0361-0128/01/3318/109-15 $6.00 109

IntroductionOROGENIC or mesothermal lode gold mineralization in theform of gold-bearing quartz vein systems is present in manyaccretionary orogenic belts. Phanerozoic examples of thesevein systems occur in terranes of the Paleozoic-Triassic Tas-man orogen of southeastern Australia, the Jurassic-early Ter-tiary North American Cordilleran orogen from the MotherLode in California, through the gold camps in British Colum-bia, to Nome, Alaska, and the middle to late Tertiary MonteRosa region of the Alpine orogen (Kerrich and Wyman, 1990;Goldfarb et al., 1997; Pettke and Diamond, 1997; Böhlke,1999). The chemistry of the ore-forming fluids, ore mineral-ogy, metal associations, P-T-XCO2 conditions of alteration andmineralization, and the late orogenic timing of these depositsare remarkably similar through time and space from theMesoarchean to the Cenozoic (Goldfarb et al., 1997; Groveset al., 1998; McCuaig and Kerrich, 1998; Kerrich et al., 2000;Ridley and Diamond, 2000; Goldfarb et al., 2001). However,

the ultimate source of the ore-forming fluids remains contro-versial. Proposed fluid sources include (1) granitoid-relatedorthomagmatic solutions (Burrows et al., 1986; Burrows andSpooner, 1987), (2) convecting meteoric water (Nesbitt et al.,1986, 1989), (3) mantle-derived fluids (Colvine et al., 1984;Fyon et al., 1984), and (4) fluids generated by deep de-volatilization of ocean crust and sediments in subduction-ac-cretion complexes (Kerrich and Wyman, 1990; Goldfarb etal., 1991a). The different models vary in terms of their impli-cations for crustal or mantle source reservoirs for the hy-drothermal ore fluids and solutes.

Nitrogen is one potential tracer for determining the sourceof the ore fluids. Ammonium ion (NH+

4) is the most commonform of nitrogen found in rocks, substituting for K+ in potas-sium-bearing silicates (Honma and Itihara, 1981; Bos et al.,1988; Guidotti and Sassi, 1998), and N2 has been recorded influid inclusions in some quartz veins (Bottrell et al., 1988; Or-tega et al., 1991). The isotopic composition of nitrogen haslarge variations in different geologic reservoirs, which makesthe nitrogen isotope system a potentially important tracer for

Metamorphic Origin of Ore-Forming Fluids for Orogenic Gold-Bearing Quartz Vein Systems in the North American Cordillera:

Constraints from a Reconnaissance Study of δ15N, δD, and δ18O

YIEFEI JIA,†

Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan, Canada S7N 5E2, and Re-search School of Earth Sciences, Australian National University, Canberra ACT 0200, Australia

ROBERT KERRICH,Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, Saskatchewan, Canada S7N 5E2

AND RICHARD GOLDFARB

U.S. Geological Survey, Mineral Resources Program, Denver Federal Central, Box 25046, Mail Stop 964, Denver, Colorado 80225

AbstractThe western North American Cordillera hosts a large number of gold-bearing quartz vein systems from the

Mother Lode of southern California, through counterparts in British Columbia and southeastern Alaska, to theKlondike district in central Yukon. These vein systems are structurally controlled by major fault zones, whichare often reactivated terrane-bounding sutures that formed in orogens built during accretion and subductionof terranes along the continental margin of North America. Mineralization ages span mid-Jurassic to early Ter-tiary and encompass much of the evolution of the Cordilleran orogen.

Nitrogen contents and δ15N values of hydrothermal micas from veins are between 130 and 3,500 ppm and1.7 to 5.5 per mil, respectively. These values are consistent with fluids derived from metamorphic dehydrationreactions within the Phanerozoic accretion-subduction complexes, which have δ15N values of 1 to 6 per mil.The δ18O values of gold-bearing vein quartz from different locations in the Cordillera are between 14.6 and22.2 per mil but are uniform for individual vein systems. The δD values of hydrothermal micas are between–110 and –60 per mil. Ore fluids have calculated δ18O values of 8 to 16 per mil and δD values of –65 to –10per mil at an estimated temperature of 300°C; δD values of ore fluids do not show any latitudinal control.These results indicate a deep crustal source for the ore-forming fluids, most likely of metamorphic origin. LowδDH2O values of –120 to –130 per mil for a hydrous muscovite from the Sheba vein in the Klondike district re-flect secondary exchange between recrystallizing mica and meteoric waters.

Collectively, the N, H, and O isotope compositions of ore-related hydrothermal minerals indicate that theformation of these gold-bearing veins involved dilute, aqueous carbonic, and nitrogen-bearing fluids that weregenerated from metamorphic dehydration reactions at deep crustal levels. These data are not consistent witheither mantle-derived fluids or granitoid-related magmatic fluids, nor do they support a model involving deeplycirculated meteoric water.

Economic GeologyVol. 98, 2003, pp. 109–123

† Corresponding author: E-mail, yiefei.jia@anu.edu.au

the origin of terrestrial silicates and volatiles (Clayton, 1981;Javoy, 1997). Hydrothermal potassium-bearing silicates areubiquitous in alteration domains that develop within and/oradjacent to gold-bearing quartz veins. In greenschist faciesterranes muscovite, or Cr muscovite, is the most abundanthydrothermal potassium-bearing silicate, whereas in amphi-bolite facies-hosted deposits biotite is the dominant potas-sium-bearing silicate in the alteration assemblage. Both thedeposits and the alteration minerals formed broadly contem-poraneously with metamorphism of the host terrane (Mc-Cuaig and Kerrich, 1998). Therefore, hydrothermal micas inorogenic lode gold deposits are ideal for analyzing the nitro-gen contents and nitrogen isotope compositions, to constrainthe δ15N of the ore-forming fluid, and in turn the nitrogenisotope composition of the source reservoirs. Reconnaissancestudies on hydrothermal micas from Archean and Paleozoicorogenic lode gold deposits have proven the feasibility ofusing nitrogen isotopes to trace the origin of the ore-formingfluids for orogenic lode gold deposits (Jia and Kerrich, 1999,2000; Jia et al., 2001).

In this study, we present 100 analyses of nitrogen concen-trations and nitrogen isotope data for hydrothermal mus-covites separated from gold-bearing quartz-carbonate veinsfrom the western North American Cordillera. Included arethe Mother Lode of southern California, the Greenwood,Bridge River, Stuart Lake, Cassiar, and Atlin camps in BritishColumbia (BC), the Klondike district, Yukon Territory, andthe Fairbanks and Willow Creek districts of Alaska (Table 1).This new nitrogen isotope database of hydrothermal micas inorogenic lode gold deposits of the western North AmericanCordillera provides new constraints on the origin of the ore-forming fluids.

Hydrogen isotopes have traditionally been used by manyworkers to identify the source of ore fluids (see Taylor, 1997,for a review). The meteoric water model for orogenic gold de-posits was based on an apparent covariation of the δD of bulkdecrepitated fluid inclusions from gold-bearing quartz veinswith the latitudinally controlled variation of present and Ter-tiary meteoric water (Nesbitt et al., 1986; Zhang et al., 1989).Although there is an abundance of oxygen isotope data, onlylimited hydrogen isotope data exist in the literature fromsome individual gold deposits in the North AmericanCordillera, and much of the hydrogen isotope data is from de-crepitated fluid inclusions that may include secondaries (seeBöhlke and Kistler, 1986; Maheux, 1989; Zhang et al., 1989;Goldfarb et al., 1991b). In this study, 13 samples were col-lected from deposits spanning 30° of latitude from Californiato Alaska and tested for possible relationships between the ni-trogen isotope data and any latitudinal variations of δD in asubset of robust hydrothermal micas. These data, togetherwith a compilation of previous data for individual gold de-posits in the western North American Cordillera, are used toinfer potential source reservoirs for the ore-forming fluids.

Characteristics of Gold-Bearing Quartz Veins in the Western North American Cordillera

The geologic settings and characteristics of gold-bearingquartz vein deposits in the western North AmericanCordillera have been well documented. The principal dis-tricts sampled for this study are described in Böhlke and

Kistler (1986), Taylor (1986, 1987), Weir and Kerrick (1987),and Elder and Cashman (1992; the Mother Lode, California);Leitch et al. (1989, 1991; Bridge River); Church (1997;Greenwood); Mad et al. (1990) and Ash (2001; Stuart Lake),Sketchley et al. (1986), Anderson and Hodgson (1989), andNesbitt et al. (1989; Cassiar); Ash et al. (1996) and Ash (2001;Atlin, British Columbia); Nesbitt et al. (1989) and Rushton etal. (1993; Klondike, Yukon Territory); and Goldfarb et al.(1997; Fairbanks and Willow Creek, Alaska). Here we onlygive a brief summary of the geology of these districts.

Gold-bearing quartz-carbonate vein systems in accretedterranes of the western North American Cordillera are re-lated to major fault zones, which are commonly reactivatedterrane-bounding sutures that developed during accretionand subduction of allochthonous terranes along the continen-tal margin. Mineralization ages range from about 190 to 50Ma, although not all are well established (Fig. 1). This timespan covers much of the evolution of the Cordilleran orogen.

Vein-hosting lithologies vary widely and include ultramafic,mafic, and felsic volcanic rocks, pre- and syntectonic intru-sions, and a variety of oceanic, clastic sedimentary rocks(Table 1). The most common types of host rocks are ophioliticslices and associated clastic units, largely siltstone andgraywacke. Nearly all the units hosting the vein systems havebeen metamorphosed at lower to upper greenschist facies.The veins are dominated by quartz, with lesser amounts ofCa-Fe-Mg carbonate minerals, muscovite, chlorite, albite,and scheelite. Pyrite is the dominant sulfide mineral, withvarying amounts of arsenopyrite, pyrrhotite, tellurides, andbase metal sulfide minerals. In the wall rocks adjoining theveins, hydrothermal alteration patterns are very similar toArchean counterparts (Groves et al., 1998; McCuaig and Ker-rich, 1998; Ash, 2001). The most common hydrothermal al-teration associated with these vein systems is characterized byextensive additions of quartz, carbonate, muscovite, and sul-fide minerals. Alteration mineral assemblages appear to becontrolled mainly by the host rocks; for example, muscovite isassociated with veins in felsic igneous or clastic sedimentaryrocks, whereas Cr-bearing mica is associated with ores inmafic or ultramafic rocks.

Samples and Analytical MethodsIn this study, samples of quartz-carbonate veins with hy-

drothermal micas were collected from mines or open pits thatprovide access to unweathered samples in a vein geometryconstrained in three dimensions. They were from 16 locationsfrom nine of the most important gold mining districts in thewestern North American Cordillera. Sample locations andsimple characteristics are presented in Table 1.

