Palaeozoic accretion of Gondwana-derived terranes to the East European Craton: recognition of detached terrane fragments dispersed after collision with promontories
Published:January 01, 2006
J. A. Winchester, T. C. Pharaoh, J. Verniers, D. Ioane, A. Seghedi, 2006. "Palaeozoic accretion of Gondwana-derived terranes to the East European Craton: recognition of detached terrane fragments dispersed after collision with promontories", European Lithosphere Dynamics, D. G. Gee, R. A. Stephenson
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Recent work in Central Europe, combined with emerging information about basement massifs in SE Europe and NW Turkey, permits a new look at the relationships between crustal blocks abutting the East European Craton (EEC) along the Trans-European Suture Zone (TESZ). The simplest model indicates that the end-Cambrian establishment of the Bruno-Silesian, Lysogory and Malopolska terranes close to their present location on the SW margin of the EEC formed a major promontory on this margin of the continent. Moesia may also have formed part of this block. Both late Ordovician accretion of Avalonia and early Carboniferous accretion of the Armorican Terrane Assemblage (ATA) attached new continental material around the Bruno-Silesian Promontory (BSP). Palaeozoic faunal affinities and inherited isotopic signatures similar to those of Avalonia seen in the Istanbul block of NW Turkey, and in minor thrust slices in Moravia and Romania, suggest that easternmost Avalonia was severed, on collision with the BSP, and migrated east along the southern margin of the EEC. Likewise, the similarities to the ATA of the Balkan, Istranca, Sakarya and eastern Pontides blocks suggests that more easterly components of the ATA were detached at the BSP and migrated east. All the newly accreted blocks contain similar Neoproterozoic basement indicating a peri-Gondwanan origin; Palaeozoic plume-influenced metabasite geochemistry in the Bohemian Massif may explain their progressive separation from Gondwana before their accretion to the EEC. Inherited ages from Avalonia contain a 1.5 Ga ‘Rondonian’ component arguing for proximity to the Amazonian Craton at the end of the Neoproterozoic; Armorican terranes lack such a component, suggesting that they have closer affinities with the West African Craton. Models showing the former locations of these terranes and the larger continents from which they rifted, or later became attached to, must conform to both these constraints and those provided by palaeomagnetic data. In the late Neoproterozoic and Palaeozoic, these smaller terranes, some containing Neoproterozoic ophiolitic marginal basin and magmatic arc remnants, probably fringed the end-Proterozoic supercontinent as part of a ‘Pacific-type’ margin. When this margin fragmented, most resulting fragments accreted to the EEC.
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European Lithosphere Dynamics
Europe provides an outstanding field laboratory for studying lithospheric processes through time, for tracing tectonic evolution of crust and mantle from the present far back into the early Precambrian. Two things are particularly striking: the importance of plate tectonics during the Phanerozoic and through Protezoic into the Archaean, and the significance of tectonic inheritance, older structures and rheologies guiding the younger evolution.
'European Litosphere Dynamics' grew out of a major European Science Foundation programme, EUROPROBE, with participation of many hundreds of Earth Scientist from all over Europe. The many research activity focus on specific target areas and involved integration of geological, geophysical and geochemical methods. Defining surface-depth relationships was a prerequisite for interpretation of the processes, present and pass, responsible for the formation of the litosphere.
This Memoir addresses the major features of the European lithosphere and is aimed at giving the reader an overview of their development and growth during three billion years of Earth history.