Ered in the Framework of the Magnetite-Series/ Ilmenite-Series Concept

RESOURCE GEOLOGY, 46(5), 267•`277,1996

Gold Deposits and Their ƒÂ34S Ratios of the Sikhote-Alin, Russia A Comparative Study with Those of the Sanyo Belt of Japan

Shunso ISHIIIARA*, V. V. IVANOV** and Vladimir RATKIN**

Abstract: In Sikhote Alin, mesothermal gold deposits are mostly associated with small Cretaceous intrusives and epithermal

deposits with Paleogene volcanic rocks. They are mostly quartz vein or veinlet types, but some occur in faulted sheared zone.

Common alteration minerals are quartz, sericite, carbonates and chlorite. Tourmaline and fluorite are rarely present. Native

gold and electrum occur associated mostly with chalcopyrite, pyrite, galena and sphalerite, and less commonly with arsenopyrite and other sulfides. Pyrrhotite is present in some places. Epithermal ores are rich in different Ag minerals. Adularia is not

uncommon in these ore deposits; thus, they are generally low sulfidation type. ƒÂ34S of these ore minerals vary from -9 .3 to 5.1 permil, but nagative values are predominant, indicating that ilmenite-

series granitoids are present much more than magnetite-series graitoids in the Sikhote Alin. Late Cretaceous mesothermal

deposits have wider variation in the S34S values than Paleogene epithermal deposits. In the largest Mnogovershinnoe epither-

mal deposits, sulfides from Au-bearing ores (average -5.4•ñ) are 3.6 permil lower than those of Au-free ores. Because of

scarcity of positive ƒÂ34S values, the paired ƒÂ34S values of the Inner Zone of Southwest Japan are not observed in the Sikhote

Alin side. Late Cretaceous granitic magmatisms and mineralizations in the Sikhote Alin have some similarity to those of the Sanyo

Belt, but gold deposits are much abundant in the Sikhote Alin side, and are quite different from those of the Gyeongsang basin in

Korea and Fujian coastal province in China.

ered in the framework of the magnetite-series/ ilmenite-series concept. The sulfur isotopic ratios 1. Introduction were measured on sulfides of the gold deposits The Western Pacific rim is characterized, unlike and compare them to those of the Inner Zone of the eastern Pacific rim, by abundance of marginal Southwest Japan, which may have been split-off basins, which may have been formed by spreading part of the continental margin. of continental margin. The latest opening period of 2. Outline of Geology the Japan Sea may be 21 Ma ago; Japanese Islands drifted southeastwards (HORIKOSHI, 1990). The Sikhote Alin is located to the east of Burea and reconstruction before the period may be only possi- Khanka massifs of Precambrian continental mar- ble by comparative studies on the land geology of gins, which are composed of accretional wedges the continental margin and the Japanese Islands. of Paleozoic and Mesozoic ages from west to east. Such.studies have been made preliminary on Sri de- These sedimentary rocks are divided into four posits (ISHIHARA,1980) and magnetic susceptibility major terranes (KHANCHUK,1993) as follows; (1) of the granitoids (SATO et al., 1993a,b; ROMANOVSKY Jurassic accretionary terranes with fragments of et al., 1995). Devonian to Triassic oceanic crust; (2) Neocomi- In this paper, gold deposits of the Sikhote Alin an accretionary terranes with fragments of Devon- are briefly described for the first time in the west- ian to Jurassic oceanic crust; (3) Turbidite basin ern journal, and their metallogeneses are consid- deposits derived from the Early Cretaceous continental slope and fun; (4) Mid-Cretaceous accre-

Recieved on April 12, 1996, accepted on August 2, 1996. tionary terranes with fragments of Jurassic to Cre- * Department of Earth & Planetary Sciences, Hokkaido Uni- taceous oceanic crust. These terranes were collided versity, Sapporo 60, Japan to the older rocks until the Early Cretaceous time. **Far East Geological Institute, FEB RAS, Ocean Prospect 90- Felsic igneous activities, which brought various 235, Vladivostok, 690002 Russia metallic mineral resources, are divided into Paleo- Keywords: Sikhote Alin, Gold deposit, Epithermal, Meso- zoic, Triassic-Jurassic, and Cretaceous-Paleogene thermal, ƒÂ34S, Ore mineral

267 268 S. ISHIHARA,V. V. IVANOVand V. RATKIN RESOURCE GEOLOGY:

