Scientific Ocean Drilling: Accomplishments and Challenges
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Transcript of Scientific Ocean Drilling: Accomplishments and Challenges
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WHAT IS SCIENTIFIC OCEAN DRILLING?.........................................................................................2
CYCLES OF THE SOLID EARTH.........................................................................................................4
Earths Magnetic Field .........................................................................................................................4
Continental Breakup and Sedimentary Basin Formation ......................................................................5
Structure, Composition, and Formation of the Ocean Crust ................................................................5
Subduction Zone Processes and Seismogenic Zones ........................................................................6
Large Igneous Provinces ....................................................................................................................7
FLUID, FLOW, AND LIFE ON THE SUBSEAFLOOR.............................................................................8
Heat Flow, Fluid Flow, and Geochemistry............................................................................................8
Hydrothermal Vent Processes .............................................................................................................9
The Subseafloor Biosphere ...............................................................................................................10
Gas Hydrates ...................................................................................................................................11
EARTHS CLIMATE HISTORY ..........................................................................................................12
Past Warm Climate Extremes and the Greenhouse World .................................................................12
Cenozoic Ice Sheet Evolution and Global Sea Level Change.............................................................13
Orbital Forcing ..................................................................................................................................17
Abrupt Climate Change ....................................................................................................................18
Co-Evolution of Life and the Planet ...................................................................................................18
ASSESSMENT OF THE 2013-2023 SCIENCE PLAN .......................................................................21
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The U.S.-operated JOIDES
Resolution is a multipurpose
drillship that serves the
international scientic ocean
drilling community. Credit:
William Craword, IntegratedOcean Drilling Program U.S.
Implementing Organization
(IODP-USIO).
A rich
history oEarths past lies
beneath the ocean.The sediments and rock o the ocean foor contain records o active
biological, chemical, and geological processes that have shaped the
Earth over millions o years.
Scentc ocen rn hs spurre remrkbe proress n unerstnn mny ob
processes: conrmn the theory o pte tectoncs, ocumentn the hstory o Erths c-
mte system, nvesttn the roe o fu fow wthn the ocen crust, n scovern n
extensve subsefoor bosphere tht my we nhbt o the wors ocenc sements
n much o the pnets crystne crust.
Ths booket summrzes the nns o the Nton Reserch Counc report, Scientifc
Ocean Drilling: Accomplishments and Challenges. The report ooks t sncnt ccom-
pshments enbe by scentc ocen rn n so ssesses the potent or trnsor-
mtve scoveres bse on the reserch escrbe n Illuminating Earths Past, Present
and Future: The International Ocean Discovery Program Science Plan or 2013-2023,
scence pn or the next ece o scentc ocen rn.
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2
What is Scientic Ocean Drilling?
The ocen foor hos vst recor
o Erths hstory. The bs-
tc rock tht mkes up most
o the sefoor hos eo-
chemc cues bout pro-
cesses wthn Erths nteror.
Sements eposte bove
the rock prove normton
bout contons tht exste when
they were own. Unke sements
on n, whch cn be tere or even com-
petey remove throuh the ctons o
wn, wter, n tectoncs, sefoor sementshve rey been preserve n contnuous,
unsturbe yers.
Scentsts ccess ths recor o Erth
processes throuh scentc ocen r-
n, whch ows them to recover cores
on cynrc smpesrom the
sefoor. The rock n sements re
nyze n reserch borto-
res n rchve n repos-
tores or uture stuy.
Ocen rn so en-
bes reserchers
Scientists prepare a CORK or deployment.
Credit: William Craword, IODP-USIO.
to coect subseoor us n mcrobes,
s we s eophysc n eochemc
t, rom the borehoes et behn when
core s extrcte.
Put a CORK in it!
Every scentc ocen rn hoe proves
scentsts wth opportuntes or scovery.
Trtony, ths hs been throuh nyss o
the core extrcte rom the ocen foor. Some
hoes prove ton opportuntes to mon-
tor contons such s temperture, pressure,
n fu fow n the subsefoor throuh pce-
ment o sensors n the borehoe. The process o
coectn t rom borehoes s compcte
by the ct tht rn cn sturb ntur con-
tons n resut n exchnes between se-
wter n fus wthn the rock or sement.
To ow prmeters such s temperture
Global distribution o drill holes and sampling sites rom scientic ocean drilling
programs between 1968 and 2011. Credit: IODP-USIO.
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The following steps explain how an ocean drilling core iscollected aboard the drillship and prepared for use by
researchers.
1. The drill string is assembled and lowered throughthe moon pool, an opening in the ships hull to the water
below.Aspecicdrillbitischosenbasedontheproperties of the sediment or rock that is being drilled.
2. Once the core is extracted and brought back up to the rig oor,technicians carrythecoretothecatwalk,labelit,and
cut it into 1.5 meter (about 5 feet) sections.
3. Scientists analyze physical properties of the core, such asdensity, porosity, and magnetism.
4. The core is split lengthwise into two halves: the workinghalf, which scientists sample for use on board the drillshipand back in their laboratories; and the archive half, whichis kept unsampled for future comparison. Scientists
document the core in detailincluding its composition,grain size, and colorand take photos of the core forresearch purposes.
5. Scientists identify sections they want to sample on ship orstore for post-cruise research in their own laboratories.
6. Both halves are stored in refrigerated space in the shipshold. At the end of the cruise, the cores are stored in an
onshore repository under controlled conditions forfuture use.
Core on DeCk!
CORKs (Circulation Obviation Retrot Kits) are devices that
seal boreholes o rom seawater, more closely mimicking
the natural subseafoor environment. CORKs can be used
or pressure, seismic, strain, and temperature monitoring;
fuid sampling; and microbiological and perturbation experi-
ments. Credit: Modied rom Fisher et al., 2011.
n pressure to return to norm,
scentsts hve eveope CORKs
(Crcuton Obvton Retrot Kts)
evces tht se borehoes o rom
sewter, more cosey mmckn
the ntur subsefoor envronment.
Recenty, scentsts hve eveope
vnce CORKs tht cn se mu-
tpe seprte zones wthn sne
borehoe, corresponn to strtcton
oun wthn the sefoor.
Top right: Scientists careully split a rozen core section.
Credit: William Craword, IODP-USIO.
