Targeted Geoscience InitiativeInitiative géoscientifique cibléeTG

emsOre Sys

The Paleozoic carbonate rocks of the southeastern Canadian Cordillera contain a variety of deposit types, including Mississippi Valley-type, magnesite, and REE-F-Ba. These deposits are hosted in weakly deformed, and metamorphosed Paleozoic platform carbonate rocks of the Rocky Mountains. They are found at different stratigraphic levels, however, most of them are hosted in dolostones of the middle Cambrian Cathedral Formation, upper Cambrian Jubilee Formation and Upper Devonian Palliser Formation.

Abstract

The deposits occur along major structurally controlled facies transitions between the shallow-water carbonate platforms and deeper water basin rocks of the Paleozoic continental margin. The location and geometry of these deposits reflect the juxtaposition of structures (e.g., deep-seated faults at platform to deep-water basin transition) and rock types (i.e., permeable and reactive stratigraphic units) favorable to mineralization. This confluence of favorable conditions resulted from episodic rifting and mineralization along the Paleozoic margin during the middle to Late Cambrian and Late Devonian to Middle Carboniferous.

This poster reviews geology, petrography, stable (C, O, S) and radiogenic (Pb, Sr) isotopes, and geochronology of selected carbonate-hosted deposits. Petrography shows dissolution and replacement of the original carbonate by fine-grained “dolomite” followed by different stages of coarser dolomite replacement and cavity fracture fillings (e.g., saccharoidal, sparry and saddle dolomites) accompanied by sulphide deposition, mainly sphalerite, galena and pyrite. Geochemical signatures for each mineralization type show a pattern of dolomitizing and mineralizing fluids interacting with barren host rocks. A more detailed account of the materials presented here can be found in [6].

GeologyThe carbonate-hosted deposits discussed in this poster are in the southern Rocky Mountain Foreland Belt (RMFB; Figs. 1, 2), which is a thin-skinned thrust-and-fold belt that developed along a basal-detachment fault system initiated by Late Jurassic to Paleogene eastward accretion of allochthonous terranes [7, 8]. The strata within the RMFB consist of late Neoproterozoic to Mid-Jurassic imbricated and folded predominantly sedimentary rocks deposited on or adjacent to the stable craton of the Cordilleran margin of ancestral North America. The strata include:

Ÿ Late Jurassic to early Cenozoic marine to non-marine siliclastic rocks eroded from the uplifting Omineca and Foreland belts.

Several carbonate-hosted deposits occur along the platform to deep-water basin transition. For example, east of the projected western margin of the Kicking Horse Rim and the Cathedral Escarpment, middle to upper Cambrian, Ordovician, and Upper Devonian shallow-water platform carbonate rocks host Mississippi Valley-type (MVT; e.g. Monarch and Kicking Horse, Boivin−Munroe−Alpine, Shag, Hawk Creek, and Oldman), magnesite (e.g. Mount Brussilof), and rare-earth element (REE)–F-Ba (e.g. Rock Canyon Creek) deposits (Figs. 2, 3; Table 1). West of the Kicking Horse Rim and Cathedral Escarpment, deep-water basin rocks of the Chancellor Group include the Burgess Shale Formation, and lesser accumulations of limestone and lenses of MgO- and Ba-rich chloritic rocks.

Ÿ Cambrian to Jurassic platform to deep-water basin transition sequences deposited on and near the ancient continental margin of ancestral North America.The Kicking Horse Rim, which corresponds approximately to the projection of the Cathedral escarpment and other escarpments, is an important Paleozoicfault-controlled, paleogeographic high at the platform to basin facies transition.

Ÿ Neoproterozoic to lower Cambrian siliclastic rocks of the Windermere Supergroup deposited during intracontinental rifting.

JuneauJuneauJuneau

InuvikInuvikInuvik

CalgaryCalgaryCalgary

VictoriaVictoriaVictoria

EdmontonEdmontonEdmonton

VancouverVancouverVancouver

WhitehorseWhitehorseWhitehorse

Yellowknife

Prince RupertPrince RupertPrince Rupert

NAb

YT

YT

NAp

NAp

AA

CA

STSMSM

SMSM

SMSM

AX

NAb

KS

QN

AA

YT

YA

CG

NAp

NAb

AG

WR

CG

AX

NAb

AG

CG

NAc

ST

WR

WR

AX

NAp

QNQNQN

OKOK

QN

NAc

CA

YT

CC

CC

NAb

CA

YT

SMSM

SMSMBRBRCDCDCD

PR

CR

PR

CR

108°W

116°W

116°W

124°W

124°W

132°W

132°W140°W

70°N

66°N

66°N

62°N

62°N

58°N

58°N

56°N

54°N

54°N

50°N

50°N

0 100 200 300

km

Coast

plutonic

complex

Alaska

Ala

ska

YukonNWT

BC

Alb

erta

USA

PacificOcean

Chugach

Cache Creek

Wrangellia

Alexander

Yukon-Tanana

Yakutat

Stikinia

Quesnellia

Coast complex

North America - platform

Methow

Kootenay

Cadwallader

Chilliwack

Crescent

Bridge River

Harrison Lake

Slide Mountain

AX

WR

CG

YA

YT

ST

OkanaganOK

QN

HA

CD

CK

MT

PR

CR

BR

SM

CC

KS

NAb

NAp

North America - craton & cover

NAc

CassiarCA

Outboard

Insular

Intermontane

Angayucham, Tozitna

Arctic AlaskaAA

AG

N Alaska

Ancestral North America

TERRANES

easte

rnlim

it

of

Cordilleran

deformation

Kootenay A

rc

Kootenay A

rc

Kootenay A

rc

Rocky Mtns

Rocky Mtns

Rocky Mtns

Carbonate-hosted sulphide Zn-Pb (±Ba, ±Ag) deposits

Clastic-hosted sulphides (~SEDEX)

Carbonate-hosted magnesite

Deposit types

Figure 1. Terranes of the Canadian Cordillera [1] and location of sediment-hosted deposits in rocks of the Ancestral North America margin.

