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Saskatchewan Geological Survey 1 Summary of Investigations 2013,
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Bedrock Geology of the Northern Janice Lake and Burbidge Lake
Areas, Wollaston Domain (parts of NTS 74A/14 and /15)
J. Fetter
Fetter, J. (2013): Bedrock geology of the northern Janice Lake
and Burbidge Lake areas, Wollaston Domain (parts of NTS 74A/14 and
74A/15); in Summary of Investigations 2013, Volume 2, Saskatchewan
Geological Survey, Sask. Ministry of the Economy, Saskatchewan
Geological Survey, Misc. Rep. 2013-4.2, Paper A-5, 18p.
This report is accompanied by the map separate(s) entitled:
Fetter, J. (2013): Bedrock geology of the northern Janice Lake
area, Wollaston Domain (parts of NTS 74A/15); 1:20 000-scale
preliminary geology map with Summary of Investigations 2013, Volume
2, Saskatchewan Geological Survey, Sask. Ministry of the Economy,
Misc. Rep. 2013-4.2-(2.1). __________ (2013): Bedrock geology of
the Burbidge Lake area, Wollaston Domain (parts of NTS 74A/14 and
/15); 1:20 000- scale preliminary geology map with Summary of
Investigations 2013, Volume 2, Saskatchewan Geological Survey,
Sask. Ministry of the Economy, Misc. Rep. 2013-4.2-(2.2).
Abstract The Janice-Burbidge lakes area, within the east-central
Wollaston Domain, is underlain by a thick succession of
northeast-trending, variably deformed and metamorphosed, arkose,
calc-silicate–bearing siliciclastic rocks, fanglomerate,
conglomerate, and wacke of the Rafuse Lake and Janice Lake
formations. Higher metamorphic grade rocks on southwestern Burbidge
Lake are composed of psammopelite and minor pelite of the Bole Bay
Formation. A variety of granitoid to pegmatitic dykes have intruded
the supracrustal rocks.
Five episodes of deformation and have affected the rocks. D1
resulted in the development of a foliation (S1) of variable
intensity. S1 has mostly been transposed parallel to compositional
layering, and therefore is believed to be a composite foliation. D2
formed tight to isoclinal F2 folds. D3, which produced the main
structural style, is characterized by tight to isoclinal
northeast-trending, doubly plunging F3 folds. A pervasive, steep,
dominantly northwest-dipping axial planar S3 foliation commonly has
transposed earlier S0/S1/S2 fabrics. D4 formed northwest-trending,
upright folds, expressed as a weak crenulation on S3. D4 was
relatively weak and had little effect on the regional structural
trends. D5 produced widespread brittle faults, which mainly trend
north to northwest and crosscut all of the earlier structures.
Two Hudsonian metamorphic events, M1 and M2, are distinguished
based on textural relationships between the similar metamorphic
minerals of different generations. M1 began before the peak of D1
deformation and ended during D2 deformation and M2 was broadly
coeval with, and outlasted, D3 deformation. Lower amphibolite
facies conditions within the arkoses of the Janice Lake and Rafuse
Lake formations occurred during M1, as indicated by the presence of
garnet, biotite, and hornblende. Partial melts are found locally,
possibly associated with M2 suggesting middle to upper amphibolite
facies. Metamorphic grade reached upper amphibolite facies
northwest of Burbidge Lake as indicated by the stability of
sillimanite, cordierite, and K-feldspar relative to the apparent
lack of muscovite, within the pelitic rocks.
Detailed mapping in the summer of 2013 revealed that the
prospective Janice Lake Formation extends for at least 15 km
northeast of Janice Lake, where it has an apparent thickness of 2
km. The northeast-trending Burbidge Lake shear zone, which has also
been traced 15 km northeast of Janice Lake, causes repetition of
the Janice Lake Formation to the southwest. Extension of the Janice
Lake Formation further to the north than previously appreciated
highlights a prospective area for sediment-hosted Cu mineralization
similar to that found in the Janice and Rafuse lakes areas.
Keywords: Wollaston Domain, Wollaston Supergroup,
Paleoproterozoic, Janice Lake, Burbidge Lake, fanglomerate,
sediment-hosted copper deposits, bedrock mapping.
1. Introduction The Janice Lake project was initiated to augment
previous detailed mapping in the east-central Wollaston Domain by
Delaney (1994 to 1995) and to evaluate the economic potential of
areas along strike of known Cu occurrences (Figure 1). This project
is being conducted in conjunction with a study of the surficial
geology of the area (Hanson, this volume).
http://economy.gov.sk.ca/SOI2013V2_M2.1http://economy.gov.sk.ca/SOI2013V2_M2.2
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Saskatchewan Geological Survey 2 Summary of Investigations 2013,
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Figure 1 – Regional 1:250 000-scale geological map of
east-central Wollaston Domain showing locations of the two detailed
map areas (A and B outlined in black). Inset map shows the region
with respect to domainal subdivisions of the Canadian Shield in
northern Saskatchewan. Informal lake names appear in single
quotations.
Anderson LakeInlier
JohnsonLakeInlier
BurbidgeLake
JaniceLake
JunoLake
‘StolenBoot’Lake
‘RabbitBush’Lake
ThompsonRiver
KarinLakeInlier
FraserLakesInlier
Precambrian Domains
RafuseLake
Wollaston Domain
Wollaston SupergroupArkose/calcareous arkose
Fanglomerate/conglomerate
- - - UNCONFORMITY - - -
Slate, phyllite, mica schist
Pelitic gneiss
- - - UNCONFORMITY - - -
ArcheanFelsic orthogneiss
Mylonitic gneiss
Granite/granodiorite
250 km
Wol
lasto
n
10 km0
A
B
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Saskatchewan Geological Survey 3 Summary of Investigations 2013,
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This work also builds on previous investigations that focussed
on the stratigraphic setting (Coombe, 1994; Delaney, 1993, 1994;
Delaney et al., 1995, 1996, 1997) and on its structural setting
(Tran and Yeo, 1997; Tran et al., 1998: Yeo and Savage, 1999)
within the Paleoproterozoic supracrustal rocks of the Wollaston
Supergroup on the southeastern side of the central Wollaston
Domain. This year’s mapping will be combined with Delaney’s (1994
to 1997) work to create a compilation map for the area extending
from Burbidge to Nelson lakes.
In 2013, an 11-week mapping program was carried out in two
areas; one encompassing the north end of Burbidge Lake and the
other, a region to the northeast of Janice Lake from Juno Lake
almost to the Thompson River (Figures 1 and 2). Much of the map
area northeast of Janice Lake is covered by dense forest; last
having been burned about 30 years ago. Where there is outcrop, it
is commonly covered with thick lichens and/or moss. In contrast, a
majority of the map area centered on Burbidge Lake was burned in
2010. The burn associated with that fire was very spotty, but it
did result in some excellent lichen-free exposures.