Nitrogen

Elemental nitrogen contents and nitrogen isotope ratios ofmuscovite separates were analyzed using the techniques de-scribed by Jia and Kerrich (1999, 2000). Each pure muscovitesample was finely ground to –250 mesh and loaded into a tincapsule in a clean room. Samples were heated to about1,100°C for 10 min to release structural nitrogen (Bebout andFogel, 1992; Boyd et al., 1993) and oxidized by passing thecombustion products through a bed of chromium trioxide at1,000°C, using a helium carrier gas. Gases were then passed

110 JIA ET AL.

0361-0128/98/000/000-00 $6.00 110

δ15N, δD, AND δ18O OF CORDILLERAN GOLD-QUARTZ VEINS 111

0361-0128/98/000/000-00 $6.00 111

TAB

LE

1. S

umm

ary

of th

e C

hara

cter

istic

s of

Qua

rtz-

Car

bona

te V

ein

Syst

ems

Sam

pled

in th

e W

este

rn N

orth

Am

eric

an C

ordi

llera

Dis

tric

t/Ve

in s

yste

ms/

Vein

loca

tion

Vein

min

eral

Ve

in g

eom

etry

/Te

cton

ostr

atig

raph

ic

Hos

t roc

k ag

e,Ve

in fo

rmat

ion

Gra

nito

ids

Sour

ces

cam

pde

posi

tL

at (

N)

Lon

g (w

)as

sem

blag

eho

st s

truc

ture

terr

ane

litho

logy

(Ma)

(Ma)

Eas

t-ce

ntra

l Ala

ska

Fai

rban

ksC

hris

tina

65°

04' 1

47°

21'

Qua

rtz,

mus

covi

te,

Stee

ply

dipp

ing

Yuko

n-Ta

nana

Ear

ly P

aleo

zoic

92

–85

95–9

01

chlo

rite

, ank

erite

, ve

inle

ts o

r ve

ins

30 c

m

quar

tzite

, Lat

e py

rite

with

min

or

to 1

.5 m

wid

e in

Pa

leoz

oic

schi

st, a

nd

sulfi

des

exte

nsio

nal z

one

mid

-Cre

tace

ous

dior

iteSo

uth-

cent

ral A

lask

aW

illow

Cre

ekF

ern

min

e61

°39

' 14

9°15

'Q

uart

z, m

usco

vite

,Ve

ins

are

near

ver

tical

Pe

nins

ular

L

ate

Pale

ozoi

c sc

hist

66

79–6

61

chlo

rite

, ank

erite

, in

a s

erie

s of

obl

ique

-(W

rang

ellia

an

d L

ate

Cre

tace

ous

pyri

te w

ith m

inor

sl

ip s

truc

ture

sco

mpo

site

terr

ane)

tona

lite

sulfi

des

Wes

t-ce

ntra

l Yuk

on T

erri

tory

Klo

ndik

e di

stri

ctSh

eba

63°

53'

138°

56'

Qua

rtz,

mus

covi

te,

Stee

ply

dipp

ing

vein

sYu

kon-

Tana

naM

id-P

aleo

zoic

-Ear

ly

140–

130

?2

chlo

rite

, cal

cite

, 50

cm

to 2

m w

ide

in

Mes

ozoi

c m

eta-

pyri

te w

ith m

inor

br

ittle

, ext

ensi

onal

zon

ese

dim

enta

ry a

nd

gale

naig

neou

s ro

cks

Nor

ther

nmos

t Bri

tish

Col

umbi

aA

tlin

(1)

Gol

dsta

r 59

°34

' 13

3°42

' Q

uart

z, C

r St

eepl

y di

ppin

g ve

inle

ts

Cac

he C

reek

Lat

e Pa

leoz

oic-

Ear

ly

172–

170

Mid

-Jur

assi

c3,

4(2

) A

nna

59°

33'

133°

37'

mus

covi

te, f

erro

an-

or v

eins

15

cm to

3.5

m

Mes

ozoi

c m

eta-

F

outh

of J

uly

(3)

Surp

rise

59

°31

' 13

3°28

' m

agne

site

, pyr

ite

wid

e in

bri

ttle

faul

t zon

esse

dim

enta

ry, m

afic

and

ba

thol

ith(4

) M

ckee

Cre

ek59

°27

' 13

3°33

' w

ith m

inor

oth

er

ultr

amaf

ic r

ocks

sulfi

des

Nor

ther

n B

ritis

h C

olum

bia

Cas

siar

(1)

Boo

mer

ang

59°

12'

129°

41'

Qua

rtz,

mus

covi

te,

Vein

s ar

e st

eep

to

Sylv

este

r al

loch

ton

Dev

onia

n-E

arly

Tri

assi

c14

0–13

0M

id-

5–7

(2)

Pete

59°

09'

129°

40'

anke

ritic

car

bona

tes,

vert

ical

, gen

eral

ly 1

to

(par

t of t

he S

lide

met

ased

imen

tary

, C

reta

ceou

s py

rite

with

min

or

2 m

wid

e, in

thru

st

Mou

ntai

n te

rran

e)vo

lcan

ic, a

nd u

ltram

afic

C

assi

ar

othe

r su

lfide

szo

nes

rock

sba

thol

ith

ca. 1

00C

entr

al B

ritis

h C

olum

bia

Stua

rt L

ake

belt

Snow

bird

54°

27'

124°

30'

Qua

rtz,

Cr

Vein

lets

15

to 3

0 cm

C

ache

Cre

ekL

ate

Pale

ozoi

c-E

arly

16

5–16

2M

id-J

uras

sic

4, 8

mus

covi

te, f

erro

an-

wid

e di

ppin

g 40

°to

50°

Mes

ozoi

c m

eta-

165–

162

mag

nesi

te, p

yrite

no

rthe

ast i

n br

ittle

se

dim

enta

ry, a

nd

with

min

or o

ther

fa

rult

zone

ultr

amaf

ic r

ocks

sulfi

des

Sout

hwes

tern

Bri

tish

Col

umbi

aB

ridg

e R

iver

(1)

Bra

lorn

e50

°46

' 12

2°49

' Q

uart

z, C

r St

eepl

y di

ppin

g en

(1

) B

ridg

e R

iver

L

ate

Pale

ozoi

c-E

arly

91

–86

Lat

e 9,

10

(2)

Pion

eer

50°

45'

122°

46'

mus

covi

te, a

nker

itic

eche

lon

vein

s 0.

1 to

(2

) C

adw

alle

rM

esoz

oic

(1)

Bra

lorn

e C

reta

ceou

s ca

rbon

ates

, pyr

ite

10 m

wid

e in

bri

ttle

-di

orite

A

lbiti

te d

ikes

w

ith m

inor

oth

er

duct

ile s

hear

zon

es(2

) C

adw

alle

r gr

eens

tone

91–8

6su

lfide

sSo

uthe

rnm

ost B

ritis

h C

olum

bia

Gre

enw

ood

(1)

Impe

rial

49°

07'

118°

59'

Qua

rtz,

Cr

Stee

ply

dipp

ing

vein

lets

Q

uesn

ellia

Pale

ozoi

c-M

esoz

oic

(?)

Jura

ssic

-

11(2

) R

iver

side

49°

06'

118°

58'

mus

covi

te, f

erro

an-

or v

eins

, 5 c

m to

2 m

in

met

aultr

amaf

ic, m

afic

, C

reta

ceou

s m

agne

site

, pyr

itew

idth

and

sedi

men

tary

roc

ksN

elso

n pl

uton

Sout

hern

Cal

iforn

iaM

othe

r L

ode

(1)

Car

son

37°

58'

120°

25"

Qua

rtz,

Cr

Stee

ply

dipp

ing

vein

sSi

erra

Nev

ada

Pale

ozoi

c-M

esoz

oic

147–

144

Mes

ozoi

c-12

–14

(2)

Cou

lterv

ille

37°

43'

120°

12'

mus

covi

te, M

g in

rev

erse

faul

tfo

othi

lls m

etam

orph

ic

met

ased

imen

tary

, 12

5–11

0 (?

)C

reta

ceou

s ca

lcite

, mag

nesi

te,

com

plex

volc

anic

, and

ultr

amfic

Si

erra

Nev

ada

pyri

tero

cks

bath

olith

Sour

ces:

1 =

Gol

dfar

b et

al.

(199

7), 2

= R

usht

on e

t al.

(199

3), 3

= A

sh e

t al.

(199

6), 4

= A

sh (

2001

), 5

= Sk

etch

ley

et a

l. (1

986)

, 6 =

And

erso

n an

d H

odgs

on (1

989)

, 7 =

Dri

ver

et a

l. (2

000)

, 8 =

Mad

uet

al.

(199

0), 9

= L

eitc

h et

al.

(198

9), 1

0 =

Lei

tch

et a

l. (1

991)

, 11

= C

hurc

h (1

997)

, 12

= B

öhlk

e an

d K

istle

r (1

986)

, 13

= L

ande

feld

(19

88),

14 =

Eld

er a

nd C

ashm

an (

1992

)

through a second furnace containing copper at 600°C, whereexcess oxygen was absorbed and nitrogen oxides reduced toelemental nitrogen. Elemental nitrogen concentrations wereobtained from each sample based on system calibration usingknown standards. Analysis of N isotopes on muscovite sepa-rates was conducted using a high-precision, continuous flowisotope ratio mass spectrometer (CF-IRMS) at the Soil Sci-ence Laboratory, University of Saskatchewan. Analytical re-producibilities were ca. ± 0.3 per mil (generally ≤0.3‰ for n≥ 3) for δ15N. The long-term reproducibility for internationalnitrogen isotope standard materials in the laboratory is 0.54 ±0.07 per mil for IAEA-N1 (n = 15, accepted value 0.53‰),20.34 ± 0.08 per mil for IAEA-N2 (n = 10, accepted value

20.41‰), and 5.15 ± 0.21 per mil for the internal laboratorystandard material BLN.SOIL (n = 20, accepted value5.15‰). Ten replicate analyses of the muscovite mineral sep-arate sample CD11-21-1 yielded a mean δ15N value of 3.43(1σ = 0.06‰). Isotope data are reported in standard δ nota-tion relative to atmospheric N2.

Oxygen and hydrogen

Oxygen isotope compositions were determined for 13 se-lected samples using conventional procedures; pure quartzseparates were reacted with bromine BrF5, followed by quan-titative conversion to CO2 (Clayton and Mayeda, 1963). Hy-drogen isotope analyses of 11 selected muscovite separates

112 JIA ET AL.

0361-0128/98/000/000-00 $6.00 112

Alexander

Cassiar

Cache Creek

Bridge River

Chugach

Kootenay

Quesnellia

Stikine

Wrangellia

Yukon-Tanana

Older passivemargin rocks

Slide Mountain

Denali fault system

Tintina fault System

San Andreas fault

DFS:

TFS:

SAF:

Gold Mining Camp

Fairweather-Queen Charlotte faultsFQF:

500 km

North AmericanMargin

Terranes

Craton

U.S.A

Canada

U.S.A

U.S.A

Canad

a

Mexico

49o

32o

Coast B

atholith

Coast R

anges

N

Eastern ed

ge of Cord

illeran Orogen

DFS TFS

FQF

SAF

Accretionary P

rism

Accretionary P

rism

Gold Mining Camps

1. Fairbanks 92-85 Ma

2. Willow Creek 66 Ma

3. Juneau 56-53 Ma

4. Klondike 140-130 Ma

5. Atlin 172-170 Ma

6. Snowbird 165-162 Ma

7. Cassiar 140-130 Ma

9. Bridge River 91-86 Ma

10. Coquihalla (?)

8. Cariboo 140 Ma

12. Alleghany 147 Ma ?

13. Mother Lode 144 Ma ?

13

12

10

8

5

7

4

1

3

6

2

11

11. Greenwood (?)

Sierra Nevada foothills

60o

9

FIG. 1. Distributions of synorogenic gold deposits in the western North American Cordillera. Various terranes are gener-alized from Coney (1989), Wheeler and McFeely (1991), and Monger (1993). Sources for the ages of mineralization in thedifferent districts are indicated in Table 1.

were performed using the uranium technique of Bigeleisen etal. (1952). A Finnigan Mat Delta mass spectrometer was usedfor oxygen in CO2 at the Isotope Laboratory, University ofSaskatchewan, and a Finnigan Mat 252 mass spectrometer atQueens University was used for hydrogen isotopes on mus-covite. Analytical reproducibilities were ±0.2 per mil for δ18Oand ±2.0 per mil for δD. Isotope data are reported in stan-dard δ notation relative to the Vienna SMOW standard forhydrogen and oxygen.