Fig. 2Fig. 2Fig. 2

Rocky Mountains Carbonate-hosted Deposits

The Paleozoic carbonate rocks of the southeastern Canadian Cordillera contain a variety of deposit types, including MVT, REE-F-Ba, and sparry magnesite. The deposits are at different stratigraphic levels, however, most of them are hosted in dolostones of the middle Cambrian Cathedral, upper Cambrian Jubilee, and Upper Devonian Palliser formations (Fig. 3). Most of them occur along major structurally controlled facies transitions between the shallow-water carbonate platforms and deep-water basin rocks near the shelf-slope break of the Paleozoic continental margin. The location and geometry of these deposits reflect the association of structures (e.g. deep-seated faults at platform to deep-water basin transition) and rock types (i.e. permeable and reactive stratigraphic units) favorable to mineralization.

Mississippi Valley-type (MVT) deposits consist of stratabound lenses, layers, pods, breccias, and veins of sulphides preferentially hosted in dolostone of the middle Cambrian Cathedral and Upper Devonian Palliser formations.

Examples: Monarch and Kicking Horse, Munroe, Shag, and Boivin (Figs. 4, 5, 6, 7, 8).Orebodies have single or multiple lenses in dolomitized and/or siliceous carbonate rocks. They are at facies transitions between shallow-water carbonate platform and deeper basin rocks and major basement-controlled structures. Sulphides: Pyrite, sphalerite, galena, and minor chalcopyrite.Gangue: Dolomite, fluorite, calcite, quartz, and minor barite.

Magnesite deposits are preferentially hosted in middle Cambrian shallow marine carbonate rocks of the Cathedral Formation. Magnesite textures vary widely.

Mineralization: Magnesite.

Minor to trace minerals: mica, Mg-rich chlorite, talc, palygorskite/attapulgite, boulangerite, chalcocite, huntite, brucite, fersmite, Nb-bearing rutile, goyazite, and euclase.

Orebody is steeply dipping and coincides with a crackle breccia in carbonate rocks.Mineralization (Fig. 10): REE-F-Ba in REE-bearing fluorocarbonates [bastnaesite-(Ce), parisite-(Ce), synchysite-(Ce)] and a mixture of REE phosphates including monazite-(Ce).Gangue: Dolomite, pyrite, barite, calcite, quartz, and k-feldspar.

Main gangue minerals: Dolomite, calcite, pyrite, quartz, and clay.

Example: Mount Brussilof; producing mine (Fig. 9).Orebodies are stratbound layers, lenses, pods and irregular masses of white to grey magnesite hosted in fine-grained dolostone.

Rock Canyon Creek REE-F-Ba deposit is hosted by dolostone, dolomitic limestone, and carbonate breccia of the Middle Devonian Cedared and Burnais formations (known to contain silty calcareous gypsum).

Paleozoic carbonate-hosted deposits of the southern Rocky Mountains: a review

1* 2 3 2Paradis, S. , Simandl, G.J. , Drage, N. , D'Souza, R.J. , 4 4

Kontak, D.J. , Waller, Z.1Geological Survey of Canada, Sidney, BC

2British Columbia Geological Survey, Victoria, BC

3Dalhousie University, NS

4Laurentian University, ON

corresponding author: suzanne.paradis@canada.ca*

Recommended citation:Paradis, S., Simandl, G.J., Drage, N., D’Souza, R.J., Kontak, D.J., and Waller, Z., 2020. Paleozoic carbonate-hosted deposits of the southern Rocky Mountains: a review. British Columbia Ministry of Energy, Mines and Petroleum Resources, British Columbia Geological Survey GeoFile 2020-07.

Abstract, location, and stratigraphy Geology Geochemistry and Fluid Inclusion Results Ages

Acknowledgments:This study benefited from the assistance and collaboration of Fiona Katay (British Columbia Ministry of Energy and Mines, Regional Geologist based in Cranbrook), and field assistant Michaella Yakimoski (student at University of Victoria). We thank David Pighin and Chris Graf for their perspectives on the geology of the Rocky Mountains and providing samples. Baymag Inc. kindly provided access to the Mount Brussilof mine. Special thank you extends to Ian Knuckey, mine manager, and Alex Hogg and Brody Myers, mine geologists. Wylee Fitz-Gerald helped with setting up and editing the final version of this document.

References: 1. Colpron, M., and Nelson, J.L., 2011; Yukon Geological Survey, , accessed December 2012; also BC Geological Survey, BC GeoFile 2011-11, . 2. Aitken, J.D., 1971; Bulletin of Canadian Petroleum Geology, v. 19, p. 557– 569. 3. Aitken, J.D., 1989; Bulletin of Canadian Petroleum Geology, v. 37, p. 316–333. 4. Katay, F., 2017; British Columbia Ministry of Energy and Mines, British Columbia Geological Survey, Information Circular 2017-1, p. 73–107. 5. Cui, Y., Miller, D., Nixon, G., and Nelson, J., 2015; British Columbia Ministry of Energy and Mines, British Columbia Geological Survey, Open File 2015-2. 6. Paradis, S., Simandl, G.J., Drage, N., D'Souza, R.J., Kontak, D.J., and Waller, Z., 2020; www.geology.gov.yk.ca/bedrock_terrane.html http://www.empr.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/GeoFiles/Pages/2011-11.aspx

