Discovering the Deep: a Photographic Atlas of the Seafloor and Ocean Crust

432 Pages·2015·57.622 MB·English

by  Fornari, Daniel J.;Karson, Jeffrey A.;Kelley, Deborah S.;Perfit, Michael R.;Shank, Timothy M

Discovering the Deep
A Photographic Atlas of the Seafloor and Ocean Crust
ThedeepoceansandglobalseaflooraretrulyEarth’slastfrontier. cabledobservatory,fundedbytheNSF.SheistheformerChair
Theyremainlargelyunexplored,yetarecriticaltooursurvival of the UNOLS Deep Submergence Science Committee. Her
onthisplanet.Thismagnificentvolumetransportsyoutovolca- research examines the linkages between submarine volcanoes,
noes, boiling hot springs, and fault zones in mountains a mile underwater hot springs and how they support life in the
beneaththeoceansurface,wherebizarrelandscapeshostexotic absenceofsunlight.Dr.Kelleyhasparticipatedinover35blue
lifeformsthatrivalthemostimaginativesciencefiction. watercruisesroutinelyusingroboticvehicles,andhasbeenon
over50Alvindeep-seasubmersibledives,todepthsasgreatas
Illustratedthroughoutwithspectacularcolorphotographs,the
4000meters.
book starts with a historical summary of seafloor exploration
and the developing technologies used to study this extreme Daniel J. Fornari is a marine geologist and Senior Scientist at
environment.Itthenpresentsaseriesofchaptersthatdescribe the Woods Hole Oceanographic Institution (WHOI). He was
thedistinctivegeologicalcomponentsoftheEarth’soceanfloor thefirstChiefScientistofDeepSubmergenceatWHOI,apast
and the myriad environments found along mid-ocean ridges Director of WHOI’sDeep Ocean Exploration Institute (DOEI),
wherenewcrustiscreated.Itisherethatdiscoveriesofchemo- and was a Chair of the Ridge 2000 Program, a NSF-funded
synthetic biological communities revolutionized our ideas national program studying mid-ocean ridges. Dr. Fornari is
about the origins of life and the potential for life’s existence the author or co-author of over 100 research publications and
elsewhereintheUniverse.Theauthorsprovideelegantexplan- hasparticipatedinover100researchcruisesandasmanydives
ationsofhowthevariousgeologicalandhydrothermalfeatures indeep-seasubmersibles.Hisresearchfocusesonvolcanicand
of the seafloor are formed through physical, chemical, and hydrothermal processes along the global mid-ocean ridge,
biological processes, and present comparative examples from usingavarietyofsurfaceanddeep-towedsonarsystems,sub-
placeswheretheseafloorisexposedonland. mersibles,ROVs,andAUVs.
DiscoveringtheDeepisanindispensablereferenceforresearch- Michael R. Perfit is Professor of Geological Sciences at the
ers, teachers, and students of marine science, and a visually University of Florida, where he has received several awards
stunningresourcethatwillenlightenandintrigueoceanograph- forexcellenceinteaching.Hehasco-authoredmorethan100sci-
ersandenthusiastsalike.Asuiteofonlineresources,including entificpublicationsonvolcanismandmagmagenesisatoceanic
photographsandvideoclips,combinewiththebooktoprovide spreadingcentersandseamounts.Dr.Perfithasparticipatedin
fascinating insights into the hidden world of seafloor geology 30oceanographicresearchcruisesandtakenmorethan35dives
and biology using the latest deep-sea imaging and geological inAlvin.HehasservedastheChairoftheDeepSubmergence
concepts. ScienceCommittee,andisalsoaFellowoftheGeologicalSoci-
ety of America and the American Geophysical Union, and a
JeffreyA.KarsonisProfessorofGeologyintheDepartmentof
TrusteeoftheConsortiumforOceanLeadership.
