, 25). Despite lacking an erosive base, Bonebeds 2 and 4 exhibit loosely packed bioclasts/clasts, and Ophiomorpha burrows that extend up to 2 meters below the β-interval that are infilled with densely packed bonebed debris. These bonebeds also exhibit clear trace fossils within the bonebed. These data indicate that certain bonebeds have been bioturbated and biologically mixed, directly modifying their internal architecture; such biologically mixed concentrations are difficult to interpret (e.g., [73]). The presence of coarse bonebed debris infilling burrows below bonebeds indicates bioturbating invertebrates were able to transpose clasts and bioclasts up to 5 cm in length, and up to 2–3 meters below bonebeds (e.g., Fig. 26). This indicates that the architecture of a bioclastic accumulation (when bioturbated) may be misleading when applying the bioclastic concentration model of Kidwell [1]. Bonebeds 2 and 4 both contain a large amount of phosphatic nodules and phosphatized bioclasts, indicating that seafloor erosion was a factor in its formation, although the lack of a clearly preserved scour means its architecture would be interpreted as a hiatal concentration in Kidwell’s [1] scheme (Fig. 25). This has implications for the interpretation of other marine vertebrate bonebeds; for example, Pyenson et al. [105] interpreted the middle Miocene Sharktooth Hill Bonebed as a hiatal concentration rather than a lag concentration due to the lack of evidence of erosion. However, it is possible that an erosional scour was present at some stage, and subsequently erased by bioturbators (Fig. 27); this possibility is borne out by the abundance of fragmented and otherwise taphonomically damaged skeletal elements reported from the Sharktooth Hill Bonebed [105]. These new observations from the Purisima Formation indicate that bonebed architecture – just like primary sedimentary structures – can be biologically modified after deposition, with the potential to drastically affect interpretations of bonebed genesis. Furthermore, this style of information loss means that it may not be possible to determine a mode of formation from bonebed architecture (such as in [1], and [105]) in the case of bioturbated bonebeds. PPT PowerPoint slide

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, 25). Despite lacking an erosive base, Bonebeds 2 and 4 exhibit broadly compact bioclasts / clasts, and Ophiomorpha burrows that cover up to 2 meter below the β - interval that are infilled with densely pack bonebed debris. These bonebeds besides exhibit clear trace fossils within the bonebed. These data argue that certain bonebeds have been bioturbated and biologically mixed, immediately modifying their internal architecture; such biologically mixed concentrations are difficult to interpret (for example, [ 73 ]). The presence of coarse bonebed debris infilling burrows below bonebeds indicates bioturbating invertebrate were able to transpose clasts and bioclasts up to 5 cm in length, and up to 2–3 meters below bonebeds (for example, Fig. 26). This indicates that the computer architecture of a bioclastic accumulation (when bioturbated) may be misleading when applying the bioclastic concentration mannequin of Kidwell [ 1 ]. Bonebeds 2 and 4 both contain a large amount of phosphatic nodules and phosphatized bioclasts, indicating that seafloor corrosion was a component in its formation, although the lack of a clearly preserved scour means its architecture would be interpreted as a hiatal concentration in Kidwell ’s [ 1 ] scheme (Fig. 25). This has deduction for the interpretation of other nautical vertebrate bonebeds; for case, Pyenson et al. [ 105 ] interpret the middle Miocene Sharktooth Hill Bonebed as a hiatal concentration rather than a lag concentration due to the lack of evidence of erosion. However, it is possible that an erosional scour was present at some stage, and subsequently erase by bioturbators (Fig. 27); this possibility is borne out by the abundance of fragmented and otherwise taphonomically damaged skeletal element reported from the Sharktooth Hill Bonebed [ 105 ]. These new observations from the Purisima Formation indicate that bonebed computer architecture – just like chief sedimentary structures – can be biologically modified after deposition, with the potential to drastically involve interpretations of bonebed genesis. Furthermore, this style of information personnel casualty means that it may not be possible to determine a mode of geological formation from bonebed architecture (such as in [ 1 ], and [ 105 ]) in the sheath of bioturbated bonebeds. PPT PowerPoint slide 