2. Previous Work The first published reconnaissance work in the
area was performed by McMurchy (1936) and Rice (1951) of the
Geological Survey of Canada. In 1969, Rath completed an
industry-supported M.Sc. thesis on the petrology and base metal
mineralization in the Janice Lake area. Scott (1973) mapped the
west half of the 74A/15 NTS map sheet, at a scale of 1:63,360 and
made detailed geological maps of the Janice and Rafuse showings.
The base metal potential in the George Hills, Johnson and Kaz
lakes, and Geikie River areas was investigated by Coombe in 1977
(Coombe, 1991). Regional 1:250 000-scale compilation bedrock
geology and metallogenic maps were prepared by Ray (1983) and Scott
(1986), respectively. In 1984, a regional lake sediment and water
geochemical survey was completed by the Geological Survey of Canada
(Geological Survey of Canada,1984; Hornbrook and Friske, 1988).
A series of more detailed mapping projects and investigations of
base metal potential continued from 1994 to 1997 (Delaney 1994;
Delaney et al., 1995, 1996; Tran and Yeo, 1997). A publication
summarizing all the known sediment-hosted base metal deposits of
the Wollaston Domain was released by Coombe (1994).
3. Regional Geological Setting The Burbidge Lake–northern Janice
Lake map area is in the east-central margin of the Wollaston
Domain, which is bounded by the Needle Falls shear zone to the
southeast and by the Wollaston-Mudjatik Transition Zone to the
northwest. The domain consists of a tightly northeast-trending fold
and thrust belt of Paleoproterozoic metasedimentary rocks
containing inliers of Archean granitoid rocks exposed in structural
domes. With respect to the map area, Archean basement rocks are
exposed in the Johnson River inlier to the north, the Anderson Lake
granite to the south, and the Fraser lakes inlier to the west
(Figure 1; Ray, 1983). These inliers are composed of mostly
leucocratic coarse-grained granite with lesser tonalitic felsic
gneisses. The contact between the Archean inliers and
Paleoproterozoic sedimentary rocks is marked by a sharp
structurally modified unconformity.
The Paleoproterozoic metasedimentary rocks, referred to as the
Wollaston Supergroup (Yeo and Delaney, 2007), record deposition of
rift, passive margin, and foreland basin successions, which were
deposited during the opening and closing of the Manikewan Ocean
(Stauffer, 1984). The Burbidge-Janice lakes area is underlain by
rocks stratigraphically situated within the upper sequence of the
Wollaston Supergroup, at the base of the Geikie River Group (Table
1). The Wollaston Domain was intruded by a variety of granitoid
rocks (Harper et al., 2005).
4. Unit Descriptions Table 1 provides a summary of previous
authors’ subdivisions of the rock units within the immediate
mapping area. The stratigraphic nomenclature used by Delaney et al.
(1995) and Yeo and Delaney (2007) was adopted for this study.
a) Daly Lake Group The oldest rocks in the Wollaston Supergroup
exposed in the study area belong the Daly Lake Group. The Daly Lake
Group comprises pelite, psammopelite, psammite, and quartzite,
showing an overall upward increase in compositional maturity (Yeo
and Delaney, 2007). Exposure of the Daly Lake Group is shown
through its member, the Bole Bay Formation, which rests
structurally above the younger Geikie River Group due to thrusting
northwest of Burbidge Lake.
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Saskatchewan Geological Survey 4 Summary of Investigations 2013,
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Figure 2 – Simplified geological maps of the: A) northern Janice
Lake area and B) Burbidge Lake map areas. Informal lake names
appear in single quotations.
Legend
Glacial Drift
Pegmatite
Protomylonite
Arkose and calc-silicate
Arkose and quartz areniteArkoseArkose and wacke
Conglomerate
Calc-silicate brecciaFelsic rockWackeSiltstone and
wackeGranitized siltstone
Quartz arenite and wackeArkose
Polymictic conglomerate
Conglomerate and sandstone
Fanglomerate
Pelite to psammopelite
Psammite to psammopelite
Undivided Intrusive Rocks
--- Intrusive Contact---Paleoproterozoic
Wollaston SupergroupFraser Lakes Formation
Undivided Supracrustals Rocks
Rafuse Lake Formation
Janice Lake Formation
--- Fault Contact ---
Bole Bay Formation
Symbols
Photo lineament
Thrust fault
Trace of F3 axial plane
Northern Janice Lake area (North Sheet)
Burbidge Lake area (South Sheet)
‘RabbitBush’Lake
‘StolenBoot’Lake
Burbidge Lake
0 21 km
0 21 km
N
N
Burbidge Lakeshear zone
Burbidge Lakeshear zone
Burbidge Lake shear zone
West Burbidge thrust fault
A
B
... ...
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Table 1 – Comparison of stratigraphic nomenclature used in the
study area by previous workers. Unit numbers correspond to their
respective maps.
Bole Bay Formation
The type area of the Bole Bay Formation is about 50 km southwest
of Janice Lake where it has a mapped true thickness of 120 m (Tran
et al., 1998). At Burbidge Lake, the formation is characterized by
a succession of cordierite- and sillimanite-bearing psammopelite
and pelite (Figure 3).
Psammite to psammopelite (BBrn) is pink to pinkish grey
weathering and medium grained, with local K-feldspar–rich partial
melt layers. Selective hematization and minor sillimanite nodules
are present. A strong foliation is developed (Figure 3A). The
psammite is generally thickly bedded with mafic mineral content of
less than 5%. In more psammopelitic to pelitic layers,
K-feldspar–rich leucosome lenses containing cordierite and
sillimanite, with biotite selvages comprise up to 10% of the rock.
This unit is only found on the west side of Burbidge Lake. The
contacts within the unit and with BBnp are transitional.
Pelite to psammopelite (BBnp) is grey to pink, fine to medium
grained with distinct pinkish brown-grey irregular bodies of
coarse-grained quartzofeldspathic leucosome (Figure 3B). The rocks
are strongly foliated, locally containing coarse-grained white
plagioclase porphyroblasts up to 4 cm in diameter and sillimanite
nodules up to 5 cm in length (Figure 3C). The leucosome composes up
to 60% of the rock and contains coarse-grained cordierite
Rock Unit This Study
Yeo and Delaney (2007)
Tran (2001)
Tran and Yeo
(1997)Delaney et al. (1995)
Delaney (1994)
Scott (1973)
Marble Hidden Bay Assemblage 28 16/17 15
Arkose and interbedded calc-
silicaterc Fraser Lakes Formation 26/27 15 rc rc 14
Arkose with intercalated
quartz areniterq rq
Arkose and interbedded
wacker2/r3 r2/r3 r2/r1 9
Arkose, psammite,
conglomerate, calc-silicate, and
calc-silicate breccias
Rafuse Lake Formation
Rafuse Lake Formation 13*
Rafuse Lake
Formationrp/cbx/ra/rqv
Fanglomerate and conglomerate with arkose and
minor pelite
Janice Lake Formation
Janice Lake Formation 23/24/25 12
Janice Lake Formation o/p1 11
Quartzite and arkose
Burbidge Lake Formation 21/22 13 6/7
Heterogeneous psammopelite to
psammite
Roper Bay Formation 20 11
Psammopelite to psammite
Thompson Bay Formation 19 10
Cordierite–sillimanite–
K-feldspar pelite to psammopelite
np/rn Bole Bay Formation 15 8/9 np 16
Gei
kie
Riv
er G
roup
Dal
y La
ke G
roup
* noted that it was a younger sequence but could not distinguish
it form the Burgidge Lake Formation.
