INVESTIGATION OF SEDIMENTARY OUTCROPS USING GEOPHYSICAL METHODS IN LANGKAWI, KEDAH, MALAYSIA

The geological outcrop provides insight into the subsurface characteristics and history of the region. Traditional mapping and sampling techniques offer surface information but lack comprehensive subsurface analysis. To bridge this gap, 2-D Seismic Refraction and 2-D Electrical Resistivity Imaging (2-D ERI) methods were applied at Sungai Itau and Taman Helang Perdana in Langkawi, Kedah, Malaysia. These sites, part of the Singa Formation, consist of sandstone, carbonate, mudstone, and conglomerate. The study aimed to map the outcrop and determine the seismic velocity and resistivity values of the formations. Rock samples underwent thin-section and XRD analysis. Results showed sandstone had high velocity (1000–4500 m/s) and resistivity (1000–6000 Ωm), while mudstone exhibited lower values (500–2500 m/s; 20–120 Ωm). Sandstone was rich in quartz, with microcline, hematite, and dolomite. The integration of seismic, resistivity, and laboratory analyses effectively characterized the subsurface, confirming the Singa Formation’s presence. This study enhances geological maps by combining surface observations with subsurface data, leading to a more comprehensive understanding of the geological setting for scientific, engineering, and environmental applications.