Metallogenesis and Tectonics of the Russian Far East, Alaska, and ...

Rodnikovoe Au Quartz-Adularia Epithermal Vein Deposit
The Rodnikovoe Au quartz-adularia epithermal vein deposit (1.D. Shchepot'ev, 1989; D. Petrenko, written commun.,
1991; Petrenko, 1999) consists of a major vein and related quartz and quartz-carbonate veins and veinlets which cut the apical part
of a gabbro-diorite intrusion. In addition to gold, the veins and veinlets contain goldfieldite, silver sulfosalts, and argentite. Gold
fineness is 400 to 600. Alteration includes propylitic (chlorite-carbonate and epidote-chlorite facies), kaolinitic, quartz-hydromica
alteration with montmorillonite, and silicic with quartz and pyrite. The altered rocks are laterally zoned. The ore occurs in a
complex vein system with several funnel-shaped ore shoots which narrow with depth. The shoots dip 30-50" south. The vertical
extent of mineralization is less than 150 m. High Au concentrations (25-30 g/t Au) occur in upper levels of ore bodies. The quartz-
adularia veins are Late Miocene with K-Ar ages of approximately 0.9 to 1.1 Ma (Takahashi and others, 2001). The deposit is of
medium size. Average grades range up to 1 1.3 g/t Au and 40-50 g/t Ag. The estimated reserves are 40 tonnes gold and 356 tonnes
silver with an average grade of 1 1.0 g/t Au and 98.0 g/t Ag.
Origin of and Tectonic Controls for
East Kamchatka Metallogenic Belt
The Central Kamchatka volcanic belt which hosts the East Kamchatka metallogenic belt consists chiefly of Eocene to
Quaternary thick, gently dipping andesite, dacite, and rhyolite strata which are interlayered with sandstone, siltstone, and
conglomerate, and widespread large ignimbrite fields. Shallow-marine deposits predominate in the lower part and nonmarine
deposits predominate in the upper part. The formation of the belt culminated with eruptions of Pliocene to Quaternary plateau
basalts which are associated with large composite cone volcanoes. The volcanic belt is interpreted as a major post-accretionary
continental-margin arc which is tectonically linked to the Kuril-Kamchatka accretionary wedge and subduction zone complex (fig.
125) (Nokleberg and others, 1994c, 1997~).
Central Kamchatka Metallogenic Belt of
Au-Ag Epithermal and Porphyry Cu-Mo
Deposits (Belt CK) Kamchatka Peninsula
The Central Kamchatka metallogenic belt of Au-Ag epithermal vein and porphyry Cu-Mo deposits (fig. 125; tables 3,4)
occurs along the length of the Kamchatka Peninsula. The deposits are hosted in the Central Kamchatka volcanic and sedimentary
basin of Oligocene to Holocene age (Nokleberg and others, 1994c, 1997~). The significant deposits in the belt are (table 4)
(Nokleberg and others 1997a, b, 1998): Au-Ag epithermal vein deposits at Aginskoe (Aga), Baran'evskoe, Oganchinskoe,
Ozernovskoe, Sukharikovskie Grebni, Tutkhlivayam, and Zolotoi; a porphyry Cu-Mo deposit at Krasnogorskoe; and a volcanichosted
Hg deposit at Chempura.
The Au-Ag epithermal vein deposits are interpreted as formlng mainly during two stages in the Miocene. (1) In the early
Miocene (22 to 14 Ma), during eruption of mainly felsic volcanlc rocks, low sulfide, Au-Ag deposits, as at Ozernovskoe and
Tutkhlivayam, with high Te contents, formed during construction of composite cone volcanoes and associated hypabyssal
intrusions. At the same time, sulfide Au deposits, as at Olgakanskoe, with high Cu, Pb, and Zn contents, formed in association
with intermediate intrusions. However some of these deposits may have formed during the Late Eocene to Oligocene. And (2) in
the late Miocene (12 to 5 Ma), in the final stages of Miocene volcanism, andesitic and basaltic alterations. Au @ Ag) epithermal
vein deposits formed in association with small hypabyssal bodies and dikes, as at Agmskoe, Sukharikovskie Grebni, and
Baran'evskoe deposits and some ore bodies of Tutkhlivayam deposit. These deposits consist mainly of gold and minor sulfide
minerals in quartz-adularia veins. In the middle and northern parts of the belt, Hg deposits, as at Chempura, and Au and Au-Ag
epithermal vein deposits occur in late Miocene hypabyssal bodies and dikes.
Porphyry Mo, Cu, and Cu-Mo deposlts in the southern part of the belt occur in Miocene subalkaline granite porphyry and
porphyritic diorite. These granitoid plutons intrude areas underlain by the eastern part of the Sredinny-Kamchatka metamorphic
terrane. These deposits, as at Kirganik, Krasnogorskoe, and Malakhitovoe, are small to medium-size, and occur mainly in
stockworks and in long fracture zones in both intrusions and adjacent metamorphic rocks. The major ore minerals are pyrite,
chalcopyrite, and molybdenite. Molybdenite contains high amounts up to 600 g/t rhenium.
Ozernovskoe Au-Ag Epithermal Vein Deposit
The large Ozernovskoe Au-Ag epithermal vein deposit (Shchepot'ev, 1989) consists of Au-bearing quartz-adularia veins
along with Cu-Mo, realgar-orpirnent, and Au-Ag deposits. The Au-Ag deposits occurs in veinlets and disseminations and is
superimposed on various facies of hydrothermally-altered rocks. Ore formed in fracture-filling veins and veinlets, and as
metasomatic replacement of earlier aggregates. At least four stages of mineralization are recognized: (1) gold-goldfieldite-quartz
(fineness of 933-938); (2) tellurium-silvanite-goldfieldite-kaolinite-quartz gold 945 fine; (3) gold-hessite-hydromlca-quartz (gold
894 fine); and (4) gold-adularia-hydromica-quartz (gold 643 to 679 fine). Host rocks exhibit several types of alteration, mainly
propylitization and silicification. Argillite, displaying quartz-sericite, quartz-kaolinite, and quartz-montmorillonite-hydromica
facies alteration, occurs in the central part of the ore field, near the main volcanic vent. Altered rocks consist of quartz and pyrite-
alunite-kaolinite-quartz assemblages which form linear bodies up to 100 m thick along the fault zones. The largest ore bodies