52.68° 52.68° 52.95° 52.95° 52.45° 52.45° 120.58° 120.58° 121.23° 121.23° 121° 121° N Quesnel Lake Quesnel Lake (North Arm) (North Arm) Mitchell Lake Mitchell Lake Ghost Ghost Lake Lake Cariboo river Cariboo river Cameron creek Cameron creek 3100 road 3100 road 8400 road 8400 road Little River Little River Lostway Lostway Creek Creek thrust thrust 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 10 10 Pleasant Pleasant Valley Valley thrust thrust 0 10 km Map area of Fig. 3 Map area of Fig. 3 Thrust fault Fault Mineral occurrence Geological contact 2 2 Kootenay terrane Cariboo terrane Snowshoe Group Quaternary: thick alluvium Bralco succession Undivided Snowshoe Group Late Proterozoic and Paleozoic Downey succession Mount Baker volcanic rocks Jurassic and Cretaceous granodiorite and quartz monzonite Mississippian granitic intrusive rocks Early Permian diorite Quaternary basalts Ordovician to Mississippian Late Proterozoic to Cambrian Kaza Group Isaac, Cunningham, Yankee Belle formations Yanks Peak, Midas, Mural, Dome Creek formations Cariboo Group Black Stuart Group To Barkerville Maeford Lake Grizzly Lake Grizzly Lake DeBasher Lake DeBasher Lake Peach Lake Peach Lake To Likely Summit Lake Summit Lake Maker Lake Peanut Lake Peanut Lake N DeBasher DeBasher Canopener Canopener Flipper Creek Flipper Creek Main Main Gunn Gunn Dolomite Flats Dolomite Flats Que Que Granodiorite to quartz monzonite Phyllite (silver-green) Siltstone (greenish) Carbonate rocks Pelitic rocks Schistose muscovite limestone Well-banded grey and white limestone Grey massive limestone Limy dolostone-dolomitic limestone Cream dolostone (fine-grained, massive) Road Bedding Schistosity Pb-Zn showing Geological contact Fault 0 500 1500 1000 metres ? ? ? ? A A B B C C D D A A B B C C D D Nonsulphides Nonsulphides Nonsulphides Nonsulphides Oxidized sulphides Oxidized sulphides Oxidized sulphides Oxidized sulphides A A B B C C D D Sphalerite Sphalerite Galena Galena Galena Galena Galena Galena Quartz Quartz Quartz Quartz Nonsulphides Nonsulphides Nonsulphides Nonsulphides Sphalerite Sphalerite A A C C D D E E F F B B Oxidized Sphalerite Sphalerite Barite Barite Sphalerite Sphalerite A A B B Figure 4. Dolomite Flats prospect. A) Typical outcrop exposure in the Dolomite Flats area. B) Orange-brown patches corresponding to oxidized sulphides disseminated in the dolostone. C) Fracture-filling oxidized sulphides (nonsulphide) forming boxwork texture in the dolostone. D) Close-up of fine grains and aggregates of nonsulphides and oxidized sulphides in the dolostone. Smallest subdivision on the scale corresponds to 1 mm. Figure 5. Main prospect. A) Main trench. B) Quartz-sphalerite-galena-nonsulphide (after sphalerite) vein. C) Quartz-galena vein. D) Pod of galena, nonsulphides (cerussite) and sphalerite that forms part of a vein-breccia system. Figure 6. Gunn showing. A) Fine-grained recrystallized white dolostone. B) Disseminated oxidized (orange) and fresh (yellowish) sphalerite in the fine-grained dolostone. C) Aggregates of fresh yellow sphalerite in the fine-grained white dolostone. D) Oxidized reddish brown sulphides (presumably sphalerite) in the white dolostone. E) Barite-galena-sphalerite vein crosscutting the dolostone (only barite is clearly visible in the photograph). F) Main Gunn excavation partially covered by snow. Figure 7. Gunn showing. A) White to grey, translucent to transparent radiating crystals, 2-3 mm in length (probably cerussite). B) Stubby white transparent crystals (probably anglesite) lining cavities. Scale is in millimetres. Figure 8. Que showing. A) Shallow exploration trenches (arrow), stripped outcrops and subcrops. B) Close-up view of nonsulphide minerals (orange and white). C) Large angular nonsulphide-bearing blocks. D) Radiating tabular translucent crystals of cerussite in cavity. Scale is in millimetres. Figure 1. Location of the Cariboo terrane and the study area (Cariboo Zinc property) with respect to other significant carbonate-hosted sulphide and nonsulphide occurrences in the northern cordillera (modified from Nelson et