Identifikasi Pola Struktur Geologi Sebagai Pengontrol Sebaran Mineral Radioaktif Berdasarkan Kelurusan Pada Citra Landsat-8 di Mamuju, Sulawesi Barat

Frederikus Dian Indrastomo, I Gde Sukadana, Suharji Suharji

DOI: http://dx.doi.org/10.17146/eksplorium.2017.38.2.3874

Sari


Abstrak

Daerah Mamuju dan sekitarnya tersusun atas batuan gunung api dengan komposisi mineral mengandung unsur radioaktif seperti uranium (U) dan thorium (Th). Konsentrasi unsur radioaktif di daerah ini mencapai 1.529 ppm eU dan 817 ppm eTh. Mineral-mineral radioaktif yang teridentifikasi terdiri dari thorianite, davidite, gummite, dan autunite. Aktivitas tektonika kemunculan gunung api menyebabkan terbentuknya struktur-struktur geologi yang mengontrol pembentukan kompleks gunung api dan mineralisasi U-Th di daerah tersebut. Identifikasi struktur geologi regional dan rinci di lapangan sangat sulit dilakukan karena vegetasi yang lebat dan tingkat pelapukan yang tinggi. Kelurusan hasil interpretasi dari citra Landsat-8 merupakan manifestasi keberadaan struktur geologi yang mengontrol keberadaan U dan Th. Analisis kelurusan punggung bukit menggunakan formula Sastratenaya digunakan untuk mengetahui umur dan kronologi kelurusan yang terbentuk. Pengukuran laju dosis di daerah penelitian menunjukkan kecenderungan arah sebaran anomali radioaktivitas berarah tenggara–baratlaut. Hasil analisis menggunakan formula Sastratenaya menunjukkan bahwa struktur yang terbentuk adalah struktur berumur relatif tua dan memiliki arah dominan tenggara–baratlaut (N 140–150o E). Berdasarkan interpretasi kelurusan, arah dominan memiliki kemiripan dengan arah sebaran gunung api dan sebaran radioaktivitas. Struktur yang mengontrol pembentukan gunung api dan terkait dengan mineralisasi U dan Th secara umum merupakan struktur berarah tenggara–baratlaut dan terbentuk bersamaan dengan proses mineralisasi U dan Th.

 

Abstract

Mamuju area and its surrounding are composed of volcanic rock containing uranium (U) and thorium (Th) elements. Radioelements concentrations in the area reach 1,529 ppm eU and 817 ppm eTh. Radioactive minerals identified in the area are thorianite, davidite, gummite, and autunite. The geological structures were formed by tectonic activities which controlled the creation of volcanic complex and U-Th mineralization in the complex. Identification of geological structure in the field is very difficult due to densely vegetation and higly degree of weathering. The interpreted lineaments from Landsat-8 imagery are the manifestation of geological structures which have controlled the existence of U and Th. Lineaments analysis using Sastratenaya formula is used to obtain the relative age and chronologies of the lineaments. Dose rate measurements in the area show the trend of radioactivitiy anomalies are trending northwest–southeast. The Sastratenaya formula results the formed structures are relatively older and dominantly directing northwest–southeast (N 140o–150o E). Based on the linement interpretation, the dominant direction has similliarity with volcanic and radioactivity distribution. Structures which controlling the volcanic formation and related to U and Th mineralization generally are the northwest–southeast trending structures, which were created along with U and Th mineralization.


Kata Kunci


uranium; thorium; struktur geologi; kelurusan; formula Sastratenaya; landsat-8

Teks Lengkap:

PDF

Referensi


[1] D. Iskandar, Syarbaini, and Kusdiana, “Map of Environmental Gamma Dose Rate of Indonesia.” National Nuclear Energy Agency,” 2014.

[2] H. Syaeful, I. G. Sukadana, and A. Sumaryanto, “Radiometric Mapping for Naturally Occurring Radioactive Materials (NORM) Assessment in Mamuju, West Sulawesi,” Atom Indones., vol. 40, no. 1, p. 35, May 2014.

