ARTICLE

Jingwen Mao Æ Yumin Qiu Æ Richard J. Goldfarb

Zhaochong Zhang Æ Steve Garwin Æ Ren Fengshou

Geology, distribution, and classification of gold depositsin the western Qinling belt, central China

Received: 13 June 2001 /Accepted: 1 November 2001 / Published online: 29 January 2002� Springer-Verlag 2002

Abstract Gold deposits of the western Qinling belt oc-cur within the western part of the Qinling–Dabie–Suluorogen, which is located between the PrecambrianNorth China and Yangtze cratons and east of theSongpan–Ganzi basin. The early Paleozoic to earlyMesozoic orogen can be divided into northern, central,and southern zones, separated by the Shangdan andLixian–Shanyang thrust fault systems. The northernzone consists of an early Paleozoic arc accreted to theNorth China craton by ca. 450 Ma. The central zone,

which contains numerous orogenic gold deposits, isdominated by clastic rocks formed in a late Paleozoicbasin between the converging cratonic blocks. Thesouthern zone is characterized by the easternmost ex-posure of Triassic sedimentary rocks of the Songpan–Ganzi basin. These Early to Late Triassic turbidities, inpart calcareous, of the immense Songpan–Ganzi basinalso border the western Qinling belt to the west. Carlin-like gold deposits are abundant (1) along a westwardextension of the southern zone defined by a window ofearly Paleozoic clastic rocks extending into the basin,and (2) within the easternmost margin of the basinalrocks to the south of the extension, and in adjacentcover rocks of the Yangtze craton. Triassic and EarlyJurassic synkinematic granitoids are widespread acrossthe western Qinling belt, as well as in the Songpan–Ganzi basin.

Orogenic lode gold deposits along brittle–ductileshear zones occur within greenschist-facies, highly-deformed, Devonian and younger clastic rocks of thecentral zone. Mainly coarse-grained gold, along withpyrite, pyrrhotite, arsenopyrite, and minor base metalsulfides, occur in networks of quartz veinlets, brecciatedwall rock, and are disseminated in altered wall rock.Isotopic dates suggest that the deposits formed duringthe Late Triassic to Middle Jurassic as the leading edgeof the Yangtze craton was thrust beneath rocks of thewestern Qinling belt. Many gold-bearing placers aredistributed along the river systems that flow south fromthe lode-bearing central zone.

Carlin-like gold deposits have only been identifiedduring the last decade in the southern zone of the westernQinling and in the northeastern corner of the Songpan–Ganzi basin. The deposits mainly contain micron-diam-eter gold in arsenical pyrite; are characterized by thecommon occurrence of cinnabar, stibnite, realgar, andorpiment; exhibit strong silicification, carbonatization,pyritization, and decalcification dissolution textures;and are structurally controlled. The lack of reactivehost lithologies may have prevented development oflarge (>100 tonnes of gold), stratigraphically-controlled

Mineralium Deposita (2002) 37: 352–377DOI 10.1007/s00126-001-0249-0

J. Mao (&)China University of Geoscience,29 Xueyuan Road, Beijing, 100083, P.R. ChinaE-mail: jingwenmao@263.net

Y. Qiu Æ R.J. Goldfarb Æ S. GarwinCentre for Global Metallogeny,Department of Geology and Geophysics,University of Western Australia,Crawley, WA 6009, Australia

R.J. GoldfarbUS Geological Survey, Box 25046,MS 964, Denver Federal Center,Denver, CO 80225-0046, USA

Z. ZhangInstitute of Geology,Chinese Academy of Geological Sciences,26 Baiwanzhuang Road, Beijing 100037, P.R. China

S. GarwinNewmont Mining Corporation,337 West Commercial St, Elko, NV 89801, USA

R. FengshouBureau of Geology,Exploration and Development of Gansu,Lanzhou 730000, P.R. China

Y. QiuSino Mining Ltd., 7th Floor, Sea Plaza,3A Xi Xin St., Xi’an 710004, P.R. China

Present address: J. MaoInstitute of Mineral Deposits,Chinese Academy of Geological Sciences,26 Baiwanzhuang Road, Beijing 100037, P.R. China

orebodies, which are typical of the Carlin deposits in thewestern USA. These deposits are hosted by Triassicturbidities and shallow-water carbonates, and an earlyPaleozoic inlier in the Songpan–Ganzi basin that extendsin an east–west belt for about 300 km. Rather than true‘‘Carlin’’ deposits, these Carlin-like deposits may be sometype of shallow-crustal (i.e., epithermal) hybrid withfeatures intermediate toNevada-style Carlin deposits andthe orogenic gold deposits to the immediate north. TheseCarlin-like deposits also overlap in age with the earlyMesozoic orogenic gold deposits and, therefore, alsoformed during the final stages of collision between thecratons and intermediate basin closure.

Keywords China Æ Gold Æ Qinling orogen ÆSongpan–Ganzi basin Æ Carlin-type Æ Orogenic gold

Introduction

More than 70% of China’s gold resources occur alongthe margins of the North China craton (NCC) and inadjacent orogenic belts. These include China’s mostimportant gold ores on the Jiaodong Peninsula along theeastern side of the craton (L.G. Wang et al. 1998; Qiuet al. 2002, this volume); districts of the Daqingshan,Yan-Liao, and Changbaishan gold provinces along thenorthern side (Miller et al. 1998; Hart et al. 2002, thisvolume); and deposits in the Xiaoqinling–Xiong’ershanarea of the eastern Qinling–Dabie–Sulu orogen alongthe south-central side (Mao et al. 2002, this volume).The Qinling Shan (or Qinling Mountains), in the westernpart of the Qinling–Dabie–Sulu orogen of central Chinaand along the southwestern side of the NCC, are the siteof many recently discovered gold deposits. As a result,this so-called western Qinling belt is emerging as one ofthe most important gold regions in China. Resourcestotaling more than 300 tonnes of gold (t Au) have beendelineated in this region during the last decade, includ-ing those associated with the discoveries of the Bagu-amiao (80 t Au), Shuangwang (>60 t Au), Dashui (46 tAu), and Dongbeizhai (>60 t Au) deposits. Almost allgold deposits in the belt can be classified into two dis-tinct genetic types: orogenic gold lodes hosted in latePaleozoic (mainly Devonian) clastic metasedimentaryrocks and Carlin-like deposits hosted in unmetamor-phosed to weakly-metamorphosed, mainly Middle toLate Triassic clastic and carbonate rocks. However, asdiscussed later, controversy exists regarding the classi-fication of some of the supposed Carlin-like deposits.

This study provides an overview of the distribution,mineralization styles, local geology, and tectonic settingof gold deposits within the western Qinling belt. Theremoteness of much of the region has historically hin-dered significant numbers of geologic studies, especiallycompared with the other gold-rich regions surroundingthe NCC. Mattauer et al. (1985) suggested that theQinling belt was a product of Devonian collisionbetween the NCC and Yangtze cratons. But, until re-

cently, most other studies in the western Qinling beltwere carried out by local geologists and only publishedin Chinese. Recent publications in western literature onthe Qinling orogen have predominantly focused on theultra-high pressure metamorphic rocks in the easternend of the orogen (e.g. Eide et al. 1994; Ernst and Liou1995; Hacker et al. 1996; Liou et al. 1996; Rowley et al.1997) and the now well-recognized, broad-scalePaleozoic–Mesozoic collisional history between theNCC and Yangtze cratons (e.g. Ames et al. 1993, 1996;Zhang et al. 1997; Meng and Zhang 1999).

There are remarkably few comprehensive studies inthe western literature of the more local geology in thisgold-rich area near the intersection of the Shaanxi,Gansu, and Sichuan provinces. An exception is the workby Zhou and Graham (1996) that attempted to place theextensive exposure of Triassic strata in the area into atectonic framework. Liu et al. (1991), Wang and Zhou(1994), and Li and Peters (1998) have published readilyaccessible summaries regarding the nature of some of theCarlin-like deposits in the western Qinling belt. In thispaper, we attempt to synthesize the available informa-tion from both the Chinese and western literature,combine these with field observations at many of thedeposits made by some of us, and provide basic oredeposit models that explain the gold metallogeny ofwestern Qinling. The main gold deposits that are pres-ently being mined in the western Qinling belt are listed inTable 1. Some of these are economic despite the re-ported gold grades of as low as 1–2 g/t, which to a largepart reflects the relatively cheap labor costs at mines thatare operated by workers from the local area.

Regional geology

The western Qinling belt is defined here as the western part of anarrow belt of Paleozoic through Triassic rocks deformed betweenthe NCC and Yangtze cratons in the early Mesozoic. Unlike thesouthern margin of the eastern part of this Qinling orogen, which ischaracterized by widespread blueschist facies metamorphism, onlya few scattered outcrops with high-pressure metamorphic facieshave been recognized further west. The eastern boundary to what istypically defined as the western Qinling belt within the broaderorogen is approximated by the easternmost extent of the Triassicstrata of Songpan–Ganzi remnant ocean basin, a few tens ofkilometers to the southwest of China’s ancient capital city ofXi’an (Fig. 1).

The western Qinling belt may be divided into three zones by aseries of deep-crustal fault systems. The northern zone, to the northof the Shangdan fault system, is an early Paleozoic accreted oceanicarc. The central zone consists mainly of highly-deformed MiddleDevonian to Permian flysch between the Shangdan and Lixian–Shanyang fault systems. This zone is narrow in the eastern part,becomes wide in the middle, and pinches out to the northwest(Fig. 1; Ren et al. 1991). It hosts most of the orogenic gold de-posits. The southern zone is located between the Lixian–Shanyangfault system and the Proterozoic to Early Triassic platform rocksalong the northern side of the Yangtze craton. It is defined by aneasterly-narrowing belt of the rocks of Songpan–Ganzi basin.

To the west, the boundaries of the western Qinling belt becomeobscure. Rocks in the northern zone are offset by the Qilian oro-genic belt to the north of our study area. Other units are hiddenbeneath the Triassic strata of the enormous Songpan–Ganzi basin.

353

Table

1.Summary

ofgold

depositsin

thewestern

Qinlingbelt

Deposit

Counties/province

(long.andlat.)a

Genetictype

Hostrock

Spatiallyassociated

intrusions

Gold-relatedminerals

Alterationminerals

Resource(t)/

grade(g/t)

Liba

Lixian/G

ansu

(104�35¢24¢¢E

,34�06¢00¢¢N

)

Orogeniclode

gold

MiddleDevonianslate,

siltstone,andphyllite

EarlyMesozoicbiotite

adamellite

Pyrite,arsenopyrite,

pyrrhotite,chalcopyrite,

galena

Pyrite,sericite,quartz,

carbonate,rutile,

chlorite,biotite,

tourm

aline

>50/3.6–5.4

Jinshan

Lixian/G

ansu

(104�47¢00¢¢E

,34�12¢00¢¢N

)

Orogeniclode

gold

MiddleDevoniansilty

phyllite

Mesozoicadamellite

Pyrite,arsenopyrite,

pyrrhotite,chalcopyrite

Pyrite,sericite,

quartz,carbonate

3/5.5

Maquan

Lixian/G

ansu

(104�48¢00¢¢E

,34�12¢00¢¢N

)

Orogeniclodegold

MiddleCarboniferous

phyllite

Mesozoicadamellite

Pyrite,arsenopyrite

Sericite,quartz

3/5

Anjiacha

Xihe/Gansu

(105�27¢00¢¢E

,34�56¢00¢¢N

)

Orogeniclodegold

MiddleDevonianclastic

rocksandcarbonate

Mesozoicadamellite

Pyrite,arsenopyrite

Sericite,quartz

3.1/5.6

Lu’erba

Minxian/G

ansu

(103�57¢30¢¢E

,34�22¢05¢¢N

)

Orogeniclodegold

MiddleTriassicsiltyslate

None

Pyrite,stibnite

Sericite,quartz

17/3–8

Dingping

Hequ/G

ansu

(102�48¢00¢¢E

,34�00¢06¢¢N

)

Carlin-like

MiddleDevonian

tuffaceousslate

None

Pyrite,arsenopyrite,

cinnabar

Sericite,quartz

11.5/5.2

Jiuyuan

Zhouqu/G

ansu

(104�16¢00¢¢E

,33�51¢20¢¢N

)

Carlin-like

MiddleDevonian

limestone

Mesozoicgranodiorite

porphyry

Pyrite,sphalerite

Quartz,pyrite

0.6/8.5

Luoda

Diebu/G

ansu

(103�56¢00¢¢E

,33�54¢00¢¢N

)

Carlin-like

Siluriansandyslate,

phyllite

Granodiorite

Cinnabar,arsenopyrite,

pyrite

Quartz,sericite

<1/5

Chabu

Diebu/G

ansu

(103�48¢18¢¢E

,34�03¢18¢¢N

)

Carlin-like

Carboniferouslimestone

andslate

None

Pyrite

Quartz

1/4

La’erm

aLuqu/G

ansu

(102�19¢12¢¢E

,34�00¢02¢¢N

)

Carlin-like

Cambrian-Ordovician

carbonaceousand

siliceousslate

Mesozoicdioritedikes

Pyrite,cinnabar,stibnite

Quartz,barite,

sericite

23/1.5–5.6

Dashui

Maqu/G

ansu

(101�59¢00¢¢E

,35�05¢00¢¢N

)

Carlin-like

Triassicto

Early

Jurassiccarbonaterock

Mesozoicgranodiorite

Pyrite,limonite,hem

atite

Quartz,pyrite,

dolomite,kaolinite,

calcite

46/5–60

Zhongqu

Muqu/G

ansu

(101�58¢50¢¢E

,34�10¢00¢¢E

)

Carlin-like

MiddleTriassic

carbonate

rock

Mesozoicgranodiorite

Nativegold,pyrite,

quartz,calcite

Quartz,pyrite,

carbonate

3/7.6

Gongbei

Maqu/G

ansu

(102�12¢47¢¢E

,34�00¢00¢¢N

)

Carlin-like

MiddleTriassic

carbonate

rock

Mesozoicgranodiorite

Pyrite,stibnite

Quartz,pyrite,

carbonate

6/2–6

Shijiba

Wenxian/G

ansu

(104�35¢00¢¢E

,33�00¢00¢¢N

)

Carlin-like

Early-M

iddle-Devonian

siltstone,fine-grained

sandstone

Mesozoicgranodiorite

dikes

Pyrite,arsenopyrite

Sericite,quartz,

carbonate

15/5.8–8.1

Dongbeizhai

Songpan/Sichuan

(102�45¢36¢¢E

,32�18¢00¢¢N

)

