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Silicified microbiota from the Paleoproterozoic Dahongyu Formation, Tianjin, China

  • Min Shi (a1), Qing-Lai Feng (a1), Maliha Zareen Khan (a1), Stanley Awramik (a2) and Shi-Xing Zhu (a3)...
Abstract
Abstract

Cherts and silicified dolostones of the ca. 1600 Ma Dahongyu Formation (uppermost Changcheng Group) from North China contain well-preserved microfossils. Cyanobacteria filaments and coccoids dominate the studied Dahongyu microbiota in the Jixian section. These microfossils show the characteristics of endobenthic, epibenthic, and allochthonous microfossils, which illustrated well a vertical distributional view of an intertidal microbiota. Large numbers and size of allochthonous microfossils are the distinguishing characteristics of this new microbiota. A few of these possess ornaments or odd morphology, which suggest their potential eukaryotic nature. Through regional comparisons, it is revealed that there was significant regional disparity within the Yanshan Basin of microbiotas during deposition of the Dahongyu Formation. The newly studied Dahongyu microbiota is similar to the microbiota from the underlying Changcheng Group, with only slight differences. The absence of typical eukaryotes and the emergence of unique microfossils (especially small fusiform microfossils) make the Dahongyu Formation and the subsequent strata of the Jixian Group distinct from contemporaneous eukaryote-bearing strata.

In the Dahongyu assemblage, 19 species were recognized, six species were identified informally and seven species were identified in open nomenclature. One new taxon of microfossil was described: Xiaohongyuia sinica Shi and Feng new genus new species.

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Adam Z.R., Skidmore M.L., and Mogk D.W., 2016, Paleoenvironmental implications of an expanded microfossil assemblage from the Chamberlain Formation, Belt Supergroup, Montana, in MacLean, J.S., and Sears, J.W., eds., Belt Basin: Window to Mesoproterozoic Earth: Geological Society of America Special Paper, v. 522, p. 101–119. doi: 10.1130/2016.2522(04).
Agić H., Moczydłowska M., and Yin L.M., 2015, Affinity, life cycle, and intracellular complexity of organic-walled microfossils from the Mesoproterozoic of Shanxi, China: Journal of Paleontology, v. 89, p. 2850.
Andreeva E.M., et al., 1966, Palaeopalynology: Trudy Vsesoyuznogo Neftyanogo Nauchno-Issledovatel’skogo Geologorazvedochnogo Instituta (VNIGNI), v. 141, p. 114135.
Awramik S.M., and Barghoorn E.S., 1977, The Gunflint microbiota: Precambrian Research, v. 5, p. 121142.
Butterfield N.J., 2007, Macroevolution and macroecology through deep time: Palaeontology, v. 50, p. 4155.
Butterfield N.J., Knoll A.H., and Swett K., 1994, Paleobiology of the Neoproterozoic Svanbergfjellet Formation, Spitsbergen: Fossils and Strata, no. 34, Oslo, Scandanavian University Press, 84 p.
Campbell I.H., and Allen C.M., 2008, Formation of supercontinents linked to increases in atmospheric oxygen: Nature Geoscience, v. 1, p. 554558.
Cao F., 2005, A new type of primary unicellular microfossils from the chert of the Gaoyuzhuang Formation in Jixian County, Tianjin: Acta Geoscientica Sinica, p. 547551. [in Chinese with English summary].
Cavalier-Smith T., 2002, The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa: International Journal of Systematic and Evolutionary Microbiology, v. 52, p. 297354.
Chu X., Zhang T., Zhang Q., and Lyons T.W., 2007, Sulfur and carbon isotope records from 1700 to 800Ma carbonates of the Jixian section, northern China: implications for secular isotope variations in Proterozoic seawater and relationships to global supercontinental events: Geochimica et Cosmochimica Acta, v. 71, p. 46684692.
