Journal articles on the topic 'Stromatolites'
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1
Silva, Loreine Hermida da Silva e., Anderson Andrade Cavalcanti Iespa, and Cynthia Moreira Damazio Iespa. "Composição dos estromatólitos estratiformes da lagoa Salgada, Rio de Janeiro, Brasil." Anuário do Instituto de Geociências 31, no. 2 (December 1, 2008): 42–49. http://dx.doi.org/10.11137/2008_2_42-49.
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Lagoa Salgada is situated in the north coast of State of Rio de Janeiro, between the districts of Campos dos Goitacazes and São João da Barra, some 41º00'30" W and 21º54'10"S. In the margins of the lagoon the presence of recent stromatolitic constructions was verified. The stromatolite may be defined as lithifying biosedimentary structure, growing through of sediment blade trapping by the carbonate precipitation as result of microbian organism activity. The aim of this study was to characterize the cyanobacteria assemblage in stratiform stromatolites found on the floor of lagoa Salgada. Within the stratiform stromatolites 21 species of cyanobacteria were found, Microcoleus chthonoplastes (Thuret) Gomont 1892 and Lyngbya aestuarii (Liebman) Gomont 1892 are frequent in these stromatolites. The presence of calcite was observed in the stratiform stromatolites. The filamentous cyanobacteria are responsible for the union and imprisonment of sediment to form the layers in the stromatolites. The skeleton remains of mollusks, foraminifers and ostracod found in the area, work as a source of calcium carbonate and of sediment to structure the stromatolites
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Riding, Robert, Stanley M. Awramik, Barbara M. Winsborough, Karen M. Griffin, and Robert F. Dill. "Bahamian giant stromatolites: microbial composition of surface mats." Geological Magazine 128, no. 3 (May 1991): 227–34. http://dx.doi.org/10.1017/s001675680002207x.
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AbstractSubtidal columnar stromatolites up to 2.5 m high near Lee Stocking Island in the Exuma Cays, Bahamas, have surface mats approximately equally composed of algae and cyanobacteria. The stromatolites are composed of fine–medium oöid and peloid sand. This sediment is supplied to the growing stromatolite surfaces by strong tidal currents which lift grains into suspension and sweep migrating dunes over the columns. The algae include an unidentified filamentous chlorophyte, and numerous diatom species mostly belonging to Mastogloia, Nitzschia and Navicula. The dominant cyanobacteria are two oscillatoriacean species, both probably belonging to Schizothrix. Trapping of sediment is mainly effected by the unidentified chlorophyte which is veneered by epiphytic diatoms. Grains are bound into a mucilaginous mat composed of diatoms and cyanobacteria. Cyanobacteria alone would not be able to trap and bind coarse sediment so effectively in this environment. In being coarse-grained and having a significant eualgal component to their mats, these stromatolites are similar to subtidal columnar stromatolites at Shark Bay, Western Australia. The Lee Stocking stromatolites are physically stressed by high velocity tidal currents and mobile sediment. The Shark Bay stromatolites are stressed by hypersalinity. In both cases stress deters grazers, encrusters and bioeroders. These coarse-grained eualgal stromatolites contrast with micritic and predominantly prokaryotic stromatolites of most Recent marine environments, and are not analogues for most pre-Phanerozoic stromatolites. They appear to be a response to changing stromatolitic mat components in the Cenozoic.
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Douglas, Susanne, Meredith E. Perry, William J. Abbey, Zuki Tanaka, Bin Chen, and Christopher P. McKay. "The structure and chemical layering of Proterozoic stromatolites in the Mojave Desert." International Journal of Astrobiology 14, no. 3 (March 9, 2015): 517–26. http://dx.doi.org/10.1017/s1473550415000026.
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AbstractThe Proterozoic carbonate stromatolites of the Pahrump Group from the Crystal Spring formation exhibit interesting layering patterns. In continuous vertical formations, there are sections of chevron-shaped stromatolites alternating with sections of simple horizontal layering. This apparent cycle of stromatolite formation and lack of formation repeats several times over a vertical distance of at least 30 m at the locality investigated. Small representative samples from each layer were taken and analysed using X-ray diffraction (XRD), X-ray fluorescence (XRF), environmental scanning electron microscopy – energy dispersive X-ray spectrometry, and were optically analysed in thin section. Optical and spectroscopic analyses of stromatolite and of non-stromatolite samples were undertaken with the objective of determining the differences between them. Elemental analysis of samples from within each of the four stromatolite layers and the four intervening layers shows that the two types of layers are chemically and mineralogically distinct. In the layers that contain stromatolites the Ca/Si ratio is high; in layers without stromatolites the Ca/Si ratio is low. In the high Si layers, both K and Al are positively correlated with the presence and levels of Si. This, together with XRD analysis, suggested a high K-feldspar (microcline) content in the non-stromatolitic layers. This variation between these two types of rocks could be due to changes in biological growth rates in an otherwise uniform environment or variations in detrital influx and the resultant impact on biology. The current analysis does not allow us to choose between these two alternatives. A Mars rover would have adequate resolution to image these structures and instrumentation capable of conducting a similar elemental analysis.
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Rakhmanova, А. V. "History of the study of Karelia Paleoproterozoic stromatolites and their display at the Museum of Precambrian Geology, Petrozavodsk." Vestnik of Geosciences 4 (2021): 25–31. http://dx.doi.org/10.19110/geov.2021.4.4.
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The paper deals with the history of stromatolite studies in the Republic of Karelia and the compiling of a stromatolite collection at the Museum of Precambrian Geology, IG, KarRC, RAS, Petrozavodsk. Major stages in the study of Karelia’s Proterozoic stromatolites are presented, changes in the point of view of their origin are assessed and the exposition «Karelia’s and worldwide stromatolites» is described for the first time. Analysis of the history of Karelia’s widespread and accessible stromatolites and a review of the stromatolite collection at the museum are of scientific and educational interest.
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Papineau, Dominic, Jeffrey J. Walker, Stephen J. Mojzsis, and Norman R. Pace. "Composition and Structure of Microbial Communities from Stromatolites of Hamelin Pool in Shark Bay, Western Australia." Applied and Environmental Microbiology 71, no. 8 (August 2005): 4822–32. http://dx.doi.org/10.1128/aem.71.8.4822-4832.2005.
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ABSTRACT Stromatolites, organosedimentary structures formed by microbial activity, are found throughout the geological record and are important markers of biological history. More conspicuous in the past, stromatolites occur today in a few shallow marine environments, including Hamelin Pool in Shark Bay, Western Australia. Hamelin Pool stromatolites often have been considered contemporary analogs to ancient stromatolites, yet little is known about the microbial communities that build them. We used DNA-based molecular phylogenetic methods that do not require cultivation to study the microbial diversity of an irregular stromatolite and of the surface and interior of a domal stromatolite. To identify the constituents of the stromatolite communities, small subunit rRNA genes were amplified by PCR from community genomic DNA with universal primers, cloned, sequenced, and compared to known rRNA genes. The communities were highly diverse and novel. The average sequence identity of Hamelin Pool sequences compared to the >200,000 known rRNA sequences was only ∼92%. Clone libraries were ∼90% bacterial and ∼10% archaeal, and eucaryotic rRNA genes were not detected in the libraries. The most abundant sequences were representative of novel proteobacteria (∼28%), planctomycetes (∼17%), and actinobacteria (∼14%). Sequences representative of cyanobacteria, long considered to dominate these communities, comprised <5% of clones. Approximately 10% of the sequences were most closely related to those of α-proteobacterial anoxygenic phototrophs. These results provide a framework for understanding the kinds of organisms that build contemporary stromatolites, their ecology, and their relevance to stromatolites preserved in the geological record.
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Lambert, M. B. "Stromatolites of the late Archean Back River stratovolcano, Slave structural province, Northwest Territories, Canada." Canadian Journal of Earth Sciences 35, no. 3 (March 1, 1998): 290–301. http://dx.doi.org/10.1139/e97-115.