Isotopic Composition of Hydrothermal Minerals

Nitrogen isotope compositions of muscovite

Elemental nitrogen concentrations and δ15N values of hy-drothermal micas from 16 gold-bearing quartz vein systems in

nine mining camps of the western North American Cordilleraare relatively uniform. There is a narrow range within eachvein system, where δ15N typically varies by less than ±0.3 permil, and values between deposits of different mining campstypically overlap (Fig. 2, Table 2). This is well illustrated inthe results from the Christina (Fairbanks) and Fern mine(Willow Creek) vein systems of Alaska, which have mean δ15Nvalues of 5.8 and 5.5 per mil and elemental nitrogen contentsranging from 390 to 401 and 256 to 274 ppm, respectively. Inthe Sheba vein, Klondike district of the Yukon, six muscoviteseparates from quartz veins have a range of δ15N values be-tween 1.6 and 1.8 per mil and elemental nitrogen contents260 and 280 ppm.

In the Cassiar mining camp of northern British Columbiasamples from the Pete vein system (Cr-bearing muscovite)

δ15N, δD, AND δ18O OF CORDILLERAN GOLD-QUARTZ VEINS 113

0361-0128/98/000/000-00 $6.00 113

1 2 3 4 65100

1000

5000

N (

ppm

)

A

15N (‰)

Christina

Atlin

Fern Mine

Cassiar

Klondike

Stuart Lake

Bridge River

Greenwood

Mother Lode

-10 -5 0 5 10 15 20 25

Phanerozoic Au-quartz veinsin the western N.A.Cordillera

10

100

1000

Mantle derived rocks

Organic materials

S-type graniteMetamorphic rocks

Archean Au-quartz veins in Canadaand Western Australia

B

15N (‰)

N (

ppm

)

FIG. 2. A. The N content and δ15N values of hydrothermal muscovite separates from the western North AmericanCordillera quartz vein systems. B. Data compared to those from Archean volcanic- and plutonic rock-dominated terranes inCanada and Western Australia (Jia and Kerrich, 1999, 2000). Fields for rock reservoirs: Organic materials from Peters et al.(1978), Williams et al. (1995), and Ader et al. (1998); metamorphic rocks from Haendel et al. (1986) and Bebout and Fogel(1992); granites from Boyd et al. (1993); mantle-derived rocks from Javoy et al. (1984), Boyd et al. (1987, 1992), Javoy andPineau (1991), Boyd and Pillinger (1994), Marty (1995), Cartigny et al. (1997, 1998), and Marty and Humbert (1997).

and Boomerang vein (white muscovite), which are located 16km apart possess mean δ15N values of 1.9 ± 0.2 (1σ; n = 9) to2.1 ± 0.1 per mil (1σ; n = 6), respectively. Similarly, in theAtlin mining camp, quartz vein systems at the Mckee Creek,Surprise, Goldstar, and Anna deposits spread over about 150km2 and have mean δ15N of 4.5 ± 0.9 per mil (n = 22). For the

Bridge River and Greenwood camps, and the Mother Lodemining camp, more than 1,000 km farther south, the meanδ15N values are 2.9 ± 0.9 (1σ; n = 22), 3.2 ± 0.6 (1σ; n = 9),and 2.7 ± 0.4 per mil (1σ; n = 16), respectively. In summary,at the continent scale, from the Mother Lode in California toFairbanks, Alaska, the total range of δ15N is only 1.6 to 6.1 per

114 JIA ET AL.

0361-0128/98/000/000-00 $6.00 114

TABLE 2. N Contents and δ15N of Mica Separates from Quartz-Carbonate Vein Systems in the Western North American Cordillera

Location/ Sample Analyzed N content δ15N (‰) Location/ Sample Analyzed N content δ15N (‰)vein system no. mineral (ppm) mean ±1σ vein system no. mineral (ppm) mean ±1σ

Fairbanks, east-central Alaska 5.5 ± 0.28Christina Chr-1 Muscovite 394 5.9

Chr-2 Muscovite 390 5.4Chr-3 Muscovite 401 6.1

Willow Creek, south-central Alaska 5.5 ± 0.35Fern mine Fern-1 Muscovite 274 5.8

Fern-2 Muscovite 260 5.5Fern-3 Muscovite 256 5.1

Klondike, Yukon 1.7 ± 0.08Sheba mine SH-1-1 Muscovite 275 1.6

SH-1-2 Muscovite 270 1.6SH-2-1 Muscovite 280 1.8SH-2-2 Muscovite 280 1.7SH-3-1 Muscovite 270 1.7SH-3-2 Muscovite 260 1.7

Atlin Camp, northernmost British Columbia 4.7 ± 0.87Mckee Creek CAS89.4.1A Cr muscovite 1946 4.6

CAS89.4.1B Cr muscovite 1929 4.8CAS89.4.1C Cr muscovite 1963 4.6CAS89.4.1D Cr muscovite 1926 4.4CAS89.4.1-1 Cr muscovite 1965 4.9CAS89.4.1-2 Cr muscovite 1947 4.7CAS89.4.1-3 Cr muscovite 1981 4.9CAS89.4.1-4 Cr muscovite 1947 4.8

Surprise CAS89.14.2.3-1 Cr muscovite 786 5.8CAS89.14.2.3-2 Cr muscovite 768 5.7CAS89.14.2.3-3 Cr muscovite 767 5.3CAS89.14.2.3-5 Cr muscovite 799 5.6CAS89.14.2.3-6 Cr muscovite 787 5.7CAS89.14.2.3-7 Cr muscovite 786 5.3

Goldstar CAS89.05.02 Cr muscovite 330 3.3CAS89.05.03 Cr muscovite 322 3.2CAS89.05.04 Cr muscovite 326 3.0CAS89.05.05 Cr muscovite 338 4.2CAS89.05.06 Cr muscovite 329 3.3CAS89.05.07 Cr muscovite 333 3.4

Anna CAS89.01.01 Cr muscovite 848 4.3CAS89.01.02 Cr muscovite 827 4.1

Cassiar Camp, northern British Columbina 2.0 ± 0.15Pete PETE3-2-1 Cr muscovite 1616 1.9

PETE3-2-2 Cr muscovite 1666 1.8PETE3-2-3 Cr muscovite 1660 1.8PETE3-1-1 Cr muscovite 2325 2.2PETE3-1-2 Cr muscovite 2664 1.7PETE3-1-3 Cr muscovite 2542 2.1PETE3-1-4 Cr muscovite 2566 2.2PETE3-3-2 Cr muscovite 1635 1.9PETE3-3-3 Cr muscovite 1692 1.7

Boomerang BV-1 Muscovite 743 2.1BV-2 Muscovite 740 2.0BV-3 Muscovite 745 1.9BV-4 Muscovite 741 2.0BV-5 Muscovite 750 2.1BV-6 Muscovite 744 2.2

Stuart Lake, central British Columbia 1.7 ± 0.06Snowbird CAS89.41.1-1 Cr muscovite 3466 1.8

CAS89.41.1-3 Cr muscovite 3434 1.6CAS89.41.1-4 Cr muscovite 3497 1.7CAS89.41.1-6 Cr muscovite 3472 1.7

Bridge River Camp, southwestern British Columbia 2.6 ± 0.90Bralorne mine CAS91.61-1 Cr muscovite 3336 2.0

CAS91.61-2 Cr muscovite 3303 2.0CAS91.61-3 Cr muscovite 3345 2.1CAS91.61-5 Cr muscovite 3368 2.0CAS91.61-6 Cr muscovite 3341 2.3CAS91.61-7 Cr muscovite 3368 2.5CAS91.62-1 Cr muscovite 3255 2.4CAS91.62-3 Cr muscovite 3310 2.2CAS91.62-4 Cr muscovite 3276 2.2CAS91.61-6 Cr muscovite 3331 2.4CAS91.64B Cr muscovite 2573 2.7CAS91.64C Cr muscovite 2593 2.8CAS91.64D Cr muscovite 2579 3.0CAS91.64-1 Cr muscovite 2473 3.1CAS91.64-2 Cr muscovite 2592 2.8CAS91.64-3 Cr muscovite 2609 2.3CAS91.64-4 Cr muscovite 2597 2.9

Pioneer CAS91.66-1 Cr muscovite 930 4.3CAS91.66-2 Cr muscovite 963 4.6CAS91.66-3 Cr muscovite 960 4.7CAS91.66-5 Cr muscovite 977 4.7CAS91.66-6 Cr muscovite 971 4.2

Greenwood, southen British Columbia 3.0 ± 0.60Imperial CAS91.40A1 Cr muscovite 129 2.7

CAS91.40A2 Cr muscovite 131 3.0CAS91.40A3 Cr muscovite 124 2.6CAS91.40A4 Cr muscovite 131 2.8CAS91.40A5 Cr muscovite 131 2.2

Riverside RS-1 Cr muscovite 148 3.8RS-2 Cr muscovite 132 3.7RS-3 Cr muscovite 132 3.5RS-4 Cr muscovite 128 4.0

Mother Lode, southern California 2.7 ± 0.45Carson Hill CH21 Cr muscovite 850 3.0

CH22 Cr muscovite 844 3.2CH23 Cr muscovite 834 2.7CH24 Cr muscovite 837 2.8CH25 Cr muscovite 835 2.6CH26 Cr muscovite 851 2.6CH27 Cr muscovite 832 2.3

Coulterville CT41 Cr muscovite 740 3.4CT42 Cr muscovite 733 3.5CT43 Cr muscovite 734 2.8CT44 Cr muscovite 733 2.3CT45 Cr muscovite 738 2.0CT46 Cr muscovite 729 2.0CT47 Cr muscovite 748 2.8CT48 Cr muscovite 750 2.5CT49 Cr muscovite 745 2.3

mil, with a mean of 3.0 per mil, and elemental nitrogen con-tents span 130 to 3,500 ppm, with a mean of 1,535 ppm (Fig.2, Table 2).

Oxygen and hydrogen isotope compositions of silicates

The range of δ18O values for vein quartz samples collectedand analyzed during this study is 14.6 to 22.2 per mil withinthe limitations of the dataset. There is also uniformity in theδ18O values in individual mining camps (Table 3). Three sam-ples from the Carson Hill and Coulterville deposits in south-ern California have δ18O values between 16.5 and 18.6 permil. Similar isotopic homogeneity of vein quartz is noted inthe Bridge River, Cassiar, and Atlin mining camps, wheremean δ18O values of vein quartz are 18.0, 17.0, and 21.7 permil respectively. For the Sheba vein system, Klondike district,three samples give δ18O values of 14.6 to 15.1 per mil (Table3).

The majority of muscovites are characterized by a narrowrange of δD values from –60 to –110 per mil (Table 3). Twosamples (CH2 and CT4) collected from the Carson Hill andCoulterville veins in the southern Mother Lode (lat 37° N)both yield δD values of –65 per mil. One sample from theBridge River camp in southern British Columbia (lat 50° N)possesses a δD value of –60 per mil. Two samples from theBoomerang vein in the Cassiar camp of northern British Co-lumbia (lat 59° N) yield δD values of –95 per mil, and in theAtlin camp three samples from different vein locations yieldδD values ranging from –66 to –112 per mil. Three samplesfrom the Sheba vein in the Klondike district (lat 63° N) haveδD values ranging from –161 to –172 per mil.

Discussion

Elemental nitrogen concentration and N isotope characteristics

The nitrogen concentrations and nitrogen isotope ratios forhydrothermal micas from the gold-bearing vein systems of

the western North American Cordillera are not consistentwith mantle-derived fluids. Mantle nitrogen concentrationsand isotope compositions have been determined from bothmidocean ridge basalts and from fibrous diamonds in Zaire byJavoy et al. (1984), Javoy and Pineau (1991), and Marty (1995)and extended to a worldwide sampling basis by Boyd et al.(1987, 1992). Their results show that nitrogen contents inmantle-derived materials are very low (<1–2 ppm), and thatδ15N values are negative (–8.7 up to –1.7‰) with a mode of–6 to –5 per mil (Table 4). Studies of fibrous diamonds haveshown that mantle nitrogen appears to be isotopically homo-geneous. The characteristics of the hydrothermal micas aredistinct from mantle materials both in terms of more en-riched δ15N values and high elemental nitrogen contents (Fig.2, Table 2).

