The Kapelka Ag-Au prospect is located in the Western Chukchi Peninsula, Russia. The mineralization is hosted by Upper Cretaceous volcanic rocks of the Okhotsk-Chukchi Volcanic Belt (OChVB). Wallrock alteration and ore bodies are associated with NE and NNE trending faults.The LS and base metal types of mineralization are predominant at the Kapelka prospect. Ore bodies occur as stockwork and veinlet systems. Major alteration types are propylitic, argillic and secondary quartzite. High grades of main components were determined in ore samples: 1.5% Ag, 12% Pb, 2.2% Cu, 0.8% Zn and 27 ppm Au; gold silver ratio is from 1: 100 to 1: 3500. The anomalous geochemical field is widespread. The composition of secondary halos is corresponding to the one of primary ore.Propylites are composed of epidote, chlorite, K-feldspar, quartz. The main minerals of argillic rocks are tosudite, montmorillonite, dickite and quartz. Propylitic and argillic rocks were formed at the temperature of 330-365 and 110-300 degrees C. respectively (the Cathelineau thermometer [1]). Gangue minerals include quartz, adularia, sericite and others. Ore minerals are pyrite, arsenopyrite, galena, sphalerite, chalcopyrite, bornite, electrum, polybasite-pearceite, acanthite and tetrahedrite-tennantite. Native silver, acanthite, anilite, brochantite, anglesite, cerussite, malachite, azurite and wulfenite represent supergeneous assemblage. Homogenization temperatures of fluid inclusions vary from 167 to 353 degrees C, salinity is within the range of 0.2-1.4 wt. % NaCl equiv. Pressure estimated for fluid boiling at the temperature of 353 degrees C is 16MPa corresponding to the ore formation depth of 0.6 km.According to geology, wallrock alteration and composition of geochemical anomalies, the closest analogue of Kapelka is the Zhilny prospect nearby the large Au-Ag epithermal Valunistoye deposit, the Eastern Chukchi Peninsula. Future exploration will clarify the parameters of the ore bodies and economic prospects of Kapelka.

The giant Peschanka porphyry Cu-Au-Mo deposit is related to the Baimka ore zone located in front part of the Chukotka-Okhotka magmatic Andean-type belt. The deposit is hosted by the Egdigkich monzodiorite intrusion of Early Cretaceous age (142 Ma), and by stocks and dikes of monzodiorite porphyry, quartz monzodiorite porphyry, and syenite-porphyry which intrude the Egdigkich stock. A central core of potassic alteration surrounded by propylitic alteration, whereas late, linear phyllic alteration zones and lenses with NW, NE, and east-west orientations host stockwork veining. Quartz and quartz-sulfide veinlets and veins are located in the core of the deposit. In general, ore minerals were deposited after the hydrothermal formation of the alteration assemblages. Vein-disseminated sulfide mineralization forms an overall north-south oriented, linear stockwork zone of about 7000 m by 700-1500 m in size. Based on drilling data, economic mineralization extends to at least 700 m depth. Copper grades increase at depth in the eastern part of the orebody, from 0.3-0.7% to 1-8.5%. Based on geophysical data, hydrothermal alteration and sulfide mineralization extend more than 1 km at depth. Blind ore bodies are likely to be found. Currently, mineral resources include 1517 Mt of ore containing 7.9 Mt of copper, 450 t of gold at a cut-off of 0.4% Cu equivalent. Further exploration may increase of resources to at least 10Mt of copper. The Peschanka deposit is interpreted as a linear extension structure formed by right-lateral movement along the Baimka regional fault. A strike-slip fault model of the deposit explains the large size and depth extent of the mineralization.