PRIBADI, BIMA SUSANTIKA PERKASA (2015) STUDI GEOLOGI, ALTERASI, DAN MINERALISASI DAERAH “X”, KECAMATAN SEBUKU, KABUPATEN NUNUKAN, PROVINSI KALIMANTAN UTARA. Other thesis, UPN "Veteran" Yogyakarta.
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Abstract
Lokasi penelitian secara administratif terletak di daerah konsesi
pertambangan PT. Sago Prima Pratama yaitu di Kecamatan Sebuku, Kabupaten
Nunukan, Provinsi Kalimantan Utara. Secara geografis daerah penelitian berada
pada 524650 mE - 528650 mE dan 431450 mN - 433450 mN (UTM zona 50N)
dengan luas area 4140m2.
Pola pengaliran yang berkembang adalah tipe radial yang dikontrol oleh
litologi dan morfologi. Bentuk lembah V menandakan stadia muda. Geomorfologi
daerah penelitian dibagi menjadi 7 satuan bentuklahan yaitu Bukit Intrusi (V1),
Rawa (F1), Pit (H1), Jalan Hauling (H2), Borrow Pit (H3), Stockpile (H4), dan
Waste Dump (H5).
Susunan stratigrafi daerah penelitian dari tua ke muda adalah Satuan
Intrusi Andesit (Plistosen Awal), Satuan Breksi Diatrem (Plistosen Awal -
Tengah), Satuan Breksi Hidrotermal (Plistosen Tengah - Akhir), dan Endapan
Aluvial (Holosen – Resen).
Struktur geologi menjadi faktor penting pengontrol mineralisasi di daerah
penelitian. Struktur geologi yang berkembang berupa sesar mendatar kiri, sesar
mendatar kanan, kekar gerus dan kekar tarik dengan arah umum NW – SE dan
arah NE – SW.
Himpunan mineral yang dijumpai di lapangan, dapat dibagi menjadi empat
zonasi alterasi yaitu Zona Alterasi Silica (kuarsa, tridimit, dan kristobalit), Zona
Alterasi Alunite-Kaolin (halloisit, alunit, kaolinit, pirofilit, kuarsa, paragonit,
dickit, dan diaspor), Zona Alterasi Kaolin (kaolinit, smektit, illit, halloisit, klorit,
monmorillonit, dan dickit), dan Zona Alterasi Chlorite (klorit).
Proses mineralisasi di daerah penelitian terdiri dari dua tahap hidrotermal
yaitu tahap Volatile-rich Event (fase awal yang ditandai dengan mulai
terbentuknya alterasi), kemudian tahap Liquid-rich Event (pelindian wall rock,
pembentukan breksi hidrotermal, dan deposisi mineral bijih). Mineralisasi Au
berkembang pada wall rock bertekstur vuggy dan breksi hidrotermal dengan
fasies dari dari dalam ke luar: rotational, mosaic, dan crackle.
Tipe endapan mineral pada daerah penelitian termasuk dalam tipe endapan
sulfidasi tinggi kontrol struktur.
Kata kunci : Geologi, Alterasi, Mineralisasi, Breksi Hidrotermal, Sulfidasi Tinggi
The research area is administratively located in the area of the mining concession of PT. Sago Prima Pratama, District Sebuku, Nunukan, Northern Kalimantan Province. Geographically the research area is at 524650 mE - 528650 mE and 431450 mN - 433450 mN (UTM zone 50S) with wide area 4140m2.
Drainage patterns that develop are the radial type controlled by lithology and morphology. The valley forms V indicates the mature stadia. Geomorphology of the area is divided into 7 units landforms namely Intrusion Hill (V1), Swamp (F1), Pit (H1), Hauling Track (H2), Borrow Pit (H3), Stockpile (H4), and Waste Dump (H5).
Stratigraphic arrangement from old to young is Andesite Intrusion Unit (Early Pleistocene), Diatreme Breccias (Early – Middle Pleistocene), Hydrothermal Breccias (Middle - Late Pleistocene), and the alluvial deposit (Holocene -Recent).
The geological structure is an important factor controlling the mineralization in the research area. Geological structures that develop are left slip fault, rigt slip fault, shear joint, and tension fracture with the general direction of the NW-SE and NE-SW.
The assemblages of minerals found in the field, can be divided into four alteration zones namely silica alteration zone (quartz, tridymite, and crystobalite), Alunite-Kaolin alteration zone (halloysite, alunite, kaolinite, pyrophyillite, quartz, paragonite, and diaspore), Kaolin alteration zones (kaolinite, smectite, illite, halloysite, chlorite, montmorillonite, and dickite), and Chlorite alteration zone.
The process of mineralization in the research area sequence consist of two phases, namely Volatile-rich Event (initial phase is characterized by the presence of hydrothermal alteration), and Liquid-rich Event (wall rock leaching, hydrothermal breccias forming, and metal deposition). Au mineralization is develop in the vuggy texture of wall rock and hydrothermal breccias with facies from inner to outer is rotational, mosaic, and crackle.
The deposit type in the research location included the high sulfidation structural controlled.
Keywords: Geology, Alteration, Mineralization, Hydrothermal Breccias, High Sulfidation
| Item Type: | Thesis (Other) |
|---|---|
| Subjek: | Q Science > QE Geology |
| Divisions: | x. Faculty of Engineering, Science and Mathematics > School of Engineering Sciences |
| Depositing User: | Eko Suprapti |
| Date Deposited: | 26 May 2016 06:39 |
| Last Modified: | 26 May 2016 06:39 |
| URI: | http://eprints.upnyk.ac.id/id/eprint/2574 |
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