|
|
|||||||||||||||||||||||
|
||||||||||||||||||||||||
Theme Magazines and Fact Sheets
EXPLORATION AND MINING IN GREENLANDGreenland Mineral Resources
Fact Sheet No. 14
Download pdf-file go_fs14.pdf (~230 kbyte). Requires pdf-reader, Acrobat GSview or similar
Significant concentrations of stratabound barite
and celestite are hosted by the Upper Permian
carbonate sequences of central East Greenland.
During exploration by Nordisk Mineselskab A/S
195284, these minerals were used as pathfinders
for base metal mineralisation. The low market
price for sulphates of barium and strontium was
the reason why they never constituted economic
targets in their own right.
and celestite are hosted by the Upper Permian
carbonate sequences of central East Greenland.
During exploration by Nordisk Mineselskab A/S
195284, these minerals were used as pathfinders
for base metal mineralisation. The low market
price for sulphates of barium and strontium was
the reason why they never constituted economic
targets in their own right.
Geological setting
Following denudation of the Caledonian fold belt, epi-
continental rift basins developed along the east coast of
Greenland in which Upper Permian shallow marine sedi-
ments were deposited. The stratabound barite and celes-
tite occur in the Jameson Land Basin that covers approx.
13,000 km
continental rift basins developed along the east coast of
Greenland in which Upper Permian shallow marine sedi-
ments were deposited. The stratabound barite and celes-
tite occur in the Jameson Land Basin that covers approx.
13,000 km
2
. The Upper Permian Foldvik Creek Group
rests with angular unconformity on Devonian to Lower
Permian continental clastic sediments being overlain
conformably by Triassic to Cretaceous, mainly marine
clastic sediments. Tertiary igneous rocks intrude this suc-
cession. The c. 300 m thick Upper Permian sequence
comprises a basal conglomerate, marginal marine evap-
orites and carbonates (Karstryggen and Wegener Halvø
Formations), bituminous shale and a shallow marine
clastic unit. Stratabound copper-lead-zinc mineralisation
is common in the Upper Permian and Triassic sediments.
Permian continental clastic sediments being overlain
conformably by Triassic to Cretaceous, mainly marine
clastic sediments. Tertiary igneous rocks intrude this suc-
cession. The c. 300 m thick Upper Permian sequence
comprises a basal conglomerate, marginal marine evap-
orites and carbonates (Karstryggen and Wegener Halvø
Formations), bituminous shale and a shallow marine
clastic unit. Stratabound copper-lead-zinc mineralisation
is common in the Upper Permian and Triassic sediments.
Barite
The most significant barite occurrences are in the western
part of the Jameson Land Basin in a specific strata level
at the base of the Karstryggen Formation. They are in-
variably associated with steep 160°180°-trending faults
hosting sulphide-bearing quartz-barite veins. The strata-
bound barite is typically developed as `zebra' barite, i.e.
a rhythmically banded deposit consisting of mm-cm
thick, alternating white and grey bands that resembles
bedding, even cross-bedding. The white bands are pure
barite; the grey bands are a mixture of barite and fine-
grained dolomite and calcite. Varying amounts of
quartz and lead-zinc sulphides accompany the barite.
The massive `zebra' barite typically contains 8090%
barite. The `zebra' barite is considered to be formed by
selective replacement of a porous limestone/evaporate
unit. The zones of replacement form 210 m thick and
150200 m wide belts along the 160°180°-trending
faults, which probably acted as feeders. As the feeder
veins have not been observed in rocks younger than
Upper Permian, a late Permian age is assumed for both
the veins and the stratabound mineralisation.
part of the Jameson Land Basin in a specific strata level
at the base of the Karstryggen Formation. They are in-
variably associated with steep 160°180°-trending faults
hosting sulphide-bearing quartz-barite veins. The strata-
bound barite is typically developed as `zebra' barite, i.e.
a rhythmically banded deposit consisting of mm-cm
thick, alternating white and grey bands that resembles
bedding, even cross-bedding. The white bands are pure
barite; the grey bands are a mixture of barite and fine-
grained dolomite and calcite. Varying amounts of
quartz and lead-zinc sulphides accompany the barite.
