Sedimentary Responses to Hydrological Changes During Paleogene Hy-Perthermals in the Eastern Tethyan Seas

The Paleogene period was characterized by several hyperthermal events, including the Early Late Paleocene Event (ELPE), Pre-Onset Excursion (POE), Paleocene–Eocene Thermal Maximum (PETM), Eocene Thermal Maximum 2 (ETM2), and the Early Eocene Climatic Optimum (EECO). These events serve as valuable deep-time analogs for understanding hydrological responses to anthropogenic warming. The Eastern Tethyan seas preserve critical sedimentary archives of these climatic perturbations. Here, we synthesize available marine records to assess hydrological changes, focusing on precipitation and runoff dynamics, storm activity, and sea-level fluctuations. The available evidence indicates that the hydrological cycle in the Eastern Tethys was strongly perturbed during early Paleogene hyperthermals, albeit with marked spatial heterogeneity. Along the Asian margin, siliciclastic input increased during the PETM, suggesting intensified terrestrial precipitation and erosion. In contrast, siliciclastic input decreased on the northern Indian margin and in the Tarim Basin, likely reflecting relative sea-level rise. Post-PETM sea-level evolution also differed regionally: the Tarim Basin maintained relatively high sea level, whereas the northern Indian margin experienced renewed sea-level fall. Furthermore, the Tarim Basin records pronounced storm activity during the POE, PETM, and ETM2, comparable to the northern Arabian margin, where storm-related calcareous turbidites occurred during the POE, PETM, and EECO. These hydrological perturbations were accompanied by enhanced continental weathering, increased nutrient supply, shifts in marine productivity, local oxygen depletion, and reorganization of carbonate platforms and marine biota. Overall, studies from the Eastern Tethyan seas demonstrate that early Paleogene hyperthermals involved not only extreme warming but also substantially intensified hydrological changes, expressed through coupled variations in rainfall, runoff, storm activity, and sea level under strong paleogeographic control.