This work presents the results of a palaeontological analysis focused on twenty-six species sampled in five sections of the Tamengo and Guaicurus formations, Corumbá and Ladário regions: Corcal and Laginha quarries, Porto Sobramil, Porto Figueiras and Ecoparque Cacimba. Besides, palaeoecological and palaeoenvironmental inferences are presented based on the occurrence of this fossil assemblage. Cloudina carinata Cortijo et al., 2010, previously documented in Spain and Siberia, presents an unprecedented occurrence in the American continent, in siltstones of the Tamengo Formation at Porto Figueiras section, Municipality of Corumbá, Mato Grosso do Sul State, Brazil. The biota of the Tamengo Formation is updated and composed of three biomineralizing metazoans, including poriferan spicules, putative sponge gemmule, and a sessile epibiontic prokaryotic colony. The present work also deals with the taxonomy and stratigraphic distribution of four ichnospecies and three vendotaenid species that integrate the updated benthic fauna for the upper portion of Corumbá Group. The species diversity of the Tamengo Formation was complemented by the occurrence of sixteen microfossil species that possibly represent a marine planktic assemblage. A dramatic change was identified in the palaeoenvironmental conditions of the Tamengo to Guaicurus formations, followed by a mass extinction event, possibly linked to the global Ediacaran-Cambrian mass extinction. In addition, organic-walled microfossils were prepared and analyzed from sections of three countries: nine species from the Nomtsas Formation, Namibia; four species from the Tagatiya Guazu Formation, Paraguay; and six species from the Dengying Formation, China. An international biostratigraphic essay consisting of six biozones is proposed for the uppermost Ediacaran and one biozone for the earliest Cambrian.
RESUMEN
Se presenta en este trabajo el análisis paleontológico de 26 especies fósiles muestradas en cinco cortes de las Formaciones de Tamengo y Guaicurus en las regines de Corumbá y Ladário: canteras de Corcal y Laginha, Porto Sobramil, Porto Figueiras y Ecoparque Cacimba. Además, se añaden varias interpretaciones paleoecológicas y ambientales, basadas en el registro fósil. Cloudina carinata Cortijo et al., 2010, previamente citada en España y Siberia, aparece por primera vez en el continente Americano, concretamente en limolitas de la Formación Tamengo en el corte de Porto Figueiras, Corumbá, Estado de Mato Grosso do Sul, Brasil. La biota de la Formación Tamengo incluye tres metazoos mineralizados, que incluyen espículas de poríferos, posibles gémulas de esponjas y una colonia sésil de procaiotas epibentónicos. Este trabajo se centra en la taxonomía y distribución estratigráfica de cuatro icnoespecies y tres especies de vendoténidos que forman la fauna bentónica de la parte superior del Grupo de Corumbá. La biodiversidad de la Formación Tamengo ha sido completada con el registro de 16 especies microfósiles que representan posiblemente una asociación plantónica marina. Se ha identificado un cambio drástico en las condiciones ambientales de las Formaciones Tamengo y Guaicurus, que culminan en un evento de extincinón masiva posiblemente relacionado con la extincición en masa que marca el tránsito global Ediácarico-Cámbrico. Por otro lado, se han extraído microfósiles de pared orgánica de varios afloramientos: nueve especies de la Formación de Nomtsas (Namibia), cuatro de la Formación Tagatiya Guazu (Paraguay) y seis de la Formación Dengying (China). Se propone un marco bioestratigráfico para el Ediacárico terminal que incluye seis biozonas y una biozona para el Cámbrico basal.
KeywordsEdiacaran-CambrianCorumbá GroupBiostratigraphyMicropaleontologyPalabras claveEdiacárico-CámbricoGrupo de CorumbáBioestratigrafíaMicropaleontologíaIntroduction
The aim of this work is to present an analysis on the taxonomy and stratigraphic distribution of some selected species of the Tamengo and Guaicurus formations, Ediacaran-Cambrian boundary interval in Brazil, in order to propose a chronobiostratigraphic framework for the Ediacaran-Cambrian transition. In addition, palaeoecological and palaeoenvironmental inferences are presented as well as a lithostratigraphic update of the sections in Corumbá and Ladário regions, Mato Grosso do Sul State, Brazil. Considering the scarcity of micropalaeontological data from uppermost Ediacaran sections, samples from three additional localities were prepared and analyzed from the Nomtsas Formation (Namibia), the Tagatiya Guazu Formation (Paraguay) and the Dengying Formation (China). Finally, another objective of this work is to compare the results obtained from the palaeontological analysis of the Tamengo Formation with those already published from uppermost Ediacaran sections, especially in Paraguay, Uruguay, Argentina, Namibia, China, Russia, Canada, United States and Oman.
