Sutarto, Sutarto and Arifudin, Arifudin and Sapto, Putranto and Agung, Harjoko and Lucas Donny, Setijadji (2013) MAGMATISM AND PORPHYRY Cu-Au MINERALISATION AT THE RANDU KUNING PROSPECT, SELOGIRI AREA, CENTRAL JAVA. Seminar Nasional Kebumian-VIII. pp. 316-329. ISSN 976-602-19765-2-4
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2013_Sutarto,et.al._MAGMATISM and PORPHYRY Cu-Au MINERALIZATION.pdf Download (1MB) | Preview |
Abstract
The Randu Kuning Porphyry Cu-Au prospect area is situated at Selogiri district, Wonogiri regency, Central Java, Indonesia, about 40 km to the south-east from Solo city, or approximately 70 km east of Yogyakarta city. The Randu Kuning area and its vicinity is a part of the East Java Southern Mountain Zone, mostly occupied by both plutonic and volcanic igneous rocks, volcaniclastic rocks, silisiclastic rocks and also carbonate rocks. Magmatism-volcanism products at Selogiri area were indicated by the abundant of igneous rocks and volcaniclastic rocks of Mandalika and Semilir Formation and many dioritic intrusive rocks as part of the Late Eocene-Early Miocene magmatism. Porphyry Cu-Au mineralisation at Randu Kuning Prospect have strong genetic correlation with the Tertiary magmatism-volcanism processes. Three types of dioritic-andesitic intrusive rocks at the Randu Kuning Prospect, include hornblende-pyroxene diorite, horblende microdiorite, and quartz diorite are distributed at the centre of a half-circular depression on approximately 8 km in diameter is thought to be a feeder of an ancient volcanic crater. Porphyry Cu-Au mineralisation at the area related with the hornblende microdiorite intrusion process. The alteration type at the Randu Kuning area and its vicinity can be divided into several zones of hydrothermal alteration, such as the potassic zone (magnetite-biotite-K feldspar), prophyllitic zone (chlorite-magnetite-epidote-carbonate), phyllic zone (quartz-sericite-chlorite) and argillic zones (clay mineral-sericite). The alteration pattern in the Randu Kuning porphyry Cu-Au deposit is tipically a diorite model which characterized by the domination of potassic alteration zone on the inside and propylitic type on the outside. Phyllic and argillic alteration type sometimes appear, although with a small volume commontly associated with the presence of fault zones. At least two mineralization style recognised at the Randu Kuning area i.e.Cu-Au disseminated mineralization, mostly occured associated with the present of chalcopyrite-pyrite dissemination within magnetite-actinolite-epidote±chlorite alteration (inner prophyllitic) and Cu-Au quartz-sulphide vein mineralization, including quartz-chalcopyrite veins, chalcopyrite-pyrite veins and pyrite-chalcopyrite-sphalerite-carboate veins. Quarzt-sulphide veins mostly associated within the potassic and argillic alteration zone, but a few quartz veins also were found within prophyllitic zone. Key words: magmatism, hydrothermal, Cu-Au mineralisation
| Item Type: | Article |
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| Subjects: | Q Science > QE Geology |
| Divisions: | Faculty of Engineering, Science and Mathematics > School of Engineering Sciences |
| Depositing User: | Dr.Ir SUTARTO - |
| Date Deposited: | 22 Jan 2019 07:33 |
| Last Modified: | 22 Jan 2019 07:33 |
| URI: | http://eprints.upnyk.ac.id/id/eprint/18086 |
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