Electronic Theses and Dissertation

Daerah IUP PT ANTAM Tbk. Blok X, Kabupaten Sanggau, Provinsi Kalimantan Barat merupakan salah satu wilayah yang memiliki potensi endapan bauksit laterit yang terbentuk akibat proses pelapukan intensif batuan kaya alumina. Karakteristik dan kualitas bauksit laterit dipengaruhi oleh berbagai faktor, di antaranya batuan induk dan morfologi. Penelitian ini bertujuan untuk mengidentifikasi karakteristik dan kualitas zona bauksit laterit serta menganalisis pengaruh batuan induk dan morfologi terhadap pembentukannya. Metode yang digunakan meliputi pemetaan geologi dan geomorfologi skala 1:25.000, analisis petrografi, pengamatan sumur uji, analisis ketebalan profil laterit, serta analisis geokimia menggunakan metode X-Ray Fluorescence (XRF). Hasil penelitian menunjukkan bahwa daerah penelitian tersusun atas Satuan Endapan Aluvial (Qal), Satuan Granodiorit (Kgd), dan Satuan Diorit Kuarsa (Kdq), serta empat satuan geomorfologi yaitu Struktural (S3), Denudasional (D2), dan Fluvial (F1 dan F3). Bauksit laterit pada granodiorit memiliki ukuran konkresi 6–11 cm dengan kandungan kuarsa 15–30% dan hematit 3–7%, sedangkan pada diorit kuarsa memiliki ukuran konkresi 4–11 cm dengan kandungan kuarsa 5–12% dan hematit 7–15%. Ketebalan rata-rata lapisan bauksit pada granodiorit sebesar 1,93 m dan pada diorit kuarsa sebesar 1,68 m. Hasil analisis geokimia menunjukkan bahwa bauksit pada granodiorit memiliki rata-rata kandungan Al₂O₃ sebesar 44,56 wt.% termasuk kedalam kategori kadar tinggi, SiO₂ sebesar 24,48 wt.%, dan Fe₂O₃ sebesar 6,99 wt.%, sedangkan bauksit pada diorit kuarsa memiliki rata-rata kandungan Al₂O₃ sebesar 49,97 wt.% termasuk kedalam kategori kadar sedang-tinggi, SiO₂ sebesar 11,61 wt.%, dan Fe₂O₃ sebesar 8,67 wt.%. Hasil penelitian menunjukkan bahwa batuan induk dan morfologi berpengaruh terhadap karakteristik dan kualitas zona bauksit laterit, dimana bauksit dengan kualitas terbaik berkembang pada batuan induk diorit kuarsa yang berada pada morfologi miring dengan tingkat laterisasi kuat dan kandungan alumina yang lebih tinggi dibandingkan granodiorit.

The PT ANTAM Tbk. Mining Business Permit Area (IUP), Block X, Sanggau Regency, West Kalimantan Province, is one of the regions with significant lateritic bauxite potential formed through intensive weathering of alumina-rich rocks. The characteristics and quality of lateritic bauxite are influenced by several factors, including parent rock lithology and morphology. This study aims to identify the characteristics and quality of the lateritic bauxite zone and to analyze the influence of parent rock and morphology on its formation. The research methods employed include geological and geomorphological mapping at a scale of 1:25,000, petrographic analysis, test pit observations, lateritic profile thickness analysis, and geochemical analysis using the X-Ray Fluorescence (XRF) method. The study area consists of the Alluvial Unit (Qal), Granodiorite Unit (Kgd), and Quartz Diorite Unit (Kdq), as well as four geomorphological units, namely Structural (S3), Denudational (D2), and Fluvial (F1 and F3) units. Lateritic bauxite developed over granodiorite exhibits concretion sizes ranging from 6–11 cm, with quartz contents of 15–30% and hematite contents of 3–7%, whereas lateritic bauxite developed over quartz diorite exhibits concretion sizes ranging from 4–11 cm, with quartz contents of 5–12% and hematite contents of 7–15%. The average thickness of the bauxite layer is 1.93 m over granodiorite and 1.68 m over quartz diorite. Geochemical analysis indicates that bauxite developed over granodiorite contains an average Al₂O₃ content of 44.56 wt.% and is classified as high-grade bauxite, with SiO₂ and Fe₂O₃ contents averaging 24.48 wt.% and 6.99 wt.%, respectively. In contrast, bauxite developed over quartz diorite contains an average Al₂O₃ content of 49.97 wt.% and is classified as moderate- to high-grade bauxite, with average SiO₂ and Fe₂O₃ contents of 11.61 wt.% and 8.67 wt.%, respectively. The results indicate that parent rock and morphology significantly influence the characteristics and quality of the lateritic bauxite zone, with the highest-quality bauxite occurring over quartz diorite in gently sloping terrain, characterized by a strong degree of laterization and higher alumina content compared to that developed over granodiorite.