Fig. 2 Map showing distribution of the studied gold deposits . Fig. 1 Map showing distribution of igneous rocks in the Filled circle, Late Cretaceous-Paleogene deposits; Filled diamond, Permian deposit. Large circle Sikhote Alin (after GONEVCHUKand GONEVCHUK, 1995). , ore 1 Major faults; (1) Central Sikhote Alin fault. 2 Sikhote deposit larger than 100 tons; Medium, 10-50 tons; Alin volcanic rocks. 3 Late Cretaceous-Paleogenegrani- Small, 1-10 tons of the contained Au metal . Numbers toids. 4 Early Cretaceous granitoids. 5 Triassic-Jurassic correspond to those in the text and Tables 1 and 2 . granitoids. 6 Paleozoic granitoids. K, Khabarovsk; V, occur in small bodies mainly along the eastern mar- granitoids (Fig. 1). gin of the Burea massif. They are biotite granite According to GONEVCHUKand GONEVCHUK and two mica granite which could be S or A type. (1995), the Paleozoic granitoids, 490-190 Ma, Minor Sn pegmatite and greisen deposits are asso- occur in the Burea and Khanka terranes, as well as ciated with it. in adjoined zones to the east, and are dominantly S Cretaceous-Paleogene granitoids have wide type accompanying Sn, W, REE, and Au ore depos- distribution and variable composition , but are devis- its. The Triassic-Jurassic granitoids, 220-180 Ma, ible into two groups: Early Cretaceous and Late 46(5), 1996 Gold deposits and their ƒÂ34S ratios of the Sikhote-Alin, Russia 269

Table 1 List of ore minerals of the studied deposits, Sikhote Alin.

Size of ore deposits : G, great (>100t Au); M, medium (10-50t Au); S, small (1-10t Au) El, electrum; Ar, argentite; Ag, other Ag minerals; Hg, cinnabar; Gn, galena; Sp, sphalerite; Cp, chalcopyrite TT, Tetrahedrite-tennantite; Ms, marcasite; Py, pyrite; Po, pyrrhotite; As, arsenopyrite; Bi, bismuthinite Mo, molybdenite; W, wolframite, huebnerite (h) and scheelite (s); Cs, cassiterite."

Cretaceous-Paleogene. The early Cretaceous grani- granitoids of Southern China. toids, 135-120 Ma, are peraluminus, S-type in the 3. Gold Deposits area between the Amur and Bikin Rivers, as well as those having per- or meta-aluminous character Some 2,000 tons of gold metal were obtained occurring in the zone near the Central Fault. from placer gold in the lower Amur River area, The Late Cretaceous-Paleogene granitoids, 90- indicating that the Sikhote Alin is a promising 45 Ma, are I type and related to coastal volcanic region for the primary Au mineralizations. Recent rocks of the East Sikhote-Alin volcanic belt (Fig. intensive exploration made possible to find many 1). Major Sn, W, Pb-Zn and Au deposits occur vein and fructure-controlled gold deposits in the associated with the granitoids (GONEVCHUKand Sikhote Alin (Fig. 2). GONEVCHUK,1995). The gold deposits of the Sikhote Alin have gold Tin and greisen-type W deposits are best indi- grades of 1-10g/t and are mostly small in size (less cator to identify ilmenite-series magmatism, while than 10 tons Au), but some are medium size (10-50 sulfide-forming mineralization to magnetite-series tons Au, e.g. Askold, Belaya Gora, Glukhoe and magmatism (ISHIHARA,1980). SATOet al. (1993b) Oemku) or great (more than 100 tons, e.g. Mnogov- reported these Sn and W deposits occurring mag- ershinnoe). The Mnogovershinnoe deposit is the netically low area in the central zone of the southern largest and has the highest average grade of 9.8 g/t Sikhote Alin. It appears that the Mesozoic grani- Au (Table 1). These gold deposits mostly have late toids are mostly ilmenite-series before the Early Cretaceous to Paleogene age, expect for the Cretaceous time, but both ilmenite series and mag- Komissarovskoe deposit of the Khanka massif, netite series may occur in the Late Cretaceons- which is Permian in age. Paleogene granitic belt. This tendency is broadly 3.1 Late Cretaceous-Paleogene deposits similar to late Cretaceous granitoids of the Inner Late Cretaceous-Paleogne gold deposits are Zone of Southwest Japan, but different from the seen in the northernmost part close to the mouth of Daebo Jurassic and Late Cretaceons-Paleogene the Amur river, in the East Sikhote Alin volcanic Bulgkusa granitoids in the southern Korean Penin- belt, along the Central Fault and in the south- sula, and Early Yanshanian and Late Yanshanian ernmost part around Nachodka. As gold and gold- 270 S. ISHMARA,V. V. IVANOVand V. RATKIN RESOURCEGEOLOGY:

