Hydrothermal Karst Phenomena as a Factor in the Formation of Mississippi Valley-Type Deposits

Comparison of the Cracow-Silesian mississippi valley-type district, southern Poland, with mississippi valley-type districts in North America

“…In the C-S district, karst breccias are important hosts for a significant part of the ore. These karst breccias are widely thought to have been produced entirely by the ore fluids and that ore deposition, dissolution, and brecciation were essentially simultaneous (Bogacz et al,1970;Bogacz et al, 1973;Sass-Gustkiewicz, 1975a;Sass-Gustkiewicz, 1975b;Dzulynski and Sass-Gustkiewicz, 1985). Field observations are consistent in part with the previous studies and indicate that a significant amount of dissolution and brecciation did occur during ore deposition.…”

“…and replacement of preexisting karst breccias by the ore-forming fluids. Many ore textures presented as support for ore-stage hydrothermal brecciation (Bogacz et al,1970;Bogacz et al, 1973;Sass-Gustkiewicz, 1975a;Sass-Gustkiewicz, 1975b;Dzulynski and Sass-Gustkiewicz, 1985) can be interpreted as dominantly replacement textures that mimic the pre-ore breccias (fabric-conservative replacement). Karst breccias are just one of several rock textures that have been selectively mineralized and replaced by the ore fluid.…”

“…Sulfides also form a variety of "dripstones-like" or "speleothem" stalactites ( Fig. 12D), stalagmites, curtains, and drapestones (Bogacz et al, 1970;Sass-Gustkiewicz, 1985;Sobczynski and Szuwarzynski, 1975;Motyka and Szuwarzynski, 1989) Typically these features are composed of marcasite but in the Trzebionka mine, the dripstone-like forms are also composed of sphalerite and occasionally galena. Motyka and Szuwarzynski (1989) describe these drip-stone like features as usually forming "stalactites" on the top of cavities and open spaces; stalagmites are less abundant and similar forms of sulfide pipes occur on the sides of cavities.…”

Geology and Geochemistry of the Reocin Zinc-Lead Deposit, Basque-Cantabrian Basin, Northern Spain

“…However, Velasco et al (2000) confirmed the epigenetic origin by demonstrating that karstification, dolomitization, and ore precipitation were contemporaneous and linked to the deposition of internal sediments, produced by the circulating hydrothermal fluids. The importance of hydrothermal karstification (Dzulynski and Sass-Gustkiewicz, 1985;Sangster, 1988) associated with the circulation of metal-bearing fluids and the deposition of dolomite sands infilling open spaces and solution-enhanced cavities are consistent with Mississippi Valley-type ore deposition in carbonate rocks (Sass-Gustkiewicz, 1996;Bouabdellah et al, 1996). Additional geologic, mineralogic, and geochemical observations and data are presented below 1372 VELASCO ET AL.…”

Diagenesis and mineralization processes in Devonian carbonate rocks of the Siding-Gudan lead-zinc mineral subdistrict, Guangxi, Southwest China

“…In the case of the strata-bound Siding lead-zinc ore bodies, the Devonian carbonate rocks (D 2d ) were mineralized in situ along the major faults whereas the iron sulfide ore body of Gudan is placed in between the Lower Cambrian clastics and the overlying Upper Devonian ( Figure 5), where hydrothermal karstification occurred (Dzulynski and Sass-Gustkiewicz, 1985).…”