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Saskatchewan Geological Survey 6 Summary of Investigations 2013,
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Figure 3 – Rocks of the Bole Bay Formation, Burbidge Lake. A)
Interlayered psammite and psammopelite (unit BBrn) with tight
northeast-trending F3 minor fold (station JF13-38-001: UTM 495201 m
E, 6298960 m N); B) pelite and psammopelite (unit BBnp); over 50%
of the outcrop is K-feldspar–rich leucosome containing cordierite
and sillimanite (station JF13-34-001: UTM 495383 m E, 6298369 m N);
C) sillimanite nodules flattened and aligned parallel to S1
(station JF13-38-003: UTM 495623 m E, 6298878 m N); and D)
coarse-grained cordierite within leucosome (station JF13-38-003:
UTM 495623 m E, 6298878 m N). Note: All UTM coordinates are in NAD
83, zone 13V.
(Figure 3D). Up to 2 to 3% magnetite is found locally. This unit
underlies the northwestern side of Burbidge Lake and just east of
‘Rabbit Bush Lake’ 1 just outside the map margins.
b) Geikie River Group The term ‘Geikie River Group’ was proposed
by Yeo and Delaney (2007) for the succession of conglomerate,
arkose, calc-silicate–bearing arkose, calc-silicate rock, and
marble unconformably overlying the Daly Lake Group. The majority of
the two map areas are underlain by the Geikie River Group. Contacts
between formations within the Group are typically transitional.
Deposition of the Geikie River Group has been constrained to 1.88
to 1.86 Ga (Tran, 2001).
Janice Lake Formation
The Janice Lake Formation, the basal unit in the Geikie River
Group, includes fanglomerate and conglomerate with interbedded
arkose (Delaney et al., 1995). It is host to copper occurrences in
the vicinity of Janice Lake. The Janice Lake Formation is found
intermittently in the Wollaston Domain including, from north to
south, the following areas: Duddridge Lake (Delaney, 1993),
Haultain River (Tran et al., 1999), Highrock Lake (Yeo and Savage,
1999), Hills Lake (Delaney et al., 1997), and northeast of
Wollaston Lake (Harper et al., 2005).
1 Informal lake names first appear in single quotations;
subsequently the quotes are dropped.
A B
C D
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Fanglomerate (JLo) is distinctively weathered to a mottled
maroon colour. It is comprised of a poorly sorted framework of
sub-angular to sub-rounded hematitic clasts, ranging from a few
centimetres to meters in diameter, in a fine- to medium-grained
quartzofeldspathic matrix (Figure 4A). At some places, clasts are
no longer distinguishable due to alteration, granoblastic
recrystallization of clasts and matrix, and/or deformation. The
most abundant clasts consist of pebble to boulder-sized, maroon to
buff, hematitic, laminated to massive arkose. Pebble-sized,
sub-rounded, granitic, calc-silicate, amphibolite(?) and quartz
clasts are rare. The ‘exotic’ nature of the granitoid and
amphibolite clasts, and their smaller (2 to 6 cm in diameter) and
better rounded character, suggest a more distal source than the
arkosic clasts. In some outcrops the granitoid and quartz clasts
have a weak internal fabric that is locally sub-parallel to the
main foliation, but often oblique, possibly suggesting they were
derived from a previously deformed terrain.
The fanglomerate has a whitish to grey, fine- to medium-grained
quartzofeldspathic matrix containing up to 10% biotite. Locally,
the epidote and biotite content combined can exceed 15% along with
up to 10% calcite. The relative abundance of clasts to matrix
ranges from less than 20% up to 80%. Tran and Yeo (1997) suggested
the matrix farther south on Burbidge Lake is possibly a
pseudomatrix, comprising largely recrystallized arkosic clasts
‘lost’ in the matrix.
The fanglomerate has been affected by a number of secondary
processes that include late diagenetic alteration, metamorphic
recrystallization, and syn- to post-tectonic development of partial
melt segregations (Delaney et al., 1995). In some areas, these
secondary processes have rendered the clasts unrecognizable.
Therefore, most of the
Figure 4 – Fanglomerate of the Janice Lake Formation. A)
Laminated and homogenous boulder-sized arkose clasts (station
JF13-13-013: UTM 506129 m E, 6310337 m N); B) possible bedding
contact (dashed line) distinguished by a change in clast size
across middle of photograph (station JF13-13-013: UTM 506129 m E,
6310337 m N); C) flattened arkose clasts aligned parallel to
regional S3 foliation with laminated arkose clasts perpendicular to
it (station JF13-25-009: UTM 508498 m E, 6308803 m N); and D)
strongly foliated fanglomerate (station JF13-30-006: UTM 510450 m
E, 6311002 m N).
A B
C D
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Saskatchewan Geological Survey 8 Summary of Investigations 2013,
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Figure 5 – Quartz-pebble conglomerate of the Rafuse Lake
Formation, Burbidge Lake (station JF13-39-005: UTM 497515 m E,
6298445 m N).
fanglomerate appears to be matrix supported. Partial melting
appears to have been selectively concentrated along clast
boundaries and along crude bedding planes.
On an outcrop scale, the fanglomerate appears to exhibit crude
beds of variable, metre-scale thickness depicted by the size and
abundance of the arkose clasts (Figure 4B). Crude clast-supported
beds of variable thickness with sorted, sub-rounded clasts ranging
from 2 to 4 cm in diameter are interbedded with layers that contain
angular to sub-angular, meter-sized clasts. These bedding contacts
are generally sharp.
The fanglomerate is variably deformed (Figure 4C). In places,
clasts are moderately to strongly elongated, and elsewhere there is
a weak to locally very strong foliation defined by the degree of
flattening of the clasts (Figure 4D). Many of the observed outcrops
exhibited a high degree of deformation with only selective areas
containing a weak to moderate foliation and lineation.
The fanglomerate unit is extensive throughout both the map areas
(Figure 2). The contact between the fanglomerate of the Janice Lake
Formation and the overlying Rafuse Lake Formation is sharp
northwest of the Burbidge Lake shear zone (Delaney et al., 1995),
whereas to the southeast, the fanglomerate is intercalated with
siltstone and sandstone of the Rafuse Lake Formation in a narrow
transitional zone.
