Sutarto, Sutarto and Idrus, Arifudin and Harijoko, Agung and Setijadji, Lucal and Meyer, Franz Michael and Putranto, Sapto and Danny, Rama (2015) HYDROTHERMAL BRECCIAS OF THE RANDU KUNING PORPHYRY Cu-Au AND EPITHERMAL Au DEPOSITS AT SELOGIRI AREA, CENTRAL JAVA INDONESIA. In: SEminar Nasional Kebumian ke8 UGM, 15-16 October 2015, UGM.
|
Text
2015_Sutarto, et al., Hydrothermal Breccias in Selogiri, Central Java.pdf Download (2MB) | Preview |
Abstract
south-east from Solo city or approximately 70 km east of Yogyakarta city. Many Tertiary hydrothermal altered dioritic rocks 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 produduced a very complex of quartz-sulphides veins and hydrothermal breccias crosscutting relationship. 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 hornblendepyroxene diorite, characterized by angular-subrounded of various altered diorites fragments/clasts supported or infilled by silicas, carbonates, magnetites and sulphides (chalcopyrites and pyrites) matrix derived from hydrothermal fluids precipitation. Whereas the phreatomagmatic breccias are characterized by abundant of the juvenil clasts, indicated contact between hot magma with fluid or water as well as many wall rock fragments such altered diorites, volcaniclastic, sedimentary and metamorphic rocks clasts set in sand-granule sized clastical matrix and lack of hydrothermal mineral as open space infilling. The juvenil clasts usually compossed by volcanic glasses and aphanitic rocks in rounded-irregular shape. Brecciation also 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. Mineralisation mostly were found as both of open space infilling and dessimetaned textures, particularly with quartz-sulphides veins overprinting.
| Item Type: | Conference or Workshop Item (Paper) |
|---|---|
| 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 07:34 |
| Last Modified: | 22 Jan 2019 07:34 |
| URI: | http://eprints.upnyk.ac.id/id/eprint/18094 |
Actions (login required)
 |
View Item |