The Vegetation of Antarctica through Geological Time

488 Pages·2013·22.02 MB·English

by  David J. Cantrill

THE VEGETATION OF ANTARCTICATHROUGH
GEOLOGICAL TIME
ThefossilhistoryofplantlifeinAntarcticaiscentraltoourunderstandingoftheevolution
of vegetation through geological time, and also plays a key role in reconstructing past
configurationsofcontinentsandassociatedclimaticconditions.Thisbookprovidesthefirst
detailedoverviewofthedevelopmentofAntarcticvegetationfromtheDevonianperiodto
the present day, providing Earth scientists with valuable insights into the break-up of the
ancientsupercontinentofGondwana.
Details of specific floras and ecosystems are provided within the context of changing
geological,geographicalandenvironmentalconditions,alongsidecomparisonswithcontem-
poraneousandmodernecosystems.Theauthorsdemonstratehowpalaeobotanycontributesto
our understanding of the palaeoenvironmental changes in the Southern Hemisphere during
thisperiodofEarthhistory.
Thebookisacompleteandup-to-datereferenceforresearchersandstudentsinAntarctic
palaeobotanyandterrestrialpalaeoecology.
davidj.cantrillisChiefBotanistandDirectoroftheNationalHerbariumofVictoriaat
the Royal Botanic Gardens Melbourne, Australia. Throughout his academic life he has
undertaken extensive work across the Southern Hemisphere, particularly Antarctica,
researching fossil floras from the Permian to early Cenozoic. His research into Antarctic
biotashasconcentratedonthesystematiccompositionoffloras,palaeoecology,theroleof
AntarcticainmediatingclimateandbiogeographicpatternsduringGondwanabreak-up,and
developingpresent-daypatternsofaustralplantdistribution.
imogenpooleisaSeniorResearchFellowatUtrechtUniversityandHonoraryResearch
FellowattheUniversityofAberdeen.Shehasworkedextensivelyonpalaeovegetational,
palaeoenvironmental and palaeoclimatic interpretations of Cretaceous and younger floras
fromboththeNorthernandSouthernHemispheres.Aparticularfocusofherresearchhas
beendeterminingthefloristiccompositionofhighlatitudeAntarcticflorasandreconstruct-
ingthepalaeoenvironmentandclimateoftheseearlyangiospermousecosystems.
Authorship sequence is purely alphabetical as both authors contributed equally to the
compilationofthisbook.
INTERNATIONAL STRATIGRAPHIC CHART
International Commission on Stratigraphy
ICS
EonothemEonErathemEraSystemPeriod SeriesEpoch StageAge AgeMa GSSP EonothemEonErathemEraSystemPeriod SeriesEpoch StageAge AgeMa GSSP
145.5 ±4.0
Holocene Tithonian
y 0.0117 150.8 ±4.0
ar Upper Upper Kimmeridgian
n 0.126 ~ 155.6
er “Ionian” Oxfordian
at Pleistocene 0.781 161.2 ±4.0
u Calabrian Callovian
Q 1.806 164.7 ±4.0
Gelasian c Bathonian
2.588 si Middle 167.7 ±3.5
Piacenzian as Bajocian
Pliocene 3.600 r 171.6 ±3.0
e MZaensscilneiaann 5.332 o i c uJ AToaalercniiaann 175.6 ±2.0
z o i c Neogen Miocene SLTeoarrrnatgovhnaiilaalinann 11371...82624068 e s o z Lower PSHliieenntetsambnaugcrihiaaiannn 111889396...065 ±±±111...550
o 15.97 M 199.6 ±0.6
e n BAuqrudiitgaanliiaann 20.43 Upper RNhoareiatiann 203.6 ±1.5
