Tracing the End‐Permian Floral Transition Through Palynofossils From the Gungri Formation, Spiti Basin, Tethyan Himalaya: Biostratigraphic Framework and Palaeovegetational Dynamics

ABSTRACT

Permian terrestrial vegetation exhibits a high degree of provincialism, reflecting strong latitudinal gradients in temperature and precipitation across the supercontinent, expressed in distinctive floral assemblages. The present study elucidates Late Permian and Permian–Triassic transitional vegetation dynamics and associated palaeoenvironmental conditions that were analysed from the palynological assemblages recovered from the Gungri Formation, Spiti Basin, Tethyan Himalaya. Two palynoassemblages were retrieved: Assemblage‐I (striate bisaccates + Densipollenites ) and Assemblage‐II (non‐striate bisaccates + Densipollenites ). The occurrence of minor Triassic taxa such as Lunatisporites spp., Lueckisporites virkkiae , Playfordiaspora spp., Densoisporites spp., and Lundbladispora brevicula within a predominantly Permian palynoflora, a pattern also documented in other Gondwanan basins together with the dominance of Densipollenites , suggests a younger latest Permian (Changhsingian) to Permian–Triassic transitional age for Assemblage‐II. Assemblage‐I reflects a lowland forest system characterized by glossopterid and cordaitalean canopy layers, an understorey of ferns and lycopsids, and the presence of conifers and peltasperms in upland or well‐drained habitats. Assemblage‐II records a marked increase in conifer abundance and diversity, coupled with a sharp decline in glossopterids and cordaites. This shift indicates a transition to warmer, subhumid to semi‐arid conditions, with conifers, peltasperms, and xeromorphic lycopsids dominating the landscape. Despite the predominance of xerophytic taxa, the persistence of hygrophilous elements in low frequencies suggests that localized subhumid refugia still existed. This floral turnover reflects a broader climatic and ecological transformation at the end of the Permian, from wet, peat‐forming ecosystems to arid‐adapted floras, a transition echoed across Gondwana and linked to the global environmental crisis culminating in the Permian–Triassic mass extinction.