The Upper Permian to Middle Triassic strata are extensively exposed in both North and South China, encompassing a wide range of sedimentary environments. Lower Triassic successions are particularly well developed across the South China Block (Benton et al. 2013), which was situated within the tropical zone of the eastern Palaeotethys Ocean during the Permian-Triassic transition (Fig. 2.1). During the Early and Middle Triassic, the central part of the South China Block was dominated by the expansive Yangtze Platform (Wang 1985), a massive carbonate platform flanked by distal ramp to shelf-basin settings to the north and south. The southern margin, now referred to as the Nanpanjiang Basin, represents a deep-water basin environment (Feng et al. 1997). In platform settings, the earliest Triassic was characterized by the deposition of massive limestones, which transitioned to thin-bedded lime mudstones during the Olenekian and Middle Triassic. In contrast, basin facies from the Griesbachian interval were marked by alternating black shales and calcareous mudstones, while siliciclastic mudstones and turbidites dominated Olenekian deposits (Lehrmann et al. 2015). Intermediate ramp settings, located between shallow-platform and deep-basin environments, typically feature thick successions of thin-bedded argillaceous limestones and calcareous mudstones (Liu and Xu 1994; Yin et al. 1995, 2001; Zhao et al. 2007, 2013; Ma et al. 2009). Within the Nanpanjiang Basin, several isolated Early–Middle Triassic platforms are prominent, including the Great Bank of Guizhou, which was particularly well-preserved and conspicuous in the field (Lehrmann et al. 1998, 2007). The marine successions spanning the uppermost Permian to Middle Triassic are exceptionally complete across these palaeogeographical settings and are continuously exposed, providing an excellent record of this critical interval in Earth’s history (Ji et al. 2011; Jiang et al. 2007, 2011, 2014; Hu et al. 2011; Yan et al. 2013, 2015).