Sökning: "Berggrundsgeologi"

Visar resultat 11 - 15 av 65 avhandlingar innehållade ordet Berggrundsgeologi.

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

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

   Sammanfattning : 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. LÄS MER

3. 12. Terrestrial consequences of hypervelocity impact – shock metamorphism, shock barometry, and newly discovered impact structures

   Författare :Sanna Alwmark; Berggrundsgeologi; []
   Nyckelord :Impact cratering; Impact structure; Shock metamorphism; Shock barometry; Quartz; Planar deformation features; Siljan; Målingen; Hummeln;

   Sammanfattning : Impact cratering was once considered a rare geological process of no, or little, importance to the evolution of the Solar System and planet Earth. After more than 50 years of space exploration and the discovery of numerous (~190 as of October 2016) impact structures on Earth, this view has changed, and it is now clear that impact craters are in fact one of the most common morphological features on solid bodies in the Solar System. LÄS MER

4. 13. Sveconorwegian orogenesis in the southwestern Baltic Shield - Zircon geochronology and tectonothermal setting of orthogneisses in SW Sweden

   Författare :Jenny Andersson; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Petrology; Geologi; fysisk geografi; physical geography; Geology; structural markers; augen gneiss; orthogneiss; migmatite; ion microprobe; Pb-Pb evaporation; U-Pb; geochronology; zircon; Sweden; Mylonite Zone; Western Segment; Sveconorwegian orogen; Eastern Segment; mineralogy; geochemistry; Petrologi; mineralogi; geokemi;

   Sammanfattning : The Mylonite zone (MZ) is a prominent late-Sveconorwegian lithological terrane boundary in the SW Baltic Shield along which large-scale crustal block movements took place during the Sveconorwegian orogeny. The southern section of the MZ also defines a conspicuous metamorphic break separating upper amphibolite and high-pressure granulite facies rocks in the parautochthonous Eastern Segment (ES), from middle amphibolite facies rocks in the overlying Western Segment (WS). LÄS MER

5. 14. The lower and middle Cambrian of Sweden: trilobites, biostratigraphy and intercontinental correlation

   Författare :Niklas Axheimer; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sedimentologi; Paleontologi; Palaeontology; fysisk geografi; Geologi; physical geography; Geology; Sweden; correlation; trilobites; biostratigraphy; Cambrian; Sedimentology;

   Sammanfattning : This thesis is based on studies of Cambrian successions in Sweden, with particular focus on the middle Cambrian biostratigraphy and its correlative relationship to the proposed global agnostoid zonation. The investigated material, mainly trilobites, was collected from both outcrops and drill cores from five provinces in Sweden: Skåne (Scania), Öland, Västergötland, Jämtland and Lapland. LÄS MER

7. 15. Metamorphic zircon formation in gabbroic rocks – the tale of microtextures

   Författare :Victoria Beckman; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Zircon formation; metamorphism; prograde; gabbr; zircon; baddeleyite; zircon; baddeleyite; metamorphic; prograde; zircon textures;

   Sammanfattning : Dating of metamorphic events is crucial for the understanding and reconstruction of large-scale geological processes such as orogenesis. Zircon is one of the most commonly used minerals for dating of igneous and metamorphic events. Zircon incorporates uranium and excludes lead during crystallization, and with time the uranium decays to lead. LÄS MER