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 20 of 29 for “"brachiopod"”.
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Geographical variation and evolution in the Middle Devonian brachiopod, Mucrospirifer
The Middle Devonian brachiopod, Mucrospirifer, was studied over most of its geographical and stratigraphical range in order to test the theory of punctuated equilibria. Punctuated equilibria holds that most evolution is concentrated in rapid speciation events and that the subsequent lifespan of a …
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Spatial variability in modern brachiopod assemblages: paleoecological and geochemical implications
… and paleoecological patterns in modern brachiopod faunas which may serve as analogues for ancient brachiopod assemblages. The paleoclimatic utility of delta18O in the phosphatic phase of lingulid brachiopod shells requires valve secretion in equilibrium with seawater, an assumption …
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The differentiation of races in the paleozoic brachiopod leptaena rhomboidalis wilckens
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Biology and Public Health, 1918.
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Stratigraphy, Depositional History, and Brachiopod Paleontology of Virgilian Strata of East-Central Illinois
The Virgilian outlier, upper Mattoon Formation, in east-central Illinois consists of alternating marine and nonmarine strata divided into eight modified cyclothems: Omega, Shumway, Bogota, Newton, Mint Creek, Greenup, Toledo, and Woodbury. The modified cyclothems are recognized with lower …
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Ocean warming, acidification, and chemistry of the South Pacific & North Atlantic: a brachiopod investigation
… ocean data is limited, so natural archives like brachiopods are used to understand past oceanic conditions. Brachiopod shells record seawater temperatures, chemistry, and acidity. This thesis uses brachiopods from Paterson Inlet, New Zealand (1900–2021), and the Bay of Fundy, Canada (1970–2009) …
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Quantitative Estimates of Time-Averaging in Brachiopod Shell Accumulations from a Holocene Tropical Shelf (SW Brazil)
… quantitative estimates of time-averaging for brachiopods, extending our understanding of intrinsic, or group specific controls on this process. Estimates were obtained by direct dating of individual terebratulid brachiopod shells Bouchardia rosea (Mawe) collected from modern surficial shelly …
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Quantitative Analysis of Drilling Predation Patterns in the Fossil Record: Ecological and Evolutionary Implications
… that drilling predation in Late Paleozoic brachiopod prey is relatively rare (<1% of fossil specimens are drilled) but widespread and continuously present. The intensity of drilling predation on Late Paleozoic bivalve mollusks (this is the first quantitative report of this kind) is much …
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MISSISSIPPIAN MUD MOUNDS OF DERBYSHIRE (ENGLAND, UK): FACIES ARCHITECTURE AND BIOTIC EVOLUTION
… In particular, the distribution and role of brachiopods in Mississippian mud mounds are scarcely constrained, despite brachiopods are among the most common marine benthic invertebrates in the Mississippian. The brachiopod-rich mud mounds occurring in the uppermost Monsal Dale Limestone …
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BIOMINERALIZATION AND GLOBAL CHANGE: BIOTIC RESPONSE TO THE GONDWANAN GLACIATION AND SUBSEQUENT CLIMATE WARMING
… the analysis of the record of seasonality in brachiopod shells from the late Palaeozoic, in order to assess their accuracy in recording climatic changes at the high-est resolution possible. Chapter 1 of the thesis presents an overview of the current knowledge on brachiopod shell …
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Constructing a High-Resolution Record of Silurian Paleoclimate Using Carbonate Oxygen Isotopes
… δ¹⁸O records are currently compiled from brachiopod fossils because of their resistance to diagenetic alteration, but this data is relatively sparse and not well time-resolved. Bulk carbonate δ¹⁸O data can present a more full view geographically and temporally, but is more susceptible to …
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Diagenesis and geochemical stratigraphy of Upper Pennsylvanian madera brachiopods, New Mexico
… so important in paleoceanographic research, 249 brachiopod, cement and matrix specimens from two neighboring localities (Jemez Springs and Battleship Rock), of the Upper Pennsylvanian Madera Formation were analyzed. Of which, about 86% of the Madera brachiopods are preserved in their pristine …
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Traces of Predation/Parasitism Recorded in Eocene Brachiopods from the Castle Hayne Limestone, North Carolina, U.S.A.
… fossils, was sampled to assess if early Cenozoic brachiopods from eastern North America record any traces of biotic interactions. Systematic surveys of two North Carolina quarries yielded 494 brachiopods, dominated by one species: Plicatoria wilmingtonensis (Lyell and Sowerby, 1845). Despite …
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Investigating Predation in the Fossil Record: Modern Analogs
… and cryptic or antitropical distribution of brachiopods is often explained as due to the potentially low energetic value and suspected non-palatability or toxicity of brachiopod tissues. Here we demonstrate that multiple invertebrate marine predators (crustaceans, echinoderms, and gastropods) …
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The geology and hydrocarbon potential of the Dawson Bay Formation carbonate unit (Middle Devonian), Williston Basin, North Dakota
… the carbonate lithofacies are: lithofacies B (brachiopod-echinoderm wackestones and mudstones), lithofacies C (stromatoporoid boundstones, wackestones, and mudstones), lithofacies D (gastropod-ostracod-brachiopod-echinoderm wackestones and mudstones), and lithofacies F (cryptalgal boundstone …
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Ecological, Evolutionary, and Taphonomic Comparisons of Brachiopods and Bivalves at Multiple Spatial and Temporal Scales
… the life and death assemblage of an extant brachiopod with respect to morphological variability is studied using geometric morphometrics. The results from several analyses confirm a high degree of morphological variability with little change in mean shape between the living and sub-fossil …
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Depositional environments and diagenesis of the Ratcliffe interval, Madison group (Mississippian), Williston Basin, North Dakota
… Ratcliffe is comprised of six major facies: 1) brachiopod-bryozoan-echinoderm wackestone/packstone, 2) peloid packstone/wackestone, 3) oolite-peloid packstone, 4) laminated mudstone, 5) quartz siltstone packstone, and 6) anhydrite-dolomite mudstone. These facies were deposited in a regressive …
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Middle Cambrian linguliformean brachiopods of the Pika and Sullivan formations, southern Canadian Rocky Mountains, Alberta, Canada
Linguliformean brachiopods were collected and described from the middle Cambrian Pika and Sullivan formations in the southern Canadian Rocky Mountains. These formations consist of coarse-grained grainstone interbedded with lime mudstones and siltstones in a storm-influenced, distal offshore …
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Community gradients in the Martinsburg formation (Ordovician), southwestern Virginia
… Broad overlap among these articulate brachiopod communities reflects variations within the open-shelf habitat.
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