Results
Twenty-six species integrate the study fossil assemblage of the Tamengo and Guaicurus formations. They were clustered into six categories: biomineralizing metazoans, biomineralizing microfossils, vendotaenids, ichnofossils, organic-permineralized microfossils and organic-walled microfossils.
The studied fossil assemblage of the Tamengo Formation consists of twenty-three species, four of which represent benthic and sessile, biomineralizing epibionts: Cloudina lucianoi (Beurlen & Sommer, 1957), C. carinata Cortijo et al., 2010, Corumbella werneri Hahn et al., 1982 and indeterminate sponge remains. Three ichnospecies represent activity of vagile organisms of benthic habit: Multina minima Uchman, 2001, Gordia marina Emmons, 1844 and Pilichnus cf. P. dichotomus Uchman, 1999. Multina minima points to an endobiot organism, while Gordia marina and Pilichnus cf. P. dichotomus represent epibiont vagile explorers on the water-sediment interface. Additionally, sixteen species probably derived from planktic organism, fifteen of which are small organic-walled sphaeromorph microfossils that possibly represent the marine plankton: Arctacellularia januarensis Denezine, 2018nomem nudum, Leiosphaeridia ternata (Timofeev, 1966), L. crassa (Naumova, 1949), L. jacutica (Timofeev, 1966), L. minutissima (Naumova, 1949), L. tenuissima Eisenack, 1958, L. obsuleta (Naumova, 1949), Bavlinella faveolata Vidal, 1976, Bambuites erichsenii Sommer, 1971, Synsphaeridium sp., Jacutianema sp., Lophosphaeridium sp., Ostiama microcystis Hermann (in Timofeev et al., 1976), Navifusa sp., gen. et sp. 1 and one species of permineralized microfossils, Chuaria circularis Walcott, 1899. The sessile epibiont prokaryotic-colony Vendotaenia antiqua was previously reported from the Cerradinho and Bocaina formations (Zaine, 1991), and herein the occurrence is confirmed from the Tamengo Formation.
Four species represent the benthic fossil assemblage for Guaicurus Formation: Eoholynia corumbensis Gaucher et al., 2005, Tawuia dalensis Hofmann (in Hofmann & Aitken, 1979), Multina minima and Didymaulichnus lyelli (Rouault, 1850). From the total, three species have occurrences restricted to this formation: Eoholynia corumbensis, Tawuia dalensis Hofmann (in Hofmann & Aitken, 1979) and Didymaulichnus lyelli; only Multina minima also occurs in the Tamengo Formation. It is noticeable that the Tamengo Formation exhibits the greatest biodiversity.
The integration of the information regarding the taxonomy and stratigraphic distribution of the above-reported species was presented as a biostratigraphic essay composed of seven biozones, respectively named, from base to top: Cloudina Assemblage Superzone that is distributed in all 15 analyzed sections. There are three biozones inserted in this superzone distributed in sections of Brazil and Paraguay: Cloudina lucianoi/Corumbella werneri Interval Zone; Corumbella werneri Range Zone; and Corumbellla werneri/Cloudina lucianoi Interval Zone (Adôrno et al., 2016, 2017). It was possible to propose two subzones: Bavlinella faveolata - Leiosphaeridia minutissima Assemblage Subzone inserted in the basal part of Corumbella werneri Range Zone and Vendotaenia antiqua-Cloudina lucianoi Concurrent-Range Subzone at the upper portion of the Corumbella werneri/Cloudina lucianoi Interval Zone. The first subzone spans across Brazil, Argentina, Uruguay, Namibia and China; the second across Brazil, Namibia, China and Siberia. Finally, Eoholynia corumbensis Range Zone was proposed for the base of the Guaicurus Formation at Laginha quarry, lowermost Cambrian. The geographic distribution of this biozone is restricted to Laginha quarry locality so far (Fig. 1).
Biostratigraphic proposal based on the stratigraphic distribution of the species from the Tamengo Formation; palaeontological informations from the selected sections out of Brazil (Zang & Walter, 1992; Hagadorn & Waggoner, 2000; Hofmann & Mountjoy, 2001; Amthor et al., 2003; Gaucher et al., 2005; Kontorovich et al., 2009; Warren et al., 2011, 2012, 2013, 2017, 2019; Smith et al., 2017; Adôrno 2019); data from Corcal quarry after Parry et al. (2017).