EarthSciencesatSyracuseUniversityandaFellowoftheGeo-
logical Society of America. He investigates the interplay of Timothy M. Shank is an Associate Scientist in the Biology
magmatic construction and mechanical deformation of exten- DepartmentoftheWoodsHoleOceanographicInstitutionand
sional and transform fault environments from ophiolites, con- Director of WHOI’s Ocean Exploration Institute. His research
temporary oceanic crust, Iceland, continental rifts, and focusses on ecological and evolutionary processes that affect
continental margins. Professor Karson has participated in ecosystem structure, faunal evolution, and biodiversity in the
numerous field projects and seafloor research cruises world- deep sea. Dr. Shank has conducted more than 57 scientific
wide. He is the author or co-author of over 150 publications expeditions, using a wide variety of submersibles, ROV and
onseafloorspreadingandrelatedphenomena. AUVsystems(includingmorethan50Alvindives).Heiscur-
rently the Director of the Hadal Ecosystems Studies Program,
DeborahS.KelleyisaProfessorintheSchoolofOceanography
pioneeringthefirstresearchuseofthefull-oceandepthhybrid
attheUniversityofWashingtonandalsoAssociateDirectorof
ROV(Nereus)inthedeepesttrenches.
ScienceforthefirstUSunderwaterhigh-power,high-bandwidth
Praise for
Discovering the Deep
“Though it’s fashionable to say we know little about the theEarthandthetechnologyrequiredtoinvestigateit.Not
mysteries of the deep, this book shows the vast wealth of sinceBruceHeezenandCharlieHollister’sclassicbook,The
understanding that pioneering researchers have already FaceoftheDeep,firstpublishedin1971,haveweseensucha
gleaned,withtheirprobingsoundwaves,persistentrobots comprehensivephotographicatlasofwhatliesinthehidden
and courageous submariners. This is the book I wish I’d depthsofthesea.”
had on my eight deep ocean expeditions, to better under- Dr.RobertD.Ballard,PresidentoftheOcean
stand the wonders I was gazing upon. A must-own for ExplorationTrust
anyone in the ocean sciences, and for those simply curious
“Discovering the Deep is an exquisite synthesis of the com-
about what lies down there in the most remote realm on
plexityofnaturalprocesses,thebeautyofoftunseenenvir-
ourplanet.”
onments,andthecriticalscientificdiscoveriesofourrecent
JamesCameron,explorerandfilm-maker
past. To read this volume is to become an enlightened
“DiscoveringtheDeepwillopenyoureyestothelargestand travelerintothefascinatingrealmoftheseafloorandocean
most unexplored region on Earth – the global Mid-Ocean crust. No student of the natural world should be without
Ridge.MyownintroductiontotheMid-OceanRidgebegan thismagnificentatlasofourplanet’srichlystructureddeep
withtheFAMOUSExpeditiontotheMid-AtlanticRidgein oceanenvironment.”
1974, and this beautifully illustrated and comprehensive Dr.KathrynD.Sullivan,UnderSecretaryofCommerce
accountshowshowfarwehavecomeoverthelast40years forOceansandAtmosphereandNOAAAdministrator;
inourunderstandingofthisfundamentaltectonicfeatureof formerNASAastronaut
Discovering the Deep
A Photographic Atlas of the Seafloor and Ocean Crust
jeffrey a. karson
Syracuse University
deborah s. kelley
University of Washington
daniel j. fornari
Woods Hole Oceanographic Institution
michael r. perfit
University of Florida
timothy m. shank
Woods Hole Oceanographic Institution
UniversityPrintingHouse,CambridgeCB28BS,UnitedKingdom
CambridgeUniversityPressispartoftheUniversityofCambridge.
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©CambridgeUniversityPress2015
Thispublicationisincopyright.Subjecttostatutoryexception
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Firstpublished2015
PrintedintheSpainbyGrafosSA,Artesobrepapel
AcatalogrecordforthispublicationisavailablefromtheBritishLibrary
LibraryofCongressCataloginginPublicationdata
Karson,JeffreyA.
