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Hittade 2 avhandlingar som matchar ovanstående sökkriterier.

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

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

   Sammanfattning : 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. LÄS MER

3. 2. The origin of the marine Lockne impact structure, Jämtland

   Författare :Erik Sturkell; Christian Keoberl; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Lockne; Jämtland; Earth sciences; Geovetenskap; allmän och historisk geologi; General and Historical Geology;

   Sammanfattning : The Lockne impact structure in Jämtland (63o00'20"N, 14o49'30"E), formed in the Middle Ordovician at approximately 455 Ma. The structure is a concentric crater with a total diameter of 13.5 km. The impact took place in a marine environment. LÄS MER