Organic and inorganic geochemistry of gold mineralisation at the Zloty Stok, Southwest Poland

Abstract

Inorganic and organic geochemical data obtained from contact-metasomatic and skarn-like mineralisation and associated country rocks from the Zloty Stok Au-As deposit in Southwest Poland have been studied. Magnetite-rich calcite-dolomite marbles have the highest total organic carbon content of the rocks studied. Organic matter consists of solid bitumen, with a minor extractable fraction composed mainly of low molecular weight aromatics. There are positive correlations between organic matter and Fe 2 O 3 and MgO content, suggesting remobilisation of organic matter by the hydrothermal fluids during serpentinisation processes. Results of the organic geochemical and isotope studies suggest that the hydrocarbons were formed by thermal and later hydrothermal alteration of indigenous organic matter. The ranges of d 34 S values of sulphides show that in Au-rich arsenopyrite and pyrrhotite, most of the sulphur may have originated from a magmatic source. However, some of results indicate a contribution from isotopically heavier sulphur, most probably associated with fluids derived from the metamorphic sedimentary environment. Rare earth element patterns of the mineralised samples point to a granitic source of the studied orebodies.

The Occurrence of Tellurium and Bismuth in the Gold-Bearing Polymetallic Sulfide Ores in the Sudetes (Sw Poland)

“…Przedmiotem eksploatacji by³y g³ównie rudy arsenopirytowo-löllingitowe oraz magnetytowo-pirotynowe wystêpuj¹ce w postaci mniej lub bardziej masywnych impregnacji, ¿y³ czy lamin w ska³ach diopsydowo--tremolitowych, czarnych serpentynitach czy marmurach dolomitycznych (np. Kowalski 1963Kowalski , 1969Muszer 1997, Mikulski 1996bMikulski i Speczik 2008;Muszer 2011). Mineralizacja z³otonooena w Bardzie OEl¹skim rozpozna zosta³a w strefie zachodniego kontaktu apofizy Grañca-Barda intruzji k³odzko-z³otostockiej ze ska³ami jednostki bardzkiej (Mikulski 1998).…”

The auriferous ore mineralization and its zonal distribution around the Variscan Kłodzko-Złoty Stok granitoid pluton in the Sudetes (SW Poland) – an overview

“…3F, H). The vein-type ore min er ali sa tion is less abun dant and oc curs lo cally in quartz and peg ma tite veins (Mikulski and Speczik, 2008).…”

“…Ar seno py rite is gen er ally youn ger than löllingite, which to gether with com monly ori ented intergrowths of chal co py rite in pyrrhotite may sug gest high (>400°C) tem per a tures of metasomatic pro cesses dur ing the for ma tion of the pyrrhotite-as so ci ated min er als (Mikulski, 1996a). Mag netite-rich min er ali sa tion in dolomitic mar bles is char ac ter ized by in creased amounts of or ganic ma te rial, while in the sam ples with rich ar senic ore the con tent of or ganic mat ter is lower (Mikulski and Speczik, 2008). At the Z³oty Stok de posit the main mag ne tite gen er a tion oc curs to gether with pyrrhotite.…”

“…6B), Y (cc = 0.87; n = 29) and weaker with V (cc = 0.44; n = 50), Cd (cc = 0.35; n = 50), SiO 2 (cc = 0.35; n = 65) and MgO (cc = 0.22; n = 29). Re cent stud ies in the Z³oty Stok de posit revealed that the con tent of or ganic car bon (TOC -To tal Or ganic Car bon) de creased in zones of gold en rich ment (Mikulski and Speczik, 2008). Sim i lar re la tion ship was also re ported from other de pos its (Gize, 1999).…”

“…7A, B) from do lo mite mar bles with mag ne tite-rich ores are more char ac ter is tic of hydro ther mal flu ids. These val ues were ex plained as a re sult of com bined in ter ac tion of sev eral pro cesses, in clud ing dolomitisation, serpentinitisation, de-dolomitisation and iso tope ex change re ac tions be tween min er als and flu ids, due to thermal and sub se quent hy dro ther mal in flu ence of Variscan granitoids with par tial ox i da tion and mo bi li sa tion of or ganic matter (Mikulski and Speczik, 2008). More over, an in flux of freshwa ter dur ing the later phases of skarn for ma tion can not be excluded, as min er al ised sam ples are re lated to a frac ture zone where the in flu ence of such flu ids is al ways pos si ble.…”