Discoveringthedeepaphotographicatlasoftheseafloorandoceancrust/JeffreyA.Karson,
SyracuseUniversity,NewYork,DeborahS.Kelley,UniversityofWashington,DanielJ.
Fornari,WoodsHoleOceanographicInstitution,Massachusetts,MichaelR.Perfit,University
ofFlorida,TimothyM.Shank,WoodsHoleOceanographicInstitution,Massachusetts.
pages cm
1. Oceanbottom–Pictorialworks. 2. Earth(Planet)–Crust–Pictorialworks. I. Title.
GC87.K372015
551.460800222–dc23 2014028680
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Contents
ForewordbyPaulJ.Fox pageviii 2.4 Unveilingtheoceaniclithosphere 38
Preface:NewviewsofEarthfrombelowtheoceans ix 2.5 Geophysicalframeworkofseafloor
Acknowledgments xv spreading 39
2.6 Compositionoftheoceaniccrust 41
1 Entering the abyss: oceanographic
technology 1 2.7 Directaccesstotheoceaniccrust 43
2.8 Unravelinggeologyontheseafloor 45
1.1 Firstencounters 1
2.9 Deepcrustaldrilling 46
1.2 Acousticimaging 4
1.2.1 Echosounding 4 2.10 Oceaniccrustandmantleonland 49
1.2.2 Satelliteoceanography 5 2.11 Linkingophiolitestooceaniclithosphere 50
1.2.3 Multibeamsonar 6
2.12 Cross-pollinationofdataandconcepts 51
1.2.4 Sidescansonar 7
1.3 Twentieth-centurydevelopmentsin 3 Diversity in seafloor spreading 56
deep-seaopticalimagingtechnology 10
3.1 Seafloorspreading:afirst-orderglobal
1.4 Submergencevehicles 16 process 56
1.4.1 Human-occupiedvehicles 16
3.2 Magmabudget:keytovariabilityalong
1.4.2 Tetheredroboticvehicles 18
theMORsystem 58
1.4.3 Autonomousunderwatervehicles 18
3.3 Diversemorphologiesofspreadingcenters 59
1.4.4 Hybridremotelyoperatedvehicles 22
3.3.1 Fast-spreadingMORs 59
1.5 Seismicmonitoringandimaging 22
3.3.2 Slow-spreadingMORs 60
1.5.1 Revealingthedetailsofcrustaland
3.3.3 Intermediate-spreadingMORs 60
uppermantlestructureatMORsusing
3.3.4 MORsegmentation 60
multichannelseismictechniques 22
3.4 Componentsofspreadingsystems 63
1.5.2 Ocean-bottomseismometers 24
3.4.1 Neovolcaniczone 63
1.5.3 Recordingseismicityalongtheglobal
3.4.2 MORfaults 67
MORaxisusingautonomous
3.4.3 Oceaniccorecomplexes 69
hydrophonesandtheSOFAR
3.4.4 Transformfaults 71
channel 25
3.4.5 Propagatingrifts 73
1.6 Oceandrilling:probingintotheseafloor 28
3.4.6 Microplates 75
1.7. Real-timeaccesstotheoceanrealm:
3.5 Internalstructureoftheoceaniccrust 75
oceanobservatories 29
3.5.1 Uppercrust 76
1.8 Telepresence:seagoingparticipationand 3.5.2 LowercrustandMohotransitionzone 77
researchthroughtheInternet 32 3.5.3 Uppermantle 83
3.6 Seafloorspreading:fastandslow 84
2 Earth beneath the sea 35
2.1 AnewunderstandingofEarthandocean 4 Hydrothermal vents 87
history 35
4.1 Oasesofthedeep 87
2.2 Seafloorspreading:aconsequenceofplate 4.1.1 Fluidoverturnintheoceaniccrust 90
tectonics 36 4.1.2 Themetamorphosisofseawaterto
2.3 Continentaldrift,“geopoetry,”andseafloor hydrothermalfluidsinunderwater
spreading 37 volcanoes 93
●
vi CONTENTS
4.1.3 Formationofblacksmokerchimneys 95 4.10.3 Sulfidechimneys 167
S
T 4.1.4 Boilingfluidsinandattheseafloor 97 4.10.4 Extinctdeposits 168