The data for hydrothermal micas are also inconsistent withorthomagmatic fluids evolved from a crystallizing granitoid.Boyd et al. (1993) studied granites in southwestern Englandthat have δ15N values between 8.4 and 10.2 per mil (two out-liers of 5.1 and 7.0‰). Granitic rocks, worldwide, also havelow elemental nitrogen contents of 21 to 27 ppm (Table 4;Wlotzka, 1972; Hall, 1999). Collectively, nitrogen isotopecompositions of hydrothermal muscovites from the NorthAmerican Cordillera are depleted in 15N relative to graniticrocks, and their elemental nitrogen contents are higher.

A role for meteoric water in the formation of the mus-covite cannot be ruled out on the basis of the nitrogen iso-tope composition of the hydrothermal micas in the gold-bearing quartz vein systems. Global nitrogen isotope valuesof 4.4 ± 2.0 per mil (n = 263; Owens, 1987) of meteoric wateroverlap with micas in these gold deposits. However, the ele-mental nitrogen contents of meteoric water are very low—<2ηmole (Table 4; Homes et al., 1998)—and in geothermal flu-ids are 0.6 to 2 ηmole (Crittenden, 1981), whereas muchhigher N2 concentrations have been observed and measuredin fluid inclusions from orogenic gold deposits. For example,fluid inclusions in vein quartz of the Dolgellau gold belt innorth Wales contain 0.19 to 0.27 mol percent N2 (Bottrelland Miller, 1990), and significant amounts of N2 in the ore-forming fluids have also been measured from gold depositsin Alaska (Goldfarb et al., 1997) and the Central and NorthDeborah gold mines at Bendigo, Australia (Jia et al., 2000).In crustal metamorphic fluids in orogenic belts, N2 is a mainform of nitrogen, having been reported from a variety offluid inclusion studies, including 1.52 to 55.36 mol percent atnorth Wales (Bottrell et al., 1988), 0.6 to 99.0 mol percent inthe Bastogne (Darimont et al., 1988), and 9.6 to 77.4 molpercent at Mari Rosa (Ortega et al., 1991). Furthermore, inorogenic gold deposits there is clear field evidence, in theform of horizontal veins dilated vertically, for the lithostaticto superlithostatic fluid pressures, ruling out deeply convect-ing meteoric water for which Pfluid ≈ 1/3 Plithostatic (Kerrich andAllison, 1978; Sibson et al., 1988; Kerrich, 1989). In sum-mary, elemental nitrogen contents are generally higher influid inclusions from lode gold deposits than in geothermalfluids. Even if nitrogen contents do not provide a definitivedistinction between meteoric and metamorphic origins ofthe ore-forming fluids, meteoric water can be ruled out fromconsiderations both of hydrodynamics and isotopic shifts ofδD and δ18O.

δ15N, δD, AND δ18O OF CORDILLERAN GOLD-QUARTZ VEINS 115

0361-0128/98/000/000-00 $6.00 115

TABLE 3. Oxygen and Hydrogen Isotope Data from Gold-Bearing Quartz Veins

δ18O (‰) δD (‰)Vein location Sample no. Quartz Muscovite

Klondike SH-1 15.1 –161SH-2 14.9 –168SH-3 14.6 –172

Atlin CAS89.14.2.3 21.7 –110CAS89.05 21.4 –66CAS89.01 22.2 –112

Cassiar BV-1 17.1 –95BV-4 16.9 –98

Bridge River CAS91.66 17.8 –60CAS91.661 18.1

Mother Lode CH1 18.6CH2 16.5 –65CH21 16.9 –62CT4 17.6 –65

1 Duplicate sample

Elemental nitrogen contents and δ15N values of gold de-posits in the western North American Cordillera are consis-tent with those reported for metasedimentary rocks in theCatalina Schist subduction zone complex of California, whereelemental concentrations of nitrogen are 60 to 2,100 ppm andwhole-rock δ15N values range from 1.6 to 6.0 per mil (n = 123;Bebout and Fogel, 1992; Bebout, 1997), similar to averagePhanerozoic crust (Table 4; Haendel et al., 1986; Williams etal., 1995; Kao and Liu, 2000). They are also comparable todata for the turbidite-hosted Paleozoic quartz-carbonate veinsystems of the Bendigo-Ballarat region in the Tasman orogenof southeastern Australia, where elemental nitrogen concen-trations in muscovite are 652 to 895 ppm and δ15N values are2.8 to 4.5 per mil (Jia et al., 2001).

The geochemical behavior of nitrogen during formation ofgold-bearing quartz veins has not been examined in detail sofar. According to Bottrell and Miller (1990) in a study of blackshale-hosted quartz-bearing vein gold deposits of northWales, leaching of NH+

4 from host rocks by fluids derivedfrom metamorphic dehydration is the most likely source of ni-trogen in the ore fluid. The thermochemical constraints onthe behavior of nitrogen species (NH+

4 and N2) in the fluidsand their transport and deposition during mineralization arecontrolled by pH and fO2 (Bottrell and Miler, 1990, and refer-ences therein). Although the nitrogen content of the hy-drothermal vein micas appears to generally reflect the con-centration of nitrogen in the source rocks, there could be a

number of other factors that can influence the nitrogen con-tent of a hydrothermal mica that are not directly related tothe abundance of nitrogen in the source.

Rock-fluid fractionation

There is no significant nitrogen isotope fractionation be-tween rock (NH+

4) and fluid (N2) during metamorphic dehy-dration. Bebout and Fogel (1992) empirically evaluated fluid-rock isotope fractionation of N2-NH+

4 during devolatilizationof metasedimentary rocks of the Catalina schist belt by pro-gressive metamorphism, using a Rayleigh distillation model,based on direct measurement of nitrogen isotope ratios ofwhole-rock powder. They obtained δ15N of 2.2 ± 0.6 per mil(632 ± 185 ppm N) in lowest grade rocks (300°C) and 4.3 ±0.9 per mil (138 ± 76 ppm N) for high-grade rocks (600ºC).They calculated fluid-rock (N2- NH+

4) nitrogen isotope frac-tionations of –1.5 ± 1 per mil with the Rayleigh distillationequation at temperatures ranging from 350° to 600°C. Ex-perimental studies on metamorphism of sedimentary kerogenshow that although the elemental nitrogen content inmetasedimentary rocks decreases during metamorphism, theisotopic composition does not change up to 600°C (Williamset al., 1995; Ader et al., 1998). Studies by Jia and Kerrich(1999, 2000) on hydrothermal micas in Archean orogenicgold-bearing quartz vein systems, formed during metamor-phism over a range from subgreenschist to amphibolite facies,also show that elemental nitrogen contents of the micas

116 JIA ET AL.

0361-0128/98/000/000-00 $6.00 116

TABLE 4. Summary of N Contents and N Isotope Compositions in Various Geologic Reservoirs

Reservoirs/ N content δ15N (‰) δ15N (‰)component (ppm) range mean ±1σ Observations References

Mantle-derived materialsMidocean ridge basalts 36 –1.7 to –8.7 –5.0 Fresh basalts 1, 2Midocean ridge basalts 1 to 2 –1. 0 to 6.4 –5.0 Fresh basalts 3, 4Most diamonds 2 to 40 0 to –26 –5.0 P-type diamond 5Most diamonds –1.1 to –10.1 –5.0 E-type diamond 6

Granitic rocksGranites 21 to 27 +5.1 to +10.2 S-type granite 7-9

Organic materialsTerrestrial and aquatic plants –4.4 ± 1.2 Organic compounds 10Terrestrial leaf litter –3.8 ± 0.2 Organic compounds 11Chlorin in sapropels –5.0 ± 0.4 Organic compounds 12Living phytoplankton –6.4 ± 1.4 Organic compounds 12

Marine sedimentary rocksMarine sediments +2.4 to +9.9 Kerogen 13Marine sediments 100 to 2800 3.1 ± 0.3 Kerogen 14Terrestrial sediments +2.7 to +5.1 4.0 ± 0.8 Kerogen 10, 15

Metamorphic rocksMetamorphic rocks 100s to 1000s +3.2 to +7.8 Phanerozoic 16Metasubduction complex 100 to 1100 +1.0 to +6.0 Phanerozoic 17, 18Metamorphic rocks 10s to 100s +11.8 to +17.3 Archean 19

Meteoric waterMeteoric water 2 ηmol 4.4 ± 2.0 Global meteoric H2O 20, 21

Geothermal systemsGeothermal fluids 0.6 to 2 ηmole Geothermal fluids 22

AtmosphereAtmosphere 78 (%) 0 Definition 23

References: 1 = Boyd et al. (1987), 2 = Javoy and Pineau (1991), 3 = Marty (1995), 4 = Marty and Humbert (1997), 5 = Cartigny et al. (1997), 6 = Car-tigny et al. (1998), 7 = Boyd et al. (1993), 8 = Hall (1999), 9 = Wlotzka (1972), 10 = Kao and Liu (2000), 11 = Nadelhoffer and Fry (1988), 12 = Sachs andRepeta (1999), 13 = Peters et al. (1978), 14 = Williams et al. (1995), 15 = Ader et al. (1998), 16 = Haendel et al. (1986), 17 = Bebout and Fogel (1992), 18 =Bebout (1997), 19 = Jia and Kerrich (2000), 20 = Owens (1987), 21 = Homes et al. (1998), 22 = Crittenden (1981), 23 = Hoering (1955)

decrease but the isotopic composition does not change signif-icantly with increasing metamorphic grade. Consequently,the nitrogen isotope composition of N2 in fluids is close tothat of the source rock reservoir.

Secular variation of δ15N

Archean and Phanerozoic orogenic gold vein systems havesimilar characteristics and typically are considered to be prod-ucts of the same type of hydrodynamic system (e.g., Kerrichand Wyman, 1990; Groves et al., 1998). However, the resultsfrom the western North American Cordillera veins are dis-tinct from their Late Archean counterparts in Canada andWestern Australia, which are characterized by relatively lownitrogen concentrations of 20 to 200 ppm but higher δ15N val-ues of 10 to 24 per mil (Jia and Kerrich, 1999, 2000).

Here, we propose that there are variations in the crustalabundance of nitrogen and δ15N values through geologic timedue to progressive sequestering of atmospheric N2 and its cy-cling in the evolving atmosphere-crust-mantle systems.Archean crust had a high median δ15N value of 16 per mil andan average crustal abundance of 30 ppm nitrogen, whereasthe Phanerozoic is characterized by low δ15N values with amedian of 3 per mil and an average crustal abundance ofabout 100 ppm nitrogen (Table 4, and references therein).Micas in orogenic gold deposits reflect the secular trendsinasmuch as the ore-forming fluids sample average crust. Inan earlier compilation, Haendel et al. (1986) showed a trendfrom high nitrogen concentration and low δ15N in greenschistfacies metamorphic rocks to low nitrogen concentration buthigh δ15N in amphibolite and granulite facies terranes. Thistrend was originally interpreted to be due to the loss of nitro-gen and 15N-depleted fluids during progressive metamorphicdehydration. However, the lower grade rocks in this data set

are Phanerozoic, whereas the higher grade rocks are Precam-brian, suggesting that secular variations similar to those de-scribed above may account for the observed trends.

