Late palaeozoic and early mesozoic hydrothermal events inthe northern Rhenish Massif results from fluid inclusion analyses and cathodoluminescence investigations

Abstract

In the Devonian reef limestones of the Velbert Anticline and the Remscheid-Altena Anticline (northern Rhenish Massif, western Germany), several pre- to syntectonic Variscan phases of mineral formation and five post-Variscan hydrothermal events are recognised. They are subdivided using paragenetic sequences and characterised by cathodoluminescence (CL) investigations and fluid inclusion analyses. The carbonate minerals have a complex history of alteration by younger hydrothermal activity, while most of the quartz crystals show a well preserved sectorial and growth zonation. Fluid inclusions were analyzed in the 2nd and 3rd hydrothermal quartz generation. Low eutectic temperatures (− 80 °C) indicate Ca Na(Mg) Cl solutions. The melting temperatures of the ice indicate a solution with very high salinity, which is thought to have its origin in the dissolution of Permian evaporites in the Niederrhein area or in evaporated seawater. The homogenisation temperatures are between 90–100 and 120–140 °C, respectively.