Placer and lode platinum-group minerals in South Kalimantan, Indonesia: Evidence for derivation from Alaskan-type ultramafic intrusions
Titel:
Placer and lode platinum-group minerals in South Kalimantan, Indonesia: Evidence for derivation from Alaskan-type ultramafic intrusions
Auteur:
Zientek, M. L. Pardiarto, B. Simandjuntak, H. R. W. Wikrama, A. Oscarson, R. L. Meier, A. L. Carlson, R. R.
Verschenen in:
Australian journal of earth sciences
Paginering:
Jaargang 39 (1992) nr. 3 pagina's 405-417
Jaar:
1992-07
Inhoud:
Platinum-group element minerals (PGM) occur in significant proportions in placer deposits in several localities in South Kalimantan. They consist of Pt-Fe alloy that may be intergrown with or contain inclusions of Ir-Os-Ru alloy, laurite and chromite. Alluvial PGM found along Sungai Tambanio are in part derived from chromitite schlieren in dunitic bodies intruded into clinopyroxene cumulates that may be part of an Alaskan-type ultramafic complex. A chromitite schlieren in serpentinite from one of these dunitic bodies is anomalous in PGE (Pt: 580 ppb; Pd: 3.4 ppb; Rh: 1 ppb; Ru: 9 ppb; Ir: 21 ppb; and Os: 3.9 ppb). The chondrite-normalized PGE pattern for this rock, pan concentrates from this area, and PGM concentrates from diamond-Au-PGM placer deposits have an 'M'-shaped pattern enriched in Ir and Pt that is typical of PGE-mineralization associated with Alaskan-type ultramafic complexes.