δ18O and δD of the ore-forming fluid

Fluid inclusion studies show that vein-forming fluids fromthe Mother Lode belt, California, the Bralorne mine, and theStuart Lake and Cassiar districts in British Columbia, and theKlondike district, Yukon Territory, generally have low salinity(1–6 wt % NaCl equiv), with varying mole fractions of CO2ranging from 5 to 15 percent. These veins formed at temper-atures between 220° and 400°C, under pressures of 70 to 300MPa, with emplacement depths estimated from about 3 to 12km (Böhlke and Kistler, 1986; Weir and Kerrick, 1987; Gold-farb et al., 1989, 1991b, 1997; Madu et al., 1990; Leitch et al.,1991; Rushton et al., 1993). Accordingly, δ18O values of orefluids in equilibrium with vein quartz were calculated usingthe quartz-water fractionation equation of Matsuhisa et al.(1979), assuming vein formation at 300°C. The δD values ofore fluids in equilibrium with vein muscovite were also esti-mated using extrapolation of water-muscovite fractionationfactors (Suzuoki and Epstein, 1976) down to 300°C, indicat-ing a 40 per mil fractionation.

The calculated δ18OH2O and δDH2O for three samples fromthe Carson Hill and Coulterville deposits in the southernMother Lode are between 9 to 12 and –20 to –15 per mil, re-spectively, which fall within the ranges of δ18OH2O = 8 to 14per mil and δDH2O = –50 to –10 per mil from previous inves-tigations in the district (Fig. 3, Table 5; Kistler and Silberman,1983; Böhlke and Kistler, 1986; Taylor, 1986, 1987). Two sam-ples from Bridge River, British Columbia’s largest gold min-ing camp, give δ18OH2O of 11 to 12 per mil and δDH2O of –15per mil. These results are consistent with those of Maheux

δ15N, δD, AND δ18O OF CORDILLERAN GOLD-QUARTZ VEINS 117

0361-0128/98/000/000-00 $6.00 117

30

40

50

60

70

10 15

A

Alleghany district

Klondike

CassiarAtlin

Bridge River

Mother Lode

Stuart Lake

Lat

itude

18O (‰)

-20-40-60-100-120

Lat

itude

D (‰)

B

* * * *

-140-160

(1)

** * *(2)

* * **

* * * *

(3)

(4)

(5)

(6)

* Fluid Inclusions 30

40

50

60

70

FIG. 3. Ranges of calculated δ18O (A) and δD (B) values of ore fluids plotted with latitude (data source from Table 5).Note: Closed bars represent this study, open bars represent previous studies from Böhlke and Kistler (1986), Taylor (1986,1987), Maheux (1989), Nesbitt et al. (1989), Madu et al. (1990), Goldfarb et al. (1991b), Leitch et al. (1991), and Rushton etal. (1993). All data from silicates, excepting bulk decrepitation of fluid inclusions with star symbols: (1) Fairview and OroFino (Zhang et al., 1989), (2) Bridge River (Nesbitt et al., 1989), (3) Stuart Lake (Madu et al., 1990), (4) Juneau (Goldfarbet al., 1991b), (5) Cassiar (Nesbitt et al., 1989), (6) Klondike (Rushton et al., 1993).

118 JIA ET AL.

0361-0128/98/000/000-00 $6.00 118

TAB

LE

5. O

xyge

n an

d H

ydro

gen

Isot

ope

Com

posi

tions

of Q

uart

z-C

arbo

nate

Vei

ns in

the

Wes

tern

Nor

th A

mer

ican

Cor

dille

ra a

nd C

ount

erpa

rts

Wor

ldw

ide

Gol

d pr

ovin

ce/

δ18 O

quar

tz (

‰)1

δ18 O

ore

flui

d (‰

)2δD

ore

flui

d (‰

)2R

efer

ence

sdi

stri

ctVe

in lo

catio

nR

ange

Med

ian

±st

d de

vT

(°C

)R

ange

Ran

ge

Cor

dille

raJu

neau

gol

d be

ltJu

neau

15.2

to 2

0.8

225

~ 37

57

to 1

3–3

5 to

–15

2

Klo

ndik

e, Y

ukon

Ter

rito

rySh

eba

14.6

to 1

5.1

14.9

±0.

25 (

3)7

to 8

–130

to –

120

114

.7 to

15.

115

.0 ±

0.2

(4)

323

±18

8.9

±0.

63

Atli

n, n

orth

ernm

ost B

CSu

peri

se, G

olds

tar,

21.4

to 2

2.2

21.7

±0.

4 (3

)13

to 1

6–6

5 to

–20

1an

d A

nna

Cas

siar

, nor

ther

n B

CB

oom

eran

g16

.9 to

17.

110

to 1

1–5

5 to

–50

1Vo

llaug

and

oth

ers

14.3

to 1

9.2

16.9

±1.

3 (1

8)25

0 ~

300

4

Stua

rt L

ake,

cen

tral

BC

Snow

bird

21.0

to 2

4.2

22.7

±1.

2 (8

)21

0 ~

260

12 to

15

5

Bri

dge

Riv

er, s

outh

ern

BC

Pion

eer

17.8

to 1

8.1

11 to

12

–15

1B

ralo

rne

and

Pion

eer

17.1

to 1

9.4

18.4

±0.

8 (2

2)23

0 ~

350

10 to

13

–38

±18

6, 7

Mot

her

Lod

e, C

alifo

rnia

C

arso

n an

d C

oulte

rvill

e16

.5 to

18.

617

.6 ±

0.8

(5)

9 to

12

–20

to –

151

Oro

Ric

o an

d M

cAlp

ine

15.0

to 1

7.5

17.1

±0.

3 (2

4)30

06

to 1

18

Alle

ghan

y, C

alifo

rnia

Ori

enta

l17

.3 to

19.

425

0 ~

325

8 to

15

–50

to –

109

Tasm

an o

roge

nic

belt

Ben

digo

, Aus

tral

iaC

entr

al a

nd N

orth

Deb

orah

14.4

to 1

7.2

16.3

±0.

7 (2

0)35

0 ±

258

to 1

1–3

7 to

–17

10

Hill

End

gol

d fie

ld, A

ustr

alia

Hill

End

gol

d fie

ld15

.2 to

17.

116

.3 ±

0.5

(20)

420

8 to

12

–49

to –

3611

Bir

imia

n gr

eens

tone

bel

tA

shan

ti, W

est A

fric

aA

shan

ti go

ld b

elt

12.8

to 1

5.6

14.9

±0.

7 (1

4)40

0 ±

509

to 1

2–5

3 to

–37

12

Supe

rior

Pro

vinc

e of

Can

ada

Abi

tibi b

elt

Hol

linge

r–M

cInt

ype,

Dom

e12

.5 to

15.

022

0 ~

450

6 to

11

–80

to –

2013

Yilg

arn

crat

on, W

. Aus

tral

iaN

orse

man

-Wilu

na b

elt

Kal

goor

lie a

nd N

orse

man

11.4

to 1

3.4

220

~ 50

05

to 9

–40

to –

1014

1 D

ata

are

repo

rted

as

med

ian

one

stan

dard

dev

iatio

n, fo

llow

ed b

y nu

mbe

r of

det

erm

inat

ions

in p

aren

thes

es2T

heδ1

8 O v

alue

s for

vei

n-fo

rmin

g flu

id w

ere

calc

ulat

ed fr

om q

uart

z-w

ater

equ

ilibr

ium

eqa

tion

of M

atsu

hisa

et a

l. (1

979)

and

from

mus

covi

te-w

ater

frac

tiona

tion

fact

ors o

f Suz

uoki

and

Eps

tein

(197

6)us

ing

fluid

incl

uisi

on h

omog

eniz

atio

n te

mpe

ratu

re (

Th)

= 3

00°C

Ref

eren

ces:

1 =

this

stu

dy, 2

= G

oldf

arb

et a

l. (1

991b

), 3

= R

usht

on e

t al.

(199

3), 4

= N

esbi

tt e

t al.

(198

9), 5

= M

adu

et a

l. (1

990)

, 6 =

Lei

tch

et a

l. (1

991)

, 7 =

Mah

eux

(198

9), 8

= W

eir

and

Ker

rick

(198

7), 9

= B

öhlk

e an

d K

istle

r (1

986)

, 10

= Ji

a et

al.

(200

1), 1

1 =

Lu

et a

l. (1

996)

, 12

= O

bert

hür

et a

l. (1

996)

, 13

= K

erri

ch (

1987

), 14

= G

oldi

ng e

t al.

(198

9)

(1989) and Leitch et al. (1991) who showed that the calcu-lated δ18O and δD values of hydrothermal fluids in equilib-rium with quartz and sericites from many of the deposits atBridge River were 10 to 13 and –38 ± 18 per mil, respectively(Fig. 3, Table 5). Two samples of ore fluids from the Cassiardistrict give δ18O and δD values of 10 to 11 per mil and –55± 5 per mil, and three samples from the Atlin camp yield 13to 16 and –65 to –20 per mil. Three muscovite separates fromthe Sheba vein in the Klondike district have δD values of–170 to –160 per mil (Table 3) and thus probably formedfrom a fluid of about –120 to –130 per mil, a composition de-pleted relative to those characteristics of the other vein micas.

The isotopic composition of the ore-forming fluid for theMother Lode belt and Bridge River, Cassiar, and Atlin goldcamps clusters between δ18O values of 8 and 14 per mil andδD values of –65 and –10 per mil, with vein precipitation at300°C. These values are consistent with estimates for othergold-bearing vein systems elsewhere within the westernNorth American Cordillera (see Table 5, and referencestherein). They are also similar to δ18OH2O values of 8 to 12 permil and δD values of –53 to –17 per mil for other metasedi-mentary rock-hosted gold deposits worldwide (Table 5; Lu etal., 1996; Oberthür et al., 1996; Jia et al., 2001). The range ofδ18OH2O values overlaps with but tends to be higher overallthan δ18OH2O values of 6 to 11 per mil obtained for volcanic-hosted Neoarchean orogenic gold deposits (Table 5; Kerrich,1987; Golding et al., 1989; de Ronde et al., 1992; McCuaigand Kerrich, 1998). The minor difference may reflect slightlyhigher formation temperatures of the Archean lodes and/orevolution of metamorphic fluids in greenstone belts withlower bulk δ18O than for Phanerozoic metasedimentary rocksequences.

The total range in δ18O of 15 to 22 per mil for vein quartzfor all mining districts, collectively spanning over 30° latitudein the western North American Cordillera, is typical for veinquartz from orogenic lode gold metallogenic provinces of allages from Archean to Cenozoic (Table 5; δ18O = 12–22‰;Böhlke and Kistler, 1986; Taylor, 1986, 1987; Curti, 1987;Kerrich, 1987; Golding et al., 1989; Goldfarb et al., 1991b; deRonde et al., 1992; Oberthür et al., 1996; Jia et al., 2001). Thishas been interpreted to reflect the isotopic homogeneity ofthe hydrothermal ore fluids and the similar temperatures ofore formation (McCuaig and Kerrich, 1998; Ridley and Dia-mond, 2000). In contrast, epithermal gold deposits are char-acterized by variable δ18O quartz values, which reflect vari-able degrees of water-rock interaction over a range oftemperatures (see Taylor, 1997, for a review).

Nesbitt et al. (1986, 1989) proposed a model of deep circu-lation of meteoric water along transcurrent faults under con-ditions of low water/rock ratios for Cordilleran lode gold de-posits. This model is based primarily on the observations thatδDH2O values obtained by decrepitating bulk fluid inclusionsfrom some vein quartz were depleted (<–100‰) and appar-ently latitudinally dependent. However, the calculated δDH2Ovalues of ore fluids based on robust silicates from the MotherLode, southern California, to the Atlin and Cassiar in north-ern British Columbia, are neither depleted (–65 to –10‰),nor show any latitudinal control, but rather are suggestive ofmetamorphic fluid sources (Fig. 3, Table 5). It is most likelythat low δD values from bulk extraction of fluid inclusions in

some deposits (Nesbitt et al., 1986, 1989) reflect dominantlysecondary inclusions formed in the presence of meteoricwater during uplift of the deposits (Taylor, 1986, 1987; Pick-thorn et al., 1987; Goldfarb et al., 1991a; McCuaig and Ker-rich, 1998).