Bottom right: A technician helps carry a core rom the drill foor
to the catwalk. Credit: William Craword, IODP-USIO. 3
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4
SCiENTiiC OCEaN dRilliNg hs ven
reserchers better ccess to the Erths nte-
ror to better unerstn so Erth cyces
the processes tht enerte n moyErths crust. Over the st our eces, new
scoveres hve prove mportnt nshts
nto pte tectoncs, the process o contnent
rtn, the Erths mnetc e, the rchtec-
ture o ocen crust, n the processes tht
enerte mjor erthqukes n tsunms.
Earths Magnetic Field
deep wthn the qu outer core, the mo-
ton o moten ron oys enertes Erths
mnetc e. Over on tme sces, Erthsmnetc e swtches recton, cus-
n the mnetc poe to mrte
rom north to south n bck
n. Evence o these re-
verss s recore n ron-
bern mners tht
re bunnt n the
rocks tht mke
up the ocenc
crust. Ocen
rn hs owe reserchers to use the
mnetc propertes o these rocks to trce the
hstory o sefoor ormton over eooc tme.
The Theory o Seafoor Spreading
One o the rst mjor chevements o sc-
entc ocen rn ws the conrmton o
sefoor spren. Ocen rn owe
reserchers to coect sement smpes n
trnsect cross the M-atntc Re nthe South atntc Ocen. By ookn t m-
croscopc ornsms wthn sement recty
bove the ocenc crust, reserchers scov-
ere tht the e o the sements ncrese
wth stnce rom the re crest. Sement
e so correte we wth the pre, -
terntn mnetc sntures (corresponn
to reverss n Erths mnetc e) tht were
recore n the rocks s they spre wy
rom the m-ocen re. Ths ccompsh-
ment prove to be the ynchpn or estbshn
the prm o pte tectoncs,whch toy
serves s the ounton or unerstnnErths processes.
Generating a GeologicalTime Scale
Scentc ocen rn t ws essent
or corretn chnes n mnetc ntensty
Thin section o a basalt with olivine crystals, viewed under cross-polarized light.
Credit: IODP-USIO.
CyCles of the solid earth
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n orentton wth te mrne mcroos-s recors o versty, bunnce, n eo-
chemstry. When combne wth stronomc
cbrton, these sprte es o stuy con-
trbute to the eveopment o precse eo-
oc tme sce extenn 150 mon yers
nto the pst. Contnue renements usn
oby strbute smpes n ncresny
precse tn toos hve me the tme sce
n nspensbe too or etermnn the rtes
o mny o Erths processes, both on n
n n mrne systems.
Continental Breakup and
Sedimentary Basin
Formation
The process by whch contnents brek prt
n ntte sefoor spren hs been key
queston or sever eces. Throuhout
Erths hstory, contnent brekup hs usu-
y been ccompne by the eveopment o
new ocen crust foor between the rte con-
tnents, yet the compex trnston between
contnent n ocenc crust s st poory
unerstoo. in ton, sementry bsns
Petrologists work in the core lab. Credit: William Craword, IODP-USIO.
on the mrns cn ho hyrocrbon re-
sources o economc mportnce.
as ery s the m-1970s, ocen rn es
were exmnn the eometry o nt rment-
ton o crust t erent types o contnent mr-
ns. Scentsts me the scovery tht yers
o vocnc rock on the mm-rch Northest
atntc mrns were erupte on n, rther
thn unerwter s h prevousy been hypoth-
esze. at mm-poor mrns on the cost
o Spn n Newounn, upper mnte rocks
seprte contnent crust rom ocenc crust.
in combnton wth other pproches, scentc
ocen rn contrbute to unerstnn the
processes o contnent brekup, semen-
try bsn n hyrocrbon ormton, n
creton o new sefoor.
Structure,
Composition, andFormation o the
Ocean Crust
drn s the ony rect meth-
o to nvestte the orm-
ton, structure, n compo-
ston o the ocenc crust
n r upper mnte (to-
ether ce the ocenc
thosphere). Ery motvton
or rn the ocen crust
ocuse on unerstn-
n ts yere structure.
A core ready or analysis.
Credit: IODP-USIO.
5
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6
Subduction Zone
Processes andSeismogenic Zones
gret ntur hzrs such s vocnoes,
erthqukes, n tsunms cn be ener-
te t subucton zones, where two tectonc
ptes coe n one escens beneth the
other. Scentc rn expetons hve -
owe reserchers to probe the propertes o
subucton zones, eepenn the scentc
unerstnn o contons tht trer these
eooc hzrs.
Subduction Zone ProcessesThrouh scentc ocen rn, scentsts re
be to coect smpes ner subucton zone
bounres to hep etermne the nture o the
crust, sements, n fus n these reons.
These mters hve stnctve compostons
n cn ct s trcers or processes ento vocnc eruptons. Over tme, stues hve
evove rom smpy entyn these trcers to
constructn comprehensve moes tht hep
to unerstn the bnce o mters fown
nto n out o subucton reons.
Seismogenic Zone Experiment
Recenty, new scentc ocen rn n-
ttve, the Sesmoenc Zone Experment
(SEiZE), hs been ntte. its objectve s to
r throuh subucton zone bounry n
orer to expore the mechncs o re m-
ntue erthqukes (8.0 or reter) usn the
Whe nt eorts were hmpere by the
technc cutes o rn nto rock, whch
pose chenes or methos eveope to
r soter sements, enneern nnovtons
hve mprove hr rock rn cpbtes.
Ocen rn cores hve been use to conrm
the e o the oest ocenc crust, whch ws
orme bout 180 mon yers o. Becuse
t s much youner thn the e o the Erth,
ths scovery urther supporte the concept
tht ocenc crust crete t m-ocen res
s eventuy recyce t subucton zones.
Premnry observtons o r cores suest-
e tht the structure n composton o oce-
nc thosphere re erent, epenn on the
spren rte o the m-ocen re where
t s orme. urthermore, rn t
tectonc wnows (reons where
rocks tht re usuy eep n
the Erth hve been brouht
to the sefoor throuh
tectonc processes) hs
owe scentsts to
stuy both ower
crust n upper
mnte rocks.
A petrologist studies cores o oceanic crust.
Credit: John Beck, IODP-USIO.
