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> Forside > Publikationer > Geology of Greenland Survey Bulletin > Vol. 191 Geol. Greenl. Surv. Bull. > Review of Greenland Activities 2001, pp 133-143

GEOLOGY OF GREENLAND SURVEY BULLETIN 191

 
Qaanaaq 2001: mineral exploration reconnaissance in North-West Greenland

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background image
Project Qaanaaq 2001, involving one season's field
work, was set up to investigate the mineral occurrences
and potential of North-West Greenland between Olrik
Fjord and Kap Alexander (77°10´N ­ 78°10´N; Fig. 1).
Organised by the Geological Survey of Denmark and
Greenland (GEUS) and the Bureau of Minerals and
Petroleum (BMP), Government of Greenland, the project
is mainly funded by the latter and has the overall goal
of attracting the interest of the mining industry to the
region.
The investigated region ­ herein referred to as the
Qaanaaq region ­ comprises 4300 km
2
of ice-free land
centred on Qaanaaq, the administrative capital of Qaa-
naap (Thule) municipality. Much of the region is char-
acterised by a 500­800 m high plateau capped by local
ice caps and intersected by fjords and glaciers. High
dissected terrain occurs in Northumberland Ø and in the
hinterland of Prudhoe Land where nunataks are common
along the margin of the Inland Ice.
The field work covered three main topics: (1) system-
atic drainage sampling, (2) reconnaissance mineral ex-
ploration, and (3) geological mapping. It was carried out
between 22 July and 30 August by the authors assisted
by two young men from Qaanaaq (Thomassen 2001). A
chartered 75-foot vessel, M/S Kissavik, served as a base,
working from 12 anchorages (Fig. 2). Two rubber din-
ghies enabled access to coastal localities and a heli-
copter was available for a 14-day period. The work was
initiated in the north where the winter sea ice breaks up
first, then continued in Inglefield Bredning to reach the
outer islands and Olrik Fjord at the end of August. This
ensured that reasonable ice conditions were encoun-
tered in all areas, apart from innermost Inglefield
Bredning, north of Josephine Peary Ø, where thick calf
ice rendered navigation impossible. Sixty percent of the
field period was seriously hampered by bad weather,
with seven days completely lost. Regional coverage
was therefore not as thorough as planned.
Geological setting and map status
The Qaanaaq region is underlain by two bedrock
provinces: a high-grade Archaean­Palaeoproterozoic
crystalline shield overlain by the unmetamorphosed
Mesoproterozoic sediments and volcanics of the intra-
cratonic Thule Basin. The profound unconformity
between these units is well preserved. The Thule Basin
straddles the northern extremity of Baffin Bay, and the
western outcrops are in coastal Ellesmere Island,
Canada (Fig. 1). In Greenland, exposures of the Thule
Basin crop out on islands and the outer coastal areas,
bordered on the east by the crystalline shield.
The Qaanaaq region has not been systematically
mapped at a consistent scale. The western part where
the Thule Basin is exposed has been mapped at
1:100 000; the area at the head of Inglefield Bredning,
composed entirely of the crystalline shield, has been
depicted at 1:200 000 (Dawes 1988). The only detailed
mapping undertaken was of the Smithson Bjerge
(Nutman 1984). The Survey's 1:500 000 geological map
sheet (Thule, sheet 5; Dawes 1991) has a northern
border at 78°N; the northernmost part of the project
region around Kap Alexander is featured in Dawes
(1997) and Dawes et al. (2000).
Much of the Survey's mapping work for the Thule
1:500 000 map sheet (1971­1980) was based on shore-
line investigations with only limited helicopter traverses
inland. The helicopter support during Qaanaaq 2001
was reserved for geochemical sampling and mineral
reconnaissance, but enabled some inland areas to be
visited for the first time leading to new geological
observations and revision of some boundaries.
Geological results
Geological results given here are mainly those having
significance for mineral potential. Where not otherwise
stated, rock unit names are those used on the Survey's
1:500 000 geological map sheet (Dawes 1991).
