PEMBENTUKAN PRISMA AKRESI DI TELUK CILETUH KAITANNYA DENGAN SESAR CIMANDIRI, JAWA BARAT

Lili Sarmili, Deny Setiady

Abstract


Kumpulan sesar naik yang ditafsirkan dari penampang seismic refleksi di teluk Ciletuh mengindikasikan adanya prisma akresi di daerah penelitian. Prisma akresi di daerah penelitian terletak di perairan teluk Ciletuh yang ditandai olef kumpulan sesar naik akibat adanya zona tumbukan antara kerak benua dan kerak samudera. Kerak samudera yang terangkat dan tersingkap di daratan teluk Ciletuh berupa batuan basalt (lava bantal), batuan ultra basa dan batuan bancuh. Prima akresi ini diduga berumur lebih tua dari prisma akresi yang masih terjadi saat ini, diperkirakan umurnya Tersier. Posisi prisma akresi di daerah penelitian ini berada di utara zona subduksi yang masih aktif di selatan di pulau Jawa. Beberapa struktur sesar naik juga terdapat di utara teluk Pelabuhan Ratu. Kumpulan sesar naik di sekitar teluk Pelabuhan Ratu dapat dianggap sebagai prisma akresi tua, dan mempunyai kaitan dengan kumpulan sesar naik di teluk Ciletuh. Posisi sesar-sesar naik yang terpisah antara sesar naik di lokasi teluk Pelabuhan Ratu dan di teluk Ciletuh diperkirakan terpisah oleh suatu sesar. Sesar yang memisahkan kedua kumpulan sesar naik ini diduga adalah sesar Cimandiri dengan jenis sesar mendatar menganan

Kata kunci prisma akresi, teluk Ciletuh, batuan ultra basa, sesar sisnistral Cimandiri.


A series of thrust faults which is interpreted from seismic reflection profile at Ciletuh bay indicate the occurrence of accretionary prism in the study area. The accretionary Prism in the study area indicated by series of thrust faults as a product of the collision zone between continental crust and oceanic crust. Uplifted oceanic crust was exposed on Ciletuh mainland such as basaltic rocks, pillow lavas, ultra basic rocks and melange. The accretionary prism is thought to be older than the accretionary prism that is still occurs on south Java island, and it was estimated Tertiary in age. The position of accretionary prisms in this study area is in the northern active subduction zone in the south of Java island. Some thrust faults are also found in the northern of Pelabuhan Ratu Gulf. A series of these faults can be regarded as an old accretionary prism, and have a relationship with a series of thrust fault at Ciletuh bay. The position of these thrust faults separate between the thrust of Pelabuhan Ratu bay and the thrust of Ciletuh bay and estimated have been disturbed by a fault. Fault which separates these two sets thrust fault is interpreted due to Cimandiri dextral fault.

Keywords: the accretionary prism, Ciletuh bay, ultra basic rocks, Cimandiri sinistral fault.


Keywords


prisma akresi;teluk Ciletuh;batuan ultra basa;sesar sisnistral Cimandiri

References


Asikin, S., 1974, Evolusi Geologi Jawa Tengah dan sekitarnya Ditinjau dari Segi Teori Tektonik Dunia yang Baru, Disertasi Doktor, Departemen Teknik Geologi ITB, Tidak Dipublikasikan.

Bemmelen, R.W., van, 1949. The Geology of Indonesia. Government Printing Of?ce, Nijhoff, The Hague.

Clements, B., Hall, R. Smyth, H.R., and Cottam, M.A. 2009. Thrusting of a volcanic arc: a new structural model for Java, Petroleum Geoscience, Vol. 15, 2009, pp. 159-174

Darman, Herman dan F. Hasan Sidi, M.Sc. 2000.An Outline of The Geology of Indonesia. Ikatan Ahli Geologi Indonesia, Jakarta.

Davis, George H. 1996. Structural Geology of Rocks and Region, John Wiley and Sons, Inc, New York.

Hall, R., Blundell. 1996. Tectonic Evolutions of Southeast Asia. Geological Society Special Publication No. 106. London

Hamilton. W. 1979. Tectonics of Indonesian Region. U.S. Geological Survey Profesional Paper.

Hutchison, 1973. Tectonic evolution of Sundaland, a Phanerozoic synthesis: Bulletin of the Geological Society of Malaysia, v. 6, p. 61-86

Karig, D.E., dan Sharman G.F., 1975, Subduction and accreation in trenches, Geol. Soc. Amer. Bull., v. 86, hal 377-389.

Katili, J.A. 1980. Geotectonics of Indonesia : A Modern View. Jurusan Geologi, Institut Tekonologi Bandung.

Katili, J.A. 1989. Evolution of The Southeast Asian Arc Complex. Majalah ikatan Ahli Geologi Indonesia, Vol.12, No.1, July.

Martodjojo. 1984. Evolusi Cekungan Bogor. Jawa Barat. Ph.D Thesis ITB.

Martodjojo, S., Suparka S., Hadiwisastra, S., 1978, Status Formasi Ciletuh Dalam Evolusi Jawa Barat . Geologi Indonesia Vol 5.

Parkinson, C.D. Miyazaki, K. Wakita, K. Barber, A.J. & Carswell, D.A. 1998. An overview and tectonic synthesis of the pre-Tertiary very-high-pressure metamorphic and associated rocks of Java, Sulawesi and Kalimantan, Indonesia. Island Arc, 7, 184-200.

Rosana, M. F., Syafri, I.,Mardiana, U., Sulaksana, N., 2006: Petrology of Pre-Tertiary Mélange Complex of Gunung Badak, Sukabumi, West Java. Proceeding Persidangan Bersama Geosains ITB-UKM" Geosains dalam Pembangunan Ekonomi & Kesejahteraan Serantau, 19~20 December 2006, Langkawi-Malaysia

Sartono, S., dan Murwanto, H., 1987, Olitostrom sebagai batuan dasar di Jawa, proseding PIT XVI IAGI, 19 hal.

Satyana, A.H., 2005. Oligo-Miocene Carbonates of Java, Indonesia: Tectonic-Volcanic Setting and Petroleum Implications, Proc. Indonesian Petroleum Association, IPA05-G-031

Satyana, A.H. 2007. Central Java, Indonesia - a "terra incognita" in petroleum exploration. New considerations on the tectonic evolution and petroleum implications. In: Indonesian Petroleum Association, Proceedings 31st Annual Convention, 105-129.

Schiller, D.M. Garrard, R.A. & Prasetyo, L. 1991. Eocene submarine fan sedimentation in southwest Java. In: Indonesian Petroleum Association, Proceedings 20th Annual Convention, 125-182.

Sukamto, R. 1975. Peta Geologi Lembar Jampang dan Balekambang, Pusat Penelitian dan Pengembangan Geologi. Bandung.Suhaeli, E.T. 1977. The status of the melange complex in Ciletuh area, Southwest Java : Proceeding Indonesia Petroleum Assoc., 6th annual conv., hal 241-253.

Susilohadi., Christoph Gaedicke, and Axel Erhardt. 2005. Neogene Structures and Sedimentation History anlong The Sunda Forearc Basin off Southwest Sumatera and Southwest Java.International Journal of Marine Geology.

Thayyib S. Endang, Said S.E., Siswoyo, Prijomarsono S., 1977: The status of the Melange Complex in Ciletuh area, South - West Java. Proceedings IPA ke 6, Jakarta.




DOI: http://dx.doi.org/10.32693/jgk.13.3.2015.272