Carlin-like

MiddleTriassicsandy

slate

Mesozoicdioritedikes

Arsenopyrite,pyrite,

realgar,arsenopyrite,

stibnite,scheelite,

marcasite

Quartz,calcite,pyrite

>52/5.5

354

Manaoke

Jiuzhaigou/Sichuan

(103�24¢00¢¢E

,32�18¢00¢¢N

)

Carlin-like

Triassicsandyslate

andminor

carbonate

None

Pyrite,stibnite,

scheelite

Sericite,

pyrite

21/3.2

Jinmuda

Rangtang/Sichuan

(101�06¢00¢¢E

,32�22¢00¢¢N

)

Carlin-like

Triassicsiltyslate

andquartz

diorite

Mesozoicquartzdiorite

Pyrite,stibnite,

sphalerite,calaverite

Quartz,pyrite

8/1.6–2.6

Weiguan

Litang/Sichuan

(103�5¢11¢¢E

,31�29¢31¢¢N

)

Carlin-like

Diorite

Mesozoicdiorite

Pyrite,stibnite,sphale-

rite,galena,chalco-

pyrite,arsenopyrite

Quartz,sericite

6.1/2.9–54

Yinchang

Pingwu/Sichuan

(103�21¢00¢¢E

,31�58¢00¢¢N

)

Carlin-like

Triassicsiltyslate,

carbonate,quartzite

None

Pyrite,arsenopyrite,

cinnabar,stibnite,

magnetite

Carbonate,quartz

11/3.8

Qiongme

Ruo’ergai/Sichuan

(102�29¢00¢¢E

,34�24¢30¢¢N

)

Carlin-like

Cambriancarbonaceous

andsiliceousmudstone,

anddioriteporphyry

Mesozoicdiorite

Pyrite,stibnite,sphale-

rite,chalcopyrite

Sericite,quartz

4/3.8

Baxi

Ruo’ergai/Sichuan

(104�01¢29¢¢E

,33�02¢00¢¢N

)

Skarn

MiddleTriassic

Limestone,dolomite,

sandstone

Mesozoic

quartzdiorite

Pyrite,arsenopyrite,

chalcopyrite,galena,

sphalerite,stibnite

Garnet,diopside,

wollastonite,quartz

6.4/4

Lianhecun

Nanping/Sichuan

(104�28¢00¢¢E

,33�02¢00¢¢N

)

Carlin-like

EarlyDevonianslate

EarlyMesozoic

graniteporphyry

Pyrite

Quartz,pyrite,

barite,sericite,

calcite,feldspar

10/4

Qiaoqaioshang

Songpan/Sichuan

(103�38¢00¢¢E

,32�44¢00¢¢N

)

Carlin-like

MiddleTriassic

carbonaceousslate,

phylliteandbioclastic

carbonate

Mesozoicgranite

porphyry

Pyrite,realgar

Quartz,pyrite,

carbonate,sericite

15/4

Zheboshan

Songpan/Sichuan

(103�18¢15¢¢E

,32�53¢06¢¢N

)

Carlin-like

MiddleTriassic

interm

ediate

andfelsic

volcanicrocksand

turbidite

None

Pyrite,arsenopyrite,

sphalerite,chalcopyrite

Quartz,pyrite,sericite,

feldspar,chlorite

2/5

Jindonggou

Pingwu/Sichuan

(104�45¢40¢¢E

,32�20¢10¢¢N

)

Carlin-like

Silurianphyllite

Mesozoicgranite

Pyrite

Quartz,sericite,

pyrite,siderite

5/5.9

Rangtang

Rangtang/Sichuan

(100�52¢30¢¢E

,32�21¢50¢¢N

)

Orogenic

lodegold

Triassicslate

and

metasandstone

Mesozoicdiorite

Pyrite,marcasite,

hem

atite,magnetite,

stibnite,arsenicalpyrite

Quartz,pyrite,

sericite,carbonate,

andchlorite

10/0.2–1.2

Shuangwang

Taibai/Shaanxi

(107�12¢00¢¢E

,34�51¢40¢¢N

)

Orogenic

lodegold

MiddleDevonianschist

andphyllite

Late

Triassic–Early

Jurassicquartz

monzodiorite

and

monzogranite

Pyrite,calaverite,

tellurbismuth,hessite,

millerite,violarite

Albite,ankerite,

pyrite,quartz,rosco-

elite,rutile,tourm

a-

line,apatite,sericite

60/1.5–3.5

Lijiagou

Mianxian/Shaanxi

(106�28¢00¢¢E

,33�08¢00¢¢N

)

Orogenic

lodegold

Late

Proterozoic

dolomiteandslate

MiddlePaleozoic

ultramafic–interm

ediate

intrusions

Chalcopyrite

Quartz,albite,siderite,

dolomite

0.8/8.9

Jianchaling

Lueyang/Shaanxi

Carlin-like

Ultramaficrocksand

Late

Proterozoic

dolomite

EarlyMesozoic

granodiorite

Pyrite,nativesilver,

violarite,pentlandite

Pyrite,quartz,dolo-

mite,ankerite,

serpentine,talc

52/5

Donggouba

Lueyang/Shaanxi

(106�20¢20¢¢E

,33�14¢00¢¢N

)

Carlin-like

Middle–Late

Protero-

zoicspilite–kerato-

phyre,tuff

Quartzporphyry

Pyrite,sphalerite,

galena,chalcopyrite,

tetrahedrite

Quartz,sericite,barite

6.3/2

355

Carlin-like gold ores occur here in two distinct clusters: (1) an east–west belt of deposits (e.g. La’erma, Dashui, Dingping, etc.) occursalong a narrow window of Cambrian to Ordovician clastic andcarbonaceous rocks, termed the Bailongjiang compound anticline,extending for hundreds of kilometers into the Songpan–Ganzibasin in what we classify as a part of the southern zone of thewestern Qinling, and (2) in a broad group mainly hosted by Middleto Late Triassic clastic rocks along the extreme east-central marginof the basin (e.g. Manaoke, Dongbeizhai), with some ores (e.g.Shijiba) also in the adjacent older continental margin strata of theYangtze craton (Fig. 1).

North China craton and adjacent rocks of the northern zoneof the western Qinling belt

The NCC (sometimes referred to as the Sino-Korean craton)bounds the Qinling–Dabie–Sulu orogen to the north (Fig. 1). Thebasement of the craton is locally as old as 3.8 Ga (Liu et al. 1992),although the portion adjacent to the western Qinling belt is noolder than ca. 2.8–2.5 Ga (Kroner et al. 1988). The craton consistsof a basement of Archean to Proterozoic metamorphic rocks thatare overlain by Sinian metasedimentary and metavolcanic rocksimmediately north of the western Qinling belt (Hsu et al. 1987;Zhang et al. 1995). These schists, quartzites, amphibolites, andmarbles, in part, comprise what has been termed the KuanpingGroup (Fig. 1).

The passive margin rocks of the Kuanping Group are separatedby a shear zone, to the south, from a series of mafic to intermediatevolcanic rocks. These early Paleozoic sequences, the Erlangping andQinling Groups, have been interpreted as an intraoceanic arccomplex accreted to the craton margin by ca. 400 Ma (Xue et al.1996a, 1996b). They were metamorphosed to medium and highgrades during the collisional episode, but show no evidence of post-Early Devonian metamorphic events (Zhai et al. 1998). To the westof the Hulu River, the Erlangping and Qinling Group rocks aregenerally overlain by Cretaceous to Cenozoic continental cover. Aseries of ophiolite bodies, defining the Shangdan fault zone, delin-eates the southern boundary of the arc complex (Zhang et al. 1995).

Late Paleozoic basinal rocks of the central zoneof the western Qinling belt

A basinal flysch sequence, the host for orogenic-type gold deposits,filled a large trough to the south of the Shangdan fault and formedwhat we refer to as the central zone of the western Qinling belt.This has been given a series of names in the literature including theDevonian trough of Mattauer et al. (1985), flysche nappe (Hsu et al.1987), northern South Qinling microplate (Zhang et al. 1995, 1996),and Xinyang Group (Zhai et al. 1998). The flysch is mainlyDevonian in age, although it includes a few relatively small out-crops of Carboniferous and Permian metasedimentary rocks. Ar-gon thermochronology indicates that much of flysch, wasmetamorphosed to medium-grade facies in the Late Carboniferous(Zhai et al. 1998). This is coeval with a period of significant strike-slip motion along the northerly-bordering Shangdan fault zone atca. 315 Ma (Mattauer et al. 1985). Flysch lithologies are dominatedby slate, graywacke, conglomerate and amphibolite, but the occa-sional occurrence of limestone and breccia blocks near many of thegold deposits indicates melange-like assemblages are also present.In fact, Hacker et al. (1996) describe an extensive unit of carbonate-hosted melange, the Meishan formation, within the belt of basinalrocks a few hundred kilometers to the east of the orogenic goldores.

Although highly deformed into a series of thin nappes, there issurprisingly little evidence for major late Paleozoic, syn-kinematicthermal events. Metasedimentary rocks dip to the north, parallel tothe Shangdan fault zone, but there are no post-Caledonian meta-morphic ages from the northern zone of the western Qinling belt(Zhai et al. 1998). This perhaps suggests limited amounts ofunderthrusting during basin closure, but no actual subduction ofT

able

1.(Contd.)

Deposit

Counties/province

(long.andlat.)a

Genetictype

Hostrock

Spatiallyassociated

intrusions

Gold-relatedminerals

Alterationminerals

Resource(t)/

grade(g/t)

Ma’anqiao

Zhouzhi/Shaanxi

(108�02¢30¢¢E

,33�49¢50¢¢N

)

Orogeniclodegold

Devonianphylliteand

metasiltstoneinter-

bedded

withmarble

EarlyMesozoic

granodioritestock

Pyrrhotite,pyrite,

sphalerite,arsenopyrite,

chalcopyrite

Quartz,sericite,pyrite,

biotite,chlorite,

pyrrhotite,dolomite,

calcite,plagioclase

20/5.5

Pangjiahe

Fengxian/Shaanxi

(106�32¢00¢¢E

,34�01¢55¢¢N

)

Orogeniclodegold

Middle–Late

Devonian

phyllite,metasandstone,

metasiltstone

EarlyMesozoic

adamellite

andbiotite

granitestocks

Pyrite,arsenopyrite

Quartz,calcite,pyrite,

sericite,chlorite

8/1.2–5.9

Baguamiao

Minxian/Shaanxi

(106�57¢00¢¢E

,33�54¢30¢¢N

)

Orogeniclodegold

MiddleDevonian

phyllite,limestone,

siltstone,slate

Mesozoicaplite

and

dioritedikes

Pyrite,pyrrhotite,

sphalerite,marcasite,

chalcopyrite,

molybdenite,galena

Sericite,quartz,

ankerite,pyrrhotite,

pyrite,calcite,albite,

chlorite,biotite,

tourm

aline

80/2.2–7.9

aLongitudeandlatitudeofthedeposit

356

the central zone rocks beneath the northern zone along theShangdan fault zone. In fact, there are only a few rare and ques-tionably dated Variscan (late Paleozoic) granitoids recognized inthe northern zone or near the gold ores in the central zone.Apparently, Variscan tectonism was relatively restricted in area andlimited in extent along the western Qinling belt.

Triassic turbidites of the Songpan–Ganzi basin and of thesouthern zone of the western Qinling belt

The largest single exposure of Triassic rocks on Earth is that of theSongpan–Ganzi basin that fills the broad area between the NorthChina, Yangtze, and Tarim cratons, and the North Tibet block.Most workers agree that this flysch represents the outwashed sed-iment from the diachronously east-to-west-forming Qinling orogen,which developed between the colliding NCC and Yangtze craton,although the exact provenance is still arguable (Nie et al. 1994;Avigad 1995; Zhou and Graham 1996; Bruguier et al. 1997). A shiftin lithostratigraphy within the basin, from Lower Triassic pelagicmicrites with pre-Triassic fossils, to Middle to lower Upper Triassicsiliciclastic turbidites, is consistent with the unroofing of a cratonicblock subsequent to erosion of its adjacent platform (Zhou andGraham 1996). The lack of any ultra-high pressure minerals withinthe Triassic sediments suggests erosion from the uplifting southernmargin of the NCC and not the leading edge of the Yangtze craton

(Bruguier et al. 1997). During the Late Triassic, the sedimentaryrocks on the eastern side of the basin were folded and thrusteastward over the passive margin of the Yangtze craton throughoutmuch of the area on the southwest side of the western Qinling belt.They were also subducted to the north below the evolving Qinlingorogen (Bruguier et al. 1997).

The eastern arm of the Songpan–Ganzi basin forms thesouthern side of the southern zone of the western Qinling belt.Detailed lithofacies and petrographic descriptions of these Triassicrocks are given by Zhou and Graham (1996). They discuss thelikely folding and thrusting of these rocks at ca. 220–210 Ma. Thiskinematic event probably included subduction of crust beneathPaleozoic rocks to the north, along the Lixian–Shanyang faultzone, as diachronous collision between the two cratonic masses wasending. The Indosinian (i.e., Early Triassic) granitoids north of thefault, including those near many of the orogenic gold deposits, maybe products of such subduction.

A detailed sedimentological study of the turbidites in the east-ern Songpan–Ganzi basin was conducted by Gu (1994) in the im-mediate vicinity of many of the Carlin-like gold deposits. Gold oresare spread throughout the >4-km-thick Middle to Late Triassicbasin margin sequence. Lithologies are dominated by slate andarkosic graywacke, with the lower few hundred meters of thestratigraphy being notably calcareous (Gu 1994). The ‘‘altered’’graywackes and slates of this part of the basin are reported toaverage 20 and 11 ppb Au, 122 and 186 ppm As, and 20 and 8 ppmSb, respectively (Gu 1994).