133
Qaanaaq 2001: mineral exploration reconnaissance in
North-West Greenland
Bjørn Thomassen, Peter R. Dawes, Agnete Steenfelt and Johan Ditlev Krebs
Geology of Greenland Survey Bulletin 191, 133­143 (2002) © GEUS, 2002
GSB191-Indhold 13/12/02 11:34 Side 133
background image
134
Kang
erlussuaq
Inglef
ield Br
edning
Olr
ik
Fjo
rd
Mc
Co
rm
ick
Fjo
rd
·
·
·
·
·
·
Nor
thumberland Ø
Qaanaaq
Tik
eraussaq
Red Cliffs
Ka
p Alexander
Qeqer
tat
J
osephine
P
ear
y Ø
Kangerlussuaq
Smithson
Bjerge
Siora
paluk
Ka
p T
rautwine
'Hill 620'
'Mount Gyrfalco'
0
40 km
Inland Ice
Sonntag
Bugt
Morr
is Jesup
Gletsc
her
Bowd
oin Fjord
Rober
tson
Fjor
d
Hubbar
d
Gletsc
her
In
g
l
e
f
ie
ld
L
a
n
d
P
r
u
d
h
o
e
L
a n
d
Scarlet Hear
t
Gletsc
her
Acad
emy B
ugt
Greenland
BB
BI
·
N
EI
MB
CH
P
77
°
30
78
°
72
°
70
°
68
°
66
°
Permanent ice
Surficial deposits
QUATERNARY
MESOPROTEROZOIC
Main fault
Prudhoe Land
supracrustal complex
Undifferentiated gneiss complex
incl. Etah Group of Inglefield Land
Smithson Bjerge
magmatic association
Thule mixed-gneiss complex
ARCHAEAN
PALAEO-
PROTEROZOIC
PRECAMBRIAN SHIELD
Dundas Group
Baffin Bay Group
Nares Strait Group
Smith Sound Group
THULE BASIN
Fig. 1.
Geological map of the Qaanaaq region with place names used in the text; project limits of
Qaanaaq 2001
are shown by
r
ed dashed lines
. Basic sills, that in some areas of
the Dundas Group for
m lar
ge outcrops, are not shown. Only faults af
fecting disposition of groups of the Thule Super
group are de
picted.
Black dots
are settlements;
r
ed dots
other
localities. Inset map:
BB
, Baf
fin Bay;
BI
, Baf
fin Island;
CH
, Clarence Head;
EL
, Ellesmere Island;
MB,
Melville Bugt;
N
, Nanisivik;
P
, Pituf
fik (Thule Air Base).
Red frame
, location
of Qaanaaq region. Compiled from Dawes (1991) and Dawes
et al.
(2000) with modifications from
Qaanaaq 2001
.
GSB191-Indhold 13/12/02 11:34 Side 134
background image
Precambrian shield
Thule mixed-gneiss complex. This is an Archaean
complex of highly deformed amphibolite- to granulite-
facies gneisses of variable lithology and derivation,
with genetically related granitic rocks. The 2001 work
confirmed the intricate association of paragneisses and
orthogneisses and it is clear that some intermixed
packages can only be unravelled by future detailed
mapping. Of note are widespread light coloured garnet-
bearing quartzitic layers interleaved with gneisses. At
the head of Olrik Fjord, these rock associations
contain a rusty unit of banded iron-formation (BIF),
e.g. north-east of `Mount Gyrfalco' (see later under
Mineralisation). Several amphibolite bodies were
found to grade into ultramafic rocks and new occur-
rences of ultramafic bodies were discovered, the
largest being a boudin (c. 500
x 150 m) within ortho-
gneiss at the head of Academy Bugt.
Prudhoe Land supracrustal complex. These supracrustal
rocks, of supposed Palaeoproterozoic age, comprise a
thick succession of pelitic, semi-pelitic and quartzitic
rocks with some mafic units (amphibolite and pyribo-
lite). The supracrustal complex has conspicuous rusty
weathering, and is considered to be a cover sequence
to the Thule mixed-gneiss complex (Fig. 3). Both units
are interleaved by large-scale isoclinal folds. New out-
crops of supracrustal rocks were noted around Bowdoin
Fjord and in Robertson Fjord, and units of marble, not
hitherto known in the succession, were discovered at
Bowdoin Fjord and Morris Jesup Gletscher. This
strengthens our view that the supracrustal rocks are a
correlative of the Etah Group of Inglefield land in
which marble units are common.
