Acta Musei Moraviae

Pyromorphite from Pb–Zn ore deposit at Nová Ves near Rýmařov (Jeseníky Mts., Czech Republic)

Pyromorphite samples from weathering zone of the vein deposit Nová Ves at Rýmařov are identified and studied with respect to their origin. Pyromorphite was found in assemblage with limonite and plumbogumite. Pyromorphihe crystals have zonality, lighter zones (in BSE image) with higher Pb alternate darker zones with higher Ca. Changes in fluids composition and pH during crystallization of pyromorphite are in connection with described zonality. Two independent substitution in pyromorphite were detected: pyromorphite – mimetite (P–As) and pyromorphite – apatite (Pb–Ca). Second type of pyromorphite zonality is represented by changing of compact and porous zones in crystal. It can be in connection with partial dissolution of pyromorphite crystals or with rapid grow stages of crystals. Source of Pb in supergeneous waters (solutions) is galena and source of Ca are vein carbonates, pyrite is primary mineral for traces of As. Phosphorus in water solutions is derived probably from phyllites. The similar situation is described from Zlaté Hory sulphidic deposit.