Carnian Pluvial Episode timeline

A prolonged period of intense rainfall, known as the Carnian Pluvial Episode, occurred between 234 and 232 million years ago, according to multiple studies. This climatic event, triggered by volcanic eruptions from the Wrangellia province, significantly altered global vegetation and led to the extinction of large herbivores such as dicynodonts and rhynchosaurs.

Dinosaurs rise after the event

Dinosaurs, which had appeared approximately 245 million years ago, took advantage of the ecological changes to rise to prominence between 232 and 230 million years ago. The extinction of other herbivores and the transformation of the environment created new ecological niches that dinosaurs were able to fill.

Discovery and confirmation of the event

The Carnian Pluvial Episode was first described by geologists Simms and Ruffell in 1989, who identified signs of a humid climate in sedimentary rocks from that period. Researchers later confirmed the event's significance through studies, including one published in the journal PNAS, which analyzed a lake core from northern China and identified four distinct rainy periods linked to volcanic activity.

Volcanic impact on marine life

A study published in Science Advances by researcher Jacopo Dal Corso and sixteen other scientists, including Mike Benton from the University of Bristol, linked the Wrangellia eruptions to a major extinction event around 233 million years ago, during which approximately 33 percent of marine genera disappeared. The volcanic activity also left a distinct geochemical signature, a marked negative peak in the carbon isotope ratio (δ13C), identified in Carnian rocks.

Fossil evidence of dinosaur dominance

Fossil evidence supports the theory that the Carnian Pluvial Episode facilitated the rise of dinosaurs. Researchers Bernardi, Gianolla, Petti, Mietto, and Benton noted an increase in dinosaur footprints in the Italian Dolomites and a rise in dinosaur fossils found in Argentina and Brazil during the period following the pluvial episode. This suggests that the ecological changes caused by the volcanic eruptions and subsequent rainfall created new opportunities for dinosaurs to thrive, leading to their eventual dominance in terrestrial ecosystems.