PGE in ultramafic rocks of the hidden ophiolite complex near Svitavy, Bohemian Massif

Abstract

Anomalous concentrations of platinum-group elements (PGE) Pd - up to 281 ppb, Pt - up to 110 ppb, Ir - up to 7.4 ppb, Ru - up to 19.8 ppb, Rh - up to 8.4 ppb and Au (up to 18.5 ppb) have been detected in low Ni-Cu (Cr) mineralized pyroxenite and serpentinite recovered from the HSV-1 structural borehole at Svitavy. Based on geological and geotectonic position and geochemical data these rocks hidden under Cretaceous sediments represent most likely continuation of the Letovice ophiolite complex. Maximum Ni, Cu and Cr values reach 0.67, 0.11 and 0.35 wt.%, respectively and abundant spinels (Cr-spinel, magnesiochromite, chromite) and magnetite with minor sulphides (millerite and chalcopyrite) were identified as major ore bearing minerals in the most richest PGE sample. No discrete PGE phases were identified.