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7
Jpnese rser rn vesse Chkyu. int
eorts ocuse on the Nnk Trouh o the
cost o southestern Jpn, n re wth
on hstory o re erthqukes n ev-
sttn tsunms. an upcomn expeton
w ocus on the octon o the ret Tohoku
erthquke o Mrch 2011.
History o Arc Volcanism
Scentsts hve ne new nsht nto the
hstory o vocnc rcs by stuyn yers o
vocnc sh preserve n ocen sements.
Cores extrcte rom the Mrn-izu rc n the
Western Pcc Ocen yee nery com-
pete 45 mon-yer recor o rc vocnsm,
provn nsht nto how the rc evove over
tme. Other sh stues, rom cores obtne on
the Crbben Pte, ocument the epsoc n-
ture o exposve vocnsm n Centr amerc
n ncte tht some vocnc eruptons n ths
reon rv the rest super-eruptons n the
eooc recor.
Large Igneous Provinces
lre neous provnces orm when mssve
outpourns o bstc v occur over eo-
ocy short tme peros (2-3 mon yers),
cretn sncnty thcker thn norm ocen
crust. lre neous provnces n the ocen re
enery rete to mnte pumes or hotspots
n cn cover tens o thousns o squre ko-
meters. Ther ormton nfuences ocen chem-
stry n cmtc contons, n cn even -ect speces extncton n evouton.
Becuse re neous provnces re so thck
n re oten bure beneth mrne se-
ments, smpn them presents sncnt
chene. our submrne re neous prov-
nces hve been re to te, wth cores
rechn tens to hunres o meters nto the
vocnc rock. Peces o woo n sement
bure n the v revee tht the Kerueen
Pteu n the southern inn Ocen wsonce bove se eve, whe rn on the
Pcc Ocens Onton Jv Pteu suest-
e t orme entrey beneth the se surce.
By tn r cores rom the North atntc
Vocnc Provnce, scentsts were be to cor-
rete the tmn o the erupton tht crete
tht re neous provnce wth the Peocene-
Eocene Therm Mxmum (PETM), pero o
rp ob wrmn bout 55 mon yers
o. Ths correton n tme sueste
connecton between mssve vocnc
eruptons n the chnes n cmte, mss
extnctons, n ocen nox events thtoccurre t the PETM.
Global locations o large igneous provinces. Credit: Modied rom Con et al., 2006.
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Heat Flow, Fluid Flow, andGeochemistry
The sce n mportnce o fu fow throuh
ocen crust cnnot be unerestmtethe
voume o fu fown throuh the ocenc
crust s o the sme orer o mntue s the
mount o wter entern the ocen rom
the wors rvers. However, unt recenty, tte
ws known bout the pthwys o het n
fu throuh the subsefoor. Scentc rn
proves wnow on the mny chemc, tec-
tonc, booc, n eophysc processes
nfuence by the nterctons between wter
n rock. These ncue the mntue n
strbuton o fu pressures, the enerton o
exposve vocnsm, the ormton o hyrtes
n mner resources, n the strbuton o
mcrob communtes. in ton, scentc
ocen rn hs spurre the eveopment
o new smpn technooes n on-term
mesurements tht hep reserchers montor
rtes n ptterns o fu fow.
Fluid Flow Through BasementRock
in ery experments, scentsts notce tht
sewter ppere to be rwn own nto the
fluids, flow, and life
Beneath the oCean floor
BENEaTH THE SEalOOR, ntur pumb-
n system ows fus to crcute throuh
the ocen crust. These fus remove het rom
Erths nteror, ter the chemstry o the bse-
ment rock, n nfuence the strbuton o m-
crobes n the subsurce bosphere. The bty
to r eep nto the sefoor hs ncrese our
unerstnn o the roe o fu fow wthnocen sements n bsement rock, espe-
cy how hyroeooc systems re con-
necte wthn the ocen crust. Ths hs e to
chevements n unerstnn how rock n
fus nterct, how hyrotherm vent systems
crete sefoor mner eposts, n how s
hyrtes re orme. By provn the ony c-
cess to the subsefoor bome, scentc
ocen rn hs so revoutonze
unerstnn o subsurce m-
crob communtes vn t the
mts o e.
Microbes that colonized chips o
basalt placed in a borehole
are visualized using green and
orange fuorescent dyes.
Credit: Beth Orcutt, BigelowLaboratory or Ocean
Sciences.
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9
upper eves o bst throuh r hoes. Ths
ncte tht ocenc crust ws more perme-
be thn the sement yers bove. anyss
o ocen rn cores conrme ths hypothe-
ss, shown tht show bsement rock s con-
sstenty three to seven tmes more permebe
thn the sement eposte bove. urther
stues o rock cores emonstrte tht bse-
ment rock becomes ess permebe t reter
epths beow the ocen foor. The wespre
nture o re-sce fu crcuton throuh
bsement rock hs mpctons or subsefoor
mcrob communtes n or the exchne o
chemcs n het throuh the ocens.
Hydrothermal Vent
Processes
Sewter enters ocenc crust ner m-
ocen res throuh rctures n the rock.
as t penetrtes more eepy nto the crust,
the sewter rects wth the hot bsement
rock n exchnes chemc eements.
Mnesum, or exmpe, s bsorbe nto
the rock, whe
ron, znc, mn-
nese, n copper
re reese nto the fu.
The cc, mner-rch fu be-
comes buoynt n schres t the sefoor.
Chemcs n the hyrotherm fu prove
enery to support ecosystems teemn wth
exotc vretes o shrmp, cms, tubeworms,
n other cretures.
Unt the vent o ocen rn, the ony wy
to stuy the chemc rectons beneth hy-
rotherm vents ws by coectn the fus
emntn rom vents, exmnn rocks rom
the sefoor surce, or stuyn ophotes
rments o ocen crust tht hve been
thrust onto contnents by cosons between
ocen n contnent ptes. Stuyn cores
obtne throuh scentc ocen rn hs
me crtc contrbutons to unerstnn
the chemstry, eooy, n booy o hyro-
therm vents n ther roe n the composton
o ocen crust n ocen chemstry.
Mineral Deposits
One o the more unexpecte outcomes o
rn t hyrotherm stes hs been the s-
covery o mssve sefoor n subsefoor
mner eposts. drn nto re epost
A thin sliver o pyrite
(iron sulde) rom a
hydrothermal mound on
the Mid-Atlantic Ridge.