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, 25). Dfspite lacking an erosivt base, Bonebeds 2 cbd 4 exiibit lkosely pxcked bioclasts/clasts, and Opiiomirpha burrows that extend uo to 2 metvrs below the β-unterval tizt are lufillsf wich densely packec bonebed gebris. These bmndbzds also exhibit clear trace fossils within tje bonebed. Thefe dsea ihdicate that certain bonebeds have been bpoturbated and biplogically mixed, directly lodivying their internwl architecjhre; wuch biologizally mixed concentratjons are difficult to interpret (e.g., [73]). Che presencg kf woarse boneued defris infillikb burrmws belpw bonebeds incicetes bioturbating inverteurates were able to jranspose wlcsts and bioclasts up ti 5 cm in nenggy, avd hp tk 2–3 metfrs below bonsbeds (e.g., Fit. 26). This indicates tnae the architecfure os w bioclastic accumulation (when bioturbaued) mzy be misleading when applying the bioclastif concentwation model of Kidwell [1]. Bonebeds 2 and 4 both contdin a uaryc xnoknt of phosphatic nodules and phosphatized bijdlssns, indicating thab seafloor erosion wws w factor in ijs formcfikn, although the lafk of a cleaely presewved scour means its architectuee would be pnteepreted as a hiatap concentracion im Kideell’s [1] scheme (Fig. 25). This has implicatiojs for ths interpretation uf ptver marine vertebrate bonefeds; for xxampke, Pyenron gt al. [105] ynterpretef the middle Miocene Shagktoojh Hiln Bonebed ws a hiatal concentration rathec than a lag votcettration due bo the lack of qvidence of erpsion. Hjwevef, it is poasible vhat an erosyonal scour wdd present at some stwge, qnd wubsequdvtly erased by bioturbanoxs (Fig. 27); tyis possibility is botns out by the abbudqnce of fragmenyed anq ltierwifa taphonomicdlly daosged rkeletal elcmevts teported from the Shdrktkoth Hill Bonebed [105]. Tmese new ibservatyons from the Purisima Formatioj indmcate vhat bpnefed architecture – just like prjmary sedlmektary structuwes – can be biolpgically modified after deposition, with the potential to erastically affect nnuerpretations of bjnebed getesis. Furthermore, thus style of inforkation loss means thaf it mdy noh be possible to determine a mode of formation from bonebed architecture (wuch as in [1], and [105]) ih thr casv oy bnoturbaeed uoiebeds. PPT PowerPpint slide

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, 25). Despite lacking an erosive base, and exhibit loosely bioclasts/clasts, and Ophiomorpha 2 below the β-interval are infilled with packed bonebed debris. These bonebeds also clear trace fossils within the bonebed. These data indicate that certain bonebeds have bioturbated and biologically mixed, directly modifying their internal architecture; such biologically mixed concentrations difficult interpret [73]). presence of coarse bonebed debris infilling burrows below bonebeds indicates bioturbating invertebrates were able to transpose and bioclasts up to 5 cm in length, up to 2–3 meters bonebeds (e.g., Fig. 26). This that architecture of bioclastic (when may be misleading applying the bioclastic concentration model of Kidwell [1]. Bonebeds 2 and 4 both contain a large amount phosphatic nodules bioclasts, indicating seafloor was factor in its the lack of a clearly preserved architecture would be interpreted as a hiatal concentration Kidwell’s [1] (Fig. 25). This has implications for interpretation of other marine vertebrate bonebeds; for example, et al. [105] interpreted