Brandand H Uni ID: 197302
Download Pdf The PPT/PDF document "DieNeueZiemsenVerlag,Wittenberg232p.Hitc..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Brandand H. DieNeueZiemsenVerlag,Wittenberg232p.Hitchcock,E.1858.AreportontheoftheConnecticutValley,especiallyitsfossilfootmarks.W.White,Boston(reprintedbyArnoPress1974),p.Lockley,M.G.1987.Dinosaurtrackssymposiumsignalsarenaissanceinvertebrateichnology.Lockley,M.G.1989.Summaryandprospectus.Gillette,D.O.,andLockley,M.G.(eds.),TracksandTraces.Cambridge Uni versityPress,N.Y.,p.Lockley,M.G.1991.TrackingCambridgeUniversityPress,N.Y.,p.130,138,141.Lockley,M.G.,andConrad,K.1989.ThepreservationandsignificanceofdinosaurtracksitesinthewesternUSA.Gillette,D.O.,andLockley,M.G.(eds.),DinosaurTracksandTraces.UniversityPress,N.Y.,p.Lockley,M.G.,andRice,A.1990.Dideverswimouttosea?:evidencefromandotherdinosaurfootprints.Ichnos,Lull,R.S.FossilfootprintsfromtheGrandCanyonoftheColorado.AmericanJournalofMcKee,E.D.1947.Experimentsontheoftracksinfinesand.JournalofSedimentaryPetrology,McKeever,PJ.1991.TrackwaypreservationineoliansandstonesfromthePermianofScotland.Geology,Padian,KandOlsen,P.E.1984a.ThefossiltrackwayPteraichnus:notbutcrocodilian.JournalofandOlsen,PE.1984b.FootprintsoftheKomodoMonitorandthetrackwaysoffossilreptiles.Copeia,1984,p.EE.1959.Trackwaysoflivingandfossilsalamanders.UniversityofPublicationsinZoology,63:1-71.1993.ArthropodtracefossilsfromthePermianDeChelly1988.Fossilvertebratefootprints.GeologyToday,4:Sparner,E.E.1984.PaleontologyintheGrandCanyonofArizona:125andenigmasfromthelatePrecambriantothepresent.TheMosasaur,2,December,p.Bennington,J.B.,Wizevich,M.C.,andBambach,1990.Upper(Namurian)amphibiantrackwaysfromtheBluefieldFormation,WestVirginia,Ichnos,1:1l1-124.T.1990.Tracks.ChapmanandHall,N.Y.,p. Permianunderprints 221) Fig.5.Crosssectionsfromthreeinthegenerallydoesnotshowofclaysorothermaterialthatcouldprovidethetoretainsuchsteep,evenoverhanging,thesefootprintsareunderprints,thedeep,mayhavebeenpreservedbythewhilethesurfacewerepartlyinfilledbysand,asinFigure3C.ApreviouspaperandTang,1991)thattheCoconinowereunlikelytobeunderprintsbecauseofthefinedetailpreservedinthem.Datahereindicatethat,contrarytotheusualinothertypesofunderprintsinpure,finesandmaycontainmoredetailthanthetruetracks.Asubstrate,suchasamudflat,withanidealtracksproducestrueprintsthataremoreanddetailedthantheIncontrast,when ani malswalkinpure,finesand,infillingofthesandatthesurfacecandetailsinthesurfacetrackswhilethesearepreservedintheclosetothesurfacemayalsobelowerinqualitythanthosebelowthesurface.Analternateforthedatashouldbecouldbeproposedthatdistincttracksarethetruetracks,andtheuppertracksarenotasclearlybecausetheyareoverprints,formedbylayersofafterthetrackswereformed.isrefutedbythepresenceofthelargesandgrainsdowntothelowestleveloftracksinthattheanimalpusheditsfeetdowntothatlevelabovethelayeroflargegrains.ItispossiblethattracksintheCoconinoSandstoneareoverprints,butthatdoesnotseemtobeanadequateforthetrackwaysdiscussedinthispaper.alsoisdifficulttoexplainthedeeptracksinFigure5iftheyarenotsometimessplitsapartinthinsheets,butitonlybreaksoutasslabsseveralcentimetersthick.Ascanbeseeninthinsections,theremaybelayersoffine-grainedandsandbetweentwocleavageplanes,eveninathinslab(Fig.2D),complexsedimentationbymodernexposedsurfacesforeachsedimentlayer.Whattypeoftrackwaywillbebythesedimentaryprocessesthatplanes,suchasvariationsingrainsize,shape,oralignment.Thesefactorsmaybethefeaturesoftheoriginalexposedsurfacesonwhichthewalked.Thusinthissandstonetheremaynotbeanyreasontoexpectthattheoriginalexposedsurfacewithtruetracksismorelikelytobefoundthanunderprints.