## 5 Discussion
### Active Mantle Plume Groups  
The Great Igneous Province (GIP) formed rapidly during a specific period of geological history, characterized by large-scale intraplate magmatism sourced from the mantle. The GIP emerged during almost all significant rifting events. At the same time, the development of large igneous provinces is also well correlated with biological extinction events that occurred throughout geological history [29,30,50,51]. The expansion of the mantle plume caused uplift of the crust and geological modifications in sediment patterns. For instance, Neoproterozoic mantle plume activity uplifted the region around southern Australia and resulted in the formation of several kilometers deep canyons with sharp edges [30,43,44,45]. During the depositional period of the Maokou Formation, Emei mantle plume activity formed a dome-like uplift that was intermittently activated and led to an extensive sea recession. The current measured section shows sustained layer accumulation of carbonate slides in the Wordian order, indicating a gradual divergence of the palaeomorphic pattern. Additionally, the carbonate terrace gradually replaced the gently sloping slope of carbonate, and the C isotopes show a continuous negative drift in the mid-to-late Wordian order of the Upper Yangzi, which confirms extensive sea recession (Figure 13b). The formation and development ex situ carbonate clasts in Palazzo Adriano, Sicily, Italy--located near the equator--happened simultaneously during the same period [33,34]. According to petrographic features and elemental geochemistry  
Figure 12: Comparison of C isotopes during the Wordian stage and the Illawarra magnetic pole reversal time [20,40,44,46]. analysis, the active mantle plume at Emei produced a comparable sedimentary record before rifting, which is spread throughout the region. Figure 13: Tectonic-sedimentary pattern of the Guadalupian in the Yangzi plate. (**a**) Roadian order: relatively flat ancient landform. (**b**) Mid-late Wordian order: the plates began to break apart. (**c**) _J. postserata_ belt: deep hydrothermal fluids reached the moho surface, intensifying plate rifting. (**d**) _J. shannoni_ belt: mantle plumes arched upward, and the plate rose (**e**) _J. altudaensis_ belt: the plate split. During the Middle and Late Permian, the Paleotethys oceanic plate continued to subduct eastward along the Jinshajiang fracture zone, resulting in the expansion of the back-arc region [52]. In this context, the mantle heat plume at the core-mantle boundary rose dramatically [51]. The first extensive basaltic mafic overflow was recorded along the Yunnan-Nayong-Xifeng-Wengan area at 263 Ma [34]. This event occurred 2 Ma after the end of the Wordian order deposition. In the study area, the profiles in the study area recorded laminated and densely distributed flint nodules and flint strips, with obvious phase transitions in the early Capitanian (Figures 5 and 13c). The logging curves also recorded significantly increased GR and mud content (Figure 6). These findings indicate that in the early Capitanian, with the paleomagnetic inversion and continued activity of the Emei mantle plume, the degree of rifting in the Yangzi Zone further intensified, and paleomorphic differentiation became more obvious. In the late Capitanian, above the lower boundary of the _J. altudanensis_ zone, a thin layer of siliciclastic deposition can be observed in the section (Figures 4 and 13c). This indicates that rifting activity caused the sedimentary phase to be reduced to an undercompensated environment. As a result, a large amount of siliceous minerals, partly brought by volcanic eruptions, entered the paleo-ocean, where the temperature decreased, SiO\({}_{2}\) solubility decreased, and the siliceous matter reached the standard for siliciclastic deposition and was deposited to form the silica rock. The scale-forming sedimentary tuff bands observed in this field section occur at the base of the Lopingian (Figures 4 and 5), corresponding to the _C.