Thule Basin
The Thule Supergroup is a thick, multicoloured, main-
ly shallow water sedimentary succession with one
main interval of volcanic rocks. Basic sills are common
at several levels. Five groups are recognised (Dawes
1997), all but one of which (Narssârssuk Group) crop
out in the Qaanaaq region (Fig. 1). The Smith Sound
Group, present north of Sonntag Bugt, represents the
northern basin margin equivalent of the Nares Strait
Group and the overlying Baffin Bay Group.
Access to inland exposures in 2001 resulted in some
adjustments to group/formation distribution on exist-
ing maps. One revision concerns the distribution of
the Nares Strait Group with its volcanic component of
hypabyssal, effusive and pyroclastic rocks and associ-
ated red beds ­ the Cape Combermere Formation
(Dawes 1997). Breccias of the formation have proved
to be mineralised. The Nares Strait Group was deemed
135
Fig. 2. The basic logistics of Qaanaaq 2001 with typical weather:
M/S Kissavik and rubber dinghies with overcast, low cloud and
rain. View is across Olrik Fjord in late August.
Fig. 3. Basement­cover relationship.
Rusty-weathering pelitic and quartzitic
rocks with amphibolites of the
Palaeoproterozoic Prudhoe Land
supracrustal complex overlying darker
gneisses of the Archaean Thule mixed-
gneiss complex. The pelitic schists, rich
in graphite and pyrite, generate several
Landsat anomalies. North side of
Inglefield Bredning, west of Josephine
Peary Ø, with main summit 770 m above
sea level.
GSB191-Indhold 13/12/02 11:34 Side 135
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absent at Tikeraussaq where a postulated fault block
was considered to be draped by the younger Baffin Bay
Group. In 2001, a greenish basaltic unit, at least 20 m
thick and in places veined and brecciated, was located
within a red bed section directly overlying the crystalline
shield: this succession is now referred to the Nares Strait
Group. Similar basaltic rocks are also present at
Bowdoin Fjord, and in 2001 were also identified farther
to the east at Hubbard Gletscher. In North-West Green-
land, the Cape Combermere Formation has its maximum
thickness on Northumberland Ø (c. 200 m); it thins east-
wards towards the basin margin, petering out some-
where between Hubbard Gletscher and Kangerlussuaq.
Structure
Compared to the gneisses and supracrustal rocks of the
Precambrian shield, the Thule Supergroup is little
disturbed; the main structures are fault blocks, grabens
and large-scale flexures, as well as some local folds
associated with faults. Prominent faults vary from
NW­SE-trending, e.g. the fault blocks of Prudhoe Land,
to ESE­WNW-trending as in the Olrik Fjord graben in
which the Dundas Group is downthrown against the
shield (Fig. 1). In 2001, new faults of both trends were
located. Of these, a steep fault at Scarlet Heart Gletscher
(Fig. 1) has appreciable downthrow, juxtaposing the
Baffin Bay Group against gneisses of the shield.
Remote sensing study: a prospecting tool
An integral part of the Qaanaaq 2001 project was a
pre-season remote sensing study of the Qaanaaq
region aimed at delineating areas of potential econom-
ic interest. This study was based on four images of
Landsat 7 ETM data recorded during the season of mini-
mum snow cover. The aim was to pin-point localities
with mineralisation potential by means of mapping
minerals that carry iron oxides (rust zones) and
hydroxyl ions (argillic alteration).
Two different techniques were used for the process-
ing of the data: (1) standard band ratios (Crippen
1989) and (2) feature-oriented Principal Component
Analysis (PCA, also called the Crosta technique after its
originator: Crosta & McMoore 1989). Anomalies were
registered, where an anomaly is defined as a pixel
where both processing techniques gave a digital
number (DN) above 253, corresponding to 0.0008% of
the data, in both the iron oxide and the alteration
images. Using this criterion, 28 anomalies were regis-
tered: two in the Thule mixed-gneiss complex, eleven
in the Prudhoe Land supracrustal complex, four in the
Baffin Bay Group and eleven in the Dundas Group.
For field use the image data were reproduced as paper
copies of Crosta maps.