Conglomerate and sandstone (JLro) is a sandstone-dominated
succession of fine-grained, laminated rocks, locally characterized
by hematite- and epidote-rich beds (JLro2). Clast-supported
conglomerate beds less than 1 m thick were only found at one
outcrop and are characterized by hematized arkose pebbles set
within a fine-grained, quartzofeldspathic matrix. Very high
magnetic susceptibility readings of 15 to 30*10-3 SI distinguish a
mappable subunit, JLrom, which otherwise displays similar
properties to JLro. This subunit was observed east of ‘Stolen Boot
Lake’ (Figure 2).
Polymictic conglomerate (JLo2) is characterized by a light to
medium grey, quartzofeldspathic matrix containing rounded to
sub-rounded pebbles and cobbles of arkose, wacke, granitoid and
vein quartz. Possible sandstone beds 1 to 2 m wide were observed at
one locality within the unit just north of Burbidge Lake. The
polymictic conglomerate is believed to be a facies equivalent of
the fanglomerate.
Magnetite-bearing polymictic conglomerate (JLom) is
distinguished from the other two conglomerate units on the basis of
its anomalous magnetic susceptibility readings of 15 to 40*10-3 SI.
The conglomerate has a similar clast composition and size range as
JLo2 and appears to be matrix supported. The matrix typically
contains between 5 to 10% mafic minerals dominated by biotite and
hornblende.
Rafuse Lake Formation
The Rafuse Lake Formation is a heterogeneous succession of
arkose, wacke, conglomerate, and calc-silicate breccia (Delaney et
al., 1995), and hosts several copper occurrences in the Janice Lake
area. The contact between the Rafuse Lake and Janice Lake
formations is sharp. Relative stratigraphic positions within the
Rafuse Lake Formation are uncertain.
Conglomerate (RLo) is a light grey to buff weathered unit
locally with maroon mottling. It is characterized by an intact to
disrupted framework of sub-rounded to rounded, pebble to
cobble-sized, commonly elliptical clasts of quartzite and minor
arkose (Figure 5). A minimum apparent thickness of about 50 m is
implied at one location although most of the unit cannot be defined
at the present scale of mapping. The matrix, which appears to have
recrystallized, is composed of plagioclase-quartz-biotite.
Typically the long axes of the elliptical quartzite clasts are
aligned parallel to the main foliation and define a strong
lineation.
The arkose (RLa) unit comprises a pink-buff to grey-weathered,
fine-grained, thin- to medium-bedded succession. Local partial melt
lenses comprise medium- to coarse-grained quartz, magnetite, and
hornblende within fine-grained plagioclase. The unit is moderately
to well foliated. Rath and Morton (1969) reported staurolite in an
arkose unit east of Juno Lake, which is believed to be correlative
to this unit.
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Quartz arenite and wacke (RLqw) is buff to grey weathered and
fine to medium grained. A strong foliation is defined by aligned
biotite and amphibole, which together comprise up to 20% of typical
rocks. Local leucosome blebs and segregations of amphibole and
quartz occur in many of the outcrops. This unit is found on at the
north end of Burbidge Lake (Figure 2B).
Siltstone and wacke (RLsw) is light to dark greyish brown on
weathered surfaces, very fine to fine grained, and strongly
foliated. The unit varies from homogenous siltstone to interbedded
wacke laminae to beds containing up to 20% biotite. Quartz blebs
and stringers also occur locally, and epidote is common as coatings
on fractures and in clots. North of Janice Lake (Figure 2A), wacke,
which is the main rock type in this unit, contains 20 to 25%
biotite throughout, whereas east of Burbidge Lake (Figure 2B),
siltstone with less than 10% biotite is the main rock type. A light
grey weathered, fine-grained, quartzofeldspathic siltstone (RLswg)
occurs locally in this unit east of Burbidge Lake. It is primarily
composed of quartz and feldspar with minor biotite and is variably
assimilated by fine-grained leucocratic granitoid partial melt.
This unit is believed to be the distal lateral facies equivalent of
RLsw, found only on the west side of the Burbidge Lake shear
zone.
Wacke (RLw) is grey to greenish grey weathered, fine to very
fine grained, and massive to well foliated. It is composed of
plagioclase, quartz, biotite (10 to 20%), and epidote (5 to 10%).
Disseminated magnetite is common; hornblende and actinolite are
minor constituents. Leucosomal pegmatite and granite are common as
irregular bodies and dykes within the unit. This is a recessive
unit with very few outcrops observed north of Janice Lake.
Calc-silicate breccia (RLcbx) is a mottled greenish to light
grey–weathered unit that contains subangular to subrounded
fragments of fine-grained plagioclasite in a fine- to
medium-grained matrix of actinolite and plagioclase that locally
contains disseminated and patchy concentrations of medium- to
coarse-grained actinolite and diopside. This unit occurs as 10 to
20 m thick lenses throughout the Rafuse Lake Formation.
A narrow unit of pink- to buff-weathered, fine- to very fine
grained felsic rock (RLfel) was observed in a small area north of
Burbidge Lake. Typical rocks are homogenous, massive and
featureless with a mafic content of less than 5%.
c) Supracrustal Rocks This theorized younger succession of
arkose, wacke, and arenite in the western part of the Janice Lake
area, has not been previously assigned to a specific formation (see
discussion below).
Arkose and interbedded wacke (r2) is pink to grey weathered,
fine grained, and is thin to medium bedded with hematitic laminae
and minor 1 to 2 cm thick layers of brownish grey wacke. It locally
contains rare clots and lenses of actinolite and plagioclase. The
unit contains up to 10% mafic minerals, mostly biotite and
amphiboles. Light green epidote locally coats late fractures.
Millimetre- to centimetre-scale, white partial melts and
calc-silicate pods are also locally found.
Arkose (r3) is buff to greyish pink weathering, medium to thick
bedded, fine to very fine grained, and granoblastic. The mafic
minerals include less than 5% biotite and minor hornblende.
Parallel to sub-parallel quartz-feldspar-hornblende veins and clots
2 cm wide obliquely crosscut the S3 foliation in the arkose. This
unit is believed to be a lateral equivalent of r2 (Delaney et al.,
1995). It also appears similar to RLa; however, it occupies a
higher stratigraphic position (see discussions below). It is
distinguished from the unit RLqw by its lower mafic content and
high (over 25%) K-feldspar content.
Arkose with intercalated quartz arenite (rq) is only found on
the northwest side of Burbidge Lake in association with the West
Burbidge Lake thrust. It weathers light grey to buff and, in some
areas that are more arkose dominant, brown to grey. It is very fine
to fine grained and thinly to thickly bedded. The unit is weakly to
strongly foliated and moderately to strongly lineated.
Fraser Lakes Formation
The Fraser Lakes Formation is a succession of
calc-silicate–bearing arkose with intercalated calc-silicate–rich
beds (Figure 6). The type area for this formation is at Fraser
Lakes, 8 km northwest of the map area, where it has an apparent
thickness of about 850 m (Delaney et al., 1996).
Arkose with intercalated calc-silicate (FLrc) is a light grey to
pinkish white to green, bedded to laminated sequence that also
contains minor wacke. Calc-silicate–rich beds range from 8 to 10 cm
thick on Burbidge Lake to meters thick east of Rabbit Bush Lake.
