Constraining the Permian-Triassic boundary in the Gua Panjang Hill, Merapoh, Pahang state, Malaysia

The search for the critical Permian-Triassic Boundary (PTB) in Malaysia focuses on limestone hills in the Lipis district since the 1990s. The recent paleontological findings at Gua Panjang hill in Merapoh, Pahang state, has constrained the presence of PTB to be between 6.50 m to 9.00 m from the base of the logged section at the eastern cliff. Late Permian foraminifera such as Colaniella sp., Ichtyofrondina sp., and Palaeotextularia sp. were observed 6.50 m from the base of the logged section, where the microfacies is characterized as bioclastic grainstone deposited within a shallow open shelf environment during Late Permian. Located 2.50 m above the Late Permian horizon is a highly dolomitized horizon with the presence of earliest Triassic conodonts such as Hindeodus parvus and Isarcicella staeschi. Between the height of 6.50 m and 9.00 m, analyses on δ13C and δ18O of the whole rock composition have shown slight decrease in both isotopes to 1.18‰ (VPDB) and 18.23‰ (SMOW), respectively. However, a negative carbon isotope excursion, which is the signature in most PTB sections worldwide, was not observed in the Gua Panjang limestone section potentially due to the large-spaced sampling. Therefore, a high precision research on the 10.00 m logged section at the eastern cliff of the Gua Panjang hill is crucial to identify the precise position of the first PTB in Malaysia.