Elenkin A.A., 1936-1949. Monographia algarum cyanophycearum aquidulcium et terrestrium in finibus URSS inventarum [Sinezelenye vodorosli SSSR]: Moscow, AN SSSR, 1908 p. [in Russian].
Evitt W.R., 1963, A discussion and proposals concerning fossil dinoflagellates, hystrichospheres and acritarchs: Proceedings of the National Academy of Seiences USA, v. 49, p. 298–302.
Gao L.Z., Zhang C.H., Yin C.Y., Shi X.Y., Wang Z.Q., Liu Y.M., Liu P.J., Tang F., and Song B., 2008, SHRIMP zircon ages: basis for refining the chronostratigraphic classification of the Meso- and Neoproterozoic strata in North China old land: Acta Geoscientica Sinica, v. 29, p. 366376. [in Chinese with English summary].
Gao L.Z., Zhang C.H., Liu P.J., Ding X.Z., Wang Z.Q., and Zhang Y.J., 2009, Recognition of Meso- and Neoproterozoic stratigraphic framework in north and south China: Acta Geoscientica Sinica, v. 30, p. 433446. [in Chinese with English summary].
Guo H., Du Y.S., Zhou L., Yang J.H., and Huang H., 2012, Isotopic composition of organic and inorganic carbon from the Mesoproterozoic Jixian Group, North China: implications for biological and oceanic evolution: Precambrian Research, v. 224, p. 169183.
Holland H.D., 2006, The oxygenation of the atmosphere and oceans: Philosophical Transactions of the Royal Society B: Biological Sciences, v. 361, p. 903915.
Horodyski R.J., and Donaldson A.J., 1980, Microfossils from the Middle Proterozoic Dismal Lakes Groups, Arctic Canada: Precambrian Research, v. 11, p. 125159.
Hu Y., and Fu J., 1982, Micropalaeoflora from the Gaoshanhe Formation of Late Precambrian of Luonan, Shaanxi and its stratigraphic significance: Bulletin of the Xi’an Institute of Geology and Mineral Resources, Chinese Academy of Geological Science, v. 4, p. 102113. [in Chinese with English summary].
Jankauskas T.V., Mikhailova N.S., and Hermann T.N., eds., 1989, Precambrian Microfossils of the USSR: Leningrad, Nauka, 191 p. [in Russian].
Javaux E.J., and Marshal C.P., 2006, A new approach in deciphering early protist paleobiology and evolution: combined microscopy and microchemistry of single Proterozoic acritarchs: Review of Palaeobotany and Palynology, v. 139, p. 115.
Javaux E.J., Knoll A.H., and Walter M.R., 2001, Morphological and ecological complexity in early eukaryotic ecosystems: Nature, v. 412, p. 6669.
Javaux E.J., Beghin J., Houzay J.P., and Blanpied C., 2013, The “boring billion”: an exciting time for early eukaryotes! (Goldschmidt Conference Abstracts): Mineralogical Magazine, 77, p. 1380. Kirchner, O., 1900, Shizophyceae, in Engler, A., and Prantl, K., eds., Die natürlichen Pflanzenfamilien: Leipzig, I Teil, Abteilung Ia, p. 115–121.
Knoll A.H., 1982, Microfossils from the late Precambrian Draken Conglomerate, Ny Friesland, Svalbard: Journal of Paleontology, v. 56, p. 755790.
Knoll A.H., and Barghoorn E.S., 1976, A Gunflint-type microbiota from the Duck Creek dolomite, Western Australia: Origins of life, v. 7, p. 417423.
Knoll A.H., and Calder S., 1983, Microbiotas of the late Precambrian Ryssö Formation, Nordaustlandet, Svalbard: Palaeontology, v. 26, p. 467496.
Knoll A.H., and Golubic S., 1979, Anatomy and taphonomy of a Precambrian algal stromatolite: Precambrian Research, v. 10, p 115151.
Knoll A.H., Swett K., and Burkhardt E., 1989, Paleoenvironmental distribution of microfossils and stromatolites in the Upper Proterozoic Backlundtoppen Formation, Spitsbergen: Journal of Paleontology, v. 63, p. 129145.
