Europea Palaeontologica AssociatioLink betwee fossi assemblage an sedi - PDF document

Europea Palaeontologica AssociatioLink betwee fossi assemblage an sedimentar cycle an sequenceLisboa Portugal Jul 22-25t 199ConferenceAPPLIE PALAEONTOLOG AN SEQUENCSTRATIGRAPH I CARBONAT EPICONTINENTAPLATFORMSS R FERNÁNDEZ-LÓPEDepto y UE d Paleontología Fac CC Geológica (UCM e Institut Geologí Económic (CSICUCM) 28040-Madri (Spain)Abstract: Taphonomi Europea Palaeontologica Associatio WorkshoLink betwee fossi assemblage an sedimentar cycle an sequencePALAEOENVIRONMENTA AN STRATIGRAPHI CYCLEStratigraphi cycle resul fro cyclica palaeoenvironmenta change (e.g., eustatic climati and/otectoni fluctuations) Palaeoenvironmenta an stratigraphi cycle ar o variabl duratio ( 1)Sequenc stratigraph recognize systemati pattern o relativ sea-leve variatio o differenmagnitude a represente b stratigraphi cycle o differen orde ( e al., 1988 Bau &Vail 1998 Carter 1998 I th stratigraphica recor i i possibl t distinguis stratigraphisequence an cycle o differen order du t relativ sea-leve changes Elementar stratigraphisequences parasequences set o parasequences depositiona systems system tractsdepositiona sequences transgressive/regressiv cycle an megasequence o supercycle ar term o stratigraphy comprisin roc bodie o th stratigraphica recordTh continuit o th stratigraphi cycle an thei boundarie ca b teste usin biostratigraphicalbiochronological taphonomi an palaeobiologica criteria Discontinuitie i th stratigraphicarecor ma impos truncation o th fossi rang data a wel a clusterin o firs an lasappearanc datum (FAD an LADs respectively) Biostratigraphica gap an biozon truncation(i.e., gap o th stratigraphica record ma ai i th identificatio o sequenc boundarie anallo t apprais thei relativ magnitude Registrati gap (i.e., gap o th fossi record identifieb mean o ammonite hav generall smalle geochronologica amplitud tha th contemporarstratigraphi gaps an the enabl t ascertain wit greate precision th episode o regionaemersio i th Mesozoi epicontinenta platform ( 1997Som taphonomi criteri ar usefu t identif divers type o sedimentar ground an sequencboundaries Fo example th occurrenc o verticalize remain o nekti organism ma impl versoft o soupy-grounds Azimutall reoriente skeleta remain ar commo a firm an hardgrounds Truncatio o cappin o fossil provide evidenc fo stratigraphi discontinuit odenudatio o th substratePalaeobiologica criteri ar als usefu t identif change i consistenc o successiv sedimentarground an sequenc boundaries Fo example th occurrenc o scarc bentho i laminatesediment ma impl ver soft o soupy-grounds Bioturbatio texture ar commo i soft-groundsDwellin burrows suc a Thalassinoides, are wel develope i firm-grounds Boring anencruster ar ver usefu i identifyin hard an rock-grounds Abrup juxtapositio o disparatbiofacie provide evidenc fo stratigraphi discontinuityPALAEONTOLOGICA CYCLEStratigraphi cycle represen palaeoenvironmenta fluctuation tha als influence opalaeobiologica entitie an th preservatio o thei remain an traces B analog wit th modedevelope i sequenc stratigraphy palaeontolog ca provid a mode encompassin a numbe oscale o process a represente b palaeobiologica an taphonomi cycles Palaeontologica includ palaeobiologica an taphonomi cycles Palaeobiologica cycle comprispalaeoecological Palaeobiogeographica an evolutiv cyclesTh identificatio o palaeontologica cycle enabl t tes th geneti difference betwee thfossi recor an th stratigraphica record Th stratigraphica recor an th fossi recor ardifferen i nature an the ca b studie separately Th fossi recor ma suppl relevan dat opalaeoenvironment an processe whic hav lef n trace i th stratigraphica recor 1997b Th identificatio o suc palaeontologica cycle i o utmos i interpretin th environmenta cycle o Mesozoi epicontinenta platforms whe nstratigraphi recor i preserve bu reelaborate element ar widel recordedModel o taphofacie attemp t relat preservationa feature o fossiliferou deposit tenvironmenta parameters Taphonomi attribute o fossil ar ver predictabl i stratigraphicycle