Exploration geochemistry
The philosophy behind the use of stream sediment in
mineral exploration is that weathering products from
mineral deposits exposed at the surface will be trans-
ported downhill and deposited in streams. Elevated con-
centrations of the ore metal(s) in systematically collected
stream sediment samples will therefore often be indica-
tive of mineralisation.
Exploration geochemistry is an obvious discipline to
conduct in the process of prospecting for new mineral
resources. The data acquired during such surveys may
also be used for geological mapping and modelling and
environmental studies. The `Geochemical atlas of
Greenland West and South Greenland' is based on
compilation of chemical analyses of stream sediment
samples collected from 1977 to 1998 in surveys under-
taken by the Geological Survey of Denmark and Green-
land.
Use of regional geochemical data
The geochemical data set for West and South Green-
land quantifies geochemical differences between rock
complexes of different age and geological setting.
Accordingly the data set is a documentation of the na-
tural geochemical background over a large area. The
geochemical maps within the atlas demonstrate, for the
first time, the magnitude of the considerable natural
variation in the concentration of chemical elements that
exists over the selected area. This recognition has
specific implications for mineral resource assessment in
Greenland.
Stream sediment sampling
Stream sediments have been selected as sample me-
dium for geochemical exploration in Greenland. The
mountainous terrain together with melting snow and
ice has created well-developed stream systems, and,
contrary to soil or vegetation, streams are ubiquitous in
Greenland. The sampling density has varied, but large
parts of West Greenland have been sampled at recon-
naissance scale, i.e. one sample per 20 to 40 km
2
.
At each sampling site c. 500 g of stream sediment was
collected. The sample was generally composed of sub-
samples from three to fifteen sediment deposits along
10 to 50 m of the stream course.
Chemical analysis
Sampling and sample preparation have followed the
standard procedures throughout the period of the sur-
vey. Analytical treatment has been less systematic,
mainly because of progress in analytical methodology.
Almost all samples have been analysed for major ele-
ments by XRF and for trace elements by INA. By con-
trast, trace element analysis by XRF, AAS and ICP-ES,
have not been carried out for all samples.
Geochemical data as
exploration tools in West and
South Greenland
Greenland Mineral Resources
Fact Sheet No. 4
The final data set comprises a total of 7122 sam-
ples, analysed for up to 43 elements. Chemical
data from individual surveys were intercalibrated
by means of reference material to eliminate analyt-
ical bias.
Element distribution maps
Each map sheet displays a contoured grid image
of the variation in element concentration, a colour
scale giving class intervals for the grid colours, and
statistical information.
Mineral resource assessment
The use of the atlas data to identify high values,
anomalies, is straightforward and is facilitated by
showing the location of anomalies on the atlas
maps. Several of these element anomalies are, in
fact, located near known mineral occurrences con-
taining the element in question, while others are
located in areas where mineralisation is presently
unknown. The latter category is particularly inter-
esting to exploration companies and merits further
investigation.
A more indirect way of using the data, is to identi-
fy geological environments with a high potential
for formation of ore deposits. These environments,
e.g. volcanic arcs, marine shales along escarp-
ments and alkaline intrusions, may be identified
using their geochemical signature together with
information on structure, age, tectonic setting etc.
For example, sedimentary sequences enriched in
arsenic are considered a favourable source envi-
ronment for gold deposits, and the high-arsenic
regions in West and South Greenland are clearly
outlined by the map of arsenic. The map of gold
confirms the location of gold anomalies within the
arsenic provinces, but also suggests that gold min-
eralisation, unrelated to arsenic, has taken place.
The geochemical data set behind the atlas is available
at cost from GEUS.
Greenland Resources A/S
Vandsøvej 5
P.O. Box 821
DK-3900 Nuuk
Greenland
Tel: (+299) 32 79 13
Fax.: (+299) 32 79 14
E-mail: gras@greennet.gl
Internet: www.resources.gl
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:
A. Steenfelt
Editor: K.Secher
Layout: GEUS, Grafisk
© GEUS 2003
Key references
Schjøth, F., Garde, A.A., Jørgensen, M.S., Lind, M., Moberg, E.,
Nielsen, T.F.D., Rasmussen, T.M., Secher, K., Steenfelt, A.,
Stendal, H., Thorning, L. & Tukiainen, T. 2000: Mineral resource
potential of South Greenland: the CD-ROM. Thematic map-
data on CD-ROM. Danmarks og Grønlands Geologiske
Undersøgelse 2000/57, 36 pp. 1 CD-ROM included.
Steenfelt, A. 1999: Compilation of data sets for a geochemical
atlas of West and South Greenland based on stream sedi-
ment surveys 1977 to 1997. Danmarks og Grønlands
Geologiske Undersøgelse Rapport 1999/41, 33 pp.
Steenfelt, A. 2001: Calibration of stream sediment data from West
and South Greenland. A supplement to GEUS report 1999/41.
Danmarks og Grønlands Geologelse Rapport 2001/47. 43 pp.
Steenfelt, A. 2001: Geochemical atlas of Greenland West and
South Greenland, Danmarks og Grønlands Geologiske
Undersøgelse Rapport 2001/46, 40 pp.
Major elements
Si
Ti
Al
Fe
Mn
Mg
Ca
Na
K
As
Au
Ba
Br
Ce
Co
Cr
Cs
Cu
Eu
Trace elements
Ga
Hf
La
Lu
Mo
Nb
Nd
Ni
Rb
Sb
Sc
Sm
Sr
Ta
Tb
P
Th
U
V
W
Y
Yb
Zn
Zr