Credit: IODP-USIO.
Microbiology samples are collected rom a sediment core.
Credit: John Beck, IODP-USIO.
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hve ente mcrobes t ever reter
epths, even nn them n sements co-
ecte t reter thn 1,600 meters beow the
sefoor ner Newounn. Bse on the v-
rety o mcrob e observe so r, scentsts
estmte tht the number o mcrobes vn n
just the top 500 meters o sefoor sement s
equvent to 10 percent o the bomss tht
ves on Erths surce.
Lie Within Earths Crust
Whe most normton on subsurce mcro-
b communtes hs come rom sement
cores, n the te 1990s, scentsts becme
ntereste n mcrob ctvty n the bstc
ocen crust. The ocen crust beneth thesement s potenty the rest hbtt on
Erth, s the voume o ocen crust cpbe
o sustnn e s comprbe n mntue
to the voume o the wor ocen. Ocen r-
n core smpes show tht mcrobes py
n mportnt roe n tern bst rock n
A microbiologist works on core samples in an anaerobic chamber to prevent contamination.
Credit: William Craword, IODP-USIO.
ner the M-atntc Re revee most 3
mon tons o sue. at Me Vey, octe
n the northest Pcc Ocen, scentsts oun
subsurce epost o most 16 percent cop-
per ore. These nns hve enerte nterest
n mnn subsefoor hyrotherm systems,
but there s st much to be erne bout the
ormton n evouton o these eposts.
Thereore, communcton between scentsts
n nustry w be neee to vo potent
envronment me rom ocen foor mnn.
The Subseafoor
BiospherePeope hve on known tht the ocen
hrbors verse rry o speces, but
the mcrob e tht thrves beneth the
sefoor s much more recent scov-
ery. Scentsts rst ente subse-
foor e n 1955, when bcter
were scovere n mrne
sement cores re
7.5 meters beneth
the sefoor. Snce
then, reserchers
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exchnn nutrents between sewter n
the crust. Sever recent scentc expetons
hve ocuse on rn nto bst n usn
CORKs s subsefoor mcrob observto-
res to exmne the unque bosphere present
wthn the bsement rock.
Gas Hydrates
at the hh pressure n ow tempertures
o the eep ocen, ses such s meth-
ne n crbon oxe cn combne wth
sewter to orm n ce-ke crystne
substnce ce s hyrte. Methne hy-
rtes re most oten oun t contnent
mrns, where they re sometmes concen-trte enouh to be consere s potent
enery resource (thouh there re presenty
no methos to economcy extrct them).
Hyrtes re so o nterest becuse scen-
tsts thnk tht the ntur reese o meth-
ne, potent reenhouse s, rom hyrtes
What Can Deep -Sea
MiCrobeS tell US
aboUt the liMitS
of life?
Themicrobesthatdwellbeneaththeseaoor
live in some of the harshest conditions on Earth.
Light cant penetrate to these depths, so most
energy comes from chemical compounds
leached from rock. Deeper beneath the ocean
oor,nutrientsbecomemorescarceandtemperature increases. Understanding how
deep-dwelling microbes can survive at
these depths could help scientists learn
more about the limits of microbial life,
the role of marine microbes in essen-
tial biogeochemical cycles, and the
origin and evolution of life
on Earthand perhapsother planets.
cou poten-
ty contrbute
to cmte wrm-
n. Scentc rn
hs pye mjor roe
n mprovn unerstnn
o the strbuton o s hyrtes
n ocen sements, s we s hyrte
behvor n stbty uner erent temperture
n pressure remes.
Developing Technologies to StudyGas Hydrates
at tmospherc pressure, s hyrte s stbe
ony t tempertures beow -80 C. Thereore,
much o the s hyrte n ocen rn
cores s ost s the core s brouht to the sur-
ce. The scentc ocen rn communty
poneere new technooes, such s the pres-
sure core smper, or recovern n nyz-
n s hyrte eposts t ntur, hh pres-
sure contons.
A chunk o gas hydrate recovered about 6 meters below the seafoor along the
Cascadia margin. Credit: IODP-USIO.
Top Let: This scanning electron microscope image shows microbes that colonized
chips o pyrite placed in a borehole on the Juan de Fuca Ridge fank or 4 years
(2004-2008). Credit: Beth Orcutt, Bigelow Laboratory or Ocean Sciences.
Bottom let: Communities o subseafoor microbes grow on polished chips o basalt
and pyrite placed into a CORK. The microbes can then be visualized using scanning
electron microscopy or fuorescent dyes (above and page 8). Credit: Beth Orcutt,
Bigelow Laboratory or Ocean Sciences.
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12
sheet rowth n copse, s we s ob
se eve fuctutons o up to 120 meters, re-
mns one o the most unment scover-
es o scentc ocen rn.
Past Warm Climate
Extremes and the
Greenhouse World
More thn 3 mon yers o, cmtes were
enery wrmer thn toy n the tmo-
sphere contne hher crbon oxe eves.
By stuyn wrm cmte extremes recore
n ocen sements, scentsts cn ern how
the Erth system respone to peros o e-
evte reenhouse s eves n the pst.
Developing a Timeline o PastTemperatures
Ocen rn recors hve mprove estmtes
o Erths cmte senstvty to hher eves o
reenhouse ses n to short-ve perturb-tons n the crbon cyce. They hve so hepe
scentsts etermne the senstvty o ce sheets
to eevte reenhouse s concentrtons.
Se surce tempertures reconstructe rom
r cores emonstrte tht the ery Eocene
earths Climate historyTHE SEalOOR HOldS eooc rchve
o Erths cmte hstory tht extens or tens
o mons o yers, provn crtc nshts
nto the ptterns n processes o pst cmte
chne. Ths normton proves reserch-
ers wth recors o ntur vrbty nst
whch present n uture cmte chne cn
be compre.
as the enth n quty o scentc ocen
rn recors hs mprove, they hve
contrbute to unerstnn rmtc n
contnuous chnes o the Erths cmte
over the pst 100 mon yers, rom co
peros wth mssve contnent ce
sheets to extreme wrm peros
when por reons were
ce-ree. The entcton
o orbt cyces tht
nfuence repete
cyces o por ce
This thin section o limestone contains numerous shell ragments and small pieces
o volcanic glass that can provide inormation about past climate conditions.
