The PGE potential in Greenland - Geus
The PGE potential in Greenland - Geus
The PGE potential in Greenland - Geus
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GEOLOGY AND ORE 8 / 2007<br />
<strong>The</strong> <strong>PGE</strong> <strong>potential</strong><br />
<strong>in</strong> <strong>Greenland</strong><br />
<strong>The</strong> <strong>potential</strong> for Plat<strong>in</strong>um Group Element<br />
(<strong>PGE</strong>) resources <strong>in</strong> <strong>Greenland</strong> is<br />
clear and encompasses m<strong>in</strong>eralisation<br />
<strong>in</strong> Precambrian to Palaeogene environments.<br />
<strong>The</strong> <strong>PGE</strong> <strong>potential</strong> <strong>in</strong> <strong>Greenland</strong><br />
attracted <strong>in</strong>terest already <strong>in</strong> the<br />
1960s and has been part of the Survey’s<br />
considerations s<strong>in</strong>ce the 1970s .<br />
<strong>The</strong> corporate <strong>in</strong>terest <strong>in</strong> <strong>PGE</strong> targets<br />
<strong>in</strong> <strong>Greenland</strong> was <strong>in</strong>itiated by<br />
Kryolitselskabet Øresund <strong>in</strong> the early<br />
1960s and was related to a suite of<br />
norites <strong>in</strong> West <strong>Greenland</strong>. Plat<strong>in</strong>om<strong>in</strong>o<br />
A/S was established <strong>in</strong> 1968 to search<br />
for Merensky Reef type deposits <strong>in</strong><br />
the Fiskenæsset Complex. In the late<br />
1980s, Plat<strong>in</strong>ova Resources prospected<br />
known <strong>PGE</strong> <strong>in</strong>dications <strong>in</strong> Amitsoq peridotites<br />
<strong>in</strong> southern <strong>Greenland</strong>. S<strong>in</strong>ce<br />
1995 norites <strong>in</strong> the Tasiilaq region,<br />
East <strong>Greenland</strong> have been the target<br />
for Cu-Ni-<strong>PGE</strong> exploration by several<br />
companies. In 2005 NunaM<strong>in</strong>erals <strong>in</strong>itiated<br />
<strong>PGE</strong> exploration <strong>in</strong> the mafic<br />
<strong>in</strong>trusions of the Fiskefjord area. In<br />
the 1980s GEUS and university groups<br />
focused on the formation of massive<br />
sulphides <strong>in</strong> the Palaeogene basalts of<br />
Disko Island, which has led to cont<strong>in</strong>ued<br />
exploration for Noril´sk type m<strong>in</strong>eralisations.<br />
Renewed academic studies<br />
and exploration by Plat<strong>in</strong>ova<br />
Resources <strong>in</strong> the classic Skaergaard<br />
<strong>in</strong>trusion (East <strong>Greenland</strong>) resulted <strong>in</strong><br />
1987 <strong>in</strong> the discovery of a reef-type,<br />
world class <strong>PGE</strong> deposit.<br />
Geological environment<br />
for <strong>PGE</strong>s<br />
Traces and show<strong>in</strong>gs of <strong>PGE</strong> m<strong>in</strong>eralisation<br />
are numerous <strong>in</strong> the Precambrian terra<strong>in</strong>s<br />
of <strong>Greenland</strong>. <strong>The</strong> Archaean of south-west<br />
<strong>Greenland</strong> hosts anorthositic suites, like<br />
the reworked Fiskenæsset complex (south<br />
of Nuuk). <strong>The</strong> complex hosts accumulation<br />
of chromite <strong>in</strong> anorthosite, and traces of<br />
<strong>PGE</strong> m<strong>in</strong>eralisation <strong>in</strong> Ni-sulphide segregations<br />
<strong>in</strong> amphibolite. <strong>The</strong> Archaean shield<br />
north of Nuuk hosts the Maniitsoq Norite<br />
