Dinosaurs ruling the earth came after huge volcanic activity changing the environmental structure of the planet, according to a new study.
Researchers from the University of Birmingham uncovered the information by analysing sediment and fossil plant records from a lake in northern China’s Jiyuan Basin.
Chemical signatures point to volcanic activity. This correlates with environmental changes during the Late Triassic Carnian Pluvial Episode. The CPE saw an increase in temperature and plant growth.
The study data also reflected the CPE’s ‘mega monsoon’ climate, some 234 million to 232 million years ago.
Co-author Jason Hilton, Professor of Palaeobotany and Palaeoenvironments at the University of Birmingham’s School of Geography, Earth and Environmental Sciences, said: “Within the space of two million years the world’s animal and plant life underwent major changes including selective extinctions in the marine realm and diversification of plant and animal groups on land. These events coincide with a remarkable interval of intense rainfall known as the Carnian Pluvial Episode.
“Our research shows, in a detailed record from a lake in North China, that this period can actually be resolved into four distinct events, each one driven by discrete pulses of powerful volcanic activity associated with enormous releases of carbon dioxide into the atmosphere. These triggered an increase in global temperature and humidity.”
The international research team published their findings in Proceedings of the National Academy of Sciences (PNAS) – revealing four distinct episodes of volcanic activity during this time period.
It also suggests the most likely source being major volcanic eruptions from the Wrangellia Large Igneous Province, the remnants of which are preserved in western North America.
Researchers found that each phase of volcanic eruption coincided with major climatic changes to more humid conditions, as well the lake’s deepening with a corresponding decrease in oxygen and animal life.
Dr Emma Dunne, a Palaeobiologist also at the University of Birmingham, who was not involved in the study, commented: “This relatively long period of volcanic activity and environmental change would have had considerable consequences for animals on land.
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“At this time, the dinosaurs had just begun to diversify, and it’s likely that without this event, they would never have reached their ecological dominance we see over the next 150 million years.”
Professor Hilton added: “In addition to dinosaurs, this remarkable period in Earth history was also important for the rise of modern conifer groups and had a major impact on the evolution of terrestrial ecosystems and animal and plant life – including ferns, crocodiles, turtles, insects and the first mammals.”