Spatial and Temporal Evolution of the Freiberg Epithermal Ag-Pb-Zn District, Germany

Abstract

The Freiberg district hosts one of the largest series of epithermal polymetallic vein deposits in Europe. The availability of a systematic collection of historical samples provides an excellent opportunity to study the anatomy of these epithermal systems. Detailed petrographic investigations, geochemical analyses, and fluid inclusion studies were conducted on several vertical profiles within the Freiberg district to decipher mineralogical and geochemical zoning patterns. Six distinctive mineral associations have been recognized within the Freiberg epithermal veins; sphalerite-pyrite-quartz and galena-quartz±carbonate associations are most abundant in the central sector, as well as in the deepest sections of veins on the periphery of the district. A high-grade sphalerite-Ag-sulfides-carbonate association occurs laterally between the central and peripheral sectors and at intermediate depth in veins on the periphery. Shallow and peripheral zones are dominated by an exceptionally Ag-rich Ag-sulfides-quartz association, whereas the shallowest veins locally comprise Ag-poor stibnite-quartz and quartz-carbonate associations. Fluid inclusion assemblages returned low salinities (<6.0 wt % NaCl equiv), and homogenization temperatures successively decrease from ~320°C associated with the proximal and deep sphalerite-pyrite-quartz association, to ~170°C related to the distal and shallow Ag-sulfides-quartz association. The architecture of the Freiberg district is related to the temporal and spatial evolution of magmatic-hydrothermal fluid systems, including boiling and concomitant cooling, as well as CO2 loss. Constraints on the paleodepth indicate that the veins formed between 200 and 1,800 m below the paleowater table. High-grade Ag ore occurs over a vertical interval of at least 500 m and is bracketed by shallower stibnite-quartz and barren quartz, and deeper base metal-sulfide-quartz zones.

Timing of magmatic-hydrothermal activity in the Variscan Orogenic Belt: LA-ICP-MS U–Pb geochronology of skarn-related garnet from the Schwarzenberg District, Erzgebirge

“…In contrast, a younger stage of skarn formation in the Erzgebirge was dated to ~ 308.1 ± 3.6 to 295.5 ± 4.4 Ma, coinciding with post-collisional magmatism (Burisch et al 2019b). These ages overlap within error with the 276 ± 16 Ma epithermal Ag-Pb-Zn-veins of the Freiberg District that have tentatively been related to post-collisional magmatic activity (Bauer et al 2019b;Burisch et al 2019a;Ostendorf et al 2019;Swinkels et al 2021) and that represent the youngest record of magmatic-hydrothermal activity in the Erzgebirge.…”

The Spatial and Temporal Evolution of the Sadisdorf Li-Sn-(W-Cu) Magmatic-Hydrothermal Greisen and Vein System, Eastern Erzgebirge, Germany

“…The Erzgebirge/Krušné hory region (Fig. 1A) is a classic metallogenic province that hosts late-Paleozoic magmatichydrothermal systems such as greisen (Štemprok, 1967;Baumann and Tischendorf, 1976), skarn (Hösel, 2003;Burisch et al, 2019;Reinhardt et al, 2021), and epithermal vein-type mineralization (Swinkels et al, 2021) as well as Mesozoic hydrothermal five-element-and fluorite-barite-vein systems (Kuschka, 1972;Guilcher et al, 2021;Haschke et al, 2021;Burisch et al, 2022). The Erzgebirge comprises a series of metamorphic nappes that developed during the Variscan orogeny in Central Europe (i.e., the collision of Laurussia and Gondwana; Kroner et al, 2007;Linnemann and Romer, 2010).…”

The Occurrence and Chemical Composition of Bismuth-Bearing Minerals in the Niuxingba-Liumukeng Ag-Pb-Zn Deposit, Jiangxi Province, South China

“…The epithermal deposit closely related to silver, lead, and zinc mineralization is an important type of deposit [24][25][26][27][28][29][30]. In recent years, several studies concluded that bismuth and silver could coexist in many silver deposits, and bismuth may promote the precipitation of silver, providing a new insight into the silver mineralization [2,[31][32][33].…”