Geological Survey of Canada, Bulletin XXX, p. Y–Z. 7. Price, R.A. 1981; Geological Society of London, Special Publication No. 9, pp. 427–448. 8. McMechan, M.E., 2012; Canadian Journal of Earth Sciences, v. 49, no. 5, p. 693-708. 9. Vandeginste, V., Swennen, R., Gleeson, S.A., Ellam, R.M., Osadetz, K., and Roure, F., 2007; Mineralium Deposita, v. 42, p. 913–935. 10. Yao, Q. and Demicco, R.V., 1997; American Journal of Science, v. 297, p. 892–938. 11. Nesbitt, B.E. and Muehlenbachs, K., 1994; Geology, v. 22, p. 243–246. 12. Veizer, J., Ala, D., Azmy, K., Bruckschen, P., Buhl, D., Bruhn, F., Carden, G.A.F., Diener, A., Ebneth, S., Godderis, Y., Jasper, T., Korte, C., Pawellek, F., Podlaha, O.G., Strauss, H., 1999; Chemical Geology, v. 161, p. 59–88. 13. Choquette, P.W. and James, N.P., 1987; Geoscience Canada, v. 14, p. 3-35. 14. Taylor, H.P.,

Frechen, J., and Degens, E.T., 1967; Geochimica et Cosmochimica Acta, v. 31, p. 407–430. 15. Simandl, G.J., Petrus, J., Leybourne, M., and Paradis, S., 2018; Resources for Future Generations Resources for Future Generations 2018, Vancouver, British Columbia, June 16-21, 2018, Abstracts. 16. Jeary, V.A., 2002; M.Sc. thesis, University of Calgary, Calgary, Alberta, 250 p. 16. Machel, H.G. and Cavell, P.A., 1999; Bulletin of Canadian Petroleum Geology, v. 47, p. 510–533. 17. Machel and Cavell, 1999; Bulletin of Canadian Petroleum Geology, v. 47, p. 510-533. 18. Farquhar J., Wu, N.P., Canfield, D.E., and Oduro, H., 2010; Economic Geology, v. 105, p. 509–533. 19. Kiyosu, Y. and Krouse, H.R., 1990; Geochemical Journal, v. 24, p. 21–27. 20. Wilkinson, J.J., 2014; Geochemistry of Mineral Deposits: Treatise on Geochemistry (second edition), (ed.)

S.D. Scott; Elsevier, v. 13, p. 219–249. 21. Nelson, J.L., Paradis, S., Christensen, J., and Gabites, J., 2002; Economic Geology, v. 97, p. 1013–1036. 22. Kontak, D.J, Paradis, S., Waller, Z., and Fayek, M., 2020; Geological Survey of Canada, Bulletin XXX, p. Y–Z. 23. Horita, J.,2014; Geochimica et Cosmochimica Acta, v. 129, p. 111-124. 24. Leach, D.L., Bradley, D., Lewchuk, M.T., Symons, D.T.A., de Marsily, G., and Brannon, J., 2001; Mineralium Deposita v. 36, p. 711–740. 25. Nelson, J.L., Colpron, M., Piercey, S.J., Dusel-Bacon, C., Murphy, D.C., and Roots, C.F., 2006; Geological Association of Canada, Special Paper 45, p. 323-360. 26. Millonig, L.J., Gerdes, A. and Groat, L.A., 2012; Lithos, v. 152, p. 202–217. 27. Nakai, S.I., Halliday, A N., Kesler, S.E., Jones, H.D., Kyle, J.R., and Lane, T.E., 1993; Geochimica et Cosmochimica Acta, v. 57, p. 417-

427. 28. Symons, D.T.A., Pan, H., Sangster, D.F., and Jowett, E.C., 1993; Canadian Journal of Earth Sciences, v. 30, p. 1028-1036. 29. Smethurst, M.T., Sangster, D.F., Symons, D.T.A., and Lewchuk, M.T., 1999; Bulletin of Canadian Petroleum Geology, v. 47, p. 548-555. 30. Hnatyshin, D. 2018; PhD thesis, University of Alberta, Edmonton, Alberta, 306 p. 31. Hnatyshin, D. van Acken, D., Paradis, S., Creaser, C.R. (in preparation). Submitted to Economic Geology. 32. Paradis, S., Gleeson, S., and Magnall, J., 2014; Prospectors and Developers Association of Canada (PDAC), Zinc session. Abstracts with Programs. 33. Pannalal, S.J., Symons, D.T.A., and Leach, D.L., 2007; Canadian Journal of Earth Sciences, v. 44, p. 1661–1673. 34. Paradis, S., Hnatyshin, D., Simandl, G.J., and Creaser, R.A., 2020; Economic Geology, in press. 35. Symons, D.T.A.,

Lewchuk, M.T., and Sangster, D.F., 1998; Economic Geology, v. 93, p. 68–83.

Deposit Deposit

ClassificationCommodity Formation / Unit

Age of Host

RocksLithology Mineralogy

Mount

BrussilofMagnesite Magnesite Cathedral Fm

Middle

CambrianMagnesite

Magnesite. Main gangue minerals: dolomite, calcite,

pyrite, quartz, and clay.

Minor to trace minerals: mica, Mg-rich chlorite, talc,

palygorskite/attapulgite, boulangerite, chalcocite,

huntite, brucite, fersmite, Nb-bearing rutile, goyazite,

and euclase.