becaus o th dependenc o fossi preservatio upo rate o sedimentatio anenvironmenta energ ( 1995,19981EP Workshop Lisboa Portugal Jul 22-25 199 Palaeontological Association WoLinks between fossil assemblages and sedimentary cycles and Fig. 1 - Separate orders of sea-level cycles in relation with processes and distinguished in sequence stratigraphy andin carbonate epicontinental platforms.EPA Workshop. Lisboa, Portugal, July 22-25th, -3-2-11st order2nd order3rd order3rd order4th order2nd order3rd order3rd order3rd order4th order5th order6th orderTAPHONOMIC Ocean-basin volume change�s (100 Ma)(10-100 Ma)(5-10 Ma)Eustasy / tectonics (1-5 Ma),3 -1 Ma)Glacio-eustasy (eccentricity, ca 100 Ka)(obliquity, ca 40 Ka) 20 Ka)Eustasy-sediment supply (Ka)Cycles of MilankovitchTidal cyclesAsh fall and volcanic eventsMegasequences - supercyclesSets of Megataphosequences - supertaphocyclesSets ofOriginations (Ammonites biochrons)Ecophenotypic Europea Palaeontologica Associatio WorkshoLink betwee fossi assemblage an sedimentar cycle an sequencesA a resul o cyclica environmenta fluctuations th successiv recorde association o aparticula regio o sedimentar basi ca sho cyclica variation i thei preservationa featuresCondition whic ar conductiv t stabilize transfor o replicat th biogeni remain o th tracfossil ca occu cyclically I particular som variation o th preservationa feature an thdistributio o th recorde association i th carbonat epicontinenta platform enabl tdistinguis taphonomi cycle resultin fro relativ sea-leve changes A taphonomic cyclecomprise tw o mor successiv recorded-association showin cyclica variation i theipreservationa features a a resul o a palaeoenvironmenta cycl ( 1997a1997b Elementar taphonomi sequences taphosequences set o taphosequencesdeepening/shallowin taphorecords deepening/shallowin taphocycles megataphosequence ansupertaphocycle ar geneti term o taphonom comprisin preserve elements taphonipopulation o preserve association o th fossi recordCertai pattern o palaeobiologica ar correlate wit palaeoenvironmentafluctuation throug th developmen o stratigraphi cycles A a resul o palaeoenvironmentacycles th successiv palaeobiologica entitie o a particula regio o sedimentar basi ca shocyclica variation i thei ecological biogeographica and/o evolutionar features Apalaeobiological cycle comprise tw o mor successiv palaeobiologica entitie (i.e., organismspopulation o communitites showin cyclica variation i thei ecological biogeographica o features a a resul o a palaeoenvironmenta cycle Palaeobiologica cycle ar term comprisin organisms biologica population an communitie o th past Somvariation o th palaeobiologica entitie i th carbonat epicontinenta platform enabl tdistinguis palaeobiologica cycle resultin fro relativ sea-leve changesPalaeoecologica response t environmenta fluctuation includ ecophenotypi cyclesspecie substitutions ecologica succession an communit replacements A gradationa serie ovarian form withi a taxonomi grou ca b produce b nongeneti modificatio o thphenotyp a a resul o environmenta change throug a sedimentar cycle Iterativecophenotypi change o thi typ constitut successiv palaeoecologica cyclesSpecie substitution i respons t changin environmenta parameter ma involvchange i taxonomi composition o association an relativ abundanc o (ichno-)speciesLong-ter (10' t 100' o Ka communit replacemen an latera shiftin o taxonomigradien (o community-leve trackin an latera shiftin o trackin biota i 1998 noecologica succession commonl involve a predictable facies-relate recurrenc o speciesMigratio o facie belt i response t sea-leve fluctuation ma yiel a predictabl patter ocommunit replacemen throug stratigraphi cyclesPattern o biodispersa ma b relate t fluctuation o se level Majo rise i se levema connec formall isolate biogeographi area permittin th rapi sprea o plankti marinlarva acros severa sedimentar basin Th appearanc o exoti specie withi a particulasedimentar basi ca b relate t relativ se leve rises Episodi immigratio event i carbonatepicontinenta platforms i relatio t se leve