[3] F. Bea, “Uranium,” in Encyclopedia of Geochemistry, C. . Marshall and R. W. Fairbridge, Eds. Kluwer Academic Publishers, London, 1999, p. 712.

[4] S. Krishnaswami, “Thorium,” in Encyclopedia of Geochemistry, C. . Marshall and R. W. Fairbridge, Eds. Kluwer Academic Publishers, London, 1999, p. 712.

[5] N. Ratman and S. Atmawainata, “Peta Geologi Lembar Mamuju, Sulawesi,” Bandung, 1993.

[6] F. D. Indrastomo, I. G. Sukadana, A. Saepuloh, A. H. Harsolumakso, and D. Kamajati, “Interpretasi Volkanostratigrafi Daerah Mamuju Berdasarkan Analisis Citra Landsat-8,” Eksplorium, vol. 36, no. 2, pp. 71–88, 2015.

[7] I. G. Sukadana, A. Harijoko, and L. D. Setijadji, “Tataan Tektonika Batuan Gunungapi di Komplek Adang, Kabupaten Mamuju, Provinsi Sulawesi Barat,” Eksplorium, vol. 36, no. 1, pp. 31–44, 2015.

[8] I. G. Sukadana, H. Syaeful, F. D. Indrastomo, K. S. Widana, and E. Rakhma, “Identification of Mineralization Type and Specific Radioactive Minerals in Mamuju, West Sulawesi,” J. East China Univ. Technol., vol. 39, pp. 39–48, 2016.

[9] W. S. Ibrahim, K. Watanabe, and K. Yonezu, “Structural and litho-tectonic controls on Neoproterozoic base metal sulfide and gold mineralization in North Hamisana shear zone, South Eastern Desert, Egypt: The integrated field, structural, Landsat 7 ETM+ and ASTER data approach,” Ore Geol. Rev., vol. 79, pp. 62–77, 2016.

[10] S. A. Meshkani, B. Mehrabi, A. Yaghubpur, and M. Sadeghi, “Recognition of the regional lineaments of Iran: Using geospatial data and their implications for exploration of metallic ore deposits,” Ore Geol. Rev., vol. 55, no. C, pp. 48–63, 2013.

[11] U.S. Geological Survey (USGS), “Landsat — A Global Land-Imaging Mission,” U.S. Geol. Surv. Fact Sheet 2012-3072, no. May, p. 4, 2012.

[12] A. S. Sastratenaya, “Deformation et Mobilite Megaprisme Tectonique De Pinoh-Sayan, Kalimantan, Indonesie,” These Docteur, L’Universite Louis Pasteur De Strassbourg, France, 1991.

[13] S. O. Hermi, R. Fadlalla, A. Elsheikh, M. Aziz, and S. Bouaziz, “Structural Interpretation of Lineaments Uses Satellite Images Processing : A Case Study in North-Eastern Tunisia,” pp. 440–455, 2017.

[14] Yuliastuti, H. Susiati, Y. Daud, and A. S. Sastratenaya, “Identifikasi Sistem Kelurusan Di Tapak Banten Menggunakan Data Citra Satelit SPOT-5,” JPEN, vol. 15, no. 1, pp. 9–16, 2013.

[15] International Atomic Energy Agency (IAEA), Guidelines for radioelement mapping using gamma ray spectrometry data. 2003.

[16] B. Brahmantyo and Bandono, “Klasifikasi Bentuk Muka Bumi (Landform) untuk Pemetaan Geomorfologi pada Skala 1:25.000 dan Aplikasinya untuk Penataan Ruang,” J. Geoaplika, vol. 1, no. 2, pp. 71–78, 2006.


Refbacks

  • Saat ini tidak ada refbacks.




EKSPLORIUM terindeks pada:

Google Scholar Logo SINTA Logo Logo IPI


Hak Cipta EKSPLORIUM, Buletin Pusat Pengembangan Bahan Galian Nuklir (e-ISSN 2503-426x p-ISSN 0854-1418)

Jl. Lebak Bulus Raya No. 9, Ps. Jumat, Jakarta 12440, Indonesia, Telp (021) 7691775, 7695394, 75912956 Fax (021)7691977.