silver deposits are related with different magmatic 3) Bukhtyanskoe deposit: Late Paleogene, complexes and formed under defferent geostruc- Small, Epithermal tural conditions, their ores belong to different min- This is small and low grade deposit occurring in eralogical and geochemical types (KHOMICHet al., Eocene basalt, early Oligocene rhyodacite, which 1989; 1995a). By these reasons, hydrothermal ores are cut by late Oligocene-Miocene basalt. It is of the Sikhote-Alin deposits are strongly variable quartz vein and veinlet type. The alteration and ore in oxygen and carbon isotopes of calcite, quartz, minerals are similar to those of Belaya Gora and adularia (IVANOV et al., 1995). The largest (IVANOVet al., 1983; IVANOV,1989). and highest grade gold deposit was found in the Central Coast northernmost area. Several gold deposits occur in the central part Northernmost area of the East Sikhote Alin volcanic belt. 1) Mnogovershinnoe deposit: Early Paleocene, 4) Oemku deposit: Late Cretaceous, Medium, Very large, Epithermal Mesothermal This is confined to a graben-like basin filled This is a mesothermal quartz vein of low sulfi- with late Cretaceous-Paleogene intermediate vol- dation type, occurring in lower Cretaceous shale canic rocks and multi-phase granitic pluton, which and sandstone intruded by pre-ore dikes of felsite are cut by Eocene and younger dikes. The deposit porphyry, diorite porphyry etc. and post-ore dike is hosted in Paleogene andesites and dacites that of diabase porphyry. The ore veins are up to 500m are genetically related to a multiphase intrusion of long and 0.2-1 in wide with the ore grade of 1.5- highly alkaline granitoids. It occurs in hydrother- 3.5 g/t Au. The ore minerals are seen in the quartz mally altered (sericite-adularia-quartz), NE-trend- vein, altered shear zone and felsite dike. Silicifica- ing vein-like zones as much as 10-12 km long that tion and chloritization are most common alter- include a series of adularia-quartz veins and vein- ation. The ore textures are massive, brecciated and lets. Some orebodies contain rhodonite-carbonate banded. Quartz (90-95%) is coarse-grained , mas- veins with lenses of skarn and sulfides . The 40Ar sive, milky-white with inclusions of the host rocks /39Ar age of hydrothermal K-feldspar shows 68.1 and disseminated calcite, adularia, albite, sericite Ma. The ore minerals, which comprise up to 1 per- and chlorite. The ore minerals are arsenopyrite, cent of veins with a Au/Ag ratio of 1, include galena, sphalerite, chalcopyrite, pyrrhotite, tetra- pyrite, marcasite, native gold, argentite, Au-Ag hedrite-tennantite, native gold, wolframite, marca- tellurides, galena, Fe-rich sphalerite, chalcopyrite site and magnetite. and freibergite (IVANOV, 1989; KHOMICHet al ., 5) Yagodnoe deposit: Late Paleogene, Small , 1989; RATKIN, 1995). Epithermal 2) Belaya Gora deposit: Late Paleogene, This is located in the late Cretaceous-Paleogene Medium, Epithermal volcano-plutonic complexes. The Cretaceous This deposit is medium in size (10-50 tons Au) rocks are'dacite, brecciated dacite and various and is intermediate in grade (0.5-5.8 g/t Au). It is tuffs. These rocks are cut by vent dacite and located in the upstream of Klchanka river, and the dacitic andesite, and hypabyssal intrusions of area is underlein by Eocene basalts and basaltic microdiorite, which hosts the orebodies, then andesite of the East Sikhote Alin volcanic belt , intruded by granodiorite. It is vein-like orebody which were cut by ore-hosting Oligocene rhyo- with many branches, parts of which are banded or dacite and dacite. These rocks are cut again by brecciated. The orebodies have alteration assem- Oligocene-Miocene basaltic andesites. The ore- blages of sericite-hydromica, quartz-chlorite- bodies are quartz vein and veinlet type and the sericite and hydromica-chlorite-sericite, which quartz is often colloform, banded and brecciated. contain a minor amount of carbonates, fluorite , epi- The vein contains adularia, chalcedony , opal, clay dote, prehnite and feldspars. The ore minerals , minerals, calcite other than quartz, and the ore min- consisting of galena, sphalerite, chalcopyrite , pyrite, erals are electrum, pyrite, marcasite , chalcopyrite, argentite, arsenopyrite, magnetite, electrum , pyrar- sphalerite, galena, argentite and other Ag minerals, gyrite, and marcasite, bismutite and aikinite, occur huebnerite, cassiterite (wood tin) , cinnabar etc. in quartz vein or veinlet and disseminated manner 46(5), 1996 Gold