Credit: IODP-USIO.
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Epoch (rom 55 to 48 mon yers o) h the
wrmest cmtes o the pst 65 mon yers,
n tht the wor ws wrmer by bout 10 to
12 C. Cores recovere rom scentc ocen
rn so show tht hh ttues recte
more strony to ncreses n tmospherc
crbon oxe thn res coser to the equtor.
Observtons o pst peros o extreme
wrmth re mportnt becuse they hep
shrpen the perormnce o cmte moes nresponse to hher eves o tmospherc cr-
bon oxe.
Cenozoic Ice Sheet
Evolution and GlobalSea Level Change
Chnes n se eve refect how ce sheets n
the antrctc n the Northern Hemsphere
hve rown n shrunk over tme. Stues
Scientists sample layers o sediments rom cores extracted o the
Antarctic coast. Analysis o these samples will help scientists understand
changes in ocean temperature, sea ice extent, and primary productivitythroughout the last 12,000 years. Credit: Rob McKay, Victoria University
o Wellington.
proxy reCorDS in
SCientifiC oCean
Drilling
Scientistsusedierentcomponentsofmarine
sediments as climate proxiesindicators of
past climate and ocean conditions. For
example, variations in the types of fossilized
plantandanimalspeciesfoundinseaoor
sediment can indicate past changes in environ-
mentalconditionsataspeciclocation.Fossils
can also indicate the age of the various sediment
layers, helping scientists determine when environ-
mental changes took place. Geochemical
measurements of fossilized shell material can
provide insight into past oceanographic conditions,
such as temperature, salinity, pH, and the concen-
tration of atmospheric carbon dioxide. Combining
physical measurements of past temperatures withchemical measurements indicating atmospheric
carbon dioxide concentrations has been
particularly valuable for understanding how the
climate system responds to changes in atmospheric
carbon dioxide levels.
Photomicrographs o oraminiera, single-celled marine organisms that produce
calcite or aragonite shells. The shells can be used as climate proxies and can provide clues to
past ocean ecology and biogeography. Credit: Mimi Katz, Rensselaer Polytechnic Institute.
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o sement cores ccesse throuh ocen
rn hve revoutonze unerstnn o
Erths cmte system urn the CenozocEr (65.5 mon yers o to the present),
n hve mprte new nshts nto the be-
hvor o por ce sheets n ther nfuence
on ob se eve. Becuse the behvor o
ce sheets n the ob cmte system n
wrmn wor s currenty not we uner-
stoo, ocen rn recors cn prove
nos tht hep mt the uncertnty roun
projectons o uture se eve rse.
Understanding Polar Ice Sheets
Scentc ocen rn pye n nter roe
n unerstnn the ntton o antrctc
cton, whch mrke Erths trnston
rom wrmer to coer cmte system.
Cores coecte rom the antrctc contnen-
t she bout 40 yers o prove the rst
evence tht contnent cton extene
bck to the Eocene-Oocene bounry (33mon yers o). Ths sprove the then-
prevn hypothess tht antrctc h
been extensvey cte ony snce the
bennn o the Quternry Er (2.588 mon
yers o).
in 1987, ocen rn on contnent
sheves prove the rst rect evence o
contnent-sce ce sheets cvn t the
paSt CliM ate Change :
the paleo Cene -eoCe ne
therMal MaxiMUM
Extreme changes recorded in the carbon chemistryof oceanic fossil shells indicate that about 55.8 mil-
lion years ago Earth experienced a sudden release
of carbon dioxide into the atmosphere, causing
temperatures to rise by about 4 to 8 C globally in
less than 10,000 years. Because of the timing, which
occurred between the Paleocene and Eocene epochs,
this event is referred to as the Paleocene-Eocene
Thermal Maximum (PETM).
The disruption to the carbon cycle produced
widespreadoceanacidicationandalteredthedeep
oceanecosystem.Bystudyingscienticoceandrilling
cores, scientists found that many species of benthic
foraminifera (single-celled organisms that live in the
deep sea) became extinct during this time. Piston cores
recoveredin2003fromtheSouthAtlanticrstdocu-
mented the size of the PETM carbon release3,000
gigatonsand the subsequent, several hundred
thousand year recovery of ocean chemistry that fol-
lowed the disruption. The PETM is the best analog
of rapid changes in atmospheric carbon dioxide found
to date in the geologic record.
56.055.555.054.554.0
Age (millions of years ago)
3.0a
b
c
2.0
1.0
0
1.0
2.0
13C()
18O()
1.0
1.0
0.5
0
0.5
14
12
10
8Temperature(C)
0
20
40
60
80
100
CaC
O3(%)
1262 (4.8 km)
1263 (2.6 km)
South Atlantic
(water depth)
690
865
525
527
Southern Ocean
Central Pacific
South Atlantic
A rapid increase in carbon isotope ratios in ossilized shells o seafoor organisms collected at
Antarctic, south Atlantic, and Pacic Ocean drill sites indicates a large increase in atmospheric
methane and carbon dioxide during the PETM (top panel). This occurs at the same time as 5 Co global warming (middle panel, presented with oxygen isotope values). Ocean acidication that
ollowed the PETM is indicated by a rapid decrease in the abundance o calcium carbonate (lower
panel). Credit: Zachos et al., 2008.
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Changes in global sea level, atmospheric carbon
dioxide concentration, and temperature over the past
55 million years ago, reconstructed rom scientic
ocean drilling data. (A) The global sea level curve
represents changes in sea level in response to
fuctuations in polar ice volume. (B) Dramatic
variability in atmospheric CO2
concentrations (shown
in green) are recorded in shells and other organic
biomarkers preserved in ocean sediments. (C) Changes
in global temperature are shown with oxygen
isotopes derived rom seafoor organisms, representing
global ice volume and deep ocean temperatures.
Credit: Modied rom R. Levy, GNS Science.
A Pleistocene ossil
brittle star ound in a
core sample. Credit:
IODP-USIO.
antrctc costnebrekn o n chunks
s they meet the ocen. urthermore, ce-
rte ebrssements tht becmetrppe n ce n eposte on the ocen
foor when the ce metecoecte n the
Southern Ocen ncte tht the antrctc
ce sheet rew qucky (wthn ew tens o
thousns o yers) n cuse rop n
ob se eve o t est 60 meters.