al., 2002, 2006). Abbreviations: St - Stikine terrane, CC - Cache Creek, Q - Quesnel terrane, SMRT - southern Rocky Mountain trench. Figure 2. Regional geological setting of the study area (after Campbell, 1978; Struik, 1983a, b, 1988; Ferri and O’Brien, 2003), east-central BC. The dotted rectangle is the area covered by Figure 3. Mineral occurrences, according to BC MINFILE (BCGS, 2009): 1 - Sil (corresponds to the Gunn and Que showings in this study), 2 - Grizzly Lake (corresponds to the Flipper Creek, Dolomite Flats, and Main showings in this study), 3 - Lam (corresponds to the DeBasher showing in this study), 4 - Comin Throu Bear, 5 - Maybe, 6 - Mt Kimball, 7 - Maeford Lake, 8 - Ace, 9 - Mae, 10 - Cariboo Scheelite. Occurrences 1, 2, and 3 form the Cariboo Zinc property. Figure 3. Geology of the Cariboo Zinc property area showing the location of the Canopener, DeBasher, Flipper Creek, Dolomite Flats, Main, Gunn, and Que showings (from Lormand and Alford, 1990). Figure 9. Galena nodules discovered in a north- flowing stream less than 50 m upstream from high-grade nonsulphide boulders shown on Figure 8c (Que showing). Summary Carbonate-hosted nonsulphide Pb-Zn deposits of south-eastern BC (Figure 1) were covered by Simandl and Paradis (2009). This present study demonstrates that nonsulphide Pb-Zn deposits can be found much further north than previously anticipated. Results of ongoing mineralogical, geochemical, and isotopic studies will contribute to a better understanding of these deposits. Estimates of physical properties of nonsulphide-bearing rocks may help exploration programs and drill target selection. Characteristics of Cariboo zinc occurrences Host rocks: Fine-grained cream-coloured dolostone and limy dolostone. Texture/structure: Sulphide and nonsulphide Pb-Zn minerals occur as disseminations, replacement zones, and fracture-, vein- and breccia-fillings. Ore mineralogy: Sulphides = galena, sphalerite and trace amounts of pyrite. Nonsulphides = smithsonite, hemimorphite, cerussite, hydrozincite and anglesite (?). Gangue minerals = dolomite, calcite, quartz, and locally barite. Alteration: Dolomitization and silicification pre-dating, or contemporaneous with sulphides and pre-dating Pb-Zn nonsulphides. Ore controls: • Pb-Zn occurs along a SE-trending belt about 8 km long. It is confined to a stratabound zone restricted to dolomitic carbonates, adjacent to phyllite. • Historical reports suggest that Pb-Zn mineralization is largely fault-controlled; however we were unable to confirm this control during our short visit. • Nonsulphides are derived from sulphide mineralization in the near surface environment. At depth, nonsulphide mineralization may be limited by the level of the water table. Karst may be present in the area; however, its importance as an ore control remains to be confirmed. Suggested reference: Paradis, S., Simandl, G.J., Bradford, J., Leslie, C. and Brett, C. (2010): Carbonate-hosted sulphide and nonsulphide Pb-Zn Mineralization, Cariboo terrane, British Columbia; British Columbia Ministry of Energy, Mines and Petroleum Resources; Geofile 2010-4, poster. Carbonate-hosted sulphide and nonsulphide Pb-Zn mineralization, Cariboo terrane, BC, Canada 1,3 2,3 4 5 6 Suzanne Paradis , George J. Simandl , John Bradford , Christopher Leslie , Curtis Brett 2. British Columbia Ministry of Energy, Mines and Petroleum Resources, Victoria, BC 3. University of Victoria, School of Earth and Ocean Sciences, Victoria, BC 1. Geological Survey of Canada, Sidney, BC References: For complete list of references, please consult: Paradis, S., Simandl, G.J., Bradford, J., Leslie, C. and Brett, C. (2010): Carbonate-hosted lead-zinc mineralization on the Cariboo zinc property, Quesnel Lake area, east-central British Columbia (NTS 093A/14E, 15W); in: Geological Fieldwork 2009, BC Ministry of Energy and Mines and Petroleum Resources, Paper 2010-1, p. 69-82. 