c C 23.03 c 216.5 ±2.0
o i Oligocene Chattian 28.4 ±0.1 o i sic Carnian ~ 228.7
e r o z ne PBRraiuarpbtoeonlniiaaiannn 3373..29 ±±00..11 e r o z Trias Middle OLAalendniisenikaiaiannn 2~3 274.05 .±92.0
n ge Eocene 40.4 ±0.2 n Lower ~ 249.5
a o Lutetian a Induan
P h Pale Ypresian 4585..68 ±±00..22 P h Lopingian Changhsingian 225513..08 ±±00..47
Thanetian Wuchiapingian
58.7 ±0.2 260.4 ±0.7
Paleocene Selandian Capitanian
~ 61.1 265.8 ±0.7
Danian n Guadalupian Wordian
Maastrichtian 65.5 ±0.3 mia Roadian 268.0 ±0.7
70.6 ±0.6 r 270.6 ±0.7
e
Campanian c P Kungurian
Santonian 83.5 ±0.7 o i Artinskian 275.6 ±0.7
Upper 85.8 ±0.7 z Cisuralian 284.4 ±0.7
M e s o z o i c Cretaceous CBCeTaounAAronrprlobmeitaniimaaacianniniaaniannn 11~99123925 8....66008 .±±±±60011....8900 P a l e o niferous Penn-sylvanian UMLopidwpdeelrer KSMBGaAaaosszkssishmmhceekoaolliviirrvaaiiiiaaannannnn 223339900149371.....60427 ±±±±±00011.....88901
Lower 130.0 ±1.5 o 318.1 ±1.3
Hauterivian b Upper Serpukhovian
VBaelarnrigaisniaiann ~14 103.23 .±93.0 Car Missis-sippian MLoidwdeler ToVurisneaaisnian 334258..33 ±±21..16
145.5 ±4.0 359.2 ±2.5
EonothemEonErathemEraSystemPeriod SeriesEpoch StageAge AgeMa GSSP EonothemEon ErathemEra SystemPeriod AgeMa GSSPGSSA
359.2 ±2.5 542
Famennian Ediacaran
Upper 374.5 ±2.6 Neo- ~635
Frasnian Cryogenian
n 385.3 ±2.6 proterozoic 850
a Givetian Tonian
Devoni Middle EEmifesliiaann 334990177...850 ±±±222...778 rozoic proMteersooz-oic ESctetansiaiann 111024000000
Lower Pragian e Calymmian
411.2 ±2.8 ot 1600
Lochkovian Pr Statherian
416.0 ±2.8 n 1800
Pridoli a Paleo- Orosirian
Ludfordian 418.7 ±2.7 r i proterozoic Rhyacian 2050
Ludlow 421.3 ±2.6 b 2300
n Gorstian 422.9 ±2.5 m Siderian 2500
Siluria Wenlock SHheoinmweoroiadinan 442268..22 ±±22..43 e c a Neoarchean 2800
Telychian r
c 436.0 ±1.9 P n Mesoarchean
z o i o i c Llandovery RAhuedrodnainainan 439.0 ±1.8 chea 3200
o z 443.7 ±1.5 Ar Paleoarchean
P h a n e r P a l e o ovician UMpidpdelre DSHaKairnrnardatiwibaniintlaiiaannn 444465640585....9816 ±±±±1111....6665 HaEodaercahnea (ninformal) 34600000
d Dapingian
Or 471.8 ±1.6 ~4600
Floian
Lower 478.6 ±1.7 Subdivisions of the global geologic record are
Tremadocian formally defined by their lower boundary. Each unit
488.3 ±1.7 of the Phanerozoic (~542 Ma to present) and the
Stage 10
base of Ediacaran are defined by a basal Global
~ 492 *
Furongian Stage 9 Boundary Stratotype Section and Point (GSSP ),
~ 496 * whereas Precambrian units are formally subdivided
Paibian by absolute age (Global Standard Stratigraphic Age,
~ 499 GSSA). Details of each GSSP are posted on the
n Guzhangian
a ~ 503 ICS website (www.stratigraphy.org).
ri Series 3 Drumian Numerical ages of the unit boundaries in the
mb ~ 506.5 Phanerozoic are subject to revision. Some stages
Stage 5 within the Cambrian will be formally named upon
a ~ 510 *
C Stage 4 international agreement on their GSSP limits. Most
Series 2 ~ 515 * sub-Series boundaries (e.g. Middle and Upper
Stage 3 Aptian) are not formally defined.