Distinctive differential weathering and pitting is typical of the
calc-
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Figure 6 – Fraser Lakes Formation. A) Typical differential
weathering of intercalated calc-silicate and arkose (station
JF13-38-007: UTM 496298 m E, 6298813 m N) and B) calc-silicate–rich
layer within the Fraser Lakes Formation, Burbidge Lake (station
JF13-18-005: UTM 506400 m E, 6311330 m N).
silicate–rich layers, which are composed of fine- to
medium-grained plagioclase and quartz (up to 30%), medium- to
coarse-grained actinolite (10 to 15%), and up to 20% combined
diopside, epidote, and calcite. Amphibole and pyroxene, associated
with quartz, are commonly concentrated along late fractures as pods
and blebs, orientated both randomly and parallel to the S3
foliation. The arkose component is laminated to thinly bedded and
contains less than 5% biotite. The foliation is weak to well
developed and the rocks along the northwest side of Burbidge Lake
are strongly lineated. The contacts within this unit appear to be
gradational. This unit also appears to interfinger with many of the
units.
Younger Intrusive Rocks
Several generations of granitic pegmatites of slightly varying
compositions are common throughout both map areas. The granitic
pegmatite dykes include generations that are: folded by F3 folds,
aligned parallel to S3, and are sub-parallel to parallel to late D5
brittle faults. Varieties of the granitic pegmatites include those
that are: 1) actinolite bearing; 2) magnetite bearing with thorium
and uranium enrichment; 3) plagioclase rich with only minor
potassium feldspar; and 4) muscovite and tourmaline bearing. The
magnetite thorium- and uranium-rich pegmatitic dykes are commonly
less than a meter thick, and generally less than half a meter
thick. The average concentrations of U, Th, and K were based on
two-minute analyses using a hand-held gamma and neutron radiation
spectrometer (Radiation Solutions GR-135). The results are only
averages and multiple readings at the same locality slightly vary.
Therefore, they should not be taken as substitutes for direct rock
assays. The highest thorium count was 166.6 ppm (station
JF13-21-005: UTM 509474 m E, 6315476 m N; 5.7 ppm U; total
count=1200) from just northwest of Stolen Boot Lake; whereas the
highest uranium count was 199.4 ppm (station JF13-26-004: UTM
511690 m E, 6313936 m N; 66.8 ppm Th; total count=3300) from
northeast of Stolen Boot Lake.
5. Structural Geology Variable degrees of deformation have led
to some difficulty in correlating structures and related
deformational episodes between different areas within the Wollaston
Domain (Table 2). Based on the present study, the rocks have been
affected by four major deformational events and late brittle
faulting, all of which are attributed to the ca. 1.84 to 1.77 Ga
Trans-Hudson orogeny.
D1 was responsible for the development of a foliation (S1) of
variable intensity. Compositional layering has mostly been
transposed by S1 to produce the main regional S0/S1 composite
foliation. It is most apparent within the interbedded sequences of
arkose and wacke (mainly unit r2 and rq). This first deformation
event has been identified throughout much of the Wollaston Domain,
and was previously attributed to thermal reworking of the basement
and the emplacement of gneiss domes to levels near the
basement/cover contact (Lewry and Sibbald, 1980). In contrast, Tran
and Yeo (1997) suggested that D1 may have been produced by tectonic
transport and crustal imbrication, resulting in moderate crustal
thickening.
D2 is represented by tight to isoclinal folding of the S0/S1
fabric. F2 folds are recumbent, reflecting subhorizontal
shortening, and are thought to be related to northwest-southeast
convergence due to collision of major tectonic
A B
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Figure 7 – Equal-area stereonet plot of minor, doubly plunging,
F3, folds within the Bole Bay Formation, northwest of Burbidge Lake
(n=13).
Table 2 – Comparison of deformation events documented by
previous workers.
blocks (Tran and Yeo, 1997). Evidence of D2 is only seen locally
in the Wollaston Domain and is often combined with D1, however is
it probably both intense and regional extensive but often
overprinted by the D3 deformation (see discussion below).
D3, which produced the northeast-trending structural fabric
typical of the Wollaston Domain, formed by tight to isoclinal,
doubly plunging, southeast-vergent F3 folds, generally with
steeply, northwest dipping axial planes. In the Janice Lake area,
L3 fabrics are best defined by elongated sillimanite nodules
(Figure 3C), and tight folds (F3) are best developed within the
pelites and psammopelites of the Bole Bay Formation (Figure 7). The
fold geometry varies from Class 2 to Class 3 (Ramsay, 1967), but is
more commonly Class 2, with relatively thin fold limbs and
thickened hinges.
Late D3 Reverse Faulting
The study area is cut by two main
northeast-trending–,ductile-brittle, steeply to moderately
northwest-dipping reverse faults: the West Burbidge Lake thrust
fault and the Burbidge Lake shear zone.
The West Burbidge Lake thrust fault is a northeast-trending,
ductile-brittle fault (Tran and Yeo, 1997) that runs through the
western part of Burbidge Lake. Numerous outcrop-scale,
brittle-ductile, reverse faults with extensive gently to moderately
plunging tectonic stretching lineations are associated with this
fault zone (Figure 8). The West Burbidge Lake thrust fault has
thrust predominantly pelitic rocks of the older Bole Bay Formation
over arkoses of the much younger undivided sedimentary succession
that overlies the Rafuse Lake formation. On the basis of the
difference in metamorphic grade between the Bole Bay Formation and
the sedimentary units, the vertical displacement maybe up to
several kilometres.
The Burbidge Lake shear zone is a northeast-trending,
brittle-ductile fault zone (Delaney et al., 1995) that is marked by
a linear topographic low running through the northeastern arm of
Burbidge Lake, the eastern arms of Janice Lake, and to the
northeast within the
Event Major Structural FeaturesThis
StudyTran
(2001)
Tran and Yeo (1997)
Delaney et al. (1995)
Delaney (1994)
Lewry and
Sibbald (1980)
Ray (1975)
Scott (1973)
D5 Brittle faults trending west-northwest D5 D5 D4 D5 D5
D4 Open upright northwest-trending folds and crenulations D4 D4
D3 D4 D4 D3
D3
Tight to isoclinal, northeast-trending doubly plunging folds
(F3); regional pervasive steeply dipping axial planar folation
(S3)
D3 D3 D2 D3 D3 D3 D2 D2
D2
Weak steeply dipping to subvertical axial planar foliation (S2)
tight to isoclinal folding (F2)
D2 D2 D2
D1
Regional axial planar foliation transposed on S0, rare rootless
isoclinal folds, tectonic transport and crustal imbrication
D1 D1 D1 D1 D1 D1
D1 D1
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Figure 8 – Equal area stereonet plot of tectonic stretching
lineations and the fault plane associated with the West Burbidge
Lake thrust (n=11; mean trend=235°; mean plunge=28°).
