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
1990
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.