Turkish Journal of Earth Sciences Turkish J Earth Sci (2017) 26: 377-394 http://journals.tubitak.gov.tr/earth/ © TÜBİTAK Research Article doi:10.3906/yer-1612-29 Higher-resolution biostratigraphy for the Kinta Limestone and an implication for continuous sedimentation in the Paleo-Tethys, Western Belt of Peninsular Malaysia 1,2, 2 3 4 2 5 Haylay TSEGAB *, Chow Weng SUM , Gatovsky A. YURIY , Aaron W. HUNTER , Jasmi AB TALIB , Solomon KASSA 1 South-East Asia Carbonate Research Laboratory (SEACaRL), Department of Geosciences, Faculty of Geosciences and Petroleum Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia 2 Department of Geosciences, Faculty of Geosciences and Petroleum Engineering, Universiti Teknologi PETRONAS, Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia 3 Lomonosov Moscow State University, Moscow, Russian Federation 4 Department of Applied Geology, Western Australian School of Mines, Curtin University, Perth, Australia 5 Department of Applied Geology, School of Applied Natural Sciences, Adama Sciences and Technology University, Adama, Ethiopia Received: 29.12.2016 Accepted/Published Online: 21.09.2017 Final Version: 13.11.2017 Abstract: The paleogeography of the juxtaposed Southeast Asian terranes, derived from the northeastern margins of Gondwana during the Carboniferous to Triassic, resulted in complex basin evolution with massive carbonate deposition on the margins of the Paleo- Tethys. Due to the inherited structural and tectonothermal complexities, discovery of diagnostic microfossils from these carbonates has been problematic. This is particularly the case for the Kinta Limestone, a massive Paleozoic carbonate succession that covers most of the Kinta Valley in the central part of the Western Belt of Peninsular Malaysia. Owing to the complex structural and igneous events, as well as extensive diagenetic alterations, establishing precise age constraints for these carbonates has been challenging. Furthermore, the sedimentation history of these deposits has been masked. Three boreholes, totaling 360 m thickness of core, were drilled at either end of the Kinta Valley on a north-south transect through sections with minimal thermal alteration. The sections are composed chiefly of carbonaceous carbonate mudstone with shale and siltstones beds, in which the carbonates were sampled for microfossils. Five hundred conodont elements were extracted. Nine diagnostic conodont genera and 28 age diagnostic conodont species were identified. The identification of Pseudopolygnathus triangulus triangulus and Declinognathodus noduliferus noduliferus indicated that the successions ranged from Upper Devonian to upper Carboniferous. Further analysis and establishment of stage-level datum that range from the Famennian to Bashkirian (Late Carboniferous) enabled detection of continuous sedimentation and improved age constraints in undated sections of the Kinta Limestone. This higher-resolution conodont biostratigraphy suggests a prevalence of continuous carbonate deposition during the Early Devonian to Late Carboniferous in the Paleo-Tethys. Thus, the identification of diagnostic conodont species for the first time from subsurface data in the area has helped improve the biostratigraphic resolution and establishes depositional continuity of the Kinta Limestone. These data could provide clues to the Paleo-Tethys paleogeographic reconstruction and paleodepositional conditions, and could establish higher temporal resolution correlation than previously attempted. Key words: Carbonate, conodont, higher-resolution, correlation, paleogeography 1. Introduction The Paleozoic stratigraphic record of Peninsular The Devonian to Carboniferous of Southeast Asia Malaysia, where many carbonate occurrences have was dominated by carbonate deposition from shallow been reported (Figure 1), is not an exception. These continental to deeper waters of the Paleo-Tethys deposits encompass marine sedimentary successions (Metcalfe, 2002; Jian et al., 2009a, 2009b). Paleogeographic ranging from the late Cambrian to early Permian (Foo, reconstructions of this region (Metcalfe et al., 1990; 1983; Lee, 2009). Complex tectonostratigraphic events Metcalfe, 2011, 2013; Searle et al., 2012) have shown, of the Paleo-Tethys basins have been well documented using paleontological, paleobiogeographical, and by Metcalfe and Irving (1990), Alavi (1991), Hutchison tectonostratigraphic datasets, that the Paleo-Tethys had (1994, 1996, 2007), Metcalfe et al. (2011), and Metcalfe huge accommodation space, which probably resulted in (2013). Thus, these complicated paleodepositional settings the deposition of massive carbonates in the Paleozoic. may have influenced the distribution and abundance of * Correspondence: [email protected] 377 TSEGAB