Structural geology of the Nadaleen Trend, …...Structural geology of the Nadaleen Trend,...
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Structural geology of the Nadaleen Trend, northeastern Yukon Territory, Canada: Implications for recent Au discoveries Justin C. Palmer and Yvette D. Kuiper Department of Geology and Geological Engineering, Colorado School of Mines MINES 1. Abstract 4. Local Structural Geology 2. Regional Location 3. Geologic Map and Stratigraphy 7. Acknowledgements • • • • • • • Conrad Limestone Osiris Limestone Northern Siliciclastic Rocks Osiris Debrite Osiris Shale ? ? Nadaleen Fault Rocks Conrad Siliciclastic Rocks Black Shale Carbonate Conglomerate Grey Shale Osiris Dolostone Limestone Grit Gabbro Recent Au discoveries in the eastern Nadaleen Trend of northeastern Yukon Territory are hosted in strongly deformed, unmetamorphosed, Neoproterozoic carbonate and siliciclastic rocks and display characteristics similar to Carlin-type deposits in Nevada. The complicated structural geology primarily results from mid-Cretaceous, thin-skinned fold-thrust deformation imposed upon a mechanically heterogeneous package of sedimentary rocks. Four generations of deformation resulted in tilting of stratigraphy to the SSW (D1), several moderately- to steeply-SSW-, SW- and E-plunging hundred-meter scale chevron folds and the E-trending dextral Osiris Fault (D2), the N-dipping reverse Nadaleen Fault zone (D3), and the N-trending dextral Conrad Fault (D4). Similar combinations of structures have not been recognized regionally, perhaps because the Nadaleen Trend is located in a zone of regional stratigraphic and structural transitions. Neoproterozoic- and Paleozoic-aged platform rocks occur west and north of the Nadaleen Trend; similarly aged basinal rocks occur to the east and south. Regionally extensive east-trending thrust faults, including the Dawson Thrust and Kathleen Lakes Fault, end within 10 km of the Nadaleen Trend. The combination of S-vergent thrust faults at and north of the Nadaleen Trend, and N-vergent thrust faults elsewhere in the region have the geometry of an E-trending triangle zone across the Nadaleen Trend. We suggest that these geologic transitions reflect the influence of a previously unrecognized, south-dipping basement normal fault (the Rackla Fault) that occurs west of the Nadaleen Trend and terminates below it. This fault is interpreted to have enough offset west of the Nadaleen Trend to obstruct north-directed fold-thrust movement, resulting in a lack of significant shortening to the north. The triangle zone is interpreted as a result of north-directed motion interacting with and overriding the minor obstruction at the eastern end of the Rackla Fault. Overriding the obstruction may have led to tectonic wedging and backthrusting. East of the Nadaleen Trend, fold-thrust movement was unobstructed. Antiformal SSW-plunging D2 structures host the Conrad, Osiris, and Isis East Au zones within the eastern Nadaleen Trend. The folds are oriented oblique to the general easterly trend of folds and thrust faults in the region. Their oblique orientation perhaps made them act as locally favorable channels for upwelling ore fluids, while the E-trending triangle zone across the Nadaleen Trend may have acted as a more regional structural funnel. 5. Regional Structural Geology 6. Conclusions 200 km Na d a l e e n R i v e r K athle en L a k e s F a ult S t e w a r t R i v e r D a w s o n T h r u s t D a w s on T h r u st 106C/02 106B/04 64˚ N 132˚ 30’ W 132˚ 00’ W 131˚ 30’ W 64˚ 15’ N 106C/01 133˚ 00’ W Mackenzie Platform Selwyn Basin Platform Basin 10 km N Carlin-type Au N Yukon Territory British Columbia Alaska Au zone name Major Fault Fault Stragraphic Osiris Fault Conrad Fault 629500 630000 630500 629500 630000 630500 7112000 7112500 7113000 7112000 7112500 7113000 500 m N Algae Narchilla Nadaleen Gametrail Sheepbed Ice Brook/ Twitya Yusezyu WINDERMERE SUPERGROUP HYLAND GROUP CRYOGENIAN EDIACARAN LOWER CAMBRIAN Thinly bedded, rusty