Dorjnamjaa et al. Mongolian Geoscientist 49 (2019) 41-49 https://doi.org/10.5564/mgs.v0i49.1226
New scientific direction of the bacterial paleontology in Mongolia: an essence of investigation Dorj Dorjnamjaa*, Gundsambuu Altanshagai, Batkhuyag Enkhbaatar
Department of Paleontology, Institute of Paleontology, Mongolian Academy of Sciences, Ulaanbaatar 15160, Mongolia
*Corresponding author. Email: [email protected]
ARTICLE INFO ABSTRACT Article history: We review the initial development of Bacterial Paleontology in Mongolia and Received 10 September 2019 present some electron microscopic images of fossil bacteria in different stages of Accepted 9 October 2019 preservation in sedimentary rocks. Indeed bacterial paleontology is one the youngest branches of paleontology. It has began in the end of 20th century and has developed rapidly in recent years. The main tasks of bacterial paleontology are detailed investigation of fossil microorganisms, in particular their morphology and sizes, conditions of burial and products of habitation that are reflected in lithological and geochemical features of rocks. Bacterial paleontology deals with fossil materials and is useful in analysis of the genesis of sedimentary rocks, and sedimentary mineral resources including oil and gas. The traditional paleontology is especially significant for evolution theory, biostratigraphy, biogeography and paleoecology; however bacterial paleontology is an essential first of all for sedimentology and for theories sedimentary ore genesis or biometallogeny
INTRODUCTION all the microorganisms had lived and propagated Bacteria or microbes preserved well as fossils in without breakdowns. Bacterial paleontological various rocks, especially in sedimentary rocks data accompanied by the data on the first origin alike natural substances. Major types of of eukariotes, metazoan, etc. The essential role sedimentary rocks form in the photic zone of of bacteria and other microbes in the geological epicontinental basins of the past, originated and biological processes was proposed long ago. under influence of microorganisms. Photic zone, Many specialists of the 19th century claimed that surface layer of the ocean receives sunlight. The there is a tremendous role of bacteria in the uppermost 80 m or more of the ocean, which is formation of the sedimentary mineral resources, sufficiently illuminated to permit photosynthesis like phosphorite, bauxite, iron ores, oil, by phytoplankton and plants, is called the hydrocarbon, petroleum gas, gold, sulfide, sulfur euphotic zone? Within these oceanic expances, and sulfate, etc. The most significant break-
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Dorjnamjaa et al. Mongolian Geoscientist 49 (2019) 41-49 through was made after the introduction of Dorjnamjaa, 2017; Anderson et al., 2017a, b, electron microscopy to the study of microbial 2018). In Mongolia the oldest microorganisms remains. Mongolian bacterial fossils from from the Paleoproterozoic were found in the Precambrian and Cambrian sedimentary rocks iron-bearing quartzite. In 1981, B.V.Timofeev and bedded phosphorite were examined using a (Russian palynologist of Leningrad Institute of Zeiss EVO50 SEM with an Oxford INCA the Precambrian geology and geochronology, microanalyzer (Energy 350) at the RAS, who pioneered the study of Precambrian Paleontological Institute of the Russian an Early Paleozoic acritarchs) described and Academy of Sciences were published repeatedly published several new genera and species of (Zhegallo et al., 2000). According to acritarchs (Protosphaeridium sp., A.Yu.Rozanov a start of forming of the bacterial Gloeocapsomorpha priscata Tim., paleontology was kick-off research of the Trematosphaeridium sp., etc). These bacterial Mongolian phosphorite (Rozanov, 2016). New microfossils of the “bodaibin” type were