Electronic Theses and Dissertation

Kawasan pesisir merupakan wilayah yang dinamis dan menyimpan potensi sumber daya mineral, salah satunya pasir besi. Di Pantai Syiah Kuala, Banda Aceh, pasir besi diduga tersebar di bawah permukaan sebagai hasil proses sedimentasi dari laut dan darat. Meskipun beberapa penelitian sebelumnya telah mengidentifikasi kandungan mineral magnetit di daerah ini, namun belum ada kajian yang memetakan distribusi bawah permukaan secara detail. Oleh karena itu, penelitian ini dilakukan untuk mengidentifikasi keberadaan dan distribusi pasir besi bawah permukaan dengan menggunakan metode Ground Penetrating Radar (GPR). Metode GPR dipilih karena kemampuannya dalam mendeteksi variasi konstanta dielektrik antar lapisan tanah secara non-destruktif, cepat, dan dengan resolusi tinggi. Akuisisi data dilakukan pada lima lintasan dengan orientasi tegak lurus terhadap garis pantai menggunakan perangkat GPR IDS dengan antena frekuensi 80 MHz. Pengolahan data mencakup proses set zero time, dewow, remove mean trace, gain, dan migration, menggunakan perangkat lunak GPRPy. Hasil interpretasi radargram menunjukkan variasi pola refleksi elektromagnetik yang merepresentasikan perbedaan litologi bawah permukaan, seperti pasir kering, campuran pasir dengan pasir besi, serta zona jenuh air. Refleksi yang paralel, kuat, dan kontinu pada kedalaman 0 – 2 meter mengindikasikan adanya lapisan pasir besi yang tersebar.

Coastal areas are dynamic zones with considerable potential for mineral resources, including subsurface iron sand deposits. At Syiah Kuala Beach, Banda Aceh, iron sand is presumed to be distributed below the surface as a result of coastal and fluvial sedimentation processes. While previous studies have identified the presence of magnetite in this region, none have focused on mapping the subsurface distribution in detail. Therefore, this study aims to identify the presence and distribution of subsurface iron sand using the Ground Penetrating Radar (GPR) method. GPR was selected due to its ability to detect dielectric constant variations between soil layers in a non-destructive, rapid, and high-resolution manner. Data acquisition was conducted along five survey lines oriented perpendicular to the shoreline using an IDS GPR device with an 80 MHz antenna. Data processing involved several steps, including zero time setting, dewow, remove mean trace, gain, and migration, using the GPRPy software. The radargram interpretations revealed variations in electromagnetic reflection patterns, indicating differences in subsurface lithology, such as dry sand, iron-sand mixtures, and saturated zones. Strong, continuous, and parallel reflections at depths of 0 – 2 meters suggest the presence of a widespread iron sand layer. This study demonstrates that the GPR method is effective for preliminary exploration of coastal mineral resources and can serve as a reference for future sustainable geophysical surveys in similar environments.