Electronic Theses and Dissertation

Penelitian ini menggunakan metode spektroskopi inframerah untuk menganalisis karakteristik spektra dan mengidentifikasi komposisi mineral sampel tanah yang diambil dari kawasan geotermal ie su’um dan ie jue. spektra reflektansi inframerah dari sampel tanah tersebut diukur menggunakan spektrometer fieldspec4 hi-res dari panjang gelombang visible and near-infrared (vnir; 350-1000 nm) sampai shortwave infrared (swir; 1000-2500 nm). komposisi mineral diidentifikasi dengan menganalisa kemiripan karakteristik spektra hasil pengukuran dengan database spektra mineral menggunakan metode spectra angle mapper (sam), spectra feature fitting (sff), dan binary encoding (be). hasil penelitian menunjukkan bahwa karakteristik spektra sampel tanah dari kawasan geotermal ie su’um dan ie jue memiliki posisi panjang gelombang, intensitas reflektansi, dan bentuk fitur absorpsi yang berbeda-beda. hal ini disebabkan karena perbedaan komposisi mineral dan ukuran butir sampel tanah ie su’um dan ie jue. komposisi mineral sampel tanah dari kawasan geotermal tersebut didominasi oleh kelompok mineral phyllosilicate. sampel tanah ie su’um didominasi oleh mineral illite (sampel is 01-is 04, is 07, dam is 08). sampel tanah ie jue didominasi oleh mineral montmorillonite (sampel ij 02, dan ij 04-ij 08) dan kaolinite dengan campuran smectite (sampel ij 01 dan ij 03). mineral phyllosilicate ini memiliki ciri khas fitur absorbsi pada panjang gelombang 2200 nm yang disebabkan oleh proses vibrasi molekul al-oh. khusus untuk sampel tanah ie su’um (sampel is 05 dan is 06) ditemukan mineral ferrihydrite, yang memiliki ciri khas fitur absorpsi pada panjang gelombang 1000 nm yang disebabkan oleh proses elektronik ion fe3+. berdasarkan penelitian ini dapat disimpulkan bahwa metode spektroskopi inframerah dapat mengidentifikasi komposisi mineral tanah yang diambil dari kawasan geotermal. kata kunci: kawasan geotermal, spektroskopi inframerah, tanah, komposisi mineral, ie su’um, ie jue

This study uses infrared spectroscopy method to analyze the spectral characteristics and identify the mineral composition of soil samples taken from the Ie Su'um and Ie Jue geothermal areas. The infrared reflectance spectra of the soil samples were measured using a FieldSpec4 Hi-Res Spectrometer from visible and near-infrared (VNIR; 350-1000 nm) to shortwave infrared (SWIR; 1000-2500 nm) wavelength ranges. Mineral compositions were identified by analyzing the similarity of the characteristics of measured spectra with mineral spectra database using the Spectra Angle Mapper (SAM), Spectra Feature Fitting (SFF), and Binary Encoding (BE) methods. The results showed that the spectral characteristics of soil samples from the Ie Su'um and Ie Jue geothermal areas have different wavelength positions, reflectance intensities, and shapes of absorption features. This is due to differences in mineral compositions and grain sizes of the soil samples. The mineral compositions of the soil samples from the geothermal area were dominated by the phyllosilicate minerals. Ie Su'um soil samples dominated by illite (Samples IS 01-IS 04, IS 07, and IS 08). Ie Jue soil samples were dominated by montmorillonite (Samples IJ 02, and IJ 04-IJ 08) and kaolinite with a mixture of smectite (Samples IJ 01 and IJ 03). These phyllosilicate minerals have characteristic absorption features at a wavelength of 2200 nm caused by the vibrational process of Al-OH molecule. The Ie Su'um soil samples were also found ferrihydrite (Samples IS 05 and IS 06), which has characteristic absorption features at a wavelength of 1000 nm caused by the electronic process of Fe3+ ions. Based on this research, it can be concluded that the infrared spectroscopy method can identify mineral composition of soil taken from the geothermal area. Keywords: Geothermal Area, Infrared Spectroscopy, Soil, Mineral Composition, Ie Su'um, Ie Jue