scientific technology revealed that almost all extracted from Khangiltsig metacomplex sedimentary rocks contain micro-scale bacteria. (Khankhukhei block). Also T.N.German The main task for bacterial paleontology is to together with B.V.Timofeev have described study the fossil microbes. The traditional number of bacterial fossils (Spheromorphides, paleontology deals with remains of ancient Filamentous algae, etc.) from Meso- organisms. As known the main “users” of Neoproterozoic sedimentary and paleontology are the evolutionary theory, the metaargillaceous rocks of the Tseel, Baidrag and history of organic world and the biostratigraphy. Tarvagatai blocks (Mitrofanov et al., 1981). The Bacterial paleontology or geomicrobiology is presence of cyanobacteria in all mentioned limited in its input data by the simplicity of the rocks could be considered as a reliable fact. objects’ morphology and specificity in Also it has importance for paleogeography and systematization of the bacterial material. So, the paleoecology in the study of epicontinental bacterial paleontology is very important for basins as Khuvsgul and Zavkhan shallow basins sedimentology, and consequently for detailed in Mongolia (Ragozina et al., 2010; study of the geneses of sedimentary mineral Serezhnikova et al., 2014). The Khuvsgul and resources, including oil, gas, iron, phosphate, Zavkhan basins host economic-grade and gold. Geomicrobiology is a scientific field phosphorite deposits (Ilyin, 1973; Dorjnamjaa at the intersection of geology and microbiology and Soyolmaa, 2001). The high preservation (Dorjnamjaa et al., 2018, 2019). It concerns the potential of organic microfossils in phosphorites effect of microbes on geological and makes Mongolia an obvious target for new geochemical processes and vice versa. Such Lagerstatten, which might inform the debate interactions occur in the geosphere (rocks, about the phylogenetic affinities of these early minerals, soils, and sediments), the atmosphere organisms (Anderson et al., 2018). Just and the hydrosphere. All kinds of microbes, Anderson et al., (2018) have recently presented including prokaryotes and eukaryotes and their systematic palaeontology of the recently symbiotic associations with each other and discovered Kheseen Lagerstatten, which higher organisms, can contribute actively to includes Doushantuo-Pertatataka-type geological phenomena, and central to many acanthomorphs and other microfossils, including such geomicrobial processes are transformations animal embryo-like forms, and discussed its of metals and minerals. biostratigraphical and palaeobiological Indeed a diverse Proterozoic-Phanerozoic significance. A Lagerstatten (German:from sedimentary stratigraphic rocks in Mongolia storage, place) is a sedimentary deposit that record and faunal, floral, and also bacterial exhibits extraordinarily preserved fossils with localities (Mitrofanov et al., 1981; Dorjnamjaa exceptional preservation, which sometimes and Bat-Ireedui, 1991, Bosak et al., 2011a, b; include preserved soft tissues. These formations Barsbold and Byamba, 2012; Byamba, 2012; may have resulted from carcass like burial in an Dorjnamjaa, 2016; Dorjnamjaa et al., 2016; anoxic environment with minimal bacteria, thus
42 Dorjnamjaa et al. Mongolian Geoscientist 49 (2019) 41-49 delaying the decomposition of both gross and Archaeooides sp., Acanthomorphs, Mega- fine biological features until long after a sphaera, Archaeophycus, so on). The lower durable impression was created in the Cambrian Bayangol and Salaanygol formations surrounding matrix. Lagerstatten span within the Khasagt Khairkhan mountain and geological time from the Neoproterozoic era to Zavkhan river area contain abundant trace the present. Worldwide, some of the best fossils (Goldring et al., 1996), stromatolite examples of near-perfect fossilization