A rough distinction between the major lithological
units was apparent in the image data with the Dundas
Group showing up as iron oxide stained. Unfortunately,
this meant that small erosional windows or isolated
exposures of the Dundas Group were registered as
anomalies that proved of little interest from a prospect-
ing viewpoint. Previously known zones of alteration
and rust colouring were all represented by anomalies in
the image data and most of these were visited; e.g. the
rusty supracrustal rocks north of Inglefield Bredning
(Fig. 3). However, it became apparent that the statistical
criteria selected had too high a cutoff value, as several
exploration targets encountered during the season were
visible in the image data but not registered as being
abnormal. It transpires that a very small reduction of the
selected DN cutoff value from 253 to 252 would have
resulted in 306 anomalies. All areas of alteration and/or
rust coloration observed in the field were also registered
in the processed Landsat data.
Geochemical survey
The geochemical survey carried out in 2001 forms part
of the reconnaissance-scale geochemical mapping of
Greenland (Steenfelt 1993, 2001). The stream sediment
sampling was undertaken by a two-man team using
dinghy or helicopter. Prior to the field work preferred
sample locations were marked on aerial photographs,
the aim being to obtain an even distribution in first or
second order streams with drainage basins not larger
than 10 km
2
.
At each location representative stream sediment
material from 3 to 15 different sites along c. 50 m of the
stream course was combined to a bulk sample of c. 500 g
and placed in a paper bag. The total gamma-radiation
from rock exposures or predominant boulders was
measured using a scintillometer. A duplicate sample set
of stream sediment material, collected at c. 5% of the
localities, had the purpose of estimating the degree of
local variation. Suitable streams were lacking in some of
the chosen sampling sites, e.g. along glaciers and on
nunataks with low relief. In such cases, scree fines or
soil from patterned ground were sampled instead of
stream sediment.
136
GSB191-Indhold 13/12/02 11:34 Side 136
background image
The sample bags were provisionally dried onboard
the ship, and subsequently packed and shipped to
Copenhagen where the sediments were dried, sieved
and split. The fine fractions (< 0.1 mm) were analysed
at Activation Laboratories Ltd, Canada, the 0.1 to 1 mm
fractions were archived while fractions above 1 mm
were discarded. Major elements were determined by
X-ray fluorescence spectrometry using fused samples;
trace elements were determined by a combination of
instrumental neutron activation analysis (INAA) and
inductively coupled plasma emission spectrometry
(ICP-ES).
Results
A total of 343 stream sediment samples from 331 loca-
tions were analysed. Summary results are shown in
Table 1 for 37 trace elements together with lower
detection limits for the analytical methods. In cases
where the same trace element has been determined by
both INAA and ICP-ES the most reliable data are
presented. Complete evaluation of the chemical data
has yet to be undertaken, and here only some features
of interest to mineral exploration are presented.
High concentrations of one or more elements in a
sample may reflect mineralisation, or the presence of
rock units with unusual chemistry. Figure 4 shows all
sample locations together with locations with high
concentrations of Au and the base metals Cu, Ni, Pb
and Zn. The highest concentrations, i.e. anomalies, are
defined here as those above the 98th percentile of the
frequency distribution for an element.
Gold anomalies are scattered, with no clusters
suggesting mineralisation of any particular stratigraph-
ical unit or tectonic structure. However, the three
anomalies occurring in the Thule Supergroup, i.e. from
Northumberland Ø, the snout of Hubbard Gletscher
and the south coast of Inglefield Bredning, are tenta-
tively related to occurrences of volcanic rocks of the
Nares Strait Group (Cape Combermere Formation). The
remaining two anomalies are sited on shield lithologies.
The base metal anomalies are all associated with
shield lithologies. Two conspicuous clusters are with-
in the Thule mixed-gneiss complex. The combination
of high Zn, Cu and Ni is usually attributable to mafic
volcanic rocks (now amphibolite); the data therefore
suggest that such rocks are part of the mixed-gneiss
complex both east of the snout of Hubbard Gletscher
(see Fig. 6) and in southern Smithson Bjerge. The two
Pb-anomalies east of Hubbard Gletscher are in streams
draining the Prudhoe Land supracrustal complex. These
samples also have very high concentrations of Th and
rare earth elements (REE). The highest values of Th
and REE are over 10 times higher than the median
values, and all anomalous samples are from streams
within the Prudhoe Land supracrustal complex. Meta-
sedimentary units enriched in heavy minerals such as
monazite and garnet are probably the source of these
anomalies.
The anomalous values of Zn and Pb are not so
much higher than the median values, that the scattered
137
Table 1. Summary of chemical analyses of the < 0.1 mm
grain size fraction of 343 stream sediment samples
from the Qaanaaq region
All elements in ppm, except Au (ppb) and S (%).