The massive `zebra' barite typically contains 8090%
barite. The `zebra' barite is considered to be formed by
selective replacement of a porous limestone/evaporate
unit. The zones of replacement form 210 m thick and
150200 m wide belts along the 160°180°-trending
faults, which probably acted as feeders. As the feeder
veins have not been observed in rocks younger than
Upper Permian, a late Permian age is assumed for both
the veins and the stratabound mineralisation.
Bredehorn
At Bredehorn, stratabound barite-lead-zinc mineralisa-
tion occurs within a c. 1 km
At Bredehorn, stratabound barite-lead-zinc mineralisa-
tion occurs within a c. 1 km
2
fault-bounded area that
also hosts galena-sphalerite-bearing quartz-barite veins.
The area has a profuse talus cover and the mineralisation
is only well exposed in a steep cliff, Zebra Klint, where an
810 m thick `zebra' barite unit is exposed over 300 m.
This is massive in the middle part with transition zones
of limestone/barite beds in the upper and lower parts.
The barite beds display apparent sedimentary structures
and they host silicified parts, as well as 24% galena
and sphalerite as disseminations and massive lenses. A
NS-striking barite-quartz vein exposed in the cliff far-
ther north is believed to represent a feeder. A resource
of 300,000 tons with 72% barite has been estimated
by chip sampling near the cliff, but the area is believed
to host in total several million tons of barite, as well as
considerable lead-zinc tonnage.
The area has a profuse talus cover and the mineralisation
is only well exposed in a steep cliff, Zebra Klint, where an
810 m thick `zebra' barite unit is exposed over 300 m.
This is massive in the middle part with transition zones
of limestone/barite beds in the upper and lower parts.
The barite beds display apparent sedimentary structures
and they host silicified parts, as well as 24% galena
and sphalerite as disseminations and massive lenses. A
NS-striking barite-quartz vein exposed in the cliff far-
ther north is believed to represent a feeder. A resource
of 300,000 tons with 72% barite has been estimated
by chip sampling near the cliff, but the area is believed
to host in total several million tons of barite, as well as
considerable lead-zinc tonnage.
Oksedal
Along a NNW-striking quartz-barite vein in Oksedal, the
lower 59 m of the poorly exposed Upper Permian lime-
stone is replaced by `zebra' barite up to 150 m from the
vein. Lead and zinc contents are negligible. A resource of
Along a NNW-striking quartz-barite vein in Oksedal, the
lower 59 m of the poorly exposed Upper Permian lime-
stone is replaced by `zebra' barite up to 150 m from the
vein. Lead and zinc contents are negligible. A resource of
Barite and celestite in
central East Greenland
central East Greenland
Fact Sheet
No. 14
Greenland
Mineral
Resources
No. 14
Greenland
Mineral
Resources
22°
24°
22°
72°
72°
Scoresby
Sund
Jameson
Land
Wegener Halvø
Mesters
Vig
1
2
3
5
4
Fault
Tertiary intrusives
Cretaceous
Jurassic
Triassic
Upper Permian
Carboniferous
Devonian
Pre-Devonian
25 km
Geological map of the Jameson Land Basin showing main local-
ities for barite (14) and celestite (5). 1. Triaskæden, 2. Oksedal,
3. Bredehorn, 4. Devondal, 5. Karstryggen.
ities for barite (14) and celestite (5). 1. Triaskæden, 2. Oksedal,
3. Bredehorn, 4. Devondal, 5. Karstryggen.
some 330,000 tons with 9095% barite has been
indicated in a shallow sub-surface by a few drill
holes.
indicated in a shallow sub-surface by a few drill
holes.
Triaskæden
At Triaskæden, Upper Permian limestones are bari-
tised and silicified adjacent to a NS-striking quartz-
barite vein. A more than 3 m thick sequence of
barite-bearing rocks can be followed laterally for c.
200 m on a scree slope. The barite-bearing rocks
are mainly `zebra' barite and limestones with ran-
domly orientated barite crystals and minor dissemi-
nated galena.
At Triaskæden, Upper Permian limestones are bari-
tised and silicified adjacent to a NS-striking quartz-
barite vein. A more than 3 m thick sequence of
barite-bearing rocks can be followed laterally for c.
200 m on a scree slope. The barite-bearing rocks
are mainly `zebra' barite and limestones with ran-
domly orientated barite crystals and minor dissemi-
nated galena.