deposits and their ƒÂ34S ratios of the Sikhote-Alin, Russia 271 in the altered host rocks. chlorite and clay minerals. The ore minerals are 6) Salyut deposit: Late Paleogene, Small, native Au, pyrite, marcasite, pyrrhotite, arsenopy- Epithermal rite, chalcopyrite, sphalerite, galena, argentite, This is related to a dome structure of late Creta- pyrargyrite, tetrahedrite-tennantite and cinnabar ceous felsic pyroclastic rocks which are intruded (KHOMICHet al., 1995b). by various dikes of basaltic to rhyolitic composition 9) Solnechnoye deposit: Late Cretaceous, Small, and stock of granite-quartz syenite. It is steeply-dip- Mesothermal ping vein type containing quartz and small amounts This is hosted in Jurassic tuffaceous sedimentary of fluorite and adularia. Two ore types are most rocks of the Samarka terrane olistostrome. The ore- common: Au-Ag-adularia-quartz and Au-Ag-flu- bodies are vein type with minor dissemination occur- orite-quartz. The wall rocks are generally propyli- ring in altered zones of strongly crushed rocks. The tized. The ore minerals are electrum, native Ag, alteration minerals are quartz, sericite, carbonates, argentite, less commonly pyrargyrite, stephanite, clay minerals and pyrite. The ore minerals are pyrite, polybasite, miargyrite, acanthite, galena, spha- arsenopyrite, chalcopyrite, galena, sphalerite and lerite, chalcopyrite and pyrite. native gold. Central Fault zone Southernmost Region There are three ore deposits in this area, and all 10) Gordeevskoye deposit: Late Paleogene (?), are related to faulting. Small, Epithermal 7) Kornevoye deposit: Late Cretaceous, Small, This is located in the Sergeevka terrane where Mesothermal late Cretaceous-Paleogene diorite-syenite intrude This is located in the middle part of Bikin river volcanic rocks of intermediate composition. Quartz- (Fig. 1), and is related to strike-slip thrust faults. It -sericite alteration zones occur in propylitized ande- is hosted in heavily dislocated and folded, Permo- site porphyry and locally in epidotized diorite-syen- Triassic rocks of sandstone, siltstone, shale and ite. Native gold is disseminated in the altered zones tuffaceous schist. Igneous rocks are rare but repre- together with pyrite, arsenopyrite, galena, chalcopy- sented by pre-ore dikes of late Cretaceous rhyolite, rite, sphalerite, cassiterite, scheelite, stibnite, cinna- diorite porphyry and granodiorite. The mineralized bar, carbonates and tourmaline. shearzone is up to 50 m thick and 2.5kmlong. A thick 11) Vangou deposit: Late Cretaceous, Small, network zone of quartz-limonite veinlets with sili- Mesothermal cification is up to 8 m thick. Native gold, pyrite and This is also located in the Sergeevka terrane, arsenopyrite are major ore minerals. where gabbro-granitic rocks intrude older rocks 8) Glukhoye deposit: Late Cretaceous, Medi- including the Precambrians. The ores are quartz um, Mesothermal veinlets, lenes and veins, and quartz-sulfide dis- This occurs at the intersection of a large fault semination, and occur in altered rocks of sericite- and fracture zone related to the Central Fault. The hydromica, quartz-chlorite-sericite and hydromi- area is underlain by lower Cretaceous sedimentary ca-chlorite-sericite assemblages. Carbonates, epi- rocks of shale, siltstone and sandstone with lenses dote and feldspar may be present. The ore miner- of siliceous mudstone, conglomerate and synsedi- als are pyrite, galena, sphalerite, marcasite, chal- mentary brreccia. Scarce intrusive rocks are repre- copyrite, arsenopyrite and native gold. sented by small stock-like bodies and dikes of 12) Polozova deposit: Late Cretaceous, Small, quartz diorite and diorite porphyry. Mesothermal The mineralization is seen in folded and fault- This deposit has the same constituents as the crushed zones, as boudins of the host rocks and Vangou deposit. Quartz vein with minor veinlets up quartz veinlets. Sulfide contents are 1-5 percent, and to 100 m long and 10 m thick occur in the plutonic uncommonly go up to 15 percent. Pyrite-arsenopy- rocks. Quartz, sericite and pyrite are most common rite and quartz-carbonate ores as veinlets and dis- alteration minerals, and the ore minerals are can- semination are most common. The ore grades are fieldite, argentite, pyrite, chalcopyrite, galena, elec- 1.2-3.2 g/t Au in average. Gangue minerals are trum etc. quartz, carbonates, sericite, feldspars, phosphates, 13) Progress deposit: Late Cretaceous, Small, 272 S. ISHIHARA, V. V. IVANOV and V. RATKIN RESOURCE GEOLOGY:

Mesothermal rite, sphalerite, galena, tetrahedrite-tennantite and This is located in the Trudny Peninsula, southern molybdenite. Primorye. The host rocks are cataclastic and hydro- 3.2 Permian Deposit thermally altered granite, diorite and gabbro of 1) Komissarovskoe deposit: Permian, Small, possibly Paleozoic age. Veins, lenses and stock- Epithermal work filled with quartz or quartz-sulfides occur in This is located in the Laoelin-Grodekov terrane the host rocks. The alteration minerals are quartz, of southwestern Primorye. It is small in size and

sericite, chlorite, hydromica, carbonates and feld- low grade (1.5-2.0 g/t), and occurs in Permian spar, and the sericitization predominates in granite. metamorphic clastic and volcanic rocks consisting The ore minerals are pyrite, arsenopyrite, galena, of sandstone, conglomerate and argillite, and

sphalerite, chalcopyrite, marcasite and native gold. dacite and rhyolite, which were intruded by late 14) Passeka deposit: Late Cretaceous, Small, Permian granitoids. The mineralization is seen in Mesothermal sericite-quartz and micaceous-andalusite-quartz This is facing the Japan Sea in southern Pri- altered rocks near the contact with late Permian

morye. Cretaceous granitoids intrude volcaniclas- granitoids. The ore minerals are disseminated in tic rocks consisting of sandstone, shale, coaly shale, patchy form, and occur in fine veinlets of 0.5-1.5 tuff and felsite of lower Permian age. Thin and short cm in width. The ore minerals are pyrite, marca- veining is seen with silicification, sericitization site, pyrrhotite, arsenopyrite and lollingite. Au-Ag and pyritization in the granitoids. Quartz vein and minerals are electrum, native silver and chalco-

quartz-carbonates vein with brecciated texture genides. Minor minerals are scheelite, cassiterite, contain the ore minerals of native gold, pyrite, cinnaber, galena, sphalerite and chalcopyrite arsenopyrite, chalcopyrite, galena and sphalerite . (KHOMICH et al., 1995a, b). 15) Krinichnoye deposit: Late Cretaceous, Small, Mesothermal 4. Analytical Results and Discussion This area is underlein by Triassic-Jurassic clas- ƒÂ34S values of ore minerals from the gold

tic and calcareous rocks, early Cretaceous Hualaza deposits are listed in Table 2 and plotted in Figure granodiorite, which contains aplite and pegmatite 3. The values vary greatly depending upon not dikes and quartz-feldspar veins. The sedimentary mineral species but locality of the analyzed speci- rocks are intruded locally by dike and sill-like mens. Pyrite, for example, varies from -6.9 to 5 .1 bodies of intermediate-mafic composition. Zones permil throughout all the deposits. However, of closely spaced veinlets filled with quartz, quartz- detailed studies in the largest Mnogovershinnoe calcite, quartz-feldspar and quartz-limonite occur deposit indicate that ƒÂ34S values increase in the in the granodiorite. Tourmaline and chlorite may order of galena

Table 2 continued

Fig. 3 Histograms for ƒÂ34S of ore-forming sulfides from the late Cretaceous-mesothermal and Paleogene epithermal Au deposits in Sikhote-Alin. Abbreviations: as, arsenopyrite; cp, chalocopyrite; gn, galena; mo, molybdenite; py, pyrite; sb, Sb-pearceite; sp, sphalerite.

Table 2 Sulfur isotopic ratios of ores from the studied Au deposits, Sikhote Alin

Analyzed by Institute of Mineral Deposits, CAGS. * Analyzed by the Central Research Inst ., Mitsubishi Material Co., Ltd. Abbreviations: gn, galena; sp, sphalerite; cp, chalcopyrite; py, pyrite; as, arsenopyrite; tel, telludites; qz, quartz; do., ditto 274 S. ISHIHARA, V. V. IVANOV and V. RATKIN RESOURCE GEOLOGY:

ment may have played some role to these high ratios. mesothermal deposits have a wider variation than

Average values of the studied ore deposits are Paleogene epithermal deposits, mainly because the calculated as follows and plotted in Figure 4. In the late Cretaceous ones shifted towards much negative largest Mnogovershinnoe deposits, ores are dis- side, and that sediments-hosted mesothermal de- tributed in the wide area and their mineral assem- posits have negative values (e.g., Oemku, Komevoe blages are different from place to place, but they can and Solnechnaya). These average values, though be divided into those containing Au and Te-minerals number of the analyses is small, indicate no regional and those free of gold in the analyzed specimens -scale variation across the north-south trending mag -

(see parenthesis in Table 2). 534S values of suldides matic belt, like that observed in the Inner Zone of from the Au-bearing ores range from -9.3 to -1.9 Southwest Japan (Fig. 4).

permil and averages -5.4 permil (n=8), while those Sulfur isotopic ratios are most fractionated when of Au-free ores vary from -5.9 to 1.7 permil but most- the oxygen fugacity would be changed, because ly -3.4 to 0.5 permil and the average is -1.8 (n=16); 34S is preferentially partitioned to the oxidized S

thus 3.6 permil heavier than the Au-bearing ores. species. Depleted ƒÂ34S values observed on the Au 1. Mnogovershinnoe: Early Paleogene, Epithermal: -bearing ores in the Mnogovershinnoe deposits may