Analyses by Activation Laboratories Ltd, Ontario, Canada.
ICP-ES: inductively coupled plasma emission spectrometry.
INAA: instrumental neutron activation analysis.
l.l.d.: lower limit of detection.
perc.: percentile of the frequency distribution.
Element
Method
l.l.d.
Maximum
Median
98th perc.

Au (ppb)
INAA
2
55
< 2
8
As
INAA
0.5
48
2
9
Ba
INAA
50
5400
690
1400
Br
INAA
0.5
197
3
72
Co
INAA
1
56
20
43
Cr
INAA
2
350
108
280
Cs
INAA
1
9
< 1
7
Hf INAA
1
85
16
56
Rb
INAA
15
240
84
197
Sb
INAA
0.1
1
< 0.1
1
Sc
INAA
0.1
42
16
32
Ta
INAA
0.5
6
< 0.5
4
Th
INAA
0.2
240
17
113
U
INAA
0.5
18
3
14
W
INAA
1
19
< 1
4
La
INAA
0.5
661
53
343
Ce
INAA
3
1200
110
657
Nd
INAA
5
470
46
245
Sm
INAA
0.1
63
8
33
Eu
INAA 0.2
5
2
4
Tb
INAA
0.5
5
< 0.5
2
Yb
INAA
0.2
9
3
6
Lu
INAA
0.05
1
< 0.05
1
Ag
ICP-ES
0.3
3
1
3
Cd
ICP-ES
0.3
2
< 0.3
1
Cu
ICP-ES
1
151
33
115
Mn
ICP-ES
1
5099
656
1510
Mo
ICP-ES
1
15
2
7
Ni
ICP-ES
1
245
35
138
Pb
ICP-ES
1
77
19
47
Zn
ICP-ES
1
225
67
194
Be
ICP-ES
1
3.3
1.4
2.7
Bi
ICP-ES
2
3.7
< 2
2.5
Sr
ICP-ES
2
578
187
463
V
ICP-ES
2
269
109
212
Y
ICP-ES
1
69
23
47
S (%)
ICP-ES
0.01
0.80
0.03
0.21
GSB191-Indhold 13/12/02 11:34 Side 137
background image
occurrences outside the clusters are considered indica-
tive of mineralisation. Three Cu anomalies are associ-
ated with the Undifferentiated gneiss complex, but
again the concentrations are not sufficiently high as to
suggest significant mineralisation.
Mineral exploration
Limited mineral exploration has previously been
carried out in the Qaanaaq region. In 1969 Greenarctic
Consortium discovered malachite-stained sandstone at
a locality known as `Hill 620' in Olrik Fjord (Greenarctic
1971). In 1975 and 1977 the Geological Survey of Green-
land (GGU) investigated selected mineral occurrences
found during regional mapping (Cooke 1978), and in
1978 BIF was recorded at Smithson Bjerge by Nutman
(1984). Nunaoil A/S explored the Qaanaaq region in
1994 and 1995, and reported scattered malachite in the
Thule Supergroup as well as pyrite in a variety of
settings (Gowen & Sheppard 1994; Gowen & Kelly
1996). Several mineralised rock samples from the
Qaanaaq region collected by Greenlandic residents
have been submitted to the Greenland mineral hunt
programme, Ujarassiorit (Dunnells 1995).
During the 2001 field work a systematic visual
inspection for signs of mineralisation was attempted
along all the accessible coasts of the Qaanaaq region.
The work was carried out partly as shoreline prospect-
ing ­ observations from a rubber dinghy sailing slowly
along the coast, combined with onshore investigations
of promising localities ­ and partly as traverses of later-
al and terminal moraines of active glaciers looking for
mineralised blocks. This work was supplemented by
limited helicopter-supported checks of inland locali-
ties. In addition to this reconnaissance work, special
attention was paid to anomalies detected on Landsat
images, known mineral indications, Ujarassiorit local-
ities, and promising lithologies and structures. Since
previous work had concentrated on the Thule Super-
138
Kangerlussuaq
Inglefield Bredning
0
40 km
I n l a n d I c e
Qaanaaq
Qeqertat
Siorapaluk
Sample locality
Ni
Cu
Zn
Pb
Au
138 ppm
115 ppm
200 ppm
50 ppm
10 ppb
>
>
>
>
>
77
°
30
78
°
72
°
70
°
68
°
66
°
Fig. 4. Map of the Qaanaaq region showing anomalous concentrations of gold, copper, lead, zinc and nickel based on stream sedi-
ment samples. For location and place names, see Fig. 1. Red dashed lines demarcate the project area.