Knoll A.H., Swett K., and Mark J., 1991, Paleobiology of a Neoproterozoic tidal flat/lagoonal complex: the Draken Conglomerate Formation, Spitsbergen: Journal of Paleontology, v. 65, p. 531570.
Knoll A.H., Javaux E.J., Hewitt D., and Cohen P., 2006, Eukaryotic organisms in Proterozoic oceans: Philosophical Transactions of the Royal Society B: Biological Sciences, v. 361, p. 10231038.
Lamb D.M., Awramik S.M., Chapman D.J., and Zhu S.X., 2009, Evidence for eukaryotic diversification in the 1800 million-year-old Changzhougou Formation, North China: Precambrian Research, v. 173, p. 93–104.
Lanier W.P., 1989, Interstitial and peloid microfossils from the 2.0 Ga Gunflint Formation: implications for the paleoecology of the Gunflint stromatolites: Precambrian Research, v. 45, p. 291318.
Lee S.J., and Golubic S., 1998, Multi-trichomous cyanobacterial microfossils from the Mesoproterozoic Gaoyuzhuang Formation, China: paleoecological and taxonomic implications: Lethaia, v. 31, p. 169184.
Li H.K., Lu S.N., Li H.M., Sun L.X., Xiang Z.Q., Geng J.Z., and Zhou H.Y., 2009, Zircon and beddeleyite U-Pb precision dating of basic rock sills intruding Xiamaling Formation, North China: Geological Bulletin of China, v. 28, p. 13961404. [in Chinese with English summary].
Li H.K., Zhu S.X., Xiang Z.Q., Su W.B., Lu S.N., Zhou H.Y., Geng J.Z., Li S., and Yang F.J., 2010, Zircon U-Pb dating on tuff bed from Gaoyuzhuang Formation in Yanqing, Beijing: further constraints on the new subdivision of the Mesoproterozoic stratigraphy in the northern North China Craton: Acta Petrologica Sinica, v. 26, p. 21322140. [in Chinese with English summary].
Li H.K., Su W.B., Zhou H.Y., Geng J.Z., Xiang Z.Q., Cui Y.R., Liu W.C., and Lu S.N., 2011, The base age of the Changchengian System at the northern North China Craton should be younger than 1670 Ma: constraints from zircon U-Pb LA-MC-ICPMS dating of a granite-porphyry dike in Miyun County, Beijing: Earth Science Frontiers, v. 18, p. 108120. [in Chinese with English summary].
Li H.K., Su W.B., Zhou H.Y., Xiang Z.Q., Tian H., Yang L.G., Huff W.D., and Ettensohn F.R., 2014, The first precise age constraints on the Jixian System of the Meso- to Neoproterozoic standard Section of China: SHRIMP zircon U-Pb dating of bentonites from the Wumishan and Tieling formations in the Jixian section, North China Craton: Acta petrologica Sinica, v. 30, p. 29993012. [in Chinese with English summary].
Li M., Liu P., Yin C., Tang F., Gao L., and Chen S., 2012, Acritarchs from the Baicaoping Formation (Ruyang Group) of Henan: Acta Palaeontological Sinica, v. 51, p. 7687. [in Chinese with English summary].
Licari G.R., and Cloud P.E., 1968, Reproductive structures and taxonomic affinities of some nannofossils from the gunflint iron formation: Proceedings of the National Academy of Sciences of the United States of America, v. 59, p. 1053–1060. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC224829/
Lu S.N., and Li H.M., 1991, A precise U-Pb single zircon age determination for the volcanics of Dahongyu Formation Changcheng system in Jixian: Bulletin of the Chinese Academy of Geological Sciences, v. 22, p. 137146. [in Chinese with English summary].
Lu S.N., Yang C.L., Li H.K., and Chen Z.H., 2002, North China continent and Columbia supercontinent: Earth Science Frontiers, v. 9, p. 225233. [in Chinese with English summary].