and (thrombolites), soft-bodied fossils (Spatangopsis world’s major Lagerstatten are the Precambrian mongolica, Paracharnia, Oldhamia radiata), Bitter Springs (1000-850 Ma, Southern medusoid (jellyfish) and small shelly fossils: Australia), Doushantuo Formation (600-555 protoconodonts, anabaritids, cap-shaped fossils, Ma, China), Mistaken Point (565 Ma, Salanacus, hyolithelminthes, coelosclerito- Newfoundland, Canada), Ediacara Hills (550- phorans, tommotiids, orthothecimorphs, 545 Ma, Southern Australia), White Sea (550 molluscs and calcareous brachiopods (Zhegallo Ma, Northwest Coast of Russia), the Cambrian et al., 2000; Dorjnamjaa et al., 2016; Anderson Burgess Shale (505 Ma, British Columbia, et al., 2018). Trilobites and Archaeochyathids Canada), Wheeler Shale (507 Ma, Western are confined to the Salaanygol Formation in Utah,USA), Emu Bay Shale (525 Ma, Southern Zavkhan area, Salaanygol section and Australia), the Devonian Hunsrick Slates and Erkhelnuur Formation (Kheseengol, Ongoliggol Gogo Formation, the Carboniferous Mazon and Urandush sections) in western Coast of Creek, the Jurassic Solnhofen limestone, the Khuvsgul Lake and Egiingol Formation (Myaras Cretaceous Santana, Yixian and Tanis ovoo section, Blue Montain section, Chuulgant formations, the Eocene Green River Formation, mountain section near the East Khargana river), and the Miocene Foulden Maar, so on. Khoridulin, Jamatulingol and Ujiggol We are fully conscious of the fact that formations in western and southern Khuvsgul microfossil assemblages of the acritarchs, area (Dorjnamjaa et al., 1982). known from Proterozoic-Lower Cambrian strata are commonly found in shale and chert, as well RESULTS as carbonaceous lithologies that are sufficiently The highest significance of bacterial phosphatized (Zhegallo et al., 2000; Pruss et al., paleontological data is obvious for study of 2017; Anderson et al., 2018; Dorjnamjaa et al., biosphere evolution, especially in the 2018). Bacterial fossils from the Late Precambrian and the early Paleozoic. And Proterozoic of Mongolia are known. The finally, bacterial paleontology is one of the Maikhan-Uul and Tsagaan-Olom formations in principle aspects for the astromaterials’ study the Zavkhan phosphate basin and Arasan, also (Dorjnamjaa et al., 2012). The recent electron- Kheseen Formation in Khuvsgul phosphate microscopic studies of rocks varying both in basin preserve diverse stromatolites, oncolites, chemical composition and age prove that sponge spicules, zooproblematica fossilized microorganisms can be practically (Archaeooides sp.), bacterial fossils found in almost all sedimentary rock. (Obruchevella sp., Siphonophycus sp., Bacterial fossils are the remains of animals or Tasmanites sp., Chuaria sp., Aspidella sp., plants that are preserved in rocks, that bacteria
Fig. 1. Bodaibin type bacterial microfossils (Spheromorphides).Paleoproterozoic Khangiltsig metacomplex, Khankhukhei block in western Mongolia. Natural size of the microfossils is overstated 600 times (after Mitrofanov et al., 1981).
43 Dorjnamjaa et al. Mongolian Geoscientist 49 (2019) 41-49 are neither plants nor animals. They belong to a bacteria. Modern bacteria’s ancestors-single group all by themselves. Bacteria, singular celled microorganisms-have appeared on the bacterium, any of a group of microscopic single- Earth about 4 billion years ago and were the celled organisms that live in enormous numbers very first form of life to exist on the Earth. For in almost every environment on Earth, from the following 3 billion years, all life forms on deep-sea vents to deep below Earth’s surface to the Earth were microscopic in size, and included the digestive tracts of humans. Hence, bacteria two dominant ones: 1. Bacteria, and 2. Archaea are the beginning of life and found everywhere (classified as bacteria, but genetically