weathering, mudstone to siltstone with interbed- ded conglomerate units Grey weathering, granular to massive, weathering resistant silty limestone Rusty weathering, fine-grained shale/siltstone with interbedded quartz pebble conglomerate and thin, massive pyrite layers Black weathering shale with inter- bedded carbonate lenses Megaclastic, tan- to grey-colored, normally graded carbonate con- glomerate Grey weathering shale Maroon and locally green weathering shale Grey and yellowish-orange weather- ing silty limestone and interbedded rudstone Grey weathering massive dolostone Tan to grey weathering polymictic conglomerate Brown weathering gritty limestone Domain Boundary Mackenzie Platform Selwyn Basin Osiris The regional stratigraphic domain map above shows the regional geologic associations as interpreted by Yukon Geological Survey (2013, 2014). The Anubis, Conrad, Osiris, and Isis East gold zones form the Nadaleen Trend (black ellipse). Through detailed geologic mapping, this study was aimed at understanding both (1) the structural geology of the eastern Nadaleen Trend (red box) and (2) the regional setting of the structures. The broad aim of the study was to determine if structures caused gold to localize in the study area. Proterozoic Paleozoic Regional Setting Age Stratigraphic Group Stratigraphic Formation Generalized Facies Conrad Isis East Anubis The geologic map above shows the general locations of fold axial traces, fault traces, and Au zones (bold italics). Three faults exist: the reverse Nadaleen Fault and the strike-slip Osiris and Conrad faults. Five map scale folds exist; three of which host the Conrad, Osiris, and Isis East Au zones. Colpron et al., 2013 Moynihan et al., 2014 Colpron et al., 2013; Moynihan et al., 2014 Osiris Fault Conrad Fault 629500 630000 630500 629500 630000 630500 7112000 7112500 7113000 7112000 7112500 7113000 Explanation 500 m N ESE-directed, subhor- izontal folds WSW-plunging folds E-plunging folds SSW-plunging folds SE-plunging folds 1. Observation The geologic map of the eastern Nadaleen Trend to the right is separated into domains (black polygons) that correspond to areas defined by unique structural orientations. Structural measurements are displayed on equal-area, lower hemisphere projections and colored based on similar orientations. 500 m N Proto-Osiris Fault 500 m N The area hosts moderately WSW-plunging folds (orange), moderately E-plunging folds (purple), shallowly to moderately SE-plunging folds (blue), moderately to steeply SSW-plunging folds (yellow), and SSE-directed, subhorizontal folds (green) as well as generally planar bedding (white). Open to tight chevron folds occur at all scales. The Conrad, Osiris, and Isis East Au zones are all hosted within moderately to steeply SSW-plunging folds. Fracture and stylolitic cleavage is common to fine-grained siliciclastic and carbonate units, respectively. 2. Interpretation 500 m N 500 m N D1 Early D2 Late D2 D3 Symbology Pole to bedding Pole to cleavage Hinge Line The sequence to the right shows our interpretation of the structural evolution of rocks of the Nadaleen Trend. Letters show similar locations from early D2 to late D2. D1: NNE-directed shortening Early D2: NW-directed, dextral simple shear Late D2: Continued NW- directed dextral simple shear D3: NNE-directed shortening We interpret that early D 2 (NW-directed shortening) shortened the rock package to a breaking point at which the Osiris Fault formed, displacing strata to the east. Complex structural orientations throughout the area may be the result of rotation, translation, and thickening exploiting competency contrasts between relatively strong limestone units and weaker shale units. A B D C A’ B’ D’ C’ Rackla Fault Trend of Major Thrust Faults (right-hand rule) 5 13 8 1 8 3 10 km 106C/02 106B/04 64˚ N 133˚ 00’ W 132˚ 30’ W 132˚ 00’ W 131˚ 30’ W 64˚ 15’ N 106C/01 N Mackenzie Platform Selwyn Basin Platform Basin Colpron et al., 2013 Moynihan et al., 2014 Proterozoic Paleozoic N- to