Meteoric paleowaters in north British Columbia and YukonTerritory are estimated to have δD values of about –140 permil and δ18O values of about –19 per mil (Taylor 1997). Con-sequently, δ18O in a meteoric ore fluid would have to shift bymore than 27 per mil, from –19 per mil to observed values of+8 per mil, by fluid-rock interaction at low water/rock ratios(< 0.1) at 300°C within sedimentary rock-dominant se-quences of the Cordilleran gold districts. A shift of 27 per milin δ18O would be accompanied by large positive shifts in δD,and the primary meteoric water signature would be lost (Ker-rich, 1987). Furthermore, under such a situation, much of thedescending water will rehydrate metamorphic mineralswithin the uplifting and cooling metamorphic terrane. Theonly way to avoid this is to assume that meteoric fluids werestrongly channeled during downward flow, then pervasivelyinteracted with rock with shifting isotope compositions, andfinally were channeled back into narrow structural conduitsduring upward flow. It is difficult, however, to imagine condi-tions, which could consistently lead to such a mechanism offluid flow (Goldfarb et al., 1993). Further, it seems unlikelythat all orogenic gold vein-forming fluids in the Cordillera, aswell as those from elsewhere in the world, could be shiftedfrom variably 18O-depleted meteoric water values dependingon latitude to a much narrower range of δ18O values of 8 to 10per mil (Kerrich, 1989).

An additional complexity in the meteoric water model forCordilleran deposits is constraining the latitude at the timethe deposits formed and distance from the paleo-Pacificocean, given the allochthonous character of the host terranes.Latitude and distance from the ocean are the two factors thatprimarily control the present-day δD of meteoric water onthe North American continent (Taylor, 1997). Cordillerangold provinces from the Mother Lode in southern California,through deposits in the Canadian Cordillera and southeasternAlaska, to Fairbanks, Alaska, and Klondike, Yukon, are ofJurassic to Cenozoic ages (147–53 Ma). From paleomagneticand geologic data these allochthonous terranes have trans-lated along the western margin of North America before orafter the deposits formed. At 100 to 90 Ma, the Interior do-main comprising much of interior British Columbia, centralYukon, and eastern and central Alaska was situated at the lat-itude of northern California. The Coast domain, includingsoutheastern Alaska, much of the Coast Ranges and islands ofBritish Columbia, and the Coast Cascade Mountains of Wash-ington, was situated at latitude similar to northern Mexico.Subsequently, both domains moved northward about 3,000km, reaching their present locations before 45 Ma (Fig. 4;Irving et al., 1995, 1996; Wynne et al., 1995; Ward et al.,1997).

Anomalous δD values of –160 to –170 per mil for mus-covite from the Sheba vein in the Klondike camp are lowcompared to those from other vein systems analyzed in thewestern North American Cordillera (Fig. 3, Table 3). How-ever, as pointed out by Taylor (1986, 1987) and Taylor et al.(1991), hydrothermal micas associated with gold veins in

δ15N, δD, AND δ18O OF CORDILLERAN GOLD-QUARTZ VEINS 119

0361-0128/98/000/000-00 $6.00 119

British Columbia and the Yukon Territory may be character-ized by a range of isotopically primary, enriched, and sec-ondary, depleted values. Our petrographic study of thesemicas from the Sheba vein clearly shows recrystallization.The compositions of these micas are characterized by rela-tively higher H2O contents of 7 to 13 wt percent and low K2Ocontents of 5 to 6 wt percent, with high Si/Al ratios, com-pared to those analyzed from the Mother Lode, BridgeRiver, Cassiar, and Atlin mining camps, with low H2O con-tents of 3.95 to 6.42 percent and high K2O contents of 10.07

to 11.30 wt percent, with low Si/Al ratios (Jia, 2002). Accord-ingly, depleted δD values in the Sheba vein are best inter-preted as reflecting retrograde isotopic exchange accompany-ing compositional change during regional uplift betweenoriginally D-enriched micas and depleted meteoric water.

ConclusionsDetailed studies of the stable isotope systematics (N, H,

and O) of hydrothermal quartz vein systems from differentmining camps in the western North American Cordillera,

120 JIA ET AL.

0361-0128/98/000/000-00 $6.00 120

60

55

49

42

32

U.S.AMexico

U.S.A

Canada

U.S.A

Tintina faultsystem

thrust belt

Eastern limitof Cordilleran

batholithIdaho

Klamathorogen

Nevadabatholith

Sierra

blockSalinian

Peninsular Rangesbatholith

VancouverIsland

BajaCalifornia

San Andreasfault

Denali faultsystem Can

ada

70

60

50

40

30

Canad

aU.S.A

CanadaU.S.A

U.S.AMexico

Intra-Quesnelliafault

batholithIdaho

Nevadabatholith

Sierra

blockSalinian

Peninsular Rangesbatholith

VancouverIsland

BajaBritish Columbia

Baja BritishColumbia fault

Creraceous plutonic belts

Intermontane Superterrane

Coast Mountains orogen

BA

Insular Superterrane

Franciscan Complex

Great Valley Group

Pre-CretaceousKlamath-Sierran terranes

Gold districts

Fairbanks

Willow Creek

Juneau Atlin (170)

Polaris-Taku (63)

Cariboo

Bridge River(91-86)

Greenwood

Mother Lode

(92-77)

(66)

(56-53)

(140)

(147-144)

thrust belt

Eastern limitof Cordilleran

Klondike(140)

Cassiar (140-110)

StuartLake (165)

FIG. 4. A. Present geographic positions of major crustal and tectonic elements of the western North American Cordillera,including the Insular and Intermontane superterranes and the distribution and ages of gold districts. Present-day latitudesare indicated. Terranes are modified from Cowan et al. (1997) and Ward et al. (1997). B. Paleogeographic reconstruction forLate Cretaceous (75–85 Ma). The paleolatitudes for the North American Cordillera at this time are also shown from Wardet al. (1997).

spanning more than 30° latitude, lead to the followinginterpretations:

1. Elemental nitrogen contents and δ15N values of hy-drothermal micas are between 130 and 3,500 ppm and 1.7and 5.5 per mil. This rules out a mantle (low N contents of1–2 ppm and δ15N = –5‰) or granitic fluid sources (N con-tents of 21–27 ppm and δ15N = 6–10‰) but is consistent withfluids derived from metamorphic dehydration reactions ofthe Phanerozoic subduction-accretion complexes, with δ15Nvalues of 1 to 6 per mil.

2. Vein quartz δ18O values are between 14.6 and 22.2 permil but for individual vein systems are strikingly uniform,varying less than ±1 per mil from average values. This impliesboth uniform δ18OH2O and uniform temperatures of precipi-tation for the ore deposits.

3. The δ18O values of gold-bearing vein-forming fluid arecalculated between 8 and 16 per mil (assuming 300°C) andδD values from –10 to –65 per mil, consistent with a deepcrustal source for the ore-forming fluids, most likely of meta-morphic origin.

4. The δD values of ore fluids do not show any latitudinalcontrol, which strongly discounts the meteoric water modelfor these gold deposits. The low δD range of –120 to –130 permil for the Sheba vein in the Klondike district reflects sec-ondary postcrystallization reequilibration between the micasand meteoric waters.

Collectively, the nitrogen, hydrogen, and oxygen stable iso-tope data provide a basis for constraining potential sourcereservoirs for the vein-forming fluids in the western NorthAmerican Cordillera. These are considered to be consistentwith a metamorphic origin, involving derivation of the vein-forming fluids from midcrustal levels by metamorphic dehy-dration reactions at the greenschist to amphibolite transition(Kerrich and Fryer, 1979; Powell et al., 1991). A dilute, aque-ous-carbonic, and N-bearing composition (C-O-H-N) for thevein-forming fluids is similar to that proposed for metamor-phic fluids (Casquet, 1986; Bottrell et al., 1988; Ortega et al.,1991).

AcknowledgmentsWe are grateful to Myles Stocki for assistance with the ni-

trogen analyses, T. Prokopiuk for assistance with oxygen iso-tope analysis in the Department of Geological Sciences, Uni-versity of Saskatchewan, and C. H. Ash and A. Panteleyev forproviding some of the Canadian Cordillera samples. Y. Jia ac-knowledges receipt of a University of Saskatchewan graduatescholarship, a Hugh E. McKinstry grant, the student researchgrant from the Society of Economic Geologists Foundation,and a National Science and Engineering Research Council(NSERC) postdoctoral fellowship. R. Kerrich acknowledgesan NSERC research grant, an NSERC MFA grant, and theGeorge McLeod endowment to the Department of Geologi-cal Sciences, University of Saskatchewan. We thank M. Han-nington, the journal editor, and two journal reviewers, J. Rid-ley and B. Taylor, for their insightful critique of themanuscript and suggestions for improvement.

November 29, 2001; October 16, 2002

REFERENCESAder, M., Boudou, J., Javoy, M., Goffe, B., and Daniels, E., 1998, Isotope

study on organic nitrogen of Westphalian anthracites from the westernMiddle field of Pennsylvania (U.S.A) and from the Bramsche Massif (Ger-many): Organic Geochemistry, v. 29, p. 315–323.

Anderson, P.G., and Hodgson, C.J., 1989, The structure and geological de-velopment of the Erickson gold mine, Cassiar district, British Columbia,with implications for the origin of Mother-Lode type gold deposits: Cana-dian Journal of Earth Sciences, v. 26, p. 2645–2660.

Ash, C.H., 2001, Ophiolite related gold quartz veins in the North AmericanCordillera: B.C. Ministry of Energy and Mines, Energy and Minerals Divi-sion, Geological Survey Branch Bulletin 108, 139 p.

Ash, C.H., Reynolds, P.R., and Macdonald, R.W.J., 1996, Mesothermal gold-quartz vein deposits in British Columbia oceanic terranes. New mineral de-posit models of the Cordillera: B.C. Geological Survey, 1996 CordilleranRoundup Short Course, Unpublished, p. O1–O32.

Bebout, G.E., 1997, Nitrogen isotope tracers of high-temperature fluid-rockinteractions: Case study of the Catalina Schist, California: Earth and Plan-etary Science Letters, v. 151, p. 77–90.

Bebout, G.E., and Fogel, M.L., 1992, Nitrogen-isotope compositions ofmetasedimentary rocks in the Catalina Schist, California: Implications formetamorphic devolatilization history: Geochimica et Cosmochimica Acta,v. 56, p. 2839–2849.

Bigeleisen, J., Pearlman, M.L., and Prosser, H.C., 1952, Conversion ofhydrogenic materials to hydrogen for isotope analysis: Analytical Chem-istry, v. 24, p. 1356–1357.

Böhlke, J.K., 1999, Mother Lode gold: Geological Society of America SpecialPaper 338, p. 55–67.

Böhlke, J.K., and Kistler, R.W., 1986, Rb-Sr, K-Ar, and stable isotope evi-dence for the ages and sources of fluid components of gold-bearing quartzveins in the northern Sierra Nevada foothills metamorphic belt, California:ECONOMIC GEOLOGY, v. 81, p. 296–322.

Bos, A., Duit, W., Eerden, M.J., and Jansen, J.B.H., 1988, Nitrogen storagein biotite: An experimental study of the ammonium and potassium parti-tioning between 1M-phlogopite and vapor at 2 kb: Geochimica et Cos-mochimica Acta, v. 52, p. 1275–1283.

