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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Analysis of Laminated Sediments from Lake DV09, Northern Devon Island, Nunavut, Canada

Courtney Mustaphi, Colin 16 September 2010 (has links)
A 147cm sediment core from Lake DV09, northern Devon Island, Nunavut, Canada (75° 34’34”N, 89° 18’55”W) contains annually-laminated (varved) sediments, providing a 1600-year record of climate variability. A minerogenic lamina deposited during the annual thaw period and a thin deposit of organic matter deposited during the summer and through the winter, together form a clastic-organic couplet each year. The thinnest varves occur from AD800-1050, and the thickest from AD1100-1300, during the Medieval Warm Period. The relative sediment density is also highest during this period suggesting increased sediment transport energy. The coldest period of the Little Ice Age appears to be during the AD1600s. Varve widths over the past century indicate climate warming in the region. / This research program was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS). A tuition bursary from Ultramar Inc. also helped in making this research possible. Logistical support was provided by the Polar Continental Shelf Project (PCSP Contribution number 04508).
32

Analysis of Laminated Sediments from Lake DV09, Northern Devon Island, Nunavut, Canada

Courtney Mustaphi, Colin 16 September 2010 (has links)
A 147cm sediment core from Lake DV09, northern Devon Island, Nunavut, Canada (75° 34’34”N, 89° 18’55”W) contains annually-laminated (varved) sediments, providing a 1600-year record of climate variability. A minerogenic lamina deposited during the annual thaw period and a thin deposit of organic matter deposited during the summer and through the winter, together form a clastic-organic couplet each year. The thinnest varves occur from AD800-1050, and the thickest from AD1100-1300, during the Medieval Warm Period. The relative sediment density is also highest during this period suggesting increased sediment transport energy. The coldest period of the Little Ice Age appears to be during the AD1600s. Varve widths over the past century indicate climate warming in the region. / This research program was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS). A tuition bursary from Ultramar Inc. also helped in making this research possible. Logistical support was provided by the Polar Continental Shelf Project (PCSP Contribution number 04508).
33

The classification and interpretation of tin smelting remains from South West England : a study of the microstructure and chemical composition of tin smelting slags from Devon and Cornwall, and the effect of technological developments upon the character of slags

Malham, Albertine January 2010 (has links)
Artefacts relating to tin smelting from tin mills or 'blowing houses' in Devon and Cornwall, plus material from smelting sites that cover a range of dates from the Bronze Age through to the 19th Century, were examined: these include metallic tin, furnace linings, ore samples and slag. Analysis of tin slags from over forty sites was carried out, to determine microstructure and chemical composition. Techniques employed included optical and scanning electron microscopy, X-ray fluorescence and ICP mass spectrometry. Analysis indicates that slag appearance and composition are heavily influenced by local geology. Composition, particularly iron content, is shown to have a strong effect on slag melting point and viscosity, and the implications for the purity of metal produced are discussed. Bringing together the evidence provided by slag chemistry, documentary sources and smelting remains in the archaeological record, changes in tin smelting technology through time, and the consequences thereof, are considered.
34

Frost Heave: New Ice Lens Initiation Condition and Hydraulic Conductivity Prediction

Azmatch, Tezera Firew Unknown Date
No description available.
35

Analysis of Laminated Sediments from Lake DV09, Northern Devon Island, Nunavut, Canada

Courtney Mustaphi, Colin 16 September 2010 (has links)
A 147cm sediment core from Lake DV09, northern Devon Island, Nunavut, Canada (75° 34’34”N, 89° 18’55”W) contains annually-laminated (varved) sediments, providing a 1600-year record of climate variability. A minerogenic lamina deposited during the annual thaw period and a thin deposit of organic matter deposited during the summer and through the winter, together form a clastic-organic couplet each year. The thinnest varves occur from AD800-1050, and the thickest from AD1100-1300, during the Medieval Warm Period. The relative sediment density is also highest during this period suggesting increased sediment transport energy. The coldest period of the Little Ice Age appears to be during the AD1600s. Varve widths over the past century indicate climate warming in the region. / This research program was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS). A tuition bursary from Ultramar Inc. also helped in making this research possible. Logistical support was provided by the Polar Continental Shelf Project (PCSP Contribution number 04508).
36

