VEINS AND HYDROTHERMAL BRECCIAS OF THE RANDU KUNING PORPHYRY Cu-Au AND EPITHERMAL Au DEPOSITS AT SELOGIRI AREA, CENTRAL JAVA INDONESIA

Sutarto Sutarto; Arifudin Idrus; Agung Harijoko; Lucas Donny Setijadji; Franz Michael Meyer

doi:10.22146/jag.26982

VEINS AND HYDROTHERMAL BRECCIAS OF THE RANDU KUNING PORPHYRY Cu-Au AND EPITHERMAL Au DEPOSITS AT SELOGIRI AREA, CENTRAL JAVA INDONESIA

https://doi.org/10.22146/jag.26982

Sutarto Sutarto^(1*), Arifudin Idrus⁽²⁾, Agung Harijoko⁽³⁾, Lucas Donny Setijadji⁽⁴⁾, Franz Michael Meyer⁽⁵⁾

(1) Universitas Pembangunan Nasional ”Veteran
(2) Geological Engineering Department, Faculty of Engineering, Gadjah Mada University
(3) Geological Engineering Department, Faculty of Engineering, Gadjah Mada University
(4) Geological Engineering Department, Faculty of Engineering, Gadjah Mada University
(5) RWTH Aachen University, Germany
(*) Corresponding Author

Abstract

The Randu Kuning prospect is situated at Selogiri area, Wonogiri, Central Java, Indonesia. This location is about 40 km to the south-east from Solo city or approximately 70 km east of Yogyakarta city. Many Tertiary dioritic rocks related alterationmineralisation were found at the Randu Kuning area and its vicinity, including hornblende microdiorite, hornblende-pyroxene diorite and quartz diorite. Mineralisation type of the Randu Kuning prospect was interpreted as porphyry Cu-Au and a number epithermal Au-base metals deposits in its surrounding. The closed existing of porphyry Cu-Au and epithermal Au-base metals type deposits at the Randu Kuning area produced a very complex of veins and hydrothermal breccias crosscutting relationship. A lot of porphyry veins types were found and observed at the Randu Kuning area, and classiﬁed into at least seven types. Most of the porphyry veins were cross cut by epithermal type veins. Many epithermal veins also are found and crosscut into deeply porphyry vein types. There are genetically at least two type of hydrothermal breccias have recognized in the research area, i.e. magmatic-hydrothermal breccia and phreatomagmatic breccia. Magmatic hydrothermal breccias are mostly occured in contact between hornblende microdiorite or quartz diorite and hornblende-pyroxene diorite, characterized by angular fragments/clasts supported or inﬁlled by silicas, carbonates and sulphides matrix derived from hydrothermal ﬂuids precipitation. Phreatomagmatic breccias are characterized by abundant of the juvenile clasts, indicated contact between hot magma with ﬂuid or water as well as many wall rock fragments such as altered diorites and volcaniclastic rock clasts set in clastical matrix. The juvenile clasts usually compossed by volcanic glasses and aphanitic rocks in rounded-irregular shape. Both veining and brecciation processes have an important role in gold and copper mineralisation of the Randu Kuning Porphyry Cu-Au and epithermal Au-base metals deposits, mostly related to the presence of quartz veins/veinlets containing signiﬁcant sulphides, i.e., quartz with thin centre line sulphides (Abtype) veins, pyrite±chalcopyrite (C type) veinlets, pyrite+quartz± chalcopyrire±carbonate (D type) veins of porphyry types as well as epithermal environment quarts+ sulphides+carbonate veins.

