Carlin-like Pyrite in Orogenic Copper-Gold Deposits in the Eastern Alp

The Carlin-type gold (CTG) mineralization has been known in north-central Nevada since the early 1960s, but was until quite recently assumed to be a Nevadan phenomenon. The model to form the gold containing pyrite in these deposits requires an iron-rich carbonate host rock, which is thought to release its iron during dissolution by an acidic fluid carrying gold, arsenic, and sulfur (Muntean et al., 2011). The subsequent pyrite is thought to grows at the at the expense of the hydrogen-sulfide complex and therefore causes the precipitation of gold.

We will discuss the new model for gold incorporation into pyrite (Gopon et al., 2024), how it links to the occurrence of gold and arsenic containing pyrite from orogenic deposits in the Eastern Alps (Goebel, 2024; Hiller, 2024; Dunkel et al., 2025). These orogenic pyrites appear near identical to pyrite from CTG deposits, despite having none of the required components for gold-arsenic rich pyrite formation from the Muntean model. Do we therefore need to question this model, or are there multiple ways to generate identical pyrite microstructures/geochemistry?

Our works suggest that a more universal model for Au-As rich pyrite is needed, and one that can explain the observed trends in pyrite geochemistry and gold remobilization. In the orogenic deposits in the Alps, we see amble evidence for native gold associated with pyrite, suggesting a secondary remobilization of native gold which was previously hosted in pyrite. In these orogenic deposits, this process appears to lead to an enrichment along the mineralization, which forms the high-grade native gold containing quartz veins for which these districts are famous for.

References:

Dunkel, F. et al., 2025, Precious and critical metal potential of historic Cu-Au-As mine waste in Spielberg, Austria, in Proceesing of the Annual European Geosciences Union Meeting, Vienna.

Goebel, E., 2024, Sulfide Geochemistry of the Hohen Tauern Historic Gold Districts (Austria): Montanuniversitat Leoben.

Gopon, P., Sack, P., Pinet, N., Douglas, J.O., Jenkins, B.M., Johnson, B., Penny, E., Moody, M.P., and Robb, L., 2024, Revealing Yukon’s hidden treasure: an atomic-scale investigation of Carlin-type gold mineralization in the Nadaleen Trend, Canada: Mineralium Deposita, v. 60, p. 937–953

Hiller, J., 2024, A green future from a contentious past: Gold and critical metals in a historic arsenic mining district Straßegg (Styria) [Masters Thesis]: Montanuniversitat Leoben.

Muntean, J.L., Cline, J.S., Simon, A.C., and Longo, A.A., 2011, Magmatic–hydrothermal origin of Nevada’s Carlin-type gold deposits: Nature Geoscience, v. 4, p. 122–127