Lu S.N., Li H.K., Chen Z.H., Yu H.F., Jin W., and Guo K.Y., 2004, Relationship between Neoproterozoic cratons of China and the Rodinia: Earth Science Frontiers, v. 11, p. 515523. [in Chinese with English summary].
Mendelson C.V., and Schopf J.W., 1982, Proterozoic microfossils from the Sukhaya Tunguska, Shorikha, and Yudoma formations of the Siberian Platform, USSR: Journal of Paleontology, v. 56, p. 4283.
Moczydłowska M., Landing E.D., Zang W.L., and Palacios T., 2011, Proterozoic phytoplankton and timing of Chlorophyte algae origins: Palaeontology, v. 54, p. 721733.
Monty C.L., 1976, The Origin and Development of Cryptalgal Fabrics, in Walter M.R., ed., Stromatolites: Developments in Sedimentology: Amsterdam, Elsevier, v. 20, p. 193249.
Nägeli C., 1849, Gattungen Einzelliger Algen, Physiologisch und Systematisch Bearbeitet: Zürich, F. Schulthess, 139 p.
Noffke N., 2010, Geobiology: Microbial Mats in Sandy Deposits from the Archean Era to Today: Heidelberg, Springer, 196 p.
Oehler D.Z., 1978, Microflora of the middle Proterozoic Balbirini Dolomite (McArthur Group) of Australia: Alcheringa, v. 2, p. 269309.
Oehler J.H., 1977, Microflora of the H.Y.C. Pyritic Shale Member of the Barney Creek Formation (McArthur Group), middle Proterozoic of northern Australia: Alcheringa, v. 1, p. 315349. Peng, Y.B., Wang, D., and Yuan, X.L., 2007, Ultrastructure of spheroidal acritarchs from the Chuanlinggou Formation of the Changcheng System: Acta Micropalaeontologica Sinica, v. 24, p. 194–204. [in Chinese with English summary].
Peng Y.B., Bao H.M., and Yuan X.L., 2009, New morphological observations for Paleoproterozoic acritarchs from the Chuanlinggou Formation, North China: Precambrian Research, v. 168, p. 223232.
Planavsky N.J., Reinhard C.T., Wang X.L., Thomson D., Mcgoldrick P., Rainbird R.H., Johnson T., Fischer W.W., and Lyons T.W., 2014, Low Mid-Proterozoic atmospheric oxygen levels and the delayed rise of animals: Science, v. 346, p. 635–638.
Porter S.M., Meisterfeld R., and Knoll A.H., 2003, Vase-shaped microfossils from the Neoproterozoic Chuar Group, Grand Canyon: a classification guided by modern testate amoebae: Journal of Paleontology, v. 77, p. 409429.
Ren F.G., 1987, The essential character of volcanic-sedimentary rocks of Dahongyu Formation in Jixian: Bulletin Tianjin Institute of Geology and Mineral Resources, v. 16, p. 91106. [in Chinese with English summary].
Santosh M., 2010, A synopsis of recent conceptual models on supercontinent tectonics in relation to mantle dynamics, life evolution and surface environment: Journal of Geodynamics, v. 50, p. 116133.
Schopf J.W., 1968, Microflora of the Bitter Springs formation, late Precambrian, central Australia: Journal of Paleontology, v. 42, p. 651688.
Schopf J.W., and Blacic J.M., 1971, New microorganisms from the Bitter Springs Formation (late Precambrian) of the north-central Amadeus Basin, Australia: Journal of Paleontology, v. 45, p. 925960.
Sergeev V.N., Knoll A.H., and Grotzinger J.P., 1995, Paleobiology of the Mesoproterozoic Billyakh Group, Anabar Uplift, Northern Siberia: Memoir (The Paleontological Society), v. 69, p. 137.
Sharma M., 2006, Palaeobiology of Mesoproterozoic Salkhan Limestone, Semri Group, Rohtas, Bihar, India: systematics and significance: Journal of Earth System Science, v. 115, p. 6798.
