A new study on what might have started the Cambrian Explosion

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Several studies have suggested that the most credible factor that helped lead to the Cambrian Explosion, the massive and rapid expansion of different lifeforms about 500 million years ago, was a significant rise in oxygen levels at this time. A new study has now suggested that this rise in oxygen may have resulted from large changes in plate tectonics. The study found that, during the formation of Gondwana, a massive increase in continental arc volcanism, which consists of chains of volcanos that can reach thousands of miles in length that are formed from the collisions of continental and oceanic plates, occurred. This led to higher amounts of "de-gassing" of CO2 from the ancient, subducted, sedimentary rocks. This then led to an increase in atmospheric CO2, which warmed the planet and amplified the weathering of continental rocks, which supplied nutrient phosphorous to the ocean that helped to drive photosynthesis and oxygen production. This study found that this increase in oxygen production was over the limit that would have been needed to support the large influx of new lifeforms during the explosion, suggesting that this could be the cause of this extremely significant event. Here is a link to the paper describing this study.

Paper (open access!): https://www.nature.com/articles/s41467-019-10286-x