Abstract
The primary source of the alluvial platinum-group minerals (PGM) of the Freetown Layered Intrusion, Sierra Leone, has been unknown since their discovery 70 years ago. This is a report on work in progress to establish a primary occurrence related to the igneous layering. New whole-rock major and minor element analyses and precious metal assays show that at key horizons there is a significant change in the silicate mineral compositions and in Cu, Cr and Ni, as well as in Pt and Pd, comparable to those encountered in other PGM-bearing layered intrusions. Anomalous (0.1 to 0.4 g/t) Pt levels occur in pyroxene troctolites, which maintain these levels along strike.
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Received: 30 July 1999 / Accepted: 2 December 1999
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Bowles, J. A primary platinum occurrence in the Freetown Layered Intrusion, Sierra Leone. Mineral. Deposita 35, 583–586 (2000). https://doi.org/10.1007/s001260050263
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DOI: https://doi.org/10.1007/s001260050263