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Nine stromatolite localities in the Back River volcanic complex occur at the boundary between 2692 Ma felsic dome-flow complexes, marking the latest eruptions of this stratovolcano, and overlying turbiditic sedimentary rocks of the Beechy Lake Group, Yellowknife Supergroup. Stromatolites form lenses isolated within coarse volcanic breccia at margins of felsic dome-flow complexes, and 2 m thick bioherms that extend laterally for hundreds of metres. Thin units contain wavy laminae and open-spaced, linked mounds, which form thin encrustations on breccia blocks, or clusters of mounds with low synoptic relief. Thick successions comprise undulatory, flat laminated dolomite that contains wrinkled wavy laminae, pseudocolumnar forms, and locally elongate, low-relief mounds. These units typically contain millimetre-scale layers of fine volcanic ash at regular intervals, testifying periodic explosive eruptions during deposition of microbial mats. The stromatolites, which are identified by gross morphology and distinctive laminae, are all stratiform types. Carbonate units all occur on the seaward side of the volcanic dome-flow complexes that straddled the shoreline around the volcano. The stromatolites probably represent isolated microbial communities that may have developed around areas of fumarolic (or hydrothermal) activity associated with these domes. Stratigraphy seaward from the domes comprises carbonate-cemented dome-flanking breccia, stromatolitic and oolitic carbonate, pebbly rhyolite volcarenite, carbonaceous mudstones, banded iron formation, and turbidites. Thus the stromatolites mark a local environment where life flourished in an Archean sea that lapped onto active volcanic domes along the shallow flanks of an emergent stratovolcano.
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Brook, George A., A. Cherkinsky, L. Bruce Railsback, Eugene Marais, and Martin H. T. Hipondoka. "14C Dating of Organic Residue and Carbonate from Stromatolites in Etosha Pan, Namibia: 14C Reservoir Effect, Correction of Published Ages, and Evidence of >8-m-Deep Lake During the Late Pleistocene." Radiocarbon 55, no. 3 (2013): 1156–63. http://dx.doi.org/10.1017/s0033822200048062.
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Lacustrine stromatolites are layered accretionary structures formed in shallow water by cyanobacteria. They are a precise indicator of high lake limits and their morphology and structure provide an insight into paleoenvironments of the time. Previous research on lacustrine stromatolites from Etosha Pan in Namibia based on radiocarbon ages of carbonates were close to the limit of the method and did not account for any possible 14C reservoir effect. The ages were used to suggest that the basin was not extensively flooded during the last 40,000 yr. To assess the reservoir effect, the age characteristics of a stromatolite from Poacher's Point were investigated by 14C dating both carbonate and organic residue from samples at different depths in the deposit. The ∼15-cm-diameter stromatolite was separated into 12 zones from the center to the edge and block samples were cut from each zone; the carbonate and residual organic residue were dated separately. The carbonate ages ranged from 34,700 to 24,700 14C yr BP and the organic ages from 15,700 to 2500 14C yr BP. Ages generally increased with increasing distance from the surface of the deposit. We believe that the organic ages are an accurate estimate of the stromatolite's age, while the much older carbonate ages reflect incorporation of old carbon from limestone bedrock and ancient calcrete introduced by stream and spring flow. Excluding the 2 oldest organic ages (15,700 and 13,600 14C yr BP), which may reflect contamination by older organic material washed into the lake during flooding, a linear regression relationship between carbonate and organic ages indicates that the reservoir effect on carbonate ranges up to ∼24,000 14C yr BP but decreases slightly as the true age of the deposit increases. This regression relationship was used to correct 2 finite carbonate ages for stromatolites from Pelican Island obtained in the early 1980s, which together with our new organic age for a stromatolite from Andoni Bay, document a >8-m-deep lake in Etosha Pan during the Late Pleistocene, at and prior to ∼34,000–26,000 cal yr BP. The organic carbon ages from the Poacher's Point stromatolite suggest prolonged lacustrine conditions during the early to middle Holocene (8000–6600 cal yr BP) but not to the extent seen during the Late Pleistocene.
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Hofmann, H. J., and A. Davidson. "Paleoproterozoic stromatolites, Hurwitz Group, Quartzite Lake area, Northwest Territories, Canada." Canadian Journal of Earth Sciences 35, no. 3 (March 1, 1998): 280–89. http://dx.doi.org/10.1139/e97-103.
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Decimetric to metric domal stromatolites with constituent ministromatolites characterize reddish, 13C-enriched dolostones in the Watterson Formation of the Quartzite Lake area west of Hudson Bay. They provide paleontologic support for a correlation with the only other known early Paleoproterozoic stromatolite occurrences in North America: the Kona Formation of Michigan, and the Nash Formation in southern Wyoming. They also are similar to stromatolites in probable coeval Jatulian carbonates in Karelia on the Baltic Shield, and possibly to stromatolites in the Hutuo Group in China.
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Riding, Robert. "Abiogenic, microbial and hybrid authigenic crusts: components of Precambrian stromatolites." Geologia Croatica 61, no. 2-3 (December 25, 2008): 73–103. http://dx.doi.org/10.4154/gc.2008.10.
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Authigenic seafloor carbonate crusts include fenestrate microbialite, thrombolite, and four types here designated Fine-grained Crust, Sparry Crust, Hybrid Sparry Fine-grained Crust, and Sparry Crust plus Coarse Grains. Each of the latter four types includes at least some layered examples that have generally been regarded as stromatolites. Recognition and interpretation of these various deposits assists understanding of stromatolite development. Sparry Crust is common in the Late Archaean-Mesoproterozoic. It includes botryoidal fans and other crystal pseudomorphs, microdigitate stromatolite, dendrite, isopachous laminite, and herringbone calcite. Although differing in primary mineralogy and bedform, these are all characterized by coarse sparry, commonly radial fibrous, fabric and appear light coloured in thin-section. They have commonly been referred to as seafloor cement, although they formed at the open sediment-water interface rather than as void-fills. Two of them in particular, isopachous laminite and microdigitate ‘tufa’, typically form isopachous layers with good vertical inheritance and have been regarded as stromatolites. In contrast to Sparry Crust, Fine-grained Crust has fine-grained (micritic, clotted, peloidal, filamentous) microfabric that appears dark in thin-section, and irregular uneven layering with relatively poor inheritance. Mixed crusts, composed of millimetric alternations of Sparry and Fine-grained crust, are here termed Hybrid Sparry Fine-grained Crust. Sparry Crust with coarse allochthonous grains - here termed Sparry Crust plus Coarse Grains – includes some examples that have been given formal stromatolite names, e.g., Gongylina and Omachtenia. Sparry, Hybrid, and Fine-grained crusts are common components of Precambrian stromatolites. Their relative abundances change through time. Archaean stromatolite fabrics are commonly obscured by recrystallization, but their preserved lamina arrangements suggest that many of them could be composed mainly of Sparry or Hybrid crust. During the Palaeoproterozoic-Mesoproterozoic, Sparry Crust fabrics were common in peritidal stromatolites, whereas Hybrid Crust appears to have dominated large subtidal domes and columns. Fine-grained Crust may not have become generally abundant until the Neoproterozoic, when it commonly formed both stromatolites and thrombolites. Phanerozoic normal marine stromatolites are also typically composed of Fine-grained Crust. Present-day analogues of Sparry Crust fabrics occur in some speleothem, hot spring, and splash-zone marine crusts, and of Fine-grained Crust in lithified microbial mats. Light-dark millimetric alternations of sparry and fine-grained crust that characterize Hybrid Crust have analogues in freshwater stromatolites. Taken together, these comparisons suggest that some Precambrian stromatolites are abiogenic, some microbial, and others are intimate hybrid mixtures of the two, and that - preservation permitting - these varieties can be distinguished using microfabric and lamina criteria.
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Smith, Alan, Andrew Cooper, Saumitra Misra, Vishal Bharuth, Lisa Guastella, and Riaan Botes. "The extant shore platform stromatolite (SPS) facies association: a glimpse into the Archean?" Biogeosciences 15, no. 7 (April 13, 2018): 2189–203. http://dx.doi.org/10.5194/bg-15-2189-2018.
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Abstract. Shore platform stromatolites (SPS) were first noted at Cape Morgan on the south-east African seaboard. Since then they have been found growing discontinuously in rocky peritidal zones along the entire southern African seaboard. They have also been found on the southwest Australian coast, at Giant's Causeway in Northern Ireland, and more recently at Harris on the Scottish Hebridean Atlantic coast. In this paper SPS occurrence and SPS potential as analogues for Precambrian fossil stromatolites, as well as potential stromatolite occurrences in shore platform regions on Mars, are assessed. Sub-horizontal surfaces promote stromatolite development, while tufa develops on cliffs and steep rocky surfaces. Tufa and stromatolites are end members of a spectrum dictated by coastal topography. Extant SPS occur on well indurated shore platforms in high wave energy settings, often around or near headlands. They can be associated with boulder beaches, boulder ridges, storm swash terraces, coastal dunes, and peat bogs. In contrast to other extant stromatolites, SPS are produced primarily by mineral precipitation, although minor trapping and binding stromatolites do occur. From a geological perspective, SPS develop in mildly transgressive siliciclastic settings in various climatic and tidal regimes. We suggest that SPS could be preserved in the geological record as micritic lenses on palaeo-shore platform surfaces. SPS share many features with Precambrian stromatolites and are a valid modern analogue despite the widely different atmospheric and oceanic conditions of the Archean. We suggest that terraces associated with former oceanic or lacustrine flooding surfaces on Mars are potential targets in the search for palaeo-SPS on Mars.