Yangtze craton

The leading passive margin strata of the Yangtze craton formthe southern boundary of the Qinling–Dabie–Sulu orogen. Thebasement of the craton comprises Archean to Early Proterozoichigh-grade metamorphic rocks, which historically have been

Fig. 1. Simplified geological map of the western Qinling belt,central China (modified from Zhang et al. 1995), showing thedistribution of selected gold deposits and major structures. Theinsert shows the location of the western Qinling belt in the Qinling–Dabie–Sulu (QDS) orogen. The Jiaodong (Qiu et al. 2002, thisvolume) and Xiaoqinling–Xiong’ershan (Mao et al. 2002, thisvolume) gold provinces, to the east, are also indicated

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thought to be much younger than those of the NCC. However, newSHRIMP U–Pb zircon data indicate that ca. 2.95 Ga granitoidsintrude ca. 3.2 Ga crust along the northern Yangtze craton (Qiuet al. 2000). Cover strata along the northern and western marginsof the craton include about 12 km of Sinian to Early Triassicmarine carbonates, cherts, quartzites, and shales (Hacker et al.1996). These platform and shelf facies rocks, south of the Mianluefault zone (Fig. 1), are weakly-foliated and regionally metamor-phosed to only very low grades. Post-Middle Triassic stratigraphicsequences within the craton and platform areas are continentalsedimentary rocks, including coal-bearing clastic rocks (Jurassic)and red clastic rocks (Cretaceous to Paleocene). A few of theCarlin-like gold deposits are also in the cratonic cover rocks (Fig. 1).

Granitoids

Phanerozoic granitoids are scattered throughout the westernQinling belt (Li et al. 1993; Fig. 1), but detailed study of these islacking. They occur as plutons and stocks, normally a few hundredsquare meters to several square kilometers in area and rarely>100 km2 in size. Granodiorite and monzogranite are the mostcommon rock types. The granitoids south of the Shangdan faultzone are generally reported to be typical I-type with a low initial Srratio (mainly <0.705); have low silica, aluminum, and alkalinecomponents; and have high contents of basic components. They areinterpreted to have been derived from partial melting of the lowercrust and/or upper mantle (Hsu et al. 1987; Li et al. 1993). In thewestern Qinling belt, the granitoids are often well-exposed nearmany of the orogenic gold deposits. In addition, very smallgranitoid stocks or swarms of felsic and lamprophyre dikes areobserved in the Triassic turbidities in Songpan–Ganzi basin (SGB)and in platform rocks of the Yangtze craton.

Most granitoids are widely cited as being Mesozoic in age inpublications in the Chinese language literature. A scattering of agesbetween ca. 240 and 180 Ma characterizes many of the largerplutons that have been dated by a variety of methods throughoutthe belt (Li et al. 1993; Li and Li 1994; Shi et al. 1993; Wang et al.1998a; Lu 1999). Detrital zircon data from flysch in the Songpan-Ganzi basin provide evidence that significant magmatism wasoccurring during the Triassic sedimentation in the basin (Bruguieret al. 1997). The range of ages also overlaps with the ca. 225–190 Maperiod of maximum oblique collision between the two cratonicblocks (Gilder and Courtillot 1997) and is the probable peak oforogenesis. In addition, however, older dates spread throughoutthe Carboniferous are reported for smaller felsic and mafic dikesscattered within the western Qinling belt (Li et al. 1993). Older, ca.500–400 Ma Caledonian intrusions are restricted to areas north ofthe Shangdan fault zone, having formed during collisional episodesbetween the older arcs and the southern margin of the NCC (Lerchet al. 1995; Zhai et al. 1998). There are few data supporting anyCretaceous magmatism in the western Qinling belt, in contrast tosuch widespread activity in the eastern side of the Qinling orogen(e.g. Xue et al. 1997) and elsewhere around the margin of theeastern side of the NCC (Wang et al. 1998; Qiu et al. 2002, thisvolume).

Orogenic gold deposits of the western Qinling belt

The most productive gold deposits of the westernQinling belt lie between the Shangdan and the Lixian–Shanyang fault zones (Fig. 1), in an elongate beltextending for more than 200 km from Fengxian(Shaanxi province) in the east to Lixian (Gansu prov-ince) in the west. Gold deposits in the belt, hosted by thelate Paleozoic flysch sequence, appear to mainly fit theorogenic gold deposit type model (Goldfarb et al. 1998;Groves et al. 1998). Li and Peters (1998) concluded that

these ores in the central zone can be classified as Carlin-like, but, as a whole, they consistently lack many criticalfeatures diagnostic of such a deposit type. The largestresources occur at Baguamiao (>80 t Au), Shuangwang(>60 t Au), Ma’anqiao (>50 t Au), and Liba (>50 tAu), with smaller deposits at Ertaizi, Yawanli, Jinshan,Maquan, Pangjiahe, Jiucaigou, Sanrengou, Anjiacha,Chajiazhuang, Luojiacha, and Laotiechang. These lode-gold deposits can be further divided into three styles, asdiscussed below: brittle fault-hosted disseminated type(e.g., Liba, Jinshan, Maquan), ductile shear zone type(e.g., Baguamiao, Pangjiahe, Chajiazhuang), and brecciatype (e.g., Shuangwang and Anjiacha). The distributionof all three types is apparently controlled by WNW-striking faults that are parallel to the Shangdan faultzone. Dolomitic limestone units in the late Paleozoicbasin sequence also host poorly studied massive lead–zinc deposits, which include Changba, the second largestlead–zinc deposit in China (Zhai et al. 1999). Althoughapparently genetically unrelated to the orogenic goldores, some of the gold deposits were discovered duringbase metal exploration programs.

Characteristics of the orogenic gold deposits

Many of the lode gold deposits hosted in the Devonianto Carboniferous rocks clearly occur along ductile tobrittle shear zones. In general, the mineralized structuresexhibit ductile deformation that is overprinted by laterbrittle faulting, both of which appear to be gold-related.Primary ores in the orogenic gold deposits vary fromfine- to coarse-grained native gold, with the latter easilyvisible in hand specimens from most deposits. Pyrite isthe most common sulfide mineral, with lesser amountsof pyrrhotite, arsenopyrite, galena, sphalerite, andchalcopyrite. Framboidal pyrite, realgar, orpiment, andcinnabar are absent in these deposits, except for in lateassemblages at the Baguamiao deposit, in contrast to thedeposits classified as Carlin-like elsewhere in the westernQinling belt.

Mineralization styles of the orogenic gold deposits,although apparently controlled by fault structures,contrast with those of the deposits in the Xiaoqinling–Xiong’ershan region to the east (Mao et al. 2002, thisvolume). At the latter, gold occurs in large quartz veins,hosted in Archean or Proterozoic basement rocks,whereas the western Qinling gold deposits mainly occurdisseminated in altered, locally brecciated, Paleozoicmetasedimentary rocks and as masses of thin quartzveinlets along the shear zones. The mineralized struc-tures are also sites of lamprophyre and diorite dikeemplacement. Some dikes are mineralized, indicatingintrusion was pre-gold, although post-gold dikes are alsoreported in several deposits.

Gold deposits of the ductile shear type are locatedwithin or adjacent to the major deep faults in the centraland eastern parts of the central zone. Individualauriferous veinlets in these deposits are typically only

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millimeters to centimeters wide, but together define bilkminable areas characterized by extensive silicification.These dense quartz veinlet systems, typically with highgold grades, tend to overprint earlier disseminated goldores. They show spatial associations with dilational foldhinges along the major shear zones. Baguamiao is themost significant deposit of the ductile shear type.

The disseminated style of gold mineralization occursin more shallowly developed and smaller brittle defor-mation zones. Deposits of this type are concentrated invisibly altered wall rock adjacent to brittle fractures inthe Lixian region in the western part of the central zone.Many of these fracture-related gold deposits are hostedin brittle faults surrounding granitoid bodies, whichsuggests that relatively competent hornfels zones werefavored areas of dilation. Typical gold deposits of thistype include Liba and Jinshan.

Breccia-type gold deposits in Middle to Late Devo-nian slates, phyllites, sandstones, and lesser limestonesare thought, by some workers, to be a style of gold de-posit unique to this part of China. They are restricted tothe same general area as the ductile shear style ores and,therefore, may represent just the relatively more brittlestructures in the same broad lode systems. Low-grade(1.5–3.5 g/t, average 2.6 g/t), but high-tonnage, ores arebest developed along fault zones that are characterizedby breccias cemented with albite, ankerite, and otherhydrothermal minerals. Gold grains occur in the albite-and ankerite-rich cements and medium-sized brecciaclasts. The Ag, Pt, and Pd contents of the ores are high,although reported concentrations of as much as 2.66%Pt and 0.35% Pd in some pyrite grains (Shi et al. 1993)probably should be reconfirmed.

Examples of the most important of these orogenicgold deposits are presented in more detail below. Theyinclude the ductile shear zone style ores of the Bagu-amiao deposit, the breccia style at the Shuangwang de-posit, and the disseminated style at a few of the otherwestern Qinling belt gold deposits.

Baguamiao

The Baguamiao deposit, the largest gold deposit in thewestern Qinling belt, is located about 50 km southwestof the town of Baoji (Fig. 1). This shear zone-hostedgold deposit was discovered in the early 1990s, a 500-t/day mill was constructed in 1996, and mining began in1997. The deposit is hosted in Middle Devonian strata ofthe Xinghongpu Formation, which locally consists ofphyllite, marl, and limestone (Fig. 2). Albite-rich apliteand porphyritic diorite dikes occur in the deposit area.Early Mesozoic granodiorite batholiths are locatedabout 20 km to the southeast and northwest (Fig. 1). Aseries of WNW-striking compressional folds and faultsin the mine area parallel the regional Shangdan faultzone. Gold, both within distinct veinlets and in alteredcountry rock, occurs in mylonitic shear zones charac-terized by massive silicification along a major fold axis.

Gold ores at the Baguamiao deposit are concentratedin three zones of ductile deformation, with the northernzone being the largest. This NW-striking ore zone is1,680-m-long, 50- to 160-m-wide, and 120- to 520-m-deep (Fig. 2), with grades in eight distinct orebodiesranging between about 3 and 6 g/t. The largest indi-vidual orebody (no. 14) is 500-m-long, 1.8- to 22-m-wide, and >200-m-deep, with an average gold grade of2.9 g/t. The central and south zones have been poorly-explored and, although of similar grade, they have lowerresource potential. In general, gold grades are discon-tinuous along strike and dip in all the zones, but groupsof narrow quartz veinlets in bleached zones make thebulk of the altered shear zone an economic target.

The mineral assemblage is simple and the ore min-erals comprise less than 5% of the veinlet masses. Pyriteand pyrrhotite are dominant, with minor to trace chal-copyrite, molybdenite, titanite and native gold, and raresphalerite and galena. Quartz, sericite, ankerite, andchlorite are the main gangue minerals, with lesser bio-tite, albite, and tourmaline. Scattered ore and gangueminerals define a banded texture at the Baguamiao de-posit, characterized by the light-colored quartz–ankeritezones interlayered with dark-colored zones of chlorite,biotite, and pyrrhotite. Broad bleached zones, caused by

Fig. 2. a Schematic geological plan and b cross section of theBaguamiao gold deposit, Shaanxi province (after Wei et al. 1994).The stratigraphic sequence in the mine comprises the MiddleDevonian Xinghongpu carbonates and calcareous phyllite. Ore-body no. 14 is the largest of the deposit

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continuous sericitization and chloritization, extend 50 to200 m outward from the vein networks. Overall altera-tion intensity, the abundance of biotite (locally exceed-ing 10% of the rock), and the occurrence of sphaleriteand galena increase with depth.

Native gold occurs as irregular grains, in sheets, indendritic shapes, and rarely as pyritohedrons. About35% of the gold is >0.1 mm in diameter, 45% is 0.01–0.05 mm and 20% is finer than 0.01 mm. The fineness ofgold varies from 836 to 960, and averages 888 (Wei et al.1994). Two gold-related hydrothermal events include (1)early shearing and folding with deposition of quartz,ankerite, sericite, sulfide minerals, and gold in foldedand deformed quartz veins and fractured wall rocks, and(2) later brittle deformation with gold-bearing quartzveins and bleached zones within and surrounding joints.

Shuangwang

The Shuangwang gold deposit is about 35 km east of theBaguamiao deposit along the same WNW-striking trendbetween the Shangdan and Lixian–Shanyang regionalfaults (Fig. 1). It was one of the first deposits discoveredin the western Qinling belt in the early 1980s and goldproduction began there in the early 1990s. Gold miner-alization in the deposit principally developed in albite-and ankerite-dominated cements that form the matrix toslate and limestone breccia blocks between more localfaults (Fig. 3).

Eight distinct breccia bodies are distributed along an11.5-km-long, 400- to 500-m-wide, WNW-striking zonein Middle Devonian schist and carbonaceous phyllite ofthe Gudaoling Formation, which is the same sequencethat hosts the Baguamiao deposit. This breccia zonedeveloped between the Wangjialeng and Xiushiya strike-slip faults (Fig. 3a) that cut the northern limb of theXiba composite anticline. A quartz monzodiorite andmonzogranite batholith intruded the axis of the Xibaanticline at ca. 214–198 Ma. This WNW-strikingbatholith is 1–3 km southwest of the Shuangwang de-posit and exposed over an area of about 150 km2.Granitic porphyry dikes and minor lamprophyre dikesintrude and cut the breccia bodies.

The WNW-striking zone of brecciation at the Shu-angwang deposit is recognized over a vertical extent ofat least 1 km (Fig. 3b). This deposit area is divided intothe western and eastern sections, with a total of 14 dis-tinct orebodies delineated and confined to the brecciabodies, using a cutoff grade of 1.0 g/t Au. The ten ore-bodies in the western section are scattered along a lengthof 1,000 m in the 6.5-km-long section. These irregularly-shaped orebodies are 25- to 132-m-long and about 2- to12-m-wide, with average gold grades of 1.2–6.9 g/t. Thefour orebodies of the eastern part of the deposit havegold grades averaging 2.9 g/t, and are typically 20- to500-m-long, 4- to 26-m-wide, and more than 200-m-deep. They are concentrated in a 3,000-m-long zone inthe 5-km-long eastern section.

The breccias contain angular fragments of countryrock that show little sign of transport, except formovement during shear deformation. Fragments varyfrom several centimeters to tens of meters in length, withthe larger breccias typically at shallower levels. Datasuggest that highest gold grades are associated withmedium-sized (10- to 50-cm-long) breccias fragmentsand their cements, whereas both finer (<10-cm-long)and coarser (>50-cm-long) breccias are relativelypoorly-mineralized (Shi et al. 1993). The cement to thebreccias is dominated by albite, ankerite, quartz, mus-covite, sericite, rutile, and sulfide minerals, with the firsttwo minerals being most abundant.