Monarch MVTZn, Pb (±Ag,

±Cd)Cathedral Fm

Middle

Cambrian

Massive to thin-bedded

brecciated dolostone

Galena, sphalerite and pyrite in gangue of dolomite and

calcite. Minor chalcopyrite, barite, quartz and native

silver.

Kicking

HorseMVT

Zn, Pb (±Ag,

±Cd)Cathedral Fm

Middle

Cambrian

Massive to thin-bedded

brecciated dolostone

Galena, sphalerite and pyrite (traces of chalcopyrite) in

gangue of dolomite and calcite.

Shag MVT Zn, Pb (±Ag)

Stephen, Eldon

and Waterfowl

fms

Middle to

Upper

Cambrian

DolostoneSphalerite, galena, minor pyrite in a gangue of dolomite,

quartz, and minor calcite.

Munroe MVT ZnPalliser Fm; lower

(Morro) mb

Upper

Devonian

Dolostone with fenestral

porosity (filled by white

sparry dolomite), zebra-like

texture, lesser breccia

Sphalerite, minor pyrite and galena in a gangue of

dolomite; calcite and dolomite fill vugs.

Alpine MVT ZnPalliser Fm; lower

(Morro) mb

Upper

Devonian Dolostone

Sphalerite, minor pyrite and galena in a gangue of

dolomite; calcite and dolomite fill vugs.

Boivin MVT ZnPalliser Fm; lower

(Morro) mb

Upper

Devonian Dolostone

Sphalerite, minor pyrite and galena in a gangue of

dolomite; calcite and dolomite fill vugs.

Hawk

CreekMVT

Zn, Pb (±Ag,

±Au)McKay Group

Upper

Cambrian-

Ordovician

Argillaceous limestone,

argillite, dolomitic

limestone.

Sphalerite, pyrite, galena (silver reported) in a gangue of

calcite and dolomite.

Rock

Canyon

Creek

REE-F-Ba REE-F-BaCedared and

Burnais fms

Middle

Devonian

Dolostone, dolomitic

limestone, carbonate

breccia and laminated silty,

calcareous gypsum.

Dolomite, fluorite, barite, pyrite, quartz, K-feldspar,

calcite, REE-fluorocarbonates and REE-phosphates.

Oldman MVT Pb, Zn, Ag Upper Palliser FmUpper

Devonian

Dolostone, dolomitic

limestone, limestone.

Galena, pyrite, and sphalerite in a gangue of calcite.

Minor: dolomite, ankerite.

Table 1. Principal characteristics of carbonate-hosted deposits of southeastern British Columbia invesitaged during this study

[16]

[16]

[9]

Middle Cambrian marine carbonates

Upper Devonian marine carbonates

MASIRBAS

0.7300

0.7250

0.7200

0.7150

0.7100

0.7050

0.7000-5-10-15-20

d18

OVPDB

87

86

Sr/

Sr

+

+

Oldman, host dolostone

Shag, sparry and saddle dolomite associated to sulphides

Hawk Creek, sparry and saddle dolomite associated to sulphides

Mount Brussilof; sparry dolomite

Mount Brussilof; magnesite

Late calcite (veins and vugs)

Monarch-Kicking Horse; altered (replacive) dolomite

Monarch-Kicking Horse; sparry dolomite

Munroe-Boivin, sparry and saddle dolomite associated to sulphides

Hawk Creek, dolomitic limestone

RCC REE-F-Ba (ferroan) dolomite

RCC dolomitic limestone (host rock, not mineralized)

RCC altered dolostone (with fluorite)

Cathedral Fm limestone (Jeary, 2002)

Cathedral Fm dolospar (Jeary, 2002)

Cathedral Fm sparry-saddle dolomiteat Monarch and Kicking Horse (Vandeginste et al., 2007)

RCC calcite (±F) breccia-matrix and veins

18 87 86Figure 13. δ O versus Sr/ Sr values for various carbonates VPDB

associated with deposits of the southern Canadian Rocky Mountains. Middle Cambrian and Devonian marine carbonate values are from [12]. Maximum Sr isotope ratio of basin shale

87 86(MASIRBAS) is from [17]. Sr/ Sr values of MVT and magnesite hydrothermal dolomites are similar or higher than their host dolostone. However, Rock Canyon Creek dolomites have lower 87 86Sr/ Sr values than those from MVT and magnesite deposits.

CMCDMC

Yao and Demicco (1997)

Vandeginste et al. (2007)

Nesbitt and Muehlenbachs (1994)

Mete

oric

Increased burial and/or hydrothermal fluids

+

+++

++ ++ -8-14 -12 -6 -4 -2 0-22 -20 -18 -16

(‰)d18

OVPDB

-8

-6

-4

-2

0

2

4

d(‰

)13C

VP

DB

+

Munroe-Boivin, dolostone (least altered)

Munroe-Boivin, saccharoidal dolomite

Munroe-Boivin, sparry and saddle dolomite associated to sulphides

Shag, altered (replacive) dolomite

Shag, dolostone (least altered)

Shag, sparry and saddle dolomite associated to sulphides

Oldman, host dolostone

Mount Brussilof; sparry dolomite

Mount Brussilof, magnesite

Monarch-Kicking Horse, dolostone (least altered)

Monarch-Kicking Horse, altered (replacive) dolomite

Monarch-Kicking Horse, sparry dolomite

Oldman, calcite associated to sulphides

Hawk Creek, dolomitic limestone

Hawk Creek, sparry and saddle dolomite associated to sulphides

Late calcite (veins and vugs)

[9]

[10]

[11]

CMC = Cambrian Marine Carbonate [12]DMC = Devonian Marine Carbonate [12]

