Sökning: "zircon textures"

Hittade 5 avhandlingar innehållade orden zircon textures.

1. 1. 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

3. 2. Proterozoic crustal evolution in southcentral Fennoscandia

   Författare :Karin Appelquist; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Transscandinavian Igneous Belt; TIB; Eastern Segment; Habo Volcanic Suite; Malmbäck Formation; U-Pb zircon ion probe dating; Nd isotopes; geochemistry; Hallandian; Danopolonian;

   Sammanfattning : The Transscandinavian Igneous Belt (TIB) and the Eastern Segment of the Southwest Scandinavian Domain reflect advanced stages of continental growth within the Fennoscandian Shield. The relationship between the two units is not clear, mainly because N-S trending shear zones of the Protogine Zone transect the border zone. LÄS MER

4. 3. Geochronology of impact structures - constraining syn- and post-impact processes using the 40Ar/39Ar and U-Pb techniques

   Författare :Maria Herrmann; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Impact structure; Dating impact events; 40Ar 39Ar dating; U-Pb dating; Siljan impact structure; Mien impact structure; Hummeln impact structure; Puchezh-Katunki impact structure;

   Sammanfattning : The discovery, at the beginning of the 20th century, that elements can transform into other elements, due to the spontaneous decay of an instable to a stable atomic nuclei, gave rise to a powerful source for age information in many fields of earth science. For impact structures, it is crucial to establish well-defined and precise ages in order to understand how impact events affect the Earth’s geo and biosphere and also with regard to possible future events that can have devastating effects on our civilization. LÄS MER

5. 4. Metamorphism in the roots of mountain belts and its effect on rock technical properties : A case study of the Eastern Segment, Sveconorwegian orogen

   Författare :Cindy Urueña; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sveconorwegian; metamorphism; hydrous fluids; microtextures; recrystallization; aggregate properties;

   Sammanfattning : Deciphering the metamorphic evolution of the roots of mountain belts is essential for understanding deep tectonic processes involved in mountain building. The Sveconorwegian orogen in southwestern Scandinavia, formed during the Rodinia assembly in the transition between the Mesoproterozoic and Neoproterozoic Eras, has been exhumed and provides access to interior deep structural levels of the ancient mountain belt. LÄS MER

7. 5. Age, origin and tectonothermal modification of the Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit, Bergslagen, Sweden

   Författare :Tobias Christoph Kampmann; Pär Weihed; Michael B. Stephens; Nils F. Jansson; Luleå tekniska universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Malmgeologi; Ore Geology;

   Sammanfattning : The Falun pyritic Zn-Pb-Cu-(Au-Ag) sulphide deposit, situated in the Palaeoproterozoic (1.9–1.8 Ga) Bergslagen lithotectonic unit in the south-western part of the Fennoscandian Shield, is one of the major base and precious metal sulphide deposits in Sweden. LÄS MER