|
|
|||||||||||||||||||||||
|
||||||||||||||||||||||||
Theme Magazines and Fact Sheets
EXPLORATION AND MINING IN GREENLANDGreenland Mineral Resources
Fact Sheet No. 15
Download pdf-file go_fs15.pdf (~500 kbyte). Requires pdf-reader, Acrobat GSview or similar
The Palaeozoic Franklinian Basin extends for 2500
km EW through the Canadian Arctic Islands and
northern Greenland. In Greenland, the basin bor-
ders the Arctic Ocean and is nearly 1000 km long
and up to 200 km wide. Reconnaissance mineral
exploration in the 1990s has demonstrated wide-
spread lead-zinc mineralisation and the basin is
now believed to offer an excellent potential for
sedimentary lead-zinc deposits.
km EW through the Canadian Arctic Islands and
northern Greenland. In Greenland, the basin bor-
ders the Arctic Ocean and is nearly 1000 km long
and up to 200 km wide. Reconnaissance mineral
exploration in the 1990s has demonstrated wide-
spread lead-zinc mineralisation and the basin is
now believed to offer an excellent potential for
sedimentary lead-zinc deposits.
Geological setting
The Greenland part of the Franklinian Basin was mapped
systematically by the Geological Survey of Greenland in
the period 197885. Throughout the Early Palaeozoic,
the basin was divided into a southern shelf and slope
and a northern deep-water trough. The shelf succession
dominated by carbonates reaches 4 km in thickness
whereas the trough deposits that are dominately silici-
clastic rocks have a composite thickness of c. 8 km. The
boundary between shelf and trough facies shifted posi-
tion with time and southerly basin expansion in the
Silurian resulted in a final foundering of the shelf. This
facies border, the so-called Navarana Fjord Escarpment,
was a dominant EW palaeo-topographic feature with a
relief of over 1 km. Stream-sediment zinc anomalies are
associated with this structure. Sedimentation was brought
to an end by the late Devonianearly Carboniferous
Ellesmerian orogeny. The resulting orogenic belt is char-
acterised by EW- to NESW-trending folds, with defor-
systematically by the Geological Survey of Greenland in
the period 197885. Throughout the Early Palaeozoic,
the basin was divided into a southern shelf and slope
and a northern deep-water trough. The shelf succession
dominated by carbonates reaches 4 km in thickness
whereas the trough deposits that are dominately silici-
clastic rocks have a composite thickness of c. 8 km. The
boundary between shelf and trough facies shifted posi-
tion with time and southerly basin expansion in the
Silurian resulted in a final foundering of the shelf. This
facies border, the so-called Navarana Fjord Escarpment,
was a dominant EW palaeo-topographic feature with a
relief of over 1 km. Stream-sediment zinc anomalies are
associated with this structure. Sedimentation was brought
to an end by the late Devonianearly Carboniferous
Ellesmerian orogeny. The resulting orogenic belt is char-
acterised by EW- to NESW-trending folds, with defor-
mational effects most intense in the north, and broadly
parallel to the main facies boundaries within the basin.
Only in the northern part of Peary Land have rocks been
affected by low-grade regional metamorphism.
parallel to the main facies boundaries within the basin.
Only in the northern part of Peary Land have rocks been
affected by low-grade regional metamorphism.
Lead-zinc mineralisation
The remote region of northern Greenland has seen very
little commercial activity. Encouraged by the results ob-
tained in the Canadian part of the basin, especially the
opening of the Polaris lead-zinc mine in 1982, Platinova
A/S and partners reconnoitred the Greenland part in
1992-1999. The main exploration effort was on the
Citronen Fjord deposit of Peary Land discovered in 1993.
It appears that lead-zinc mineralisation occurs in both
deep-water and shelf facies.
little commercial activity. Encouraged by the results ob-
tained in the Canadian part of the basin, especially the
opening of the Polaris lead-zinc mine in 1982, Platinova
A/S and partners reconnoitred the Greenland part in
1992-1999. The main exploration effort was on the
Citronen Fjord deposit of Peary Land discovered in 1993.
It appears that lead-zinc mineralisation occurs in both
deep-water and shelf facies.
