A Contemporary Review of Sedimentological and Stratigraphic
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Bulletin of the Geological Society of Malaysia, Volume 69, May 2020, pp. 53 - 65 DOI: https://doi.org/10.7186/bgsm69202005 A contemporary review of sedimentological and stratigraphic framework of the Late Paleogene deep marine sedimentary successions of West Sabah, North-West Borneo Muhammad Jamil1,2,*, Abdul Hadi Abd Rahman1, Numair Ahmed Siddiqui1, Noor Azahar Ibrahim1, Nisar Ahmed1 1 Department of Geosciences, Universiti Teknologi PETRONAS (UTP), 32610 Seri Iskandar, Perak D.R., Malaysia 2 Department of Earth Sciences, COMSATS University Islamabad (CUI), 22060 Abbottabad, KPK, Pakistan * Corresponding author email address: [email protected] Abstract: A timely and updated review of the Late Paleogene deep marine sedimentary successions is vital for a better understanding of the historical advances in sedimentology and stratigraphic evolution of West Sabah. The main objective of the study is to discuss the facies characteristics and depositional environment of the Late Paleogene rock formations. In addition, the stratigraphic aspects of the Paleogene interval will also be discussed. The Oligocene Temburong Formation exposed in several localities of West Sabah had been field researched with varying depositional processes and facies analysis. Moreover, the distribution of submarine fan, the observed variety of deep marine sediments associated with various sedimentary processes and the source of sediments of the co-eval West Crocker Formation were also investigated with contorted layers of mass transport deposits (MTD) reported first time in the formation. The upper and lower stratigraphic contacts of Late Paleogene formations, the age of individual rock formations and use of the term “Crocker Formation” in the literature are discussed with numerous unconformities and their stratigraphic positions in the Paleogene interval have been incorporated to understand the historical development of the Paleogene stratigraphy of the West Sabah. Owing to degrading tropical climate of the area, there are limitations and constraints on field-based research where the older outcrops are altered with housing development and dense vegetative cover. This review outlined the scientific developments and highlighted the ambiguities associated with stratigraphic placement of the Temburong and Crocker formations that still needed to be resolved to get an upgraded depiction of the Late Paleogene sediments of West Sabah. Keywords: West Sabah, Late Paleogene, sedimentology, stratigraphic framework, Crocker Formation, Temburong Formation INTRODUCTION geoscientific research. The present review emphasizes on Sabah is situated in northern part of Borneo and is sedimentological and stratigraphic data to highlight the bounded by Sulu Sea in the East and South China Sea research questions and future academic pathways to resolve in the West (Figure 1A). The present study focuses on the geology of Late Paleogene sediments of West Sabah. the sedimentary successions and stratigraphic framework The Paleogene sedimentary successions exposed in of the West Sabah (Figure 1B) The Paleogene sediments West Sabah are divided into Early and Late Paleogene of West Sabah are the oldest sedimentary rocks which stratigraphic units. Early Paleogene units are the Trusmadi lie stratigraphically above the Cretaceous basement. To and East Crocker formations while the West Crocker and date, more work had been done for the younger Neogene Temburong formations are of Late Paleogene age (Figure rocks, and research is less focused on the older Paleogene 2). Trusmadi and East Crocker formations represent the successions. The quest for new exploration opportunity eastward continuation of Crocker-Rajang Group that was in offshore Sabah has enhanced the chance to find out metamorphosed, folded and uplifted (Tongkul, 1995; William more petroleum plays particularly in the older Paleogene et al., 2003). Early Paleogene successions were deposited, sedimentary sequence. Therefore, a better understanding and later weathered and re-sedimented to form the younger of deep marine Paleogene successions is needed for future sedimentary successions including the West Crocker and hydrocarbon exploration. Although, the available literature Temburong formations of Oligocene to Early Miocene age related to these Paleogene sediments discussed various (Tongkul, 1995; Crevello, 2002). aspects of sedimentology and stratigraphic framework, yet An integrated sedimentological and stratigraphic the review of published data is essential in order to discover understanding of these Late Paleogene deposits is still the pathways for bridging the research gaps. In addition, deficient. The West Crocker Formation had been well the study will reveal