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Geology, mineralogy and origin of Zhyrychi native copper deposit (North-Western Ukraine)

Emetz A., Piestrzyński A., Zagnitko V., Pryhodko L., Gaweł A.

Annales Societatis Geologorum Poloniae

2006

Vol. 76, No 3

297-314

The paper presents geological settings, resources and mineral composition of theore bodies of the Zhyrychi copper deposit found in the North- Western Ukraine at the end of the last century. The deposit is located in the Vendian basaltic flows and in traflow pyroclastics in central part of the Volhyn trappean province, originated in the Late Vendian during Torn quistrifting. The majority of copper is concentrated in native form and occurs as disseminated grains, veinlets and nuggets. Locally native siver, copper- sulphides (chalcosite, digenite, bornite and covellite) and cuprite replace native copper. The ore bodies are controlled by faulting and occur as stratabound, but are locally enriched in nuggets in tuffs and fissured zones in ba alts. Ag, Pd, Rh and Aucan also beeco nomically important. The major copperores were deposited to gether with prehnite- pumpellyite para genesis, originated in the succession: pumpellyite – prehnite (šnative copper) – laumontite (or wairakite) (šnative copper). The ore bodies were formed during cooling of the mineralforming hydrothermal system at the end of the Vendian volcanic activity. The syngenetic inter growths of native copper with prehnite, precipitated after pumpellyite, and homogenization temperature of fluid inclusions in later wairakite (210–335gradeC) indicate that the major deposi tion of native copper took place at 200–400gradeC. The following propylitization, smectitization and analcilization of thecountry rocks probably occurred during at tenuation of the hydrothermal activity after magmatism ceased. All these processes were accompanied by dissolution of copper ore and its redistribution with local enrichment in copper nuggets.

Geological framework of the Volhyn copper fields with a review of the Volhyn Flood Basalt Province (western margin of the East-European Craton)

Emetz A., Piestrzyński A., Zagnitko V.

Annales Societatis Geologorum Poloniae

2004

Vol. 74, No 3

257--265

Geological structure of the Volhyn Flood Basalt Province has been described. Hydrothermally altered and partly eroded Vendian lava flows and intraflow pyroclastics occur upon an area of about 350,000 km2 in Belarus, Poland, the Ukraine, and Moldova. They host important native Cu mineralization. The Vendian volcanism developed during four volcanic phases, producing lava and pyroclastics within the Tornquist rift system along the Teisseyre-Tornquist margin. During the last two phases, the Vendian rift was tectonically parted with crust melting. The major volcanic activity occurred in the part superimposed on the deepest part of the older Late Riphean mid-Baltica rift system, which developed across the Tornquist rift. The rifting finished with opening of the Tornquist Ocean. Actually, the Palaeozoic, Mesozoic, and (or) Cainozoic beds cover the trappean volcanic plateau. The Ratne and Rafalovka-Berestovets copper fields are situated in the central part of the Lukow-Ratne swell and along western border of the Ukrainian Shield, respectively. The ore-bearing basalts were partly eroded since the Devonian until the Late Cretaceous.