Hammer Dal<br />
Disko<br />
Kangerlussuaq/<br />
Skaergaard<br />
Sillisissanguit<br />
Fiskefjord<br />
Nunaat<br />
Tasiilaq<br />
Qeqertarsuatsiaat<br />
(Fiskenæsset)<br />
Amitsoq<br />
Belt; a suite of leuconorite and gabbro rocks<br />
<strong>in</strong> irregular bodies with traces of <strong>PGE</strong>s related<br />
to Ni-Cu-sulphide m<strong>in</strong>eralisation.<br />
With<strong>in</strong> the same region, large ultramafic<br />
bodies and mafic layered complexes locally<br />
show traces of <strong>PGE</strong>-m<strong>in</strong>eralisation. <strong>The</strong><br />
Proteroizoic Ammassalik Belt on the East<br />
coast of <strong>Greenland</strong> hosts a suite of norites<br />
to which are related massive sulphide occurrences,<br />
<strong>potential</strong>ly <strong>PGE</strong>-bear<strong>in</strong>g.<br />
Palaeogene Ni-sulphide occurrences with<br />
<strong>potential</strong> <strong>PGE</strong> concentrations are known <strong>in</strong><br />
the West <strong>Greenland</strong> Basalt Prov<strong>in</strong>ce. Exploration<br />
has been carried out for more<br />
than a century <strong>in</strong> the Disko Bay region.<br />
Known occurrences are ma<strong>in</strong>ly hosted <strong>in</strong><br />
presumably contam<strong>in</strong>ated lavas, and <strong>in</strong><br />
dykes at the base of the volcanic succession.<br />
Only reconnaissance <strong>in</strong>vestigations<br />
have been performed <strong>in</strong> similar environments<br />
<strong>in</strong> East <strong>Greenland</strong>.<br />
<strong>The</strong> ma<strong>in</strong> focus of <strong>PGE</strong> exploration <strong>in</strong><br />
the Palaeogene of East <strong>Greenland</strong> has been<br />
the layered mafic <strong>in</strong>trusions <strong>in</strong> which many<br />
m<strong>in</strong>eralisations have been located, <strong>in</strong>clud<strong>in</strong>g<br />
the Kap Edvard Holm complex and the<br />
world class Plat<strong>in</strong>ova Reef with<strong>in</strong> the Skaergaard<br />
<strong>in</strong>trusion.<br />
Index map of localities on <strong>Greenland</strong>.<br />
Archaean and Palaeoproterozoic<br />
sett<strong>in</strong>gs<br />
Fiskenæsset anorthosite complex:<br />
Chromitite layered anorthosite <strong>in</strong>trusion.<br />
<strong>The</strong> Archaean Fiskenæsset anorthosite complex,<br />
with a strike length of > 200 km, is<br />
hosted <strong>in</strong> high grade tonalitic gneiss. <strong>The</strong><br />
complex is named after the village Fiskenæsset/Qeqertarsuatsiaat.<br />
<strong>The</strong> floor of the<br />
<strong>in</strong>trusion has not been identified, but the<br />
roof found immediately below flows of<br />
mafic pillow lava. A detailed stratigraphy<br />
shows a succession with a lower gabbro<br />
unit followed by an ultramafic unit with<br />
m<strong>in</strong>eral-graded dunites, peridotites and<br />
hornblendites. <strong>The</strong>se are followed by a<br />
lower leucograbbro unit with m<strong>in</strong>or ultramafic<br />
layers and a middle gabbro unit<br />
with m<strong>in</strong>or layers of anorthosite and ultramafics<br />
and peridotites (hornblende-orthopyroxene-sp<strong>in</strong>el).<br />
Above these units follow<br />
the upper leucogabbro unit with abundant<br />
chromitite bands, an anorthosite unit and<br />
the upper gabbro unit. <strong>The</strong> complex has<br />
been repeatedly deformed and metamor-<br />
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