Shepeleva E.D., 1963, Spore (?) Complexes in deposits of the Bavlinskoy Series of the Volga-Ural area, in Filimonova, A.B., and Archangelskaya A.D., eds., Spore-pollen Complexes and Stratigraphy of the Upper Proterozoic, Paleozoic and Mesozoic of the Volga-Uragarea and Central Asia: Trudy Vsesoyunogo Nauchno-Issledovatelskogo Geologorazvedochnogo Neftyanogo Instituta (VNIGNI), v. 37, p. 716.
Shi M., Feng Q.L., and Zhu S.X., 2014, Biotic evolution and its relation with geological events in the Proterozoic Yanshan Basin, North China: Science China: Earth Sciences, v. 57, p. 903918.
Stanier R.Y., et al., 1978, Proposal to place the nomenclature of the cyanobacteria (blue-green algae) under the rules of the International Code of Nomenclature of Bacteria: International Journal of Systematic and Evolutionary Microbiology, v. 28, p. 335336.
Su W.B., Li H.K., Huff W.D., Ettensohn F.R., Zhang S.H., Zhou H.Y., and Wan Y.S., 2010, SHRIMP U-Pb dating for a K-bentonite bed in the Tieling Formation, North China: Chinese Science Bulletin, v. 55, p. 33123323. [in Chinese with English summary].
Sun S.F., 2006, Microfossils in the Meso- Neoproterozoic Jixian section, China: Beijing, Geological Publishing House, p. 160 [in Chinese].
Teyssèdre B., 2006, Are the green algae (phylum Viridiplantae) two billion years old?: Carnets de Géologie/Notebooks on Geology: 2006/03. http://paleopolis.rediris.es/cg/CG2006_A03/index.html
Thuret G., 1875, Essai de classification des Nostochinées: Annales des sciences naturelles (Botanique), v. 6, p. 372382.
Timofeev B.V., 1966, Micropaleophytological lnvestigations of Ancient Suites: Moscow, Nauka, 147 p.
Tobin K.J., 1990, The paleoecology and significance of the Gunflint-type microbial assemblages from the Frere Formation (Early Proterozoic), Nabberu Basin, Western Australia: Precambrian Research, v. 47, p. 7181.
Vorob’eva N.G., Sergeev V.N., and Petrov P.Y., 2015, Kotuikan Formation assemblage: a diverse organic-walled microbiota in the Mesoproterozoic Anabar succession, northern Siberia: Precambrian Research, v. 256, p. 201222.
Wettstein R., 1924, Handbuch der Systematischen Botanik: Leipzig, Franz Deuticke, v. 1, 467 p.
Woese C.R., and Fox G.E., 1977, Phylogenetic structure of the prokaryotic domain: the primary kingdoms: Proceedings of the National Academy of Sciences, v. 74, p. 5088–5090.
Xiao S., Knoll A.H., Kaufman A.J., Yin L., and Zhang Y., 1997, Neoproterozoic fossils in Mesoproterozoic rocks? Chemostratigraphic resolution of a biostratigraphic conundrum from the North China Platform: Precambrian Research, v. 84, p. 197220.
Xing Y.S., and Liu G.Z., 1973, The Sinian microfossils from Yanshan area and its geological significance: Acta Geologica Sinica, v. 47, p. 151. [in Chinese with English summary].
Xu D.B., Bai Z.D., Wang D.Z., Mei M.X., and Li Z.Z., 2002a, On sedimentary environment of the Dahongyu Formation in Xinglong region, Heibei: Journal of Stratigraphy, v. 26, p. 7379. [in Chinese with English summary].
Xu D.B., Wang D.Z., Bai Z.D., Mei M.X., and Li Z.Z., 2002b, Sedimentary environment and facies model of the Mesoproterozoic Chuanlinggou Formation in the Xinglong area, Hebei: Chinese Geology, v. 29, p. 167171. [in Chinese with English summary].
