Fig. 2. Polyelement GCF of ore elements. Dukat deposit. Central Dukat area * . 1–17 – geochemical associations of elements: 1 – 4 – mainly silver: 1 – Ag(30/300) As (600/300) Sb(500/250) Au(0.25/50) Pb(330/33) Zn(300/30) Mn(10000)/20) Cu(400/20), 2 – Ag(20/200) Au(03/60) As(34/17) Pb(150

Fig. 4. Polyelement GCF of ore elements. Dukat deposit. Smelyi area. 1–6 – geochemical association of elements: 1 , 2 – supraore: 1 – As(30/15)Ag(1.5/15), 2 – As(160/80) Ag(6/60) Sb(30/15) Hg(0.4/8); 3 , 4 – ore: 3 – Ag(70/700) As(140/70) Au(0.2/40) Sb(20/10) Mn(3000/6), 4 – Ag(9

andesites ( 4 ), rhyolites ( 5 ) of the Kakhovka and Shorokhovo formations; 6, 7, subvolcanic high-K ( 6 ) and K–Na ( 7 ) leucocratic rocks: magnophyric ( a ), fluidal and aphyric ( b ); 8, subvolcanic gabbroids; 9, orebodies of the Dukat deposit; 10, 11 , faults: concealed, in the E–W striking Buyunda

Fig. 10. Corroded proustite grain in assemblage with iron hydroxides and decomposed quartz and feldspar grains in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit. a , BSE image; b – d , X-ray images.

Fig. 9. Aggregate of iron hydroxides and relict acanthite–sternbergite segregations in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit. BSE image. 1–10, points of determination of the element contents presented in Table 11 .

Fig. 1. Schematic position of the study area (I) and ore objects. Ores: gold-silver : 1 — Dukat deposit, 2 — its northern flank, Smely site; tin-silver : 3 — Malokenskoe deposit, 4 — Final’noe ore occurrence; silver-polymetallic : deposits: 5 — Mechta, 6 — Tidit.

Fig. 6. Corroded acanthite grains in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit. a , BSE image; b – d , X-ray images. Part a : 1–15, points of determination of the element contents presented in Table 8 .

Fig. 4. Fine-grained gold (electrum) in the loose sediments of streams draining Au–Ag zones at the Dukat deposit. a , BSE image; b , c , X-ray images. Part a : 1–15, points of determination of the element contents presented in Table 3 .

Fig. 3. Parameters of mineralization at Ag deposits, obtained by study of fluid inclusions. Ore cluster: I — Bazardara (Pamir), II — Mangazeya, III — Deputatsky; IV — Dukat deposit. Hatched area corresponds to the parameters of formation of Ag-ore parageneses. Isolines show the calculated total

Fig. 12. Aggregate of kidney-shaped pitticite segregations with a crust of iron hydroxides in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit. a , BSE image; b , c , X-ray images. Panel a : 1–7, points of determination of the element contents shown in Table

Fig. 11. Mixture of phases (iron and arsenic (?) oxides and hydroxides, scorodite (?) (secondary mineral of As)) in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit. a , BSE image; b – d , X-ray images. Part a : 1–10, points of determination of the element

Fig. 7. Colloform-zoned aggregate acanthite–sternbergite(?) + iron hydroxides, formed by epigenetic processes, in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit. a , BSE image; b – d , X-ray images. Part a : 1–10, points of determination of the element

Fig. 15. Cu–Zn intermetallic (gray) with ultradispersed segregations of Cu–Fe compounds (white) in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit. a , BSE image; b , c , X-ray images. Part a : 1–6, points of determination of the element contents presented

Fig. 5. Corroded grain of acanthite + iron oxides ( a ), formed by epigenetic processes, in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit, and an enlarged fragment of a preserved part of the acanthite crystal ( b ). BSE image. Part b : 1–14, points

Fig. 8. Ore minerals in the loose sediments of the streams draining the Au–Ag zones at the Dukat deposit: a , Acanthite inclusions (white) in a magnetite grain (gray); b , acanthite (white) with a pyrite inclusion (gray); c , intergrowth of acanthite (white) with pyrite (gray); d , sphalerite

Fig. 2. Geological sketch map of the Dukat Au–Ag deposit. Compiled after ( Konstantinov et al., 1998 ): 1 , loose Quaternary sediments (Q); 2 , rhyolites and rhyodacites, Shorokh Formation (K 2 šr); 3 , andesites and andesite-basalts, Kakhovka Formation (K 1-2 kh); 4 , conglomerates