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Villafañe, Patricio Guillermo, Carlos Cónsole-Gonella, Paolo Citton, Ignacio Díaz-Martínez, and Silvina de Valais. "Three-dimensional stromatolites from Maastrichtian–Danian Yacoraite Formation, Argentina: modelling and assessing hydrodynamic controls on growth patterns." Geological Magazine 158, no. 10 (April 29, 2021): 1756–72. http://dx.doi.org/10.1017/s0016756821000315.
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AbstractStromatolites are biogenic sedimentary structures formed by the interplay of biological (microbial composition) and environmental factors (local hydrodynamic conditions, clastic input and/or water chemistry). Well-preserved, three-dimensional (3D) fossil stromatolites are key to assessing the environmental factors controlling their growth and resulting morphology in space and time. Here, we report the detailed analysis of well-exposed, highly informative stromatolite build-ups from a single stratigraphic horizon within the Maastrichtian–Danian Yacoraite Formation (Argentina). This study focuses on the analysis of depositional processes driving intertidal to shallow subtidal stromatolites. Overall depositional architecture, external morphology and internal arrangement (mega, macro, meso and microstructures) of stromatolite build-ups were analysed and combined with 3D photogrammetric models, allowing us to decipher the links between stromatolite structure and tidal dynamics. Results suggest that external morphology and architecture of elongated and parallel clusters grew under the influence of run-off channels. The internal morphology exhibits columnar structures where the space between columns is interpreted as recharge or discharge channels. This work supports the theory that stromatolites can be used as a high-resolution tool in the assessment of water dynamics, and provides a new methodological approach and data for the dynamic reconstruction of intertidal stromatolite systems through the geological record.
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Keim, Carolina N., Hélisson Nascimento dos Santos, Carolina Souza Santiago, Simone Pennafirme, Reiner Neumann, Jürgen Schnellrath, Inayá Lima, Mirian A. C. Crapez, and Marcos Farina. "Microstructure and mineral composition of Holocene stromatolites from Lagoa Vermelha, a hypersaline lagoon in Brazil: Insights into laminae genesis." Journal of Sedimentary Research 90, no. 8 (August 19, 2020): 887–905. http://dx.doi.org/10.2110/jsr.2020.40.
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ABSTRACT Stromatolites are domes, columns, or nearly flat crusts of laminated sedimentary rocks, usually consisting of Ca-Mg carbonates. Stromatolites result from lithification of microbial mats, which are benthic microbial ecosystems where microorganisms arrange themselves in layers according to their physiology. Despite a century of research, the hypothesis of stromatolite genesis by lithification of microbial mats remains controversial, and a convincing explanation for how stromatolites arise from microbial mats is still lacking. In this work, we analyze in detail a stromatolite from Lagoa Vermelha, a coastal hypersaline lagoon in Rio de Janeiro State, Brazil. The stromatolite presents a laminated core and thrombolitic regions at the periphery. Both thrombolitic and laminated facies consist of fine-grained authigenic minerals with minor contributions of bioclasts and quartz grains. X-ray diffraction shows aragonite, high-magnesium calcite (HMC) containing about 17% MgCO3, a very-high-Mg calcite (VHMC) containing 29–46% MgCO3, and small amounts of quartz and pyrite. Scanning electron microscopy of polished samples coupled to energy-dispersive X-ray analysis (EDS) showed that each lamina was composed of 1–4 distinct mineral phases embedded within each other, indicating sequential steps of precipitation of Ca-Mg carbonates under distinct biogeochemical conditions. The coexistence of different phases in a single lamina suggests that several processes contribute to mineral deposition as the incipient stromatolite laminae are left behind by microorganisms from the lower layers of the microbial mat when they grow and/or move upwards.
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Kaya, Mustafa, Belgin Aydin Yildirim, Mustafa Kumral, and Ahmet Sasmaz. "Trace and Rare Earth Element (REE) Geochemistry of Recently Formed Stromatolites at Lake Salda, SW Turkey." Water 15, no. 4 (February 12, 2023): 733. http://dx.doi.org/10.3390/w15040733.
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Stromatolites are the oldest recognized fossil recordings of life on Earth. Therefore, their study of them represents one of the most interesting topic that investigates the physio-chemical environmental conditions (formations and precipitations) at which the stromatolites formed. This work deals with the rare earth elements (REEs) geochemical characteristics and the redox-sensitive trace elements behavior of the stromatolites newly formed in Salda Lake, a closed system alkaline lake surrounded by serpentinite rocks in SW Turkey. The representative stromatolite samples collected from Salda Lake show higher contents of MgO (up to 41.5 wt.%), CO2+OH (up to 56.6 wt.%), and MgO/CaO ratio (up to 42.2 wt.%) referring to the stromatolites had been controlled by microorganisms and deposited in subtidal areas having hydro-magnesite and aragonite mineralogy. The average trace element contents of the stromatolites are 8.4 ppm V, 0.09 ppm Cr, 3.50 ppm Co, 95.6 ppm Ni, 0.73 ppm Cu, 1.55 ppm Rb, 37.6 ppm Sr, 0.59 ppm Y, 17.7 ppm Zr, 3.60 ppm Nb, 21 ppm Ba, 0.05 ppm Hf, 3.5 ppm As, 0.02 ppm Cd, 0.05 ppm U, 0.05 ppm Th, 2.85 ppm Pb, and 6.60 ppm Zn. The Post-Archean Australian Shale (PAAS)-normalized REE patterns of the stromatolites reveal that the heavy REEs (HREEs) are enriched relative to the light REEs (LREEs) with highly negative Y and Ce-anomalies and positive Eu-anomalies. This refers to the stromatolites formed in predominantly oxidizing environmental conditions at partially warm lake waters. In addition, the hydromagnesite composition of the Salda Lake stromatolites indicates that they were precipitated from the waters influenced by Mg-rich meteoric waters fed from the serpentinite rocks around the Lake.
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Sisodia, M. S. "Impact during the proterozoic era possibly inundated the earth with phosphorus." International Journal of Astrobiology 8, no. 3 (May 20, 2009): 187–91. http://dx.doi.org/10.1017/s1473550409004480.
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AbstractThe stromatolites of the Precambrian Aravalli Supergroup outcropping around Udaipur, Rajasthan, India are classified into two distinct lithofacies: the older carbonate stromatolites facies and the younger phosphate-bearing stromatolite facies. Phosphate-bearing stromatolites of the same age have been reported from China, Russia and Australia. The phosphate-bearing stromatolites of Udaipur show fossil cyanobacteria. These cyanobacteria grew luxuriantly in the absence of any competitors and accumulated abnormal amounts of phosphorus from the novo phosphorus-rich environment, eventually forming a workable phosphate deposit owing to their post-mortem alteration. There is a sharp and abrupt contact between the two facies. This sharp contact or diastem underlying the phosphate-bearing stromatolites is of extreme importance as it denotes a stratigraphic hiatus characterizing a period of overall change in the environment. This change could be due to some catastrophic episode. The Earth during its geologic history has been subjected to several such episodes caused by certain high-energy events, such as impacts by extraterrestrial bodies. These impacts caused mass extinctions as occurred at the Permian–Triassic or Cretaceous–Tertiary boundary or the emergence of new flora and fauna as occurred at the Precambrian–Cambrian boundary. It is therefore argued that the diastem noted between carbonate and phosphate-bearing stromatolites is possibly due to an impact that inundated the Earth with phosphorus. Phosphorus is a key constituent of proteins, which are the major repository of chemical energy for metabolism. Its abundance after this event triggered the emergence of new advanced species.
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ANDREWS, S. D., and N. H. TREWIN. "Palaeoenvironmental significance of lacustrine stromatolite forms from the Middle Old Red Sandstone of the Orcadian Basin." Geological Magazine 151, no. 3 (July 19, 2013): 414–29. http://dx.doi.org/10.1017/s0016756813000290.