Bottrell, S.H., and Miller, M.F., 1990, The geochemical behaviour of nitro-gen compounds during the formation of black shale hosted quartz-veingold deposits, North Wales: Applied Geochemistry, v. 5, p. 289–296.

Bottrell, S.H., Carr, L.P., and Dubessy, J., 1988, A nitrogen-rich metamor-phic fluid and coexisting minerals in slates from North Wales: Mineralogi-cal Magazine, v. 52, p. 451–457.

Boyd, S.R., and Pillinger, C.T., 1994, A preliminary study of 15N/14N in octa-hedral growth from diamonds: Chemical Geology, v. 116, p. 43–59.

Boyd, S.R., Mattey, D.P., Pillinger, C.T., Milledge, H.J., Mendelssohn, M.,and Seal, M., 1987, Multiple growth events during diamond genesis: An in-tegrated study of carbon and nitrogen isotopes and nitrogen aggregationstate in coated stone: Earth and Planetary Science Letters, v. 86, p. 341–353.

Boyd, S.R., Pillinger, C.T., Milledge, H.J., Mendelssohn, M., and Seal, M.,1992, C and N isotopic composition and the infrared absorption spectra ofcoated diamonds: Evidence for the regional uniformity of CO2-H2O richfluids in lithospheric mantle: Earth and Planetary Science Letters, v. 109,p. 633–644.

Boyd, S.R., Hall, A., and Pillinger, C.T., 1993, The measurement of δ15N incrustal rocks by static vacuum mass spectrometry: Application to the originof the ammonium in the Cambrian batholith, southwest England:Geochimica et Cosmochimica Acta, v. 57, p. 1339–1347.

Burrows, D.R., and Spooner, E.T.C., 1987, Generation of a magmatic H2O-CO2 fluid enriched in Au, Mo, and W within an Archean sodic granodior-ite stock, Mink Lake, northwestern Ontario: ECONOMIC GEOLOGY, v. 82,p. 1931–1957.

Burrows, D.R., Wood, P.C., and Spooner, E.T.C., 1986, Carbon isotope evi-dence for a magmatic origin for Archean gold-quartz vein ore deposits: Na-ture, v. 321, p. 851–854.

Cartigny, P., Boyd, S.R., Harris, W.J., and Javoy, M., 1997, Nitrogen isotopesin peridotitic diamonds from Fuxian, China: The mantle signature: TerraNova, v. 9, p. 175–179.

Cartigny, P., Harris, J.W., and Javoy, M., 1998, Eclogitic diamond forma-tion at Jwaneng: No room for a recycled component: Science, v. 280,p. 1421–1424.

Casquet, C., 1986, C-O-H-N fluids in quartz segregation from a major duc-tile shear zone: The Berzosa fault, Spanish Central system: Journal ofMetamorphic Geology, v. 4, p. 117–130.

δ15N, δD, AND δ18O OF CORDILLERAN GOLD-QUARTZ VEINS 121

0361-0128/98/000/000-00 $6.00 121

Church, B.N., 1997, Age of mineralization, City of Paris, Greenwood area(82E/2E): B.C. Ministry of Energy, Mines and Petroleum Resources, Geo-logical Fieldwork 1996, Paper 1997-1, p. 211–213.

Clayton, R.N., 1981, Isotopic variations in primitive meteorites: Philosophi-cal Transactions of the Royal Society of London, v. 303, p. 339–349.

Clayton, R.N., and Mayeda, T.K., 1963, The use of bromine pentafluoride inthe extraction of oxygen from oxides and silicates for isotopic analysis:Geochimica et Cosmochimica Acta, v. 27, p. 43–52.

Colvine, A.C., Andrews, A.J., Cherry, M.E., Durocher, M.E., Fyon, A.J., Lav-igne, M.J., Macdonald, A.J., Marmont, S., Poulsen, K.H., Springer, J.S., andTroop, D.G., 1984, An integrated model for the origin of Archean lode golddeposits: Ontario Geological Survey Open File Report 5524, 98 p.

Coney, J.P., 1989, Structural aspects of suspect terranes and accretionarytectonics in western North America: Journal of Structural Geology, v. 11,p. 107–125.

Cowan, D.S., Brandon, M.T., and Garver, J.I., 1997, Geologic tests of hypothe-ses for large coastwise displacements—a critique illustrated by the BajaBritish Columbia controversy: American Journal of Science, v. 297, p. 117–178.

Crittenden, M.D., Jr., 1981, Environmental aspects of geothermal develop-ment, in Rybach, L., and Muffev, L.J.P., eds., Geothermal systems: Princi-ples and case histories: New York, John Wiley and Sons, p. 199–217.

Curti, E., 1987, Lead and oxygen isotope evidence for the origin of theMonte Rosa gold lode deposits (Western Alps, Italy): A comparison withArchean lode deposits: ECONOMIC GEOLOGY, v. 82, p. 2115– 2140.

Darimont, A., Burke, E., and Turet, J., 1988, Nitrogen-rich metamorphic flu-ids in Devonian metasediments from Bastogene: Belgium Bulletin of Min-eralogy, v. 111, p. 321–330.

de Ronde, C.E.J., Spooner, E.T.C., de Wit, M.J., and Bray, C.J., 1992, Shearzone-related Au quartz vein deposits in the Barberton greenstone belt,South Africa: Field and petrographic characteristics, fluid properties, andlight stable isotope geochemistry: ECONOMIC GEOLOGY, v. 88, p. 366–402.

Driver, L.A., Creaser, R.A, Chacko, T., and Erdmer, P., 2000, Petrogenesis ofthe Cretaceous Cassiar batholith, Yukon-British Columbia, Canada: Impli-cations for magmatism in the North American Cordilleran Interior: Geo-logical Society of America Bulletin, v. 112, p. 1119–1133.

Elder, D., and Cashman, S.M., 1992, Tectonic control and fluid evolution inthe Quartz Hill, California, lode gold deposits: ECONOMIC GEOLOGY, v. 87,p. 1795–1812.

Fyon, J.A., Schwarcz, H.P., and Crocket, H.J., 1984, Carbonatization andgold mineralization in the Timmins area Abitibi greenstone belt: Geneticlinks with Archean mantle-CO2-degassing and lower crust granulitizaon[abs.]: Geological Association of Canada Program with Abstracts, v. 9, p. 65.

Goldfarb, R.J., Leach, D.L., Rose, S.C., and Landis, G.P., 1989, Fluid inclu-sion geochemistry of gold-bearing quartz veins of the Juneau gold belt,southeastern Alaska: Implications for ore genesis: ECONOMIC GEOLOGYMONOGRAPH 6, p. 363–375.

Goldfarb, R.J., Snee, L.W., Miller, L.D., and Newberry, R.J., 1991a, Rapiddewatering of the crust deduced from ages of mesothermal gold deposits:Nature, v. 354, p. 296–298.

Goldfarb, R.J., Newberry, R.J., Pickthorn, W.J., and Gent, C.A., 1991b, Oxy-gen, hydrogen, and sulfur isotope studies in the Juneau gold belt, south-eastern Alaska: Constraints on the origin of hydrothermal fluids: ECONOMICGEOLOGY, v. 86, p. 66–80.

Goldfarb, R.J., Snee, L.W., and Pickthorn, W.J., 1993, Orogenesis, high-Tthermal events, and gold vein formation within metamorphic rocks of theAlaskan Cordillera: Mineralogical Magazine, v. 57, p. 375–394.

Goldfarb, R.J., Miller, L.D., Leach, D.L., and Snee, L.W., 1997, Gold de-posits in metamorphic rocks of Alaska: ECONOMIC GEOLOGY MONOGRAPH9, p. 151–190.

Goldfarb, R.J., Groves, D.I., and Gardoll, S., 2001, Orogenic gold and geo-logic time: A global synthesis: Ore Geology Reviews, v. 18, p. 1–75.

Golding, S.D., McNaughton, N.J., Barley, M.E., Groves, D.I., Ho, S.E.,Rock, N.M.S., and Turner, J.V., 1989, Archean carbon and oxygen reser-voirs: Their significance for fluid sources and circulation paths for Archeanmesothermal gold deposits of the Norseman-Wiluna belt, Western Aus-tralia: ECONOMIC GEOLOGY MONOGRAPH 6, p. 376–388.

Groves, D.I., Goldfarb, R.J., Grebre-Mariam, M., and Robert, F., 1998, Oro-genic gold deposits: A proposed classification in the context of their crustaldistribution and relationship to other gold deposit types: Ore Geology Re-views, v. 13, p. 7–27.

Guidotti, C.V., and Sassi, F.P., 1998, Petrogenetic significance of Na-K whitemica mineralogy: Recent advances for metamorphic rocks: European Jour-nal of Mineralogy, v. 10, p. 815–854.

Haendel, D., Mühle, K., Nitzsche, H., Stiehl, G., and Wand, U., 1986, Iso-topic variations of the fixed nitrogen in metamorphic rocks: Geochimica etCosmochimica Acta, v. 50, p. 749–758.

Hall, A., 1999, Ammonium in granites and its petrogenetic significance:Earth-Science Reviews, v. 45, p. 145–165.

Hoering, T.C., 1955, Variations in nitrogen-15 in naturally occurring sub-stances: Science, v. 122, p. 1233–1234.

Homes, S.R., McClelland, J.W., Sigman, D.M., Fry, B., and Peterson, B.J.,1998, Measuring 15N- NH in marine, estuarine, and fresh water: An adap-tation of the ammonia diffusion methods for samples with low ammoniumconcentrations: Marine Chemistry, v. 60, p. 235–243.

Honma, H., and Itihara, Y., 1981, Distribution of ammonium in minerals ofmetamorphic and granite rocks: Geochimica et Cosmochimica Acta, v. 45,p. 983–988.

Irving, E., Thorkelson, D.J., Wheadon, P.M., and Enkin, R.J., 1995, Paleo-magnetism of the Spences Bridge Group and northward displacement ofthe Intermontane belt, British Columbia: A second look: Journal of Geo-physical Research, v. 100, p. 6057–6071.

Irving, E., Wynne, P.J., Thorkelson, D.J., and Schiarizza, P., 1996, Large(1000 to 4000 km) northward movements of tectonic domains in thenorthern Cordillera, 83 to 45 Ma: Journal of Geophysical Research, v. 101,p. 17,901–17,916.

Javoy, M., 1997, The major volatile elements of the Earth: Their origin, be-haviour, and fate: Geophysical Research Letters, v. 24, p. 177–180.

Javoy, M., and Pineau, F., 1991, The volatiles record of a “popping” rockfrom the Mid Atlantic Ridge at 14° N: Chemical and isotopic compositionof gas trapped in the vesicles: Earth and Planetary Science Letters, v. 107,p. 598–611.

Javoy, M., Pineau, F., and Demaiffe, D., 1984, Nitrogen and carbon isotopiccomposition in the diamonds of Mbuji Mayi (Zaire): Earth and PlanetaryScience Letters, v. 68, p. 399–412.

Jia, Y., 2002, Nitrogen isotope characteristics of orogenic lode gold depositsand terrestrial reservoirs: Unpublished Ph.D. thesis, Saskatoon, Universityof Saskatchewan, 225 p.

Jia, Y., and Kerrich, R., 1999, Nitrogen isotope systematics of mesothermallode gold deposits: Metamorphic, granitic, meteoric water, or mantle ori-gin?: Geology, v. 27, p. 1051–1054.

——2000, Giant quartz vein systems in accretionary orogenic belts: The evi-dence for a metamorphic fluid origin from δ15N and δ13C studies: Earthand Planetary Science Letters, v. 184, p. 211–114.

