Proterozoic magmatic and tectonometamorphic evolution of the Taratash complex, Central Urals, Russia |
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| Authors: | S Sindern R Hetzel B A Schulte U Kramm Yu L Ronkin A V Maslov O P Lepikhina |
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| Institution: | (1) Institute of Mineralogy and Economic Geology, RWTH Aachen University, Wüllnerstr. 2, 52062 Aachen, Germany;(2) Institute of Geology and Paleontology, University of Münster, Corrensstraße 24, 48149 Münster, Germany;(3) Philipp-Röth-Weg 58, 64295 Darmstadt, Germany;(4) Institute of Geology and Geochemistry, The Urals branch of Russian Academy of Sciences, Pochtovy Per. 7, Yekaterinburg, 620151, Russia;(5) Mineralogical Institute, Zentrallabor für Geochronologie, WWU-Münster, Corrensstr. 24, 48419 Münster, Germany |
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| Abstract: | The Taratash Complex (TC) in the northernmost Bashkirian Anticlinorium (Middle Urals) is unique among the pre-Uralian polymetamorphic complexes along the eastern margin of the East European Craton because it experienced granulite facies peak metamorphic conditions (850–900°C/10 kbar). Herein, we constrain the post-granulite facies polystage evolution of the complex, which records various increments of the geodynamic history of the East European continental margin. Formation of granite and migmatite associated with amphibolite facies events are dated at 2,344±29 and 2,044±8 Ma (U–Pb, zircon) in different structural units. At 1,810±41 Ma, the TC was affected by a greenschist facies retrogressive metamorphism which was probably related to a stage of granite formation in the eastern part of the East European Craton. This is confirmed by a U–Pb–zircon age of 1,848±8 Ma obtained from a sheared granite in the adjacent Alexandrovskiy Complex (AC). Greenschist facies shear zones which separate different structural units of the TC formed before 1,350 Ma. Partial re-equilibration of Rb–Sr- and K–Ar-isotope systems between 1,350 Ma and 1,200 Ma is attributed to fluid flow probably induced by anorogenic magmatism in the Bashkirian Anticlinorium. Meso- to Neoproterozoic basaltic dykes indicate that the TC had been exhumed to upper crustal levels at that time. Evidence for a Grenvillian event or for the Timanian orogeny which affected other pre-Uralian complexes in the Urals is lacking. Uralian orogenic shortening and thrusting on Devonian limestones is recorded by shear zones in the AC to the east of the TC and has been dated at 300 Ma (Rb–Sr, 40Ar/39Ar). |
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| Keywords: | Ural mountains Taratash Complex Alexandrovskiy Complex U– Pb Rb– Sr Ar-Ar Geochronology |
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