Sökning: "oxygen isotopes"

Visar resultat 1 - 5 av 25 uppsatser innehållade orden oxygen isotopes.

  1. 1. Investigating surface spring snow : Changes in the isotopic composition and conductivity along an orographic precipitation gradient in northern Fennoscandia

    Kandidat-uppsats, Umeå universitet/Institutionen för ekologi, miljö och geovetenskap

    Författare :Sara Andersson; [2023]
    Nyckelord :stable isotopes; snow; precipitation; hydrology; orography; earth science;

    Sammanfattning : Stable isotopes of oxygen (O18) and hydrogen (H2) are used as proxies of past climates when ice preserved in the polar icecaps. The main assumption when doing paleoclimatic reconstructions using these isotopes is that the isotopic composition of the snow that turned into ice reflect the present temperature of the planet during deposition. LÄS MER

  3. 2. Arctica Islandica – Annually Banded Mollusc Offers High Temporal Resolution Record Into End Of North Sea Little Ice Age

    Master-uppsats, Uppsala universitet/Institutionen för geovetenskaper

    Författare :Eilidh Towers; [2022]
    Nyckelord :sclerochronology; Arctica islandica; palaeoenvironments; Little Ice Age; radiocarbon reservoir effect;

    Sammanfattning : Sclerochronology affirms the well-established fact that banded growth increments in marine molluscs accurately record oscillations in climate and environment for the past millennia or more. This study considers how such records can enhance understanding of environmental shifts across the 18th to 20th centuries. LÄS MER

  4. 3. Origin of Silicic Magmatism at the Katla Volcano, South Iceland

    Master-uppsats, Uppsala universitet/Institutionen för geovetenskaper

    Författare :Caroline Svanholm; [2021]
    Nyckelord :Katla volcano; Iceland; high-silica rocks; oxygen isotopes; AFC processes; Vulkanen Katla; Island; kiselrika bergarter; syreisotoper; AFC-processer;

    Sammanfattning : Katla volcano, South Iceland, is a bimodal volcanic system hosting an unusual high number of silicic rocks within a basaltic rift setting. The petrogenesis of silica-rich rocks at Katla is controversial and two end-member hypotheses have been suggested. LÄS MER

  5. 4. The Eemian Baltic Sea hydrography and paleoenvironment based on foraminiferal geochemistry

    Master-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Julia Chonewicz; [2020]
    Nyckelord :trace elements; benthic foraminifera; last interglacial; temperature reconstruction; geochemistry; Earth and Environmental Sciences;

    Sammanfattning : I den här masteruppsatsen undersöktes geokemin i kalkskalen av bottenlevande foraminiferer från Anholt (Kattegat), Ristinge (Bälthavet) och Obrzynowo (Egentliga Östersjön), för att rekonstruera de hydrografiska förhållanden i Östersjön och paleomiljön under den senaste interglacialen (130 - 115 ka BP). De variabler som analyserades innefattade Mg/Ca, Ba/Ca och Mn/Ca samt stabila syre- och kolisotoper (δ18O och δ13C) i kombination med data från tidigare studier och modern hydrografi. LÄS MER

  7. 5. Assessing the biodiversity crisis within the Triassic-Jurassic boundary interval using redox sensitive trace metals and stable carbon isotope geochemistry

    Master-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Halla Margrét Viðarsdóttir; [2020]
    Nyckelord :Stenlille; Schandelah; redox conditions; C-isotopes; marine sediments; trace elements; enrichment factors; mass extinction; Triassic – Jurassic boundary; Earth and Environmental Sciences;

    Sammanfattning : Around the Triassic-Jurassic-Boundary time interval, a severe mass extinction event occurred, which has been associated to volcanism of the Central Atlantic Magmatic Province (CAMP). Significant amounts of greenhouse gases as carbon dioxide (CO2) or methane (CH4) and other volatiles are suggested to have been released into the atmosphere, leading to global warming with subsequent impact on the biosphere. LÄS MER