| dc.description.abstract | The Lundmark Akow area is located in the south-central porƟon of the South Rim assemblage of
the North Caribou Greenstone Belt. The mineralizaƟon consists of several base metal-bearing massive
sulphide horizons hosted in a sequence of garneƟferous staurolite mica schists in the southern porƟon of
the study area, to a northern host rock sequence dominated by volcanic and intrusive mafic to felsic
rocks. The igneous host rock porƟon of the study has been dated between 2973 to 2980 Ma through
zircon U/Pb geochronology. The meta-sedimentary sequence which hosts the mineralizaƟon is built
upon a basement of intrusive and volcanic rocks which formed in an oceanic plateau through plume
magmaƟsm before impinging upon a subducƟon zone. NegaƟve high field strength element (HFSE)
anomalies show that arc related magmaƟsm built upon the oceanic plateau. Sm/Nd isotope values from
the mafic to felsic volcanic and intrusive rocks show a spread in εNd from -1.53 to 3.07 suggesƟng that
melts were derived from both depleted mantle and plume sources, with some melts being contaminated
by an older crustal basement.
The characterisƟcs of the massive sulphide horizons, as well as the host meta-sedimentary rocks
are consistent with them having formed through distal VMS processes including hydrothermal
parƟculate fallout from buoyant plumes combined with pooling of dense sulphide-rich fluids in
topographic lows on the sea floor. The garnet-rich meta-sedimentary rocks show Fe and Mn enrichment
when normalized to immobile Al and Ti, consistent with addiƟon through hydrothermal plume
parƟculate processes. The characterisƟcs of the garnet layers suggest they formed through
metamorphism of a sediment derived from the intermixing of hydrothermal and terrigenous
parƟculates. The garnet composiƟons show prograde growth with a Mn- and Ca-rich core to a Fe- and
Mg-rich rim, supporƟng their formaƟon as a result of metamorphic condiƟons post exhalaƟve acƟvity. [...] | en_US |
