Section 20
Chapter 19,046

Geology and trace-element geochemistry of the Umuna gold-silver deposit, Misima Island, Papua New Guinea

D.S.C.arke; R.W.L.wis; H.M.W.ldron

Journal of Geochemical Exploration 35(1-3): 201-223


ISSN/ISBN: 0375-6742
DOI: 10.1016/0375-6742(90)90039-d
Accession: 019045268

The Umuna epithermal gold-silver deposit on eastern Misima Island, P.N.G., is hosted within a 100–300-m-wide zone of fractures, veins, anastomosing shears, and breccia sheets recognized over a 3-km strike length. The host rocks to the deposit consist of a metamorphosed Cretaceous-Paleogene volcano-sedimentary sequence, extensively intruded by irregular Neogene granodioritic bodies. Vertical and lateral zonation is observed within the deposit. The geothermal system responsible for the mineralization is inferred to have a lateral extent similar to that of the present eastern portion of Misima Island: a number of gold occurrences peripheral to the deposit may be the result of localized enrichments in the distal parts of this system.

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