N
TE 4.1.5 Gasesfromthedeep 99 4.10.5 Dikingevents,seismicity,and
N
O 4.1.6 Impactofvolcaniceruptions 99 hydrothermalflow 170
C 4.1.7 Oceaniccrust,tectonics,andvent 4.10.6 The1999–2000dikingevent 171
diversity 103 4.10.7 The2005dikingevent 172
4.1.8 Lifeintheextreme:microbesof 4.10.8 Firstreal-timemonitoringof
thedeep 105 geophysical,chemical,andbiological
4.1.9 Chemosynthesisandthemetabolic processes 174
menu 107 4.11 AxialSeamount:robustvolcanismonthe
4.1.10 Lifeintheextreme:ventfauna 108 JuandeFucaRidge 177
4.2 Arcticridges:fireandice 111 4.11.1 AxialSeamounteruptions 180
4.2.1 GrimseyField,northofIceland 112 4.11.2 Shallowhydrothermalventsites 182
4.2.2 Trollveggen(TrollWall)Field,Mohns 4.11.3 Boilingfluids 183
Ridge 112 4.11.4 Eruptionsandbiologicalcolonization 185
4.2.3 SoriaMoriaField,MohnsRidge 112 4.11.5 Wiringanactivesubmarinevolcano 186
4.2.4 Lokeslottet(Loki’sCastle)Field 113 4.12 GuaymasBasin:ventingatsedimented
4.2.5 Arcticventfauna 113 ridges 187
4.3 MenezGwen:ashallowventsystemon 4.12.1 GuaymasTroughandventing 189
theMAR 117 4.12.2 Microbiallifeinsedimentedsystems 190
4.4 Luckystrike:hot-spotinfluencedvent 4.12.3 Faunainhydrocarbon-rich
systems 121 environments 191
4.4.1 Hydrothermalventing 122 4.13 EastPacificRise:thefastestspreading
4.4.2 Animalcommunities 125 centeronEarth 193
4.5 Rainbow:hybridgabbroic-and 4.13.1 Evolutionoffast-spreading
ultramafic-hostedvents 127 hydrothermalsystems 197
4.13.2 RelationshipsbetweenEPR
4.5.1 Carbondioxide-,hydrogen-,
hydrothermalventsandbiological
andmethane-enrichedfluids 127
communities 199
4.5.2 Animalcommunities 129
4.14 GalápagosSpreadingCenter:firstvent
4.6 Lostcity:anewkindofventfield 131
4.6.1 LostCitygeology 131 discoveryonaspreadingcenter 204
4.14.1 Ventactivity 204
4.6.2 Anancientfield 133
4.14.2 Discoveryofhigh-temperaturevents 205
4.6.3 Alkalinefluidsrichinhydrocarbons 134
4.14.3 RosebudandCalyfieldVentFields 207
4.6.4 Lifeinhigh-pHsystems 141
4.14.4 UkaPachaandPegasusVentFields 209
4.6.5 ArarebiosphereatLostCity 142
4.6.6 Macrofaunalcommunities 142 4.14.5 TempusFugitVentField 210
4.15 CentralIndianRidge:anewbiogeographic
4.7 TAG:thelargestfieldknown 145
province 211
4.7.1 TheTAGmound 146
4.15.1 KaireiVentField 211
4.7.2 Long-livedventing 146
4.15.2 EdmondVentFeld 213
4.7.3 Aggregatingshrimp 149
4.15.3 KaireiversusEdmondfauna 215
4.8 Logatchev:ultramafic-influencedventsites 150
4.8.1 Hydrothermalventing 153
5 Submarine volcanism: fire beneath
4.8.2 LifeinhighCO ,CH ,andH systems 154
2 4 2 the sea 217
4.9 SouthAtlantic:extremeventtemperatures 156
5.1 Volcanoesonlandandunderthesea 217
4.9.1 SMARventfauna 159
5.2 Submarinelavas 218
4.10 Endeavour:oneofthemost
remarkableplaces 162 5.3 Historicalperspectives 220
4.10.1 Endeavourgeology 164 5.4 Directobservationsofthelavaunits
4.10.2 Ventfields 165 fromtectonicwindowsandcrustaldrilling 220
●
CONTENTS vii
5.5 Seafloorvolcanoesalongthemid-oceanridge 225 7.3 Deformationandmetamorphisminthe
