The characterised of Serpentinized Ultramafic Rocks from South Sulawesi, Indonesia
| Main Authors: | Maulana, Adi, Ellis, David, Christy, Andrew, Imai, Akira, Watanabe, Koichiro |
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| Format: | Article |
| Bahasa: | eng |
| Terbitan: |
International Symposium on Earth Science and Technology
, 2012
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| Subjects: | |
| Online Access: |
http://repository.unhas.ac.id/handle/123456789/1511 |
Daftar Isi:
- This paper report for the first time petrology and geochemistry of highly serpentinzed ultramafic rocks from South Sulawesi, Indonesia. Their petrogenesis and their geodynamic significance were also discussed
- Highly serpentinised ultramafic rocks occur in two separated basement complexes in the South Sulawesi, Bantimala and Barru blocks. The characteristics of the ultramafic are assessed using petrology and geochemistry data. The Bantimala ultramafic rocks consists mainly of serpentinised peridotite (harzburgite and dunite) and cumulates clinopyroxenite with locally podiform chromitite found enclosed in the peridotite bodies. They have been metamorphosed into greenschist facies. In contrast, the Barru ultramafic rocks are composed of strongly serpentinised and metamorphosed lherzolite and harzburgite peridotite and podiform chromitite. They suffered from amphibolite facies metamorphism overprint and later intruded by huge body of volcanic rocks. The absent of garnet indicates that the ultramafic rocks in both blocks were not experienced high-pressure condition. Geochemical classification suggests that all the Bantimala and Barru ultramafics are different from each other. Based on trace element analysis including Nb and Ta anomalies as well as the Cr-spinel compositions suggests that the Barru lherzolite has had some melt extracted and is derived from suprasubduction zone (SSZ) environment, while the Bantimala dunite, harzburgite and clinopyroxenite are cumulates origin. Moreover, the Cr-spinel composition from the podiform chromitite in both blocks showed a very different characteristics, suggesting the different sources.