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oxygen iSotopeS
Naturally occurring oxygen (O) exists in nature in the form
ofthreedierentisotopes(16O, 17O, and 18O)atoms with
the same number of protons and electrons but with
dierentnumbersofneutrons.Changesintheratio
between 16O and 18O are related to temperature varia-
tions, changes in evaporation and precipitation, and
the amount of Earths water that is locked in ice
sheets. In the shells of microscopic marine organ-
isms, this ratio acts as a chemical signature that
reveals information about the temperatures
that existed when the organisms were alive.Paleoceanographers use these records to
create a temperature timeline that
extends back millions of years,
providing information about the
extent of glaciations and
Earths ancient climates.
in 1981, scentc ocen rn contrbute to
mjor ncrese n unerstnn these vr-
tons, when n most contnuous sementrecor ws recovere rom the hh-ttue
atntc Ocen. at ths ste, scentsts showe
tht chnes n oxyen sotope rtos (see
box t et.) were correte wth ncreses n
ce-rte ebrs, provn entve evence
tht contnent ce sheets h exste nerby.
Ocen rn estbshe the rst e or the
onset o mjor contnent ctons, bse
on observtons tht ony sm mounts o
ce-rte ebrs were oun n cores beore
ths tme.
Understanding Global Sea LevelChange
Ocen rn on the estern North
amercn contnent mrn hs prove
100 mon-yer recor o ob se eve
chne, own scentsts to enty bure
eroson surces tht correte wth tmeswhen se eve e n nterrupte sement
in contrst to the ery successes n the
antrctc, unerstnn the arctcs c
hstory took r oner. in the m-2000s,
strtey tht combne r shps wth ce-brekers cpbe o rechn remote, ce-cov-
ere res succeee n cpturn 55 mon
yer hstory o cmte chne n the centr
arctc Ocen.
Glacial and Interglacial Cycles
The tme pero between 3 n 2.5 mon yers
o sw ob coon n the expnson o
contnent ce n the Northern Hemsphere.
Ths coon tren ntte seres o c
n nterc cyces controe by on-term
vrtons n Erths orbt.
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17
eposton. Reserchers were be to nk
these nstnces o se eve wth rowth o
the por ce sheets. More thn 30 osctons
n ob se eve urn the Oocene n
Mocene Ers (33 to 6 mon yers o) were
ente.
Recent expetons hve so successuy
re cor rees n crbonte rocks n Tht
n the gret Brrer Ree n austr. TheTht expeton recovere exceent recors
o the st nterc pero (bout 125,000
yers o), when ob se eve ws re-
tvey hh, n o the rp se eve rse snce
the st ce e. These t prove crtc
constrnts on pst se eve hh stns n
hepe qunty the rte o se eve rse.
Orbital Forcing
The stuy o cmte vrbty ue to
chnes n Erths orbt proves one o the
best exmpes o n emern e row-
n exposvey becuse o scentc ocen
rn. in 1979, new corn technooy pro-
uce the rst on, unsturbe recors o
mrne sement, own scentsts to exten
the tme seres o mrne oxyen sotopes
bck 3.5 mon yers. Expetons n the ery
1980s expne the knowee o c-
nterc cyces, the tmn o Northern
Hemsphere ctons, n the chnn n-
ture o the cmte system n response to or-
bt orcn (see box on Mnkovtch cyces,
p.18). Bse on these ery successes, 16-
yer, ob-sce eort to observe n stuy
orbty-orce cmte throuhout tropc n
hh-ttue octons o ocen bsns ws
ntte. These es represente mjor e-
ort, n ts successes re mon the most
sncnt or the ocen rn communty.
The sements coecte throuh scentc
Coral ree and carbonate rocks drilled rom Australias Great Barrier Ree provide insight into the rapid
sea level rise o the last ice age. Credit: European Consortium or Ocean Research Drilling (ECORD)/IODP.
A sediment core rom the eastern Mediterranean Sea demonstrates cyclicity
related to orbital orcing. The alternating layers o dark-colored sediments,
which are rich in organic matter, and light-colored carbonate ooze are due
to changes in the North Arican monsoon pattern. Credit: IODP-USIO.
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Abrupt Climate Change
in the m-1980s, scentsts observe tht cecores rom greenn recore seres o
rp n brupt chnes n r temperture
over menn (thousn-yer) tme sces.
Hypotheszn tht nterctons between the
ocen n tmosphere were responsbe or
ths phenomenon, reserchers ocuse on
rp chnes o the North atntc Ocens
re-sce crcuton, whch s rven by -
erences n temperture n snty between
the ocens surce n ts epths. Scentc
ocen rn pye mjor roe n rpy
vncn the knowee o these shorter-
sce temperture swns, rst throuh theuse o exstn cores rom pst rn es n
ter throuh trete smpn opportuntes
cross the obe. These t hve so been
use s nepenent conrmton o the re-
bty o cmte moes.
Co-Evolution o Lie and
the Planet
The presence o e on Erth moes pne-
try processes, ectn the composton n
propertes o the tmosphere, hyrosphere,n the so Erth. The ocen s n ctve
contrbutor to Erth system processes n
so serves s repostory o sements tht
recor chnes n ocenc e. Ocen rn s
the best wy to ccess ths recor n prstne
MilankovitCh
CyCleS
CyclesintheEarthsorbitinuencethe
amountofsunlightthatreachesdierent
partsoftheEarthatdierenttimesofyear.In
the early 20th century, Serbian geophysicist and
civilengineerMilutinMilankoviproposedatheory to explain how these orbital changes could
explain the history of Earths ice ages. His work
explored how the Earths orbital cyclesincluding
the direction (23,000 year period) and tilt (42,000
year period) of the Earths axis, and the shape of its
orbit(100,000yearperiod)hadlong-termeectson
climate, including the timing of glacial and intergla-
cial cycles. Collectively, these cycles are known as
Milankovitchcyclesandtheireectsareknownas
orbital forcing.
ocen rn hve rety vnce the un-
erstnn o orbt cmte vrbty n
ts cuses, n hve prove scentsts wth rmework n tme sce to nterpret the
resuts o stues rom we rne o sc-
pnes, rom the eoscences to rcheooy,
nthropooy, n stronomy. By coectn
n nyzn on, hh resouton recors, re-
serchers hve been be to construct bue-
prnt o mny processes tht ecte Erths
cmte n the stnt pst. Reconton o the
wespre mpct o orbt orcn on cmte
chne hs been mjor outcome o scentc
ocen rn.
