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Theme Magazines and Fact Sheets
EXPLORATION AND MINING IN GREENLANDGreenland Mineral Resources
Fact Sheet No. 13
Download pdf-file go_fs13.pdf (~220 kbyte). Requires pdf-reader, Acrobat GSview or similar
The classic Skaergaard intrusion hosts a large ton-
nage PGE-Au-Ti-V-Fe deposit. The inferred tonnage
is 1,500 million tonnes. The precious metals are
hosted in a series of stratiform sulphide-bearing
levels in ilmenite and magnetite rich, layered gabbro.
The mineralisation formed at magmatic tempera-
tures in the upper part of the intrusion in strongly
fractionated basaltic magma. The mineralisation
was little affected by later remobilisation and the
dominant precious metals are skaergaardite (PdCu)
and tetraauricupride (AuCu).
nage PGE-Au-Ti-V-Fe deposit. The inferred tonnage
is 1,500 million tonnes. The precious metals are
hosted in a series of stratiform sulphide-bearing
levels in ilmenite and magnetite rich, layered gabbro.
The mineralisation formed at magmatic tempera-
tures in the upper part of the intrusion in strongly
fractionated basaltic magma. The mineralisation
was little affected by later remobilisation and the
dominant precious metals are skaergaardite (PdCu)
and tetraauricupride (AuCu).
The Skaergaard intrusion
The 54.5 Ma old Skaergaard intrusion is located at 68°N
in the volcanic rifted margin along the coast of East
Greenland. The intrusion was emplaced during the build
up of the regional flood basalts and the initial stages of
continental rifting and seafloor spreading in the North
Atlantic. The intrusion is currently modelled as a box-
like magma chamber app. 11 by 7.5 km in surface area
with an original stratigraphy of c. 3.8 km. The original
volume was ca. 300 km3.
in the volcanic rifted margin along the coast of East
Greenland. The intrusion was emplaced during the build
up of the regional flood basalts and the initial stages of
continental rifting and seafloor spreading in the North
Atlantic. The intrusion is currently modelled as a box-
like magma chamber app. 11 by 7.5 km in surface area
with an original stratigraphy of c. 3.8 km. The original
volume was ca. 300 km3.
Crystallisation up from the floor, along the walls and
down from the roof resulted in three main formations:
(1) The Upper Border Series under the roof (UBS, c. 50 km3).
(2) The Marginal Border Series along the walls (MBS, c.
50 km3).
(3) The Layered Series (LS, c. 200 km3) accumulated up
from the floor of the intrusion.
The last rock unit to crystallise is the Sandwich Horizon
(SH) at the interface between LS and UBS, c. 600 m
below the roof. The intrusion is rotated c. 15° to the
south and most of the stratigraphy is exposed due to
erosion of the northern parts.
(SH) at the interface between LS and UBS, c. 600 m
below the roof. The intrusion is rotated c. 15° to the
south and most of the stratigraphy is exposed due to
erosion of the northern parts.
The magma solidified in concentric zones toward the
centre of the intrusion. Phase layering, i.e., liquidus par-
ageneses, and cryptic variation in liquidus minerals
allow a subdivision of the intrusion. The cryptic variation
in minerals is significant. Olivine evolves from c. Fo70 to
ageneses, and cryptic variation in liquidus minerals
allow a subdivision of the intrusion. The cryptic variation
in minerals is significant. Olivine evolves from c. Fo70 to
A world class deposit
in the Skaergaard intrusion
in the Skaergaard intrusion
1600 m
1000 m
sea level
Basalt
Marginal
Border
Series
Gneiss
North
South
Hid
den Zone
Lower Zone
Mid
dle Zone
Basistoppen Sheet
Upper
Zone
Marginal
Border
Series
1600 m
1000 m
sea level
Triple Group:
PGE-Au Horizons
Ice
Upper Border Series
Fault
The three leuco layers of the Triple Group near the top of
Wagertoppen (background) and in the Pukugatryggen (fore-
ground right).
Wagertoppen (background) and in the Pukugatryggen (fore-
ground right).
N-S section through the
Skaergaard intrusion.
Mineralisation in the upper
100 metres of Middle
Zone.
Skaergaard intrusion.
Mineralisation in the upper
100 metres of Middle
Zone.
Fo
1
, and plagioclase from c. An 70 to An10. The
deepest gabbros in LS are not exposed and referred
to as the Hidden Zone (HZ). The exposed rocks of
LS are divided in Lower Zone (LZ), Middle Zone (MZ),
and Upper Zone (UZ).
to as the Hidden Zone (HZ). The exposed rocks of
LS are divided in Lower Zone (LZ), Middle Zone (MZ),
and Upper Zone (UZ).
The mineralisation
The mineralisation is hosted in the Triple Group in
the upper part of MZ after the crystallisation of c.
