Discovery of Late Carboniferous (moscovian) Coral Reefs in the North Qiangtang Terrane

The extreme climatic upheavals and high-frequency sea-level fluctuations during the Late Paleozoic Ice Age (LPIA) profoundly influenced the evolutionary trajectory of global marine ecosystems. During the Late Carboniferous Moscovian Age, driven by massive glacial expansion and a sharp increase in ecological stress, metazoan skeletal reefs experienced a significant global decline. Although existing studies indicate the development of a few small-scale coral reef complexes—symbiotic with sponges and other reef-building organisms—in low- to mid-latitude regions during this period, records of large-scale coral reefs are extremely rare in coeval strata worldwide. Currently, research on Late Carboniferous reefs primarily focuses on phylloid algal mounds and microbial buildups in regions such as North America and Europe. The traditional consensus maintains that Moscovian climate changes suppressed the reef-building capacity of metazoans. However, this conventional view, largely stemming from a sparse fossil record, has restricted our understanding of the actual presence and dynamics of reef-building communities under icehouse conditions. This study reports for the first time a well-preserved, large-scale Late Carboniferous coral reef succession discovered in the North Qiangtang Terrane. Fusulinid biostratigraphic evidence assigns this succession to the Moscovian stage. To elucidate the developmental mechanisms of the reef, a systematic carbonate microfacies analysis was conducted on the section, characterizing its internal architecture and petrological features, and preliminarily reconstructing its sedimentary evolution and paleoenvironment. This study thus provides a critical record for understanding the sedimentary processes and evolutionary mechanisms of regional reefs under an icehouse climatic background.