and such as the air, water, top-soil, high-temperature metabolically different from all other known springs, permafrost (frozen soils and rocks), bacteria). Bacteria come in three main shapes: 1. different types of ice, and shifting sands of spherical or coccoid (like a ball), 2. rod shaped desert. Scientists have discovered bacteria or vibrio, 3. spiral or spirochetes (Dorjnamjaa et growing in the hot springs of Yellowstone al., 2018). Precisely these rocks contain fantastic National Park, America, where the water preservation of diverse cyanobacteria and other reaches near boiling temperature. Bacteria have microorganisms (Figs. 1-10). been found deep inside ice above Lake Vostok On the whole, bacterium applies to an ordinary in the Antarctic. The Planet Earth is estimated to microscopic organism that consists of a single hold at least 5 nonillion (or 5x1030) bacteria. cell without noticeable nucleus, but possesses of Much of the Earth’s biomass is made up of colossal biochemical energy. Moreover, bacteria
Fig. 2. Obruchevella, A, B and D–G are photomicrographs from Fig. 3. 1-8. “Zavkhan biota” from the Ediacaran thin-sections; C is a scanning electron micrograph of an acid- Tsagaan-Olom phosphate-bearing Formation of the extracted specimen. In this and subsequent figure legends YPM Zavkhan basin, western Mongolia. 1-Tyraso- numbers are given, in addition to rock sample/thin-section thaeniapodolica Gnilovskaya, 1991, specimen PIN identifications and, where appropriate, England Finder no. 5492/7; 2-gr. forma Archaeooides sp. coordinates for all illustrated sedimentary structures, microfossils Tasmanites sp., specimen PIN 5492/8; 3- and populations. A, O. delicata, YPM 536750, M602 176.0 B, Octoedryxiumtruncatum Rud., 1989, specimen PIN E47/0; B, O. magna, YPM 536778, M618 33.0 A, F42/3; C, 5492/3; 4-Problematicum Navifusa sp., specimen O. magna, YPM 538075, from YPM 536747, M618 320; D, PIN 5492/9; 5-Tanarium sp., specimen PIN 5492/4; O. magna in cross-section, YPM 536779, M618 33.0 A, F42/3; E, 6-Tanarium sp., specimen PIN 5492/10; 7-8- O. parvissima, YPM 536792, M618 33.0 C, S59/3; F, O. Tallophycoides sp., fragments of lamellae, specimen parvissima, YPM 536793, M618 33.0 C, M60/0; G, O. valdaica, YPM 536780, M618 33.0 A, F42/3. Scale bars D 50 PIN 5492/11-12 (after Serezhnikova et al., 2014) mm (After Anderson et al., 2018). Khuvsgul phosphate basin, phosphate-bearing Kheseen Formation 44 Dorjnamjaa et al. Mongolian Geoscientist 49 (2019) 41-49
Fig. 6. New location of Spatangopsis mongolica Dorjnamjaa, phosphatic silty sandstone in the base of 18th bed of the Bayangol Formation indicative the limitotype boundary between Ediacaran and Lower Cambrian. Bayangol gorge. Photograph by D.Dorjnamjaa, 08.27.2017.
Fig. 4. 1-4- Problematical remains of Chuaria sp. and Aspidella-like imprint from the Tsagaan-Olom Formation of the Zavkhan phosphate basin, western Mongolia (modified after Ragozina et al., 2010). 5- Surface of fossiliferous layer, Tsagaan-Olom phosphate -bearing Formation (Dorjnamjaa et al., 2018).
Fig. 5. Mankhan-Uul phosphorite deposit, left-bank of Fig. 7. SEM images of phosphatic small shelly the Egiingol river. Problematical discoidal and circular fossils. A–D) Chancelloriid sclerites; E) hyoliths; F) bacterial remains of Chuaria sp. and Aspidella-like Possible hyolith; identification uncertain (After Pruss et imprint from the Kheseen Formation of the Khuvsgul al., 2017). Lower Cambrian, Salaanygol Formation phosphate basin. Photograph by D.Dorjnamjaa, 05.08.2019.
45 Dorjnamjaa et al. Mongolian Geoscientist 49 (2019) 41-49
Fig. 8. SEM images of phosphatized archaeocyaths. A) Branching archaeocyath. B–J) Internal molds of archaeocyaths. K) Archaeocyathan pore system. L) Archaeocyath replaced by apatite (after S.B. Pruss et al., 2017). Lower Cambrian, Salaanygol Formation.