13 18Figure 11. δ C versus δ O of host dolostone and VPDB VPDB

hydrothermal dolomites associated with MVT and magnesite deposits. Hydrothermal dolomites associated with

18mineralization have lower δ O values than their VPDB

respective dolostone host rocks. Our data compare well with the hydrothermal dolomites of [9], [10] and [11]. The generalized trends for burial, hydrothermal and meteoric fluids of [13] are illustrated by arrows.

y = 1.3709x + 0.9471R² = 0.8961Robb Lake

MVT

Cluster 1

Cluster 2Cluster 3

B)

Deposits of the southern Rocky Mountains

Upper crust

OrogeneShale curve

“Cordilleran carbonate trend”

Lead MountainPb-Zn deposit

208

206

Pb/

Pb

Pb/ Pb207 206

2.20

2.15

2.10

2.05

2.00

1.85

1.90

1.95

0.90 0.85 0.80 0.75 0.70

Shag

Hawk Creek

Mt Brussilof magnesite

Munroe

Oldman

Monarch/Kicking Horse

DevonianPalliser Fm

Mid-CambCathedral Fm

and equiv.

Upper Camb-OrdMcKay Group

Pb-Zn deposits of the northern Rocky & Mackenzie Mountains and WCSB (including Robb Lake MVT)

207 204 206 204 207 206 208 206Figure 15. A) Pb/ Pb versus Pb/ Pb; and B) Pb/ Pb versus Pb/ Pb of galena, pyrite, and sphalerite from carbonate-hosted deposits of the southern Rocky Mountains compared to the “Cordilleran carbonate trend”, which includes Zn-Pb occurrences and deposits of the northern Rocky Mountains, Mackenzie Mountains, and Western Canada Sedimentary Basin (WCSB). The data form 3 clusters, each defined by specific deposits. Cluster 1, the least radiogenic group, is from the Monarch, Kicking Horse and Munroe deposits. Cluster 2 consists exclusively of samples from Shag deposits. Cluster 3, the most radiogenic group, consists of Hawk Creek, Mount Brussilof, Oldman, and Munroe deposits, which plot within the “Cordilleran-carbonate trend” defined by carbonate-hosted Zn-Pb deposits and occurrences of the northern Rocky Mountains, Mackenzie platform, and WCSB (cf. [21]). The dashed lines in A) and B) represent the trendline for all the data within the “Cordilleran carbonate trend”. They intersect clusters 1 and 2, and a cluster of unradiogenic lead data from the Lead Mountain deposit, a vein- and fracture-controlled carbonate-hosted sulphide-barite deposits in the western Foreland Belt of the Rocky Mountains. This suggests that Pb signature of clusters 1, 2, and 3 represents mixtures of variably radiogenic end members.

Breakup of Rodinia Assembly of Pangea

Dispersionof Pangea

Pangeastable

Pangeaunstable

Breakupof Pangea

LaramideOrogeny

Laramide Orogeny (~90-50 Ma)

Antler Orogeny (~370-340 Ma)

1Arc magmatism (NA margin)

600 500 400 300 200 100

PC C O S D C P Tr J K T age(Ma)

600 500 400 300 200 100

PC C O S D C P Tr J K T age(Ma)

3Pine Point Zn-Pb

6Salmo Zb-Pb7Pend Oreille Zn-Pb

4Robb Lake Zn-Pb

8Monarch-Kicking Horse Zn-Pb

5Prairie Creek Zn-Pb-Ag

Carbonate-hosted deposits

Host rocksOrogeny/magmatic events Paleomagnetic Radiometric

Figure 20. Summary of known radiometric and paleomagnetic ages of Zn-Pb carbonate-hosted 1 2mineralization and their host rocks. Figure modified from [24]. Data from [25]; Radiometric data

3from various sources and compiled by [26]. Abbreviation: NA – North America; Radiometric data 4(Rb-Sr) from [27], paleomagnetic data from [28]; Radiometric data (Rb-Sr) from [21],

5paleomagnetic data from [29]; Radiometric data (Re-Os) from [30] and [31] (work in progress); 6 7Radiometric data (Re-Os) from [30], [31] and [32]; Paleomagnetic data from [33], radiometric

8data from [34]; Paleomagnetic data from [35].

Carbonatites and associated 2alkaline complexes (NA margin)

N

0 100kilometres

Nelson

Fernie

Castlegar

Cranbrook

Invermere

Kimberley

Vernon

Revelstoke

Field

o

49 No

49 No

49 N

an�clinorium

an�clinorium

an�clinorium

PurcellPurcellPurcell

Kootenay

Kootenay

Kootenay

Rocky Mountain

Rocky Mountain

Rocky Mountain

Foreland

Foreland

Foreland

BeltBeltBelt

ArcArcArc

Cathedral Escarpment

Rocky Mountain Trench

Sediment-hosted deposits

Monarch andMonarch andKicking HorseKicking HorseMonarch andKicking Horse

ShagShagShag

Hawk CkHawk CkHawk Ck

MunroeMunroeMunroe

BoivinBoivinBoivinAlpineAlpineAlpine

Rock Canyon CkRock Canyon CkRock Canyon Ck

OldmanOldmanOldman

Mount BrussilofMount BrussilofMount Brussilof

U.S.A.U.S.A.U.S.A.