Figure 9 – Equal area stereonet plot of tectonic stretching
lineation and fault plane associated with the Burbidge Lake shear
zone (n=19; mean trend=291°; mean plunge=67°; part of data set is
taken from Delaney et al. (1995)).
Figure 10 – Tourmaline-bearing pegmatitic quartz veins possibly
aligned parallel to the F4 axial plane (station JF13-38-012: UTM
495496 m E, 6299069 m N).
northern mapping area along several other unnamed lakes (Figure
2A). The fault zone is poorly exposed as it is largely in
topographic lows that are in part occupied by lakes. The Burbidge
Lake shear zone, which is several tens of meters wide, is
characterized by protomylonitic to minor mylonitic rocks. Local
sigmoidal tension gashes and small-scale asymmetric folds noted by
Ramsay and Graham (1970) indicate a dextral shear sense. A
pervasive, steeply west-northwest–plunging tectonic stretching
lineation is common (Figure 9; Delaney et al., 1995). Thus, at
least two generations of movement have occurred; however, the
timing of these events is unclear. The Burbidge Lake shear zone
repeats the Janice Lake Formation to the southeast of it, and
therefore vertical displacement is
believed to be constrained to the thickness of the Janice Lake
Formation. The Burbidge Lake shear zone was traced throughout the
northern map area and likely continues farther to the northeast. An
increase in the abundance of sandstone and more mature
conglomerates (unit JLro) east of the Burbidge Lake shear zone, may
represent a more distal sequence of the Janice Lake Formation
(Delaney et al., 1995).
D4 was relatively weak in the study area and had little effect
on the northeast-trending regional fabric. This event involved
northwest-trending, upright folding, and is expressed as a weak
crenulation on F3, possibly seen within an antiformal F3 map-scale
fold just north of Burbidge Lake (Figure 2B). No axial planar
cleavage (S4) was found in the map area, nor across the eastern
Wollaston Domain (Tran, 2001). However, F4 axial planes were
suggested by Tran (2001) to be filled with late, tourmaline-bearing
pegmatitic quartz veins. Possibly one of these veins was found
north of Burbidge Lake (Figure 10). This deformation probably
occurred during a period of regional cooling, and was accompanied
by minor retrogression and alteration (Tran and Yeo, 1997).
D5 produced a widespread conjugate set of northeast- to
northwest-trending brittle faults that crosscut all of the
structures described above. These structures are defined by
lineaments that correspond to topographic depressions. This
faulting is associated with, and possibly forms part of, the
regionally extensive Tabbernor fault system in northern
Saskatchewan. Kinematic indicators along the faults predominantly
show sinistral movement (Figure 11A); however,
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Figure 11- Minor faults related to D5 deformation. A) Pegmatite
dyke aligned 010°; fanglomerate of the Janice Lake Formation,
showing sinistral movement (station JF-18-004: UTM 506773 m E,
6311115 m N); B) a set of minor dextral faults aligned 009° showing
offset of pink pegmatite dykes (station JF13-27-010: UTM 511502 m
E; 6311096 m N); and C) a set of minor faults showing dextral
movement within unit JLro (station JF13-19-008: UTM 510107 m E,
6310055 m N).
dextral movement along micro-faults was also observed (Figures
11B and 11C). D5 may be related to the disruption of the accreted
terrain collage of the Reindeer Zone during terminal
post-collisional stages of deformation (Tran and Yeo, 1997).
6. Metamorphism With the exception of some late pegmatitic
dykes, most units were regionally metamorphosed during two
Hudsonian metamorphic events, M1 and M2. Textural relationships
between the similar metamorphic mineral assemblages suggest M1
(1860(?) to 1816 Ma) began before the peak of D1 deformation and
ended during D2 deformation and M2 (1816 to post-1800 Ma) was
broadly coeval with, and outlasted, D3 deformation (Tran, 2001).
The map areas are underlain by a wide variety of quartzofeldspathic
sedimentary rocks, which are not good record keepers of metamorphic
processes. Therefore, most previous metamorphic studies have
focussed on pelitic rocks, as these rocks respond relatively well
to changes in pressure and temperature and therefore are better
suited record the metamorphic history.
The Janice Lake and Rafuse Lake formations, in the area north of
Janice Lake, were metamorphosed to lower amphibolite facies during
M1. The presence of staurolite, garnet, biotite, hornblende, and
andesine-oligoclase in the various units around Janice Lake caused
Rath (1969) and Scott (1973) to suggest low-pressure
intermediate-grade metamorphic conditions. Local partial melts are
found within the arkoses and fanglomerate of the Janice Lake
Formation possibly associated with M2 suggesting middle to upper
amphibolite facies.
A B
C
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At Burbidge Lake, metamorphic grade reached upper-amphibolite
facies as indicated by the stability of sillimanite, cordierite,
and K-feldspar with the apparent absence of muscovite along with
partial melts within the pelitic rocks. Differing mineral
orientations indicate that two distinct generations of sillimanite,
cordierite, and K-feldspar developed during the M1 and M2 events.
Cordierite partially or fully replaced sillimanite at some
localities. K-feldspar–rich magmatic leucosome generally contains
coarse-grained cordierite associated with M2.
7. Exploration History The exploration history of the area was
compiled from the Saskatchewan Mineral Deposit Index (SMDI) where
more detailed information can be found in regards to the copper
showings. Other information can be found within assessment reports,
which can be assessed through the Saskatchewan Geological Survey
website. The first reported discovery of base metals in the
Wollaston Domain was in 1953, by Simon Eninew who, while
prospecting for E.F. Partridge, discovered a malachite-stained,
chalcocite-bearing boulder just northeast of Janice Lake along the
Wathaman River. It was not until 1966 that Great Plains Development
found copper mineralization in place around Janice Lake. From 1962
to 1978, various companies including E.F. Partridge, Falconbridge
Mines, Great Plains Development Co. of Canada Ltd., Newmont Mining
Corp. of Canada Ltd., Wollex Exploration Ltd., and Giant
Yellowknife Mines discovered several boulder trains and showings,
mostly in an isolated area around Janice Lake including: Janice
Lake (1966; SMDI #1016), Janice Lake North (1966; SMDI #1016), Kaz
(1966; SMDI #1017), Zap Lake (1966; SMDI #1020), East Burbidge
(1967; SMDI #996), “A” Lake (1968; SMDI #1021), Rafuse (1969; SMDI
#1018), Lily (1969; SMDI #997), Howe Lake (1973; SMDI #1022), Kwest
(1974; SMDI #1022), Breezy (1974; SMDI #1019a), and Zed Lake (1976;
SMDI #998) showings. From 1991 to 1997, Noranda Exploration and
Mining Ltd. carried out several geophysical, prospecting and
drilling programs that resulted in the discovery of a number of
additional copper occurrences both in boulders and outcrop
including: the JS (SMDI #2632), JS2 to 4 (SMDI #996), RS1 to RS3
(SMDI #998), Genie (SMDI #2664), and Sunshine (SMDI #2665)showings.