The shaping of 'West Barbary' : the re/construction of identity and West Country Barbary captivity

Esra, Jo Ann January 2013 (has links)
Divided into three parts, this thesis maps a cultural history of Barbary captivity; concentrating on the early 17th century leading up to the Civil Wars; an aspect of British-Muslim contact within which the West Country is overrepresented in the archives. However, this wealth of material contrasts sharply with the paucity of popular and public-facing representations. Situating these accounts within wider contexts, this thesis investigates this contrast, exploring the social, cultural, emotional and economic impact of Barbary captivity upon understandings of place and identity. The first part examines representations of being taken captive, the terror and distress of West Country inhabitants, and the responses and concerns of the authorities. The on-going failure to protect the region and its seafarers exacerbated this distress, producing marginalised geographies of fear and anxiety. The second part explores the themes of memory and identity, arguing that how captives were remembered and forgotten had implications for localised and national identities. For those held in Barbary, families and communities petitioned and undertook ransom collections to redeem the captives, providing reminders to the authorities and appealing for wider remembrance as part of the processes of Christian compassion. Nevertheless, the majority of captives were ‘forgotten’, neither ransomed nor leaving their individual mark within the historical record. This part concludes with a discussion of the role of memory in managing and articulating the ‘trauma’ of captivity. The final part examines mobile and fluid identities, concentrating on returning captives and Islamic converts. Early modern theories of identity situated the humoral body of the captive as susceptible to ‘turning Turk’, contributing to wider negotiations of national, ethnic and religious identities. Cultural anxieties were preoccupied with the ill-defined borders of the geographically displaced material body, generating mutable, hidden and shameful identities. In conclusion, sites of cultural trauma are produced, indicated by the subsequent silence regarding this aspect of localised history.
37

Korelace zástupců čeledi Spathognathodontidae (Conodonta) na hranici silur/devon v profilech Na Požárech a Praha-Radotín (pražská synforma) / Family Spathognathodontidae (Conodonta) from the Silurian/Devonian boundary (sections Na Požárech and Praha-Radotín; Prague Synform) and its biostratigraphical correlation

Hušková, Aneta January 2017 (has links)
This work is focused on conodont biostratigraphy of the Silurian/Devonian boundary interval in the Prague Synform. The Na Požárech and Praha-Radotín sections were selected in order to study conodont diversity and changes in conodont faunas in different carbonate facies - shallower and deeper-water limestones around the Silurian/Devonian boundary and also to test the assumption, whether differences in bathymetry affect the diversity of taxa of the family Spathognathodontidae. In total 22 samples were analysed, particularly 13 samples from the section Praha-Radotín and 9 samples from the section Na Požárech. All samples were processed in laboratory and the obtained conodont material was studied in detail. The conodont material is abundant in both sections (more than thousand elements) and shows a high diversity and disparity in the family Spathognathodontidae. In total 17 taxa were identified and a new species Zieglerodina petrea is described. This new taxon is easily recognizable because of a distinct morphology and could be usefull for the identification of the base of Devonian in the Prague Synform. Its potential use in global correlation will, however, need further and thorough studies. Also conodonts of the family Icriodontidae are surprisingly abundant in both sections. Thin sections (13 from...
38

SCF ve spodním paleozoiku barrandienské oblasti / SCF in Lower Palaeozoic sediments of the Barrandian area

