DILL, H. G. (1989): Metallogenetic and geodynamic evolution in the Central European Variscides. - A pre-well site study for the German Continental Deep Drilling Programme. - Ore Geology Review, 4: 279-304; Amsterdam

 

Abstract: In the central European Variscides (Czechoslovakia, F.R. of Germany, German Democratic Republic) numerous ore deposits of different size and origin are located in the Saxothuringian-Moldanubian border zone. These ore de­posits may be categorised into four different types: type I: stratabound; type II: thrustbound; type III: granite-bound; and type IV: unconformity-related. Plate tectonic concepts have only recently been applied to the geodynamic evo­lution of this part of the Variscides. In the Thuringian and Bavarian Facies, stratabound deposits - type I - ("mas­sive sulfides", carbonate-hosted Pb-Zn deposits ) evolved during the Cambrian and Early Ordovician in a continuously expanding rift basin. At its maximum extension a dismembered, immature "ophiolite sequence" with Ni-Cr-Cu dis­semination in meta-ultrabasic igneous rocks formed in the central European Variscides. Afterwards, an "extensional arc environment" with Cu-Fe-Zn sulfides came into existence along the central Saxonian lineament. This B-subduc­tion during the Middle to Late Ordovician reflects the change from a divergent to a convergent marginal basin. During the Devonian with the beginning of the A-subduction, stratabound and thrust-bound deposits formed by the pervasive shearing of Silurian metalliferous black shales (graptolite shale facies). As a result of distension deep-seated fault zones in Upper Devonian, relict basins were responsible for the exhalative hematite ores bound to basaltic rocks. Subsequently, thrust-bound (type II ) Sb, Au, and As ore mineralisation formed along axial plane thrust faults during the Early Carboniferous. Granite-related Sn, W, and U mineralisation (type III ) followed when Lower Carboniferous granites were intruded into that terrain, as a result of final plate collision. Ba-F and Pb-Zn vein-type deposits occur throughout the Lower Permian to Liassic (type IV). They are related to the Late Variscan unconformity resulting from peneplanation of the uplifted basement block.