NE-vergent thrust faults S-vergent thrust faults 1. Observation Overlap Assemblage Upper Plate Dawson Fault Nadaleen Area North of Nadaleen Northeast Nadaleen Eastern Nadaleen D a w s o n T h r u s t S t e w a r t R i v e r K athle e n La k e s F a ul t N a d a le e n R i v e r D a w s o n T h r u s t West Middle East Overlap Assemblage Upper Plate Dawson Thrust North of Nadaleen Northeast Nadaleen Eastern Nadaleen Nadaleen Area R a c k la F ault Two dominant directions of vergence: 1. S-vergent thrusts generally at and north of the Nadaleen Area 2. N- to NW-vergent thrusts generally west, south, and east of the Nadaleen Area Northward transition west of the Nadaleen Area 1. 0 thrusts in the Northwest domain 2. 5 thrusts in the Overlap Assemblage 3. 13 imbricate thrusts in Upper Plate Dawson Fault Eest of the Nadaleen Area 1. N- to NE-vergent thrusts throughout Eastern Nadaleen Subsurface Schematic N- to NE-vergent thrusts S-vergent thrusts No thrust faults Interpreted Rackla Fault trace Structural domain boundary 2. Interpretation Triangle zone across Nadaleen Trend N- to NW-vergent thrust faults to the south and S-vergent thrust faults to the north suggests ‘triangle zone’ geometry across the Nadaleen Trend similar to the geometry in the figure to the right. A triangle zone could have acted as a structural funnel for Au-rich ore fluids. Rackla Fault Regional-scale transitions that occur near the Nadaleen Area: 1. Eastern termination of the Dawson Thrust and Kathleen Lakes Fault 2. Termination of Mackenzie Platform and beginning of Selwyn Basin to the east and south 3. Eastern termination of Paleozoic platform and basin rocks 4. Transition from N- to NW-vergent thrust faults throughout the region to S-vergent thrust faults These large scale transitions are interpreted to have been influenced by a previously unrecognized subsurface normal fault, the “Rackla Fault,” that is interpreted to end below the Nadaleen Area (figure above). The magnitude of offset along the Rackla Fault west of the Nadaleen Area may have obstructed N-directed fold thrust movement, resulting in no thrust faults north of the Overlap Assemblage. In the Nadaleen Area, the Rackla Fault is interpreted as a small barrier; overriding the barrier during continued N-directed thrusting detached rocks in the foreland through wedging, thrusting them to the south. Unobstructed thrusting occurs east of the Nadaleen Area. The stratigraphic domain map to the right is separated into structural domains (red lines, white labels) with unique structural orientations to show the trends of thrust faults in the Nadaleen region. Thrust fault trends are shown as colored rose diagrams in the domains; colors correspond to unique directions of vergence. The number in the rose diagram corresponds to the number of thrusts mapped. No thrust faults were mapped in the Northwest domain. Local Large-scale structural features include: 1. Several hundred-meter scale, open to tight chevron folds that plunge moderately to steeply to the SSW, SW, and E. 2. The E-trending dextral strike-slip Osiris Fault 3. The steeply NNE-dipping Nadaleen Fault zone Interpreted deformation events D1: NNE-directed shortening D2: NW-directed shortening D3: N-S directed shortening Regional Structural features: 1. N- to NE-vergent thrust faults west, south, and east of Nadaleen Area 2. S-vergent thrust fault at and north of Nadaleen Area Interpretation 1. The Nadaleen Area lies in the center of a triangle zone. 2. The Rackla Fault caused obstruction of thrusting to the west of, formation of a triangle at, and unobstructed movement east of the Nadaleen Area Rob and Joan Carne and Julia Lane are graciously thanked for their constant good advice and humor in the field, and for supporting the master’s thesis project. Odin Christensen is thanked for his advice and support in the field. We thank Venessa Bennett for her contact with ATAC Re- sources and for our field introduction. Archer Cathro & Associates (1981) Ltd. and ATAC Resources Ltd. are thanked for their outstanding support in camp and for their generous financial support. We thank Society of Economic Geologists for monetary support throughout this project. 