Conclusions
Twenty-six species were studied from the Tamengo and Guaicurus formations, twenty-three of which represent benthic biomineralizing epibionts of sessile habit: Cloudina lucianoi, C. carinata, Corumbella werneri and an indeterminate species of porifera. Vendotaenia antiqua represents a sessile epibiont prokaryotic-colony. Three ichnospecies represent activity of vagile organisms: Multina minima, Gordia marina and Pilichnus cf. P. dichotomus. Multina minima represents endobiot organisms while Gordia marina and Pilichnus cf. P. dichotomus represent epibiont vagile explorers on the water-sediment interface. Additionally, sixteen species probably derived from planktic organisms, such as Arctacellularia januarensis nomem nudum, Leiosphaeridia ternata, L. crassa, L. jacutica, L. minutissima, L. tenuissima, L. obsuleta, Bavlinella faveolata, Bambuites erichsenii , Synsphaeridium sp., Jacutianema sp., Lophosphaeridium sp., Ostiama microcystis, Navifusa sp., gen. 1 sp. 1 and one species of organic-permineralized microfossils, Chuaria circularis.
Four species represent a benthic fossil assemblage for the Guaicurus Formation: Eoholynia corumbensis, Tawuia dalensis, Multina minima and Didymaulichnus lyelli. From the total, three species have occurrences restricted to this formation, and only Multina minima shows occurrences in the Tamengo Formation.
Seven biozones were proposed, from bottom to top: Cloudina Assemblage Superzone that is distributed in all 15 analyzed sections in Brazil, Paraguay, Uruguay, Argentina, United States, Canada, Namibia, Oman, Russia and China. Inserted in this superzone, there are three biozones, distributed in sections of Brazil and Paraguay: Cloudina lucianoi/Corumbella werneri Interval Zone; Corumbella werneri Range Zone; Corumbellla werneri/Cloudina lucianoi Interval Zone. It was possible to propose two subzones: Bavlinella faveolata - Leiosphaeridia minutissima Assemblage Subzone inserted in the base of Corumbella werneri Range Zone and Vendotaenia antiqua-Cloudina lucianoi Concurrent-Range Subzone at the upper portion of the Corumbella werneri/Cloudina lucianoi Interval Zone. The first subzone spam across Brazil, Argentina, Uruguay, Namibia and China, the second across Brazil, Namibia, China and Siberia. Finally, Eoholynia corumbensis Range Zone was proposed at the base of Guaicurus Formation at Laginha quarry, lowermost Cambrian. The geographic distribution of this biozone is restricted to Laginha quarry locality so far.
ReferencesAdôrnoR.R.2019PhDUniversity of BrasíliaAdôrnoR.R.Do CarmoD.A.WaldeD.H.G.DenezineM.BoggianiP.C.Sousa e SilvaS.C.VasconcelosJ.R.TobiasT.C.GuimarãesE.M.VieiraL.C.FigueiredoM.L.CF.MoraesR.CaminhaS.A.SuarezP.A.Z.PinhoD.RodriguezC.G.V.201635th International Geological CongressCapetownSession: The Dawn of Animals, Abstracts, 41-44AdôrnoR.R.Do CarmoD.A.WaldeD.H.DenezineM.BoggianiP.C.SousaS.C.VasconcelosJ.R.TobiasT.C.GuimarãesE.M.VieiraL.C.FiguereidoM.F.CaminhaS.A.SuarezP.A.Z.RodriguezC.G.V.PinhoD.M.SchneiderG.MuyambaR.2017Cloudina lucianoi (Beurlen & Sommer, 1957), Tamengo Formation, Ediacaran, Brazil: taxonomy, analysis of stratigraphic distribution and biostratigraphy3011935https://doi.org/10.1016/j.precamres.2017.08.023BeurlenK.SommerF.W.Observações estratigráficas e paleontológicas sobre o calcário Corumbá. Rio de Janeiro. Departamento Nacional de Produção Mineral, Divisão de Geologia e Mineralogia1957168135CortijoI.Martí MusM.JensenS.PalaciosT.A new species of Cloudina from the terminal Ediacaran of Spain2010176110https://doi.org/10.1016/j.precamres.2009.10.010DenezineM.2018Dissertação de mestradoUniversidade de BrasíliaBrasília, DFEisenackA.Mikrofossilien aus dem Ordovizium des Baltikums. 