70 % of the parental ferrobasalt magma. The Triple
Group is the name of a c. 100 m stratigraphy char-
acterised by three, distinct, leucogabbro layers. The
mineralisation is located in the stratigraphic section
from the base of the lower leucogabbro layer and to
just above the second leucogabbro layer. The miner-
alisation is composed of five main levels and in total
ten well-defined levels of enrichment in PGE (Pd-lev-
els). The stratigraphic separation between main Pd-
levels is c. 10 m. All Pd-levels are perfectly parallel to
the well-developed saucer-shaped magmatic layering
in the host gabbros.
the upper part of MZ after the crystallisation of c.
70 % of the parental ferrobasalt magma. The Triple
Group is the name of a c. 100 m stratigraphy char-
acterised by three, distinct, leucogabbro layers. The
mineralisation is located in the stratigraphic section
from the base of the lower leucogabbro layer and to
just above the second leucogabbro layer. The miner-
alisation is composed of five main levels and in total
ten well-defined levels of enrichment in PGE (Pd-lev-
els). The stratigraphic separation between main Pd-
levels is c. 10 m. All Pd-levels are perfectly parallel to
the well-developed saucer-shaped magmatic layering
in the host gabbros.
The number of developed Pd-levels decreases
systematically toward the margins of the intrusion,
where only one Pd-level (Pd5) is developed. Gold is
where only one Pd-level (Pd5) is developed. Gold is
always concentrated in or just above the top of the
locally developed Pd-levels irrespective of the num-
ber of developed Pd-levels. The stratigraphic sepa-
ration between the base of Pd5 level and the top of
locally developed Pd-levels irrespective of the num-
ber of developed Pd-levels. The stratigraphic sepa-
ration between the base of Pd5 level and the top of
the Au-rich zones increases from c. 5 m at the mar-
gin to c. 60 m in the centre of the mineralistion.
gin to c. 60 m in the centre of the mineralistion.
The mineralisation has a low suphide content
(
<0.5 vol% bornite and chalcosite). the precious
metal grains occur in sulphide droplets in liquidus
metal grains occur in sulphide droplets in liquidus
minerals or groundmass or as free precious metal
droplets in the groundmass of the Ti-,V- and Fe-
rich host rock. The dominant PGE mineral is skaer-
gaardite (PdCu) in the centre of the intrusion, and
zviagintsevite (Pd3Pb) at the eastern margin. The
droplets in the groundmass of the Ti-,V- and Fe-
rich host rock. The dominant PGE mineral is skaer-
gaardite (PdCu) in the centre of the intrusion, and
zviagintsevite (Pd3Pb) at the eastern margin. The
gold mineralogy is more complex, but dominated
by tetraauricupride (AuCu).
by tetraauricupride (AuCu).
Inferred resource
The Skaergaard deposit is a PGE-Au-Ti-V-Fe multi
element mineralisation. The host rocks of the min-
eralisation are rich in titanium, vanadium and iron.
A 44-m profile across the mineralisations indicates
average contents of 6.6% TiO2, 1.3 kg/t V2O5 and
element mineralisation. The host rocks of the min-
eralisation are rich in titanium, vanadium and iron.
A 44-m profile across the mineralisations indicates
average contents of 6.6% TiO2, 1.3 kg/t V2O5 and
19% Fe2O3 in the host rock of the precious metal
mineralisation. The lowest Pd-level (Pd5) is the
main source of PGE and estimated to contain 104
million tonnes with of 0.11 g/t Au, 1.91 g/t Pd
and 0.16 g/t Pt. The combined gold zone is esti-
mated to contain 107 million tonnes with 1.68 g/t
Au, 0.59 g/t Pd and 0.05 g/t Pt.
million tonnes with of 0.11 g/t Au, 1.91 g/t Pd
and 0.16 g/t Pt. The combined gold zone is esti-
mated to contain 107 million tonnes with 1.68 g/t
Au, 0.59 g/t Pd and 0.05 g/t Pt.
Key references
Nielsen T.F.D. (2004). The shape and volume of the Skaergaard
intrusion: implications for mass balances and bulk compo-
sition. Journal of Petrology 45, 507530.
Nielsen, T.F.D., Andersen, J.C.Ø. & Brooks, C.K. (2005). The
Platinova Reef of the Skaergaard intrusion. Mineralogical
Association of Canada Short Course 35, 431455.
Wager, L. R. & Brown, G. M. (1968). Layered Igneous Rocks.
Edinburgh and London: Oliver & Boyd.
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
Author:
T.F.D. Nielsen
Editor: K.Secher
Layout: C.E. Thuesen, GEUS
© GEUS 2006
ISSN: 1602-8171
Precious metal phase in syn-magmatic sulphide droplet hosted in liquidus magnetite.
50 m
Last modified: March 3, 2006
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