8. References MacKay, P.A., 1996, The Highwood Structure: A tectonic wedge at the foreland edge of the southern Canadian Cordillera: Bulletin of Canadian Petroleum Geology, v. 44, p. 215-232. Colpron, M., Moynihan, D., Israel, S., and Abbott, G., 2013, Bedrock geology of the Rackla belt (106C/1-4 and 106D/1), southern Nadaleen map area, Yukon Geological Survey: Poster presented at 2013 AME BC Mineral Exploration Roundup Conference, Vancouver, B.C., Janu- ary 28-31, 2013. Moynihan, D., Colpron, M., Israel, S., and Abbott, G., 2014, Geology of the eastern Rackla Belt, east-central Yukon, Yukon Geological Survey: Poster presented at 2014 Mineral Explora- tion Roundup Conference, Vancouver, B.C., January 27-30, 2014. The map in section 3 is a close-up of the red box in the figure above. Nadaleen Trend Map in next section Conrad Osiris Isis East Northwest 63 60 75 74 65 Lower Upper Detachment Detachment Hinterland Foreland Triangle Zone Schematic Northwest MacKay, 1996 70 60 65 80 85 45 63 27 52 79 33 79 83
Transcript of Structural geology of the Nadaleen Trend, …...Structural geology of the Nadaleen Trend,...
Structural geology of the Nadaleen Trend, northeastern Yukon Territory, Canada:Implications for recent Au discoveries
Justin C. Palmer and Yvette D. KuiperDepartment of Geology and Geological Engineering, Colorado School of MinesMINES
1. Abstract
4. Local Structural Geology
2. Regional Location 3. Geologic Map and Stratigraphy
7. Acknowledgements
••
•
• •
•
•
ConradLimestone
OsirisLimestone
NorthernSiliciclastic
Rocks
Osiris Debrite
Osiris Shale??
NadaleenFault Rocks
ConradSiliciclastic
Rocks
Black Shale
CarbonateConglomerate
GreyShale
OsirisDolostone
LimestoneGrit
Gabbro
Recent Au discoveries in the eastern Nadaleen Trend of northeastern Yukon Territory are hosted in strongly deformed, unmetamorphosed, Neoproterozoic carbonate and siliciclastic rocks and display characteristics similar to Carlin-type deposits in Nevada. The complicated structural geology primarily results from mid-Cretaceous, thin-skinned fold-thrust deformation imposed upon a mechanically heterogeneous package of sedimentary rocks. Four generations of deformation resulted in tilting of stratigraphy to the SSW (D1), several moderately- to steeply-SSW-, SW- and E-plunging hundred-meter scale chevron folds and the E-trending dextral Osiris Fault (D2), the N-dipping reverse Nadaleen Fault zone (D3), and the N-trending dextral Conrad Fault (D4). Similar combinations of structures have not been recognized regionally, perhaps because the Nadaleen Trend is located in a zone of regional stratigraphic and structural transitions. Neoproterozoic- and Paleozoic-aged platform rocks occur west and north of the Nadaleen Trend; similarly aged basinal rocks occur to the east and south. Regionally extensive east-trending thrust faults, including the Dawson Thrust and Kathleen Lakes Fault, end within 10 km of the Nadaleen Trend. The combination of S-vergent thrust faults at and north of the Nadaleen Trend, and N-vergent thrust faults elsewhere in the region have the geometry of an E-trending triangle zone across the Nadaleen Trend. We suggest that these geologic transitions re�ect the in�uence of a previously unrecognized, south-dipping basement normal fault (the Rackla Fault) that occurs west of the Nadaleen Trend and terminates below it. This fault is interpreted to have enough o�set west of the Nadaleen Trend to obstruct north-directed fold-thrust movement, resulting in a lack of signi�cant shortening to the north. The triangle zone is interpreted as a result of north-directed motion interacting with and overriding the minor obstruction at the eastern end of the Rackla Fault. Overriding the obstruction may have led to tectonic wedging and backthrusting. East of the Nadaleen Trend, fold-thrust movement was unobstructed.