GSB191-Indhold 13/12/02 11:34 Side 138
background image
group, our emphasis during Qaanaaq 2001 was on
the various lithologies of the Precambrian shield.
A total of 152 mineralised rock samples were
collected, mainly loose blocks from moraines, stream
beds and screes. All have been analysed by Activation
Laboratories Ltd, Canada, for a suite of elements
including precious and base metals, and 40 of the
samples have also been assayed for gold, platinum
and palladium. The main results are summarised in
Table 2 and commented on below.
Thule mixed-gneiss complex
Magnetite, often in the form of iron-formation, is
common in paragneiss blocks wherever the Thule
mixed-gneiss complex crops out. Many of these blocks
are BIF consisting of mm- to cm-scale interbedded mag-
netite, silicates and quartz rocks, while others are near
massive magnetite-silicate rocks without any obvious
macrostructure. A new occurrence was found north-east
of `Mount Gyrfalco' (Fig. 5), associated with a rust zone
registered as a Landsat anomaly, and consisting of a
c. 20 m thick unit with a strike length of approximately
500 m. It comprises cm-scale interbedded magnetite,
quartz, pyroxene and garnet with minor iron sulphides.
Chip samples over 6.5 m returned 30.5% Fe, 2.1% Mn,
0.8% S and 8 ppb Au.
Ferruginous quartzite akin to silicate facies BIF occurs
on Smithson Bjerge (Nutman 1984). Blocks of compa-
rable quartz-garnet(-pyroxene) rocks with disseminated
pyrrhotite, magnetite and traces of chalcopyrite were
encountered at several localities in the eastern part of
139
Fig. 5. New iron-formation locality in the
Thule mixed-gneiss complex, north-east
of `Mount Gyrfalco', Olrik Fjord.
Above: general view eastwards of tightly
folded, rusty gneisses: arrow marks an
isoclinal fold hinge. The regional plateau
surface in the distance is 500­800 m
high. The cliff with the rusty scree in the
left foreground is about 400 m high.
Below: detail of banded iron-formation
above with the magnet pen 12 cm long.
GSB191-Indhold 13/12/02 11:34 Side 139
background image
the region, but returned only slightly enhanced gold
and copper values (max. 83 ppb Au and 931 ppm Cu).
Faint malachite staining, caused by oxidation of
minor disseminated pyrite and chalcopyrite, was ob-
served over a distance of 3­4 km in steep coastal cliffs
of banded gneisses east of the snout of Hubbard
Gletscher; this is also marked by a multi-element
anomaly in the stream sediment samples (Fig. 6). Rock
samples were collected at one locality, but these
returned no significant metal values. Faint malachite
coatings caused by minor disseminated pyrite and chal-
copyrite were also observed on amphibolitic and ultra-
mafic lenses and pods in the gneisses; samples returned
up to 31 ppb Au, 8 ppb Pt, 19 ppb Pd, 1748 ppm Cu
and 1298 ppm Ni.
Undifferentiated gneiss complex
A number of moraine blocks derived from this unit (see
Fig. 1) contain disseminated iron sulphides, graphite and
traces of chalcopyrite. Some samples are slightly en-
riched in gold and base metals (Table 2).
Prudhoe Land supracrustal complex
This unit is characterised by conspicuous red and
yellow rust zones in sulphidic semi-pelitic schist
(Gowen & Sheppard 1994), and these correspond to
concentrations of Landsat anomalies (Fig. 3). Checks
east of Bowdoin Fjord revealed units of highly graphitic
and pyritic schist several tens of metres thick with
intense argillic alteration; remobilisation of pyrite into
veinlets in quartz-rich pinch-and-swell layers is inter-
preted as due to a hydrothermal overprint. Analyses of
chip and grab samples show no significant concentra-
tions of economic metals (Table 2).