~ 521 *
The listed numerical ages are from 'A Geologic
Stage 2
Terreneuvian ~ 528 * Time Scale 2004', by F.M. Gradstein, J.G. Ogg,
Fortunian A.G. Smith, et al. (2004; Cambridge University Press)
542.0 ±1.0
and ‘The Concise Geologic Time Scale’ by J.G. Ogg,
This chart was drafted by Gabi Ogg. Intra Cambrian unit ages G. Ogg and F.M. Gradstein (2008).
with * are informal, and awaiting ratified definitions.
Sept. 2010
Copyright © 2010 International Commission on Stratigraphy

THE VEGETATION OF ANTARCTICA
THROUGH GEOLOGICAL TIME
DAVID J. CANTRILL
RoyalBotanicGardensMelbourne
IMOGEN POOLE
UtrechtUniversity,TheNetherlands
cambridge university press
Cambridge,NewYork,Melbourne,Madrid,CapeTown,
Singapore,SãoPaulo,Delhi,MexicoCity
CambridgeUniversityPress
TheEdinburghBuilding,CambridgeCB28RU,UK
PublishedintheUnitedStatesofAmericabyCambridgeUniversityPress,NewYork
www.cambridge.org
Informationonthistitle:www.cambridge.org/9780521855983
©DavidJ.CantrillandImogenPoole2012
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2012
PrintedintheUnitedKingdomattheUniversityPress,Cambridge
AcataloguerecordforthispublicationisavailablefromtheBritishLibrary
LibraryofCongressCataloguinginPublicationdata
Cantrill,DavidJ.,1962–
ThevegetationofAntarcticathroughgeologicaltime/DavidJ.Cantrill,RoyalBotanicGardens
Melbourne,ImogenPoole,UtrechtUniversity,TheNetherlands.
pages cm
ISBN978-0-521-85598-3(hardback)
1. Plants–Evolution–Antarctica. 2. Plants,Fossil–Antarctica.
3. Palaeobotany–Devonian. 4. Palaeoecology–Devonian. 5. Palaeontology–Devonian.
6. Geologicaltime. I. Poole,Imogen. II. Title.
QK980.C35 2012
5610.19989–dc23
2012001241
ISBN978-0-521-85598-3Hardback
CambridgeUniversityPresshasnoresponsibilityforthepersistenceor
accuracyofURLsforexternalorthird-partyinternetwebsitesreferredto
inthispublication,anddoesnotguaranteethatanycontentonsuch
websitesis,orwillremain,accurateorappropriate.