Keywords

Veins, Hydrothermal breccia, Porphyry, Epithermal

Full Text:

PDF

References

Baker, E.M., Kirwin, D.J., and Taylor, R.G. (1986) Hydrothermal Breccia Pipes, Contributions of the Economic Geology Research Unit, Geology Department James Cook University of North Queensland, 45p. Bemmellen, van, R.W. (1949) The Geology of Indonesia, and Adjacent Archipelagoes, Vol. IA, Gov. Print. Ofﬁce, Martinus Nijhoff, the Hague. Carlile, J.C. dan Mitchell, A.H.G. (1994) Magmatic Arcs and Associated Gold and Copper Mineralisation in Indonesia, Journal of Geochemical Exploration, Elsevier Science, Amsterdam, 50: 92-142. Corbett, G. (2008) Inﬂuence of Magmatic Arc Geothermal Systems on PorphyryEpithermal Au-Cu-Ag Exploration Models, Paper presented at the Terry Leach Symposium, Sydney, 17 October 2008. Australian Institute of Geoscientist Bulletin 48. Corbett, G. (2011) Comments on The Exploration Potential of The Wonogiri Porphyry Cu-Au Project, Central Java, Indonesia, Corbett Geological Services Pty. Ltd., Unpublished, 27p. Corbett, G. (2012) Further Comments on The Wonogiri Porphyry Cu-Au Project CentralJava, Indonesia, Corbett Geological Services Pty. Ltd., Unpublished, 37p. Creasey, S.C. (1966) Hydrothermal Alteration, op.cit. p. 51-74. Gustafson, L.B. dan Hunt, J.P. (1975) The Porphyry Copper Deposit at El Salvador, Chile, Economic Geology 70: 857–912. Hamilton,W.B. (1979) Tectonics of the Indonesian Region. Professional Paper 1078, U.S. Geolology Survey, Washington, DC., 345 p. Hartono, H.G. (2010) The Role of Paleovolcanism in The Tertiary Volcanic Rock Product Setting at Gajahmungkur Mt., Wonogiri, Central Java, Dissertation in UNPAD, Unpublished, 190p. Hedenquist, J.W., Arribas, A.J., and Reynolds, T.J. (1998) Evolution of Intrusion-Centered Hydrothermal System: Far SoutheastLepanto Porphyry and Epithermal Cu-Au deposits, Philipines, Economic Geology 93: 373–404. Imai, A., Shinomiya, J., Soe, M.T., Setijadji, L.D., Watanabe, K., and Warmada, IW. (2007) Porphyry-Type Mineralization at Selogiri Area, Wonogiri Regency, Central Java, Indonesia, Resources Geology 57: 230–240. Isnawan, D., Sukandarrumidi and Sudarno, I. (2002) Kontrol Struktur Geologi Terhadap Jebakan Tembaga Sebagai Arahan Eksploitasi di Daerah Ngerjo dan Sekitarnya Kecamatan Tirtomoyo, Kabupaten Wonogiri Propinsi Jawa Tengah, Gama Sains IV (2) Juli 2002, pp.149–157. Katili, J. A., 1989. Evolution of the Southeast Asian arc complex, Geology Indonesia. Jakarta, 12: 113–143. Kouzmanov, K., Moritz, R., von Quadt, A., Chiaradia, M., Peytcheva, I., Fontignie, D., Ramboz, C., and Bogdanov, K. (2009) Late Cretaceous Porphyry Cu and Epithermal CuAu Association in the Southern Panagyurishte District, Bulgaria: the Paired Vlaykov Vruh and Elshitsa Deposits, Mineralium Deposita 44: 611–646. Lawless, J.V. and White, P.J. (1990) Ore-Related Breccia: A Revised Genetic Classiﬁcation, with Particular Reference to Epithermal Deposits, 12th New Zealand Geothermal Workshop 1990. Maryono, A., Setijadji, L.D., Arif, J., Harrison, R., Soeriaatmadja, E. (2012) Gold, Silver and Copper Metallogeny of the Eastern Sunda Magmatic Arc Indonesia, Proceeding of Banda and Eastern Sunda