Hydrothermal alteration is well-developed in theclasts of the breccia bodies. In areas of most intensealteration, clastic rock fragments have been mainly al-tered to massive albite (>95%), with minor ankeriteand rutile, although hydrothermal sericite may locallyform 70% of the altered rock. In less-altered areas, an-kerite and albite occur in roughly equal amounts. Wherebreccias are developed in carbonate-rich layers, therocks are altered to albitic marbles. Albite veins are alsodeveloped along fractures within clasts and these maylocally contain ankerite, tourmaline, apatite, rutile, sul-fide minerals, and gold.

More than 40 ore minerals are recognized in the de-posit (Shi et al. 1993) with pyrite being the dominantmetallic mineral. Minor to trace amounts of native gold,tellurides (calaverite, tellurbismuth, and hessite), nickel-bearing minerals (millerite, violarite, polydymite, andparkerite), goldmanite, parisite, molybdenite, pyrrhotite,arsenopyrite, tetrahedrite, sphalerite, chalcopyrite, ga-lena, and willyamite have been observed. Bulk analysisof hydrothermal pyrites reveals that they are enriched inplatinum and palladium (Shi et al. 1993). Syngeneticpyrite is disseminated in some breccia fragments, butcontains little gold. The majority of gold is sited in hy-drothermal pyrite, which occurs as veinlets, massiveclots, and disseminated grains in cements, breccia clasts,and albite veins. As with the ductile-shear zone styleores, sulfide minerals also comprise <5–6% of the orezones in the breccias.

Almost all gold exists as native gold, with very minorelectrum and gold-bearing tellurides. About 20–30% ofthe gold grains are >0.074 mm in diameter. Shi et al.(1993) divided the auriferous hydrothermal activity atthe Shuangwang deposit into four stages, (1) early py-rite–ankerite–quartz–albite, (2) pyrite–albite–ankerite,(3) pyrite–calcite, and (4) final quartz–tourmaline–py-rite. Although all four stages included deposition of

Fig. 3. a Schematic geological map showing some of the NW-striking gold-bearing breccia bodies hosted by metasedimentaryclastic rocks between the Xiushiya and Wangjialong strike-slipfaults, Shuangwang deposit, Shaanxi province (after Shi et al.1993). The Shuangwang gold mine is located in the no. 4 (IV)breccia body. b Schematic cross sections of the main orebody at themine show that gold mineralization developed in the upper part ofthe breccia zones

c

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gold, the first two are the most important. Li (1993) alsorecognized post-ore stage gypsum–anhydrate veins andfluorite–calcite veins in the deposit.

The presence of nickel-bearing sulfide minerals andthe high platinum and palladium contents of pyritessuggests an ultramafic source for some metals in thedeposit. Although only a few minor post-gold lamp-rophyre dikes are exposed in the mine area, serpenti-nized ultramafic bodies are distributed along theShangdan suture zone, a few kilometers to the north.These rocks have probably interacted to some degreewith the ore fluids prior to gold deposition.

Liba

The Liba deposit was discovered at the end of the1980s and is located at the northwestern end of thegroup of orogenic gold deposits within the central zoneof the western Qinling belt (Fig. 1). Gold mineraliza-tion occurs within and near faults surrounding theporphyritic Zhongchuan biotite–granite batholith(Fig. 4). This intrusive complex, with an exposed areaof 210 km2, is one of six large early Mesozoic granitebatholiths recognized in the central zone. Three ura-nium deposits and dozens of uranium prospects arehosted in NS- and NNE-striking faults, which cut theZhongchuan batholith and its contact zone with thelate Paleozoic country rocks. Gold deposits are hostedin fracture zones that cut the latter Middle Devonian tomiddle Carboniferous metasedimentary rocks to thenortheast (Liba, Loudixia, Ganggouli, Sanrengou,Jiudian, Zhenggouli, and Yawanli deposits) and south(Jinshan, Maquan, Shigoushan, and Miaoshan depos-its) of the batholith (Fig. 4). Liba is the largest of thesedeposits (>50 t Au) in this area.

Liba and adjacent gold deposits are distributed alongthe NW-striking Luoba–Suolonggou fault. It is a high-angle (65–86�), SW-dipping reverse fault that is 60- to100-m-wide and >2,200-m-long. The orebodies occur insecondary faults, adjacent to the Luoba–Suolonggoufault, in spotted siltstones, slates and phyllites of theMiddle Devonian Shujiaba Formation. At the Liba de-posit, a total of 20 orebodies have been identified. Theyare tens to hundreds of meters long, 1- to 30-m-wide,and >250-m-deep. The two largest orebodies (nos. 5and 6) grade 4–5 g/t Au, and contain 80% of the knownresource (Fig. 5). Ore styles are restricted to quartzstockwork systems and altered zones along brittle frac-tures.

Pyrite is the dominant metallic mineral (4–6% of thestockworks), and hosts most of the gold. Minoramounts of pyrrhotite, arsenopyrite chalcopyrite, gale-na, and rutile are also present. Quartz, sericite, andmuscovite, with lesser chlorite, biotite, feldspar, andcarbonate are the main gangue minerals, with kaoliniteand limonite developed in oxidized zones. Gold occursas native gold and as electrum, with fineness of goldranging from 800 to 1,000 (Liu 1994).

Alteration at the Liba deposit comprises mainlypyritization, silicification and sericitization, with minorcarbonatization, chloritization, argillization, biotitiza-tion, and tourmalinization. There is a weak zonation inalteration minerals, from a pyrite–arsenopyrite–sericiteinner zone, to a sericite middle zone and a chlorite outerzone. Three hypogene stages and one supergene stage ofgold mineralization are recognized at the Liba deposit.Stage 1 comprises quartz with minor arsenopyrite, pyriteand apatite. Stage 2 is defined by a gold–pyrite–arsen-opyrite–quartz–sericite assemblage, which is the mainore event. Stage 3 is characterized by a base-metal sul-fides–quartz–calcite–chlorite assemblage that is associ-ated with minor gold deposition. The supergene stageled to the enrichment of gold in oxidized zones. Limo-nite and kaolinite are the dominant minerals in the su-pergene zone, with minor jarosite and gypsum. Limoniteis a useful indicator in the exploration for this type ofgold mineralization in the western Qingling belt (Liu1994).

Jinshan–Maquan–Miaoshan goldfield

The Jinshan–Maquan–Miaoshan goldfield, occurring35 km to the south of the Liba deposit, was discoveredin 1989 and now has a 60 t Au resource delineated inthese three deposits in an area of <30 km2. The resourcehas an average grade of 5.5 g/t Au. The deposits areadjacent to the ENE-striking Zhaoping–Jiziba faultsystem within the hornfels zone of the Zhongchuanbatholith (Fig. 4), notably localized along intersectionsbetween smaller faults. The host rocks for the Jinshandeposit are Middle Devonian phyllites and silty phyllitesof the Xihanshui Formation, whereas the Maquan andMiaoshan deposits are hosted in mid-Carboniferousmicroclastic rocks that include silty slate, spotted slateand siltstone.

Many orebodies consist of disseminated gold inaltered spotted slate and phyllite. This includes orebodyno. 19, the largest such body, which is >1-km-long,3- to 5-m-wide, and continues for more than 300-m-down-dip. In addition, large sheeted veins that areelsewhere atypical of the western Qinling belt, arecharacterized by widths of 5 to 10 m, and locally are aswide as 30 m in some orebodies. The veins have irregularshapes, pinch and swell along strike, and are typicallydiscontinuous. Later brittle faulting has strongly frac-tured the auriferous quartz veins, commonly leading to abrecciated texture (Liu 1994).

Pyrite and arsenopyrite are the main ore minerals inthe goldfield, with minor sphalerite, galena, chalcopy-rite, chalcocite, and bornite. Quartz is the dominantgangue mineral, with subordinate calcite. Most of thegold grains are very fine, and fill fractures in pyrite,arsenopyrite, or quartz, as well as occurring alongthe boundaries of the sulfide minerals. About 85% ofthe gold occurs as native gold and electrum, with theremainder hosted in the crystal lattice of pyrite. Primary

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ore formed in both an early quartz–pyrite–chalcopyrite–arsenopyrite stage and a later, less important quartz–calcite stage. Oxidized ores occur in the upper 50 m ofthe goldfield and are characterized by widespread lim-onite (Liu 1994).

Carlin-like gold deposits of the western Qinling belt

More than 15 disseminated sedimentary rock-hostedgold deposits, commonly referred to as Carlin-like, havebeen discovered in the western Qinling belt since themid-1980s. Eight of these deposits contain total

resources of more than 100 t Au. The similarities be-tween these gold deposits (Li and Peters 1998; this study)and the Carlin-type gold deposits of the western USA(Percival et. al. 1990; Berger and Bagby 1991) include (1)micron-sized gold in arsenical pyrite, (2) Au–As–Sb–Hg–Tl geochemical association, and (3) alteration ofsilty carbonate rock characterized by decalcification,dolomitization, silicification, argillization, and the in-troduction of fine-grained sulfide minerals. Many of theore textures for deposits in both regions are nearlyidentical. Dissolution textures are common and includebrecciated and corroded calcareous clasts within amatrix of hydrothermal mineral phases and residual

Fig. 4. Geological map of theLiba–Jinshan district, Gansuprovince showing the distribu-tion of gold, uranium, and basemetal deposits (modified fromLiu 1994). All gold deposits aredistributed surrounding theZhongchuan granite pluton,whereas the uranium depositsare controlled by the NE- to N-striking faults in or surroundingthe pluton

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insoluble material, such as clay, organic carbon, andiron-sulfides.

A significant difference, however, does exist betweenthe Carlin-like gold deposits of the western Qinlingbelt and those of the western USA. The Chinese de-posits exhibit a strong structural control and are nar-row and steeply-dipping. The size of the depositsdiscovered to date generally does not exceed 60 t Aucontained within less than 20 million t (Mt) of ore.The USA deposits are characterized by a completerange between structural (e.g., Deep Star) and strati-graphic (e.g., Carlin) controls (Christensen 1993). De-posit size exceeds 830 t Au (Post-Goldstrike; Thoreson1993) and deposit tonnage ranges up to 350 Mt of ore(Gold Quarry; Rota 1993). The strong structuralcontrol to the Chinese deposits likely reflects the poorporosity and permeability of relatively unreactive car-bonate, siliciclastic, and metamorphic host rocks, whencompared with the mixed carbonate–siliciclastic li-thologies present in the Carlin vicinity (e.g., silty do-lomite of the Roberts Mountains Formation). The hostrocks to the Chinese deposits lack the transitionalnature of the host rocks to the western USA deposits,which are commonly characterized by silty carbonateor calcareous siltstone.

The disseminated sedimentary rock-hosted gold de-posits of the western Qinling belt cluster into twogroups, which are separated by the Mianlue fault zone.The more extensive northern group occurs in a westwardextension of the southern zone of the western Qinlingbelt. The second group, with the largest Carlin-like de-posit in China (Dongbeizhai), lies in the northeasternpart of the Songpan–Ganzi basin, to the south of thefault. The most significant deposits from each region aredescribed below.

Additionally, scattered deposits to the east of thesetwo groups and close to the Mainlue fault zone, such asJianchaling and Huanglong, are also classified as Carlin-like because they are characterized by only fine-graindisseminated gold. The Jianchaling deposit, however,consists mainly of sub-micron gold–pyrite–arsenicalpyrite–arsenopyrite–orpiment ± cinnabar in a serpen-tinized ultramafic body (Pang and Chen 1993; Viel-reicher et al. 2000). Yang (1996) classified it as an‘‘ophiolite-related gold deposit’’. Because detailed stud-ies of these deposits are lacking, we do not discuss thesefew deposits in the remainder of the paper.

Carlin-like gold deposits in southern zoneof the western Qinling belt

Most Carlin-like deposits in the southern zone of thewestern Qinling belt are distributed along the regionalanticline a few tens of kilometers north of the Mianluefault (Fig. 1). Several deposits, however, including theManaoke and Dashui deposits, are located along theregional fault itself. The ores in this area, roughly be-tween latitude 33�30¢ and 34�00¢, are consistently char-acterized by enrichments in Au, Sb, As, Hg, and Tl, withless common anomalies of W, Cu, Zn, Mo, Se, U, V, P,and/or PGEs (Wang 1994). The Dashui, La’erma,Manaoke, Gongme, Jiuyuan, Zhongqu, and Dingpingdeposits are the larger Carlin-like systems in this belt.Host rocks are mainly partly-calcareous, fine-grainedclastic rock sequences, with rare carbonate strata,probably of Cambrian and Ordovician age, althoughother Paleozoic ages are commonly given for rocks inthe ore-hosting anticline (see Table 1). Whereas themajority of the deposits in this anticlinal structure havemany Carlin-like features, they are also dominantlydistributed along ductile to brittle shear zones. In thislatter aspect, they also partly resemble the turbidite-hosted orogenic lode-gold deposits in Victoria, Australia(Phillips and Hughes 1995; Ramsay et al. 1998). Alongthe Mainlue fault, the large Dashui deposit (50 t Au) ishosted by a Triassic carbonate sequence and appearsmore similar to most recognized Carlin-like deposits.

La’erma

La’erma is a structurally controlled deposit that wasdiscovered in 1985 and has a refractory resource of 23 tAu. The grade of individual orebodies ranges between1.5 to 6 g/t Au, with a general decrease with depth.Locally grades of as much as 10 g/t Au have been noted(Li and Li 1994).

The host rocks for the La’erma deposit consist ofthree units of the Cambrian–Ordovician TaiyangdingGroup (Fig. 6a). The lower unit, which hosts themajority of the orebodies, comprises carbonaceous andsiliceous slate. The upper two units are composed ofcarbonaceous, siliceous, and sericitic slate and silty

Fig. 5. Geological map of the Liba gold deposit, Gansu province,showing gold orebodies within a group of NW-striking fracturezones, which are cut by a post-mineralization NWN-strikingfracture zone (after Liu 1994)

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phyllite. Organic carbon in the carbonaceous units of theTaiyangding Group averages 3.4% and, locally, is asabundant as 14.6% (Li and Li 1994). Although no largegranitoids occur near the La’erma deposit, small maficand felsic dikes are present in the mine area.

La’erma lies along the western end of the axial sur-face of the westerly-plunging Bailongjiang anticline. Thedeposit is hosted within a north-dipping (�60�) group ofshear zones bounded by two dextral strike-slip faults. Atthe deposit-scale, the westerly-striking shears are char-acterized by brittle fractures and brecciation, which host

gold ore. Secondary NE- and NW-striking faults cut thewesterly-trending faults.

