Sprecher
Beschreibung
The Carnian stage is a milestone in the Mesozoic evolution of plants with the radiation of key conifer and fern groups, bennettites and Cheirolepidaceae, all temporally linked to the Carnian Pluvial Episode (CPE) in the Late Triassic. The CPE was a major hyperthermal event marked by climate and carbon cycle perturbations. Although widely studied, especially in the Western Tethys, patterns of climate and biotic change remain poorly understood. Here we demonstrate climatic and environmental perturbations during the Carnian based on the palynological study of five borehole successions from the Transdanubian Range. The early Carnian climate was characterized by a strong monsoonal regime with a mixture of hygrophyte and xerophyte floral elements, and the proliferation of the Enzonalasporites group. We found evidence for an early Carnian carbon cycle perturbation with a negative carbon isotope excursion (NCIE) and a short-lived proliferation of hygrophyte flora prior to the CPE but with smaller marine biotic impact. Floral turnover peaked in the late Julian with the expansion of hygrophyte lowland vegetation parallel with the demise of marine biota and primary producers. Floral response and carbon cycle trends show a decoupling from the early Tuvalian (early late Carnian) when palynological assemblages indicate gradual aridification despite episodes of carbon cycle instability and elevated clastic influx. This new view on terrestrial and marine biotic events in the Western Tethys points to an overall longer interval of environmental instability in the Carnian that climaxed during the early Julian NCIE, and in the late Julian during the peak CPE phase.