Paci

fic O

cean

Paci

fic O

cean

Paci

fic O

cean

Atla

ntic

Oce

an

Atla

ntic

Oce

an

Atla

ntic

Oce

an

RoadRail line

Transportation

Geology

Intrusives

Slide MountainQuesnellia

Platformal strataBasinal strata

Neogene to Quaternary volcanics

Supracrustal

Ancestral North America platformal

Post accretionary assemblages

Terranes

Alberta

Vein- and fracture-controlled replacement Pb-Zn (±Ag,±Au)

Magnesite

Stratabound Ba-Pb-Zn vein

Figure 2. Regional geological map of southeastern Canadian Cordillera showing locations of the sediment-hosted deposits. The projection of the Cathedral escarpment (red dashed-line) corresponds approximately to the western margin location of the Kicking Horse Rim, a paleogeographic high that was initiated in the early middle Cambrian and persisted into the Ordovician [2,3]. Both features mark the change from shallow-water carbonate rocks to the east and continental slope lithofacies to the west during the early Paleozoic. Modified from [4]. Terranes from [5].

Alberta Gp

Crowsnest Fm

Blairmore Gp

Elk Fm

Mist Mountain Fm

Morissey Fm

Fernie Fm

Ko

ote

nay

G

p

Spray RiverGp

Whitehorse

Sulfur Mtn

Rockie MtnSupergroup

Ranger Canyon

Ishbel Gp

Spray Lakes Gp

Rundle Gp

Banff Fm

Exshaw FmPalliser Fm

Alexo/Sassenach FmFairholme Gp

MountForster

HarrogateCedared/Burnais

Beaverfoot Fm

Mount Wilson Fm

OwenCk/Skoki/Outram

Bison Ck/Mistaya/Survey Peak

Waterfowl/Arctomys FmSullivan/Lyell/Jubilee Fm

Pika/Eldon/Stephen Fm Cathedral Fm

Mt Whyte Fm

Mie�e/Gog Gp

SoutheastBri�sh ColumbiaQuaternary

Ter�ary

Cretaceous

Jurassic

Permian

Triassic

Carb.Miss

Pensyl

Devonian

Silurian

Ordovician

Cambrian

Neo-Proterozoic

2.6

65.5

145.5

201.6

251

299

359

416

444

488

542

1000

Munroe, Alpine, Boivin

MonarchBaker Ck, Eldon

Shag

Hawk Ck

Rock Canyon Ck

Oldman

Rundle Gp

Banff Fm

Exshaw Fm

Palliser FmAlexo/Sassenach Fm

Fairholme Gp

MountForster

HarrogateCedared/Burnais

Beaverfoot Fm

Mount Wilson Fm

OwenCk/Skoki/Outram

Bison Ck/Mistaya/Survey PeakMcKay Group

Waterfowl/Arctomys FmSullivan/Lyell/Jubilee Fm

Pika/Eldon/Stephen Fm Cathedral

Mt Whyte

Mie�e/Gog Gp

Kicking HorseMt Brussilof

Island arc volcaniclas�cs and epiclas�c rocks, flows, tuffs, trans-tensional volcanics

Fine-grained marine rocks (limestone, dolostone, mudstone, phyllite, schist)

Medium- to coarse-grained clas�c rocks (sandstone, conglomerate, siltstone, quartzite)

Reefal and crystalline carbonates, marbles

Unconformity

Evaporites and shallow marine carbonates

Fine-grained clas�c rocks (siltstone, shale, argillite)

{

Mississippi Valley-type (MVT) Zn-Pb deposit

Carbonate-hosted magnesite deposit

MVT deposit not studied

Unconformity

Carbonate-hosted REE-F-Ba deposit

Figure 3. Generalized stratigraphy of the Purcell anticlinorium and the Rocky Mountain Foreland Belt with locations of studied deposits indicated by stars. Modified from [4].

SparryDol

Do frag

Sph+Py

100 µm

SphSphSph

DolDolDol

BBBAAA

Figure 4. Kicking Horse MVT deposit. A) Aggregates of sphalerite (Sph)+pyrite (Py) in white sparry dolomite (Do) cement. B) Colloform sphalerite exhibiting colour zonation adjacent to white sparry dolomite; PPL = Plane-Polarized Light.

SphSphSph

Dol+QzDol+QzDol+Qz

AAA

QzQz(minor Dol)(minor Dol)

Qz(minor Dol)

BBB

1000 µm

SphSphSph

Qz Qz Qz

Figure 5. Shag MVT deposit. A) Sample of Red Bed showing displays alternating bands of white dolomite and quartz and darker dolostone rich in red sphalerite (Sph). B) The C-4 showing with intense replacement by granular sphalerite in a matrix of quartz and dolomite, with minor pyrite and galena (black); PPL.

BBBSph 1Sph 1Sph 1 Dol 2Dol 2Dol 2

Dol 1Dol 1Dol 1

500 um500 um500 um

Figure 7. Hawk Creek MVT deposit. A) Massive layered/banded sphalerite and less pyrite, galena replacing argillites and argillaceous dolostone of the middle Cambrian McKay Group. B) Sphalerite 1 (Sph 1) surrounded by fine crystalline dolomite (Dol 1) and coarse-grained saddle dolomite (Dol 2); PPL.

AAA

1000 µmHost DoHost DoHost Do

CcCcCc

SphSphSph

1000 µm

SphSphSph

DolDolDol

Figure 8. Oldman MVT deposit. A) Sphalerite (Sph) interstitial to dolomite (Dol); PPL. B) Colloform sphalerite (Sph) fills open spaces. Smaller grains are interstitial to or replace the dolomite (Host Do); PPL.