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AbstractThe form of microbialite accumulations is largely the product of environmental processes and microbial activity. Recent work has largely concentrated on the identification and classification of microbialites with little attention being paid to their environmental significance. This study describes the environmental distribution of the varied stromatolite forms recorded from the Middle Old Red Sandstone sequences of the Orcadian Basin. Comparisons are made with Triassic examples from East Greenland and modern microbialite accumulations. The Middle Old Red Sandstone of Northern Scotland was deposited in a predominantly lacustrine setting. Stromatolites are recorded from both steep basin margin coincident settings and lower gradient settings where the lake margin was distant from the basin margin. In the latter case stromatolite development is largely restricted to transgressive lacustrine sequences, during the deposition of which reduced rates of sedimentation resulted from the migration of sediment input points towards the basin margin. Stromatolite sheets, domal mounds, aligned mounds (and associated runnels), sand-cored stromatolite mounds and reefal stromatolite accumulations have been identified representing the transition from more sheltered to more exposed environments. In basin margin coincident settings stromatolite accumulation is restricted to areas of low sedimentation where microbialites coat boulders and pebbles. A model for the palaeoenvironmental distribution of the stromatolite forms described is proposed and is shown to be applicable to similar examples from the Triassic of East Greenland. It is suggested that this model may be more widely applicable to stromatolitic accumulations in similar lacustrine settings through large portions of the Phanerozoic.
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Bosak, Tanja, Giulio Mariotti, Francis A. MacDonald, J. Taylor Perron, and Sara B. Pruss. "Microbial Sedimentology of Stromatolites in Neoproterozoic Cap Carbonates." Paleontological Society Papers 19 (October 2013): 51–76. http://dx.doi.org/10.1017/s1089332600002680.
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Stromatolite shapes, sizes, and spacings are products of microbial processes and interactions with topography, sedimentation, and flow. Laboratory experiments and studies of modern microbial mats and sediments can help reconstruct processes that shaped some typical stromatolite forms and some atypical microbially influenced sediments from Neoproterozoic cap carbonates. Studies of modern, cohesive microbial mats indicate that microbialaminite facies in the lower Rasthof Formation (Cryogenian) formed in the presence of very low flow and were not deformed by strong waves or currents. Giant wave ripples, corrugated stromatolites, and tube-hosting stromatolites in basal Ediacaran cap carbonates record interactions between microbes, flow, and evolving bedforms. Preferential cementation in and close to the giant ripple crests is attributed to interactions between flow and local topography. These interactions pumped alkaline porewaters into ripple crests and helped nucleate elongated stromatolites. The similar textures of giant wave ripples and elongated, corrugated, and tube-hosting stromatolites suggest growth in the presence of organic-rich, rounded particles and microbial mats, and in flow regimes that permitted mat growth. These hypotheses can be tested by experiments and models that investigate lithification and the macroscopic morphology of microbial mats as a function of the flow regime, preexisting topography, redox-stratification in sediments, and delivery of organic-rich particles. The widespread microbially influenced textures in Cryogenian microbialaminites and basal Ediacaran cap dolostones record a strong reliance of carbonate deposition on the presence of organic nuclei, supporting carbonate accumulation rates comparable to those in modern reefs. Therefore, the unusual macroscopic morphologies of microbially influenced facies in Neoproterozoic cap carbonates may not reflect oceans that were greatly oversaturated with respect to carbonate minerals.
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Ercilla, Oscar. "Origen and evolution of gypsum stromatolites in salars of the Andes highlands, northern Chile." Andean Geology 46, no. 1 (September 28, 2018): 211. http://dx.doi.org/10.5027/andgeov46n1-3029.
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In several salars in the Andes Highlands in Chile, gypsum stromatolites have been described. Stromatolites are structures with organic origin and they are normally formed by carbonates. Field observations achieved in five salars in the Andes of northern Chile have permitted to recognize six stages during the gypsum stromatolites formation, from the growth of the organic mats to their almost disappearance by local erosive agents. The six stages are: 1) formation of the organic mat and start of the mineral structure development, 2) growth of the domes structure by trapping of gases in side of the organic mat, 3) development of the crystal gypsum wall , 4) death of the organic colony and exposition of the stromatolitic domes to the subaerial environment, 5) initial destruction of the dome structure and start of the central cavity filling and 6) final degradation of the structures and formation of the mounds with the gypsum crystals at the top.
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Nehza, Odette, and George R. Dix. "Stratigraphic restriction of stromatolites in a Middle and Upper Ordovician foreland-platform succession (Ottawa Embayment, eastern Ontario)." Canadian Journal of Earth Sciences 49, no. 10 (October 2012): 1177–99. http://dx.doi.org/10.1139/e2012-048.
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Stromatolites are abundant and widely distributed within two narrow stratigraphic intervals in Middle (Darriwilian) and Upper (lower Turinian) Ordovician strata of the Laurentian foreland interior in the Ottawa Embayment, eastern Ontario. These lithostratigraphic markers coincide with rapid, tectonically driven flooding of the foreland interior and may identify an opportunistic microbial response to nutrient loading with shallow (peritidal, subtidal) marine reworking of terrestrial or nutrient-rich coastal systems. The remaining (Chatfieldian–Edenian) foreland-platform succession represents deeper-water deposition in response to elevated subsidence rates along the Laurentian margin. Stromatolites are absent in this higher-energy setting, but microbial calcite is preserved as coccoid-like microencrustations on skeletal debris. Stromatolites of Darriwilian age are dolomitic, occur in the Carillon Formation, and are part of a regional (200+ km) onlap of peritidal sediment during onset of Taconic orogenesis. Stratiform to large (2 m diameter) low-relief domal stromatolites contain rhythmic laminations of inclusion-rich and -poor dolomicrospar grouped by Fe-oxide-stained erosional surfaces. Domal forms also contain thrombolitic microstructure. Patterns of lamination and stable (C, O) isotopes suggest a balance between abiotic and microbial carbonate production, likely influenced by water depth and temperature. Stromatolites of Turinian age are calcitic and form a regional (80+ km) thin (<8 m) subtidal biostromal unit in the lowermost Pamelia Formation. Their occurrence defines an abrupt vertical transition from initial intrabasinal transgressive subtidal phosphatic siliciclastics and carbonates to an interbasinal stratigraphy of peritidal lime mudstone. Arrhythmic laminations of microbial peloid packstone, with possible eukaryote alga moulds, and locally evaporitic spongiostromate microstructure identify salinity and energy as primary depositional controls. The stromatolite–?eukaryotic association is similar to some modern subtidal microstructures and is part of the reef-community diversification in the Ordovician.
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Fuxing, Wang. "Palaeoenvironmental setting of the Kangdian area, southwest China, in Proterozoic Datian–Meidang time." Geological Magazine 124, no. 2 (March 1987): 143–47. http://dx.doi.org/10.1017/s0016756800015958.
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AbstractNumerous acritarchs and stromatolites have been discovered and studied from the Proterozoic Datian Formation of the Kunyang Group and the Meidang Formation of the Dongchuan Group in Sichuan–Yunnan area, southwestern China, and more than 80 oxygen isotope data have been obtained from the sediments. Based on size-range and variation of non-filamentous acritarchs, the development of columnar stromatolites and the 18O/16O values of stromatolitic and nonstromatolitic carbonate rocks, the author proposes, for the first time, a palaeoenvironmental framework of the Kangdian area during Datian–Meidang time.Although the usefulness of Precambrian acritarchs and oxygen isotope values in palaeoenvironmental analysis of a sedimentary basin is just beginning to be understood, it is evident that these data are an important basis for palaeoenvironmental studies.
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Lee, Jeong-Hyun, and Robert Riding. "Keratolite–stromatolite consortia mimic domical and branched columnar stromatolites." Palaeogeography, Palaeoclimatology, Palaeoecology 571 (June 2021): 110288. http://dx.doi.org/10.1016/j.palaeo.2021.110288.
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Cuerno, R., C. Escudero, J. M. García-Ruiz, and M. A. Herrero. "Pattern formation in stromatolites: insights from mathematical modelling." Journal of The Royal Society Interface 9, no. 70 (October 12, 2011): 1051–62. http://dx.doi.org/10.1098/rsif.2011.0516.
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To this day, computer models for stromatolite formation have made substantial use of the Kardar–Parisi–Zhang (KPZ) equation. Oddly enough, these studies yielded mutually exclusive conclusions about the biotic or abiotic origin of such structures. We show in this paper that, at our current state of knowledge, a purely biotic origin for stromatolites can neither be proved nor disproved by means of a KPZ-based model. What can be shown, however, is that whatever their (biotic or abiotic) origin might be, some morphologies found in actual stromatolite structures (e.g. overhangs) cannot be formed as a consequence of a process modelled exclusively in terms of the KPZ equation and acting over sufficiently large times. This suggests the need to search for alternative mathematical approaches to model these structures, some of which are discussed in this paper.
