A new study published in the journal Earth and Planetary Science Letters suggests that the formation of vast mountain ranges in Antarctica during the assembly of the supercontinent Gondwana, around 650 to 450 million years ago, might have played a role in creating conditions that helped complex animal life evolve. The researchers argue that these mountains would have eroded and deposited large amounts of sediment into surrounding oceans, providing essential nutrients that could have supported the development of more complex life forms. The study connects this idea to events like the Cambrian explosion, a period around 540 to 520 million years ago when a wide variety of complex animals appeared in the fossil record. This event is linked to a rise in atmospheric oxygen, which is thought to have begun in the Neoproterozoic era, between 1 billion and 541 million years ago. However, the exact timing and scale of this oxygen increase are still uncertain. Oxygen is produced by photosynthetic organisms, but for it to accumulate in the atmosphere, the organic carbon created by these organisms must not react with the oxygen. A major increase in atmospheric oxygen, known as the second major oxidation event, is believed to have occurred when a large amount of organic carbon was buried in sediments. The study suggests that the mountain ranges formed during Gondwana’s assembly may have helped with this carbon burial, thereby promoting the rise of complex life. To support this hypothesis, researchers analyzed zircons—tiny mineral grains—found in ocean sediments from Antarctica. By studying 1,712 newly collected zircons and thousands of previously studied ones, they identified a significant peak in zircon dating between 650 and 450 million years ago, which corresponds to the time when Gondwana was forming. These zircons showed signs of high-pressure conditions, indicating intense mountain-building activity similar to the formation of the Himalayas. The researchers believe that as these mountains rose, they would have been heavily eroded, releasing nutrients like phosphorus and iron into the oceans. These nutrients would have supported the growth of photosynthetic organisms, such as algae and cyanobacteria, leading to more oxygen production. This, in turn, could have helped create the conditions necessary for the rise of complex animals. While the study does not confirm a direct link between these mountains and the Cambrian explosion, it suggests that the environmental changes caused by the mountain ranges could have contributed to a significant diversification of life.