Petrogenesis of Ni-sulfide mineralisation in the ca. 3.0 Ga Maniitsoq intrusive belt, western Greenland
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Petrogenesis of Ni-sulfide mineralisation in the ca. 3.0 Ga Maniitsoq intrusive belt, western Greenland. / Maier, Wolfgang D.; Muir, D. D.; Barnes, S.- J.; Szilas, K.
In: Mineralium Deposita, 2024.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Petrogenesis of Ni-sulfide mineralisation in the ca. 3.0 Ga Maniitsoq intrusive belt, western Greenland
AU - Maier, Wolfgang D.
AU - Muir, D. D.
AU - Barnes, S.- J.
AU - Szilas, K.
N1 - Publisher Copyright: © The Author(s) 2024.
PY - 2024
Y1 - 2024
N2 - The ca. 3.0 Ga Ni sulfide mineralisation at Maniitsoq, SW Greenland, is hosted by a cluster of relatively small, irregularly shaped mafic-ultramafic intrusions, typically 10s of m to a few km across, that are lodged within broadly coeval gneiss. Many of the intrusions are fault bounded and fragmented so that their original sizes remain unknown. The sulfides form disseminations and sulfide matrix breccia veins displaying sharp contacts to the host intrusives. The mineralisation has relatively high Ni/Cu, with 4–10% Ni and 1–2% Cu. Correlations between Ni and Cu with sulfide content are strong, consistent with a magmatic origin of the mineralisation. PGE contents are mostly below 0.5 ppm, and Cu/Pd is typically above primitive mantle levels, interpreted to reflect equilibration of the parent magma with segregating sulfide melt prior to final magma emplacement. Sulfide segregation was likely triggered by assimilation of crustal sulfur, as suggested by whole rock S/Se ratios of 7000–9000. The sulfide melt underwent extensive fractionation after final emplacement, caused by downward percolation of Cu-rich sulfide melt through incompletely solidified cumulates. We suggest that the exposed Maniitsoq intrusions represent the Ni-rich upper portions of magma conduits implying that there is potential for Cu-rich sulfides in unexposed deeper portions of the belt.
AB - The ca. 3.0 Ga Ni sulfide mineralisation at Maniitsoq, SW Greenland, is hosted by a cluster of relatively small, irregularly shaped mafic-ultramafic intrusions, typically 10s of m to a few km across, that are lodged within broadly coeval gneiss. Many of the intrusions are fault bounded and fragmented so that their original sizes remain unknown. The sulfides form disseminations and sulfide matrix breccia veins displaying sharp contacts to the host intrusives. The mineralisation has relatively high Ni/Cu, with 4–10% Ni and 1–2% Cu. Correlations between Ni and Cu with sulfide content are strong, consistent with a magmatic origin of the mineralisation. PGE contents are mostly below 0.5 ppm, and Cu/Pd is typically above primitive mantle levels, interpreted to reflect equilibration of the parent magma with segregating sulfide melt prior to final magma emplacement. Sulfide segregation was likely triggered by assimilation of crustal sulfur, as suggested by whole rock S/Se ratios of 7000–9000. The sulfide melt underwent extensive fractionation after final emplacement, caused by downward percolation of Cu-rich sulfide melt through incompletely solidified cumulates. We suggest that the exposed Maniitsoq intrusions represent the Ni-rich upper portions of magma conduits implying that there is potential for Cu-rich sulfides in unexposed deeper portions of the belt.
KW - Archean ore deposits
KW - Greenland
KW - Magma conduit
KW - Nickel sulfides
U2 - 10.1007/s00126-024-01282-3
DO - 10.1007/s00126-024-01282-3
M3 - Journal article
AN - SCOPUS:85195630615
JO - Mineralium Deposita
JF - Mineralium Deposita
SN - 0026-4598
ER -
ID: 395511619