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Casal, Gabriel Andrés, Patricia Vallati, Lucio Manuel Ibiricu, Andrea De Sosa Tomas, Nicolás Foix, José Óscar Alllard, and Rubén Darío Martínez. "Primer registro de estromatolitos en el Maastrichtiano tardío del Grupo Chubut, Cuenca del Golfo San Jorge, Patagonia central, Argentina." Andean Geology 47, no. 1 (January 31, 2020): 162. http://dx.doi.org/10.5027/andgeov47n1-3177.
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The presence of stromatolites from Cretaceous outcrops at the headwaters of the río Chico locality in the Golfo San Jorge Basin is reported for the first time. They are present in the uppermost part of the Lago Colhué Huapi Formation (Coniacian-Maastrichtian) of the Chubut Group. The presence of, up to now, four structures interpreted as stromatolites in this locality are not only important because it is the first record in the basin, but because it contributes to the knowledge of these bioconstructions in continental environments. The stromatolite called E1, which is characterized and discussed in detail, is associated with an abundant and diverse fossil record represented by palynomorphs, fragments of silicified trunks, dinosaur remains and eggshells. The study, integrated mainly with the recorded pollen and spores, is important for paleoenvironmental interpretations of the site and contributes to the paleoecological and paleoclimatic understanding of the most modern stratigraphic interval of the Chubut Group.
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Knoll, Andrew H., Keene Swett, and Elizabeth Burkhardt. "Paleoenvironmental distribution of microfossils and stromatolites in the Upper Proterozoic Backlundtoppen Formation, Spitsbergen." Journal of Paleontology 63, no. 2 (March 1989): 129–45. http://dx.doi.org/10.1017/s002233600001917x.
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The Upper Proterozoic (ca. 700–800 Ma old) Backlundtoppen Formation, northeastern Spitsbergen, preserves an abundant and varied record of ancient microbial life. Five distinctive microfossil assemblages occur in five equally distinct sedimentary settings; differences among the assemblages appear to reflect original ecological heterogeneity, although taphonomic circumstance may contribute to some distinctions. Microfossil assemblages occur in: oncolites, oolites, and pisolites; stratiform stromatolites and associated intraclastic rudites; partially silicified micrites; and siltites interbedded with quartz arenites. Individual assemblages contain one to eight differentiable taxa; a minimum of 17 distinct populations is present in the formation as a whole. Additional microbial community diversity can be inferred from the presence of domal, columnar, pseudocolumnar, and coniform stromatolites, none of which contains microfossils. On the basis of macrostructure, four stromatolite types appear to be present, but only three distinct mat-building communities can be inferred from microstructural features. Eohyella elongata n. sp., a euendolithic cyanobacterium found in silicified pisolites, is described as new.
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Kah, Linda C., Julie K. Bartley, Tracy D. Frank, and Timothy W. Lyons. "Reconstructing sea-level change from the internal architecture of stromatolite reefs: an example from the Mesoproterozoic Sulky Formation, Dismal Lakes Group, arctic Canada." Canadian Journal of Earth Sciences 43, no. 6 (June 1, 2006): 653–69. http://dx.doi.org/10.1139/e06-013.
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The Mesoproterozoic Dismal Lakes Group, arctic Canada, contains a relatively thin, yet regionally extensive stromatolitic reef complex that developed subtidally during a major transgression, shoaled to sea level, and was overlain by intertidal to supratidal carbonate and evaporite strata. The September Lake reef complex exhibits a complex internal architecture that records the interaction between stromatolite growth and changes in accommodation space derived from both higher order (4th- or 5th-order, parasequence-scale) changes in sea level and the variable bathymetry of the sea floor. Reef growth, which was initiated during three sea-level cycles, records progressive marine transgression over depositional lows that were formed during pre-reef subaerial exposure and erosion of the underlying strata. A fourth sea-level cycle, represented by spectacular coniform stromatolites with >10 m of synoptic relief, marks a more dramatic rise in sea level and establishment of the main reef complex. Aggradation and eventual shoaling of the reef complex occurred over an additional six sea-level cycles. Only basinward regions of the September Lake reef complex preserve vertical stacking of reefal packages in response to sea-level fluctuations. In contrast, in the main reef core, sea-level fluctuations resulted in subaerial exposure of the reef top, variable karst development, and the progressive infilling of reef topography by progradational reef elements. Assessment of stromatolite growth patterns reveals the complex nature of the reef architecture and permits the determination of higher order changes in relative sea level that were responsible for reef development.
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Villafañe, Patricio Guillermo, Hugo Corbí, Carlos Cónsole-Gonella, Francisco Javier Ruiz-Sánchez, and Jesús Miguel Soria. "The Messinian stromatolites of the Sierra del Colmenar (Western Mediterranean): facies characterization and sedimentological interpretation." PeerJ 6 (October 16, 2018): e5766. http://dx.doi.org/10.7717/peerj.5766.
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A representative outcrop of the Messinian stromatolites belonging to the Terminal Carbonate Complex unit, from the northern sector of the Bajo Segura basin (Caja de Ahorros del Mediterraneosection, Sierra del Colmenar, SE Spain) has been studied. Here, we present a detailed analysis of the architecture, external morphology, and internal morphology in order to reconstruct the environmental and palaeoecological conditions for their growth. The stromatolites macrostructure consists of a continuously doming type morphology (build up and sheets areas). These developed close to the coast and acted as a palaeogeographic barrier, reducing physical stress, channeling the erosive effect of water and favoring restricted conditions. This stromatolitic macrostructure exhibits variations in its internal morphology, giving rise to seven subfacies, which are a product of the environmental changes experienced during the growth of the microbial mats. Although broadly suggesting a coastal environment, restricted and shallow during formation, the variation in internal morphology (mesostructure and microstructure) is evidence of minor changes in the physical environment that indicate a progressive shallowing.
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Ali, S. Rehan. "Geological Set Up and Mode of Occurrence of Stromatolitic Phosphorites of Gandhra, Panchmahals, Gujarat, India." International Journal of Advance Research and Innovation 2, no. 3 (2014): 33–36. http://dx.doi.org/10.51976/ijari.231406.
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Phosphorite bearing stromatolites of the Champaner Group of Aravalli Super Group have been reported from Panchmahals district, Gujarat. The phosphatic horizon is confined to the Khandia Formation. The stromatolitic phosphorite is traceable over a distance of 2.7 km within crystalline dolomitic limestone around Ranjitpura i.e north of Gandhra and Chalvad villages with their horizontal width of 10 to 30 meters. The Precambrian phosphorite deposits of Panchmahals district, Gujarat show a great variation in their mode of occurrences. They occur as discontinuous lenses and bands, found associated with the dolomitic limestone of the area. On the basis of physico-morphological features, the phosphorite deposits of Panchmahals have been classified into the following varieties, viz., Columnar stromatolitic phosphorite, Laminated stromatolitic phosphorite, Pelletal phosphorite, Nodular phosphorite and Bedded phosphorite.
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Wendt, Jobst. "Solenoporacean Stromatolites." PALAIOS 8, no. 1 (February 1993): 101. http://dx.doi.org/10.2307/3515224.
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Sharma, Mukund, and Santosh K. Pandey. "Stromatolites of the Kaladgi Basin, Karnataka, India: Systematics, biostratigraphy and age implications." Journal of Palaeosciences 61, no. (1-2) (December 31, 2012): 103–21. http://dx.doi.org/10.54991/jop.2012.353.
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Systematics of the stromatolites of the Proterozoic Kaladgi Basin is attempted. The main purpose is to document the diversity and distribution of the various stromatolite forms occurring in the Bagalkot Group of the Kaladgi Supergroup. An assemblage of six taxa is recognized from the Bagalkot Group. The forms Asperia digitata (=Yelma digitata), Ephyaltes edingunnensis, Eucapsiphora leakensis, Kussoidella karalundiensis, Pilbaria deverella and Yandilla meekatharrensis are described. These forms are not recorded from any other Proterozoic Sequence of India of the Palaeoproterozoic age. Similar forms are recorded from Africa, Australia, Canada and China. Asperia digitata, a digitate stromatolite, is known from the Proterozoic Sequence of the Palaeoproterozoic age in other parts of the world. Poorly constrained age of the Bagalkot Group of the Kaladgi Supergroup can be ascertained on the basis of the reported assemblage as Late Palaeoproterozoic to Early Mesoproterozoic (Orosirian-Statherian to Calymmian Period).
