Major tectonic processes illustrated with examples from the Geology

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,Major tectonic processes illustrated with examples from the Geology of Norway,Intro and overview of the Late Proterozoic to Permian tectonic evolution,Baltica becomes a tectonic entity,The margins of Baltica,Early deformation along the Caledonian margin,Ophiolites and island arcs,Towards continental collision and the Scandian orogeny,Late to post-orogenic tectonic processes,Late Palaeozoic continental rifting,Start of a new Wilson cycle,The start:,Short overview of the main age provinces of Fennoscandia,(Baltic shield),Super-continent cyclisity?,Main events of the Late Proterozoic,:,Late Proterozoic,Timanian,(,Baikalian,/,Cadomian,) deformation,in Arctic Norway,Rifting along the future Caledonian margin of the,Fennoscandian,shield, major igneous complexes,diatremes,and dykes,The,palaeocontinent,of Baltica becomes an tectonic entity,The,Vendian glaciation,(,before,595 Ma, at ca 620 Ma?),The,Seve,transitional continental - oceanic crust,The sedimentary basins and establishment of a rift margin,Sparagmites,to the,Cambro,-Silurian foreland sequence,The main geological layout of the Baltic Shield, 2.5 Ga,Ga,1.75-1.5 Ga,1.2 - 0.93 Ga,Supercontinent cyclisity?,From Rodinia to Pangea? Does the earths continental lithospheric,plates assemble and rift apart in longer term cycles?, 500 myr.,cycle?,A speculative,Rodinia,reconstruction,ca 750 Ma,Supercontinent PANGEA in,the late Permian ca 255 Ma,From: Roberts & Siedlecka 2002,The story is more complicated,than a simple break-up of,the supercontinent!,F.example:,In the Mid- to Late Vendian,we have the Timanian,Orogeny; (prev. referred,to as the Baikalian),in the now Arctic Norway.,This reconstruction,correlates the Timanian,orogeny in time and space with,the Cadomian of Europe,Eastern US and Canada,TIME: 600-570 Ma,NB!,Notice,uncertain,position of,Laurentia,From Torsvik and Cox, for further explanation see:,platemotions/500-400/,Notice the Gondwana-wide,Cadomian Pan-African,deformation belts, also,affecting the margin of Baltica,(Timanian),BALTICA CERTAINLY A,SEPARATE CONTINENT,AT 550 Ma,MAGMATIC ROCKS ASSOCIATED WITH,RIFTING OF BALTICA,Northern Scandianvia,:,Seiland Igneous Province: Ultramafics, gabbros syenites etc,Gabbros 570-560 Ma (,Unpubl. data R.J. Roberts; pers com. 2003),Nefeline-syenite-pegmatite: 531 and 523 2 Ma,(Pedersen et al. 1989),Kalak nappe complex dyke complex(es),(not yet dated),Central Scandinavia:,Sarek sheeted dykes: 608 1 Ma,(Svenningsen 1999),Ottfjellet dykes: 665 10 Ma,(Ar, Claesson & Roddick 1983),Southern Scandinavia:,Lavas within the Hedemark “sparagmite” basin,(not yet dated),Atly,dykes:,(pre 450 Ma, not yet dated),Hunnedalen dykes: 850 Ma,(Ar, Walderhaug et al. 1999),Egersund dykes: 616 3 Ma,(Bingen et al. 1997),Fen complex: 585 Ma,(Ar, Meert et al. 1999),From Meert et al. 1999,Fen complex,585 Ma,Hedemark lava ?,Atly dykes ?,Sarek dykes 608 Ma,Ottfjallet dykes 665 Ma,Seiland IC 570-560 Ma,Egersund dykes 616Ma,Fen 585 Ma,Second stage w nefeline-,syenites U/Pb z. 531-523 Ma,600-570Ma,VARIOUS VENDIANCAMBRIAN,RECONSTRUCTIONS,Varanger,Glaciation,older than,595 Ma, 620 Ma?,Southern hemisphere, major ( 90,0,) anticlockwise rotation,Cambrian - Ordovician,older,than,595 Ma,ca 620 Ma?,Late-Proterozoic to Cambrian stratigraphy in Scandinavia,545 Ma,Traditional 2-D conseptual model,From: Kumpulainen and Nystuen 1985,From: Kumpulainen and Nystuen 1985,ca 620 Ma,ca 610-545 Ma, nb! remember Timanian def in the north,First signs of collision:,Eclogite facies,metamorphism,Seve Nappe complex;,arc-collision?,From Torsvik and Cox, for further explanation see:,platemotions/500-400/,608 1 Ma,Present day Norwegian Sea analogue to a Seve nappe complex,Transitional continental - oceanic crust preserved in the Seve nappe complex,The telescoped,Caledonian,margin of Baltica,WHERE DO WE FIND EVIDENCE FOR,EARLY-CALEDONIAN (PRE-SCANDIAN),TECTONIC EVENTS ALONG THE,CALEDONIAN MARGIN OF BALTICA?,1,1) W- Finnmark/E-Troms,(pre-490 Ma),2,2) Central Sweden-Nordland,(pre-490 Ma),3,3) Otta-Foldal-Rros,(pre-470 Ma),4,4) Atly,(pre 450 Ma),5,5) Jren (?),6,6) Cromite in Seds in foreland,ca 470,