AAABBB

SphSphSph

Sparry DolSparry DolSparry Dol

Sacch DolSacch DolSacch Dol

Host DoHost DoHost DoSacchSacch

DolDolSacch

Dol

SphSphSph

500 µm

DolDolDol

Figure 6. Munroe MVT deposit. A) Zebra texture created by the alternating bands of dark grey dolostone (Host Do) replaced by saccharoidal dolomite (Sacch Dol) rich in sphalerite (Sph), and white sparry dolomite lenses. B) Nonplanar or planar-e to planar-s dolomite (Dol), coarser-grained saccharoidal dolomite (Sacch Dol) and intergranular sphalerite (Sph); PPL.

AAA BBB

Magnesite

SparrySparryDolDol

SparryDol

FrsFrsFrs

100 µm

BBBAAA

Figure 9. Mount Brussilof magnesite deposit (Baymag mine). A) Coarse-grained grey magnesite ore. B) Fersmite (Frs) crystal in sparry dolomite (Sparry Dol); PPL.

PyritePyritePyrite

PyritePyritePyrite

Ferroan dolomiteFerroan dolomiteFerroan dolomite

Ferroan dolomiteFerroan dolomiteFerroan dolomiteFluoriteFluoriteFluorite

FluoriteFluoriteFluorite

FluoriteFluoriteFluorite

BariteBariteBarite

SynchysiteSynchysiteSynchysiteBastnäsite-MonaziteBastnäsite-MonaziteBastnäsite-Monazite BastnäsiteBastnäsiteBastnäsite

Figure 10. Rock Canyon Creek REE-F-Ba deposit. A) Large euhedral crystals of barite in purple fluorite vein cutting altered dolostone (DDH-09-01 at 38.7 m). B) Backscatter electron image of mineral assemblage from the REE-F-Ba mineralization.

AAA BBB

Upper crustShale curve

Orogene

Mantle

Deposits of the southern Rocky Mountains

y = 0.1149x + 13.521R² = 0.9716

Robb Lake MVT

Lead MountainPb-Zn deposit

Cluster 1

Cluster 2

Cluster 3“Cordilleran carbonate trend”Includes Zn-Pb occurrences of the northern Rocky Mtns, Mackenzie Mnts, and WCSB

(including Robb Lake MVT deposit)

207

204

15.4

15.5

15.6

15.7

15.8

15.9

16.0

16.1

16.2

16.3

16.4

17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0 26.0

206 204Pb/ Pb

Pb/ P

b

Shag

Hawk Creek

Mt Brussilof magnesite

Munroe

Oldman

Monarch/Kicking Horse

DevonianPalliser Fm

Mid-CambCathedral Fm

and equiv.

Upper Camb-OrdMcKay Group

A)

Southern BCcarbonatites

(Simandl, unpublished data)

Primary igneouscarbonatites

Sediment contaminationor high T fractionation

RCC: Carbonates associated to mineralization (this study)

RCC: Host carbonates (this study)

RCC: Altered dolostone (this study)

RCC: Saddle dolomite (this study)

CMCDMC

MVT deposits: Dolomite associatedwith mineralization

(this study)

MVT deposits: Host dolostone(this study)

-8

-6

-4

-2

0

2

4

-22 -20 -18 -16 -14 -12 -10 -8 -6 -4 -2 0

d(‰

)13C

VP

DB

(‰)d18

OVPDB

[14]

[15]

13 18Figure 12. Plot of δ C versus δ O . Values for dolomites VPDB VPDB

associated with MVT, magnesite, and REE-F-Ba deposits are lower than respective host carbonate rocks. Dolomite associated with Rock

13Canyon Creek (RCC) REE-F-Ba mineralization has δ C versus VPDB18δ O values similar to dolomite associated with MVT and VPDB

magnesite deposits; these values plot outside the fields of southern British Columbia carbonatite (yellow) and primary igneous carbonatites (defined by [14]).

Figure 17. Homogenization temperature (Th) versus salinity (wt. % equiv. NaCl). The data indicate broad ranges of temperature (<80–200°C) and salinity (0.9–28 wt.%), even in some cases for single settings (e.g., Monarch 0.9–20.2 wt. %; Mastodon 3.1–23.1 wt. %). Mastodon and O'Donnell deposits are located in the Kootenay Arc of southern BC [22].

00

50 100 150 200 250

5

10

15

20

25

30

Homogenization Temperature(°C)

Salin

ity (

wt%

NaC

l eq

) Robb Lake (RL-2-2)Robb Lake (RL1B-1)ShagMonarchMastodonO’Donnell

-4 0 4 8 12 16 20

-8

-12

-16

-20

200

160

120

80

40

0 4 8 12 16 20 24 28 32 36 40

FCD MCD/CCD/SD Calcite

18δ O (‰)carbonate

oTe

mp

era

ture

(C

)

18Figure 18. Plot of δ O (‰) values for different carbonate types SMOW18versus Temperature. The curved lines are δ O values of H2O

precipitating fluids calculated using the dolomite-H O fractionation 2

equation of [22]. The dashed black line traces the idealized evolutionary trend of a fluid in a MVT setting [23]. Reeves MacDonald deposit is in the Kootenay Arc of southern BC, and Dawson Oil Field and Great Slave Reef are in the Western Canada Sedimentary Basin.

Dawson Oil Field

Great Slave Reef

Reeves MacDonald

Robb Lake

Kicking HorseCaCO3

FeCO3 MgCO3

Carbonate types

40%

50%

60%

FCDMCDCCDSD

Calcite70

90

80

60

50

40

30

20

10

90

n=109

807060504020 3010

90

80

70

60

50

30

40

20

10

Dolomite

Ferroan dolomite

Ca-d

olo

mite

n=76

Figure 16. Ternary plots of CaCO -FeCO -MgCO (in atomic %) for different dolomite 3 3 3

types and calcite from different study areas. Dolomite is generally stoichiometric chemically, but ore-stage types (CCD and SD) are the most Fe-rich (up to 6 mol % FeCO ). Data were collected using SEM-EDS analysis. Abbreviations: FCD = fine-3

grained crystalline dolostone (~host dolostone), MCD = medium-grained crystalline dolomite, CCD = coarse-grained crystalline dolomite, SD = saddle dolomite [22].