More than 20 gold orebodies have been found in theLa’erma deposit. Most orebodies occur along shearzones within an area 800-m-long by 300-m-wide(Fig. 6a). Secondary controls to ore include bed-ding planes, lithological contacts, and anticlinal foldhinges. Individual orebodies are generally tens to hun-dreds of meters long, several to tens of meters wide, andextend as much as 200-m-down-dip (Fig. 6b). Thelargest orebody is 1,000-m-long, locally 35-m-wide, and

Fig. 6. a Geological map andb schematic geological crosssection of the La’erma golddeposit, Gansu province (afterLi and Li 1994). The goldmineralization developedbetween two normal faultsalong the La’erma shear zone.It is hosted in the lowermostunit of the Cambrian–Ordovi-cian Taiyangding Group, whichconsists of carbonaceous andsiliceous slate and silty phyllitewith intercalated sericitic slate

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160-m-deep. The orebodies are geometrically complexand are commonly discontinuous along strike anddown-dip (Li and Li 1994).

Gold mineralization is associated with pervasive sili-cification. Ore-hosting slates are totally replaced bymicrocrystalline quartz (jasperoid) and associated seri-cite. Barite and minor montmorillonite are common inthe silicified rocks. Sulfide minerals within veinlets andbreccia in the altered zones include pyrite, cinnabar,stibnite, realgar, orpiment, marcasite, molybdenite,pyrrhotite, chalcopyrite, sphalerite, galena, and arseno-pyrite. The orebodies average about 3 vol% sulfideminerals. Uranite- and bismuth-bearing mineral phasesare also often present. Native gold occurs within quartz,barite, and, less commonly, stibnite. The gold is gener-ally less than 150 lm in diameter, with 23% of the grainsno larger than 5 lm (Odekirk 1995). The fineness is 899to 949 (Li and Li 1994). Liu et al. (2000) indicate avariety of selenide minerals are often intergrown withthe gold and stibnite.

There is a vertical zonation of metals in the depositfrom gold-rich ores at surface to copper-bearing, lowergold-grade ore at depth. Native gold in association withpervasive silicification, gold in barite stockworks, andgold associated with stibnite occur in the near-surfaceparts of the La’erma deposit. Below this zone, gold,along with quartz, barite, stibnite, and/or cinnabar, isconcentrated in zones of realgar and orpiment stock-works and disseminations. Gold ores that are spatiallyassociated with pyrite, stibnite, and marcasite, in agangue of quartz, calcite, sericite, and barite, occur atlower levels of the deposit. Finally, gold mineralizationin the deepest portion of the deposit contains about0.4% disseminated chalcopyrite, along with quartz,chlorite, pyrite, stibnite, sphalerite, galena, and raremolybdenite (Li and Li 1994).

Dashui

The Dashui deposit, at 3,500–4,000 m in elevation,contains the largest known gold resource in Gansuprovince. Dashui was discovered in 1990, as a result ofthe follow-up of a Au–As–Sb–Hg stream sedimentanomaly from a regional geochemical reconnaissancesurvey. Early mining and heap leaching of high-grade,oxide ore began in 1991, under a joint venture betweenthe No. 3 Team of the Gansu Bureau of Geology andMineral Resources and the local government. A reserveof more than 46 t Au grading 9.9 g/t (with a possiblereserve of >100 t Au) has been defined (Table 1). Thedeposit is a structurally controlled disseminated golddeposit, which is oxidized from the surface to depths ofmore than 300 m (Garwin et al. 1995).

The Dashui deposit is hosted in Middle Triassicshallow marine carbonate rocks and younger igneousdikes. Triassic to Early Jurassic stocks, sills, and dikes ofgranitic to dioritic composition are scattered throughoutthis northern part of the Songpan–Ganzi basin, with

monzodiorite and granodiorite bodies most commonnearest to Dashui. The deposit lies along the southernflank of the Bailongjiang anticline and occurs adjacentto a 20- to 40-m-wide, high-angle, NW-striking reversefault, which is filled by a series of calcite veins andbreccias (Fig. 7a). This zone forms the hanging wall togold mineralization and defines the contact betweenMiddle Triassic limestone and overlying argillaceouslimestone, dolomite, and sandstone in a moderately tosteeply, southwesterly-dipping succession. The limestonehost rock is a massive to poorly-bedded, variably re-crystallized, light to medium gray micrite–wackestone.Minor intercalations of highly altered calcareous silt-stone occur in the eastern part of the deposit. A series ofNNW-striking strike-slip faults, which divide theorebodies at Dashui, post-date magmatism and oreformation.

Steeply SW-dipping, pre-mineral biotite–hornblendegranodiorite porphyry dikes intrude the limestone northof the calcite-filled reverse fault. These intrusions extendfor more than 400 m, are as wide as 70 m, and have beenintersected in drill hole down to depths of �300 m(Fig. 7b). The dikes display fine- to medium-grainedhypidiomorphic and porphyritic textures. Intrusivecontacts are sharp, locally exhibit chilled margins, anddisplay complex breccia textures where adjacent tomineralized limestone. Each of five major zones of dikesat Dashui is spatially associated with gold mineraliza-tion. A much more massive stock-like intrusion in thenorthern portion of the Dashui mine area, which issimilar in composition to the dikes, has been dated byK–Ar methods at 190 Ma (Ren 1999).

The Dashui deposit consists of five W- to N-trending,steeply-dipping ore zones that extend across a fault-controlled belt, which covers an area 2,000 m by 150 m.Presently, ore grades (e.g., ‡5 g/t Au) continue for morethan 40 m beneath the surface, but mineralization isproven to depths of 300 m. Individual orebodies in eachore zone tend to parallel adjacent dikes and might becontrolled by the limestone–igneous rock contacts. Thewidths of these are as great as 60 m, with an average of18 m for the most significant bodies in the deposit. Thelengths of individual orebodies range from 150 to 300 mand they are often discontinuous along strike and down-dip.

Hydrothermal alteration is characterized by twomajor styles and varies according to host rock type.Limestone displays variable intensities of fracture-con-trolled and pervasive silica–hematite alteration. Hema-tite is inferred to have formed as a result of the oxidationof fine-grained pyrite. Alteration phases in limestone,similar to gold deposits along the Carlin trend in Ne-vada, have a general paragenetic sequence of formation

Fig. 7. a Geological map and b schematic geological cross sectionof the Dashui gold deposit, Gansu province (after Garwin et al.1995). The Carlin-like gold deposit is hosted by Triassic carbonatesand Jurassic dikes, along a brecciated, NW-striking reverse fault

c

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of early diagenetic and hydrothermal dolomites, perva-sive silicification by the introduction of microcrystallinequartz, deposition of kaolinite, and late calcite veinand breccia emplacement (McComb 1995). Carbonatedissolution, volume-loss, and the development of dis-solution-related breccias accompanied hydrothermal al-teration (Fig. 8a). Breccia textures include corrodedstylolite-like clast boundaries to variably-dissolved cal-cite and dolomite clasts both within a matrix of quartz,dolomite, hematite, and (or) residual insoluble clays(Fig. 8b). The extent of brecciation typically increaseswith intensity of hydrothermal alteration and amount ofcarbonate dissolution (Garwin et al. 1995). The hematitepervasive silicification and late calcite veins, which are

associated with gold mineralization, represent regionaland deposit-scale prospecting tools.

Granodiorite dikes display argillic (kaolinite) andsilica–hematite alteration styles. Alteration intensity inboth limestone and intrusive rock progressively increaseswith proximity to mineralized intrusion-limestone con-tacts. Visible alteration halos in limestone extend foranywhere from 5 to 100 m away from intrusion margins,whereas haloes in the dikes commonly do not exceed20 m. Wang et al. (1998a) report a Rb–Sr isochron ageof ca. 182 Ma for silica–hematite alteration.

Dissolution breccias are best developed adjacent tointensely altered and mineralized dike margins andinvolve both limestone and intrusive rock. Collapse

Fig. 8. a Hand specimen ofbrecciated limestone, whichcontains angular to sub-angularfragments of recrystallizedlimestone supported in a brec-cia matrix composed of fine-grained quartz, dolomite andhematite. b Photomicrograph(transmitted light, cross nicol)of the hand specimen The sam-ple is a dissolution breccia thatillustrates the embayed andcorroded margins of calciteclasts (stained red). The brecciamatrix consists of hydrothermalquartz, secondary dolomite,hematite, and residual insolubleclays. The hematite and insolu-ble residue are concentratedalong stylolite-like fracturesthat act as the pathways forhydrothermal fluids and disso-lution of the calcite wall rock.Field of view is 2.5 mm, thescale bar is 500 lm

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breccias locally include fragments of granodiorite,which are argillized and less commonly silicified,within a matrix of altered limestone. Collapse brecciasand karst cavities have developed on the micro-scale,and at large scales with individual caverns as much as20 m in diameter.

Gold is disseminated in the altered limestone andgranodiorite dikes. The majority of the ore occurs withinthe limestone and exceeds 3 g/t Au, and high-gradebodies may sometimes exceed 30 g/t in both rock types.Most gold is submicroscopic, with visible gold rarelyobserved as discrete grains (10–35 lm in diameter) alonghematite-coated fractures in high-grade ore. Hematitecomprises 1–5% of the altered rocks in the ore zones.Sulfide minerals are extremely rare and, where present,most often occur as fine-grained pyrite encapsulated inmicrocrystalline quartz.

Carlin-like gold deposits in the northeasternSongpan–Ganzi basin

A southern group of gold deposits occurs along thenortheastern edge of the Songpan–Ganzi basin, which isrepresented by the earlier-described, immense Triassicflysch sequence. The Triassic sedimentary rocks host thegold deposits in the group. Carbonate rocks dominatethe Lower to Middle Triassic sequences, and are locallyintercalated with shale and sandstone. Middle to UpperTriassic stratigraphic sequences consist of interbeddedgravel-bearing sandstone, fine- to coarse-grained sand-stone, siltstone, argillite, and limestone. Dongbeizhai isthe most important of the deposits in this group, withsignificant resources also at Zheboshan and Qiaoqiao-shang. These deposits have Carlin-type affinities, with aAu–As–Sb–Hg–W metal association. A few other golddeposits occur elsewhere in the northeastern part of thebasin (Fig. 1), but these are not Carlin-like systems. TheBaxi deposit, discussed in detail below, appears to be agold-bearing skarn deposit (Luo et al. 1998; Wang et al.1998a; Cao 1999). The Rangtang deposit is associatedwith major shear zones and an adjacent granitoid (Ma1999) and is probably an orogenic gold deposit.

Dongbeizhai

Dongbeizhai is the largest known gold resource inSichuan province and is located in a mountainous areawith surrounding peaks that reach 5,500 m. The depositwas discovered in 1978 by geochemical prospecting. Areserve of more than 52 t Au grading 5.5 g/t Au hasbeen identified, with twice as much gold defined aspossible reserves. Dongbeizhai is a sulfidic-refractory,structurally, controlled deposit, which is hosted by car-bonate and carbon-bearing clastic sedimentary rocks.

The Dongbeizhai deposit is located at the intersectionof regional north–south and east–west trending struc-tural corridors within the Songpan–Ganzi basin. The

stratigraphic sequences surrounding the deposit includeCarboniferous to Lower Permian carbonate rocks andMiddle Triassic black slate and other clastic rocks. Theclastic sequence is carbonaceous and contains 0.2 to0.7% organic carbon (Mao and Li 1994). The two se-quences are separated by the north-trending, steeplywest-dipping Kuashiya fault zone (Fig. 9a). TheKuashiya fault zone contains lenses of hydrothermallyaltered mafic volcanic rocks, which are several meterswide by tens of meters long. The age of the volcanicrocks and their relationship to the adjacent sedimentarysequences are uncertain. However, their presence indi-cates the fault to be a major structural discontinuity.

The deposit is localized along the footwall of theKuashiya fault within the uppermost portion of theMiddle Triassic mudstone and clastic sequence. Hydro-thermal alteration consists of pervasive silicification(jasperoid), which is commonly associated with abun-dant calcite veining, argillic alteration, and the intro-duction of fine-grained arsenical pyrite. Seven majororebodies and 11 smaller bodies have been defined alonga north–south strike-length of 4.5 km. Individual ore-bodies are 320- to 1,360-m-long, 1.4- to 6.2-m-wide(Fig. 9a) and extend from 175- to 700-m-down-dip(Fig. 9b). Average gold grades range from 4.7 to 7.1 g/t,using a 1.0-g/t cut-off.

The majority of the gold in the deposit is contained inbrecciated and silicified, carbonaceous mudstone. Oresare associated with the fine breccia and cataclasite alongthe fault zone, with no significant amount of gold in theunbrecciated wall rocks. Near-surface realgar-rich orepasses into arsenical pyrite-bearing ore at depth.Crosscutting relationships indicate that the deeper orewas deposited in an earlier event relative to the real-gar-rich ore. Gold-bearing zones commonly containarsenical pyrite, arsenopyrite, realgar, stibnite, and (or)scheelite, with minor marcasite, pyrrhotite, tennantite,sphalerite, and chalcopyrite. The gold is sub-micron tomicron size and is generally contained in fine-grainedarsenical pyrite. Electron microprobe analysis of theauriferous pyrite indicates as much as about 10% arse-nic, with good correlation between arsenic and goldconcentrations in studied grains (Wang and Zhou 1994).Visible gold, as much as 40 lm in diameter, occurs in thenear-surface oxide portion of the Dongbeizhai deposit.

Other gold deposit types

Orogenic gold deposits and Carlin-like gold depositscontain most of the gold resource in the western Qinlingbelt. The only other important gold deposit types areplacer accumulations and gold-bearing skarn deposits.The placers are distributed along south-flowing rivers ofthe orogen and have been mostly mined out. The oneimportant gold skarn, Baxi, is located near some of theCarlin-like gold deposits (Fig. 1), but any genetic con-nection between the two gold deposit types is uncertain.