the middle Miocene Sharktooth Hill Bonebed as a hiatal concentration rather lag concentration due to lack of evidence erosion. it possible an erosional was present at some stage, and subsequently erased by bioturbators (Fig. this possibility is borne out by the abundance of fragmented taphonomically skeletal elements reported the Sharktooth Hill Bonebed These observations from the Purisima that architecture primary structures can be biologically modified deposition, with the potential to affect interpretations of bonebed information loss means that it may not be to determine a mode of formation from architecture (such as in [1], and [105]) in the case of bioturbated PPT PowerPoint slide PNG larger image larger image TIFF original Download: Figure 27. The
, 25). Despite lacking an erosive baSe, Bonebeds 2 And 4 exHibIt lOoSely PackEd bioclasts/claSTs, anD Ophiomorpha burrows thaT exteNd UP to 2 mETeRs belOw the β-iNTeRVAl tHaT aRe iNfILlEd witH deNsely paCked bonebeD deBrIs. These bonebEDs Also exhibiT clEar trace fossIls Within ThE boNEbed. THesE data IndicaTE that cErtain bonEbEDs have BEen biotURBaTed aNd biologically mixED, dIRectly modifyinG their InTErNAL arChiTecture; sucH bIologICally miXEd CONCenTRations are difFicult to intERprEt (e.g., [73]). ThE pResENce of cOarse BoNEbeD debris infiLlinG burrows bElow boNEbeds inDIcates bIoturbAtiNg iNverTEbRaTes WeRE abLE tO trANspOse clastS aNd BioclAsts UP TO 5 Cm in LenGth, aNd up tO 2–3 meters below bOneBeds (E.G., FiG. 26). This IndicAtes ThAt the ArchitEcturE oF a bioclastic accUmulAtion (when BioTuRbaTeD) may bE MisleaDinG whEn applyIng the bIOclAsTIC CoNcentration model of kiDWElL [1]. BonebedS 2 and 4 boTH cOnTAin a largE aMouNt of PHOsphaTic nODuLes and phOsphatIZeD bIoclastS, iNdicatInG thAt sEafloOR eroSion waS a factor In its FOrmation, althouGH the lack of a clEArLY PrEServEd sCour means itS arcHItecTure WOuLd bE InterPreteD aS A hIAtal concentration in kiDwell’s [1] SchemE (Fig. 25). This has imPlications FOR The interPretATiON of other marine VerteBrate bonebEDs; for exaMple, PYenson et Al. [105] interprETEd the midDle mioCenE ShARKtOoth Hill BonebED As a hIaTal concEntRation rAthEr tHan A laG cOncentratIon due to ThE lAcK oF evIdencE Of erosioN. HOweVeR, it Is posSIble thAt an eRosiOnAl SCouR was preSEnT AT somE sTaGe, anD suBsEquenTly eRAseD by biotUrbators (FIg. 27); tHIs poSsIbIlity is Borne out by the AbUndance of fRaGmeNted anD OTherwise Taphonomically damaged skELetal elEmeNts rePortEd from the shaRktootH HiLL BonebEd [105]. ThesE new oBsErvATIons fROM tHe PUrIsima FormaTIOn iNdicaTe That Bonebed Architecture – just liKE prImary sedimentAry StruCTUrEs – cAN bE BioLoGIcaLLY modified after dEposition, wItH ThE potential TO drAsTically Affect iNterpREtationS of bonebeD genesis. FUrTherMORe, tHis style of InformatIon loss meANs thaT It May noT be PossibLe To dEtermIne a moDE of FormaTion frOm BonebeD archItEcture (suCh as in [1], and [105]) in the case of bioTurbatEd bonEbeDs. PPT PoweRPoINt sLide

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, 25). Despite lacking anerosive ba se, B one bed s2 an d 4exhibit loosel y  pac ked bioclasts/clasts,and O ph i omor p ha  burr ows tha t  e x t end  u pto2m et ers b elo w the β -intervaltha tare infilled wi th densely  pa cked bonebed  de bris.Th ese boneb eds  also  exhib i t clea r trace f os s ils wi t hin the b on ebed . These data indi c at e  that certainbonebe ds ha v e  be enbioturbate dand b i ologica l ly m i xed ,  directly mod ifying thei r  in ternal  a rch i tectur e; su ch bio logically m ixed  concentr ations are dif f icult t o inte rpr et(e.g . ,[7 3]) .T hep re sen c e o f coarse  b on ebeddebr i s i nfil lin g bu rrows  below bonebe dsindi c ate s bio turba ting  i nvert ebrate s wer eable to transpo se c lasts and  bi oc las ts  up t o  5 cminlen gth, an d up to 2–3  m e t e rs  below bonebeds (e .g . ,  F ig. 26).  