uncertainties and ambiguities present studied due to exposed outcrops and competent lithology in the literature and advance our understanding for future of massive sand units while the Temburong Formation is 0126-6187; 2637-109X / © 2020 Geological Society of Malaysia. All rights reserved. Muhammad Jamil, Abdul Hadi Abd Rahman, Numair Ahmed Siddiqui, Noor Azahar Ibrahim, Nisar Ahmed Figure 1: Regional map of Sabah (A) where South China Sea is present on the West of Sabah and Sulu Sea marks the eastern boundary. The location map of the study area is marked in white box (with B). Telipok is sited in NW Sabah while Jalan Pengalat Lok Kawi (JLK) and Kawang (KWN) is situated near Papar in SW Sabah (B). The study area includes the siliciclastic outcrops of Late Paleogene sedimentary sequences. less studied owing to incompetent lithologies like shales, characteristics of the facies, facies associations and depositional mudstones and siltstones which are more readily weathered model of the West Crocker and Temburong formations exposed and eroded. Furthermore, these argillaceous lithologies in West Sabah have not been clearly defined and differentiated; are readily covered with vegetation which consequently 2) The proposed stratigraphic framework has been described by hinders detailed field studies. However, new infrastructure numerous and sometimes conflicting terms like Deep Regional developments including the Pan Borneo Highway (also Unconformity (DRU), Top Crocker Unconformity (TCU), Late termed as Trans-Borneo Highway) construction work Eocene Unconformity (LEU), Base Miocene Unconformity resulted in many new sections for a better understanding (BMU) and Early Miocene Unconformity (EMU) (Figure of the Late Paleogene strata. 2). The nomenclature of various unconformities and their ages within Paleogene strata mentioned in the literature is FOCUS AND AREA OF THE STUDY perplexing and multifaceted (Jamil et al., 2019; Lunt, 2019). The available data and interpreted geology to date are The present study aims to review the sedimentological and noticeably marked by numerous uncertainties, confusions and stratigraphic framework of Late Paleogene sedimentary assumptions. The major uncertainties include: 1) The detailed successions of West Sabah. 54 Bulletin of the Geological Society of Malaysia, Volume 69, May 2020 A contemporary review of sedimentological and stratigraphic framework SEDIMENTOLOGY AND DEPOSITIONAL These heterogeneities impose a great challenge in order to SETTINGS understand the submarine fan environment and depositional There exists a great variety of the sedimentary processes settings. Nevertheless, these divergences contribute to prevalent in the marine depositional settings which are a variety of sedimentary processes and depositional largely attributed for the vertical and lateral heterogeneities environments interpreted for each type of sedimentary unit. in the sedimentary successions (Siddiqui et al., 2016; 2020) The sedimentary features and related processes which are associated with the Late Paleogene sediments are discussed in this review. Temburong Formation The flysch sediments of siltstone and shale were first assigned the name of Temburong Formation by Wilson (1964). The Temburong Formation is mainly composed of argillaceous units with calcareous shale in common (Hutchison, 1996). This formation is believed to be the representative of deep marine low energy environment. (Wilson, 1964; Bakar et al., 2017). Sedimentary facies Madon (1997) reported the argillaceous Temburong Figure 2: Generalized Formation having thin sandstone units interbedded with stratigraphy of West Sabah (Jackson et al., 2009). shale and siltstones in Labuan, Sabah. The Temburong Trusmadi and East Crocker Formation in Tenom area and Klias Peninsula, SW Sabah formations represent the is principally containing fine-grained turbidites (Td and Early Paleogene deposition Te Bouma Sequence), which are representative of basin whereas West Crocker and plain facies and was interpreted as the distal part of a deep Temburong formations marine fan (Asis et al., 2015; 2018). Abdullah et al. (2017) are of Oligocene to Early described the Temburong Formation as deep marine shale Miocene age. The Late and sandstone units located in Sipitang-Tenom area of Eocene Unconformity (LEU) West Sabah. Leong et al. (2018a) described fine grained separates the Early and Late Paleogene stratigraphic Temburong facies as Tc-Te Bouma divisions which are units. The upper contact suggestive of the distal lobe deposition of deep marine of Paleogene formations is outer fan while at some localities the formation has only marked with Base Miocene Te facies which represent the basin plain settings (Table 1). Unconformity (BMU). However, Jackson & Johnson (2009) interpreted that the Table 1: Sedimentary facies and depositional