4. Pembrook Mining Corporation, Vancouver, BC 5. Richfield Ventures Corporation, Quesnel, BC 6. RebelEX Resources Corporation, Vancouver, BC The Best Place on Earth Eastern Limit of Cordilleran Deformation Carbonate-hosted sulphide Zn-Pb deposits Carbonate-hosted sulphide and nonsulphide Zn-Pb occurrences Pericratonic terranes Ancestral North America: shelf and platformal facies Ancestral North America: basinal facies Slide Mountain terrane Kilometres Kilometres 300 300 100 100 200 200 0 0 Pine Point Pine Point Kechika Trough LI FAULT A N E D L T U T IN T F A INA L T U T IN T F A INA Alberta U.S.A. B.C. B.C. B.C. Yukon Yukon Alaska Cassiar platform Cassiar platform Area of figure U.S.A. CANADA Alberta N.W.T. Kootenay terrane Kootenay terrane Cariboo terrane Cariboo terrane North America shelf and platformal facies North America shelf and platformal facies Mackenzie carbonate platform Mackenzie carbonate platform MacDonald platform MacDonald platform Selwyn Basin Selwyn Basin Vancouver Vancouver Stikine terrane o 49 N o 49 N o 60 N o 50 N o 60 N o 60 N o 120 W o 120 W o 140 W o 140 W o 130 W o 130 W o 130 W CC CC CC Q Q St Q Q Study area Study area SMRT SMRT TG 3 Cordillera Extended Abstract Under favourable geological, climatic, topographic and hydrological conditions, the weathering of carbonate-hosted, sulphide deposits may result in the formation of economically significant direct replacement and/or wallrock replacement nonsulphide base metal deposits (Hitzman et al, 2003; Simandl and Paradis, 2009; Paradis et al. 2010). Nonsulphide deposits were the main source of zinc in the 19th century. Due to the development of differential flotation and other metallurgical innovations during the early 20th century, the interest of explorationists shifted to sulphide ores. For a variety of environmental and economic reasons, nonsulphide deposits are again representing attractive exploration targets; however, they are commonly overlooked. The discovery rate of nonsulphide deposits in British Columbia will depend largely on the ability of the explorationists to recognize nonsulphide zinc and lead minerals, and to understand the mobility of base metals in near surface environments and the parameters that cause their precipitation as base metal carbonates, silicates or oxides. The Cariboo terrane of central BC (Figures 1 and 2) hosts several well known base metal mineral deposits, including polymetallic Ag-Pb-Zn (±Au) veins, carbonate and sediment-hosted massive sulphides [i.e., Zn-Pb Mississippi Valley-type (MVT), sedimentary exhalative Zn-Pb-Ag (SEDEX), Besshi-type massive sulphides (VHMS)], and gold placers. Carbonate-hosted nonsulphide base metal deposits are commonly overlooked. Excellent examples of Zn-Pb sulphides and “mixed ores” (rocks consisting of sulphide and nonsulphide minerals) crop out on the Cariboo Zinc property (Figures 2 and 3). Mineralization is concentrated along a favourable northwest-trending, dolomitic belt about 8 km long (Figure 3). It consists of pervasive fine-grained sulphide and nonsulphide disseminations and aggregates forming pods and masses, sulphide- and nonsulphide-bearing quartz (±calcite) veins, and crackle breccias. Sulphides are galena, sphalerite, and trace amounts of pyrite. Nonsulphides are smithsonite, hemimorphite, cerussite, hydrozincite, and possibly anglesite. The main showings, from west to east, are Canopener, DeBasher, Flipper Creek, Dolomite Flats, Main, Gunn and Que (Figures 4, 5, 6, 7, 8 and 9). In most occurrences, the spatial continuity and/or the close spatial relationships in combination with morphological similarities between sulphide and associated nonsulphide zones suggest direct-replacement of sulphides by nonsulphide base-metal- bearing minerals. The main exposure at the Gunn showing is an excellent example of a carbonate-hosted, nonsulphide, base-metal deposit formed by the direct replacement of sulphides. The area was covered by detailed gravity survey (Luckman, 2008). The determination of physical characteristics of mineralized (Pb-Zn sulphide and nonsulphide) rocks will be useful for the design of future exploration programs and for re-interpretation of existing gravity surveys. Mineralogical, geochemical and isotope studies are underway.