Deep-water trough
The deep-water clastic sediments have so far been the
main target for exploration and host the only in-detail
investigated occurrence, the Citronen Fjord stratiform
massive sulphide deposit. This comprises four separate
areas with pyrite, sphalerite and silver-poor galena min-
eralisation. The sulphides occur in three main levels within
a 200 m thick sequence of Ordovician black shales and
chert. Investigations by Platinova in 1993-1997 com-
prised geological mapping, gravity and electromagnetic
surveys, and the drilling of 143 exploration holes total-
ling 32,400 m. Total sulphides are estimated to exceed
main target for exploration and host the only in-detail
investigated occurrence, the Citronen Fjord stratiform
massive sulphide deposit. This comprises four separate
areas with pyrite, sphalerite and silver-poor galena min-
eralisation. The sulphides occur in three main levels within
a 200 m thick sequence of Ordovician black shales and
chert. Investigations by Platinova in 1993-1997 com-
prised geological mapping, gravity and electromagnetic
surveys, and the drilling of 143 exploration holes total-
ling 32,400 m. Total sulphides are estimated to exceed
The lead and zinc potential of the
Franklinian Basin in North Greenland
Franklinian Basin in North Greenland
Fact Sheet
No. 15
Greenland
Mineral
Resources
EXPLORATION
AND
MINING IN
GREENLAND
No. 15
Greenland
Mineral
Resources
EXPLORATION
AND
MINING IN
GREENLAND
°
A r c t i c O c e a n
Wandel
Sea
Caledonian: Proterozoic-Palaeozoic
Pearya: Proterozoic-Palaeozoic
Intracratonic mid-late Proterozoic
Early Proterozoic crust
Archaean & reworked Archaean
Late Palaeozoic Tertiary
Palaeozoic, trough
Palaeozoic, marginal
Franklinian
Basin
Basin
Palaeozoic, shelf-platform
Ellesmere
Island
Canada
Peary Land
Station
Nord
Alert
Washington
Land
Inland
Ice
200 km
90
°
90
°
60
°
60
°
30
°
Navarana Fjord
Escarpment
80
80 °
500 km
Greenland
Nares Strait
1
2
3
C
a
n
ad
a
°
Geological map of North
Greenland and north-eastern
Canada showing main lead-
zinc occurrences: 1. Citronen
Fjord Deposit, 2. Petermann
Prospect, 3. Cass Prospect.
Greenland and north-eastern
Canada showing main lead-
zinc occurrences: 1. Citronen
Fjord Deposit, 2. Petermann
Prospect, 3. Cass Prospect.
350 million tons with an estimated 20 million tons
grading 7% Zn and 1% Pb. A high-grade zone of
1.1 million tons diluted and recoverable ore with
9.4% Zn and 0.6% Pb has been determined in
one area.
grading 7% Zn and 1% Pb. A high-grade zone of
1.1 million tons diluted and recoverable ore with
9.4% Zn and 0.6% Pb has been determined in
one area.
Platform, shelf and slope facies
Mineralisation occurs in various settings in the
shallow-water facies. In the folded marginal shelf
and slope Cambro-Ordovician sequence, minor zinc-
lead-barium mineralisation, often related to carbon-
ate debris flows, is common in the central and west-
ern part of the basin. The mineralisation appears
to be controlled by the high permeability of pyro-
bitumen-bearing, partly silicified breccias.
shallow-water facies. In the folded marginal shelf
and slope Cambro-Ordovician sequence, minor zinc-
lead-barium mineralisation, often related to carbon-
ate debris flows, is common in the central and west-
ern part of the basin. The mineralisation appears
to be controlled by the high permeability of pyro-
bitumen-bearing, partly silicified breccias.
In undeformed Cambro-Ordovician platform car-
bonates, mineralisation is best known from the west-
ern part of the basin, where GEUS discovered the
Petermann Prospect in 1997. This comprises pyrite-
sphalerite-smithsonite-galena mineralisation associ-
ated with dolomite alteration of the hosting Ordo-
vician limestone and is traceable for 19 km along an
E-W fault zone. Grab samples yielded up to 41% Zn,
13% Pb and 211 ppm Ag, but 925 m diamond
drilling revealed no zones of economic grade; the
most significant intercept was 23 metres of barren
massive pyrite. The Cass Prospect, 50 km to the SW,
comprises five areas of sphalerite-galena-barite min-
eralisation hosted by dolomitised Cambrian lime-
stones over a 4 km structural zone open to the east
and west. The one hole drilled has a best interval of
1.2 m grading 8.4% Zn, 0.04% Pb and 94 ppm Ag.
ern part of the basin, where GEUS discovered the
Petermann Prospect in 1997. This comprises pyrite-
sphalerite-smithsonite-galena mineralisation associ-
ated with dolomite alteration of the hosting Ordo-
vician limestone and is traceable for 19 km along an
E-W fault zone. Grab samples yielded up to 41% Zn,
13% Pb and 211 ppm Ag, but 925 m diamond
drilling revealed no zones of economic grade; the
most significant intercept was 23 metres of barren
massive pyrite. The Cass Prospect, 50 km to the SW,
comprises five areas of sphalerite-galena-barite min-
eralisation hosted by dolomitised Cambrian lime-
stones over a 4 km structural zone open to the east
and west. The one hole drilled has a best interval of
1.2 m grading 8.4% Zn, 0.04% Pb and 94 ppm Ag.