In 1994, Gary Delaney, with the Saskatchewan Geological Survey
discovered the Jansem 1 and 2showings (SMDI #2632), while
undertaking geological mapping in the Janice Lake area. From 2002
to 2007, Phelps Dodge Corp. of Canada discovered four additional
copper showings: JL-2 (SMDI #996), Mackenzie(SMDI #2665), JL-1
(SMDI #996), and Roberts (SMDI #2665). In 2008, work was conducted
by Resource EyeServices Inc. on behalf of Uracan Resources and
Bonaventure Enterprise, targeting uranium in granitic intrusionsand
pegmatite. In 2012, Transition Metals staked a group of
dispositions in the Janice Lake area to further evaluate the area’s
copper potential.
To the south of Janice Lake and to the east of Rafuse Lake a
total of seven boulder showings and 22 bedrock showings have
currently been discovered. These showings all occur in the area
mapped by Delaney et al. (1995).
Although many of the copper showings in the Janice Lake area
were visited during the current field program no new showings were
noted within the areas mapped in the summer of 2013.
8. Economic Geology The Wollaston Domain has long been known to
host copper mineralization (Rath, 1969; Scott, 1973; Coombe, 1977,
1994; Potter, 1977, 1978, 1980; Coombe Geoconsultants Ltd., 1991;
Delaney 1993, 1994; Fossenier et al., 1994; Fossenier, 1995; Purser
and Delaney, 1994; Delaney et al., 1995, 1996, 1997; Tran and Yeo,
1997; Delaney and Savage, 1998; Beaudmont, 2003; Yeo and Delaney,
2007). Historically, the origins of these copper occurrences have
been variously interpreted as being of syngenetic (Rath and Morton,
1969), hydrothermal (Scott, 1973), or diagenetic origin (Coombe,
1994). The currently accepted model is that the copper occurrences
are sediment-hosted stratiform copper deposits (Delaney, 1994;
Delaney et al., 1995; Delaney and Savage, 1998).
For sediment-hosted stratiform copper deposits, the mineralizing
process typically involves movement of oxidized, copper-bearing
fluids through permeable strata, until they encounter a structural
trap and/or reducing zone/horizon (Hitzman et al., 2005). For many
model deposits, metal sources are believed to be red-bed
sedimentary rocks (ibid.), therefore suggesting the arkoses of the
Burbidge Lake Formation, from which the fanglomerates are derived
and/or the fanglomerates themselves are the possible metal
sources.
Basin geometry and basin evolution probably played a major role
in the distribution of the Janice Lake copper occurrences, of which
more than 20 are hosted either in fanglomerate of the Janice Lake
Formation or in the overlying Rafuse Lake Formation. Many of the
copper occurrences appear to be at or near the contact between the
Rafuse Lake and Janice Lake formations, which may be have acted as
a reducing horizon. The showings along this contact occur as
irregular, patchy concentrations or stratiform occurrences (Delaney
and Savage, 1998). Copper mineralization within the Janice Lake
fanglomerate, including Jansem 1 and 2 and JL 1 and 3, appears to
lack the presence of any noticeable reductive horizons, however,
reduced zones within the fanglomerate area displayed by the lack of
hematization around the Jansem 2 showing.
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Economic minerals in the Janice Lake area include copper,
chalcocite, malachite, azurite, antlerite, bornite, chalcopyrite,
and bornite, occurring as clots and disseminations along fractures
and as coatings on weathered surfaces (Coombe, 1994; Delaney et
al., 1995; McGowan et al., 1997). The mineralized zones, and the
immediately associated rocks, are weakly magnetic. Chlorite appears
to be slightly more abundant in and near the mineralized zones.
Sediment-hosted stratiform copper deposits are common around the
world, but economically significant deposits are rare (Hitzman et
al., 2005). The abundance of small, and in some cases high-grade,
showings in the Janice Lake area suggests favourable conditions for
the formation of these types of deposits, particularly in the
Janice Lake and Rafuse Lake formations. As mapping this past summer
has traced these favourable units 15 km to the northeast, that area
should also be evaluated for its potential to contain additional
occurrences of sediment-hosted stratiform copper
mineralization.
9. Discussion and Conclusions
a) Depositional Environment U-Pb data from detrital zircon
collected throughout the Wollaston Supergroup indicate a
depositional age for the sequence ranging from 2.07 to 1.86 Ga
(Tran et al., 2008). A U-Pb age of 2075 ±2 Ma from detrital zircon
in the Courtney Lake Group provides the maximum age for the onset
of Wollaston Supergroup sedimentation (Yeo and Delaney, 2007), and
deposition is thought to have ceased with emplacement of the 1.87
to 1.86 Ga Wathaman Batholith (Tran et al., 2008). Field
relationships observed by Tran et al. (1998), Tran ( 2001), and
Delaney et al. (1995) suggest that the upper Wollaston Supergroup
was deposited in an active tectonic setting, when the southern
Hearne craton margin was evolving from a back-arc basin to a
foreland basin. The Daly Lake and Geikie River groups within the
map area were deposited in the foreland-basin stage. Therefore, the
formations within the map area have been interpreted to be
deposited in fluvial-alluvial, and restricted marine to lacustrine
environments (Tran, 2001).
Within the fanglomerate, there is a predominance of arkosic
clasts and arkosic matrix; detritus of which was possibly derived
from the underlying Burbidge Lake Formation, which consists of
arkoses and quartzites. Thus, the presence of the fanglomerate
suggests the existence of an actively uplifting paleoenvironment.
Yeo and Delaney (2007) attributed the inferred uplift to
imbrication caused by craton-verging thrust faults resulting from
an advancing tectonic load.
A contrasting view is that of Beaudemont (2003), who suggested
that the fanglomerate is composed of in situ breccias and
pseudo-fanglomerates that formed as a result of felsic metasomatism
during tectonism. Beaudemont’s arguments supporting a
non-sedimentary origin include: 1) the presence of fine-grained
cobbles within fragments; 2) the difficulty in distinguishing
matrix and fragments within the same bed; 3) the homogenous
composition of the fragments; and 4) the unusually large thickness
of the fanglomerate/debris flow given its highly deformed nature.
Based on the current mapping, however, it is suggested that the
fanglomerate has undergone later deformation, which could have
caused brecciation and reworking of the fanglomerate. It is
believed that many local thrust faults could have caused reworking
of the fanglomerate, particularly during late D3 when the Burbidge
Lake shear zone developed. Within the fanglomerate there are rare
pebble- to cobble-sized, sub-rounded, granitic, calc-silicate,
amphibolite(?) and quartz clasts in some outcrops, which also
supports a sedimentary origin for this unit.
The quartz pebble conglomerates (RLo) found just north of
Burbidge Lake could also be derived from the Burbidge Lake
quartzite (Figure 5) and have been previously interpreted as
channel deposits related to deltaic sedimentation (Tran and Yeo,
1997).
