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 19 of 19 for “"Early Paleozoic"”.
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Petrography and geochemistry of Cambrian-Ordovician marine cements: Implications for Early Paleozoic cementation processes and seawater chemistry
… Cambrian and Ordovician marine environments. Early marine cements which have not recrystallized provide information on coeval seawater chemistry. Marine radiaxial cements from the Cow Head Group and syntaxial cements from both units display mottled luminescence and Fe, Mn, Sr, Mg, stable …
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Structural framework of the Fries fault zone south of Riner, Virginia
… gneiss over deformed Late Proterozoic(?)—Early Paleozoic rocks of the western Blue Ridge province. This work presents an analysis of the field relationships and finite strain patterns within the fault zone, and further relates these features to an interpretation of its structural …
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New Constraints On the Age and Magnitude of Reactivation of the Camden Fault, South Carolina
… is interpreted to separate the Neoproterozoic-Early Paleozoic basement (Richtex Formation of Carolina terrane) on the northwestern side from the Modoc shear zone (MSZ) on the southeast side (sheared rocks of low-grade Richtex Formation and high-grade Mylonitic orthogneiss, Dreher Shoals …
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Geochemical and petrologic study of the Fries-Rockfish Valley Fault near Roanoke, Virginia
… of Laurentia during collisional events in the Paleozoic. This allochthonous basement is composed of Middle Proterozoic continental crust, Late Proterozoic intrusives, and Late Proterozoic-early Paleozoic metasediments and metavolcanics. Two distinct terranes within the Blue Ridge are separated …
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Ultrahigh-resolution paragenesis of the Cambrian-age Mt. Simon Sandstone at a burial depth of 1.8-2.1 km, Illinois basin, USA
… capture and storage (CCS) strategies within early Paleozoic strata of the Illinois Basin. Petrographic analyses of the host quartz arenite Mt. Simon Sandstone lithologies, coupled with wireline log data and formation on Sr-isotope water geochemistry, have permitted the construction and …
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Receiver function study in northeast Tibet and adjacent boundaries
… evidence of a remnant subduction zone from the Early Paleozoic oceanic lithosphere beneath the North China Craton. The Lithosphere-Asthenosphere boundary (LAB) for the western part of the study region is consistent with previous surface wave studies which found a lithospheric thickness of …
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The structural and stratigraphic relationships in the Paleozoic rocks of eastern North Dakota
… and areal extent of the commonly defined Paleozoic rock units in eastern North Dakota has been determined by a study of mechanical well logs. Isopachous wops of these units reveal several positive areas which persisted and influenced sedimentation and unit thickness throughout most of the …
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Paleoecology and Taphonomy of Ediacaran macrofossils from the Khatyspyt Formation, Olenek Uplift, Siberia
… and macroalgae, which had existed since the early Proterozoic, but started to diversify morphologically and ecologically during this geological period. Nevertheless, paleontologists have been studying Ediacaran fossils for more than a century, the key questions about these fossils remain …
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Sedimentology, Stratigraphic Evolution and Provenance of the Cambrian – Lower Ordovician Potsdam Group in the Ottawa Embayment and Quebec Basin
… geologic and tectonic history of Early Paleozoic Laurentia. Nevertheless, in spite of 178 years of study the Potsdam in the Ottawa Embayment and Quebec Basin remains poorly understood. Also poorly understood is how the Potsdam relates with coeval strata regionally. In this work six …
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The tectonic evolution of the Altavista area, Southwest Virginia Piedmont
… the north of Altavista are Late Precambrian to Early Paleozoic in age and correlated to many other areas in the Central and Southern Applalchians. At Altavista the two stratigraphies merge and are correlatable. The Bowens Creek Fault, which bounds the west side of the Smith River Allochthon, …
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Die Erforschungsgeschichte der Eifel-Geologie : 200 Jahre ein klassisches Gebiet geologischer Forschung
… of a regionally confined area (Eifel), from early to modern geoscientific exploration. Concentrating on the most significant classical facts, this work focuses on the beginnings of Eifel exploration. The reader will gain an insight into the discoveries that led to the modern understanding of …
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Biogeochemical and phylogenetic signals of Proterozoic and Phanerozoic microbial metabolisms
… via HGT during the late Neoproterozoic into the early Paleozoic. These results also show that, following these HGT events, recipient terrestrial bacterial clades diversified ∼400-500 Ma, consistent with established timescales of arthropod and plant terrestrialization. Divergence time estimates …
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Bedrock geology of the seacoast region of New Hampshire, United States
… a continuum from the late Silurian through early Paleozoic suggests that folding, magmatic intrusion(s), and ductile followed by brittle faulting affected the seacoast. In this model, after juxtaposition, simultaneous folding of the MG and RC was followed by northeast-trending, right lateral …
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Biogeochemical and phylogenetic signals of Proterozoic and Phanerozoic microbial metabolisms
… via HGT during the late Neoproterozoic into the early Paleozoic. These results also show that, following these HGT events, recipient terrestrial bacterial clades diversified ~400-500 Ma, consistent with established timescales of arthropod and plant terrestrialization. Divergence time estimates …
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An Integrated Geophysical Study of the Central Appalachians of Western Virginia and Eastern West Virginia
… events affecting the Appalachians since the early Paleozoic. The combination of the results of new methods of seismic and potential fields processing with deep well and geologic information allowed the lateral continuity of two major structures in the central Appalachians to be examined. The …
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Petrology of Metadiabase Intrusions in the White Rock Quadrangle, Western North Carolina
… zones of the greenschist facies during the early or middle Paleozoic. The degree of metamorphic alteration varies both from one body to another and within an individual body. However, there does not appear to be any regular pattern of gradation within a body.</p> <p>The primary factors …
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Towards a model of the Cenozoic tectonic development of New Zealand
… plate boundary formed during the early Miocene, about 23 My B.P. (2) A continental rift system developed through western New Zealand during the Paleogene. (3) Northeast of the Alpine Fault the relative plate motion was expressed as a combination of brittle and ductile shearing that …
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Numerical Modeling as a Means to Enhance Genetic Sedimentary Basin Interpretation : A Case Study of the Southern Cantabrian Basin (NW Spain)
… Subsidence rates were obtained for the complete Paleozoic basin fill. These data cover the development of the basin from an early Paleozoic extensional to a late Paleozoic compressional setting that resulted in the creation of the Variscan Orogen. Due to the proximal position of the transects, …
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Stratigraphy, Sedimentology, and Ichnology of the Middle Cambrian to Lower Ordovician Deposits in Subsurface Western Canada
… and highly stressful settings in the Early Phanerozoic. Trace fossil analyses indicate the combinations and ranking of stress factors affecting the colonizing fauna is diverse throughout the succession. BSU fan-delta deposits display sparse to moderate bioturbation in mid- to …