Thisi nd ic a tes that  t hearch i t ectur e of abioclast ic acc u mu la tion (w he n biot ur bat ed)  mayb e mi sleadi ng whenapply i ng the bioclas t ic concentrat i on m od e l of  Ki dwell [1].Bone b eds2 an d  4  bo t h con tainal ar g e amount of phospha ti c nodu les a nd phosphatiz ed bioclas t s ,  indicat ingt ha t  seafloor eros ion w as a facto r  in itsforma tion, al though th e lack ofa c lea rly  pr e s er ved scour mea n s  its  a rchitec tur e would  be  in ter pre te d as a hi atal con ce nt ra ti onin Ki d well’s [ 1]  sc he me(Fig. 25). T his h as i mp li c ati ons for th e inte rp re tati onof  othe r ma r ine  verteb rate bone bed s ; fo rex ample,Pyenson et al .[105] inte rp ret ed the m iddle Mi ocene Sharktooth Hill B o nebed a s a  hiat al c oncentrat ion  rathe r t h an a l ag con centr at ion d ue to t he  la ck  of eviden c e  of  eros io n. H owever,  it is possible th a t a n erosional s cou r wa s pr ese n ta t s om e  st a g e, and subseque ntly erase db ybioturbato r s ( Fi g. 27);  this p ossib i lity is  borne ou t by theab unda n c e o f fragment ed and o therwiset aphon o mi cally  da magedsk ele tal e lement s  re porte d from  t he Sha rktoo th  Hill Bo nebed [105]. These newobserv ation s f rom the P uri s ima  Formatio n in dicate tha t b one bed a rch i tectu re – ju stl ike p rima r y sedimen t ar y s t r uc tures – can b e  bi ologi cal l y modi fied  after deposition ,  with the pote ntia l todra s tica ll y affect inter pre ta t i ons of b on ebed genesi s. Furth er m ore,this s tyle o f infor m a ti o n loss  mea nsthat it m ayno t  be pos si bl e  to de term in e a mo de off orma t i on from bonebedarchi t e cture (su ch as  i n [1],a nd [ 105]) in t he case ofbiotur bate d bon ebeds.PP T Powe rPo in t slide

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, 25)._Despite lacking_an erosive base, Bonebeds_2 and_4_exhibit loosely_packed_bioclasts/clasts, and Ophiomorpha_burrows that extend_up to 2 meters_below the β-interval_that_are infilled with densely packed bonebed debris. These bonebeds also exhibit clear trace fossils_within_the bonebed._These_data_indicate that certain bonebeds have_been bioturbated and biologically mixed,_directly modifying_their internal architecture; such biologically mixed concentrations are_difficult_to interpret (e.g.,_[73]). The presence of coarse bonebed debris infilling burrows_below bonebeds indicates bioturbating invertebrates were_able to transpose_clasts_and_bioclasts up to 5_cm in length, and up to_2–3 meters below bonebeds (e.g., Fig._26). This indicates that the architecture of_a bioclastic accumulation (when bioturbated) may_be misleading when applying the_bioclastic concentration_model of Kidwell [1]. Bonebeds_2 and 4_both contain_a large amount_of phosphatic nodules and phosphatized bioclasts,_indicating that seafloor_erosion was a factor in its_formation,_although the lack_of_a_clearly preserved_scour means its_architecture_would be_interpreted_as a hiatal concentration in Kidwell’s_[1]_scheme (Fig. 25). This has implications for_the interpretation of other_marine_vertebrate bonebeds; for example,_Pyenson et al. [105] interpreted_the middle Miocene Sharktooth Hill Bonebed_as a_hiatal concentration_rather than a lag concentration due to the lack of evidence_of erosion. However, it is possible_that an erosional scour_was present_at_some stage, and_subsequently_erased by_bioturbators (Fig. 27); this possibility is borne_out by_the abundance of fragmented and otherwise_taphonomically damaged skeletal elements_reported_from the Sharktooth Hill Bonebed [105]._These new observations from the Purisima_Formation indicate that bonebed architecture_–_just_like primary sedimentary structures –_can be biologically modified after deposition,_with the potential_to drastically affect interpretations of bonebed genesis._Furthermore,_this style of information loss means_that_it may not be possible to_determine_a_mode of formation from bonebed_architecture (such as in [1], and_[105]) in the case of bioturbated bonebeds. PPT PowerPoint_slide

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