Argentopentlandite from barite vein in Zagórze Śląskie, Lower Silesia; a first occurrence in Poland

Adam Piestrzyński,Krzysztof Kowalik

doi:10.1515/mipo-2015-0001

Abstract

Abstract Argentopentlandite has been found in samples collected on the dump of the Michael mine, an old silver mine in Zagórze Śląskie in the northern part of the Góry Sowie mountains. Though argentopentlandite is not a very common mineral, it is well known from high-temperature hydrothermal veins and from Ni-Cu deposits hosted in ultramafic rocks also containing platinum-group minerals. The argentopentlandite has been recognized in a sulphide nest in association with pyrrhotite and chalcopyrite in massive barite. In comparison to other occurrences (see Table 2), this mineral is characterized by a low Ni content (ave. 16.02wt% - EDS; 16.43wt% - WDS), a lack of cobalt and a relatively high copper content (ave. 2.13wt% - EDS; 1.55wt% - WDS). Based on these data, it can be concluded that the argentopentlandite, and the associated sulphides, were precipitated from hydrothermal fluids shortly after barite, the major vein constituent. As the optical properties of the argentopentlandite in reflected light are rather similar to those of bornite, it can be overlooked during routine observations. Thus, argentopentlandite or associated ore mineralization may also occur in other barite veins in the area.

Highlights

Argentopentlandite has been found in samples collected on the dump of the Michael mine, an old silver mine in Zagórze Śląskie in the northern part of the Góry Sowie mountains
Though argentopentlandite is not a very common mineral, it is well known from high-temperature hydrothermal veins and from Ni-Cu deposits hosted in ultramafic rocks containing platinum-group minerals
The argentopentlandite has been found in a barite-sulphide vein in the Góry Sowie mountains where, at least since Medieval times up to the beginning of the twentieth century, barite-sulphide veins were extracted for silver (Mączka, Stysz 2006)

Summary

Introduction

It was classified in the pentlandite group (Anthony et al 1990) though some mineralogists (Scott, Gasparrini 1973; Morales-Ruano, Hach-Ali 1996) have described it as a separate phase. It occurs in association with pyrrhotite, chalcopyrite, pentlandite and cubanite (Anthony et al 1990) as well as with starshaped sphalerite and mackinawite (Vavtar 1995; Kerestedjian, Bonev 2001). The new occurrence of argentopentlandite in hydrothermal veins changes our knowledge of their geochemistry and shows the importance of re-examining other barite occurrences to augment the fragmentary data noticed by Kowalski (1976) using modern laboratory techniques as has been done in other old mining sites in Lower Silesia (Piestrzyński 2005; Mochnacka et al 2009; Mochnacka et al 2012)

Methods

Outline geology

Findings

Conclusions