The Nemeiben Lake ultramafic body is located in the center of Saskatchewan, Canada, within the Churchill Province of the Canadian Shield. The ultramafic rocks consist of serpentinites, partly serpentinized and uralitized pyroxenite, and unaltered pyroxenite. Associated sulphide mineralization is of disseminated, net texture, and fracture filling types. The ore minerals present are pyrrhotite, pentlandite, chalcopyrite, pyrite, marcasite, violarite, bravoite and native copper. The sulphides are considered to be initially of magmatic origin formed from a sulphide melt separated at a late stage during crystallization of the ultramafic rocks. Subsequent serpentinization has locally redistributed the ores.
Serpentinization in the Nemeiben Lake ultramafic rocks was accompanied by introduction-of water with no apparent changes of SiO2 and MgO contents. A minor removal of CaO and possible addition of sulfur during serpentinization is the only apparent chemical change.
From investigation of co-existing clinopyroxenes, orthopyroxene and olivine and the distribution of Mg and Fe between pyroxenes, it appears that the Nemeiben Lake ultramafic body crystallized at high temperature between 1100-1200 ºC and in a pressure range between 5-9 Kb.
Peddada, A., 1972. Petrology of the Nemeiben Lake Ultramafic and
Associated Nickel-Sulphide Deposits.
Unpublished MSc. thesis, State University of New York at Albany. 166pp., +xi.
University at Albany Science Library call number: SCIENCE Oversize (*) QE 461 P43X
thesis (scanned text) - 13.4MB pdf file
Figure 2 - Geological
map of the Nemeiben Lake Ultramafic body, Saskatchewan
coloured geological outcrop map (scale 1:8400) - 1MB pdf file
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