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Placer gold deposits of the western Qinling belt

Placer gold was the major gold mining target in thewestern Qinling belt until the late 1980s when significantorogenic lode and Carlin-like gold deposits, as discussedabove, were discovered. There were more than 50 placergold deposits distributed along rivers that flow from thecentral zone south into the Jialing River, which is amajor branch of the Yangtze River. The Xihanshui andBailongjiang Rivers (Fig. 1), upper tributaries to theJialing River system, were the most important sites ofplacer gold mining in the southern zone of the westernQinling belt and in adjacent parts of the Yangtze craton.Most of these placer deposits have been mined out, withthe most significant having been located near Guangy-uan in the Jialing River system (Fig. 1). They occurdiscontinuously for an additional 150 km to the south ofGuangyuan along this river system. Placer gold depositsare also well-developed along the Peijiang River system,another major branch of the Yangtze River. Theseplacer deposits also continued far to the south within theYangzte craton. Although little studied, their distribu-tion suggests orogenic gold deposits may be widespread

into the Yangtze craton because such deposits are thetypical sources for such placer accumulations.

Baxi gold skarn deposit

The Baxi deposit is located along the Mianlue fault zoneand is 20 km north of the town of Ruo’ergai. It wasdiscovered in the early 1990s by following up streamsediment anomalies (Luo et al. 1998). After detailedexploration using trenches, exploratory adits and dia-mond drilling, a resource of 6. 4 t Au at a grade of 4 g/twas delineated.

The host rocks for the Baxi deposit (Fig. 10) areMiddle Triassic quartzite, quartz sandstone microliticlimestone, and dolomite intercalated with silty slate andcalcic slate in the vicinity of a Mesozoic stock. Contactmetamorphism has altered the limestone to garnet–diopside–wollastonite skarn in the near contact zone,and diopsidic marble distal to the Qierang stock. Theclastic lithologies have been converted to hornfels andquartzite nearest to the intrusion (Cao 1999). The stock,exposed over several square kilometers and wider atdepth, consists of quartz diorite and minor biotite di-orite (Fig. 10). There are more than 20 dikes comprisinggranite porphyry, aplite, monzonite, and syenite in andsurrounding the diorite stock.

Most of the gold orebodies developed along thecontact zones of the diorite stock (Fig. 10). Skarn,

Fig. 9. a Schematic geological plan and b cross section of theDongbeizhai gold deposit, Sichuan province (after Mao and Li1994). The Carlin-like gold deposit occurs along the footwall of theKuashiya fault within fine-grained, carbonaceous Triassic clasticrocks

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quartzite, and marble are the most common host units.The orebodies are grouped into three belts, labeled as I,II, and III from north to south, which strike west andnorthwest. The no. I ore belt is 600-m-long and 2- to 10-m-wide, and contains five distinct orebodies. The no. IIbelt, with two-thirds of the gold resource, is 500-m-long,10- to 100-m-wide, and 200-m-down-dip and comprises22 individual orebodies that are as long as 350 m and asthick as 8 m. The no. III ore belt comprises 10 orebodiesthat are 30- to 83-m-long and 0.7- to 7.5-m-thick.

The ore belts in the Baxi gold deposit, in addition tobeing associated with skarn assemblages, are stronglysilicified and carbonatized, and are commonly brecciat-ed. More than 30 individual skarn zones have beenidentified adjacent to the Qierang diorite. The skarns arecomprised of garnet, diopside, scapolite, actinolite, andepidote, with a garnet- and diopside-dominant skarnassemblage most closely associated with the gold min-eralization. Silicification is represented by quartz stock-works and fine veinlets throughout zones of high goldgrade. Carbonate alteration is mainly post-gold andoccurs as calcite and ankerite veins. Sulfide mineralsrecognized in the gold-bearing skarns include pyrite,chalcopyrite, galena, stibnite, and arsenopyrite, butthese are all relatively minor (Luo et al. 1998).

Timing and processes of gold deposit formationin the western Qinling belt

Geologic relationships and isotopic dates of variablequality, discussed in more detail below, indicate that

almost all of the important gold-forming events in thewestern Qinling belt occurred during the Early andMiddle Jurassic. Unlike the western United States,where orogenic gold deposits in the accreted terranes ofCalifornia formed about 100 million years prior to theCarlin deposits in Nevada, both these types of gold de-posits in central China seem to have formed approxi-mately coevally. Also, unlike North America, thedeposit types were emplaced in a similar tectonic regime,although probably at different crustal levels.

Genesis of orogenic gold deposits

Orogenic gold deposits of the western Qinling region aredistributed almost solely within the central Qinling zone,a late Paleozoic basin that was closed between the col-liding NCC and Yangzte craton. Whereas Late Archeanand Paleoproterozoic metamorphic rocks are variablyexposed in the cratonic blocks to the north and south ofthe collisional orogen, and units of such ages are glob-ally extremely important gold ore hosts, no Precambriangold deposits are yet to be recognized in this part (or anypart, i.e., Zhou et al. 2002, this volume) of China. Inaddition, no Cretaceous (e.g. Yanshanian) orogenic goldlodes are known in the western Qinling belt, as is com-mon to the east in the eastern Qinling belt (Mao et al.2002, this volume) and on the Jiaodong Peninsula (Qiuet al. 2002, this volume). There is obviously little impactfrom Yanshanian orogenesis this far inland from thePacific margin.

The brittle to ductile shear zone-hosted gold depositswithin the central zone of the western Qinling belt arebest classified as orogenic lode gold deposits. They ex-hibit most of the characteristics of such ores as discussedin Groves et al. (1998). The ore fluids of these deposits

Fig. 10. a Schematic geological plan and b cross section of the Baxiskarn type gold deposit, Sichuan province (after Luo et al. 1998).The gold-bearing skarn is developed along the contact betweenMesozoic diorite and Triassic clastic rocks

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are CO2-rich fluids (Li 1993; Shi et al. 1993; Li and Li1994; Zhong and Zhang 1997). Most gold-bearingquartz at the Baguamiao deposit has measured d18Ovalues of about 13–20 per mil (Guo et al. 2000). Thesulfur isotope values (3.8–13.8 per mil) of pyrites fromgold ores in the Shuangwang deposit partly overlap withthose of quartz diorite in the gold district, but are dis-tinctly different from that of the local metasedimentaryhost rocks (–2.1 to –6.6 per mil; Shi et al. 1993). Simi-larly, at the Baguamiao deposit, extremely heavy d34Svalues of 9.5–15.4 per mil characterize gold-related sul-fide minerals (Guo et al. 2000). Such values are amongthe heaviest for any province of orogenic gold depositsand are unlikely to be compatible with an igneous sulfursource. These are more indicative of a sedimentary rocksulfur reservoir existing in some unit(s) at depth. Hy-drothermal carbonates (ankerite) are common in thesegold deposits. The d13C values of –4.5 to –6.3 per miland d18O values of 8.3 to 8.7 per mil of these depositshave been used to indicate a deep possibly mantle originfor fluids (Li et al. 1993; Shi et al. 1993; Zhong andZhang 1997), although other interpretations are alsopossible.

Previous workers have alternatively classified thesegold deposits in the Devonian flysch as Carlin-like (Liand Peters 1998). We find the strong structural controlto the ores, both quartz vein and altered rock types, aswell as the abundant CO2 in the ore forming fluids,relatively coarse-grained nature to some of the gold,lack of decalcification, metamorphic setting, alterationassemblages, and lack of low temperature sulfidemineral assemblage, provide compelling evidenceagainst such a classification. The lack of abundantlarge quartz fissure veins at many of these gold de-posits may contrast somewhat with many orogenicgold districts, but the networks of fine gold-bearingquartz veinlets are common in many significant oro-genic gold systems. Basinal strata trapped betweencolliding cratonic blocks in central Asia similarly hostVariscan gold deposits with this same structural style,e.g., Sukhoi Log (Russia) and Muruntau (Uzbekistan).All these orogenic gold deposits are bulk minabletargets, which is a feature similar to Carlin-like de-posits, yet the minable targets in the former are betterclassified as veinlets and not disseminated ore. Theextensive placer gold deposits in rivers that cut thewestern Qinling belt are also consistent with manyorogenic gold districts, whereas fine-grained gold inCarlin-like deposits is not normally recognized as animportant source for placer gold deposits.

Placing orogenic gold deposit formation into a verydetailed geologic/tectonic framework is hindered by thelarge uncertainty in the available geochronology. Theone certainty is that the deposits formed sometime be-tween about 210 and 170 Ma. A U–Pb isotope date fromBaguamiao yielded an age of 209 Ma (Table 2; Wei et al.1994), a date of 176 Ma by the Rb–Sr isochron methodwas determined for Liba (Table 2; Shao 2000), and40Ar/39Ar dating of feldspar from the Shuangwang de-

posit gave a range of ages between ca. 202 and 198.3 Ma(Table 2; Shi et al. 1993). Questions regarding the pre-cision of these reported ages make it impossible to de-termine whether gold formation was a single episode orcontinuous throughout the Early and Middle Jurassic.Orogenic gold vein formation also partly overlaps thedominant 240–180-Ma period of plutonism within theregion (Table 2). A variety of dating methods suggestthe intermediate intrusions at the Manaoke and Shu-angwang deposits crystallized ca. 215–198 Ma (Table 2;Zhang 1988; Shi et al. 1993). As in many gold districtswithin orogenic belts, we would interpret the overlap inages to be the consequence of both magmatism andhydrothermal fluid flow resulting from thermal pro-cesses during orogenesis.

The available geochronological data allow us to atleast develop a broad regional model for ore genesis inthe central zone of the western Qinling belt. There canbe little doubt that the orogenic gold deposits devel-oped during final stages of closure of the Paleo-Teth-yan Qinling Ocean of Meng and Zhang (1999). Theocean basin likely formed during a post-collisionalrifting, beginning at about 400 Ma, and continuinguntil late in the Paleozoic. The re-initiation of a con-vergent regime may be marked by the Late Carbonif-erous age for regional metamorphism of exposed flyschreported by Meng and Zhang (1999). Subduction ofoceanic crust and overlying sediments was underwayby the beginning of the Triassic, which marked theonset of final suturing between the NCC and Yangtzecraton (Meng and Zhang 1999). Lead isotope signa-tures from the Triassic magmatic arc developed withinthe intermediate sedimentary basin are consistent witha source reflecting underthrust rocks of the Yangtzecraton (Zhang et al. 1997). We would argue that thesesubduction-related processes were also the ultimatecontrol on ore formation, with fluids perhaps beingproduced via prograde metamorphic reactions deepwithin the sedimentary basin or from thermal eventsalong the down-going slab itself. Such fluids wouldhave migrated upward along the major thrusts in andon the margins of the basin, depositing veinlets withinshallower-level, uplifted units.

An obvious question is why there are no recognizedorogenic lode gold deposits in the accreted arc terranesnorth of the Shangdan fault zone. The ca. 480–440 Mavolcanic rocks of the Qinling and Erlangping Groupswere progressively accreted to the margin of the NCC by400 Ma (Zhai et al. 1998) and then subsequently meta-morphosed to greenschist and higher metamorphic fa-cies. However, no gold deposits are recognized withinthe accreted complex or the inboard, adjacent cratonicmargin, despite a short-lived Caledonian period of mi-nor arc magmatism in Late Silurian and Early Devonian(Lerch et al. 1995). Perhaps the relatively short sub-duction episode, with rifting occurring very soon aftercollision during the Early Devonian, was unfavorablefor the relatively massive thermal pulse required forsignificant hydrothermal activity.

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Table

2.Summary

ofisotopicagedata

ofgold

mineralizationandigneousrocks

Nameofgold

deposit

orintrusion

Typeofgold

deposits

orthenames

of

relateddeposits

Tectoniclocation

Measured

rocks/minerals

Ages

(Ma)

Measuredmethods

Data

sources

Dashui

Carlin-like

Songpan–Ganzibasin

Biotitein

granodiorite

237.7±1.7–222.5±2.6

40Ar–

39Ar

Wangetal.1998b

Biotitein

granodiorite

236.5±2.4–223.0±2.8

40Ar–

39Arisochron

Wangetal.1998b

Granodiorite

190.6–190

K–Ar

Ren

1999

Fluid

inclusionsin

jasperoid

181–141

Rb–Srisochron

Wangetal.1998

Lar’erma

Carlin-like

SouthernQinlingzone

Fluid

inclusionsin

quartzin

ores

58.2–40.8

40Ar–39Arisochron

Wang1994

Fluid

inclusionsin

quartzin

ore

49.5–47.3

40Ar–39Ar

Lietal.1994

Ore

117.5–56.8

U–Th–Pb

Dacite

172

K–Ar

Jiuyuan

Carlin-like

SouthernQinlingzone

Interm

ediate

dike

201

K–Ar

Lin

etal.1999

Shijiba

Carlin-like

SouthernQinlingzone

Granodiorite

149.4±4.5

K–Ar

Wangetal.1998b

Baguamiao

Orogenic

CentralQinlingzone

Ore

209

U–Th–Pb,

Singlestages

Weietal.1994

Shuangwang

Orogenic

CentralQinlingzone

Feldsparin

ore

183.09±20.64–168.05±16

40Ar–

39Ar

Shietal.1993;

FanandJin1994

Quartzdiorite

213.5

Rb–Srisochron

Monazite

inquartz

diorite

202

U–Pb

Biotitein

quartzdiorite

198.3

Biotite

Dingping

Carlin-like

SouthernQinlingzone

Dike

214

K–Ar

LiBZetal.1994

Liba

Orogenic

CentralQinlingzone

K-feldspar

176

Rb–Srisochron

Shao2000

Xianggougran-

odiorite,Zhouzhi

county,Shaanxi

NearMa’anqiao

orogenicdeposit

CentralQinlingzone

Granodiorite

200

40Ar–

39Ar

Zhangetal.1988

Lazigougranodiorite,

Diebucounty,Gansu

Norelateddeposit

SouthernQinlingzone

Granodiorite

121.3±3.6

K–Ar

Wangetal.1998b

Xiaojinchang

granodiorite,Wudu

county,Gansu

Norelateddeposit

SouthernQinlingzone

Granodiorite

164.5±4.5

K–Ar

Wangetal.1998b

Pingdinggranodiorite

stock,Zhouqu

county,Gansu

Norelateddeposit

SouthernQinlingzone

Granodiorite

164.1±4.9

K–Ar

Wangetal.1998b

Xiangzhagranodiorite,

Ruo’ergaicounty,

Sichuan

Norelateddeposit

Songpan–Ganzibasin

Granodiorite

211.6±5.4

K–Ar

Wangetal.1998b

Macaowangrano-

diorite,Dangchang

county,Gansu

Norelateddeposit

SouthernQinlingzone

Granodiorite

206.7±6.2

K–Ar

Wangetal.1998b

Baojigranodiorite

Norelateddeposit

NorthernQinlingbelt

Zircon

214–206

U–Pb

Lu1999

Taibaigranodiorite

Norelateddeposit

NorthernQinlingbelt

Wholerock

454

Rb–Srisochron

Lu1999

373

Genesis of Carlin-like ores

Poor geological and geochronological constraints makeconstruction of detailed genetic models for the Carlin-like gold deposits of the western Qinling belt difficult. Asshown by other workers, gold deposits along a 600-kmbelt, from Dashui in the west to Huanglong in the east,as well as a N–S-trending cluster in the northeasterncorner of the Songpan–Ganzi basin (Fig. 1), possessmany features similar to those of the Dian–Qian–Guigold province in southwestern China and the NevadaCarlin gold trend in the USA (Li and Li 1994; Li andPeters 1998; Zhang et al. 1998; Zhou et al. 2001). Thesefeatures are particularly consistent for the gold ores ofthe Songpan–Ganzi basin. Those in anticlinal extensionof the southern zone of the western Qinling belt appearto be more transitional between Carlin-like and struc-turally-controlled orogenic gold deposits, although theDashui deposit (slightly south of the structure) is lessquestionably a Carlin-like deposit. Whereas we prefer toclassify these ores as all Carlin-like at the present time, itis quite possible that when additional data becomeavailable, some of the deposits might be reclassified asorogenic gold deposits.

