Electronic Theses and Dissertation

Abstrak pemetaan geologi dan studi kedalaman muka air tanah dilakukan di kecamatan peukan bada dan kecamatan lhoknga, kabupaten aceh besar, dengan luas daerah penelitian sekitar ±25 km². secara geografis, wilayah penelitian berada diantara daerah pesisir dan perbukitan yang memiliki variasi bentang alam serta kondisi geologi yang kompleks. berdasarkan peta geologi regional lembar banda aceh (bennett dkk., 1981), daerah penelitian tersusun oleh beberapa satuan geologi, yaitu formasi lhoknga (mul) yang berumur jura hingga kapur, formasi raba (murlr) dengan umur jura hingga kapur dan , serta endapan aluvial kuarter (qh) yang berkembang pada daerah dataran rendah dan pesisir. penelitian ini bertujuan untuk mengetahui kondisi geologi permukaan yang meliputi litologi, geomorfologi, dan struktur geologi, serta mengkaji kedalaman muka air tanah berdasarkan kondisi geologi dan karakter bawah permukaan. metode yang digunakan dalam penelitian ini meliputi pemetaan geologi permukaan melalui pengamatan langsung di lapangan, pengukuran struktur geologi, serta pengambilan data pendukung hidrogeologi. selain itu, dilakukan pengukuran kedalaman muka air tanah pada sumur gali masyarakat dan pengukuran geolistrik untuk mengidentifikasi lapisan bawah permukaan yang berpotensi sebagai akuifer. berdasarkan hasil penelitian terdapat 3 satuan, yaitu satuan batugamping raba (murlr), satuan batu serpih (mul), dan satuan endapan alluvium (qh). litologi yang ditemukan di lapangan berupa batugamping terumbu, batugamping tipis, batuserpih, mineral kalsit, kelabu pejal, dan endapan lempung pasiran. sedangkan kondisi bentang alam terdiri atas satuan bentuk lahan denudasional (d5), satuan bentuk lahan struktural (s1), dan satuan bentuk lahan fluvial (f1, f3, f4). berdasarkan hasil pola aliran yaitu pola aliran dendritik dengan kategori sungai berstadia tua. berdasarkan hasil analisis petrografi dari ke 2 sampel, pada batugamping terumbu formasi raba dinamakan crystalline carbonate. sedangkan pada batuserpih formasi lhoknga dinamakan packstone. dari hasil analisis kedalaman muka air tanah yang menggunakan metode geolistrik 1d pada titik pengukuran ves 1 memiliki nilai resistivitas berkisar antara 0,2 Ωm hingga 4,6 Ωm. sedangkan pada titik pengukuran ves 2 memiliki nilai resistivitas berkisar antara 0,0 Ωm hingga 7,1 Ωm. kata kunci: pemetaan geologi, peukan bada, crystalline carbonate, packstone, geolistrik 1d.

ABSTRACT Geological mapping and groundwater depth studies were carried out in Peukan Bada and Lhoknga Districts, Aceh Besar Regency, with a research area of about ±25 km². Geographically, the research area is located between coastal and hilly areas that have a variety of landscapes and complex geological conditions. Based on the Regional Geological Map of the Banda Aceh Sheet (Bennett et al., 1981), the research area is composed of several geological units, namely the Lhoknga Formation (Mul) which is jura to limestone age, the Raba Formation (Murlr) with jura to limestone age and, as well as quaternary alluvial deposits (Qh) that develop in lowland and coastal areas. This study aims to determine the geological conditions of the surface which includes lithology, geomorphology, and geological structure, as well as to examine the depth of the groundwater table based on geological conditions and subsurface characteristics. The methods used in this study include surface geological mapping through direct observation in the field, measurement of geological structures, and collection of hydrogeological supporting data. In addition, groundwater depth measurements were carried out in community wells and geoelectric measurements were carried out to identify subsurface layers that have the potential to be aquifers. Based on the results of the study, there are 3 units, namely the palpable limestone unit (Murlr), the shale unit (Mul), and the alluvium deposit unit (Qh). The lithology found in the field is in the form of reef limestone, thin limestone, silica limestone, calcite minerals, solid gray, and sandy clay deposits. Meanwhile, landscape conditions consist of denunciation land form units (D5), structural land form units (S1), and fluvial land form units (F1, F3, F4). Based on the results of the flow pattern, namely the dendritic flow pattern with the category of old stadia rivers. Based on the results of petrographic analysis from the 2 samples, the reef limestone of the Raba Formation is called crystalline carbonate. Meanwhile, the Lhoknga Formation is called packstone. From the results of the groundwater level depth analysis using the 1D geoelectric method at the VES 1 measurement point, the resistivity value ranges from 0.2 Ωm to 3,3 Ωm. Meanwhile, the measurement point VES 2 has a resistivity value ranging from 0.0 Ωm to 2.7 Ωm. Keywords: Geological Mapping, Peukan Bada, Crystalline Carbonate, Packstone, 1D Geoelectrical.