The Sveconorwegian orogen of southern Scandinavia: setting, petrology and geochronology of polymetamorphic high-grade terranes
Leaders: Jenny Andersson, Geological Survey of Sweden (SGU), firstname.lastname@example.org; Bernard Bingen, Geological Survey of Norway (NGU), email@example.com; David Cornell, Earth Sciences Centre, Gothenburg University, firstname.lastname@example.org; Leif Johansson, Geobiosphere Science Centre, Lund University, email@example.com; Charlotte Möller, Geological Survey of Sweden (SGU), firstname.lastname@example.org; Ulf Söderlund, Geobiosphere Science Centre, Lund University, email@example.com
Geological context and scope of excursion: This pre-conference excursion will be held in the Sveconorwegian orogen of southern Scandinavia, a tectonic counterpart to the Grenville orogen in Canada. Here, the shield area exposes an exquisite traverse through a deep-seated Precambrian continent-continent collision zone(s). The orogen is composed of several Proterozoic gneiss segments attached along the southwestern margin of the Baltica proto-continent during a succession of compressional orogenic phases at between 1.13-0.96 Ga. A final continent-continent collision phase at 0.98-0.96 Ga involved high-pressure granulite metamorphism and emplacement of eclogites in the southeastern part of the orogen. The excursion participants will be taken to well exposed high-grade metamorphic domains, including the Southwest Swedish granulite region that exhibits a polymetamorphic high-grade gneiss complex with charnockites, high-pressure granulites and tectonically emplaced eclogitised units.
The excursion aims to highlight the combination of field geology, metamorphic petrology and application of different geochronological-geochemical analytical techniques to pin down the metamorphic conditions and the timing of tectonothermal events of high-grade metamorphic complexes. The individual excursion stops have been selected to show key localities used to construct, characterise and directly date the P-T-t evolution and tectonic build up of the eastern Sveconorwegian orogen in Scandinavia. Our purpose with the excursion is to bring together structural geologists, metamorphic petrologists, isotope geochemists, geochronologists, and other geoscientists to combine their expertise and discuss how to model tectonic cycles and thereby, understand the crustal evolution of our continents.
The outline of the excursion follows three main themes:
(I, day one) Tectonic build up of the orogenic front; the transition between weakly to unmetamorphosed rocks of the pre-Sveconorwegian craton and the high-grade gneisses of the Sveconorwegian Southwest Swedish granulite complex.
(II, day two) Geochronology and setting of eclogites, granulites, and charnockites.
(III, day three and four) Terrane boundaries and lithotectonic build up of the Sveconorwegian orogen.
This pre-conference excursion is thematically linked to a symposia on "Geochronology and Isotope geology" held in the IGC 2008 meeting, sub-section entitled "Geochronology of metamorphic reactions and deformation in high-grade orogenic settings" (sub-section MPC-02). Convenors: Jenny Andersson, David Cornell and Ulf Söderlund.