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52.68°52.68°
52.95°52.95°
52.45°52.45°
120.5
8°
120.5
8°
121.2
3°
121.2
3°
121°
121°
N
Que
snel
Lak
e
Que
snel
Lak
e
(Nor
th A
rm)
(Nor
th A
rm)
Mitchell LakeMitchell Lake
Ghost Ghost
LakeLake
Cariboo r
iver
Cariboo r
iver
Cameron creek
Cameron creek
3100 road
3100 road
8400 road8400 road
Little River
Little River
Lostway
Lostway
Creek
Creek
thrustthrust
1122
33
44
55
66
7788
99
1010
PleasantPleasantValleyValley
thrustthrust
0 10km
Map areaof Fig. 3
Map areaof Fig. 3
Thrust fault
Fault Mineral occurrence
Geological contact
22
Kootenay terrane
Cariboo terrane
Snowshoe Group
Quaternary: thick alluvium
Bralco succession
Undivided Snowshoe Group
Late Proterozoic and Paleozoic
Downey succession
Mount Baker volcanic rocks
Jurassic and Cretaceous granodiorite and quartz monzonite
Mississippian granitic intrusive rocks
Early Permian diorite
Quaternary basalts
Ordovician to Mississippian
Late Proterozoic to Cambrian
Kaza Group
Isaac, Cunningham, Yankee Belle formations
Yanks Peak, Midas, Mural, Dome Creek formations
Cariboo Group
Black Stuart Group
To Barkerville
MaefordLake
GrizzlyLake
GrizzlyLakeDeBasher
LakeDeBasher
Lake
PeachLakePeachLake
To L
ikel
y
SummitLakeSummitLake
MakerLake
PeanutLakePeanutLake
NDeBasherDeBasher
CanopenerCanopenerFlipper CreekFlipper Creek
MainMain
GunnGunn
Dolomite FlatsDolomite Flats
QueQue
Granodiorite to quartz monzonite
Phyllite (silver-green)
Siltstone (greenish)
Carbonate rocks
Pelitic rocks
Schistose muscovite limestone
Well-banded grey and white limestone
Grey massive limestone
Limy dolostone-dolomitic limestone
Cream dolostone (fine-grained, massive)
Road
Bedding
Schistosity
Pb-Zn showing
Geological contact
Fault
0 500 15001000
metres ??
??
AA BB
CC DD
AA BB
CC DDNonsulphidesNonsulphides
NonsulphidesNonsulphides
Oxidized sulphidesOxidized sulphides
Oxidized sulphidesOxidized sulphides
AA BB
CC DD
SphaleriteSphalerite
GalenaGalena
GalenaGalena
GalenaGalena
QuartzQuartz
QuartzQuartz
NonsulphidesNonsulphides
NonsulphidesNonsulphides
SphaleriteSphalerite
AA
CC DD
EE FF
BB OxidizedSphalerite
Sphalerite
BariteBarite
Sphalerite
Sphalerite
AA BB
Figure 4. Dolomite Flats prospect. A) Typical outcrop exposure in the Dolomite Flats area. B) Orange-brown patches corresponding to oxidized sulphides disseminated in the dolostone. C) Fracture-filling oxidized sulphides (nonsulphide) forming boxwork texture in the dolostone. D) Close-up of fine grains and aggregates of nonsulphides and oxidized sulphides in the dolostone. Smallest subdivision on the scale corresponds to 1 mm.
Figure 5. Main prospect. A) Main trench. B) Quartz-sphalerite-galena-nonsulphide (after sphalerite) vein. C) Quartz-galena vein. D) Pod of galena, nonsulphides (cerussite) and sphalerite that forms part of a vein-breccia system.
Figure 6. Gunn showing. A) Fine-grained recrystallized white dolostone. B) Disseminated oxidized (orange) and fresh (yellowish) sphalerite in the fine-grained dolostone. C) Aggregates of fresh yellow sphalerite in the fine-grained white dolostone. D) Oxidized reddish brown sulphides (presumably sphalerite) in the white dolostone. E) Barite-galena-sphalerite vein crosscutting the dolostone (only barite is clearly visible in the photograph). F) Main Gunn excavation partially covered by snow.
Figure 7. Gunn showing. A) White to grey, translucent to transparent radiating crystals, 2-3 mm in length (probably cerussite). B) Stubby white transparent crystals (probably anglesite)lining cavities. Scale is in millimetres.
Figure 8. Que showing. A) Shallow exploration trenches (arrow), stripped outcrops and subcrops. B) Close-up view of nonsulphide minerals (orange and white). C) Large angular nonsulphide-bearing blocks. D) Radiating tabular translucent crystals of cerussite in cavity. Scale is in millimetres.
