Advanced search

Found 4 swedish dissertations matching the above criteria.

  2. 1. The micrometeorite flux to Earth through the Phanerozoic Eon : Reconstructed using sediment-dispersed extraterrestrial spinels

    Author : Ellinor Martin; Kärnfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; chromite; chrome spinel; micrometeorites; Phanerozoic; asteroid breakup; ordinary chondrites; 3He anomalies; lunar impacts; ice age; impact craters; zircons;

    Abstract : The purpose of this thesis is to add an astronomical component to the history and evolution of Earth by reconstructing the micrometeorite flux to Earth at different time intervals during the Phanerozoic Eon, using sediment-dispersed extraterrestrial spinel group minerals as a proxy. Chromite and chrome spinel are common refractory members of the spinel group, occurring in both extraterrestrial and terrestrial rocks. READ MORE

  4. 2. The flux of extraterrestrial spinels to Earth associated with He-3 anomalies in Cenozoic and Ordovician sediments

    Author : Samuele Boschi; Kärnfysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Chromite; He-3 anomaly; Cenozoic; mid-Ordovician; asteroid breakup; ordinary chondrites; Popigai ejecta; iridium anomaly; Zircons; ice age;

    Abstract : The main goal of this thesis is to reconstruct the flux of extraterrestrial matter to Earth in specific time intervals of our past in order to add an astronomical dimension to the understanding of Earth's history. To accomplish this, extraterrestrial chrome-spinel grains have been extracted and analysed. READ MORE

  5. 3. The flux of extraterrestrial matter to Earth as recorded in Paleogene and Middle Ordovician marine sediments

    Author : Anders Cronholm; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; L-chondite; sediment-disperesed; chromite; break-up event; Arenig-Llanvirn;

    Abstract : This thesis aims at reconstructing events in the solar system, mainly collisional events in the asteroid belt, by searches for extraterrestrial minerals in Paleogene and Middle Ordovician marine sediments on Earth. Recent empirical evidence show that Earth has experienced a few brief periods during the Phanerozoic when the flux of extraterrestrial matter significantly increased. READ MORE

  6. 4. Traces in Earth's geological record of the break-up of the L-chondrite parent body 470 Ma

    Author : Carl Alwmark; Berggrundsgeologi; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; L chondrite; Middle Ordovician; extraterrestrial material; meteorite flux; Sweden;

    Abstract : This thesis deals with signatures in sediments on Earth related to the L-chondrite parent body break-up event at 470 Ma. The aim of this thesis is twofold: (1) investigate if the increased flux of extraterrestrial material to Earth, following the disruption of the L-chondrite parent body included larger, asteroid-sized bodies (2) try to develop new methods and tools for finding and classifying relict cosmic material in sediments. READ MORE