Contents
Acknowledgements pageviii
1 Historicalbackgroundandgeologicalframework 1
2 EarlytomiddlePaleozoicclimatesandcolonisationoftheland 26
3 Collapsingicesheetsandevolvingpolarforestsofthemiddletolate
Paleozoic 57
4 Icehousetohothouse:floralturnover,thePermian–Triassiccrisisand
Triassicvegetation 105
5 Gondwanabreak-upandlandscapechangeacrosstheTriassic–Jurassic
transitionandbeyond 161
6 Fern-coniferdominatedEarlyCretaceous(Aptian–Albian)ecosystems
andtheangiosperminvasion 189
7 Theoriginofsoutherntemperateecosystems 249
8 Theheatison:PaleogeneflorasandthePaleocene–Eocenewarmperiod 308
9 Aftertheheat:lateEocenetoPlioceneclimaticcoolingandmodification
oftheAntarcticvegetation 390
Appendix:CretaceoustoNeogenefossilfloras 458
Index 466
vii
Acknowledgements
Theauthorsareindebtedtoanumberofcolleaguesandfriendswhohaveprovidedinvaluable
helpinanumberofwaysthroughoutthecourseofwritingthisbook.Suchhelpincludedthe
answeringofquestions,providingcopiesof(elusive)publications,allowingaccesstounpub-
lished material, in-depthdiscussions, translating foreign literatureand comments on earlier
draftsofthechapters.TheyparticularlythankProfessorR.Askin,ProfessorK.Birkenmajer,
Professor A. Gaździcki, Professor L. Ivany, Professor B. Mohr, Professor M. Reguero,
Professor E.Truswell,DrR.Carpenter, DrH.Falcon-Lang,Dr R.Hunt, DrV. Thorn, and
particularlyProfessorT.Dutraforherconstantdiscussionsandunyieldingenthusiasmforthis
project.ThestaffattheBritishAntarcticSurvey,UtrechtUniversity(theNetherlands),Leeds
University (England), Naturhistoriska Riksmuseet Stockholm (Sweden), Royal Botanic
GardensMelbourne(Australia)andtheRoyalBotanicGardensKew(England)arethanked
for their help in acquiring relevant data and publications and/or allowing access to
facilities during the course of the original research. Professor David Jolley is thanked
for his encouragement and use of facilities at Aberdeen University during the final stages
of this work. The authors thank the British Antarctic Survey and the British Navy for the
ability to visit many of the sites mentioned in the text between the periods 1992 to 2002.
This work was the product of direct and indirect funding from a number of grants from
NationalEnvironmentalResearchCouncil,NederlandseOrganisatievoorWetenschappelijk
OnderzoekAard-enLevenswetenschappen,SYNTHESYS,andVetenskåpsrådetforwhich
theyareextremelygrateful.Finallytheauthorswouldliketothanktheirspouses,familiesand
friendsfortheirunyieldingsupport,bothmentallyandphysically(especiallyonthedomestic
front),thatenabledthisworktobefinallylaidtorest.
viii
1
Historical background and geological framework
Introduction
TodayAntarcticaisacontinentlockedinicewithnearly98%ofitscurrentterraincovered
bypermanenticeandsnow.YetforthevastmajorityofitsexistencetheAntarcticlandmass
wasice-freeandsupportedadiversityofplantsandanimals.Thehistoryofthevegetationof
Antarctica through geological time is intimately linked with that of the geography and
climate,forbothgeographyandclimatehaveshaped,fashionedandcontrolledthesehigh
latitudeecosystemsovergeologicaltimescales.
Today ice sheet and sea ice processes in Antarctica are key drivers of the oceanic
circulationsystem.TheoceaniccirculationensurestheAntarcticcontinentremainsinhos-
pitabletoterrestrialplantlifethroughextremecold.Yetonageologicaltimescalethecurrent
lack of extensive vegetation is a relatively recent phenomenon, possibly as recent as
Pliocene. During the 300 million years covering the Paleozoic, Mesozoic and Cenozoic
the fossil record reveals evidence of extensive forests across the high latitudes. Moreover
occupying the central component of Gondwana, Antarctica played an important role in
creating present daySouthern Hemisphere biogeographic patterns by providing terrestrial
connectionsbetweenwhataretodaywidelyseparatedlandmasses.Anobviousexampleof
this is the distribution of Antarctic beech (Nothofagus) across South America and the
southwest Pacific, which can be attributed to past terrestrial connections across
Antarctica. The lack of present day terrestrial diversity however makes it difficult to
integratetheAntarcticregionintobiogeographicstudiesthatrelyondeterminingrelation-
shipbetweenextantgroups.ThisfurtheremphasisestheimportanceoftheAntarcticfossil
recordforunderstandingpresentdaySouthernHemispherediversitypatterns.Theinterplay
between supercontinent fragmentation, creation of new oceanic basins and oceanic circu-
lationpatterns,andevolutionoftheclimatesystemallplayedacriticalroleinthehistoryof
Antarcticvegetation.
