Petrogenesis of Andesite in Bukitcula, Baleendah District, Southern Bandung, West Java

Nouval Muamar Asrial, Mega Fatimah Rosana, Kurnia Arfiansyah Fachrudin, Nazihah Nordin

Abstract


Administratively, Bukitcula Lava located in the area of Baleendah, Southern Bandung, West Java . Geographically located at Longitude 107o36'00" to 107o39'00" and Latitude 7o00'00" to 7o02'42". Baleendah Lava Complex consisted of steeply hill composed by andesite. Petrology, petrography and geochemical studies (XRF analysis) were used to understand the detail of rock characteristics. Petrological analysis studies shows mineral abundances of feldspar, amphiboles, pyroxenes and opaque mineral. Petrographical analysis show abundances of plagioclase, pyroxene, hornblende, and groundmass composed by plagioclase microlites, volcanic glass, and opaque mineral. Texture found in petrography analysis shows glomeroporphyritic, sieve, pyroxene penetration twin, zoning, and trachytic. Based on geochemical analysis, Bukitcula Lava composed by basaltic andesite and andesite according to TAS diagram. The magmatic series of rocks is Calc-Alkali and Tholeiitic series, with High-K and Medium-K (Calc-Alkaline Series) magma group. Magma interract with continental crust, with tectonical setting related on Island Arc Calc-Alkaline Basalt, and origin of magma ranged ranged from ± 139 km - ± 148 km in the Benioff zone. We conclude that the forming of Baleendah Lava Complex was influenced by fractional crystalization and slightly magma mixing.

References


Alzwar, M., H. Samodra, J. I. Tarigan. 1988. Pengantar Dasar Ilmu Gunungapi. Bandung : Penerbit Nova.

Cox, K.G. (1979): The Interpretation of Igneous Rocks. George Allen and Unwin, London.

Irvine, T. N. & W. R. A. Baragar 1971. A guide to the chemical classification of the common volcanic rocks. Can. J. Earth Sci. 8, 523-48.

Le Bass, M. J., R. W. Le Maitre, A. Streckeisen & B. Zanettin (1986). A chemical classification of volcanic rocks based on the total alkali-silica diagram. J. Petrology 27

Mullen, E. D. 1983. MnO/TiO2/P2O5: a minor element discriminant for basaltic rocks of oceanic environments and its implications for petrogenesis. Earth Planet. Sci. Lett. 62, 53-62.

Pearce, T. H., Gorman, B. E. & Birkett, T. C. 1977. The Relationship Between Major Element Geochemistry and Tectonic Environment of Basic and Intermediate Volcanic Rocks. Earth and Planetary Science Letters 36, 121–132.

Peccerillo, A. & Taylor, S. R. 1976. Geochemistry of Eocene Calc- Alkaline Volcanic Rocks From the Kastamonu Area, Northern Turkey. Contributions to Mineralogy and Petrology 58, 63–81.

Whitford. 1979. Classification of Igneous Rock by Silica. Dalam Rollinson, H. R. 1993. Using Geochemical Data. John Willey & Sons Inc : New York

Wilson, M. 1989. Igneous Petrogenesis Global Tectonic Approaach, Dordrecht: Springe




DOI: https://doi.org/10.24198/gsag.v3i3.23851

Refbacks

  • There are currently no refbacks.


toto slot