarwin–theEarthasaNaturalLaboratoryfor StudiesofMicrobialEvolution31 GenomicAnalysisofEnvironmentalSamples:Newlensesto EvolutionaryProcesses32 FrontiersinSubseafloorMicrobiology33
QuestfortheMantle:MoHole SerpentiniteSeas Sub-seafloorCaptureandStorageofCO2 MissiontoDeepArcCrust–“andesiteproblem”
BoreholeExperiments TheSpectrumofSeismicityandFaultSlipPhenomena A“Stethoscope”onEarthquakeFaults
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38 41 43 45
49
52
Preface
1
This document presents the second draft of the New Science Plan for the Integrated Ocean Drilling Program2*. The IODP2is an international program to explore beneath the oceans by drilling the ocean floor, recovering core and carrying out real-time observations and experi-mentsinboreholes. The Plan presents the scientific frontiers for which exploration beneath the oceans will en-able transformative advances. The topics include those of fundamental interest as well as urgent questions related to management of the environment, resources and geological hazards. Explo-ration beneath the oceans is essential for understanding processes in the solid Earth, oceans, at-mosphere, climate and the biosphere and their important inter-relationships. The science structure of IODP2managed in a responsive mode with the flexibility to respond to anwill be evolving science agenda, seize new opportunities and respond rapidly to emerging urgent is-sues. The Plan summarises the important scientific, educational, and societal benefits to be gainedbydeployingthistransformationalnewinfrastructure. This Science Plan was prepared by the Science Writing Plan Committee, nominated by the IODP community, short listed by the Science Advisory Structure Executive Committee and confirmed by the International Working Group+. Others who assisted with the preparation of parts of this document by contributing text, figures, or comments include Paul Pearson, Sasha Turchyn, Mike Cheadle and Ros Rickaby. This document draws heavily from many earlier workshops and meeting reports, but we wish to specifically acknowledge the INVEST Work-shop held September 22-25, 2009 in Bremen co-chaired by Wolfgang Bach and Christina Ravelo.
The document is currently incomplete. Figures will be properly planned and redrawn and at present are included as examples. The implementation, management, education and outreach sections have yet tobedrawnup.Thelayout,numberingandtitlesandsubtitlesareallpreliminary.
Weneedanameforthenewprogram! *
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ExecutiveSummary Geological processes continually modify the bined with targeted and transect drilling to re-Earth we live on and, in doing so, control the evolution cover high resolution (sub-millenial) records of landscape, oceans, atmosphere and biosphere. and improved correlation between records, is These processes are both of fundamental interest and revolutionising our ability to reconstruct past of immediate societal concern as anthropogenic activi- climatic states and their regional variability. ties impact the Earth’s surface environment, deplete Immediate applications will be to the determi-natural resources and become increasingly sensitive to nation of past climate sensitivity to atmospheric naturalhazards. CO2, ice sheet instability and sealevel change, the response of the hydrological cycle to chang-Drilling in the deep oceans is essential to our un- ing climate, and the impacts of anthropogenic derstanding of the processes that shape the Earth. This oceanacidification. is because only the deep oceans preserve the sedimen-tary sequences that record continuous temporal re- Advances in genetics, molecular biology, cords of Earth processes (the ‘fourth’ dimension), and geochemistry and palaeobiology coupled with because the oceans cover the active manifestations of recovery of high resolution time records by the Earth’s driving tectonics which reveal its inner drilling and the ability to characterise the physi-workingsandcausemajorgeologicalhazards. cal and chemical states of the ocean will allow determination of how past ocean ecosystems Past ocean drilling has been central to many of the responded to environmental change. Especially most important advances in the Earth sciences over the important is how these ecosystems responded last 40 years including verifying plate tectonics and es- to climatic warming analogous to predicted fu-tablishing the science of palaeoclimate. Most recently ture warming. The time and spatial resolution ocean drilling has revealed the magnitude of past cli- of the records will provide tests for modern the-matic changes in the polar regions, documented ories of evolution. The ocean biosphere may be changes the instability of icesheets, extended high res- an important moderator of the Earth’s surface olution climate records back to ~ 2 million years and environment and the drilling records will be drilled down to fossil magma chambers in the lower critical in resolving the leads and lags between part of intact oceanic crust. The current program in- changes in the biosphere and climate and hence cludes the ambitious multi-expedition NanTroSEIZE causalityinpatternsofchange. project to reveal the mechanisms of the most damaging subduction zone earthquakes, expeditions investigat-ing the little-known deeply buried microbial commu- Drilling has discovered a vast “deep bio-nities and drilling to understand mantle convective sphere” buried in sediments and the crust. The