Antiformal SSW-plunging D2 structures host the Conrad, Osiris, and Isis East Au zones within the eastern Nadaleen Trend. The folds are oriented oblique to the general easterly trend of folds and thrust faults in the region. Their oblique orientation perhaps made them act as locally favorable channels for upwelling ore �uids, while the E-trending triangle zone across the Nadaleen Trend may have acted as a more regional structural funnel.
5. Regional Structural Geology 6. Conclusions
200 km
Nadaleen Rive r
Kathleen Lakes Fault
Stewa rt River
Dawson Thrust
Da wson Thrust
106C/02 106B/0464˚ N
132˚ 30’ W 132˚ 00’ W 131˚ 30’ W64˚ 15’ N
106C/01
133˚ 00’ W
Mackenzie Platform
Selwyn Basin
Platform
Basin
10 kmNCarlin-type Au
N
Yukon Territory
British Columbia
Alas
ka
Au zone name
Major FaultFaultStratigraphic
Osiris Fault
ConradFault
629500 630000 630500
629500 630000 630500
7112
000
7112
500
7113
000
7112
000
7112
500
7113
000
500 m
N
Algae
Narchilla
Nadaleen
Gametrail
SheepbedIce Brook/Twitya
Yusezyu
WIN
DER
MER
E SU
PER
GR
OU
PH
YLA
ND
GR
OU
P
CRYO
GEN
IAN
EDIA
CARA
NLO
WER
CA
MBR
IAN
Thinly bedded, rusty weathering, mudstone to siltstone with interbed-ded conglomerate units
Grey weathering, granular to massive, weathering resistant silty limestone
Rusty weathering, �ne-grained shale/siltstone with interbedded quartz pebble conglomerate and thin, massive pyrite layers
Black weathering shale with inter-bedded carbonate lenses
Megaclastic, tan- to grey-colored, normally graded carbonate con-glomerate
Grey weathering shale
Maroon and locally green weathering shale
Grey and yellowish-orange weather-ing silty limestone and interbedded rudstone
Grey weathering massive dolostone
Tan to grey weathering polymictic conglomerate
Brown weathering gritty limestone
Domain Boundary
Mac
kenz
ie P
latf
orm
Selw
yn B
asin
Osiris
The regional stratigraphic domain map above shows the regional geologic associations as interpreted by Yukon Geological Survey (2013, 2014). The Anubis, Conrad, Osiris, and Isis East gold zones form the Nadaleen Trend (black ellipse). Through detailed geologic mapping, this study was aimed at understanding both (1) the structural geology of the eastern Nadaleen Trend (red box) and (2) the regional setting of the structures. The broad aim of the study was to determine if structures caused gold to localize in the study area.
Proterozoic Paleozoic
Regional Setting
AgeStra
tigraphic Group
Stratig
raphic Formatio
n
Generalized
F
acies
Conrad
Isis East
Anubis
The geologic map above shows the general locations of fold axial traces, fault traces, and Au zones (bold italics). Three faults exist: the reverse Nadaleen Fault and the strike-slip Osiris and Conrad faults. Five map scale folds exist; three of which host the Conrad, Osiris, and Isis East Au zones.