Figure 19. Fluid inclusions (FI) hosted in sphalerite. The inclusions are primary (P), pseudosecondary (PS) and secondary (S) and indeterminate (I) types. A) Kicking Horse: zoned, yellow to clear sphalerite with FI of P types. B) Monarch: zoned yellow to clear sphalerite inundated with opaque FI of P types. C) Monarch: clear to red zoned sphalerite inundated with irregular-shaped FI of P, S and I types. D) & E) Shag: zoned red to clear sphalerite with FI of P and S types. Image E shows an enlarged FI (black arrow) with low vapour phase relative to liquid (V:L ratio) and thus a low Th value (<80°). F) & G) Shag: clear to yellow, zoned sphalerite hosting small to large, equant FI of I type defining a 3D array. Most of the FI are opaque, but inset with outlined black box is a small vapour phase [22].

AAA BBB CCC DDD EEE FFF GGG

Fluid Inclusions

3020 100-10-20 40

500

400

300

600

34δ S (‰)VCDT

Ag

e (

Ma

)

Galena

PyriteBarite

Sphalerite

Hawk Creek

Munroe

Rock Canyon Ck

Boivin Oldman

Shag

Kicking Horse

Monarch

Mt Brussilof

Marine sulphate composition [18]

Mean sedimentary pyrite composition produced by BSR

Likely range of sulphide compositions produced

by TSR

+ + +++

++++++

++

+

+

+

+

Figure 14. Sulphur isotope values of carbonate-hosted deposits in relation to age of host rocks. Sulphur in most MVT deposits is consistent with an origin from seawater sulphate, reduced by thermogenic sulphate reduction (TSR) and locally bacterogenic sulphate reduction (BSR) occurred. Modified from [20].

[19]

[18]

Natural ResourcesCanadaResources NaturellesCanada

Conclusions§ Deposits covered by this study are hosted by shallow-water platform carbonate rocks of

Ancestral North America (Fig. 1). They are located east of the Rocky Mountain trench along theprojection of the Cathedral escarpment (Fig. 2). This escarpment coincides with structurallycontrolled facies transitions between platform carbonate rocks and deep-water basin rocks.

§ Dolomite composition is typically stoichiometric; however, ore-stage varieties (“replacive”,coarse-grained sparry and saddle dolomites) are enriched in Fe (up to 6 mol % FeCO ; Fig.3

16).

18 13§ The δ O and δ C values of hydrothermal dolomites at Rock Canyon Creek REE-F-BaVPDB VPDB

deposit are intermediate between values of carbonatites and host carbonate rocks (Fig. 12).87 86Their Sr/ Sr values (0.70588 to 0.70873; Fig. 13) are similar or lower than their host

carbonate rocks (0.70866 to 0.70903). This suggests that REE-F-Ba mineralization at RockCanyon Creek may have formed from distal carbonatite-related fluids interacting withcarbonate host rocks and mixing with ambient fluids.

§ Deposits are associated with syn- to post-depositional dolomitization represented by“replacive”, sparry and saddle dolomites (Fig. 4 to 10). These dolomites resulted fromhydrothermal fluid migration along fault systems and strata with enhanced porosity andpermeability.

§ Mineralization occurred intermittently (in more than one stage) during the Paleozoic, i.e.middle to late Cambrian and Late Devonian to middle Carboniferous (Fig. 20).

§ The homogenization temperatures, measured from fluid inclusions trapped in sphalerite fromthe Rocky Mountains MVT deposits (~ 160−240ºC, pressure corrected to 1 kbar; Figs. 17, 18,19), support a hydrothermal origin.

§ Sulphur isotope values of Sulphide minerals show large variations within a deposit (e.g. +20.534to +32.9‰ at Mount Brussilof) and among different deposits (e.g. across all deposits, δ SVCDT

values range from -2.8% to +36.6%, n=53, with most values from +9.9 to +36.6‰, n=51).Reduced sulphur formation predominantly occurred through TSR of coeval seawater sulphatefor most deposits (e.g. Kicking Horse, Monarch, and Hawk Creek). However, BSR alsooccurred locally (e.g. at Boivin; Fig.14).

§ Lead isotopes suggest a mixing trend involving highly radiogenic and non-radiogenic endmembers (Fig. 15).

18 13§ The δ O (-20.0 to -9.8‰) and δ C (-8.6 to +1.1‰) values for “replacive”, sparry, andVPDB VPDB

saddle dolomites associated with MVT, magnesite, and REE-F-Ba deposits are lower than18 13their respective host carbonate rocks (δ O = -15.2 to -7.1‰; δ C = -2.9 to +1.2‰), andVPDB VPDB

they compare well with other hydrothermal dolomites in the RMFB (Fig. 11, 12).

§ Fluids responsible for “replacive”, sparry and saddle dolomites associated with MVT andmagnesite deposits were of hydrothermal origin, modified by interaction with siliclastic andcarbonate rocks, and were expelled from deep burial settings by tectonic stresses, as

18exemplified by high temperatures (~ 160−240ºC), low δ O values (-20.0 to -11.5‰), andVPDB87 86high Sr/ Sr ratios (0.70879 to 0.71484).