Avancerad sökning

Hittade 4 uppsatser som matchar ovanstående sökkriterier.

  1. 1. Chrome spinel grains from the Komstad Limestone Formation, Killeröd, southern Sweden : a high-resolution study of an increased meteorite flux in the Middle Ordovician

    Master-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Ellinor Martin; [2014]
    Nyckelord :chrome spinel; fossil meteorites; Komstad Limestone; winonaites; Middle Ordovician; carbonate sedimentology; Earth and Environmental Sciences;

    Sammanfattning : I mellersta ordovicium var inflödet av kosmiskt material till jorden högre än idag, i sviter-na efter uppbrytningen av den L-kondritiska asteroidkroppen i asteroidbältet mellan Mars och Jupiter, vilket beri-kade den forna havsbottnen med meteoriter och kosmiskt damm. Komstadformationen i Killeröd, Skåne, innehåller ett lager särskilt rikt på L-kondritiska kromitkorn vilket indikerar en hög grad av kondensation. LÄS MER

  3. 2. A geochemical characterization of the lower part of the Miocene shield-building lavas on Gran Canaria

    Master-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Romina Peetz; [2009]
    Nyckelord :Gran Canaria; shield-building lavas; Güigüi Formation; Earth and Environmental Sciences;

    Sammanfattning : Ocean islands offer a great potential to provide information about mantle processes and the composition of the mantle. Gran Canaria is located in the centre of the Canary Island Archipelago and is well suited for such studies. A comprehensive study of the lower Miocene shield-building lavas is performed for this thesis. LÄS MER

  4. 3. Titanium- and chromium-rich opaque minerals in condensed sediments : chondritic, lunar and terrestrial origins

    Magister-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Sanna Holm; [2008]
    Nyckelord :Ilmenite; chrome spinel; 3He; lunar impact ejecta; source rock; Middle Ordovician; Late Eocene; ilmenit; kromspinell; impakt ejekta; källbergart; mellanordovicium; sen eocen; Earth and Environmental Sciences;

    Sammanfattning : Evidence from terrestrial sedimentary successions indicate that the amount of extraterrestrial material reaching Earth is not constant, but has been increased during parts of the Phanerozoic. An increase in the flux of extraterrestrial material to Earth has been proposed for the Middle Ordovician and the Late Eocene. LÄS MER

  5. 4. Extraterrestrisk och terrestrisk kromrik spinell i fanerozoiska kondenserade sediment

    Magister-uppsats, Lunds universitet/Geologiska institutionen

    Författare :Maria Nolvi; Gunilla Thorelli; [2006]
    Nyckelord :physical geography; condensed sediments; cyclic sedimentation; spherules; chrome spinels; extraterrestrial chromite; cyklisk sedimentation; kondenserade sediment; sfäruler; kromspineller; geomorphology; pedology; cartography; climatology; naturgeografi; geomorfologi; marklära; kartografi; klimatologi; extraterrestrisk kromit; Earth and Environmental Sciences;

    Sammanfattning : This study aims to assess the normal inflow of extraterrestrial chromite to Earth. The results from the investigation are compared to earlier studies of middle Ordovician Orthoceratite Limestone in which 1 - 3 extraterrestrial chromite grains ( >63 ƒÊm ) per kilogram limestone were found. LÄS MER