Base metal ores (n=16)-1.8•ñ, Gold ores (n=8) have been resulted from higher in oxygen fugacity -5 .4•ñ of the ore fluid, as compared with that of Au-free 2. Belaya Gora: Late Paleogene, Epithermal (n=4) base metal ores. -0 .6•ñ More importantly, ƒÂ34S of the ore fluids vary 3. Bukhtyanskoe: Late Paleogene, Epithermal depending upon the original composition of source (n=2) -1.8 •ñ magma. Mantle-derived magma of hot spot type

4. Oemku: Late Cretaceous, Mesothermal (n=2) may have 1 permil, yet that of subduction related, -5 .8•ñ such as magnetite-series magmas of the Japanese 5. Yagodnoe: Late Paleogene, Epithermal (n=2) island arc, the Philippines and Chile, would have 2.3•ñ more than 5 permil (SASAKI and ISHMARA, 1979 , 6. Salyut: Late Paleogene, Epithermal (n=3) 0 .0•ñ 1980; SASAKI et al., 1984).

7. Kornevoe: Late Cretaceous, Mesothermal (n=1) If the magmas would be intracted with sulfate- -3 .6•ñ bearing continental materials, it would have even 8. Glukhow: Late Cretaceous, Mesothermal (n=4) higher ƒÂ34S (ISHIHARA et al., 1986). On the con-

1.1 •ñ trary, magmas originated in or interacted with 9. Solnechnaya Dolina: Late Cretaceous, Mesother- pelitic sediments should have negative values, as mal (n=1) -6.9•ñ seen in the ilmenite-series granitoids of an average 10. Gordeevskoe: Late Paleogene, Epithermal (n=1) -5 permil in Japan (SASAKI and ISIHHARA , 1979). -1 .5•ñ Ore fluids separated from these magmas reflect 11. Vangou: Late Cretaceous, Mesothermal (n=5) these original compositions. 0.0•ñ The positive values observed on Permian deposit 12. Polozova: Late Cretaceous, Mesothenmal (n=1) indicate that the ore deposit was formed by mag- -1 .6•ñ netite-series magma or the magma interacted with 13. Progress: Late Cretaceous, Mesothermal (n=2) sulfate-bearing continental sediments of the Khanka -2 .4•ñ massif. General negative values seen on the late 14. Passek: Late Cretaceous, Mesothermal (n=3) Cretaceous-Paleogene deposits imply that the related -0 .5•ñ granitoids are dominantly ilmenite series, which has 15. Krinichnoe: Late Cretaceous , Mesothermal(n=5) been also suggested by ROMANOVSKY et al. (1995). 2.8•ñ Positive value of 2.3 permil (Yagodka) agrees 16. Askold: Late Cretaceous, Mesothermal (n=3) well with the magnetite-bearing character of the -0 .2•ñ coastal volcanic belt of ROMANOVSKY et al. (1995) , 17. Komissarovkoe: Permian, epithermal (n=2) yet those of the northern part reveal negative val- 4.6•ñ ues indicating detailed studies on opaque mineral- There is general tendency that late Cretaceous ogy are necessary here. 275 46(5), 1996 Gold deposits and their ƒÂ34S ratios of the Sikhote-Alin, Russia

activitieswere initiatedgenerally by vol- canism, then followed up by plutonism. The late Cretaceousilmenite-series mag- matismis associatedwith W(-Sn)-Cu vein and skarn mineralizationsat many locali- ties, and subvolcanicSn-W-Cu-Pb-Zn-Ag -Au vein mineralizationsat the Ikunoand Akenobe mines (A in Fig. 3). Tin poly- metallic veins of the Kavalerovoregion have somesimilarity to the Ikuno-Akenobe polymetallicveins (ISIHIHARA, 1980). A few gold deposits occur in the late Cretaceousilmenite-series igneous belt. By-product gold from the Ikuno poly- metallic deposit amountingto the medium-size scale (10-50tons Au, Class 2 of KISHIMOTOet al., 1979) is the largest in the Inner Zone. In the nearby Akenobe mine area, the ore minerals are zonedand Au-Ag veins occur in the marginalpart, separatelyfrom the.main W-Sn-Cu-Pb-Zn veinsin the center,as quartz-adularia-type veins of the Omidani(68.6 Ma, 1-10tons Fig. 4 Map showing distribution of average ƒÂ34S values of late Cretaceous- Paleogene ore deposits in the Sikhote Alin (left) and the Inner Zone of Au, Class 3) and Mikohatamines (0.1-1 Southwest Japan (right). ton, Class 4). Class 4-size Au-quartzvein K and V in the left figure are Khabarovsk and Vladivostok, respectively. deposits are also known at Tomisu and A in the right figure of the Sanyo Belt is Akenobe-Ikuno mine area. Asahi,and by-productgold in the Tsumo Japanese data from ISHIHARA and SASAKI (1991). Cu-skarndeposit is Class 4. As a whole, gold deposits are more predominant in the

