Geochemical and volcanological documentation of temporary exposures of Ordovician volcanites during construction of the subway at Praha-Vokovice
2013
Abstract
Ordovician volcanic rocks exposed at the temporary exposures excavated during the construction of the subway line A at Praha-Cerveny Vrch comprise subaerial lava flow, deposits of scoria comprising fallout and possibly also pyroclastic flow deposits. They are all enriched in incompatible elements, resembling within-plate alkali basalts to within-plate tholeiites.
Spiderplots normalized by NMORB point to their affinity to an OIB magmatic reservoir, yet with a significant role for crustal contamination. The geotectonic setting most probably corresponded to an attenuated crust, such as shallow-marine rift basin with Cadomian continental basement.