Fig. 10. Petrographic image of thin section. Possible ball- like biomicrobodies (?) in the meteor Pallasite from Tsenkher astropipe crater. Thin section 11/06. Japanese microscope Nikon ECLIPSE E400 POL (Dorjnamjaa et al., 2012).
were accepted an active participation in process of decomposition and oxidation of organic Fig. 9. Petrographic images of thin sections. All matter. Here it should be emphasized that by the thinsections were made from the same hand samples as process of mineralization primary matter of those used for dissolutions. A) Apatite filling a calcareous archaeocyath. B) Calcareous archaeocyath (left) and skeleton and cyanobacterial mats are substituted calcareous archaeocyath filled with apatite (right). C) with other mineral matter or pseudomorphism. Phosphatized hyolithid (black arrow). D) Calcareous small The most prevailing bacteriogenic mineral shelly fossil. E) Possible phosphatic brachiopod shell in the matters are calcium, mineral carbon, mineral oil, center of the picture, and phosphatic cement (white arrow). F) Glauconitic cement (black arrow). (after Pruss et al., magnesium carbonate, phosphate, sulphide 2017). Lower Cambrian, Salaanygol Formation. (pyrite), oxides and hydroxyls (silica in different 46 Dorjnamjaa et al. Mongolian Geoscientist 49 (2019) 41-49 modification), and indigenous limonite. beginning of an life. The “Khuvsgul” and So the ancient phosphorites have become the ”Zavkhan” biota were mostly cyanobacterial. classic object for such studies (Dorjnamjaa, The cyanobacterial mat community was 2016). preserved in phosphorites in the form of a All kinds of bacteria can be an active stromatolite, microphytolite, blue-green algal contribution to geological phenomena, and remain, and micronodul side by side with centre of many such geomicrobial and trace and small shelly fossils (SSFs), also biometallogenical processes and transformation spiculate sponges. The micronodules are or bioremediation of metals and minerals. The clearly predominant in our observations. The deposits of sedimentary mineral resources give micronodule sizes usually vary from tens to clearly show another perfect paradigm of the several hundreds of microns (Archaeooides, tremendous bacterial role in the ancient Tasmanites, Obruchevella, Siphonophycus, geological event. The ancient phosphorites have Lagerstatten, so on). Soft-bodied animals become the classic object for such studies. resemble organisms such as coelenterates and Thirty years ago, we were aware of twenty annelids and may be early forms of these minerals that could originate with the microbial groups. In all probability, all the fossils are activity. In recent times, the number of such closely connected and intercommunicated by minerals grew significantly, and nowadays it is one’s genesis and accumulation in the ancient more than a hundred. Using new methodology phosphatic basins. This is a target for future and factual data we would like to introduce investigation. some sedimentary mineral resources (biogenic phosphorites, gold-forming black shale, uranium ACKNOWLEDGEMENT and oil-gas deposits) those could be formed with We thank Dr. C.B.Skovsted, leader of the the significant assistance of bacterial Mongolian-Sweden Paleontological Project microfossils. In addition to above mentioned “The Ediacaran-Cambrian evolution of biota phosphorites, iron ores, graphite, and rare metal (SSFs, Ichnofossils, Soft-bodied fossils and ores, bauxites, sulfides, gold, etc. are Bacterial fossils) in the Zavkhan and Khuvsgul noteworthy (Dorjnamjaa et al., 2018). basins of Mongolia” in 2017-2019 who organized the logistics and all the expenses in CONCLUSION Zavkhan and Khuvsgul phosphate basins. This 1. Summing up all that has been said, in joint research benefited from discussions with conclusion of our paper using new Dr. M.J.Betts (Australia), Dr. T.P.Topper methodology and factual information we (United Kingdom) and Prof. G.X.Li (China). would like to note that some sedimentary We are grateful to all the aforenamed scientists mineral resources (biogenic phosphorites, iron for management of the essential collections of -bearing quartzites, gold-forming black the Paleontological Museum in future. The Joint shales, diaspore bauxite, supposed “coal-and- Project was supported by Dr. Kh.Tsogtbaatar, oil-gas- bearing Sabkha Formation”-salt director of Paleontological Institute, Mongolian domes) could be formed by significant Academy of Science. assistance of bacterial microfossils (Dorjnamjaa et al., 2018, 2019). 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