Devondal
On Wegener Halvø in the eastern part of the Jameson
Land Basin, the Foldvik Creek Group is dominated
by a c. 250 m thick carbonate sequence. Scattered
barite veins occur in the top of the Wegener Halvø
Formation throughout the peninsula but the largest
concentrations exist on the north side of Devondal.
Here a mainly concordant, c. 4 m thick quartz-
barite-sulphide unit occurs over c. 1 km
On Wegener Halvø in the eastern part of the Jameson
Land Basin, the Foldvik Creek Group is dominated
by a c. 250 m thick carbonate sequence. Scattered
barite veins occur in the top of the Wegener Halvø
Formation throughout the peninsula but the largest
concentrations exist on the north side of Devondal.
Here a mainly concordant, c. 4 m thick quartz-
barite-sulphide unit occurs over c. 1 km
2
in the
contact between reefy limestone and bedded sandy
limestone. This unit contains an estimated 55%
quartz, 40% barite and 24% sulphides.
limestone. This unit contains an estimated 55%
quartz, 40% barite and 24% sulphides.
Celestite
Celestite mineralisation occurs in the Karstryggen
Formation over 80 km
Formation over 80 km
2
of the Karstryggen plateau.
It appears both in a lower 310 m thick algal-lami-
nated limestone-evaporite unit where up to 80% of
the calcite and gypsum can be replaced by celestite,
and in an overlying c. 50 m thick karst breccia
sequence. This occurs typically as large-scale vein-
ing superimposed on an intense small-scale vein-
ing and breccia filling. It is assumed that the celes-
tite was formed by early diagenetic replacement of
gypsum in the algal-laminated limestone during
interaction with Sr-enriched terrestrial ground water.
nated limestone-evaporite unit where up to 80% of
the calcite and gypsum can be replaced by celestite,
and in an overlying c. 50 m thick karst breccia
sequence. This occurs typically as large-scale vein-
ing superimposed on an intense small-scale vein-
ing and breccia filling. It is assumed that the celes-
tite was formed by early diagenetic replacement of
gypsum in the algal-laminated limestone during
interaction with Sr-enriched terrestrial ground water.
Based on scattered chip sampled sections, a re-
source of 2550 million tons with c. 50% celestite
has been estimated for a 4 km
source of 2550 million tons with c. 50% celestite
has been estimated for a 4 km
2
area. The total
resources at Karstryggen are much larger.
Concluding remarks
Due to low prices and often inaccessible locations,
the barite and celestite occurrences seem to be of
no immediate economic interest. Among the barite
showings, Oksedal is the most attractive because of
its accessibility from the coast, a gentle topography
and the near absence of quartz and sulphides. It
could be a useful source for drilling mud during
local drilling after other commodities. The very
large celestite occurrences belong to the future.
the barite and celestite occurrences seem to be of
no immediate economic interest. Among the barite
showings, Oksedal is the most attractive because of
its accessibility from the coast, a gentle topography
and the near absence of quartz and sulphides. It
could be a useful source for drilling mud during
local drilling after other commodities. The very
large celestite occurrences belong to the future.
Key references
Harpøth, O., Pedersen, J.L., Schønwandt, H.K. & Thomassen,
B. 1986:
The mineral occurrences of central East Greenland.
Meddelelser om Grønland, Geoscience
17
, 139 pp.
Paar, W. 1974:
Die Gefüge der synsedimentär-syndiagenetis-
chen Schwerspat-Bleiglanz-Lagerstätte "Breithorn", Ost-
grönland. Archiv für Lagerstättenforschung in den Ostalpen,
Sonderband
2
, 216237.
Scholle, P.A., Stemmerik, L. & Harpøth, O. 1990:
Origin of
major karst-associated celestite mineralization in Karstryggen,
central East Greenland. Journal of Sedimentary Petrology
60
, 397410.
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
B. Thomassen, GEUS
Editor
K. Secher, GEUS
Layout
C.E. Thuesen, GEUS
Photographs
GEUS unless otherwise stated
Printed
January 2007 © GEUS
Printers
Schultz Grafisk
ISSN
1602-8171
`Zebra' barite at Zebra Klint,
Bredehorn.
Bredehorn.
Celestite crystals at Karstryggen.
Last modified: January 23, 2007
|