Yan Y.Z., 1982, Schizofusa from the Chuanlinggou Formation of Changcheng System in Jixian County: Bulletin Tianjin Institute of Geology and Mineral Resources, v. 6, p. 17. [in Chinese with English summary].
Yan Y.Z., 1985, Preliminary research on microflora from Chuanlinggou Formation of Changcheng System in Jixian County: Bulletin Tianjin Institute of Geology and Mineral Resources., v. 12, p. 137168. [in Chinese with English summary].
Yan Y.Z., 1991, Shale-facies microflora from the Changzhougou Formation (Changcheng System) in Pangjiapu region, Hebei, China: Acta Micropalaeontologica Sinica, v. 8, p. 183191. [in Chinese with English summary].
Yan Y.Z., and Liu Z.L., 1993, Significance of eukaryotes organisms in the microfossil flora of Changcheng System: Acta Micropalaeontologica Sinica, v. 10, p. 167180. [in Chinese with English summary].
Yan Y.Z., and Liu Z.L., 1998, Does Sangshuania represent eukaryotic algae or trace fossils?: Acta Micropalaeontologica Sinica, v. 15, p. 101110. [in Chinese with English summary].
Yin L.M., 1985, Microfossils from Precambrian rocks of the Dahongyu Formation of Jixian, North China: Acta Palaeontologica Sinica, v. 24, p. 111115. [in Chinese with English summary].
Young G.M., 2013, Secular changes at the Earth’s surface; evidence from palaeosols, some sedimentary rocks, and palaeoclimatic perturbations of the Proterozoic Eon: Gondwana Research, v. 24, p. 453467.
Zhang P.Y., and Yan X.L., 1984, Microfossil from the Gaoyuzhuang Formation in Laishui County, Hebei, China: Acta Geologica Sinica, v. 58, p. 196203. [in Chinese with English summary].
Zhang S.H., Li Z.X., Evans D., Wu H.C., Li H.Y., and Dong J., 2012, Pre-Rodinia supercontinent Nuna shaping up: a global synthesis with new paleomagnetic results from North China: Earth and Planetary Science Letters, v. 353, p. 145155.
Zhang Y., 1981, Proterozoic Stromatolite Microfloras of the Gaoyuzhuang Formation (Early Sinian: Riphean), Hebei, China: Journal of Paleontology, v. 55, p. 485506.
Zhang Y., 1984, A Gunflint type of microfossil assemblage from early Proterozoic stromatolitic cherts in China: Nature, v. 309, p. 547549.
Zhang Y., 1985, Stromatolitic microbiota from the Middle Proterozoic Wumishan Formation (Jixian Group) of the Ming Tombs, Beijing, China: Precambrian Research, v. 30, p. 277302.
Zhang Y., 1988, Proterozoic stromatolitic micro-organisms from Hebei, North China: cell preservation and cell division: Precambrian Research, v. 38, p. 165175.
Zhang Y., and Golubic S., 1987, Endolithic microfossils (cyanophyta) from early Proterozoic stromatolites, Hebei, China: Acta Micropalaeontologica Sinica, v. 4, p. 112. [in Chinese with English summary].
Zhang Y., Yang C.Y., Yin C.H., and Shao C.X., 1995, Microbial mat communities and related sedimentary-geochemical aspects of the Mesoproterozoic Changcheng Group, Pangjiapu, Hebei, North China: Acta Micropalaeontologica Sinica, v. 12, p. 221240. [in Chinese with English summary].
Zhang Z.Y., and Li Z.H., 1984, Noctidiurnal growth rhythm of filamentous cyanophytes from the Gaoyuzhuang Formation (Changcheng System) of North China: Chinese Science Bulletin, v. 29, p. 640 [in Chinese with English summary].
Zhang Z.Y., and Liu S., 1991, Post-burial contraction cracks in Precambrian acritarchs: Chinese Science Bulletin, v. 36, p. 400403. [in Chinese with English summary].
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