Finally, Silurian reef carbonates in the western
part of the basin may host
sphalerite-pyrite-gale-
na-fluorite-barite mineralisation in zones of calcite
veining in organic-rich carbonate rocks. The maxi-
mum strike length of zones with intermittent min-
eralisation is about 1400 m.
veining in organic-rich carbonate rocks. The maxi-
mum strike length of zones with intermittent min-
eralisation is about 1400 m.
Concluding remarks
The lead-zinc mineralisation of the Franklinian Basin
is of SEDEX-type in the clastic trough sediments
and of Mississippi Valley-type in the platform and
shelf carbonates. The under-explored basin is be-
lieved to be an excellent target for lead-zinc explo-
ration, especially since the shrinking ice cover of
the Arctic Ocean will probably facilitate sea trans-
portation in the not to distant future, thereby low-
ering exploration and exploitation costs.
is of SEDEX-type in the clastic trough sediments
and of Mississippi Valley-type in the platform and
shelf carbonates. The under-explored basin is be-
lieved to be an excellent target for lead-zinc explo-
ration, especially since the shrinking ice cover of
the Arctic Ocean will probably facilitate sea trans-
portation in the not to distant future, thereby low-
ering exploration and exploitation costs.
Key references
Andersen, E.O. 2001:
Mining concept for the Citronen
Fjord
zinc deposit, NE Greenland. In: Olsen, H.K., Lorentzen, L.
&
Rendal, O. (eds): Mining in the Arctic, 5160. Lisse,
The
Netherlands: A.A. Balkema Publishers.
Dawes, P.R. 2004:
Explanatory notes to the Geological
map of
Greenland, 1:500 000, Humboldt Gletscher, Sheet
6.
Geological Survey of Denmark and Greenland Map Series
1,
48 pp. + map.
Peel, J. & Sønderholm, M. (eds) 1991:
Sedimentary
basins of
North Greenland. Bulletin Grønlands Geologiske
Undersøgelse
160
, 164 pp.
van der Stijl, F.W. & Mosher, G.Z. 1998:
The
Citronen Fjord
massive sulphide deposit, Peary Land, North Greenland:
dis-
covery, stratigraphy, mineralization and structural
setting.
Geology of Greenland Survey Bulletin
179
, 40
pp.
Geological Survey of Denmark
and Greenland (GEUS)
Øster Voldgade 10
DK-1350 Copenhagen K
Denmark
Tel: (+45) 38 14 20 00
Fax.: (+45) 38 14 20 50
E-mail: geus@geus.dk
Internet: www.geus.dk
Bureau of Minerals and Petroleum
(BMP)
Government of Greenland
P.O. Box 930
DK-3900 Nuuk
Greenland
Tel: (+299) 34 68 00
Fax.: (+299) 32 43 02
E-mail: bmp@gh.gl
Internet: www.bmp.gl
Greenland Mineral Resources
Author
B. Thomassen, GEUS
Editor
K. Secher, GEUS
Layout
C.E. Thuesen, GEUS
Photographs
GEUS unless otherwise stated
Printed
February 2007 © GEUS
Printers
Schultz Grafisk
ISSN
1602-8171
Cass Prospect: galena crystals in a pale dolomitic
matrix
etched out on the weathered surface. Cut surface shows
variety of crystal forms, some with skeletal growth struc-
tures.
etched out on the weathered surface. Cut surface shows
variety of crystal forms, some with skeletal growth struc-
tures.
Citronen Fjord Deposit: 3.6 cm wide
drill-core showing fine-grained lami-
nated pyrite and sphalerite in black
mudstone. Zinc concentration in the
upper sulphide layer is 2530% and
in the lower layer 13%.
drill-core showing fine-grained lami-
nated pyrite and sphalerite in black
mudstone. Zinc concentration in the
upper sulphide layer is 2530% and
in the lower layer 13%.
GOFactsheet 15 23/02/07 14:01 Page 2