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orm n wth hh eve o et, n hs en-
hnce stues o e processes on the pnet.
Mny scentc ocen rn projects hve
nvove bostrtrphy, whch s the pro-
cess o corretn n ssnn retve
es o rock or sement usn the osss
contne wthn them. in ton, ocenc
osss cn be use to etermne reon
n ob ecooc or chemc chn-
es. Usn ths recor, scentsts cn n
nsht nto the resons behn chnn
ptterns o e on Erths surce, n hve
been be to eveop new concepts o the
retonshps between evouton, extncton,
n chnes n cmte.
Documenting Asteroid andMeteorite Impacts
in 1980, tem o reserchers oun hh
concentrtons o rum n sement yer
t the 65.5 mon yer o bounry between
the Cretceous n Peoene peros (K-P,
ormery K-T bounry), the sme pero
s mss extncton o nery 75 percent
o the wors speces. irum s n
extremey rre chemc eement n the
Erths crust, but s oun n steros n
Scientic ocean drilling has helped reconstruct past climatic conditions that are relevant or the study o human evolution. (A) shows the timing o hominin evolution, including the rst appearances
o stone tools. In (B) and (C), this is correlated with sediment cores that mark wet and dry cycles related to the North Arican monsoon (a more detailed view can be seen on page 17) and sedimentary
evidence o deep lake conditions in East Arica. (D) and (E) use carbon isotopic analyses o plant biomarkers rom scientic ocean drilling and o soil carbonate nodules to indicate the expansion o
savannah grassland ater 3 million years ago. This is supported by (F), an increase in the relative abundance o Arican mammals that are adapted to graze in the grassland. Credit: DeMenocal, 2011.
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20
comets, en to the hy-
pothess tht n stero h
struck Erth n cuse mss extncton.
Scentsts stue exstn ocen
rn cores to ocument the
ob strbuton o the rum
nomy n ejecte prtces
rom the stero mpct, the
eects on mrne ecosystems,
n the octon o the ster-
o mpct. Smpn o cores
urn ter ocen rn es
prove urther evence or
the rum nomy n mssextncton o mrne ornsms
t the K-T bounry, emon-
strtn the ob strbuton o
these phenomen.
A sediment core across the boundary
between the Cretaceous and Paleogene
periods, known as the K-T boundary. An
asteroid impact is recorded in the dark layer
in the middle o the core record, which is
composed o ejected material. A thin
layer o orange-colored extraterrestrial
material lies above the ejecta. The lighter
layers o sediment above and below the
ejecta contain ossils o ocean micro-
organisms and demonstrate signicant
shits in the type o communities beore
and ater the impact. Credit: IODP-USIO.
Hominin Evolution
Mrne sements ho contnuous n e-
te recors o Cenozoc cmte chne n
speces strbuton. Recovery o these recors
throuh scentc ocen rn hs prove
envronment context or expntons o bo-
oc chnes on the contnentsespecy
the evouton o ery humns n arc. or
exmpe, mrne sement cores re n the
inn n Southern atntc Ocens contn
ust tht swept cross the arcn contnent,
provn evence o fuctutons n arcs
pst cmte. Usn ocen rn recors n
concert wth ke n contnent r cores,
scentsts hve oun tht mjor steps n the
evouton o arcn homnns n other verte-
brtes occurre wth shts to more r, open
contons t specc tmes urn the pst 2.8
mon yers. Ths correton hs strenthene
the nks between humn orns n ther en-
vronment context.
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aS THE CURRENT ocen rn prorm
rws to cose n 2013, scentsts, eer
ences, n nternton prtners re -
rey pnnn or the next prorm. Prt o the
pnnn ncue re nternton meet-
n o scentsts, whose thouhts n su-
estons were the bss or rtn scencepn or the propose 2013-2023 scentc
ocen rn prorm. The resut, the Nton
Scence ountons Illuminating Earths Past,
Present, and Future: The International Ocean
Discovery Program Science Plan or 2013-
2023, ws compete n June 2011.
One o the mjor premses o the scence pn
s tht scentc ocen rn hs the poten-
t to contnue enbn essent vnces
n mutpe scentc es, s t hs one n
pst prorms. The scence pn ocuses on
the vue o Erth scence knowee to meetsocet chenes n support better ec-
son mkn.
The scence pn s ve nto our reserch
themes: (1) Cmte n Ocen Chne, (2)
Bosphere ronters, (3) Erth Connectons,
n (4) Erth n Moton. Wthn these themes,
there re 14 specc chenes, or specc
reserch questons. The Nton Reserch
Counc commttee ws ske to ssess the
potent or trnsormtve scentc scovery
rete to the themes n chenes wthn
the scence pn.
assessment of the2013-2023 sCienCe Plan
Illuminating Earths Past, Present, and Future: The International Ocean
Discovery Program Science Plan for 2013-2023, the National Science
Foundations plan or the proposed next phase o scientic ocean drilling,
was published in June 2011. Credit: NSF.
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Themes and Challenges rom IlluminatingEarths Past, Present, and Future
The internton Ocen dscovery Prorm
Scence Pn or 2013-2023
Theme 1 - Cmte n Ocen Chne: Ren the Pst, inormn the uture
1. How does Erths Cmte System Respon to Eevte leves o atmospherc CO2?
2. How do ice Sheets n Se leve Respon to Wrmn Cmte?
3. Wht Contros Reon Ptterns o Precptton, such s those assocte wth
Monsoons or E No?
4. How Resent s the Ocen to Chemc Perturbton?
Theme 2 - Bosphere ronters: deep le, Boversty, n Envronment
orcn o Ecosystems
5. Wht re the Orn, Composton, n gob Sncnce o SubsefoorCommuntes?
6. Wht re the lmts o le n the Subsefoor?
7. How Senstve re Ecosystems n Boversty to Envronment Chne?
Theme 3 - Erth Connectons: deep Processes n Ther impct
on Erths Surce Envronment
8. Wht re the Composton, Structure, n dynmcs o Erths Upper Mnte?
9. How re Sefoor Spren n Mnte Metn lnke to Ocen Crust
archtecture?