Kovář, Vojtěch January 2020 (has links)
1 Abstract In recent years, the term small carbonaceous fossils (SCFs) has been established to accomodate fragile organic-walled fossils of micro- to mesoscopic size that are usually extracted by means of the 'low-manipulation HF extraction' method. This method has so far only been utilized by several authors and no reports have been published on the usage of the method on samples from the Barrandian area. To test the applicability of the method, samples from the Barrandian area were processed. The samples came from eleven localities representing six stratigraphic units (Paseky Shale, Jince Formation, Letná Formation, Kosov Formation, Daleje Shale and Roblín Member). All the units have been studied before by 'standard' methods of palynological processing. Various previously unreported fossils are described, including wiwaxiid sclerites, putative chaetognath remains and acritarch clusters. Furthermore, it is discovered, that the 'low-manipulation HF extraction' can also be used for extraction of originally calcareous fossils. The pilot study provides a further proof that the 'low-manipulation HF extraction' is a useful tool with the potential to significantly expand our knowledge of fossil assemblages. Key words: Small carbonaceous fossils, Cambrian, Ordovician, Devonian, Barrandian area
39

⁴⁰AR/³⁹AR geochronology of biotite from ductile shear zones of the Ellesmere-Devon crystalline terrane, Nunavut, Canadian Arctic

Caswell, Brandon Christopher 01 January 2018 (has links)
This thesis presents a 40Ar/39Ar geochronological analyses of biotite from thin ductile shear zones in Paleoproterozoic granulite-facies gneisses from the Ellesmere-Devon crystalline terrane, Nunavut, Canada. The gneisses are part of the Paleoproterozoic Thelon tectonic zone. U-Pb dates of zircon show that the gneisses have magmatic protolith ages ranging from 2007–1958 Ma. The quartzofeldspathic gneisses in southeast Ellesmere Island display centimeter-scale E- to NE-striking sinistral and dextral mylonite zones offsetting pegmatitic dikes that are the last stage of ductile deformation of the basement rocks. Samples were taken from nearshore outcrops at Hayes Fiord, Pim Island, NE of the Leffert Glacier and NW of Cape Isabella. Biotite clusters replace orthopyroxene as the result of post-granulite facies metamorphism in the gneisses. Biotite in mylonitic and ultramylonitic fabrics is found as flattened clusters and also as individual crystals defining shear bands related to mylonitization. Eight samples were dated, including biotite from five mylonites, one deformed pegmatite, one tonalite and muscovite from a pegmatite. Major element X-ray maps demonstrate that the biotite is chemically homogenous. Backscattered electron images and electron dispersive spectroscopy via scanning electron microscopy confirm that biotite lacks intercrystalline layering with other K phases. Step-heating analysis of mica at the University of Vermont yielded Paleoproterozoic 40Ar/39Ar ages. The apparent age spectra form plateau ages in all but one mylonite sample. Biotite from a protomylonite was 2051 ± 26 Ma, older than the protolith ages obtained from U-Pb zircon geochronology, and most likely indicates excess Ar. Pegmatitic muscovite was 1977 ± 35 Ma. Biotite dates range from 1874 ± 13 Ma to 1838 ± 14 Ma for the five mylonites without excess Ar. Biotite dated from ductile shear zones signals the latest deformation in the basement, which was active as early as 1887 Ma.
40

Analysis of Laminated Sediments from Lake DV09, Northern Devon Island, Nunavut, Canada

Courtney Mustaphi, Colin January 2009 (has links)
A 147cm sediment core from Lake DV09, northern Devon Island, Nunavut, Canada (75° 34’34”N, 89° 18’55”W) contains annually-laminated (varved) sediments, providing a 1600-year record of climate variability. A minerogenic lamina deposited during the annual thaw period and a thin deposit of organic matter deposited during the summer and through the winter, together form a clastic-organic couplet each year. The thinnest varves occur from AD800-1050, and the thickest from AD1100-1300, during the Medieval Warm Period. The relative sediment density is also highest during this period suggesting increased sediment transport energy. The coldest period of the Little Ice Age appears to be during the AD1600s. Varve widths over the past century indicate climate warming in the region. / This research program was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC), and the Canadian Foundation for Climate and Atmospheric Sciences (CFCAS). A tuition bursary from Ultramar Inc. also helped in making this research possible. Logistical support was provided by the Polar Continental Shelf Project (PCSP Contribution number 04508).

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