Wheretrackwaysweremadeonclaydrapes,suchassome(1991),itisthattheclaylayersmaycontrolcleavageoftherockandproduceabiasinfavoroftruetracks.Allen,J.R.L.1989.FossiltracksandoftheBrady,L.p.1947.tracksfromtheBrand,L.1979.ontheandtheirBrand,L.R.,andTang,1991.Fossilinthean)offorunderwaterorigin.C.W.1926.FossilfromtheCanyon.Smith..v.77,no.9,p.1-41.1927.Fossilfromthev.80,no.3,p.H.1971.buchder124p.H.1974.DieDieNeue168p. BrandandKramerbelowthetopofthislayeroflargegrains,atthedarklinemarkedbyanarrowinFigure2A.thelayeroflargegrainshadbeendepositedafterthewasformed,thelargegrainswouldnothavebeensofardownintothetracks.Figure3illustratesthesequenceofeventsbytheevidencein2A.Theanimalwalkedonthesurfaceabovetheoflargegrains,pushingthemdownatleastasfarasthelowerlevelofunderprintswhichresultedfromofthesandlaminaebelowthesurface.Asthelegswerewithdrawn,theselargegrainsremaineddeepinthetrackway.Infillingofthedepressionbysandtheclarityofthetracksclosetothesurface(theupperlevel),butdidnotaffectdeeperlayers.Theremayhavebeenonlyslightvisibleevidenceofthetrackwayonthesurfaceimmediatelyafterthetrackwaywasmade. --- 3.AninterpretationoftheinFigure2A,asitwasontheslopinguponwhichtheanimalwalked.(B)legsenterthesand,largesurfacesandgrainsdownintolayers,andthesandlaminaebelowthesurface.fromlefttoright.(C)Asthelegsarethelargegrainsfillthespacewherethelegswere,andthesurfacearepartlyfilled.Thetrackwayiscoveredbymoresand.thisslabwithotherfossiltrackwaysfromthesuggeststhatanumberoftheseothermayalsobeunderprints.Evidencefavoringthisistheclarityanddepthofthefootprintsanduniformlyroundededges(Fig. 4A C),comparedfootprintswithmorediffusemarginswehaveonfinesandinthe1979)orondesertsanddunes.ThinsectionsofnineSandstonenaturalcastsoffossiltrackwaysweretoevaluatetheusefulnessofthinunderprints.Someofthesetrackwaystobeunderprints,basedontheabovecriteria,butgrainsizedifferentiation(Fig.2B,C)isnotseenclearlyasin2A.TheevidenceforunderprintsinFigureprimarilybythelayeroflargesandgrainspresentandpusheddownward.ThetracksinFigure2BandCwereimpressedintoasand,withoutgrainsizedifferencesthatcouldindicatewhethertheywereunderprints.GrainisevidentinFigure2D,butifthesetracksareunderprints,thetrueprintlevelwouldapparentlybebelowthelayeroflargesandgrainsacrossthemiddleofthepicture,sincethereisnomixingofthelargegrainsdownintothelayer.Thinsectionsareonlyhelpfulforifthesandisinlayerswithdistincttheselayersarenotpresent,underprintscanstillberecognizedifatrack-,wayisexposedattwoormorelevelsasinFigureoftheintheCoconinoSandstoneareunderprintsthisalsosuggestsanexplanationforsomefootprintsthataresodeepthatthesandonthefrontedgeofthetrackoverhangsthefootprintimpression(Fig.5).TheCoconinoiscomposedoffinesandandFig.4.withsurfacedetailsuggestingthattheyare(D)ACoconinoSandstonetrackwaythatappearstobeatrueprint.inArizona:A,Seligman;B.Ashfork;C.HermitBasin,GrandD,GrandviewTrail,GrandCanyon,traversingaslumpfeature.Bar » 5em. Fig.2.ofthinsectionsthroughnaturalmoldsofCoconinoSandstonetrackways.TwoofthefromFigureArrowmarkstheleveloftheoftheupperlayerinFigureVertebratetrackways.AllfromSeligman,Arizona,andalltothesamescale. andKramer -=-=- •.• ] Fig.I.