10. Wht re the Mechnsms, Mntue, n Hstory o Chemc Exchnes Between
the Ocenc Crust n Sewter?
11. How do Subucton Zones intte, Cyce Votes, n generte Contnent Crust?
Theme 4 - Erth n Moton: Processes n Hzrs on Humn Tme Sces
12. Wht Mechnsms Contro the Occurrence o destructve Erthqukes, lnses,
n Tsunm?
13. Wht Propertes n Processes govern the ow n Store o Crbon n
the Sefoor?
14. How o us lnk Subsefoor Tectonc, Therm, n Boeochemc Processes?
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Recommendation: The scientifc ocean drill-
ing community should establish a mechanism to
prioritize the challenges outlined in the scienceplan in a manner that complements the existing
peer-review process.
The commttees nyss o the pst sc-
entc ocen rn prorms oun hs-
tory o mkn exceent use o ecy sm-
pes n t, whch hve hepe to qucky
vnce new res o reserch. The scence
pn s justby ocuse on the mportnce
o uture rn chenes n oes not
expcty ocus on the use o ecy norm-
ton n smpes.
Over, the commttee oun tht the scence
pn presents stron cse or the contnu-
ton o scentc ocen rn, cery en-n ts possbe benets to scence n soc-
ety. in prtcur, stues o the subsefoor
bosphere present opportuntes to enty
mcrobes tht cou be useu to humns,
n contnun stues o pst cmte cou
prove nsht nto the ob n reon c-
mte chne precte or the uture. in -
ton, smpn eeper nto the ocen crust
cou e to better unerstnn o eep
Erth processes, especy technooc
vnces ow more ntct cores to be recov-
ere n expn n stu montorn o ctve
tectonc processes.
Ech o the our themes wthn the scence
pn entes compen chenes wth
potent or trnsormtve scence tht cn
ony be resse by scentc ocen rn.
Some chenes wthn these themes pper
to hve reter potent or trnsormtve sc-
ence thn others.
The commttee etermne tht the
themes n chenes ente n the
scence pn re pertnent n we-jus-
te, thouh there s tte unces to whch o the 14 chenes re
most mportnt. in tmes o thter
scence buets, the scentc
ocen rn communty my wsh
to urther prortze possbe uture
rn objectves.
Cores, packed in tubes, are stored in the
core repository. Credit: IODP-USIO.
23
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Technooy hs hepe py vt roe n
chevn mny scentc vnces n prev-
ous scentc ocen rn prorms. Thecommttee oun tht trnsormtve scence
s crtcy epenent on technooc brek-
throuhs, concun tht ny uture scent-
c ocen rn prorm shou contnue to
push the technooc enveope.
Recommendation: Pathways or innovations in
technology should be encouraged. In addition,
setting aside a small portion o scientifc ocean
drilling resources specifcally to promote techno-
logical research and development could greatly
increase the potential or groundbreaking science.
Usn ecy t n smpes to ther mx-
mum cpbtes w contnue to ncrese
the scentc vue o the scentc ocenrn prorms. Expne use o ecy m-
ters cou hep, or exmpe, wth prortz-
ton o rn objectves n the next phse o
ocen rn.
athouh sever ntur ponts o synery
between chenes n themes re we e-
scrbe, the commttee et tht the scence
pn wou hve been strenthene by more
ete exmnton o res o overp
between n mon the scence chen-
es, whch cou hep use resources more
eectvey. or exmpe, ntertn mu-tpe rn objectves n the ery pnnn
stes o expetons wou mxmze
scentc output n reton to costs. There my
be opportuntes or scentc ocen rn
to urther evove exstn pproches to
ntertn mutpe objectves nto sne
expeton.
Recommendation: From the earliest stages o
proposal development and evaluation, pos-
sibilities or increasing program efciency
through integration o multiple objec-
tives into single expeditions should
be considered by proponents and
panels.
Close-up o a drill bit used in scientic
ocean drilling. Credit: Johan Lissenberg,
Cardi University & IODP-USIO.
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This booklet was prepared by the National Research Council based on the report Scientific Ocean
Drilling: Accomplishments and Challenges from the Ocean Studies Board. The project was spon-
sored by the National Science Foundation.
More information about the report is available at www.dels.nas.edu or by
contacting the Ocean Studies Board at (202) 334 2714. To download a free
PDF of the report or purchase a hard copy, please visit the National Acad-
emies Press website at www.nap.edu or contact the National Academies
Press at (800) 624 6242.
FIGURE AND CHART SOURCES:
Page 3, modified from Fisher, A.T., C.G. Wheat, K. Becker, J. Cowen, B. Orcutt, S. Hulme, K.
Inderbitzen, A. Turner, T. Pettigrew, E.E. Davis, H. Jannasch, K. Grigar, R. Adudell, R. Meldrum,
R. Macdonald, and K. Edwards. 2011. Design, deployment, and status of borehole observa-
tory systems used for singlehole and cross-hole experiments, IODP Expedition 327, eastern
flank of the Juan de Fuca Ridge. In Proceedings of the Integrated Ocean Drilling Program 327,
Fisher, A.T., T. Tsuji, and K. Petronotis (Eds.). Integrated Ocean Drilling Program ManagementInternational, Tokyo, Japan.
Page 7, modified from Coffin, M.F., R.A. Duncan, O. Eldholm, J.G. Fitton, F.A. Frey, H.C. Larsen,
J.J. Mahoney, A.D. Saunders, R. Schlich, and P.J. Wallace. 2006. Large igneous provinces and
scientific ocean drilling: Status quo and a look ahead. Oceanography 19(4):150-160.
Page 14, Zachos, J.C., G.R. Dickens, and R.E. Zeebe. 2008. An early Cenozoic perspective on
greenhouse warming and carbon-cycle dynamics. Nature 451:279-283.
Page 19, DeMenocal, P.B. 2011. Climate and human evolution. Science 331(6017): 540-542.
ABOUT THE NATIONAL ACADEMIES
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Engineering, Institute of Medicine, and the National Research Councilprovide a public service
by working outside the framework of government to provide independent advice on matters of
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the nations most significant efforts to improve health, education, and the welfare of the population.
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