C
5.6 Submarinelavamorphologies 228 middletoloweroceaniccrust 295 O
N
7.3.1 Oceaniccrustalmetamorphism 297 T
5.7 Eruptionsontheseafloor 235 E
7.3.2 Hydrothermalmetamorphism 298 N
T
5.8 Mid-oceanridgelavageochemistry S
7.3.3 Deformationandmetamorphismin
andmagmaticprocesses 238
oceaniccorecomplexes 299
5.9 CompositionalvariabilityofMORB 241
7.4 Petrology,geochemistry,andmagmatic
5.10 CrystalsinMORB 245 processesinoceanicgabbros 300
5.11 GeneratingMORBmagma 247 7.4.1 Petrology 301
7.4.2 Gabbrogeochemistry:decipheringthe
5.12 Historicsubmarineeruptions 247
chemicalfingerprintsofmagmatic
6 Dike intrusion and sheeted dike processes 301
complexes 255 7.5 Gabbroicrocksinophiolites 304
7.5.1 Sheeteddike–gabbrocontactin
6.1 Seafloorspreading:onemeteratatime 255
ophiolites 305
6.2 Dikesbeneaththeseafloor 258
7.5.2 Internalstructureofgabbroicand
6.2.1 Dikesandsheeteddikesincrust
relatedrocksinophiolites 306
formedatfasttointermediaterates 260
7.5.3 GeologicalexpressionsoftheMoho 310
6.2.2 Dikesandsheeteddikesin
7.6 Buildingthemiddletoloweroceaniccrust 313
slow-spreadingcrust 266
6.2.3 DikesandsillsatsedimentedMORs 267
8 Peridotites: windows into mantle
6.3 Petrologyandgeochemistryofsheeteddike processes 317
complexes 267
8.1 BelowtheMoho:theoceanicmantle 317
6.4 Metamorphisminsheeteddikes 271
8.2 Mantlerocks 318
6.5 Dikesandsheeteddikecomplexesonland 272
8.3 Peridotiteexposuresontheseafloor 319
6.5.1 Generalformandinternalstructure
8.3.1 Peridotitesfromsuperfast-to
ofdikes 273
intermediate-ratespreadingcenters 323
6.5.2 Internalstructureofdikeswarms
8.3.2 Peridotitesfromslow-to
andsheeteddikecomplexes 275
ultraslow-spreadingMORs 324
6.5.3 Contacts:linkingthelavaandgabbroic
units 278 8.4 Serpentinizationontheseafloor 328
6.6 Dikeintrusionalongspreadingcenters 282 8.5 Peridotitesinophiolites 331
6.6.1 Dikeintrusioneventsinspreading 8.6 Peridotitepetrologyandgeochemistry 332
environments 282 8.6.1 Peridotitemineralogyandphasechemistry 335
6.7 Accretionoftheupperoceaniccrustfrom 8.6.2 Peridotitegeochemistry 336
sheeteddikes 283 8.7 Evolutionoftheoceanicmantlelithosphere 338
8.8 Meltgenerationandtransport 338
7 Gabbroic rocks: clues to magmatic
processes 286 9 Future research 342
7.1 Thefoundationoftheoceaniccrust 286
Abbreviations 346
7.2 Plutonicrockexposuresontheseafloor 289 Figurecredits 347
7.2.1 GabbrosfromfasttointermediaterateMORs 290 References 355
7.2.2 Gabbrosfromslow-spreadingMORs 294 Index 401
Foreword
AnalienapproachingEarthforthefirsttimewouldobserve Earthlive.SpanningenvironmentsfromtheArctic,Atlantic,
a watery planet but would have no clue as to what lies Pacific,andIndianOceans,theauthorsprovidecaptivating
beneath the blue-gray liquid surface. This book unveils images of these seafloor oases, which host novel microbes
andilluminates,inwaysneverbeforepossible,thathidden that use toxic gases rising from Earth’s interior as their
world and the astounding processes that occur at the energysource.