Evidence for the unequivocal classification of golddeposits in the Songpan–Ganzi basin as Carlin-like in-cludes (1) the low-grade to unmetamorphosed sedimen-tary host rocks, (2) the occurrence of microgranular goldin association with arsenical pyrite, (3) the Au–Hg–Sb–As–W ± U geochemical suite, and (4) the low tempera-ture of ore formation. The ore minerals have a large rangeof sulfur isotope values (d34S=–30 to +30 per mil) andthe d13C values of hydrothermal carbonates from Dong-beizhai vary between –0.1 and –3.2 per mil (Mao and Li1994). The deposits can be no older thanMiddle Triassic,the age of some of the hosting sedimentary rocks, butunfortunately there are no constraints for aminimumage.

The only tectonism in the northeastern part of theSongpan–Ganzi basin was in Late Triassic to EarlyJurassic. This time was characterized by folding ofbasinal strata, widespread emplacement of 210–195 Maplutons, and the thrusting of basin margin sequencesover the adjacent Yangtze craton (Nie et al. 1994). Itseems reasonable to suggest that the gold-forming hy-drothermal events were associated with the tectonism. Ifthis is the case, however, it certainly would imply adifferent tectonic scenario for Carlin-like ore formationhere relative to Nevada. It is now fairly well-acceptedthat most of the Carlin-like ores in Nevada formed inthe middle Tertiary (e.g., Kuehn 1989; Hofstra 1995).This was a period of regional extension in the westernUSA that post-dated convergence-related thrustingalong the craton margin by many tens of millions ofyears. There is no such evidence for later, similar re-gional extension in the Songpan–Ganzi basin and thusCarlin-like hydrothermal systems may be products ofvariable crustal stress regimes.

The other Carlin-like deposits, to the north and eastof the Dongbeizhai deposit area, apparently have a va-

riety of possible hosts – the belt of early Paleozoic sed-imentary rocks trending into the Songpan–Ganzi basin,and platform cover sequences of a variety of ages on thenorthern side of the Yangtze craton. If these are all thesame type of gold deposit, and again we stress that moredata are needed before this can be said with total cer-tainty, then it indicates that favorable stratigraphy willbe of little use in targeting gold resources in Carlin-likesystems in this part of the western Qinling belt.

The Dashui deposit is perhaps the most Carlin-like ofthe gold systems along the anticlinal extension of thesouthern zone into the Songpan–Ganzi basin. Examin-ation of the deposit by one of us (S.G.) indicates hy-drothermal alteration mineral textures and ore-formingprocesses typical of those that have been studied inNevada (Bakken 1990; Berger and Bagby 1991; Kuehnand Rose 1992; Williams 1992). The granodiorite por-phyry dikes at Dashui provided a competency contrastfor fracture-controlled hydrothermal alteration and oredeposition. Ascending sulfidizing fluids were channeledalong dike margins and accessed reactive carbonate wallrock through zones of fracture-enhanced permeability.The deposition of pyrite ± quartz was initiated at thistime and progressed to advanced stages in fracture- anddissolution-related breccia zones adjacent to intrusive-limestone contacts. Submicroscopic gold was depositedalong with pyrite late in the genesis of the deposit.Contemporaneous with the decalcification and silicifi-cation of the limestone, CaCO3 was driven outwardsinto adjacent limestone and dike rock and was depositedas calcite veins marginal to ore. Additional calcite veinsand breccias developed as the hydrothermal systemwaned and collapsed, which disrupted the continuity ofore locally. Subsequent uplift, erosion, and oxidation ofthe deposit formed hematite at the expense of pyrite.

Unlike the Songpan–Ganzi basin deposits, geochro-nology is available for some of these Carlin-like depositsto the north. Biotites in granodiorite at the Dashui de-posit are dated by Ar–Ar at ca. 240–220 Ma (Table 2;Wang et al. 1998b), whereas altered dikes, dated byK–Ar, are ca. 190 Ma (Table 2; Ren 1999) and this maybe close to the actual time of mineralization. Furthersupport for an Early to Middle Jurassic mineralizationage are a range of Rb–Sr isochron ages between 141.0and 181.8 Ma (Table 2) for fluid inclusion waters fromjasper in the gold ore at Dashui and a 182±16 Maisochron age for silica–hematite alteration (Wang et al.1998). The timing of gold mineralization in the nearbyLa’erma deposit might be similar. Zhou and Graham(1996) reported an age of 172 Ma for the La’erma de-posit using K–Ar of dacite. Wang (1994), however, ob-tained ages of ca. 60–40 Ma (Table 2) for the samedeposit based on 40Ar/39Ar of fluid inclusion watersfrom quartz. Wang et al. (1998b) reported Rb–Sr iso-chron ages of 227 and 169 Ma (Table 2) for gold min-eralization in the Gongme deposit, several kilometerseast of the La’erma deposit, with the younger age almostidentical to those from a number of methods for gran-odiorite and felsic dikes in the deposit. Finally, many of

374

dates determined for granitoids throughout the areasouth of the Lixian–Shanyang fault range between ca.210 and 160 Ma and are, therefore, probably part of thesame broad event.

If the fluid inclusion argon dates from La’erma areignored, in large part because of the questionable ana-lytical approach, then the data indicate formation of theCarlin-like ores at about the same time as the orogenicgold deposits to the north. This would imply the Carlin-like ore systems also formed during the early Mesozoicfinal collision between the cratons. The deposits wouldhave formed at higher crustal levels than the orogenicgold deposits to the north of the Lixian–Shanyang fault.Future studies are needed to determine whether theCarlin-like ores formed from distinct hydrothermalsystems, perhaps with a significant meteoric watercomponent, or whether there is a link between hydro-thermal events responsible for these two deposit types assuggested by Phillips and Powell (1993).

Conclusions

The western Qinling belt in central China is a relativelynew and apparently favorable target for the discovery oforogenic and Carlin-like lode gold deposits. Both de-posit types appear to be products of the Triassic finalcollision between the NCC and Yangtze craton. Theores are localized in flysch basins and calcareous turbi-dites that mark the suture between the cratons and theoverlapping eastern edge of the Songpan–Ganzi basin.The orogenic gold deposits developed in the morenorthern parts to the suture, localized within thegreenschist facies deformed flysch units. The Carlin-likedeposits are south of these and are hosted by a variety ofstratigraphic sequences, which are all unmetamor-phosed, or of low metamorphic grade.

The Early to Middle Jurassic orogenic gold depositsare typical of this type of gold deposit worldwide andformed from the fluids generated deep within the flyschbasin itself, perhaps during prograde metamorphism.Ores were deposited coevally with widespread arc mag-matism and the subduction of the leading edge of thenortherly-migrating Yangtze plate. Structural styles,characterized by veinlet networks and massive silicifi-cation, favor bulk minable type gold targets rather thandevelopment of high-grade fissure quartz veins, such asis common at Xiaoqinling and elsewhere on the easternside of the Qinling orogen.

The geochemical and mineralogical characteristics ofthe Carlin-like deposits are all quite similar to those ofdeposits in the Carlin trend, Nevada, USA. These Car-lin-like deposits, along the western edge of the Qinlingorogen, formed at the same time as the orogenic golddeposits a few tens of kilometers to the northeast. Unlikethose in Nevada’s Carlin trend, the Chinese Carlin-likedeposits are entirely structurally controlled and show noobvious temporal association with regional extension.Therefore, the structural and tectonic setting of the

western Qinling Carlin-like deposits, as well as theirspatial/temporal association with the orogenic golddeposits, suggest a possible close genetic link betweenthe two distinct common gold deposit types presentlydefined in the western Qinling belt.

Acknowledgments Colleagues (David Groves in particular) at theCentre for Global Metallogeny (UWA) are thanked for thoughtfuldiscussions, and Z.X. Li and W.W. Guo (UWA) are thanked forproviding information relevant to this paper. The authors aregrateful to Lu Guxian, Lin Wenwei, Zhang Zuoheng, and WangZhiliang (Chinese Academy of Geological Sciences), Luo Yaonan(Sichuan Bureau of Geology, Exploration and Development), NiuBaogui (Institute of Geology, Chinese Academy of GeologicalSciences), and Cao Zhimin (College of Industry and Technology)for their constructive suggestions. We thank Newmont MiningCorporation for the permission to publish company data on theCarlin-like deposits in Gansu and Sichuan Provinces. We are sin-cerely grateful to Noreen Vielreicher, Dana Bove, and MartinHughes for their thorough and constructive reviews. This study wasjointly supported by Major State Basic Research Program ofPeople’s Republic of China (no. G1999043211), China NaturalSciences Foundation (Grant no. 49672116), and Foundation ofFormer Ministry of Geology and Mineral Resources (grantno. 9617). It is also a contribution to IGCP-373 Project.

References

Ames L, Tilton GR, Zhou G (1993) Timing of collision of the Sino-Korean and Yangtse cratons: U–Pb zircon dating of coesite-bearing eclogites. Geology 21:339–342

Ames L, Zhou G, Xiong B (1996) Geochronology and isotopiccharacter of ultrahigh-pressure metamorphism with implica-tions for collision of the Sino-Korean cratons, central China.Tectonics 15:472–489

Avigad D (1995) Exhumation of the Dabie Shan ultra-high-pres-sure rocks and accumulation of the Songpan Ganze flyschsequence, central China: comment. Geology 23:764–765

Bakken BM (1990) Gold mineralization, wallrock alteration andthe geochemical evolution of the hydrothermal system in theMain orebody, Carlin mine, Nevada. PhD Thesis, StanfordUniversity, Stanford California

Berger BR, Bagby WC (1991) The geology and origin of Carlin-type gold deposits. In: Foster RP (ed) Gold metallogeny andexploration. Blackie, Glasgow, pp 210–248

Bruguier O, Lancelot JR, Malavieillre J (1997) U–Pb dating onsingle detrital zircon grains from the Triassic Songpan–Ganziflysch (Central China): provenance and tectonic correlation.Earth Planet Sci Lett 152:217–231

Cao Z (1999) Geological characteristics of the Baxi gold deposit inNou’ergai county, Sichuan province (in Chinese). Unpublisheddata

Christensen OD (1993) Carlin trend geologic overview. In: Chris-tensen OD (ed) Gold deposits of the Carlin Trend, Nevada.Guidebook prepared for Society of Economic Geologists fieldconference, 13–15 April 1993, pp 12–26

Eide E, Liou JG, McWilliams MO (1994) 40Ar/39Ar constraints onhigh and ultrahigh pressure metamorphism, Hubei Province,China. Geology 22:601–604

Ernst WG, Liou JG (1995) Contrasting plate-tectonic styles of theQinling–Dabie–Sulu and Franciscan metamorphic belts. Geol-ogy 23:353–356

Fan S, Jin Q (1994) The Shuangwang gold deposit in Shaanxiprovince. In Liu D, Tan Y, Wang J, Jiang S (eds) ChineseCarlin-type gold deposits (in Chinese). University of NanjingPress, Nanjing, pp 254–285

Garwin SL, Tu H, Zhou X, (1995) Preliminary evaluation of theDashui gold deposit, Gansu Province, China. Newmont Inter-nal Report

375

Gilder SA, Courtillot V (1997) Timing of the North–South Chinacollision from new middle to late Mesozoic paleomagnetic datafrom the North China Block. J Geophys Res 104:15365–15390

Goldfarb RJ, Phillips GN, Nokleberg WJ (1998) Tectonic settingsynorogenic gold deposits of the Pacific Rim. Ore Geol Rev13:185–218

Groves DI, Goldfarb RJ, Gebre-Mariam M, Hagemann SG,Robert F (1998) Orogenic gold deposits: proposed classificationin the context of their crustal distribution and relationship tothe other gold deposit types. Ore Geol Rev 13:7–27

Gu XX (1994) Geochemical characteristics of the Triassic Tethys-turbidites in northwestern Sichuan, China: implications forprovenance and interpretation of the tectonic setting. GeochimCosmochim Acta 58:4615–4631

Guo J, Liu P, Zhang W, Zhu HP, Zhu HZ (2000) Ore-forming andexploration models of the Baguamiao gold deposit, Shaanxiprovince. Acta Geol Sin 74:577–581

Hacker BR, Wang X, Eide EA, Ratschbacher L (1996) The Qin-ling–Dabie ultra-high-pressure collisional orogen. In: Yin A,Harrison M (eds) The tectonic evolution of Asia. CambridgeUniversity Press, Cambridge, pp 345–370

Hart C, Qiu Y, Goldfarb R, Snee L, Miller L, Miller M (2002)Gold deposits of the northern margin of the North China cra-ton: multiple late Paleozoic–Mesozoic mineralizing events.Miner Deposita (in press) DOI 10.1007/s00126-001-0239-2

Hofstra AH (1995) Timing and duration of Carlin-type gold min-eralization in Nevada and Utah– relation to back arc extensionand magmatism (Abstr). Geol Soc Am Abstr Program27(6):329