Nares Strait Group
Blocks of malachite-stained volcanic breccia on Nor-
thumberland Ø were reported by Gowen & Sheppard
(1994), and almost certainly derive from the Cape
Combermere Formation. This mineralisation was
found to consist of specks of malachite-covellite-chal-
cocite and hematite in moraine boulders collected
below the Kiatak fault, a major NW­SE-trending dislo-
cation (Fig. 1) juxtaposing the Dundas and Nares Strait
140
Geological unit
Samples
Au ppb
Cu ppm
Pb ppm
Zn ppm
Ni ppm
Ti%
Fe%
S%
6
< 2­5
11­1081
< 3­13
3­104
4­63
0.02­3.06
1.2­10.5
0.03­3.40
10
< 2­5
12­426
< 3­157
3­20986
3­48
0.02­0.49
2.0­9.4
0.07­4.46
< 2
57
12
76
26
0.13
5.5
1.82
10
< 2­7
7­15247
< 3­15
4­47
1­46
0.01­0.39
0.2­3.0
0.03­2.20
< 2
251
10
6
5
0.05
1.1
0.15
6
< 2
30­10167
< 3­12
22­60
44­119
0.22­0.46
4.3­10.6
0.01­0.18
< 2
920
5
33
65
0.38
4.6
0.01
14
< 2­11
8­886
< 3­135
< 1­637
< 1­581
< 0.01­3.12
0.4­21.7
0.04­18.21
< 2
40
13
31
26
0.09
6.3
3.17
25
< 2­76
15­1901
< 3­171
37­1769
7­3582
0.06­1.82
1.8­15.5
0.12­6.05
< 2
354
11
98
90
0.43
8.8
1.43
81
< 2­83
8­1748
< 3­45
22­793
4­3282
0.01­1.72
1.8­35.6
0.01­10.15
< 2
123
< 3
93
50
0.24
14.8
1.11

Numbers are ranges and medians.
Analyses by Activation Laboratories Ltd, Ontario, Canada.
Analytical methods: Inductively coupled plasma emission spectrometry: Cu, Pb, Zn, Ni, Ti, S.
Instrumental neutron activation analysis: Au, Fe.
Table 2. Summary of selected elements for mineralised rock samples from the Qaanaaq region
Quartz veins
and basic dykes
Dundas Group
Baffin Bay
Group
Nares Strait
Group
Prudhoe Land
supracrustal
complex
Undifferentiated
gneiss complex
Thule mixed-
gneiss complex
GSB191-Indhold 13/12/02 11:34 Side 140
background image
Groups (Dawes 1997). Samples returned up to 1.0%
Cu, 11 ppm Ag and 0.9% Ba. Malachite staining has
also been reported from the basal clastics of the Nares
Strait Group on Northumberland Ø (Jackson 1986) as
well as in the Cape Combermere Formation at Clarence
Head, Ellesmere Island (Frisch & Christie 1982).
Baffin Bay Group
Faint malachite staining on pale sandstones was ob-
served at several localities in the Qaanaaq Formation of
the Baffin Bay Group. This is caused by oxidation of
flecks and disseminations of minor pyrite and chal-
copyrite. The highest copper concentrations were en-
countered at Red Cliffs and `Hill 620'. At Red Cliffs
dm-thick layers of interbedded pale sandstone and
black shales occur in a small outcrop. In addition to
faint malachite staining, interstitial chalcopyrite and
minor pyrite were found in a composite sample which
returned 1.5% Cu and 0.8% Ba. `Hill 620' comprises an
isolated, 100
x 100 m showing adjacent to an E­W-strik-
ing fault and covered by cm­dm-sized blocks of mala-
chite-sprinkled white sandstone. The only primary
copper mineral seen under the microscope is chal-
copyrite as few µ sized disseminated grains. A compos-
ite sample returned 0.4% Cu and 5 ppm Ag.
Dundas Group
The Dundas Group on Northumberland Ø shows vari-
ous signs of mineralisation. As noted by Dawes (1997),
stratiform pyrite is common in sandy shales, but no
signs of base metal concentrations were found associ-
ated with this mineralisation in 2001. In a sequence of
interbedded shale and stromatolitic limestone, minor
sphalerite was observed at the base of a limestone unit
(Fig. 7). A composite sample returned 2.1% Zn and
0.01% Pb. Also worthy of note is the observation by
Marcos Zentilli (personal communication 2002) in the
same area of minor galena-barite mineralisation at a
basic sill ­ shale contact.
