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Showing 1 to 20 of 50 for “"microfossils"”.
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Inference of ecology from the ontogeny of microfossils
This work comprises three detailed studies of ontogeny and ecology. In the first chapter, four living species of the ostracode genus Cyprideis were studied both morphologically and ecologically to determine whether differences in age at maturity are correlated with heterochrony as expected; …
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Inference of ecology from the ontogeny of microfossils
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1989.
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The Utility of Microfossils in Geoarchaeology: A Case Study from Lake Simcoe, Ontario and Methodological Considerations
… higher fossilization potential than mineralized microfossils like diatoms, although some, notably desmids, were shown to be sensitive to acetolysis. Algal palynomorphs record cultural eutrophication since European settlement at all three sites in a north-south transect (particularly at the …
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The Application of Macro- and Microfossils to Identify Paleoearthquakes in Sumatra, Indonesia and to Characterize Geomorphic and Ecological Succession on a Marsh Platform After Hurricane Isabel in North Carolina, USA
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Exceptional Preservation and Bias in the Fossil Record
… Winneshiek Lagerstätte in northeastern Iowa and microfossils from the Doushantuo Formation of South China, respectively. Chapter two aims at resolving the identity of the Winneshiek vermiform fossils and presents evidence that these structures represent phosphatized bromalites, an ichnologic …
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The Experimental Silicification of Bacillus subtilis
… signs of life found beyond Earth may occur as microfossils in silica deposits. Experiments were conducted on the gram positive bacterium Bacillus subtilis to test the effects of silica concentration, dissolved Fe, and dissolved Al upon silicification processes. Results from initial experiments …
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The Experimental Silicification of Bacillus subtilis
… signs of life found beyond Earth may occur as microfossils in silica deposits. Experiments were conducted on the gram positive bacterium Bacillus subtilis to test the effects of silica concentration, dissolved Fe, and dissolved Al upon silicification processes. Results from initial experiments …
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Contributions to the Proterozoic and Cambrian Evolution of Eukaryotes
… ecosystems. Chapter 4 focuses on Cambrian microfossils that represent the primary producers' cyanobacteria and eukaryotic phytoplankton (acritarchs). Careful investigation of the basal Cambrian Yanjiahe Formation in the Yangtze Gorges area and the Yurtus Formation in the Aksu area revealed …
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ΜΕΛΕΤΗ ΤΩΝ ΜΟΛΑΣΣΙΚΩΝ ΙΖΗΜΑΤΩΝ ΤΟΥ ΣΧΗΜΑΤΙΣΜΟΥ ΤΣΟΤΥΛΙΟΥ ΤΗΣ ΜΕΣΟΕΛΛΗΝΙΚΗΣ ΑΥΛΑΚΑΣ (ΜΙΚΡΟΠΑΛΑΙΟΝΤΟΛΟΓΙΑ-ΣΤΡΩΜΑΤΟΓΡΑΦΙΑ)
… OF THE PLANKTONIC FORAMINIFERA AND OTHER MICROFOSSILS FOUND WITHIN THE MOLASSIC SEDIMENTS, B) A BIOZONATION BASED ON THE STRATIGRAPHIC RANGES OF THE PLANKTONIC FORAMINIFERA IDENTIFIED AND C) A MINERAL AND GRAIN -SIZE ANALYSIS OF THE SEDIMENTS DISCUSSED. THE RESULTS HAVE BEEN USED TO DRAW …
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Constraining the Ediacaran-Cambrian boundary in South China using acanthomorphic acritarchs and Palaeopascichnus fossils
… strata of South China suggest that these microfossils may provide an appropriate biostratigraphic marker for the Ediacaran-Cambrian boundary, because of their wide distribution in chert-phosphorite layers intercalated with carbonates and shales, thus allowing their biostratigraphic …
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Sedimentologic and Stratigraphic Significance of Boulder Layers in the Outer Coastal Plain of Southeastern Virginia
… Formation. The sediments, heavy minerals and microfossils within the boulder layers in addition to boulder lithologies, dimensions and orientations were studied to determine the origin of these layers. These data indicate the boulder layers were separated into two similar yet distinct …
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Organic Carbon Cycling in East China Sea Shelf Sediments: Linkages with Hypoxia
… disturbance. Low-oxygen tolerant foraminiferal microfossils were analyzed in another two sediment cores to study the historical hypoxia events in the Changjiang LDE. Bulk carbon to nitrogen (C/N) ratio and stable isotope ?13C in the surface sediment samples indicated a mixture source of …
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Maceral Variations and Maceral Assemblages within the Upper and Lower Members of the Bakken Formation, Williston Basin, Saskatchewan, Canada.
… or bituminite A) and both the amount or type of microfossils present. A number of differing depositional environments for each organic facies are proposed using the presence or absence and type of microfossils (i.e. algae, acritarchs and spores) within each organic facies (and organic facies …
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Contributions and New Methods in Paleontology: Geochemical, Ultrastructural, and Microstructural Characterization of Archean, Proterozoic, and Phanerozoic Fossils
… over the entire range of geologic time, from microfossils to macrofossils and from the Archean (beginning at 3800 Ma) to the Cenozoic (ending at the recent). These techniques, predominantly used for geochemical, morphological, and ultra-/micro-structural analyses, have unlocked an incredible …
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Palaeontology and biostratigraphy of the Lower Cretaceous Qihulin Formation in eastern Heilongjiang, northeastern China
… the macrofossils (ammonites and bivalves) and microfossils (agglutinated foraminifers and radiolarians) have been studied. The low-diversity ammonite fauna consists of Pseudohaploceras Hyatt, 1900, and Eogaudryceras Spath, 1927, which indicate a Barremian-Aptian age. The bivalve fauna consists …
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Foraminifera from outcrops of the Pierre Shale (Upper Cretaceous) of North Dakota
… of North Dakota based on magafossils.</p> <p>Microfossils are considerably more abundant than megafossils in the Pierre shale of North Dakota. Here, the types of microfossils, known to the writer, include Foraminifera, Radiolaria, sponge spicules and Ostracoda. It was hoped that a study of the …
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Petrographic and petrophysical characterization of the Eagle Ford Shale in La Salle and Gonzales counties, Gulf Coast Region, Texas
… Ford Shale, where both benthonic and planktonic microfossils were identified. The most abundant microorganisms are foraminifera, although echinoderms, bivalves, fish bones, radiolaria, coccoliths and calcispheres are also present. This diversity in microfossils reinforces the cyclic character of …
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Analysis and pattern mapping of organic interfaces by means of seismic geophysical technologies to investigate archaeological palaeolandscapes beneath the Southern North Sea
… remains, dating proxies, pollen, diatoms, microfossils, coleoptera etc. is peat. This research supports the search for peat in submarine environments by interpreting seismic surveys of the sub-sea floor and analysing reflective signals for distinctive organic responses. By means of …
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Palynology of acid-saline lakes of western Australiabiostratigraphy and paleoenvironmental reconstruction
… and quantification of organic-walled microfossils yielded two palynomorph assemblages that reflect a climatic turnover: (1) a wet hinterland (rainforest), freshwater and swampy assemblage found in situ in the basal lignites of LA2-09 (44.58-59.63 meters); and (2) a sclerophyllic and …
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