Ecological changes led to the dominance of the dinosaurs

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A new study shows that the increase in dinosaurs was accompanied by environmental changes caused by major volcanic eruptions over 230 million years ago.

Ecological changes following intense volcanic activity 230 million years ago paved the way for dinosaur dominance. Image source: University of Birmingham.

The Late Triassic Carnic Pluvial Episode (CPE) showed an increase in global humidity and temperature. This had a significant influence on the development of the flora and fauna and at the same time as the development of modern conifers.

The sediment and fossil finds collected from a lake in northern China’s Jiyuan Basin were examined by scientists. This corresponded to pulses of volcanic activity with considerable environmental fluctuations, such as the “megamonsoon” climate of the CPE about 234 million to 232 million years ago.

The international research group, which also included experts from the University of Birmingham, recently reported on the study results in Proceedings of the National Academy of Sciences (PNAS).

The study reveals four different episodes of volcanic activity during this period, with the most likely source being significant volcanic eruptions from the Wrangellia Large Igneous Province, the remains of which are held in western North America.

Within two million years, the world’s animal and plant life has changed dramatically, including selective marine extinction and diversification of plant and animal groups on land. These events coincide with a notable interval of intense rainfall known as the Carnic Pluvial Episode.

Jason Hilton, study co-author and Professor of Palaeobotany and Palaeoenvironments, School of Geography, Earth and Environmental Sciences, University of Birmingham

Our research shows, in a detailed recording from a lake in northern China, that this period can actually be broken down into four different events, each is powered by discrete pulses of strong volcanic activity that are associated with enormous releases of carbon dioxide into the atmosphere. These triggered an increase in global temperature and humidity“Added Hilton.

The scientists discovered that each phase of the volcanic eruption coincided with major climatic changes leading to more humid conditions, an enormous disruption of the global carbon cycle and deepening of the lake with a corresponding decrease in oxygen and wildlife.

Geological events that occurred in a similar timeframe in East Greenland, Central Europe, North America, Morocco, and Argentina, among others, indicate that increased rainfall led to extensive expansion of catchment areas that converged into swamps or lakes rather than oceans or rivers.

Our results show that large volcanic eruptions can occur multiple times, discrete pulses – demonstrate their powerful ability to change the global carbon cycle, cause climatic and hydrological disturbances and drive evolutionary processes.

Dr. Sarah Greene, Degree Co-Author and Senior Lecturer, School of Geography, Earth and Environmental Sciences, University of Birmingham

According to Dr. Emma Dunne, a paleobiologist also from the University of Birmingham who was not involved in the study, “This relatively long period of volcanic activity and environmental changes would have had significant consequences for the animals on land. At this point, the dinosaurs had only just begun to diversify, and itThat is probably without this event, they would never have achieved the ecological dominance that we will see in the next 150 million years. “

Besides dinosaurs, This remarkable period in Earth’s history was also important for the rise of modern conifer groups and had a major impact on the development of terrestrial ecosystems as well as the flora and fauna – including ferns, Crocodiles, Turtles, insects, and the first mammals.

Jason Hilton, study co-author and Professor of Palaeobotany and Palaeoenvironments, School of Geography, Earth and Environmental Sciences, University of Birmingham

The researchers examined terrestrial sediments from borehole ZJ-1 in the Jiyuan Basin in northern China. Using high-resolution chemostratigraphy, uranium-lead-zircon dating, palynological and sedimentological data, they compared the terrestrial conditions in the region with simultaneous large-scale volcanic activity in North America.

Journal reference:

Lu, J., et al. (2021) Volcanic changes in the lacustrine ecosystem during the Carnic pluvial episode (late Triassic). Proceedings of the National Academy of Sciences. doi.org/10.1073/pnas.2109895118.

Source: https://www.birmingham.ac.uk/index.aspx


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