"Daerah penelitian secara administratif berada di daerah Ganda-Ganda, Kecamatan
Petasia, Kabupaten Morowali Utara, Provinsi Sulawesi Tengah. Pelapukan batuan
ultramafik menghasilkan endapan laterit dengan karakteristik yang berbeda disetiap
daerah. Penelitian ini bertujuan untuk mengetahui karakteristik mineralogi dan geokimia
endapan nikel laterit dan batuan dasar, serta derajat laterisasi dan distribusinya pada
daerah penelitian. Data yang digunakan merupakan data lapangan dari 6 profil laterit
berupa 39 sampel batuan dan tanah, serta data assay dari analisis XRF (X-Ray
Fluorescence) dan XRD (X-Ray Diffraction). Profil laterit pada daerah penelitian terdiri
dari limonit dengan kadar Ni 0,2 – 0,47%, serta saprolit 0,23 – 0,89% (termasuk sampel
bedrock). Sampel bedrock yang merupakan bongkah batuan disekitar lapisan saprolit
secara mineralogi dianggap mewakili batuan dasar di bawah permukaan, memiliki kadar
Ni 0,56 – 0,89% dan diinterpretasikan merupakan rocky saprolite. Nikel pada limonit
secara dominan berasosiasi dengan mineral goetit dan gibsit, sementara pada saprolit
berasosiasi dengan mineral serpentin (lizardit dan antigorit), talk, olivin (forsterit dan
fayalit), dan piroksen (enstatit). Derajat laterisasi pada daerah penelitian menunjukkan
limonit mengalami moderate – strongly lateritized, saprolit kaolinitized – strongly
laterized dan Index of laterization (IOL) berkorelasi positif dengan hubungan korelasi
kuat terhadap Fe pada limonit, saprolit, dan bedrock, sementara berkorelasi negatif
terhadap Ni dengan hubungan lemah pada sampel bedrock.
The research area is administratively located in Ganda-Ganda, Petasia District,North Morowali Regency, Central Sulawesi Province. Weathering of ultramafic rocksproduces laterite deposits with different characteristics in each area. This study aims todetermine the mineralogical and geochemical characteristics of nickel laterite depositsand bedrock, as well as the degree of laterization and its distribution in the research area.The data used include field data from 6 laterite profiles consisting of 39 rock and soilsamples, as well as assay data from XRF (X-Ray Fluorescence) and XRD (X-RayDiffraction) analyses. The laterite profiles in the study area consist of limonite with Nicontent of 0.2 – 0.47%, and saprolite with Ni content of 0.23 – 0.89% (including bedrocksamples). The bedrock samples, which are rock fragments around the saprolite layer, aremineralogically considered to represent the bedrock beneath the surface, with Ni contentof 0.56 – 0.89% and are interpreted as rocky saprolite. Nickel in limonite is predominantlyassociated with the minerals goethite and gibbsite, while in saprolite it is associated withserpentine minerals (lizardite and antigorite), talc, olivine (forsterite and fayalite), andpyroxene (enstatite). The degree of laterization in the study area shows that limonite ismoderately to strongly lateritized, saprolite is kaolinitized to strongly laterized, and theIndex of Laterization (IOL) positively correlates with Fe in limonite, saprolite, andbedrock, while it negatively correlates with Ni with a weak correlation in bedrocksamples."
Depok: Fakultas Matematika Dan Ilmu Pengetahuan Alam Universitas Indonesia, 2024