(A)Fossiltrackwaysshowingtrackwaysontheupperlevelandthemoredistinctunderprintsexposedonthelowerlevel.NaturalmoldofapartoftheslabinA.FromSeligman,Arizona.Thebottomofthesephotographsistowardtheupslopeonthecross-bedsurface.levelandImmdeepontheupperlevel.ThiscurrentlybeingTheothertwotrackwayshavethestrideoftetrapods.Theofthesetrackwayshasameanstridelengthof4.53ern,andlookslikebold,1984).oftheleftfeetarevisibleattherightsideofFigurelA,butfadeouttowardtheleftendofthetrackway.Thetracksthatcanbebestbetweenthetwolevelsaretherightpesprints.Theyare9mmwideandmmdeeponthelowerleveland 10- 13mmwideand1-1.5mmdeepontheupperlevel.ThelargertrackwayatthebottomofFigure1Ahasalengthof13.3em.isonlyonthelowerlevelandtheprintsaremmdeep.isnotaswelldefinedasthebutitalsoappearstobeTheunderprintsonthelevel(Fig.1A)areverydistinct,deepdepressionswithroundededges,whilethetracksontheupperlevel,whichalsoappeartobeunderprints,areandmuchlessdistinct.Theevidencesuggestingthattheupperleveloftracksisanupperlevelofunderprints,ratherthantruesurfacetracks,isseeninathinsection(Fig.2A)cutthroughtheinvertebratetrackwayabovethetopFigurelB.Largesandgrainshavebeenpusheddownthroughtheupperleveloftracksfromthedistinctlayeroflargergrainsabovethisupperlevel.thelaminae,toexposetheupperlevelvisibleinFigureIoccurred1.4mm v.4,pp.InternationalJournalPlantGildReprintsavailablefromthe1996OPA(OverseasPublishersB.Y.PublishedinTheNetherlandsbyHarwoodAcademicPrintedinMalaysiaLeonardR.BrandlandJonKramer?Sciences,LamaUniversity,LornaLinda,CAGoldenValley,MNTheonlyfossilsintheCoconinoSandstoneofArizonaareAslabofCoconinoSandstonecontainsanimals,exposedattwolevelsbya1-2mmlayerofonthelowerlevelaredeeperandmuchmoredistinctthanthesameexposedonthehigherlevel.Thetracksonthelevelwereinfilledbythefinesand,whichdoesnotcontainclaysorcouldprovidecohesiveness.Thetrackwaysonthislevelalsotobeunderprints,butformedclosertothesurface.ManyotherfossiltrackwaysintheCoconinoSandstonearesincetheycloselyresembletheThemechanicsofformationmayalsoexplaintheoriginofsomethatareverydeep,withsteepsidesevenoverhangthefrontofthetrack.KeyWords:(Permian;Leonardian)isArizona.TheonlyfossilsthathavebeenfoundinthisformationarevertebrateandThevertebratetrackwayshavebeenastracksofamphibians(Lull,1918),orreptiles(Baird,citedinSpamer,1984;Peabody,1959).authorsindicateduncertaintyoftheiridentity(Gilmore,1926,1927;McKee,1947).Hau1974,1984)theichnogenusasamphibian,and(themostcommontrackwaysintheCoconinoascaseid pelyco saurtracks.hasbeen(Lockley,1989,1990)thatalargeoffossiltracksareactuallyunderprints,producedwhentheshapeofafootprintispresseddownintobelowthesurfacethattheanimalwalkedon.Insomeunderprintsmayhaveahigherpotential for thanthetrueprintsonthesedimentsurface,underprintsarenottothereworkingthatcanoccuronthesurface(Hitchcock,1858;Lockley,1987;andRice,1990).Underprintsmayalsohaveabetterforpreservationthantrueprintsifsurfacesedimentisnotpreservationoftracks(Lockley,Inthesesituationsunderprintsmaybetheonlytracespreserved.Similarly,arepreservedbelowtruetracks,thesurfacewithtruetracksmaybeerodedawayoraftertheisexposedtoerosion.Conrad(1989)thattrackwaysmadeindesertmayhavegoodtentialiftheyareinto"moistorunderlayers."hasbeenbymanyauthors(Hitchcock,1858;Sarjeant,1988;Allen,1989;LockleyandRice,1990;SundbergetaI.1990;Thulbom,1990;Lockley,underprintsarelesswelldefinedthanthetruetracks,butthereareexceptionstothis(LockleyandConrad,1989,Fig.14.2D;Thu1born,1990).Thevaryingcharacteristicsoftruetracksandunderprintshasthepotentialtocontributetoconfusion.PadianandOlsenthattheactualfeaturesatrackwayareaffectedbytheconditionsoftheaswellasbytheanatomyofthefootandtheofthelimb.ThispaperpresentsthefirstdocumentedevidenceforunderprintsinthePermianCoconinocomparestheirwithotherTwomatchingslabs(partandcounterpart)ofCoconinoArizona,beartrackwaysofanandtwotetrapodswithwellpreservedunderprintsofbothinvertebratesandtetrapods(Fig.1).Theandonetetrapodtrackwayareexposedontwolevels,separatedbya 1-2 ofsandstone.Thetrackwaytraversingverticallythroughrowsofmultiple(trackwaywidth4.5em)asischaracteristicofarthropodtrackwaysinsandstones(Brady,1947;Sadler,1993).Individualprintsaremmdeeponthelower