1. Markasitschichte Dictyonema-Schiefer, Glaukonitsand, Gluakonitkalk1958295-6389405EmmonsE.1844Caroll and Cook edAlbany68 pGaucherC.PoireD.G.Gomez PeralL.ChiglinoL.Litoestratigrafia, bioestratigrafia y correlaciones de las sucesiones sedimentarias del Neoproterozoico-Cámbrico del Cratón del Río de La Plata (Uruguay y Argentina)200512145160HagadornJ. W.WaggonerB.Ediacaran fossils from the Southwestern Great Basin, United States200074349359https://doi.org/10.1666/0022-3360(2000)074<0349:EFFTSG>2.0.CO;2HahnG.HahnR.LeonardosO. H.PflugH. D.WaldeD.H.G.Korperlich erhaltene Scyphozoen - Reste aus dem Jungprakambrium Braziliens198216118HofmannH.J.AitkenJ.D.Precambrian biota from the Little Dal Group, Mackenzie Mountains, northwestern Canada197916150166https://doi.org/10.1139/e79-014HofmannH.J.MountjoyE.W.Namacalathus-Cloudina assemblage in Neoproterozoic Miette Group (Byng Formation), British Columbia: Canada’s oldest shelly fossils20012910911094https://doi.org/10.1130/0091-7613(2001)029<1091:NCAINM>2.0.CO;2KontorovichA.E.SokolovbB.S.KontorovichV. A.VarlamovA. I.GrazhdankinD.V.EfimovA.S.KletsA.G.SaraevS.V.TerleevA.A.BelyaevS.Yu.VaraksinaI.V.KarlovaG.A.KochnevB.B.NagavitsinK.E.PostnikovA.A.FilippovYu. F.The first section of Vendian deposits in the Basement Complex of the West Siberian Petroleum Megabasin (resulting from the drilling of the Vostok-3 parametric borehole in the Eastern Tomsk Region)2009425219222https://doi.org/10.1134/S1028334X09020093NaumovaS.N.Spores from the lower Cambrian194944956[in Russian]ParryL.BoggianiP.C.CondonD.GarwoodR.LemeJ.M.McIlroyD.BrasierM.D.TrindadeR.CampanhaG.A.C.PachecoM.L.A.F.DinizC.Q.C.LiuA.G.Ichnological evidence for meiofaunal bilaterians from the terminal Ediacaran and earliest Cambrian of Brazil2017114551464https://doi.org/10.1038/s41559-017-0301-9RouaultM.Note préliminaire sur une nouvelle formation découverte dans la terrain silurien inférieur de la Bretagne18507724744série 2SmithE.F.NelsonL.L.TweedtS.M.ZengH.WorkmanJ.B.A cosmopolitan late Ediacaran biotic assemblage: new fossils from Nevada and Namibia support a global biostratigraphic link201728420170934https://doi.org/10.1098/rspb.2017.0934SommerE.W.Microfósseis do calcário Bambuí, de Pedro Leopoldo, Estado de Minas Gerais197143135139TimofeevB.V.1966NaukaLeningrad147 pEnglish translation 1974, British Library-Landing Div., London, 214 p.TimofeevB.V.HermannT.N.MikhaylovaN.S.1976107 ppNaukaLeningrad[in Russian]UchmanA.Ichnology of the Rhenodanubian flysch (Lower Cretaceous-Eocene) in Austria and Germany19992565171UchmanA.Eocene flysch trace fossils from the Hecho Group of the Pyrenees, northern Spain200128341VidalG.Late Precambrian microfossils from the Visingso beds in southern Sweden19769157WalcottC.D.Precambrian fossiliferous formations189919199244https://doi.org/10.1130/GSAB-10-199WarrenL.V.FairchildT.R.GaucherC.BoggianiP.C.PoiréD.G.AnelliL.E.InchaustiJ.C.G.Corumbella and in situ Cloudina in association with thrombolites in the Ediacaran Itapucumi Group, Paraguay201123382389https://doi.org/10.1111/j.1365-3121.2011.01023.xWarrenL.V.SimoesM.G.FairchildT.R.RiccominiC.GaucherC.AnelliL. E.FreitasB. T.BoggianiP.C.QuaglioF.Origin and impact of the oldest metazoan bioclastic sediments201341507510https://doi.org/10.1130/G33931.1WarrenL.V.QuaglioF.RiccominiC.SimõesM.G.PoiréD.G.StrikisN.M.AnelliL.E.StrikisP.C.The puzzle assembled: Ediacaran guide fossil Cloudina reveals an old proto-Gondwana seaway201442391394https://doi.org/10.1130/G35304.1WarrenL.V.QuaglioF.SimõesM.G.GaucherC.RiccominiC.PoiréD.G.FreitasB.T.PauloC.Boggiani & SialA.N.Cloudina-Corumbella-Namacalathus association from the Itapucumi Group, Paraguay: Increasing ecosystem complexity and tiering at the end of the Ediacaran20172987987https://doi.org/10.1016/j.precamres.2017.05.003WarrenL.V.FreitasB.T.RiccominiC.BoggianiP.C.QuaglioF.SimõesM.G.FairchildT.R.GiorgioniM.GaucherC.PoiréD.G.CáceresA.A.SialA.N.Sedimentary evolution and tectonic setting of the Itapucumi Group, Ediacaran, northern Paraguay: From Rodinia break-up to West Gondwana amalgamation201932299121https://doi.org/10.1016/j.precamres.2018.12.022ZaineM.F.1991PhDUniversity of São PauloZangW.WalterM.R.Late Proterozoic and early Cambrian microfossils and biostratigraphy, northern Anhui and Jiangsu, central-eastern China199257243323https://doi.org/10.1016/0301-9268(92)90004-8