Identification of peat layer thickness in Sungai Tabuk District, Banjar Regency, South Kalimantan, has been conducted using the 2D geoelectrical resistivity method with the Wenner configuration. The purpose of this study is to establish the model of 2D resistivity cross section and to analyze the lithology types, depth and thickness of peat layers in the study area. Data acquisition was carried out on three survey lines with a length of 40 meters each and 1 meter electrode spacing. Data processing using Res2Dinv software produced 2D resistivity cross-sections with RMS errors of 4.8%, 5.1%, and 5.6% for each line, respectively. The results show that the subsurface layers in Abumbun Jaya Village consist of two lithology types: peat layer and clay layer. The peat layer has resistivity values of 17.8-231 Ωm with varying thicknesses of 1.5 meters on line 1, 3.11 meters on line 2, and 1.92 meters on line 3. The clay layer has resistivity values of 0.583-17.8 Ωm with a depth of up to 6.25 meters. Based on Febriana's research (2024) at the same location, the peat in the study area is classified as sapric peat with water content of 54.1%-119.8%, bulk density of 0.32-0.46 gr/cm³, and porosity of 42.1%-46%. The variation in peat thickness between survey lines indicates that the sedimentation and organic matter accumulation processes in the study area are uneven, with line 2 having the greatest thickness due to its location in a depression area. This information can be used as a reference for infrastructure development planning on peatland.

Keywords: 2D Geoelectrical, Wenner Configuration, Peat Thickness, Resistivity, Sungai Tabuk