Search

Langkawi lies within the North-western Domain of Western Belt of Peninsular Malaysia which belongs to Sundaland and is composed of Palaeozoic sedimentary rocks, varying from the Cambrian to the Permian in age; Machinchang, Setul, Singa, and Chuping formations. Understanding the sediment depositional setting is a fundamental process in providing necessary information regarding the area's geologic history. The study's significance is to emphasize that the sedimentology, stratigraphy, and depositional environment must become the focal point of the inter-disciplinary research necessary to advance our understanding of the complex behaviors of the Earth. Updating and improving the sedimentary facies is vital to establishing a precise chronology of past events by completing the sedimentary sequences. The study involved the analysis of three sedimentary logs recorded within exposed rock sections of the Machinchang Formation in Langkawi. All sedimentary logs were then correlated to getting a composite log representing the entire succession sequence. The facies analysis belonging to Machinchang Formation shows the presence of nine facies types (F1 to F9) for this succession which can be assigned to four facies associations; tidal flat (FA1) represented by F1, F2, F3 and F4, upper shoreface (FA2) represents by F1 and F6, lower shoreface (FA3) represented by F1, F2 and F5 and foreshore (FA4) are represented by F1, F2, F7, F8 and F9. These sediments represent clastic types deposited in a shallow marine environment during a relatively short regression period. • Machinchang Formation is perhaps the best described Cambrian formation in Malaysia. • Machinchang Formation consists of three members; Hulor, Chinchin, and Tengkorak. • Update the sedimentary facies is vital to create a precise chronology of past events. • Sedimentology must become the focus to understand the complex process of the Earth. [ABSTRACT FROM AUTHOR]

Geophysical investigations are indirect methods of characterization of subsurface materials. Detailed information about the underlying subsurface is essential in preventing foundation failure and comprehending ground conditions. Seismic refraction is the most commonly used method for site characterization. Most researchers use this method with borehole data to investigate the subsurface. However, it is not adequate to rely on one method. To achieve an optimum result, it is best to apply different techniques and, as far as possible, integrate their results. The research aims to identify the shallow subsurface using geophysical techniques, correlate the results with the borehole data, estimate the rippability of rocks based on seismic velocity, and recommend a suitable foundation depth. 2D resistivity and seismic refraction methods were employed. Results show two resistivity zones. The lower resistivity zone (1–700 Ωm) comprises the loose and weathered zone, and the higher resistivity zone (700–4000 Ωm) indicates a more competent and compacted zone. The seismic interpretation reveals three subsurface layers. The first layer has an average velocity of 300–1600 m/s, indicating loose and unconsolidated soil with low N-values. The second layer (1600–2900 m/s) is interpreted as a stiffer and more competent layer. The third layer (2900–3800 m/s) is the most competent layer characterised by its high stiffness, and high N-values. The depth of rippable materials changes across sections, ranging from subsurface to a depth of 5 m. A marginal zone between rippable and non-rippable materials exists at a depth of 5–13 m. Non-rippable materials are below the depth of 13 m. The combined approaches' findings indicate that the area has the sufficient bearing capacity and is acceptable for construction; this will be considered when designing and constructing structures. • Geophysical investigations are indirect methods. • When the subsurface is not competent, buildings can collapse or fail. • Occurrence of a substantial layer of clay and can lead to structural failure. • Building foundations must rest conformably on non rippable layer. [ABSTRACT FROM AUTHOR]

Due to limited information, this paper aims to present a detailed facies analysis and depositional environment of the Carboniferous age, Singa Formation at Pulau Ular, Langkawi, Kedah. One exposed outcrop at Hill C was examined in detail, and one sedimentary log was created. The log is categorized bed by bed into several facies according to lithology and sedimentary structures. The focus was to identify the facies succession and to analyze the depositional environment as Singa Formation. This study is vital to reconstructing the pattern of past glacial as it will provide the crucial link between glacial processes and history, ice masses, and a more comprehensive Earth system. The Singa Formation is concluded into coarsening upward facies successions based on the facies succession grades upward from offshore facies. The depositional environment of Pulau Ular is interpreted as a coastal and a glacier depositional environment. Eight facies have been recognized; shale (FC1), shale with burrows (FC2), siltstone (FC3), shale with burrows, clay to silt (FC4), laminated shale with dropstone (FC5), sandstone that consists of dropstone (FC6), shale consists of dropstone (FC7) and sandstone with diamictite rock (FC8). Facies shale, sandstone, and siltstone proved that the study area is a coastal depositional environment, while facies consisting of dropstones and diamictite show that the study area is a glacier depositional environment. • To give a detailed facies analysis and depositional setting of the Singa Formation. • The Singa Formation is best seen in the exposed rock of Langkawi and north Perlis. • The Singa Formation consists of four members: Rebak, Kentut, Ular and Selang. • The facies of Pulau Ular indicate a coastal environment and glacial marine deposits. [ABSTRACT FROM AUTHOR]