The ore deposits having average ƒÂ34S values of Sikhote Alin than in the Sanyo Belt. -2 to 0 .7 permil may be related to the intermediate The Paleogene magnetite-series igneous belt is series (ISHIHARA et al., 1984), or the ore fluids origi- essentially Mo(-Pb-Zn) province. Nakase Sb deposit nated in magnetite-series magmatism might have may belong to this stage of magmatism, although been oxidized during their ascent. In the area east of no age determination hasbeen made on the ore- Vladivostok where gold deposits cluster (Fig. 2), forming minerals. This deposit contains gold SATO et al. (1993b) reported magnetic anomalies equivalent to Class 3 (KISHIMOTO et al., 1979), but and strongly magnetic magnetite-series granitoids, no other deposits contain significant amounts of which is not shown in Figure 2 of ROMANOVSKY et gold. The magnetite-series magmatism continued al. (1995). We need further detailed studies for to Miocene along the Japan Sea coast. A few even both opaque mineralogy of the magmatic rocks smaller gold deposits, such as Kamiyoshi, Takeno and ƒÂ34S of the related ore deposits to conclude the and Tajima (Class 4), occur in the Miocene belt. metasllogenesis of the gold deposits. Sulfur isotopic values of gold-bearing deposits are available on Omidani (-3.1•ñ), Ikuno (1•ñ), 5. Comparison to the Japanese Islands Tsumo (-0.1•ñ) in the ilmenite-series granitic belt

In the Japanese Islands, late Cretaceous-Paleo- (ISHIHARA et al., 1992). These values are slightly enriched in 34S among the ore deposits of the gene igneous activities are seen in the Sanyo ilmenite-series and Sanin magnetite-series belts of Sanyo Belt (Fig. 4) and somewhat similar to those the Inner Zone of Southwest Japan. Here, both late of the Sikhote Alin. Nakase deposit (5.5•ñ) and Cretaceous (95-65 Ma) and Paleogene (65-30 Ma) other ore deposits of Tertiary in age reveal typical 276 S. ISHIHARA, V. V. IVANOV and V. RATKIN RESOURCEGEOLOGY:

magnetite-series values.

In Figure 4, average ƒÂ34S values of all the ore

deposits of the Sikhote Alin and Inner Zone of

Southwest Japan are plotted, together with mag-

netite-series/ilmenite-series boundary. Although

number of the analyseeeeeis still small in the Sikhote

Alin side, the paired belt of positive and negative

values which correspond to magnetite-series/ilme-

nite-series granitoids cannot be observed in the

Sikhote Alin. Some ore deposits in the East Sikhote

Alin volcanic belt, which is supposed to be mag-

netite-series volcano-plutonic terrane, even yielded

negative values, meaning that ilmenite-series rocks

are predominant in the late Cretaceous-Paleogene

magmatism.

Late Cretaceous magmatism in the Inner Zone

of Southwest Japan is mostly ilmenite series, except

northern Kyushu. If we compare ƒÂ34S values of

this age of ore deposits in the two regions concerned,

they are somewhat similar varying more widely

toward negative side in the Sanyo Belt. Thus, late

Cretaceous magmatisms may have occurred with

common background in the Sikhote Alin and Sanyo

Belt. However, they are different from that of the

Gyeongsang basin of the southernmost Korean

Peninsula and the Fujian coast of eastern China,

because magnetite series granitoids.and positive ƒÂ34S values on the ore deposits prevail in the latter

regions (ISHIHARA et al., 1981; SATO et al., 1981;

ISHIHARA and SATO, 1982).

References

GONEVCHUK, V. G. and GONEVCHUK, G.A. (1995): Granitoid

magmatism and related mineralization in Sikhote Alin. Resource Geol. Spec. Issue, 18, 135•`142. HORIKOSHI, E. (1990): Opening of the Sea of Japan and Kuroko deposit formation. Mineral. Deposita, 25, 141•`145. ISHIHARA, S. (1980): Tin ore deposits of Primorye, USSR. Geology News, 308, 36•`45 (in Japanese). ISHIHARA, S. and SASAKI, A. (1991): Ore deposits related granitic

magmatism in Japan. Episodes, no. 3, 286•`292. ISHIHARA, S., SASAKI, A. and SATO, K. (1992): Metallogenic map of Japan: Plutonism and mineralization (3): Creta- ceous-Tertiary, 1: 2,000,000 Map Series no.15-2, Geol. Surv.Japan. ISHIHARA, S. and SATO, T. (1982) Mineral resources of China

