Bulletin of the Geological Society of Malaysia, Volume 65, June 2018, pp. 63 – 67
Department of Geosciences, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak, Malaysia
*Corresponding author email address: email@example.com
Abstract: Well studies have confirmed the presence of Quaternary sediments in both onshore and offshore areas near the township of Pekan in Pahang, while the Tertiary sediments are only found offshore. This could be well-explained through the palaeo-environmental evolution of the Tertiary sediments in Penyu Basin, where it started from continental (older sediments) to marine (younger sediments) environments, suggesting that transgression had occurred causing the Pahang River delta to be located where it is today. In fact, the presence of ancient river channels found in the Penyu Basin supports the transgression claim. Thus, to prove the possible extension of the basin, this paper aims to delineate the geometry of the basement at Pekan area, as well as to study the distribution of different basement rocks in the area by reconstructing the geo-lithological model of Pekan. Thirty (30) well data from previous work, conducted by the Jabatan Penyiasatan Kajibumi Malaysia in 1992 and 1993 were used to reconstruct the geo-lithological model. Utilizing the Lithoblending algorithm to reconstruct the model has allowed us to have a greater control on the model by using nearby well data to extend the lithology laterally, rather than extrapolating vertically below the boreholes, which can lead to inaccuracy in correlation. The outcome of the geo-lithological modelling revealed that the basin originates 5km from the present shoreline, deepens and widens towards the east, i.e. offshore area. In addition, two different types of basement rocks were identified in the area, namely weathered granite and metasediment. The contact between these two basement rocks, are found to be underlying the present-day Pahang River. The deepening and widening of the basement as well as the contact point between the basement rocks is interpreted as corresponding to the opening of the Penyu Basin.
Keywords: geo-lithological model, modelling, subsurface of Pekan, Penyu Basin