Petrology and Geochemistry of Granitic Rocks in South Sulawesi, Indonesia: Implication for Origin of Magma and Geodynamic Setting

Petrology and geochemical characteristics of granitic rocks from South Sulawesi, especially from Polewaliand Masamba area are presented in order to elucidate their origin of magma and geodynamic setting. The granitic rocks in these areas are dominated by granodiorite and granite in composition. Quartz, K-feldspar and plagioclase occur as major phases with hornblende and biotite as major ferromagnesian minerals. All of the samples were plotted in calc-alkaline field, show metaluminous affinity and typical of I-type granitic rock. Harker diagram indicates that granitic rocks experienced fractional crystallization during magmatic evolution. Both groups displayed an extreme enrichment of LILE, LREE and a slight negative Eu anomaly which resemble upper continental crust affinity. They were produced from partial melting of upper continental crust and have close relationship of sources composition within a suite. The geochemical characteristics explained the arc related subduction environment which later give an evidence of continent-continent collision between Australia-derived microcontinent and Sundalandto form continental arc environment.

Authors:

• Adi Maulana
• Koichiro Watanabe
• Akira Imai
• Kotaro Yonezu

Keywords:

• Geochemistry
• Granitic Rock
• Petrology
• Sulawesi

References:

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