Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 10 of 10 for “"Rhythmites"”.
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Investigating potential climatic cycles in glacially-influenced rhythmites of the upper Gowganda Formation using geochemical, sedimentological and spectral analyses
… contains glacially-induced, varve-like rhythmites composed of turbiditic micro-laminae that potentially preserve a detailed record of climatic conditions during the Paleoproterozoic Era. A sedimentological analysis of upper Gowganda Formation deposits enabled identification of eight …
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Jurassic limestone-marl sequences in northern spain: detecting diagenetic signals using rare earth and trace elements
… depositional signal in these limestone-marl rhythmites. Rare earth and trace element geochemistry is an overlooked method to distinguish the presence of a primary signal from a diagenetic one. The main objective of this study was to test the validity of using rare earth and trace elements as …
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Cyclically-Forced Hyperpycnites of the Ancient Colorado River Proximal Prodelta
… of 12 cm. Sedimentological analysis of the rhythmites reveals the couplets are laterally persistent with gradational to sharp, flat contacts, parallel, wavy, and ripple cross-lamination, and localized internal scours. Notably, grain size analysis performed with laser diffraction techniques …
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Depositional Environments and Sequence Stratigraphy of Upper Mississippian Strata in the Central Appalachian Basin
… deposits within several sequences contain tidal rhythmites. The prodeltaic Pride Shale member (Bluestone Formation) preserves a hierarchy of submillimeter-to meter-scale cycles that reflect a spectrum of tidal periodicities. The abbreviated character of these microlaminated rhythmites is …
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Tidal sedimentation in the mid-Pennsylvanian Breathitt Group, eastern Kentucky
… months of deposition. Accumulation rates for the rhythmites typically ranged from 1 to 7 cm per day, but reached rates of over 30 cm per day where the Magoffin Member is thickest and the most proximal deltaic facies are preserved. Tidal cyclicity was also studied within the Betsie Shale and …
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Evolution of early Proterozoic passive-margin carbonate platform, Rocknest Formation, Wopmay Orogen, N.W.T., Canada
… and inner-shelf facies. Slope facies are rhythmites, megabreccias and rhythmite breccias. Outershelf faciea include stromatolitic reefal boundstone and backreef ooid/intraclast grainstore. Shoal-complex facies are shallowing-upward cycles of tufa, cryptalgalaminite, laminated …
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Investigating laminated sediments of the Al-Azraq basin, Jordan and the implications for paleoenvironmental variability
… flux. The data demonstrate visible laminated rhythmites. XRF results identify alternating laminae of Ca and Si, SEM scans identify seasonal diatoms and EDS demonstrates an encrusting evaporite matrix. Results reveal variability in paleoenvironment with differing sedimentation above and below …
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Sedimentology and Stratigraphy of Glacial Lake Souris, North Dakota: effects of a glacial-lake outburst
… comprised of diamicton overlain by silt and clay rhythmites. Quiet-water lake sedimentation was abruptly halted by coarse-grained outburst sedimentation.</p> <p>Based on surficial mapping, subsurface sample collection, and textural analyses, the outburst sediments have been grouped into three …
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Chemostratigraphy of the Uppermost Cambrian Below the Ordovician GSSP
… gray to black shale and thin ribbon limestone rhythmites, with few fossils. The samples are micritic limestone, dolomitic limestone, and dolostone. They were determined to be in primary to near-primary condition based on multiple screening tests. Cathodoluminescence screening reveals dull to …
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High Resolution Facies & Architectural Analysis of a Tributive, Basal Terrace of a Ferron Compound Incised Valley
The Ferron Sandstone Member of the Cretaceous Mancos Shale is composed of three fluvio-deltaic wedges deposited during the Turonian age along the western margin of the Cretaceous Seaway. The Notom Delta, southernmost of the three complexes, is spectacularly exposed in the washes, road cuts, and …