Colpron et al., 2013Moynihan et al., 2014
Colpron et al., 2013; Moynihan et al., 2014
Osiris Fault
ConradFault
629500 630000 630500
629500 630000 630500
7112
000
7112
500
7113
000
7112
000
7112
500
7113
000
Explanation500 mN
ESE-directed, subhor-izontal folds
WSW-plunging folds
E-plunging folds
SSW-plunging folds
SE-plunging folds
1. Observation
The geologic map of the eastern Nadaleen Trend to the right is separated into domains (black polygons) that correspond to areas de�ned by unique structural orientations. Structural measurements are displayed on equal-area, lower hemisphere projections and colored based on similar orientations.
500 m N
Proto-Osiris Fault
500 m N
The area hosts moderately WSW-plunging folds (orange), moderately E-plunging folds (purple), shallowly to moderately SE-plunging folds (blue), moderately to steeply SSW-plunging folds (yellow), and SSE-directed, subhorizontal folds (green) as well as generally planar bedding (white). Open to tight chevron folds occur at all scales. The Conrad, Osiris, and Isis East Au zones are all hosted within moderately to steeply SSW-plunging folds. Fracture and stylolitic cleavage is common to �ne-grained siliciclastic and carbonate units, respectively.
2. Interpretation
500 m N500 m N
D1 EarlyD2
LateD2
D3
SymbologyPole to beddingPole to cleavageHinge Line
The sequence to the right shows our interpretation of the structural evolution of rocks of the Nadaleen Trend. Letters show similar locations from early D2 to late D2.
D1: NNE-directed shortening Early D2: NW-directed, dextral simple shear Late D2: Continued NW- directed dextral simple shear D3: NNE-directed shortening
We interpret that early D 2 (NW-directed shortening) shortened the rock package to a breaking point at which the Osiris Fault formed, displacing strata to the east. Complex structural orientations throughout the area may be the result of rotation, translation, and thickening exploiting competency contrasts between relatively strong limestone units and weaker shale units.
A
BD
C
A’
B’ D’
C’
Rackla Fault
Trend of Major Thrust Faults (right-hand rule)
5
13
8
1
8
3
10 km
106C/02106B/04
64˚ N
133˚ 00’ W 132˚ 30’ W 132˚ 00’ W 131˚ 30’ W64˚ 15’ N
106C/01
N
Mackenzie Platform
Selwyn Basin
Platform
Basin
Colpron et al., 2013Moynihan et al., 2014
Proterozoic PaleozoicN- to NE-vergent thrust faults S-vergent thrust faults
1. Observation
Overlap Assemblage
Upper Plate Dawson Fault
Nadaleen Area
North of Nadaleen Northeast Nadaleen
Eastern NadaleenDawson Thrust
Stewart River
Kathleen Lakes Fault
Nadaleen River
Dawson Thrust
WestMiddle
East
OverlapAssemblage
Upper PlateDawson Thrust
North ofNadaleen
NortheastNadaleen
EasternNadaleenNadaleen
AreaRackla Fault
Two dominant directions of vergence:1. S-vergent thrusts generally at and north of the Nadaleen Area2. N- to NW-vergent thrusts generally west, south, and east of the Nadaleen Area
Northward transition west of the Nadaleen Area1. 0 thrusts in the Northwest domain2. 5 thrusts in the Overlap Assemblage3. 13 imbricate thrusts in Upper Plate Dawson Fault
Eest of the Nadaleen Area1. N- to NE-vergent thrusts throughout Eastern Nadaleen
Subsurface Schematic
N- to NE-vergent thrusts
S-vergent thrusts
No thrust faults
Interpreted Rackla Fault traceStructural domain boundary
2. InterpretationTriangle zone across Nadaleen Trend N- to NW-vergent thrust faults to the south and S-vergent thrust faults to the north suggests ‘triangle zone’ geometry across the Nadaleen Trend similar to the geometry in the �gure to the right. A triangle zone could have acted as a structural funnel for Au-rich ore �uids.