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Petryshyn, Victoria A., Frank A. Corsetti, William M. Berelson, Will Beaumont, and Steve P. Lund. "Stromatolite lamination frequency, Walker Lake, Nevada: Implications for stromatolites as biosignatures." Geology 40, no. 6 (June 2012): 499–502. http://dx.doi.org/10.1130/g32675.1.
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Avdonin, V. V., E. A. Zhegallo, and N. E. Sergeeva. "Bacterial mats of the oxide ores in the world ocean." Proceedings of higher educational establishments. Geology and Exploration, no. 4 (August 28, 2017): 45–49. http://dx.doi.org/10.32454/0016-7762-2017-4-45-49.
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Bacterial mats, formed by successively accumulating biofilms, are the main constructive component of the oxide ferromanganese ores on the oceanic floor. The coordinated behavior of the bacterial colonies in the biofilms controlled the growth of the stromatolites and onkolites structures. Biofilms of the stromatolite bacterial mats represent the microbial community, with the thread bacteria forming a poiygonal network that determines a piliar structure of the crusts. Bacterial mats in nodules are festoon-shaped. Biofilms in festoons intensely interact with the environment, assimilating petrogenic components and consuming the sedimentary material.
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Joseph, Rhawn G., Olivier Planchon, N. S. Duxbury, K. Latif, G. J. Kidron, L. Consorti, R. A. Armstrong, C. Gibson, and R. Schild. "Oceans, Lakes, and Stromatolites on Mars." Advances in Astronomy 2020 (October 17, 2020): 1–15. http://dx.doi.org/10.1155/2020/6959532.
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Billions of years ago, the Northern Hemisphere of Mars may have been covered by at least one ocean and thousands of lakes and rivers. These findings, based initially on telescopic observations and images by the Mariner and Viking missions, led investigators to hypothesize that stromatolite fashioning cyanobacteria may have proliferated in the surface waters, and life may have been successfully transferred between Earth and Mars via tons of debris ejected into the space following bolide impact. Studies conducted by NASA’s robotic rovers also indicate that Mars was wet and habitable and may have been inhabited in the ancient past. It has been hypothesized that Mars subsequently lost its magnetic field, oceans, and atmosphere when bolides negatively impacted its geodynamo and that the remnants of the Martian seas began to evaporate and became frozen beneath the surface. As reviewed here, twenty-five investigators have published evidence of Martian sedimentary structures that resemble microbial mats and stromatolites, which may have been constructed billions of years ago on ancient lake shores and in receding bodies of water, although if these formations are abiotic or biotic is unknown. These findings parallel the construction of the first stromatolites on Earth. The evidence reviewed here does not prove but supports the hypothesis that ancient Mars had oceans (as well as lakes) and was habitable and inhabited, and life may have been transferred between Earth and Mars billions of years ago due to powerful solar winds and life-bearing ejecta propelled into the space following the bolide impact.
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Dabkowski, J., J. Andrews, P. Antoine, and A. Marca-Bell. "Stable isotope record of Eemian seasonal temperature from MIS 5e tufa stromatolite; Somme Basin, Northern France." Climate of the Past Discussions 9, no. 2 (March 27, 2013): 1657–74. http://dx.doi.org/10.5194/cpd-9-1657-2013.
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Abstract. In many modern to sub-fossil deposits tufa formations, very well crystallised deposits called stromatolites are preserved. These are often strongly laminated deposits, the laminae linked to seasonal climatic and environmental variations. Where found in fossil tufas such deposits have huge potential as high resolution archives of Pleistocene climate. One of the first investigations of this type has been performed on a 2.5 cm-radius stromatolite from the Eemian sequence of Caours (Somme Basin, Northern France), where precise observations in thin section have been combined with intra-lamina δ18O and δ13C analyses. Independent interpretations of petrographical and geochemical data are strongly coherent and demonstrate a clear seasonal signal. Moreover, as δ18O is temperature dependent, we have quantified likely maximum water temperature variations between summer and winter at Caours. A small mismatch between the δ18O derived temperature values and the typical modern range is observed, which may reflect a real difference between modern and Eemian temperature seasonality. This study supports previous investigations performed on a laminated tufa from central Greece and clearly confirms the potential of tufa stromatolites as records of seasonal climatic information and for the quantification of riverine water temperature variations.
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Abell, P. I., J. McClory, H. E. Hendry, and K. L. Wheatley. "Stratigraphic variations in carbon and oxygen isotopes in the dolostone of the Carswell Formation (Proterozoic) of northern Saskatchewan." Canadian Journal of Earth Sciences 26, no. 11 (November 1, 1989): 2318–26. http://dx.doi.org/10.1139/e89-197.
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Petrographic and stable isotopic analyses of stromatolitic sediments deposited in nearshore environments provides us with some of the best information available on ancient environments. Diamond drill hole CAR 58 penetrated 110 m of sediments in the lowermost part of the Proterozoic (probably Helikian age) Carswell Formation of northern Saskatchewan and gave us such an opportunity. The rocks are mainly dolostone and include, in descending order of abundance, cyanobacterial laminites, stromatolites, dolomicrites, dolorudites, breccias, and oolites. Stromatolites and Cyanobacterial laminites increase in abundance up-section, and deposition is interpreted as having taken place in conditions of increasingly restricted water circulation through time. The carbon isotope ratios vary from about −0.5 to −1.5‰ (Pee Dee Belemnite (PDB)) in the section except near the base where they assume values near −2.5‰. The oxygen isotope ratios (vs. PDB) increase from about −9.3‰ at the base to −7‰ at the top, with anomolously high values, more positive than −7‰, at two positions in the sequence. Original depositional structures and textures are still visible in most of the rocks, but gypsum has been replaced by dolomite, there has been some silicification, and original features have been obliterated by dolomite rhombs in a few samples. The upward trend to less-negative values of the oxygen isotope ratios is interpreted in terms of changing depositional environment involving a deepening but more protected basin, with increased evaporational concentration of the heavier isotope. Scatter diagrams of carbon and oxygen isotope ratios place the Carswell Formation dolomites close to the mainstream of other Proterozoic stromatolites but indicating some evaporative alterations during deposition.
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Sharma, Mukund. "Stromatolites studies in India: An overview." Journal of Palaeosciences 57, no. (1-3) (December 31, 2008): 63–67. http://dx.doi.org/10.54991/jop.2008.228.
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Indian subcontinent with extensive Archaean and Proterozoic sedimentary successions has number of stromatolites occurrences which offers avenues of stromatolites studies. The present paper traces the efforts, strengths and gaps in stromatolites studies in India and summarizes significant Indian contributions made in the past in the country and briefly mentions the global advancements made in this field. The overview covers the period of active research from 1908-2005.
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Suosaari, Erica P., R. Pamela Reid, Amanda M. Oehlert, Phillip E. Playford, Carl K. Steffensen, Miriam S. Andres, Gregory V. Suosaari, Gary R. Milano, and Gregor P. Eberli. "Stromatolite Provinces of Hamelin Pool: Physiographic Controls On Stromatolites and Associated Lithofacies." Journal of Sedimentary Research 89, no. 3 (March 21, 2019): 207–26. http://dx.doi.org/10.2110/jsr.2019.8.
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Raaben, M. E. "Dimensional parameters of columnar stromatolites as a result of stromatolite ecosystem evolution." Stratigraphy and Geological Correlation 14, no. 2 (March 2006): 150–63. http://dx.doi.org/10.1134/s0869593806020031.
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Sackett, William M. "Microbial mats: Stromatolites." Organic Geochemistry 8, no. 2 (January 1985): 193–94. http://dx.doi.org/10.1016/0146-6380(85)90039-7.
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Awramik, Stanley M. "Respect for stromatolites." Nature 441, no. 7094 (June 2006): 700–701. http://dx.doi.org/10.1038/441700a.
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Reyes, Kristina, Nicolas I. Gonzalez, Joshua Stewart, Frank Ospino, Dickie Nguyen, David T. Cho, Nahal Ghahremani, John R. Spear, and Hope A. Johnson. "Surface Orientation Affects the Direction of Cone Growth by Leptolyngbya sp. Strain C1, a Likely Architect of Coniform Structures Octopus Spring (Yellowstone National Park)." Applied and Environmental Microbiology 79, no. 4 (December 14, 2012): 1302–8. http://dx.doi.org/10.1128/aem.03008-12.