rises ar typica o nekti form suc a ammonoidan benthi form wit plankti larvaeEvolutionar response t palaeoenvironmenta fluctuation includ originations extinctionspecie evolutio an adaptiv radiation ( 1992 Sagema e al., 1997 I epicontinentaplatforms originatio an extinction cronocline an ecotype ar commonl relate t factor suca relativ sea-level climate oxygenatio an sediment-suppl fluctuation tha produc cycles Evolutionar bioevent commonl ar associate wit boundarie oparasequence an stratigraphi cycle o thir orde i shallo epicontinenta platformsFloodin an deepenin o epicontinenta area increas habitabl ecospac an favooriginatio o shallow-marin form an adaptiv radiation o stenotopi taxa I epicontinentaplatforms extinction ma b associate wit habitat-are reductio durin se leve falls o witanoxi event durin se leve rises Extinction events accelerat i sit evolution an migratioma resul fro th bottom-wate anoxi durin pea transgression i shallo epicontinentaplatform ( 1994Phyleti evolution chronocline o gradationa serie o evolutiv change i th successivmember o a taxonomi group fro primitiv form toward derivat forms ma b a respons tenvironmenta change generatin stratigraphi cycles Som cas studie hav documente long1EP Workshop Lisboa Portugal Jul 22-25 199 Europea Palaeontologica Associatio WorkshoLink betwee fossi assemblage an sedimentar cycle an sequenceter anageneti change tha appea t relat t parasequence an transgressive/regressivcyclesEvolutionar change i respons t changin environmenta parameter ma involv thdevelopemen o ne ecotype withi a taxonomi group Evolutio o stenohalin specie durinshallowin phase involve r-selection favourin paedomorphs whil k-selectio operate durin phase givin ris t peramorphi form (cf 1987CONCLUSIONTaphonomi an palaeobiologica dat enabl th interpretatio o relativ change o selevel cyclica an o differen o magnitude occurre i carbonat epicontinenta platformsThes palaeontologica dat ar o stratigraphi interes sinc the provid a independen tes oth cycle distinguishe i sequenc stratigraphy Palaeontologica knowledg provid dat tidentifyin stratigraphi cycle an discontinuities Conversely th stratigraphi knowledg provid apredictiv framewor withi whic t tes palaeontologica cycle an discontinuities* Thi wor i a contribution t th projec PB96-083 (DGESIC-CSIC)REFERENCEBAUM, G.R. & VAIL, P.R. (1998) - A ne foundatio fo stratigraphy Geotimes, Alexandria Novemberpp 31-35BRETT, C.E. (1995) Sequenc stratigraphy biostratigraphy an taphonom i shallo marinenvironments Palaios, Tulsa 10 pp 597-616BRETT, C.E. (1998) - Sequenc stratigraphy Paleoecology an evolution bioti clue an response tsea-leve fluctuations Palaios, Tulsa 13 pp 241-262CARTER, R.M. (1998) Tw models globa sea-leve chang an sequenc stratigraphi architectureSedimentary Geology, Amsterdam 122 pp 23-36FERNÁNDEZ-LÓPEZ, S. (1997a) - Ammonites Clino tafonómico y ambiente sedimentarios RevistaEspañola d Paleontología, Madrid 12 pp 102-128FERNÁNDEZ-LÓPEZ, S. (1997b) - Ammonites taphonomi cycle an stratigraphi cycle i carbonatepicontinenta platforms Cuadernos d Geología Ibérica, Madrid 23 pp 95-136HALLAM, A. (1987) Radiation an extinction i relatio t environmenta chang i th marin LoweJurassi o northwes Europe Paleobiology, Chicago 13 pp 152-168HALLAM A (1992 - Phanerozoi sea-leve changes Columbia University Press, Ne York 26 ppSAGEMAN, - Cenomanian/Turonia bioeventan ecostratigraph i th Wester Interio basin contrastin scale o local regional an globaevents I C.E Bret & G.C Bair (eds.) Paleontologica events Stratigraphic ecologica anevolutionar implications Columbia University Press, Ne York pp 520-570SCHENCK, H.G. (1940) - Applie paleontology Bulletin o the American Association o PetroleumGeologist, Tulsa 24 pp 1752-1778WIGNALL, P. W. (1994) - Blac shales Oxford Monographs o Geology and Geophysics, Oxford 30127pWILGUS, C.K.; HASTINGS, B.S.; KENDALL, C.G.ST.C; POSAMENTIER, H.W.; Ross, C.A. & VAN WAGONER, J.C.(eds. (1988 - Sea-leve change - a integrate approach SEPM Special Publication, Tulsa 42pp 1-4071EP Workshop Lisboa Portugal Jul 22-25 199