Rackla FaultRegional-scale transitions that occur near the Nadaleen Area: 1. Eastern termination of the Dawson Thrust and Kathleen Lakes Fault 2. Termination of Mackenzie Platform and beginning of Selwyn Basin to the east and south 3. Eastern termination of Paleozoic platform and basin rocks 4. Transition from N- to NW-vergent thrust faults throughout the region to S-vergent thrust faults
These large scale transitions are interpreted to have been in�uenced by a previously unrecognized subsurface normal fault, the “Rackla Fault,” that is interpreted to end below the Nadaleen Area (�gure above).
The magnitude of o�set along the Rackla Fault west of the Nadaleen Area may have obstructed N-directed fold thrust movement, resulting in no thrust faults north of the Overlap Assemblage.
In the Nadaleen Area, the Rackla Fault is interpreted as a small barrier; overriding the barrier during continued N-directed thrusting detached rocks in the foreland through wedging, thrusting them to the south.
Unobstructed thrusting occurs east of the Nadaleen Area.
The stratigraphic domain map to the right is separated into structural domains (red lines, white labels) with unique structural orientations to show the trends of thrust faults in the Nadaleen region. Thrust fault trends are shown as colored rose diagrams in the domains; colors correspond to unique directions of vergence. The number in the rose diagram corresponds to the number of thrusts mapped. No thrust faults were mapped in the Northwest domain.
Local Large-scale structural features include:1. Several hundred-meter scale, open to tight chevron folds that plunge moderately to steeply to the SSW, SW, and E.2. The E-trending dextral strike-slip Osiris Fault3. The steeply NNE-dipping Nadaleen Fault zone
Interpreted deformation eventsD1: NNE-directed shorteningD2: NW-directed shorteningD3: N-S directed shortening
Regional Structural features:1. N- to NE-vergent thrust faults west, south, and east of Nadaleen Area2. S-vergent thrust fault at and north of Nadaleen Area
Interpretation1. The Nadaleen Area lies in the center of a triangle zone.2. The Rackla Fault caused obstruction of thrusting to the west of, formation of a triangle at, and unobstructed movement east of the Nadaleen Area
Rob and Joan Carne and Julia Lane are graciously thanked for their constant good advice and humor in the �eld, and for supporting the master’s thesis project. Odin Christensen is thanked for his advice and support in the �eld. We thank Venessa Bennett for her contact with ATAC Re-sources and for our �eld introduction. Archer Cathro & Associates (1981) Ltd. and ATAC Resources Ltd. are thanked for their outstanding support in camp and for their generous �nancial support. We thank Society of Economic Geologists for monetary support throughout this project.
8. ReferencesMacKay, P.A., 1996, The Highwood Structure: A tectonic wedge at the foreland edge of the southern Canadian Cordillera: Bulletin of Canadian Petroleum Geology, v. 44, p. 215-232.Colpron, M., Moynihan, D., Israel, S., and Abbott, G., 2013, Bedrock geology of the Rackla belt (106C/1-4 and 106D/1), southern Nadaleen map area, Yukon Geological Survey: Poster presented at 2013 AME BC Mineral Exploration Roundup Conference, Vancouver, B.C., Janu-ary 28-31, 2013. Moynihan, D., Colpron, M., Israel, S., and Abbott, G., 2014, Geology of the eastern Rackla Belt, east-central Yukon, Yukon Geological Survey: Poster presented at 2014 Mineral Explora-tion Roundup Conference, Vancouver, B.C., January 27-30, 2014.
The map in section 3 is a close-up of the red box in the �gure above.
Nadaleen Trend
Map in next section
Conrad
Osiris
Isis East
Northwest
63
60
75
74
65
Lower
Upper
Detachment
Detachment
Hinterland Foreland
Triangle Zone Schematic
Northwest
MacKay, 1996
70
60
65
80
85
45
63
27 52
79
3379
83