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ABSTRACTLaminated, microbially produced stromatolites within the rock record provide some of the earliest evidence for life on Earth. The chemical, physical, and biological factors that lead to the initiation of these organosedimentary structures and shape their morphology are unclear. Modern coniform structures with morphological features similar to stromatolites are found on the surface of cyanobacterial/microbial mats. They display a vertical element of growth, can have lamination, can be lithified, and observably grow with time. To begin to understand the microbial processes and interactions required for cone formation, we determined the phylogenetic composition of the microbial community of a coniform structure from a cyanobacterial mat at Octopus Spring, Yellowstone National Park, and reconstituted coniform structuresin vitro. The 16S rRNA clone library from the coniform structure was dominated byLeptolyngbyasp. Other cyanobacteria and heterotrophic bacteria were present in much lower abundance. The sameLeptolyngbyasp. identified in the clone library was also enriched in the laboratory and could produce conesin vitro. When coniform structures were cultivated in the laboratory, the initial incubation conditions were found to influence coniform morphology. In addition, both the angle of illumination and the orientation of the surface affected the angle of cone formation demonstrating how external factors can influence coniform, and likely, stromatolite morphology.
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Moore, LS. "Water chemistry of the coastal saline lakes of the Clifton-Preston Lakeland system, south-western Australia, and its influence on stromatolite formation." Marine and Freshwater Research 38, no. 5 (1987): 647. http://dx.doi.org/10.1071/mf9870647.
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The water chemistry of Lake Clifton, the adjacent lakes and the regional ground water was investigated to aid in the elucidation of the factors responsible for the restriction of living stromatolites to Lake Clifton. The ionic composition of water in the lakes is proportionally similar to sea water, but the ground water is enriched in calcium and bicarbonate and is of lower salinity (1-2 g I-1). The salinities of the lakes ranged from 7 to 369 g l-1 during 1984 but, in contrast to the other lakes, Clifton remained less saline than sea water throughout the year. Ground waters from an unconfined aquifer on the eastern shore made a large contribution to the annual lake water budget of Lake Clifton, maintaining lake water salinity at less than 35 g l-1 and modifying the chemical composition of the sediment-water interface where stromatolites form. Living, lithified stromatolites occur along the eastern shore of Lake Clifton. They are formed by a benthic microbial community rich in Scytonema. The Stromatolites co-exist with an abundant metazoan fauna, but do not appear to be limited by grazing. Clearly defined zones of ground-water intrusion were found along the eastern foreshore and areas of differential ground-water discharge were associated with morphologically distinctive stromatolites. Occurrence of stromatolites and regions of ground-water discharge in Lake Clifton are consistently associated. It is suggested that the intruding ground waters in Lake Clifton provide a chemical environment conducive to the formation of calcified stromatolites.
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Hillaire-Marcel, Claude, Odette Carro, and Joel Casanova. "14C and Th/U Dating of Pleistocene and Holocene Stromatolites from East African Paleolakes." Quaternary Research 25, no. 3 (May 1986): 312–239. http://dx.doi.org/10.1016/0033-5894(86)90004-9.
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During recent humid episodes, stromatolites were built along paleolake margins, some 60 m above the modern water level of Lakes Natron and Magadi (southern Gregory Rift Valley). Three generations of stromatolites are observed, the more recent ones frequently covering pebbles and boulders eroded from the older ones. The youngest one yielded 14C ages ranging from approximately 12,000 to 10,000 yr B.P. Their δ13C values (≥2.6%) suggest isotopic equilibrium between the paleolake total inorganic dissolved carbon and the atmospheric CO2, thereby lending credence to the reliability of the 14C. An initial 230Th/232Th ratio in the detrital component was determined by Th/U measurements on the 14C dated stromatolites. Using this value a 230Th/234U chronology for the older stromatolites was calculated. Ages of ≥240,000 and 135,000 ± 10,000 yr were obtained for the first and second generations, respectively. A humid episode apparently characterized eastern Africa during each glacial-interglacial transition. 18O and 13C measurements on stromatolites, when compared to values on modern waters and carbonates, provide paleohydrological information. Long residence time of the paleolake waters and less seasonally contrasted regimes are inferred.
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Havemann, Stephanie A., and Jamie S. Foster. "Comparative Characterization of the Microbial Diversities of an Artificial Microbialite Model and a Natural Stromatolite." Applied and Environmental Microbiology 74, no. 23 (October 3, 2008): 7410–21. http://dx.doi.org/10.1128/aem.01710-08.
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ABSTRACT Microbialites are organosedimentary structures that result from the trapping, binding, and lithification of sediments by microbial mat communities. In this study we developed a model artificial microbialite system derived from natural stromatolites, a type of microbialite, collected from Exuma Sound, Bahamas. We demonstrated that the morphology of the artificial microbialite was consistent with that of the natural system in that there was a multilayer community with a pronounced biofilm on the surface, a concentrated layer of filamentous cyanobacteria in the top 5 mm, and a lithified layer of fused oolitic sand grains in the subsurface. The fused grain layer was comprised predominantly of the calcium carbonate polymorph aragonite, which corresponded to the composition of the Bahamian stromatolites. The microbial diversity of the artificial microbialites and that of natural stromatolites were also compared using automated ribosomal intergenic spacer analysis (ARISA) and 16S rRNA gene sequencing. The ARISA profiling indicated that the Shannon indices of the two communities were comparable and that the overall diversity was not significantly lower in the artificial microbialite model. Bacterial clone libraries generated from each of the three artificial microbialite layers and natural stromatolites indicated that the cyanobacterial and crust layers most closely resembled the ecotypes detected in the natural stromatolites and were dominated by Proteobacteria and Cyanobacteria. We propose that such model artificial microbialites can serve as experimental analogues for natural stromatolites.
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Hofmann, H. J., and J. P. Grotzinger. "Shelf-facies microbiotas from the Odjick and Rocknest formations (Epworth Group; 1.89 Ga), northwestern Canada." Canadian Journal of Earth Sciences 22, no. 12 (December 1, 1985): 1781–92. http://dx.doi.org/10.1139/e85-189.
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Moderately well preserved microfossils are reported from two formations of the Epworth Group in the Wopmay Orogen. An assemblage in a stromatolitic unit in the uppermost part of the Odjick Formation contains the microfossils Huroniospora spp., Gunflintia sp., and Frutexites sp. This assemblage, which is remarkable for its preservation in a carbonate matrix, is similar to one found in a stromatolitic chert facies in the Gunflint Iron Formation of Ontario. Taxa in four members of the overlying Rocknest Formation are preserved in cherty dolomites of inner-shelf shallowing-upward cycles capped by small digitate stromatolites. These assemblages comprise the spheroidal taxa Huroniospora spp., Melasmatosphaera magna, Sphaerophycus sp., and Palaeoanacystis sp., the filamentous taxa Archaeotrichion sp., Eomycetopsis sp., Siphonophycus sp., Brevitrichoides sp., Biocatenoides incrustata, Gunflintia? sp., and Archaeonema sp., the acritarch Eomicrhystridium sp., and rare specimens of two unidentified and problematic taxa.
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Carvalho, Carla, Maria Isabela N. Oliveira, Kita Macario, Renato B. Guimarães, Carolina N. Keim, Elisamara Sabadini-Santos, and Mirian A. C. Crapez. "Stromatolite Growth in Lagoa Vermelha, Southeastern Coast of Brazil: Evidence of Environmental Changes." Radiocarbon 60, no. 2 (November 27, 2017): 383–93. http://dx.doi.org/10.1017/rdc.2017.126.
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AbstractAmong the oldest remains of living beings to have inhabited the Earth’s surface, there are the stromatolites—laminated sedimentary rocks associated with lithified mats of layered phototrophic microbial communities—which grow in specific environmental conditions. In the present work, we study a recent carbonatic stromatolite from Lagoa Vermelha (Rio de Janeiro, Brazil), a shallow coastal hypersaline lagoon. X-ray diffraction was associated to a depth chronological model defining three different sections based on changes in mineral composition of the stromatolite with increased dolomite content. Although a mean growth rate of 0.19±0.03 mm/yr is observed, the model discloses decreasing growth rates among the sections. Since dolomite formation can be related to high availability of Mg+2, confirmed by an expressive presence of (Ca, Mg)CO3, the lower growth rates were associated to a more arid environment, until approximately 1440 cal AD, with higher temperatures and consequently promoting water evaporation and salinity enhancement.
