Latitudinal Controls on Carbonate Factory Evolution Following the Carnian Pluvial Episode: Insights from the Tibetan Himalaya

The Carnian Pluvial Episode (CPE) is characterized by multiple negative carbon isotope excursions, generally attributed to massive CO2 emissions from the Wrangellia Large Igneous Province. The intense climatic and environmental perturbations during the CPE reorganized low-latitude carbonate factories, driving a shift from microbial-dominated systems to heterotrophic metazoan-dominated factories, followed by a post-CPE resurgence of microbial factories. However, this pattern is documented primarily in paleo-tropic regions (e.g., Italy and the Sichuan Basin), and its global relevance remains uncertain. Here, we present a new high-resolution dataset from the subtropical Tibetan Himalaya, combining carbonate microfacies analysis with conodont biostratigraphy, to reconstruct the evolution of carbonate platforms during the Late Carnian–Early Norian interval. Our results show that the Qulonggongba Formation (Tuvalian 2) was deposited in a mixed lagoonal environment influenced by terrigenous input, while the overlying Qimala Formation (Tuvalian 2–Lacian) developed in a middle-ramp to lagoonal environment affected by sea-level changes. After the CPE, the carbonate factory in the western Tibetan Himalaya shifted from a heterotrophic metazoan-dominated skeletal factory to a peloid-dominated factory. This heterogeneity in post-CPE factory types among Italy, the Sichuan Basin, and the Tibetan Himalaya is largely due to latitudinal controls on surface seawater temperature and carbonate saturation. Additionally, paleogeographic configurations further differentiated the recovery patterns: low-latitude tropical regions, commonly in semi-restricted settings, favored microbial factories, whereas the subtropical, open-marine conditions of the Tibetan Himalaya sustained heterotrophic metazoan dominance.