seafloorandwithintheoceaniccrust.Drawingfromunpar- Theauthorshavesucceededinpresentingaholisticview
alleledimageryanddatafromtwenty-firstcenturytechnol- of the oceanic crust from top to bottom. They present the
ogy, which includes human-occupied and robotic vehicles, current state of knowledge on the complex and beautiful
sophisticatedsensorsandanalyticaltechniques,theauthors formsofvolcanicflowsthatpavethemid-oceanridgecrest
havesucceededin“pullingtheplug”ontheglobaloceanso tothemassivebasallayersofintrusive,plutonic,andultra-
that the awe-inspiring terrane of the ocean floor and pro- maficrocksthatuntilrecentlyhavebeendifficulttosample
cessesthatformitarerevealed. andplaceintheirpropergeologicalcontext.Thevariations
Itwas44yearsagothatBruceHeezenandCharlesHoll- instyleandstructuralcomplexityoftheseprimaryunitsare
ister publishedtheir seminalbook,TheFaceofTheDeep,an nowknowntobecriticaltotheconstructionofallmid-ocean
engaging and informative text that used analog seafloor ridges, from ultra-slow to fast, and the hydrothermal
photographstohighlightandinterpretthemyriadprocesses systemsandlifethattheysupport.Thisworkendswithan
operatingintheglobalabyss.DiscoveringtheDeepsetsanew important look towards the future and new technologies
benchmark for a comprehensive treatise about visualizing that will be required to address upcoming opportunities
the seafloor, how ocean crust forms, and the amazing life andchallengesinunderstandingthevastoceansthatmake
forms that thrive in one of the most extreme environments Earthhabitable.
on Earth – submarine hot springs. It presents up to date, The five authors of this atlas are all recognized as indi-
integrated multidisciplinary concepts about the mid-ocean viduals who have made significant contributions to our
ridge and its role in plate tectonics and developing the understanding of the mid-ocean ridge system. They have
architectureoftheoceaniccrust.Theauthorsalsosynthesize succeeded in synthesizing the many different, but comple-
published data from mid-ocean ridge analogs on land – mentary data sets – weaving together a text that elegantly
ophiolites – to better understand how oceanic crust is gen- takes the reader on a journey from hydrothermal vents
erated and the far-reaching implications of these processes down through the oceanic crust. They tell a story that is
forinterpretingEarthandoceanhistory. entertaining, illuminating, and scholarly. For a layperson
AsastudentofHeezen,acontemporaryofHollister,and interested in learning more about fundamental planetary
someonewhohasspentmostofhiscareerstudyingthemid- process, a student of marine geology just embarking on a
ocean ridge using ships and the submersible Alvin, I was career, or a seasoned investigator of oceanic crustal pro-
drawn into all aspects of this compelling and masterful cesses,thisatlasoftheseafloorandoceaniccrustissureto
synthesis, especially the high-resolution images of mid- expand horizons and enrich understanding of how our
ocean ridge volcanic and hydrothermal terranes and biota. planetworksforallreaders.
The more than 500 stunning images of the seafloor, many
neverbeforepublished,weretakenusingthelatestindeep- paulj.fox
seadigitalcameraandlightingtechnology.Theremarkable ProfessorEmeritus
images provide glimpses of underwater eruptions where DepartmentofGeology&Geophysics
molten rock turns to glass almost instantly, and black- TexasA&MUniversity
smoker vents where the most exotic life forms known on McLeod,Montana