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P Burns, Brendan, and Brett A Neilan. "The living rocks of Shark Bay." Microbiology Australia 25, no. 1 (2004): 18. http://dx.doi.org/10.1071/ma04118.
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Stromatolites have been present on Earth, at various levels of distribution and diversity, for more than 3 billion years. Stromatolites are sedimentary structures produced by the sediment-trapping, binding and/or precipitation activity of resident microbial communities, in particular cyanobacteria.
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Goh, Falicia, Stefan Leuko, Michelle A. Allen, John P. Bowman, Masahiro Kamekura, Brett A. Neilan, and Brendan P. Burns. "Halococcus hamelinensis sp. nov., a novel halophilic archaeon isolated from stromatolites in Shark Bay, Australia." International Journal of Systematic and Evolutionary Microbiology 56, no. 6 (June 1, 2006): 1323–29. http://dx.doi.org/10.1099/ijs.0.64180-0.
Full textAbstract:
Several halophilic archaea belonging to the genus Halococcus were isolated from stromatolites from Hamelin Pool, Shark Bay, Western Australia, collected during field trips in 1996 and 2002. This is the first incidence of halophilic archaea being isolated from this environment. Stromatolites are biosedimentary structures that have been formed throughout the earth's evolutionary history and have been preserved in the geological record for over 3 billion years. The stromatolites from Hamelin Pool, Western Australia, are the only known example of extant stromatolites forming in hypersaline coastal environments. Based on their 16S rRNA gene sequences and morphology, the isolates belong to the genus Halococcus. Strain 100NA1, isolated from stromatolites collected in 2002, was closely related to strain 100A6T that was isolated from the stromatolites collected in 1996, with a DNA–DNA hybridization value of 94±8 %. DNA–DNA hybridization values of strain 100A6T with Halococcus morrhuae NRC 16008 and Halococcus saccharolyticus ATCC 49257T were 17±6 and 11±7 %, respectively. The DNA G+C content of strain 100A6T was 60.5 mol% (T m). The main polar lipid was S-DGA-1, a sulphated glycolipid that has been detected in all strains of the genus Halococcus. Whole-cell protein profiles, enzyme composition and utilization of various carbon sources were distinct from those of all previously characterized Halococcus species. The recognition of this strain as representing a novel species within the genus Halococcus is justified, and the name Halococcus hamelinensis sp. nov. is proposed. The type strain is 100A6T (=JCM 12892T=ACM 5227T).
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Patranabis-Deb, Sarbani, and Asru K. Chaudhuri. "Sequence evolution in the eastern Chhattisgarh Basin: constraints on correlation and stratigraphic analysis." Journal of Palaeosciences 57, no. (1-3) (December 31, 2008): 15–32. http://dx.doi.org/10.54991/jop.2008.225.
Full textAbstract:
The Proterozoic succession in the eastern part of the Mesoproterozoic Chhattisgarh Basin comprises two unconformity-bounded sequences. Sequence I represents the Chhattisgarh Supergroup of earlier workers. It overlies rocks of the basement complex with a profound unconformity. Sequence II unconformably overlies Sequnce I, and represents the closing phase of basin evolution during the early Neoproterozoic time. It is unconformably overlain by rocks of the Gondwana Supergroup.
The Lohardi and Gomarda formations at the lower part of the Chandarpur Group of Sequence I comprise an immature succession of conglomerate, sandstone and shale deposited in fan-delta - pro-delta environments, marked by rapid facies changes, variable rates of sediment influx, and uneven rates of subsidence and creation of accommodation space. The Kansapathar Sandstone in the upper part of the Chandarpur Group, by contrast, comprises a sheet of mature arenite deposited in a macrotidal shelf. The immature assemblage is best developed in the eastern part of the basin, and rapidly thins out towards west, where the Kansapathar arenite directly overlies the basement. The Raipur Group provides an excellent example of cyclic sedimentation of red shale and limestone. It comprises three shale-dominated intervals and two carbonate-dominated intervals, organized into multiple shallowing-up cycles. The lower carbonate succession, the Sarangarh Limestone, developed as a shallow water un-rimmed platform and evolved into a deep water ramp, with an extensive thin sheet of black limestone facies. Stromatolites are conspicuously absent in the Sarangarh Limestone. Small stromatolite bioherms appear in the Gunderdehi Shale which overlies the ramp succession, and abundant growth of stromatolite is noted in the upper carbonate succession which evolved as a rimmed platform. A thick ignimbrite horizon in the Churtela Shale attests to major felsic volcanism and termination of the Sequence at ~1000 Ma.
The Kansapathar Sandstone, the black limestone facies of the Sarangarh Limestone, and the Gunderdehi Shale embedded with small stromatolite bioherms can be used as key marker horizons to overcome the problem of intrabasinal correlation. The marker horizons can be traced from the western part to the eastern part of the basin. The stromatolites in the Gunderdehi Shale and in the Saradih Limestone further provide a biostratigraphic frame, subject to detailed morphologic and microstructural analysis, for possible chronostratigraphic classification.
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Álvaro, J. Javier, Emmanuelle Vennin, and Daniel Vizcaïno. "Depositional controls on Early Cambrian microbial carbonates from the Montagne Noire, southern France." Transactions of the Royal Society of Edinburgh: Earth Sciences 89, no. 3 (1998): 135–43. http://dx.doi.org/10.1017/s0263593300007082.
Full textAbstract:
AbstractLower Cambrian shallow-water carbonates enclosing microbial structures are documented for the first time from the upper Lastours Member of the Montagne Noire (southern France). Microbial organisms constructed self-supported boundstones resulting in the formation of exclusively microbial-accreted buildups, which exhibit three main types of non-skeletal microbialites: planar stratiform stromatolites, dome-shaped stromatolites and nonlaminated (thrombolitic) biostromes. In addition, thrombolitic boundstones display four distinct microbial microstructures: clotted andRenalcis-like forms, branching bushy forms, clusters of unbranching straight filaments and crustose forms.The upper member of the Lastours Formation records an upward transition from a shalydominant open shelf to a protected shelf environment bounded by a surface representing a major subaerial exposure. Initially, at the inception of the highstand systems tract, flat stratiform stromatolites formed on open sea subtidal shaly substrates, while stacked domal stromatolites developed in peritidal areas which record subaerial exposure. In contrast, prograding shoal barriers of the transgressive systems tract favoured the establishment of thrombolitic boundstones in protected (back-shoal) environments.
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Baumgartner, Raphael J., Martin J. Van Kranendonk, David Wacey, Marco L. Fiorentini, Martin Saunders, Stefano Caruso, Anais Pages, Martin Homann, and Paul Guagliardo. "Nano−porous pyrite and organic matter in 3.5-billion-year-old stromatolites record primordial life." Geology 47, no. 11 (September 25, 2019): 1039–43. http://dx.doi.org/10.1130/g46365.1.
Full textAbstract:
Abstract Stromatolites of the ∼3.5 billion-year-old Dresser Formation (Pilbara Craton, Western Australia) are considered to be some of Earth’s earliest convincing evidence of life. However, uniquely biogenic interpretations based on surface outcrops are precluded by weathering, which has altered primary mineralogy and inhibited the preservation of microbial remains. Here, we report on exceptionally preserved, strongly sulfidized stromatolites obtained by diamond drilling from below the weathering profile. These stromatolites lie within undeformed hydrothermal-sedimentary strata and show textural features that are indicative of biogenic origins, including upward-broadening and/or upward-branching digitate forms, wavy to wrinkly laminae, and finely laminated columns that show a thickening of laminae over flexure crests. High-resolution textural, mineralogical, and chemical analysis reveals that the stromatolites are dominated by petrographically earliest, nano-porous pyrite that contains thermally mature, N-bearing organic matter (OM). This nano-porous pyrite is consistent with a formation via sulfidization of an originally OM-dominated matrix. Evidence for its relationship with microbial communities are entombed OM strands and filaments, whose microtexture and chemistry are consistent with an origin as mineralized biofilm remains, and carbon isotope data of extracted OM (δ13COM = −29.6‰ ± 0.3‰ VPDB [Vienna Peedee belemnite]), which lie within the range of biological matter. Collectively, our findings provide exceptional evidence for the biogenicity of some of Earth’s oldest stromatolites through preservation of OM, including microbial remains, by sulfidization.
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Pratt, Brian R., and Robert Riding. "Calcareous Algae and Stromatolites." PALAIOS 8, no. 1 (February 1993): 121. http://dx.doi.org/10.2307/3515226.
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