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Journal : Jurnal Geologi dan Sumberdaya Mineral (Journal of Geology and Mineral Resources)

Karakteristik Geokimia Basalt Busur Gunungapi Tholeitik Formasi Manamas di Sungai Metan, Baun, Timor Angga Jati Widiatama; Lauti Dwita Santy; Joko Wahyudiono; Sari Widyastuti; Lia Fitria Rahmatillah
Jurnal Geologi dan Sumberdaya Mineral Vol. 21 No. 3 (2020): Jurnal Geologi dan Sumberdaya Mineral
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33332/jgsm.geologi.v21i3.449

Abstract

Lava basalt berstruktur bantal tersingkap di Sungai Metan, Baun, Timor, yang termasuk dalam anggota batuan gunung api Formasi Manamas. Penelitian geokimia batuan dilakukan menggunakan metode analisis XRF dan ICP-MS menunjukkan basalt memiliki karakteristik basalt subalkalin, bersifat tholeitik yang terbentuk pada busur gunungapi tholeitik akibat penunjaman Lempeng Samudera Hindia di bawah Busur Banda yang berumur Miosen-Pliosen. Basalt subalkali di Sungai Metan menunjukkan pengayaan unsur logam dan unsur large ion lithophile (LILE) yang dipengaruhi fluida, ditunjukkan oleh adanya hubungan positif antar unsur logam jejak mudah bergerak. Pengayaan yang dipengaruhi oleh fluida ditafsirkan sebagai produk akibat meleburnya lempeng samudera yang menunjam di bawah busur gunung api.Katakunci: Basalt, busur tholeitik, Sungai Metan, Formasi Manamas, Timor.
Provenance and Paleoclimate Analysis of Sandstone from Meluhu Formation in Kendari, Southeast Sulawesi. Muhammad Firdaus; Dwi Novitasari; Angga Jati Widiatama; Achmad Fachruddin; Lauti Dwita Santy
Jurnal Geologi dan Sumberdaya Mineral Vol. 24 No. 2 (2023): JURNAL GEOLOGI DAN SUMBERDAYA MINERAL
Publisher : Pusat Survei Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33332/jgsm.geologi.v24i2.776

Abstract

The Meluhu Formation consists of quartz sandstone, red shale, siltstone, and mudstone at the bottom part, and alternating black shale, sandstone, and thin limestone in the upper part. Petrographic components composition can reveal the litho-tectonic setting of a region. The composition of sandstone can be done by determining and counting the proportion of a quartz minerals, feldspar, and rock fragment from thin sections using petrographic analysis. This result can guide to depositional setting and paleoclimates of a region. The Provenance and paleoclimates studies of Meluhu Sandstone are still relatively new. The purpose of this study was to find out the provenance and paleoclimate of sandstone of Meluhu Formation which is exposed in 14 sites along Kendari and adjacent area. The method used to make petrographic observations followed by data processing using the point counting method. The sandstone in this study area was classified into sublitharenite, lithic arenite, arkose, subarkose, and greywacke. The origin of rock was interpreted as located in the recycled orogenic province, interior craton, and undissected arc. The paleoclimate that occurred in the formation of these siliciclastic rocks was arid to humid. Keywords: Meluhu Formation, provenance, paleoclimate, sandstone.