Coarse siliciclastic sediments, including fanglomerate,
conglomerate, and associated units within the Janice Lake Formation
are found intermittently in the throughout eastern part of the
Wollaston Domain, with the most extensive occurrence in the Janice
and Burbidge lakes areas. A fold closure of a correlative unit to
the fanglomerate is shown by Tran and Yeo (1997) southeast of
Burbidge Lake and currently marks its southern extent; a lateral
facies change west of Nelson Lake marks its northern extent.
Therefore, fanglomerate and associated conglomerates have a minimum
strike length of 35 km with a local apparent thickness of generally
between 1.4 and 2 km, however, the true thickness is probably less
as it is probably structurally repeated by folding and a series of
northeast-trending thrust faults. The Burbidge Lake shear zone was
traced throughout the northern map area and likely continues
farther northeast.
The mapped sedimentary rocks containing units r2, r3, and rq
along the western margin of the Janice Lake area appears to be in a
stratigraphically higher position than the arkoses and arenites of
the Rafuse Lake Formation; however, they are compositionally quite
similar. It is presently unclear whether these units are
stratigraphically distinct from the Rafuse Lake Formation or thrust
slices.
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Saskatchewan Geological Survey 16 Summary of Investigations
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b) Structure Many of the previous exploration companies have
noted a high degree of difficulty when attempting to correlate
drill holes due to both facies changes in the sedimentary
succession and the effects of deformation. Polyphase folding and
faulting are believed to be the main factors responsible for the
lack of continuity of the mineralization. Across the map area, the
fanglomerate displays a wide variation in clast size, clast shape,
clast to matrix ratios, and matrix composition. These variations
could be attributed to lateral facies changes because within an
alluvial fan model, compositional variations are expected; however,
differential strain also explains some of the observed variation
particularly that resulting from the pervasive F3 and S3 fabrics.
Due to the style of F3 folding, the fold hinges remain relatively
‘low’ strain, whereas the limbs are thinned, causing clasts to be
stretched and elongated. Along the fold limbs, previous S1/S2
foliations are re-aligned sub-parallel to parallel to S3 so that
they are commonly indistinguishable on most outcrops. The limbs of
the F3 folds are also common activation sites for local
transcurrent and thrust zones. In suspected fold hinges, the strain
is low and primary features such as crossbedding have been observed
by previous authors (Scott, 1973; Delaney, 1994; Delaney et al.,
1995; Tran and Yeo, 1997). Large, angular to sub-angular,
boulder-size clasts are also visible in suspected fold hinges, some
with internal laminations that appear to be randomly orientated
(Figure 4C). However, in some outcrops, the internal laminations
within the boulder-sized clasts could be aligned parallel to the F2
foliation.
Although on a broad scale the stratigraphy and structural
framework has been established for the sedimentary successions,
many details about both remain unresolved. The context of known
mineral occurrences and their relation to basin structure and
deformation history is still poorly understood. This information is
needed to evaluate the present copper showings and the potential of
the Wollaston supracrustal succession to host other mineral
occurrences.
10. Future Work This year’s mapping will be combined with
Delaney’s (1994 to 1998) work in the region to create a compilation
map for the area extending from Burbidge Lake to Nelson Lake. The
recent burn in Burbidge Lake area affords a perfect opportunity to
extend detailed mapping to the south to find the southern extent of
the Janice Lake Formation. To complement the mapping projects, a
geochemical study would be beneficial, especially within the
fanglomerate to determine whether the ore-forming processes have
left a geochemical fingerprint. A B.Sc. thesis by E. Martyniuk of
the University of Saskatchewan is being undertaken to characterize
the petrography of the ore minerals and the chemical
characteristics of the Jansem 1 and 2 showings.
11. Acknowledgements Field work was performed with the valuable
assistance of Kate Houston, Evan Martyniuk, Billy Fan, Adam
Edwards, Ravyn Godwin, and Jennifer Regier. Much gratitude is given
to Michelle Hanson and the bedrock mapping geologists of the
Saskatchewan Geological Survey for their patience and guidance.
Field visits by Gary Delaney and Jason Berenyi were very helpful in
improving the map and report. I would also like to thank Hal
Sanders for an enjoyable field visit. Logistical support was
provided by Osprey Wings and Thompson Camps in Missinipe,
Saskatchewan.
12. References Beaudmont, D. (2003): Sediment-hosted Cu-Ag
mineralization, Janice Lake, Wollaston Domain; rep. prepared
for
Phelps Dodge Corp., Sask. Ministry of the Economy, Sask.
Geological Survey, Assessment Report 74A15-SW-0036, 14p.
Coombe, W. (1977): La Ronge–Wollaston belts base metals project:
George, Hills, Johnson, and Kaz lakes and Geikie River areas; in
Summary of Investigations 1997 by the Saskatchewan Geological
Survey, Sask. Dep. Miner. Resour., p85-104.
__________ (1994): Sediment-hosted Base Metal Deposits of the
Wollaston Domain, Northern Saskatchewan; Sask. Energy Mines, Rep.
213, 108p.
Coombe Geoconsultants Ltd. (1991): Base metals in Saskatchewan;
Sask. Energy Mines, Open File Rep. 91-1, 218p.
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Saskatchewan Geological Survey 17 Summary of Investigations
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Delaney, G.D. (1993): A re-examination of the context of U-Cu,
Cu, and U mineralization, Duddridge Lake, Wollaston Domain; in
Summary of Investigations 1993, Saskatchewan Geological Survey,
Sask. Energy Mines, Misc. Rep. 93-4, p73-85.
__________ (1994): Geological setting of sediment-hosted copper
mineralization in the area southwest of Janice Lake, Wollaston
Domain; in Summary of investigations 1994, Saskatchewan Geological
Survey, Sask. Energy Mines, Misc. Rep. 94-4, p53-62.
Delaney, G.D., Jankovic, Z., MacNeil, A., McGowan, J., and
Tisdale, D. (1997): Geological investigations of the
Courtenay-Cairns Lake Fold Belt and the Hills Lake Embayment,
Johnson River Inlier, Wollaston Domain, northern Saskatchewan; in
Summary of Investigations 1997, Saskatchewan Geological Survey,
Sask. Energy Mines, Misc. Rep. 97-4, p90-101.
Delaney, G.D., Maxeiner, R.O., Rawsthorne, M.L., Reid, J.,
Hartlaub, R., and Schwann, P. (1995): Geological setting of
sediment-hosted copper mineralization in the Janice Lake area,
Wollaston Domain; in Summary of Investigations 1995, Saskatchewan
Geological Survey, Sask. Energy Mines, Misc. Rep. 95-4, p30-48.
Delaney, G.D. and Savage, D. (1998): Geological investigations
of the context of quartzite-hosted Zn-Pb mineralization, Sito-Adams
lakes area, Wollaston Domain (parts of NTS 74A-4 and -5); in
Summary of Investigations 1998, Saskatchewan Geological Survey,
Sask. Energy Mines, Misc. Rep. 98-4, p29-35.
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