Sökning: "Sediment reworking"

Hittade 5 avhandlingar innehållade orden Sediment reworking.

  1. 1. Transport by Benthic Macrofauna: Functional Classification and Biogeochemical Response

    Författare :Stina Lindqvist; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Marine sediments; Early diagenesis; Bioturbation; Functional groups; Benthic fluxes; Imaging; Ecosystem function; Sediment reworking; Transport proxies; Fluorescent particles;

    Sammanfattning : Burrowing and reworking activities by benthic macrofauna regulate rates and pathways during organic matter mineralisation in bioturbated sediments. In so doing, they also affect the overall cycling of elements crucial in the biosphere (e.g. C, N, P, Fe, Mn and S). LÄS MER

  3. 2. Crustal evolution of the Arabian–Nubian Shield : Insights from zircon geochronology and Nd–Hf–O isotopes

    Författare :Fitsum Girum Yeshanew; Victoria Pease; Martin J. Whitehouse; Robert J. Stern; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Gondwana; Arabian–Nubian Shield; Azania; zircon U–Pb–O–Hf isotopes; Nd isotopes; Cambrian Sandstones; juvenile; pre–Neoproterozoic; reworking; Geology; geologi;

    Sammanfattning : The Arabian–Nubian Shield (ANS) represents a major site of juvenile Neoproterozoic crustal addition on Earth and documents Neoproterozoic tectonics bracketed by two supercontinent cycles, namely the fragmentation of Rodinia and the amalgamation of Gondwana. There is general consensus that the ANS formed by juvenile magmatic arc accretion and subsequent shield–wide post–tectonic magmatism. LÄS MER

  4. 3. Evolution of continental crust in the Proterozoic : growth and reworking in orogenic systems

    Författare :Andreas Petersson; Berggrundsgeologi; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; crustal reworking; Proterozoic; O-isotopes; Lu–Hf; U–Pb; zircon; Crustal growth;

    Sammanfattning : To understand the growth of continental crust, the balance between juvenile mantle derived extraction, infracrustal reworking and crustal recycling, needs to be estimated. Since the beginning of the century, the use of coupled in situ zircon U–Pb, Lu–Hf and O isotope analyses as a tool to address these questions have increased exponentially. LÄS MER

  5. 4. Diatom and Sedimentological Investigations on West Antarctic Shelf Sediment

    Författare :Charlotte Sjunneskog; Bjorg Stabell; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; Antarctica; climate change; diatom abundance; geochemistry; Geovetenskap; Earth sciences; Geovetenskap; Quarternary Geology; kvartärgeologi;

    Sammanfattning : Climate and environmental change following the retreat of the last glacial ice sheet in the Antarctic Peninsula has been interpreted, employing diatom abundance, relative abundance of Chaetoceros resting spores and diatom assemblages as proxies. These together with sedimentological data and radiocarbon dating, suggest four major events that can be further subdivided. LÄS MER

  7. 5. Past environment and sediment dynamics in the Black Sea-Caspian Sea region from Southern Russian loess sequences

    Författare :Chiara Amalia Költringer; Thomas Stevens; Bjarne Almqvist; Ian Snowball; Kathryn Fitzsimmons; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Loess deposits are excellent past climate and environment archives and contain records of aeolian mineral dust accumulation. Loess deposits stretch across Eurasia and sequences along the Lower Volga in the Northern Caspian lowland in the South East European Plain represent a key link between European and Asian loess. LÄS MER