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Showing 1 to 16 of 16 for “"micrite"”.
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Autecology, Development and Diagenesis of a Phylloid Stromatolitic Blue Green Algal bioherm, Laborcita formation, Sacramento Mountains, New Mexico
… marine cementation and infiltration of micrite and layered pelletal micrite between algal thalli controlled mound development.</p> <p>After deposition of the mound, subaerial diagenesis created an extensive network of interconnected solution voids which transect primary structures. …
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Stratigraphy and depositional environments of the Three Forks Formation (Upper Devonian), Williston Basin, North Dakota
… North Dakota. The Three Forks is composed of micrite and dolomicrite, which may be fcssiliferous and argillaceous. From the study of core samples and detailed petrographic analysis of thin sections, five lithofacies were recognized and their extent determined. These lithofacies are: micrite, …
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Diagenesis of the middle member of the Bakken Formation, Williston Basin, North Dakota
… calcite, dolomite, fossil/fossil fragments, micrite/micritic matrix, porosity (intragranular and fracture), pyrite, quartz silt, and any miscellaneous grains not otherwise taken into account. All cores were analyzed for other potential diagenetic traits such as compaction, soft sediment …
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Depositional Environments of Siliceous Laminites in the Laney Member of the Green River Formation, Sublette County, Wyoming
… association of stromatolites , mud-cracked dolomicrites and ostracodal micrite, (2) fossil occurrences of Knightia (Herring-type fish) and Equisetum (horsetail), Astephus (catfish), Amyzon (sucker ) and (3) presence of dolomite and aragonite.</p> <p>The excellent preservation of these …
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Terminal proterozoic carbonate platform development : stratigraphy and sedimentology of the Kuibis Subgroup (ca. 550-548 Ma), Northern Nama Basin, Namibia.
… may have been produced through aggregation of micrite, precipitated by abiotically or microbially-regulated processes, to form larger, sand-sized particles. As such, the Kuibis platform shares many characteristics in common with older Proterozoic carbonate ramps, but also some features more …
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Lithostratigraphic investigation of a Late Devonian carbonate-evaporite sequence; the Duperow Formation, Williston Basin, North Dakota
… The main diagenetic features observed are micrite enveloping and micritization, calcite cementation, dolomitization, compaction, dissolution, and anhydrite cementation. Only dolomitization and dissolution increase porosity in the rocks of the Duperow. Dolomitization is fabric selective, as …
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The geology and hydrocarbon potential of the Dawson Bay Formation carbonate unit (Middle Devonian), Williston Basin, North Dakota
… includes: color-mottling, dolomitization of micrite to microcrystalline dolomite with penecontemporaneous anhydrite replacement of cryptalgal mudstones and boundstones, cementation by sparry calcite, and vuggy porosity development. Mesogenetic diagenesis includes: formation of mosaic …
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The Carboniferous Courceyan-Chadian) Sedimentary Facies Mosaic of the Keel -Ardagh Area of County Longford, Eire
… belts were moving northwards. Lagoonal (Navan Micrite) deposits were laid down behind a barrier complex now represented by the Upper Mixed Beds.<br/><br/>To seaward of the barrier shallow marine calcareous sediments were deposited on a homoclinal ramp. These are represented in the Keel area by …
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An Avian Botulism Epizootic Affecting a Nesting Site Population of Presbyornis : on a Carbonate Mudflat Shoreline of Eocene Fossil Lake
… skull and sternum) were removed from the micrite matrix to provide the first nearly complete composite skeleton of Middle Eocene <em>Presbyornis</em>. This is the first reported taphonomic map of an avian fossil quarry, the strongest evidence of associated <em>Presbyornis</em> skeletons, …
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Paleogeography and Paleoenvironments of the Lower Unit, Fossil Butte Member, Eocene Green River Formation, Southwestern Wyoming
… by kerogen rich to kerogen poor finely laminated micrites , that consist mainly of calcite and very little dolomite. These carbonates contain well preserved fossil fish, ostracodes, molluscs and the kerogen that was produced mainly by algae. These rocks grade towards the margins into micrites that …
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The petrography and major element geochemistry of the phosphorite nodule deposits on the Agulhas Bank, South Africa
… glauconite and microfossil grains set in a micrite/collophane cement (N III class). Surface to centre phosphatization effects have been observed in some N I nodules. The first conglomeratic variety (C I class) is noted for abundant, often highly irregularly shaped, enclosed N I class …
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MISSISSIPPIAN MUD MOUNDS OF DERBYSHIRE (ENGLAND, UK): FACIES ARCHITECTURE AND BIOTIC EVOLUTION
… microbial-metazoan marine benthic community (automicrite). Mud mounds are the dominant reef type in the Mississippian but have no extant analogue, which hampers the understanding of their growth style, depositional environment, and palaeoecology. The factors influencing mud mound growth and the …
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Lithofacies Determination in the Willesden Green and South Pembina Duvernay Formation: Creation, Characterization, and Correlation
… in the matrix that include clay, TOC and micrite; however, recrystallized carbonate appears to have a large influence when present. Quartz and carbonate silts and carbonate fossil fragments appear to have a much more negligible effect on elastic properties. Unexpectedly the combined effect …
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Stromatolitic Knobs in Storrs Lake, San Salvador, Bahamas: Insights into Organomineralization
<p>Storrs Lake, a hypersaline lake on the east coast of San Salvador Island, Bahamas, contains well-developed microbial mats, some of which have developed calcified structures called microbialites. Many of these microbialites are laminated, and therefore classified as stromatolites. This study …
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Investigations on sedimentology and early diagenesis in shallow-water warm-temperate to tropical miocene carbonates : a case study from Northern Sardinia, Italy
… depositional setting. High-Mg calcite cements (micrite, fibrous and syntaxial inclusion-rich) are early syn-depositional, facies-related (shallow-water), predominant at the platform phase, and marine in origin. Low-Mg calcite cements (bladed, syntaxial inclusionpoor and blocky) are early to late …
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Patterns of Lithology, Structure, Alteration, Trace Elements, Carbonate Mineralogy, and Stable Isotopes around High-Grade Carlin-type Gold Deposits: Turquoise Ridge Deposit, Getchell District, Nevada
… associated with visibly unaltered recrystallized micrite are between 17.6‰ and 19.0‰, well below typical δ18O values associated with unaltered Paleozoic carbonates (22‰ to 28‰). The spatial distribution of δ18O values along an east-west cross-section through the northern portion of the Turquoise …