Structures
The pyrite mineralisation along the syn- to post-depo-
sitional southern boundary fault of the Olrik Fjord
graben noted by Gowen & Sheppard (1994) was
checked at one locality, but no gold or base metals
occur in the samples collected.
141
Fig. 7. Interbedded dark shales and stromatolitic carbonate beds,
Dundas Group, north-eastern Northumberland Ø. The base of
the carbonate bed (at the notebook) contains zinc mineralisation.
Fig. 6. Mixed orthogneisses and paragneisses, east of the snout
of Hubbard Gletscher. The pale units are garnet-rich quartzites
and granitic sheets. Sporadic malachite staining occurs for 3­4 km
along these c. 600 m high cliffs and the coast constitutes a multi-
element geochemical anomaly.
GSB191-Indhold 13/12/02 11:34 Side 141
background image
Concluding remarks
Observations during Qaanaaq 2001 of magnetite-rich
rocks in blocks and outcrops in the Thule mixed-
gneiss complex may be interpreted as the northward
extension of the Archaean magnetite province that
stretches for 350 km along the coast of Melville Bugt
and into the Pituffik (Thule Air Base) area (Dawes
1976, 1991; Dawes & Frisch 1981). This Greenland iron
province is a prime candidate for correlation with the
Algoma-type iron deposits of the Mary River Group of
northern Baffin Island (Jackson 2000). In addition to
iron, BIF provinces have a potential for gold, so much
so that in many regions of the world BIF is used as an
exploration guide for gold (Kerswill 1996).
The banded gneisses east of the snout of Hubbard
Gletscher with their malachite staining and multi-
element geochemical anomaly have a base metal
potential. These gneisses, as well as those in the
anomalous area of southern Smithson Bjerge, warrant
further attention.
No convincing signs of economic mineral concen-
trations were found in the hydrothermally overprinted
pyrite-rich graphitic schists of the Prudhoe Land
supracrustal complex, but this unit needs closer scruti-
ny to verify whether it has gold and base metal poten-
tial. The stream sediment geochemistry suggests the
presence of metasedimentary units with concentra-
tions of REE-rich minerals.
An interesting result of the Landsat study is the pres-
ence of rust zones in the Prudhoe Land supracrustal
complex and their paucity in other shield lithologies.
In Inglefield Land to the north, rust zones caused by
iron sulphides and graphite are concentrated in supra-
crustal rocks of the Etah Group and derived para-
gneisses (Dawes et al. 2000; Thomassen et al. 2000).
This supports our view that the Prudhoe Land supra-
crustal complex is a correlative of the Etah Group.
The copper mineralisation in the Cape Combermere
Formation of the Nares Strait Group resembles a
`volcanic redbed copper' deposit type (Kirkham 1996),
possibly associated with the NW­SE-trending Kiatak
fault crossing Northumberland Ø. The geochemical
results for this volcanic formation also indicate a gold
potential, and the formation and the faults dissecting it
warrant further exploration. The disseminated copper
mineralisation in sandstones of the Qaanaaq For-
mation of the Baffin Bay Group is probably of diagenetic
origin, perhaps controlled by local faults. It constitutes a
low-priority exploration target.
The carbonates of the Dundas Group with their zinc
mineralisation, albeit of modest size, show a potential
for carbonate-hosted lead-zinc deposits, and in this
respect it is worth noting that extensive outcrops of the
group occur south of the Qaanaaq region. Also of rele-
vance is the fact that commercial lead-zinc concentra-
tions exist in carbonate rocks of comparable age at
Nanisivik in the coeval Borden Basin of Baffin Island,
Canada (Olson 1984).
Acknowledgements
We gratefully acknowledge the help and support of the following
persons during the field programme: Jes Burghardt, Nuuk, skip-
per of M/S Kissavik and his crew; Grønlandsfly A/S pilot Glenn
Lindström; field assistants Piuaitsoq Petersen and Peter Peary
Aleqatsiaq from Qaanaaq; Hans Jensen and company, Hotel
Qaanaaq; and Svend Erik Ascaneus, Geophysical Observatory of
the Danish Meteorological Institute, Qaanaaq.
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Authors' addresses
B.T., P.R.D. & A.S., Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail:
bth@geus.dk
J.D.K., Vejdammen 68, DK-2840 Holte, Denmark.
GSB191-Indhold 13/12/02 11:34 Side 143
Review of Greenland Activities 2001, pp 133-143