(3) Granitic rocks of southern China. Geology News, 340, 30•`45 (in Japanese). ISHIHARA, S., SATO, K. and TERASHIMA, S. (1984): Chemical characteristics and genesis of mineralized intermediate- series granitic pluton in the Hobenzan area , western Japan. Mining Geology, 34, 401•`418. 46(5), 1996 Gold deposits and their ƒÂ34S ratios of the Sikhote-Alin, Russia 277

in Japan. Contrib. Miner. Petrol., 68, 107•`115. gy and mineral deposits in Sikhote-Alin, Russia. Geology SASAKI, A. and ISHIIIARA, S. (1980) Sulfur isotope characteris- News, 468, 16•`26 (in Japanese). tics of granitoids and related mineral deposits in Japan. SATO, K., SHIMAZAKI, H. and CHON, H. T. (1981): Sulfur isotopes Proc. 5th IAGOD Sym., E. Schweizerbartsche Verlags- of the ore deposits related to felsic magmatism in the south- buchhandlung, 399•`409. ern Korean Peninsula. Mining Geol., 31, 321•`326.

SASAKI, A., ULRIKSEN, C. E., SATO, K. and ISHIHARA, S. (1984): SHBCAZONO, N. (1987): Isotopic composition and origin of sul- Sulfur isotop reconnaissance of porphyry copper and fide sulfur of Neogene Au-Ag and base metal vein-type manto-type deposits in Chile and the Philippines. Bull. deposits in Japan. Jour. Fac. Sci., Univ. Tokyo, Sec. II, 21, Geol. Surv. Japan, 35, 615•`622. 239•`255.

SATO, K., ISHIHARA, T., VRUBLEVSKY, A. A. and ISHIHARA, S. ZALISHCHAK, B. L., PETRACHENKO, R.I. and PISKUNOV, Ya. G.

(1993) Distribution of magnetic anomalies and igneous (1978): Major original feature of the Ulsky volcano-pluton- rocks in southern Sikhote-Alin, Far East Russia. Geology ic structure (Lower Amur region). In Genesis of Endoge- News, 470, 18•`28 (in Japanese). neous Mineralization of Far East Russia (MOISEENKO, V. SATO, K., LAVRIK, N. I. and VRUVLEVSKY, A. A. (1993): Geolo- G. ed.). Vladivostok, FEB RAS SSSR, 130•`139.

ロシア,シホテアリンの金鉱床とその硫黄同位体比特に山陽帯鉱床区との比較

石原舜三・V.V.イバノブ・V.ラトキン

要旨:ロシア,シホテアリン山地は,その北部を中心に床から産出する.銀硫化物は浅熱水性鉱床において,そ砂金採集実績が2000トン以上もあり,北東ロシアにおけの種類と量が多い傾向がある,以上からシホテアリンにる3大砂金地帯の一つである.初生金鉱床の定量的情報は高硫化型金鉱床は存在せず,低硫化型でかつ比較的還はこれまで未公表であったが,当地地域には巨大規模元的なものが分布すると言える.

(金100トン以上)1,中規模(10-50トン)4,小規模(1-10 黄鉄鉱を主体とする各種硫化物の δ34Sは-9.3から5.1 トン)12の初生金鉱床が存在する.これらはペルム紀の1 パーミルの幅を持つが,一般に負の値が多い.δ34S値鉱床を除き,白亜紀後期― 古第三紀の火成岩類に関連しは浅熱水性鉱床よりも中熱水性鉱床でばらつく.また浅て,火山岩類・貫入岩類,一部堆積岩類に胚胎する.鉱熱水性のMnogovershinnoe鉱床ではAu含有量鉱石(平均床は主に石英脈・石英細脈型で,一部は断層破砕帯に鉱 -5.4パーミル)がAuを含まぬ鉱石よりも3.6パーミル低い染する.最大のMnogovershinnoe鉱床では数条の鉱脈一 δ34S値を持つ,硫黄同位体比からシホテアリンにはチ鉱染帯が10km以上にわたって分布する.鉱床は浅～中タン鉄鉱系花崗岩類が卓越することが予想される.東シの2群に分けられ,中熱水性鉱床は白亜紀小貫入岩類, ホテアリン火山岩帯に正の δ34S値が密集しないために浅熱水性鉱床は古第三紀火山岩類と成因的に関係する. 正/負の帯状配列が認められず,帯状分布が見事な西南母岩は珪化・絹雲母化・炭酸塩鉱物化・緑泥石化を受日本内帯の山陰帯/山陽帯とは明らかに異なっている. ける.脈石鉱物は石英が主体で,氷長石は半数の鉱床で, 後期白亜紀のみを見れば,チタン鉄鉱系花崗岩と負の鉱ごく稀に電気石・蛍石が見られる.鉱石鉱物は自然金・石硫黄同位体比が卓越する点で,シホテアリンは山陽帯エレクトラム・方鉛鉱・閃亜鉛鉱・黄銅鉱・黄鉄鉱・硫と似ており,韓国の慶尚盆地や中国の福建沿岸の火成活

砒鉄鉱・少量の銀鉱物が一般的で,磁硫鉄鉱も一部の鉱動とは異なる.