et al. / Turkish J Earth Sci Figure 1. Map showing the study area in Peninsular Malaysia, Southeast Asia region. The study area is marked by the red box in western Malaysia. microfossils, which are among the key datasets required to have still been preserved (Suntharalingam, 1968; Fontaine understand the Paleo-Tethys depositional environments, and Ibrahim, 1995; Haylay et al., 2013). Ingham et al. sedimentation histories, and biostratigraphy. (1960), Lee (2009), and (Richardson, 1946) documented To date, high-resolution conodont biostratigraphy that the limestone close to the intrusive batholith lacked of Peninsular Malaysia has focused mainly on the fossils and is invariably marmorized, implying that northwestern part of the Western Stratigraphic Belt as paleontological data from outcrops nearer to the granitic this part of the peninsula contains an almost complete intrusion might be affected by structural and thermal stratigraphic succession of Paleozoic strata (Lee et al., 2004; events. This has negatively impacted our understanding Cocks et al., 2005; Meor et al., 2005; Lee, 2009; Bashardin of the biostratigraphy and deposition history in the et al., 2014), is relatively fossiliferous, and is less affected Kinta Valley successions and resulted in widely variable by metamorphism (Lee, 2009). Conversely, the current age constraints as detailed below. The outcrop-based biostratigraphy of the Kinta Limestone, which is the main dating showed that the limestones to the north are carbonate lithological unit found within the Kinta Valley, mixed Devonian to Carboniferous (Metcalfe, 2002); the in the central part of the Western Belt, is based solely on limestones further to the southern tip of the valley are some poorly preserved uncommon microfossils recovered middle Devonian to middle Permian (Suntharalingam, from outcrop samples within highly metamorphosed 1968). Among the pioneer workers on biostratigraphic sections (Suntharalingam, 1968; Lane, 1979; Lane et al., studies in the Kinta Valley, Gobbett (1968), who found 1979; Fontaine et al., 1995; Fontaine, 2002; Metcalfe, 2002) fusulinacean foraminifera, and Suntharalingam (1968), (Figure 2). who identified mollusks and tabulate corals from tin- Despite the Kinta Limestone and associated mine outcrops, determined the age of the successions as siliciclastic lithologies having been affected by multiple middle Devonian to middle Permian. Contributions from alterations such as diagenesis, structural deformation, and Fontaine and Ibrahim (1995) also confirmed a Permian metamorphism, important and informative microfossils age section from western Kampar in the southern part 378 TSEGAB et al. / Turkish J Earth Sci Figure 2. Map of the study area showing the Kinta Valley in the Peninsular Malaysia. Note that drilling locations are in the north (Sungai Siput) and in the south (Malim Nawar). of the Kinta Valley using Maklaya (fusuline). Lane et were patchy and all age constraints were made based only al. (1979) and Metcalfe (2002) introduced conodont on data derived from specific outcrops. Some of them even dating from a metamorphosed limestone outcrop in the showed diverse age ranges for groups of microfossils in a Kanthan area, which has been dated as mixed Devonian single section (Metcalfe, 2002), which may indicate how to Carboniferous in age. These studies have advanced the complex it was to establish constrained paleontological stratigraphic understanding of the Kinta Limestone, as dating of the sedimentary successions let alone understand they introduced the usage of microfossils from different the depositional history of the succession. The impact of geographical localities and they attempted to establish the tectonothermal effects in the late Permian and Early to local and regional correlations as well. However, a middle Cretaceous (Harbury et al., 1990) has also affected thorough review of the previous micropaleontological the reliability of the aragonitic, calcitic, and siliceous works on the Kinta Limestone showed that these efforts microfossils for dating and understanding the depositional 379 TSEGAB et al. / Turkish J Earth Sci history in the basin. Thus, the existing paleontological as pinching out black shale and silt beds, particularly in dating has been thwarted by poor preservation and the Upper Devonian to lower Carboniferous intervals crystallization of the microfossils, which in turn hindered (Haylay et al., 2015). The Kinta Limestone is bounded on identification of taxa to the species level. top by an erosional unconformity and the lower boundary Despite the many attempts to date the Kinta Limestone is unknown, except for speculative older Precambrian on the basis of outcrop studies, microfossil distributions in basement complexes.