Jia, Y., Li, X., and Kerrich, R., 2000, A fluid inclusion study of Au-bearingquartz vein systems in the Central and North Deborah deposits of theBendigo gold field, central Victoria, Australia: Constraints on the origin ofore-forming fluids: ECONOMIC GEOLOGY, v. 95, 467–496.

——2001, Stable isotope (O, H, S, C, and N) systematics of quartz vein sys-tems in the turbidite-hosted Central and North Deborah gold deposits ofthe Bendigo gold field, central Victoria, Australia: Constraints on the originof ore-forming fluids: ECONOMIC GEOLOGY, v. 96, p. 705–721.

Kao, S.J., and Liu, K.K., 2000, Stable carbon and nitrogen isotope systemat-ics in a human-disturbed watershed (Lanyang-His) in Taiwan and the esti-mation of biogenic particulate organic carbon and nitrogen fluxes: GlobalBiogeochemical Cycles, v. 14, p. 189–198.

Kerrich, R., 1987, The stable isotope geochemistry of Au-Ag vein deposits inmetamorphic rocks: Mineralogical Association of Canada Short CourseHandbook, v. 13, p. 287–336.

——1989, Geodynamic setting and hydraulic regimes: Shear zone hostedmesothermal Au deposits: Geological Association of Canada Short CourseNotes 6, p. 98–128.

Kerrich, R., and Allison, I., 1978, Flow mechanism in rocks: Microscopic andmesocopic structures, and their relation to physical conditions of deforma-tion in the crust: Geoscience Canada, v. 5, p. 110–118.

Kerrich, R., and Fryer, B.J., 1979, Archean precious-metal hydrothermal sys-tems, Dome mine, Abitibi greenstone belt. II. REE and oxygen isotope re-lations: Canadian Journal of Earth Sciences, v. 16, p. 440–458.

Kerrich, R., and Wyman, D., 1990, Geodynamic setting of mesothermal golddeposits: An association with accretionary tectonic regimes: Geology, v. 18,p. 882–885.

Kerrich, R., Goldfarb, R. J., Groves, D. I. Garwin, S., and Jia, Y., 2000, Thecharacteristics, origins, and geodynamic settings of supergiant gold metal-logenic provinces: Science in China, v. 43, p. 1–68.

Kistler, R.W., and Silberman, M.L., 1983, Isotopic studies of mariposite-bearing rocks from the south-central Mother Lode, California: CaliforniaGeology, September 1983, p. 201–203.

122 JIA ET AL.

0361-0128/98/000/000-00 $6.00 122

Landefeld, L.A., 1988, The geology of the Mother Lode gold belt, SierraNevada Foothills metamorphic belt, California [ext. abs.]: BicentennialGold 88, Geological Society of Australia, Oral Programme, Extended Ab-stracts, p. 167–172.

Leitch, C.H.B., Dawson, K.M., and Godwin, C.I., 1989, Early Late Creta-ceous, early Tertiary gold mineralization: A galena lead isotope study of theBridge River mining camp, southwestern British Columbia, Canada: ECO-NOMIC GEOLOGY, v. 84, p. 2226–2236.

Leitch, C.H.B., Godwin, C.I., Brown, T.H., and Taylor, B.E., 1991, Geochem-istry of mineralizing fluids in the Bralorne-Pioneer mesothermal gold veindeposits, British Columbia, Canada: ECONOMIC GEOLOGY, v. 86, p. 318–353.

Lu, J., Seccombe, P.K., Foster, D., and Andrew, A.S., 1996, Timing of min-eralization and source of fluids in a slate-belt auriferous vein system, HillEnd goldfield, NSW, Australia: Evidence from 40Ar/39Ar dating and O-andH-isotopes: Lithos, v. 38, p. 147–165.

Madu, B.E., Nesbitt, B.E., and Muehlenbachs, K., 1990, A mesothermalgold-stibnite-quartz vein occurrence in the Canadian Cordillera: ECO-NOMIC GEOLOGY, v. 85, p. 1260–1268.

Maheux, P.J., 1989, A fluid inclusion and light stable isotope study of anti-mony-associated gold mineralization in the Bridge River district, BritishColumbia, Canada: Unpublished M.Sc. thesis, Edmonton, University of Al-berta, 160 p.

Marty, B., 1995, Nitrogen content of the mantle inferred from N2-Ar corre-lation in oceanic basalts: Nature, v. 377, p. 326–329.

Marty, B., and Humbert, F., 1997, Nitrogen and argon isotopes in oceanicbasalts: Earth and Planetary Science Letters, v. 152, p. 101–112.

Matsuhisa, Y., Goldsmith, J.R., and Clayton, R.N., 1979, Oxygen isotope frac-tionation in the system quartz-albite-anorthite-water: Geochimica et Cos-mochimica Acta, v. 43, p. 1131–1140.

McCuaig T.C., and Kerrich, R., 1998, P-T-t-deformation-fluid characteristicsof lode gold deposits: Evidence from alteration systematics: Ore GeologyReviews, v. 12, p. 381–453.

Monger, J.W.H., 1993, Canadian Cordillera tectonics: From geosynclines tocrustal collage: Canadian Journal of Earth Sciences, v. 30, p. 209–231,

Nadelhoffer, K.J., and Fry, B., 1988, Controls on natural 15N and 13C abun-dances in forest soil organic matter: Soil Science Society of America Jour-nal, v. 52, p. 1633–1640.

Nesbitt, B.E., Murowchick, J.B., and Muehlenbachs, K., 1986, Dual origin oflode gold deposits in the Canadian Cordillera: Geology, v. 14, p. 506–509.

Nesbitt, B.E., Muehlenbachs, K., and Murowchick, J.B., 1989, Genetic im-plications of stable isotope characteristics of mesothermal Au deposits andrelated Sb and Hg deposits in the Canadian Cordillera: ECONOMIC GEOL-OGY, v. 84, p. 1489–1506.

Oberthür, T.U., Mumm, A.S., Vetter, U., Simon, K., and Amanor, J.A., 1996,Gold mineralization in the Ashanti belt of Ghana: Genetic constraints ofthe stable isotope geochemistry: ECONOMIC GEOLOGY, v. 91, p. 289–301.

Ortega, L., Vindel, E., and Beny, C., 1991, C-O-H-N fluid inclusions associ-ated with gold-stibnite mineralization in low-grade metamorphic rocks,Mari Rosa mine, Cacers, Spain: Mineralogical Magazine, v. 55, p. 235–247.

Owens, N.J.P., 1987, Natural variations in 15N in the marine environment:Advances in Marine Biology, v. 24, p. 389–451.

Peters, K.E., Sweeney, R.E., and Kaplan, I.R., 1978, Correlation of carbonand nitrogen stable ratios in sedimentary organic matter: Limnology andOceanography, v. 23. p. 598–604.

Pettke, T., and Diamond, L.W., 1997, Oligocene gold quartz veins at Brus-son, NW Alps: Sr isotopes trace the source of ore-bearing fluid to over a 10-km depth: ECONOMIC GEOLOGY, v. 92, p. 389–406.

Pickthorn, J., Goldfarb, R.J., and Leach, D.L., 1987, Dual origins of lode golddeposits in the Canadian Cordillera: Comment: Geology, v. 15, p. 471–472.

Powell, R., Will, T.M., and Phillips, G.N., 1991, Metamorphism in Archeangreenstone belts: Calculated fluid compositions and implications for goldmineralization: Journal of Metamorphic Geology, v. 9, p. 141–150.

Ridley, J.R., and Diamond, L.W., 2000, Fluid chemistry of orogenic lode golddeposits and implications for genetic models: Reviews in Economic Geol-ogy, v. 13, p. 141–220.

Rushton, R.W., Nesbitt, B.E., Muehlenbachs, K., and Muehlenbachs, J.K.,1993, A fluid inclusion and stable isotope study of Au quartz veins in theKlondike district, Yukon Territory, Canada: A section through a mesother-mal vein system: ECONOMIC GEOLOGY, v. 88, p. 647–678.

Sachs, J.P., and Repeta, D.J., 1999, Oligotrophy and nitrogen fixation duringeastern Mediterranean sapropel event: Science, v. 286, p. 2485–2488.

Sibson, R.H., Robert, F., and Poulsen, H., 1988, High angle faults, fluid pres-sure cycling and mesothermal gold-quartz deposits: Geology, v. 16, p.551–555.

Sketchley, D.A., Sinclair, A.J., and Godwin, C.I., 1986, Early Cretaceousgold-silver mineralization in the Sylvester allochthon, near Cassiar, northcentral British Columbia: Canadian Journal of Earth Sciences, v. 23,p. 1455–1458.

Suzuoki, T., and Eostein, S., 1976, Hydrogen isotope fractionation betweenOH-bearing minerals and water: Geochimica et Cosmochimica Acta, v. 40,p. 1229–1240.

Taylor, B.E., 1986, Origins and isotopic characteristics of Mother Lode hy-drothermal fluids and gold deposits with comparison to Archean analogues,in Chapter, A.M., ed., Gold ’86 Poster Volume: Geological AssociationCanada, p. 148–150.

——1987, Stable isotope geochemistry of ore-forming fluid: MineralogicalAssociation of Canada Short Course, v. 13, p. 337–445.

Taylor, B.E., Robert, F., Ball, M., and Leitch, C.H.B., 1991, Mesozoic“Mother Lode type” gold deposits in North America—primary vs. sec-ondary (meteoric) fluids [abs.]: Geological Society of America Abstractswith Program, v. 23, p. A174.

Taylor, H.P., 1997, Oxygen and hydrogen isotope relationships in hydrother-mal mineral deposits, in Barnes, H.L., ed., Geochemistry of hydrothermalore deposits: New York, John Wiley, p. 229–288.

Ward, P.D., Hurtado, J.M., Kirschvink, J.L., and Verosub, K.L., 1997, Mea-surements of the Cretaceous paleolatitude of Vancouver Island: Consistentwith the Baja-British Columbia hypothesis: Science, v. 277, p. 1642–1645.

Weir, R.H., Jr., and Kerrick, D.M., 1987, Mineralogic, fluid inclusion, andstable isotope studies of several gold mines in the Mother Lode, Tuolumneand Mariposa counties, California: ECONOMIC GEOLOGY, 82, p. 328–344.

Wheeler, J.O., and McFeely, P., 1991, Tectonic assemblage map of the Cana-dian Cordillera and adjacent parts of the United States of America: Geo-logical Survey of Canada Map 1712A, scale 1:2,000,000.

Williams, L.B., Ferrel, R.E., Hutcheon, I., Bakel, A.J., Walsh, M.M., andKrouse, H.R., 1995, Nitrogen isotope geochemistry of organic matter andminerals during diagenesis and hydrocarbon migration: Geochimica etCosmochimica Acta, v. 54, p. 765–799.

Wlotzka, F., 1972, Nitrogen, in Wedepohl, K.H., ed., Handbook of geo-chemistry II: New York, Springer-Verlag, p. 7B-1–7O-3.

Wynne, P.J., Irving, E., Maxson, J.A., and Kleinspehn, 1995, Paleomagnetismof the Upper Cretaceous strata of Mount Tatlow: Evidence for 3000 km ofdisplacement of the eastern Coast Belt, British Columbia: Journal of Geo-physical Research, v. 100, p. 6073–6091.

Zhang, X., Nesbitt, B.E., and Muehlenbachs, K., 1989, Gold mineralizationin the Okanagan Valley, southern British Columbia: Fluid inclusion and sta-ble isotope studies: ECONOMIC GEOLOGY, v. 84, p. 410–424.

δ15N, δD, AND δ18O OF CORDILLERAN GOLD-QUARTZ VEINS 123

0361-0128/98/000/000-00 $6.00 123