motionsandmelting. limits of life in these environments remains to be determined, as does their role in global geo-The new IODP2 cycles. New genetic sequencing tech- chemicalprogram will employ a spectrum of drilling technologies and downhole instrumentation niques will enable classification of the to enable transformative advances in understanding of microbial populations and investigation of their climate science, in the operation of biological commu- ecology. Study of these isolated communities nities in the oceans and in the subseafloor, and in the will provide new perspectives on evolutionary operation of the solid Earth and its interactions with processes and the origin of life as well as the thesurfaceenvironment. limits on life and the potential for life on other planets. Drilling is the only way to access the Explanation of the nature and causes of climate deepbiosphere. change on all timescales is of fundamental scientific significance with urgent societal implications. Only oceanic sediments contain the palaeoclimate records The continually recycled oceanic crust with the spatial distribution and time range against most directly reflects mantle processes. Drill-which we can test the climate models used to predict ing strategies and technologies have now ad-future climate change. These records have already re- vanced to the stage where the whole oceanic vealed failures of the modelling including prediction crust and uppermost mantle can be sampled. of meridional temperature gradients during warmer The consequent understanding of the interact-climates and the rapidity of icesheet collapse and ing magmatic and hydrothermal processes that sealevelrise. form the crust will constrain the composition and compositional heterogeneity of the mantle. The development of new and more sophisticated This information will be critical to resolving the proxies is enabling the determination of the physical, dilemma posed by recent exquisite seismic chemical and biological states of past oceans, tomographic images of the Earth showing palaeo-ocean circulation, the behaviour of ice sheets subduction zones penetrating the lower mantle and past continental vegetation patterns. This, com- whereas the isotopic compositions of mantle
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magmas require long-term segregation of their tant in monitoring hydrothermal circulation in the sourceregions. ocean crust and its sedimentary veneer and in arc Better estimates of hydrothermal fluxes settings, as well as assessing both the geohazard and possible resource in the dynamic gas hydrate tdherro-uogf-hmtahgenoitcuedaenicuncrcuesrttaiwniltliersesionlvgeecoucrhreenmticora-laccumulations.Continuouspassivemonitoring and active experiments with natural or artificial fluxes between the solid Earth, oceans and atmo- perturbations reveal hydrological architectures and sopfhtehree.cTurhreesnetarrievecruirnreenitnlpyuctatlocutlhaeteodcoenantshewbhaiscihsdeformationprocesses.Thedevelopmentofcabled may be may seriously perturbed by short-term cli- networks of such observatories will enable matic change. Past changes in seawater composi- real-time observations with the potential of early warning systems for geohazards associated with itimopnriwntilolntbheeorecceaonncstrruusct.tedfromitshydrothermalearthquakesandtsunamis. Deep drilling in island arcs will test the hy- The results from drilling will make critical contributions to interdisciplinary research pro-spuobthdeuscitsiotnhaztotnheecproonctiensesnets,alrecrvuesatlitshepraordcucheyddrboygramsonEarthprocessesincludingworkonmod-thermalcontributiontooceanicgeochemica-lellingfutureclimatechange,ecology,evolutionary budgets and associated resources, and study the processes and the interactions between the bio-majorseismicandvolcanichazardsposedbysEpahrtehredaynndatmhiecsE,aartnhd’stshuerfamcaenyenpvriroocnesmseesnt,insotlhide subductionzones. oceans that exert fundamental controls on climate, The developments in sub-seafloor observato- provideresourcesandgeneratemajorhazards. ries now permit observations on phenomena re-lated to mechanical, hydrogeological, thermal, The new drilling program will exploit the in-chemicalandmicrobiologicalprocessesinrealtvieosntmasenwtselilnadsrsiltlrastheigpiscadnedvdeloowpnmheonltesiinnstrmuomuentnitnag-time as well as time-series sampling of fluids. of drilling expeditions during the IODP. The Borehole observations on fluids in the sub non-riser drill ship, Joides Resolution, supplied -seafloor are particularly important as they trans- and operated by the US National Science Founda-port heat, chemicals, nutrients and microbes, lubri- tion, was refurbished in 2008. The riser drill ship, cate faults and their hydraulic transients are sensitivetodeformationevents. Chikyu, supplied and operated by JAMSTEC com-menced IODP operations in 2007 and is capable of Theinstallationofnetworkeddown-holeob-dridllinvgervperreyssduereedpfhoorlmesatiaonnds.inThheolEeusrionpeuannstCaoblne-servatories to form a long-term real-time monitor- an o ingsystemintheNanTroSEIZEexperimentwillcsioarltiisutmrifgorsOwcheiacnhRaelsleoawrcshdDrirlillliinnggsinuplpoliceastisopnes-r e t u r n u n p r e c e d e n t e d d e t a i l c o n c e r n i n g seismogenic processes, particularly the newly dis- inaccessible to the Joides Resolution or Chikyu, covered episodic tremor, low frequency and slow suchasshallowwaterorice-coveredseas. slip events. Borehole observatories will be impor-
ChikyuandMt.Fuji
