REKAM SEDIMEN INTI UNTUK MEMPERKIRAKAN PERUBAHAN LINGKUNGAN DI PERAIRAN LERENG KANGEAN - Yani Permanawati; Tri Prartono; Agus Saleh Atmadipoera; Rina Zuraida; Yuanpin Chang (Pusat Penelitian dan Pengembangan Geologi Kelautan, 2016)
Sedimen inti dianalisis secara vertikal untuk memprediksi perubahan lingkungan saat sedimen terendapkan. Perairan segitiga Laut Jawa-Selat Makassar-Laut Flores (JMF) dilalui jalur arus lintas Indonesia/ARLINDO. Distribusi aliran ARLINDO yang masuk ke Selat Makassar terbagi dua arah aliran karena adanya Ambang Dewakang. Satu mengalir ke arah Tenggara melalui Laut Flores, sementara itu aliran lainnya bergerak ke arah Baratdaya menuju Selat Lombok melalui Laut Jawa. Penelitian ini menganalisis sedimen inti dari perairan Laut Jawa yang diwakili oleh Lereng Kangean. Metode penelitian menggunakan metode non-destructive yaitu pengamatan megaskopis dan pemindaian, dan metode destructive yaitu pencuplikan sistematis menggunakan 2 cm setiap interval 4 cm. Hasil cluster menunjukkan proses pengendapan tampak relatif seragam (88-0 cm) dari analisis sembilan variabel, antara lain: ukuran butir (mean) antara lempungâ€“pasir sangat halus, kecerahan sedimen (L*) sekitar 40,14-44,17, kerentanan magnet (Magnetik Susceptibility/MS) sekitar 13,60-116,70, karbonat biogenik (BC) dari pengamatan mikroskopis sekitar 3-10%, karbonat sekitar 17,36-50,17%, Total Organic Carbon (TOC) sekitar 0,76-2,01%, C/N sekitar 9,11-13,57, ln K/Ti sekitar 0,58-1,09, dan ln Mn/Cl sekitar -4,97- -4,24. Interpretasi karakter sedimen dari hasil deskriptif Principal Component Analysis/PCA menunjukkan penciri utama/F1 sebesar 28,10% dicirikan oleh pengaruh kuat dari variabel MS, ln K/Ti, dan ln Mn/Cl, menggambarkan karakter sedimen dengan pengaruh yang kuat dari daratan. Kata kunci: analisis vertikal, perubahan lingkungan, arus lintas Indonesia, karakter sedimen, penciri utamaA core sediment was vertically analyzed to predict environmental changes of the sediments deposition. Triangle waters of Java Sea-Makassar Strait-Flores Sea (JMF) are traversed by the Indonesian Throughflow or ARLINDO. Distribution of ARLINDO splited by morphological condition of the Dewakang Sill : Southeast ward of the Flores Sea and Southwest ward of the Lombok Strait through the Java Sea. The purpose of this study is to elaborate characteristics of the Kangean Slope’s core sediment corresponding to the Java Sea. The research method using non-destructive such as megaskopis and scanning method, and destructive such as sampling method which used 2 cm every interval 4 cm. The cluster analysis showed that deposition process seemed of one kind (88-0 cm) by nine variables. They are : main of grain size between clay to lower very fine sand, lightness sediment (L*) about 40,14-44,17, Magnetic Susceptibility (MS) about 13,60-116,70, biogenic carbonate (BC) by microscopic observation about 3-10%, carbonate about 17,36-50,17%, Total Organic Carbon (TOC) about 0,76-2,01%, C/N ratio about 9,11-13,57, ln K / Ti about 0,58-1,09, and ln Mn / Cl about -4,97- -4,24. Sediment character by Principal Component Analysis/PCA showed principle component/F1 as 28,10% indicated Magnetic Susceptibility (MS) and ln K/Ti and ln Mn/Cl were the main character of the Kangean Slope’s sediment and suggested to very strong influence from mainland.Keywords: vertically analysis, environmental changes, Indonesian throughflow, sediment character, principle component