Figure 1. Location of the Cariboo terrane and the study area (Cariboo Zinc property)with respect to other significant carbonate-hosted sulphide and nonsulphide occurrences in the northern cordillera (modified from Nelson et al., 2002, 2006). Abbreviations: St - Stikine terrane, CC - Cache Creek, Q - Quesnel terrane, SMRT - southern Rocky Mountain trench.
Figure 2. Regional geological setting of the study area (after Campbell, 1978; Struik, 1983a, b, 1988; Ferri and O’Brien, 2003), east-central BC. The dotted rectangle is the area covered by Figure 3. Mineral occurrences, according to BC MINFILE (BCGS, 2009): 1 - Sil (corresponds to the Gunn and Que showings in this study), 2 - Grizzly Lake (corresponds to the Flipper Creek, Dolomite Flats, and Main showings in this study), 3 - Lam (corresponds to the DeBasher showing in this study), 4 - Comin Throu Bear, 5 - Maybe, 6 - Mt Kimball, 7 - Maeford Lake, 8 - Ace, 9 - Mae, 10 - Cariboo Scheelite. Occurrences 1, 2, and 3 form the Cariboo Zinc property.
Figure 3. Geology of the Cariboo Zinc property area showing the location of the Canopener, DeBasher, Flipper Creek, Dolomite Flats, Main, Gunn, and Que showings (from Lormand and Alford, 1990).
Figure 9. Galena nodules discovered in a north-flowing stream less than 50 m upstream from high-grade nonsulphide boulders shown on Figure 8c (Que showing).
SummaryCarbonate-hosted nonsulphide Pb-Zn deposits of south-eastern BC (Figure 1) were covered bySimandl and Paradis (2009). This present study demonstrates that nonsulphide Pb-Zn depositscan be found much further north than previously anticipated. Results of ongoing mineralogical,geochemical, and isotopic studies will contribute to a better understanding of these deposits. Estimates of physical properties of nonsulphide-bearing rocks may help exploration programs and drill target selection.
Characteristics of Cariboo zinc occurrences
Host rocks: Fine-grained cream-coloured dolostone and limy dolostone.
Texture/structure: Sulphide and nonsulphide Pb-Zn minerals occur as disseminations, replacement zones, and fracture-, vein- and breccia-fillings.
Ore mineralogy:Sulphides = galena, sphalerite and trace amounts of pyrite.Nonsulphides = smithsonite, hemimorphite, cerussite, hydrozincite and anglesite (?).Gangue minerals = dolomite, calcite, quartz, and locally barite.
Alteration: Dolomitization and silicification pre-dating, or contemporaneous with sulphides and pre-dating Pb-Zn nonsulphides.
Ore controls:
• Pb-Zn occurs along a SE-trending belt about 8 km long. It is confined to a stratabound
zone restricted to dolomitic carbonates, adjacent to phyllite.
• Historical reports suggest that Pb-Zn mineralization is largely fault-controlled; however we
were unable to confirm this control during our short visit.
• Nonsulphides are derived from sulphide mineralization in the near surface environment.
At depth, nonsulphide mineralization may be limited by the level of the water table. Karst may be present in the area; however, its importance as an ore control remains to be confirmed.
Suggested reference: Paradis, S., Simandl, G.J., Bradford, J., Leslie, C. and Brett, C. (2010): Carbonate-hosted sulphide and nonsulphide Pb-Zn Mineralization, Cariboo terrane, British Columbia; British Columbia Ministry of Energy, Mines and Petroleum Resources; Geofile 2010-4, poster.
Carbonate-hosted sulphide and nonsulphide Pb-Zn mineralization, Cariboo terrane, BC, Canada1,3 2,3 4 5 6Suzanne Paradis , George J. Simandl , John Bradford , Christopher Leslie , Curtis Brett
2. British Columbia Ministry of Energy, Mines and Petroleum Resources, Victoria, BC3. University of Victoria, School of Earth and Ocean Sciences, Victoria, BC
1. Geological Survey of Canada, Sidney, BC
References:For complete list of references, please consult: Paradis, S., Simandl, G.J., Bradford, J., Leslie, C. and Brett, C. (2010): Carbonate-hosted lead-zinc mineralization on the Cariboo zinc property, Quesnel Lake area, east-central British Columbia (NTS 093A/14E, 15W); in: Geological Fieldwork 2009, BC Ministry of Energy and Mines and Petroleum Resources, Paper 2010-1, p. 69-82.