Arcs 2012 MGEI Annual Convention, 26-27 November 2012, Malang, East Java, Indonesia, pp. 23–38. Muntean, J.L. and Einaudi, M.T. (2001) Porphyry-Epithermal Transition: Maricunga Belt, Northern Chile, Economic Geology 96: 743–772. Muthi, A., Basten, I.G., Suasta, I.G.M., and Litaay, N.E.W. (2012) Characteristic of Alteration and Mineralization at Randu KuningWonogiri Project, Proceeding of Banda and Eastern Sunda Arcs 2012 MGEI Annual Convention, 26-27 November 2012, Malang, East Java, Indonesia, pp. 117–132. Seedorff, E., Dilles, J.H., Proffett, Jr., J.M., Einaudi, M.T., Zurcher, L., Stavast, W..J.A, Jonhson, D.A., and Barton, M. (2005) Porphyry Deposit: Characteristics and Origin of Hypgene Features, Economic Geology 65: 251–298. Setijadji, L.D., Kajino, S., Imai, A., and Watanabe, K. (2006) Cenozoic Island Arc Magmatism in Java Island (Sunda Arc, Indonesia): Clues on Relationships between Geodynamics of Volcanic Centers and Ore Mineralization, Resources Geology 56: 267–292. Setijadji, L.D., and Maryono, A. (2012) Geology and Arc Magmatism of the Eastern Sunda Arc, Indonesia, Proceeding of Banda and Eastern Sunda Arcs 2012 MGEI Annual Convention, 26-27 November 2012, Malang, East Java, Indonesia, p.1–22. Sillitoe, R.H. (1985) Ore-Related Breccias in Volcanoplutonic Arcs, Economic Geology 80: 1467–1514. Sillitoe, R.H. (2010) Porphyry Copper System, Economic Geology 105: 3–41. Smyth, H.L., Hall, R. and Nichols, G. (2008) Cenozoic Volcanic Arc History of East Java Indonesia: The Stratigraphic Record of Eruption on An Active Continental Margin, The Geological Society of America Special Paper No. 436, p. 199–221. Suasta, I.G.M and Sinugroho, I.A. (2011) Occurrence of Zoned Epithermal to Porphyry Type Cu-Au Mineralization at Wonogiri, Central Java, Proceeding of The 36 th HAGI and 40 th IAGI Annual Convention. Suprapto (1998) Model Endapan Emas Epitermal Daerah Nglenggong, Kecamatan selogiri, Kabupaten Wonogiri, Jawa Tengah. Tesis Magister, Program Studi Rekayasa Pertambangan, Fakultas Pasca Sarjana, Institut Teknologi Bandung, 47 p. Surono, Toha, B., and Sudarno, I. (1992) Geological map of the Surakarta-Giritontro Quadrangles, Java, Geological Research and Development Centre, Bandung. Sutarto, Idrus, A., Putranto, S., Harijoko, A., Setijadji, L.D., Meyer, F.M., and Danny, R. (2013) Veining Paragenetic Sequence of The Randu Kuning Porphyry Cu-Au Deposit at Selogiri Area, Central Java. Extended Abstract: CD Proceeding of The 38 HAGI and 42 th nd IAGI Annual Convention and Exibition Medan, 28-31 October 2013. Sutarto, Idrus, A., Meyer, F.M., Harijoko, A., Setijadji, L.D., and Danny, R. (2013) The Dioritic Alteraation Model of The Randu Kuning Porphyry Cu-Au, Selogiri Area, Central Java. Proceedings International Conference on Georesources and Geological Engineering, December 11-12, 2013 Yogyakarta, ISBN 978-602-14066-5-6. p.122-132. Prihatmoko, S., Digdowirogo, S., and Kusumanto, D. (2002) Potensi Cebakan Mineral di Jawa Tengah dan Daerah Istimewa Yogyakarta. Prosiding Seminar Geologi Jawa Tengah dan Daerah Istimewa Yogyakarta, Ikatan Ahli Geologi Indonesia Pengda Yogyakarta, p. 87–108.

DOI: https://doi.org/10.22146/jag.26982