Sökning: "Facies"

Visar resultat 21 - 25 av 57 avhandlingar innehållade ordet Facies.

1. 21. How do fluids move through rocks? : High fluxes of CO2 in the Earth's crust

   Författare :Barbara Kleine; Alasdair Skelton; Iain Pitcairn; Sandra Piazolo; Jaroslaw Majka; Zhihong Zhao; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; metamorphic fluid flow; blueschist preservation; fluid-rock interaction; Geology; geologi;

   Sammanfattning : Metamorphic hydrous, CO2-bearing fluids play a critical role in the global carbon cycle. However, how big this influence is on the global carbon cycle and therefore on global climatic processes, is unknown. The actual amount of CO2 which is released into the atmosphere due to metamorphic processes is still debated. LÄS MER

3. 22. Middle ordovician conodonts from the Atlantic faunal region and the evolution of key conodont genera

   Författare :Jianhua Zhang; Anita Löfgren; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Conodonts; Middle Ordovician; Biostratigraphy and lithofacies; Evolution; Atlantic Faunal Region; Earth sciences; Geovetenskap; allmän och historisk geologi; General and Historical Geology;

   Sammanfattning : This thesis consists of seven separate articles that are mainly concerned with Middle Ordovician conodonts. The studied conodont specimens were obtained from three Middle Ordovician sections in south China and four Middle Ordovician sections in Sweden. LÄS MER

4. 23. Pressure, temperature and time constraints on tectonic models for southwestern Sweden

   Författare :Eric Austin Hegardt; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sveconorwegian; Gothian; Hallandian; U‐Pb zircon ion probe dating; Sm-Nd garnet dating; thermobarometry; continental subduction; Eastern Segment; Median Segment; Western Segment;

   Sammanfattning : In this work, a number of key localities have been investigated in detail in order to provide precise constraints on models for the tectonic evolution of southern Sweden. The new data presented in this thesis show that there are large differences in terms of pre-Sveconorwegian tectonic evolution between the Eastern and Median-Western Segments situated on either side of the Mylonite Zone, a major shear zone as well as a structural and lithological boundary. LÄS MER

5. 24. The metamorphic history of Naxos (central Cyclades, Greece) : Deciphering the Oligocene and Miocene exhumation events

   Författare :Alexandre Peillod; Uwe Ring; Alasdair Skelton; Arne Willner; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Cycladic Blueschist Unit; exhumation; fluid flow; geothermobarometry; Hellenide orogen; Rb-Sr dating; subduction-zone metamorphism; Heat flow; Lower crust; extensional domain; Metamorphic core complex; Geology; geologi;

   Sammanfattning : High pressure, low temperature (HP-LT) rocks observed at the surface of the Earth are evidence ofpast subduction zones. Understanding the tectonics processes that control the exhumation of HP-LT metamorphic rocks in these subduction zones requires full comprehension of the pressure-temperature-time (P–T–t) cycle that the rocks experienced. LÄS MER

7. 25. The tectonic evolution of the western part of the Svecofennian orogen, central Sweden : Insight from U/Pb and 40Ar/39Ar geochronology at Forsmark

   Författare :Tobias Hermansson; Berggrundsgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; physical geography; Geology; Svecofennian orogen; Tectonic models; Tectonic cycles; Uplift; Cooling; Ductile deformation; Geochronology; U Pb; 40Ar 39Ar; Geologi; fysisk geografi; Petrology; mineralogy; geochemistry; Petrologi; mineralogi; geokemi;

   Sammanfattning : The Forsmark area, in the western part of the Svecofennian orogen, central Sweden, is situated between two major Palaeoproterozoic tectonic domains that show contrasting histories with respect to timing of igneous activity, ductile deformation and metamorphism. At Forsmark, WNW to NW trending, ductile deformation belts anastomose around tectonic lenses with an inferred lower degree of ductile strain. LÄS MER