4. Pembrook Mining Corporation, Vancouver, BC 5. Richfield Ventures Corporation, Quesnel, BC6. RebelEX Resources Corporation, Vancouver, BCThe Best Place on Earth
Eastern
Lim
itof
Cord
illera
nD
efo
rmatio
n
Carbonate-hosted sulphide Zn-Pb deposits
Carbonate-hosted sulphide and nonsulphide Zn-Pb occurrences
Pericratonic terranes
Ancestral North America:shelf and platformal facies
Ancestral North America:basinal facies
Slide Mountain terrane
KilometresKilometres
300300100100 20020000
PinePointPinePoint
KechikaTrough
LIFAU
LT
ANED
LTU
TINT
FA
INA
LTU
TINT
FA
INA
Alb
erta
U.S.A.B.C.
B.C.B.C.
YukonYukon
Alaska
Cass ia r
p l a t f o rm
Cass ia r
p l a t f o rm
Area offigure
U.S.A.CANADA
AlbertaN.W.T.
Kootenayterrane
Kootenayterrane
CaribooterraneCaribooterrane
North America shelf and
platformal facies
North America shelf and
platformal facies
Mackenzie carbonate platform
Mackenzie carbonate platform
MacDonaldplatform
MacDonaldplatform
SelwynBasin
SelwynBasin
VancouverVancouver
Stikineterrane
o
49 No
49 N
o60 N
o50 N
o
60 No
60 N
o120 Wo120 Wo140 Wo140 Wo130 Wo130 W
o13
0W
CC
CC
CC Q
Q
St
Q
Q
Study areaStudy area
SMRT
SMRT
TG3
Cordillera
Extended Abstract Under favourable geological, climatic, topographic and hydrological condit ions, the weather ing of carbonate-hosted, sulphide deposits may result in the formation of economically significant direct replacement and/or wallrock replacement nonsulphide base metal deposits (Hitzman et al, 2003; Simandl and Paradis, 2009; Paradis et al.
2010). Nonsulphide deposits were the main source of zinc in the 19th century. Due to the
development of dif ferential flotation and other metallurgical innovat ions during the ear ly 20th century, the interest of explorationists shifted to sulphide ores. For a var iety of environmental and economic reasons, nonsulphide deposits are again representing attractive exploration targets; however, they are commonly overlooked. The discovery rate of nonsulphide deposits in Br itish Columbia will depend largely on the abi lity of the explorationists to recognize nonsulphide zinc and lead minerals, and to understand the mobility of base metals in near surface environments and the parameters that cause their precipitat ion as base metal carbonates, silicates or oxides. The Cariboo terrane of central BC (Figures 1 and 2) hosts several wel l known base metal mineral deposits, including polymetal lic Ag-Pb-Zn (±Au) veins, carbonate and sediment-hosted massive sulphides [i.e., Zn-Pb Mississippi Valley-type (MVT), sedimentary exhalative Zn-Pb-Ag (SEDEX), Besshi-type massive sulphides (VHMS)], and gold placers. Carbonate-hosted nonsulphide base metal deposits are commonly over looked. Excellent examples of Zn-Pb sulphides and “mixed ores” (rocks consisting of sulphide and nonsulphide minerals) crop out on the Cariboo Zinc property (Figures 2 and 3). Mineral ization is concentrated along a favourable northwest-trending, dolomitic belt about 8 km long (Figure 3). It consists of pervasive fine-grained sulphide and nonsulphide disseminations and aggregates forming pods and masses, sulphide- and nonsulphide-bearing quartz (±calcite) veins, and crackle breccias. Sulphides are galena, sphaler ite, and trace amounts of pyr ite. Nonsulphides are smithsonite, hemimorphite, cerussite, hydrozincite, and possibly anglesite. The main showings, from west to east, are Canopener, DeBasher, Flipper Creek, Dolomite Flats, Main, Gunn and Que (Figures 4, 5, 6, 7, 8 and 9). In most occurrences, the spatial continuity and/or the close spatial relat ionships in combination with morphological similari ties between sulphide and associated nonsulphide zones suggest direct-replacement of sulphides by nonsulphide base-metal-bearing minerals. The main exposure at the Gunn showing is an excel lent example of a carbonate-hosted, nonsulphide, base-metal deposit formed by the direct replacement of sulphides. The area was covered by detai led gravity survey (Luckman, 2008). The determination of physical characteristics of mineralized (Pb-Zn sulphide and nonsulphide) rocks will be useful for the design of future explorat ion programs and for re-interpretation of existing gravity surveys. Mineralogical, geochemical and isotope studies are underway.
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