Hsu K, Wang Q, Li J, Zhou D, Sun Y (1987) Tectonic evolution ofthe Qinling Mountains, China. Eclogae Geol Helvetiae 83:735–752

Kroner A, Compston W, Zhang G, Guo A, Todt W (1988) Ageand tectonic setting of late Archean greenstone–gneiss terrain inHenan Province, China, as revealed by single-grain zircondating. Geology 16:211–215

Kuehn CA (1989) Studies of disseminated gold deposits nearCarlin, Nevada: evidence for a deep geologic setting of oreformation. PhD Thesis, Pennsylvania State University

Kuehn CA, Rose, AW (1992) Geology and geochemistry of wall-rock alteration at the Carlin gold deposit, Nevada. Econ Geol87:1697–1721

Lerch MF, Xue F, Kroner A, Zhang GW, Tod W (1995) A MiddleSilurian–Early Devonian magmatic arc in the Qinling Moun-tains of central China. J Geol 103:437–449

Li BZ, Wang S, Si GQ, Wang FW (1994) Geological characteristicsof Dingping arsenic–gold deposit and genetic model. In: Liu DS(ed) Carlin-type gold deposits in China (in Chinese). NanjingUniversity Press, Nanjing, pp 203–225

Lin L, Zhu L, Zhang M, Zhu D, Liu H (1999) Comparative ex-periments on gold enrichment and mineralization by bacteriaand algae, organic material and lay minerals. Acta Geol Sin73:66–72

Li W, Fang Y, Shi Z, Fan S, Wu X (1993) Metallogenic conditionsof micrograined gold deposits in Eastern Qinling (in Chinese).Geological Publishing House, Beijing

Li W, Jiang X, Meng F, Ju R (1994) Ore-forming condition of themicrogranular disseminated type of gold deposits in the westpart of Qinlin Mts. In: Shenyang Institute of Geology andMineral Resource (eds) Contributions to prospecting direc-tions and methods of main types of gold deposit in China (inChinese). Proceedings of the International Symposium onGold Geology and Exploration held in Shengyang, Liaoning,pp 1–44

Li X (1993) Main geological characteristics and ore-forming factorsof the Dongbeizhai gold deposit in Sichuan. In: Qinling andDaba Mountains Scientific Research Project Office, Ministry ofGeology and Mineral Resources, and Qinling and DabashanGold Deposits Scientific Research Office, Shaanxi Bureau ofGeology and Mineral Resources (eds) Contributions to golddeposits of the Qinling and Daba Mountains (in Chinese).Geological Publishing House, Beijing, pp 176–189

Li X, Yan Z, Lu X (1993) Qinling–Dabie granitoids (in Chinese).Geological Publishing House, Beijing

Li YD, Li YT (1994) Geology and genetic model of the La’ermadisseminated gold deposit, Gansu Province. In: Liu DS (ed)Carlin-type gold deposits in China (in Chinese). Nanjing Uni-versity Press, Nanjing, pp 226–253

Li Z, Peters SG (1998) Comparative geology and geochemistry ofsedimentary rock-hosted (Carlin-type) gold deposits in thePeople’s Republic of China and in Nevada, USA. US Geo-logical Survey Open-File Report 98-466

Liou JG, Zhang RY, Eide EA, Maruyama S, Wang X, Ernst WG(1996) Metamorphism and tectonics of high-P and ultrahigh-Pbelts in Dabie–Sulu regions, eastern central China. In: Yin A,Harrison M (eds) The tectonic evolution of Asia. CambridgeUniversity Press, Cambridge, pp 300–343

Liu D, Tan Y, Wang J, Liu L (1991) Carlin-type gold deposits inChina. In: Ladeira EA (ed) Brazil gold ‘91– the economics,geology, geochemistry, and genesis of gold deposits. Balkema,Rotterdam, pp 89–93

Liu D, Nutman A, Compston W, Wu J, Shen Q (1992) Remnantsof >3800 Ma crust in the Chinese part of the Sino-Koreancraton. Geology 20:339–342

Liu J, Zheng M, Liu J, Su W (2000) Geochemistry of the La’ermaand Qiongmo Au–Se deposits in the western Qinling Moun-tains, China. Ore Geol Rev 17:91–111

Liu M (1994) The ore-hunting indicators and prospecting methodsof ‘‘Liba type’’ gold deposit (in Chinese). Acta Geol Gansu3:79–89

Lu X (1999) Granitoid tectonic map of Qinling belt (in Chinese).Xi’an Cartographic Publishing House, Xi’an

Luo M, He H, Wang Y (1998) Geological characteristics andgenesis of Baxi gold deposit in the Nuo’ergai county, Sichuanprovince (in Chinese). Mineral Deposit 17(Suppl):377–380

Ma R (1999) Metallogenic geological setting and prospecting tar-gets of the Rangtang gold zone, Sichuan (in Chinese). ActaGeol Sichuan 19:46–49

Mao J, Goldfarb R, Zhang Z, Xu W, Qiu YM, Jun D (2002) Golddeposits in the Xiaoqinling–Xiong’ershan region, QinlingMountains central China. Miner Deposita (in press) DOI10.1007/s00126-001-0248-1

Mao Y, Li X (1994) Main geological characteristics of Dongbeizhaigold deposit in Chuan–Shan–Gan gold triangle region. In: LiuD, Tan Y, Wang J, Jiang S (eds) Carlin-like type (micro-grain-disseminated type) gold deposits in China. Press of NanjingUniversity, Nanjing

Mattauer M, Matte P, Malavieille J, Tapponnier P, Maluski H, XuZ, Lun L, Tan Y (1985) Tectonics of the Qinling belt: buildupand evolution of eastern Asia. Nature 317:496–500

McComb MB (1995) Petrographic examination of 32 rock samplesfrom northwest China. Newmont Metallurgical Services Report

Meng Q, Zhang G (1999) Timing of collision of the North andSouth China blocks: controversy and reconciliation. Geology27:123–126

Miller LD, Goldfarb R J, Nie F, Hart CJR, Miller ML, Yang Y,Liu Y (1998) North China gold – a product of multiple orogens.Soc Econ Geol Newslett 33:1–12

Nie S, Yin A, Rowley DB, Jin Y (1994) Exhumation of the DabieShan ultrahigh-pressure rocks and accumulation of the Song-pan–Ganzi flysch sequence, central China. Geology 22:999–1002

Odekirk JR (1995) Characterization of native gold in La’erma,China samples H-1 and H-2. Newmont Metallurgical ServicesReport

Pang CY, Chen MY (1993) Isotopic chronological data in the Ji-anchaling area and their geological significance (in Chinese).Mineral Resour Geol 7:354–360

Percival TJ, Bagby WC, Radtke AS (1990) Physical and chemicalfeatures of precious metal deposits hosted by sedimentary rocksin the western United States. In: Raines GL, Lisle RE, SchaferRW, Wilkenson WH (eds) Geology and ore deposits of theGreat Basin. Geological Society of Nevada, Symposium Pro-ceedings, Reno, pp 11–34

376

Phillips GN, Hughes MJ (1995) Victoria gold: a sleeping giant. SocEcon Geol Newslett 21:1–13

Phillips GN, Powell JK (1993) Link between gold provinces. EconGeol 88:1084–1098

Qiu YM, Gao S, McNaughton NJ, Groves DI, Ling WL (2000)First evidence of >3.2 Ga continental crust in the Yangtzecraton of south China and its implications for Archean crustalevolution and Phanerozoic tectonics. Geology 28:11–14

Qiu YM, Groves DI, McNaughton N, Wang L, Zhou T (2002)Nature, age and tectonic setting of orogenic gold deposits ofthe Jiaodong Peninsula, North China Craton, China. MinerDeposita (in press) DOI 10.1007/s00126-001-0238-3

Ramsay WRH, Bierlein FP, Arne DC, Vandenberg AHM (1998)Turbidite-hosted gold deposits of central Victoria, Australia:their regional setting, mineralizing styles, and some geneticconstraints. Ore Geol Rev 13:131–152

Ren F (1999) Dashui – a high-grade gold deposit in the SouthGansu Province, northwestern China (in Chinese). Unpublishedreport

Ren J, Zhang Z, Niu B, Li Z (1991) Study on Qinling orogenic belt– emerging process of Sino–Korean craton and Yangtze craton(in Chinese). In: Ye L, Qian X, Zhang G (eds) Proceedings ofQinling orogenic belt. Geological Publishing House, Beijing,pp 99–109

Rota, JC (1993) Geology and related studies at the Gold Quarrydeposit, Nevada. In: Christensen OD (ed) Gold deposits of theCarlin trend, Nevada. Guidebook prepared for Society ofEconomic Geologists Field Conference, 13–15 April 1993,pp 67–78

Rowley DB, Xue F, Tucker RD, Peng ZX, Baker J, Davis A (1997)Ages of ultrahigh pressure metamorphism and protolithorthogneisses from the eastern Dabie Shan: U/Pb zircongeochronology. Earth Planet Sci Lett 151:191–203

Shao S (2000) Qinling orogenic belt: its Paleozoic–Mesozoicevolution and metallogenesis. Acta Geol Sin 74:452–457

Shi Z, Liu J, Jin Q (1993) A study of the Shuangwang gold depositrelated to alkali-carbonatite. In: Qinling and Daba MountainsScientific Research Project Office, Ministry of Geology andMineral Resources, and Qinling and Dabashan Gold DepositsScientific Research Office, Shaanxi Bureau of Geology andMineral Resources (eds) Contributions to Gold Deposits of theQinling and Daba Mountains (in Chinese). Geological Pub-lishing House, Beijing, pp 133–146

Thoreson RF (1993) Geology of the Post deposit, Eureka CountyNevada. In: Christensen OD (ed) Gold deposits of the CarlinTrend, Nevada. Guidebook prepared for Society of EconomicGeologists Field Conference, 13–15 April 1993, pp 50–66

Vielreicher RM, Vielreicher NM, Hagemann SG, Jones G (2000)The Jian Cha Ling Ni–Au deposit: Listvenite-hosted, epizonalgold mineralization in the West Qinling Mountains, centralChina. In: Abstracts of the 15th Australian Geological Con-vention, University of Technology, Sydney, 3–7 July, no 59

Wang A, Gao L, Yan S, Hu C (1998) On genesis of the Dashui golddeposit and its distribution regularities (in Chinese). MineralDeposit 17(Suppl):267–270

Wang J (1994) Geochemistry of ore-forming process of carbona-ceous–siliceous–argillaceous rock type gold (uranium) depositsin China (in Chinese). Atomic Energy Press, Beijing

Wang K, Zhou Y (1994) Mineralogy of the Carlin-type Dong-beizhai and Jinya gold deposits, southwestern China. Int GeolRev 36:194–202

Wang LG, Qiu YM, McNaughton NJ, Groves DI, Luo ZK,Huang JZ (1998) Constraints on crustal evolution and goldmetallogeny in the northwestern Jiaodong Peninsula, China,from SHRIMP U–Pb zircon studies of granitoids. Ore GeolRev 13:275–291

Wang P, Chen Y, Pei R (1998a) Regional minerogenetic series, tec-tono-minerogenetic cycles and evolution in the Qinling Orogenicbelt, China (in Chinese). Geological Publishing House, Beijing

Wang P, Xu G, Liu X, Liu J, Dong F, Wu G (1998b) Control ofarc-shape structure in south sub-belt of the Western Quinlingon the hydrothermal deposits (in Chinese). Mineral Deposit17(Suppl):19–22

Wei L, Cao Y, Wang L (1994) Geological characteristics andgenesis analysis of Baguamiao gold deposits, Shaanxi province.In Liu D, Tan Y, Wang J, Jiang S (eds) Chinese Carlin-typegold deposits (in Chinese). University of Nanjing Press, Nanj-ing, pp 286–305

Williams CL (1992) Breccia bodies in the Carlin Trend, Elko andEureka Counties, Nevada: classification, interpretation androles in ore formation, MSc Thesis, Colorado State University,Fort Collins, CO

Xue F, Kroner A, Reischmann T, Lerch MF (1996a) Paleozoic pre-and post-collisional calc-alkaline magmatism in the Qinlingorogenic belt, central China, as documented by zircon ages ongranitoid rocks. J Geol Soc Lond 153:409–417

Xue F, Lerch F, Kroner A, Reischmann T (1996b) Tectonic evo-lution of the East Qinling Mountains, China, in the Paleozoic: areview and a new tectonic model. Tectonophysics 253:271–284

Xue F, Rowley DB, Tucker RD, Peng ZX (1997) U–Pb zircon agesof granitoid rocks in the north Dabie complex, eastern DabieShan, China. J Geol 105:744–753

Yang K (1996) Gold deposits in China: main types and potential.Int Geol Rev 38:1006–1019

Zhai X, Day HW, Hacker BR, You Z (1998) Paleozoic metamor-phism in the Qinling orogen, Tongbai mountains, centralChina. Geology 26:371–374

Zhai Y, Deng J, Li X (1999) Essentials of metallogeny. GeologicalPublishing House, Beijing

Zhang F, Zong J, Ma J (1998) A tentative discussion on the Carlin-type gold deposits in Qinling and related problems. MineralDeposit 17:172–184

Zhang G (1988) Formation and evolution of Qinling orogenic belt(in Chinese). Northwest University Publishing House, Xi’an

Zhang G, Xiang L, Meng Q (1995) The Qinling orogen andintracontinental orogen mechanisms. Episodes 18:36–39

Zhang G, Meng R, Yu Z, Sun Y, Zhou D, Guo A (1996) Orogenicprocess and dynamic characteristics of Qinling orogenic belt(in Chinese). Sci China (Ser D) 26:193–200

Zhang H, Gao S, Zhang B, Luo T, Ling W (1997) Pb isotopes ofgranitoids suggest Devonian accretion of Yangtze (southChina) craton to North China craton. Geology 25:1015–1018

Zhong J, Zhang G (1997) On the genesis of the super-large Bagu-amiao gold deposit in Fengxian County, Shaanxi Province(in Chinese). Acta Geol Sinica 71:150–160

Zhou D, Graham SA (1996) The Songpan–Ganzi complex of theWest Qinling Shan as a Triassic remnant ocean basin. In: YinA, Harrison M (eds) The tectonic evolution of Asia. CambridgeUniversity Press, Cambridge, pp 281–299

Zhou T, Goldfarb RJ, Phillips GN (2002) Tectonics and distribu-tion of gold deposits in China – an overview. Miner Deposita(in press) DOI 10.1007/s00126-001-0237-4

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