This book sets out to explore the interplay between geological processes and climate
evolution ontheevolvingvegetation ofAntarctica, butfirst, tosetthe bookinitsrightful
context, we summarise the history of palaeobotanical interest in Antarctica and provide a
briefsummaryofthegeologyofthissouthernmostcontinent.
1
2 The Vegetation of Antarctica through Geological Time
Historyofpalaeobotanicaldiscovery
TodaytheAntarcticregioniseasilydefinedbystrongoceanicandatmosphericfeatures.The
Antarctic Circumpolar Current, a feature observed by early explorers, effectively isolates
cold surface waters of the Southern Ocean from warmer waters further to the north. The
dramaticchangeintemperatureoverashortdistanceinsurfacewaters(termedtheAntarctic
Convergence)isamajorbiogeographicfeaturethatsupportsdifferentassemblagesofmarine
organismseithersideoftheconvergence(Arntz,GuttandKlages,1997;Linseetal.,2006).
AlthoughtheAntarcticregiontodayisdefinedbythesepresentdayoceanographicfeatures
theyhavenotalwaysbeenpresent.Nevertheless,theAntarcticCircumpolarCurrentbroadly
formsaconvenientboundarytodiscusstheearlyscientificexpeditionsofthesouthernhigh
latitudesincludingtheearlyvoyagesofHalley(1699–1700)andCook(1772–1775)–both
ofwhichpenetratedthesouthernpolarregionsyetfailedtodiscoverland.
Cookmadeseveralforaysintothehighlatitudesinanattempttodiscoverlandbutwhile
unsuccessful,hisrecordsplayedanimportantroleineliminatinglargetractsoftheSouthern
Ocean from further exploration. These exploratory expeditions paved the way for the
discovery of the continent. The voyages of Cook provided dismal descriptions of the
southernpolarregionsdepicting themsimplyasafrozenwasteland.Despitethis,whalers
andsealerscontinuedtopushfurthersouthintothesouthernhighlatitudesdrivenonbythe
depletionofsealingandwhalinggroundsfurthernorth.Thereforeitisnosurprisethatsealers
areacknowledgedasbeingthediscoverersofseveraloftheAntarcticislands(e.g.Macquarie
IslandbyF.HasselburghaboardthePerserverance;Fogg,1992),includingthoselyingoff
theAntarcticPeninsula(e.g.SouthShetlandIslandbyWilliamSmithaboardtheWilliams;
Fogg, 1992; Figure 1.1). A number of the whaling and sealing trips combined economic
pursuitswithscienceanddiscoveryanditisamongsttherecordsoftheseexpeditionstothe
AntarcticPeninsulathatthefirstreportsoffossilplantmaterialcanbefound.
In1819,TsarAlexanderIdespatchedtwoRussianexpeditions,onetotheArcticandthe
second to the Antarctic. Thaddeus Bellingshausen commanded the Antarctic voyage and
furtheredtheearlierdiscoveriesofCook,withacircumnavigationoftheAntarcticin1820.
Bellingshausen discovered several islands including Alexander Island, off the Antarctic
Peninsula, and Peter I Island (Figure 1.1). More controversial is the discovery of the
Antarctic continent itself. While it is clear that Bellingshausen observed the ice shelves
attached tothecontinent,andthereforecanberegardedasthediscovererofthe Antarctic
continent, this has been contested (Jones, 1982). The voyage of Bellingshausen made
significant inroads into the discovery of Antarctica but due largely to the haste in which
thevoyagewasputtogetheranddespatchedfromStPetersburg,itwaspoorlyequippedfor
scientificdiscovery(Fogg,1992).
TheUnitedStatesExploringExpeditionwasaprivatelyfundedsealingtripthatsailedin
1829andreturnedtotheUnitedStatesin1831.ThenaturalistontheexpeditionwasJames
Eights(1833)whomadegeologicalobservationsontheSouthShetlandIslandsandreported
carbonisedwoodpreservedinconglomerates,andthuspennedthefirstscientificrecordof
fossilplantsfromtheAntarcticregions.However,theseandotherdiscoveries,suchasthe