Eclogites are important in order to understand orogenic processes, since their presence indicates high-pressure metamorphism. In northern Jämtland, Swedish Caledonides, eclogites have been found at several places in the Seve Nappe Complex (SNC). The mountain Tjeliken in the Lower Seve Nappe is one of them. Dating relates the high-pressure metamorphism to the Late Ordovican subduction of the Baltoscandian margin during the closure of the Iapetus Ocean. In this study new P-T conditions are presented for the Tjeliken eclogite based on petrographical and geochemical studies of an eclogite sampled on the top of Tjeliken in summer 2010. Peak assemblage consists of garnet + omphacite + phengite + quartz. New peak conditions are calculated to c. 2.7 GPa and 700°C. These P-T conditions are in the upper part of the quartz stability field, close to the quartz - coesite stability line. The new P-T conditions correspond well to other P-T calculations of eclogites in northern Jämtland and indicate a deep subduction of the Baltoscandian margin already in the Late Ordovician.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-196118 |
| Date | January 2013 |
| Creators | Andersson, Barbro |
| Publisher | Uppsala universitet, Institutionen för geovetenskaper |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | Självständigt arbete ; 46 |
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