Did Antarctic Supermountains Trigger the Cambrian Explosion?
- Ancient supermountains buried deep beneath Antarctic ice may have served as the ultimate catalyst for the Cambrian explosion of life, flooding ancient oceans with a rich bounty of...
- To piece together the vanished landscape, the research team gathered 1,712 zircon grains spanning 12 distinct sites across Antarctica.
- Continent-sized tectonic blocks crashed together during Gondwana's formation, producing giant mountain ranges, similar to how the Himalayas were formed.
Ancient supermountains buried deep beneath Antarctic ice may have served as the ultimate catalyst for the Cambrian explosion of life, flooding ancient oceans with a rich bounty of life-sustaining nutrients. Earth scientists Bei Chen and Ian Campbell of the Australian National University detailed their findings in the journal Earth and Planetary Science Letters, arguing that the dramatic evolutionary changes that occurred during the Cambrian should be matched by an environmental change of comparable importance.
Reconstructing Lost Peaks Through Zircon Dating
To piece together the vanished landscape, the research team gathered 1,712 zircon grains spanning 12 distinct sites across Antarctica. They applied uranium-lead dating techniques to pinpoint the exact crystallization age of each sample. The analysis revealed four clear peaks in particle ages. Most notably, the highest concentration—falling between 650 and 450 million years ago—directly corresponded with the assembly of the supercontinent Gondwana.
Tectonic Collisions and Himalayan-Scale Ranges
Continent-sized tectonic blocks crashed together during Gondwana’s formation, producing giant mountain ranges, similar to how the Himalayas were formed. Earlier studies demonstrated that central Australia and the Antarctic sector of Gondwana would have been moving rapidly enough toward each other to create that much force. Geological deposits analyzed by Chen and Campbell share key traits with those traced back to Himalayan-style mountains.
Unleashing Phosphorus, Iron, and Oxygen
The authors maintain that these extinct structures would have been much larger than those we see today, so it may be fitting to call these extinct features a “supermountain.” As these ranges eroded over the years, they would have shed vital nutrients—including phosphorus, iron, and carbonate molecules—down into the seas.
If rapid advances in evolution occur in response to favorable environmental change,
Bei Chen and Ian Campbell wrote in the paper, the dramatic evolutionary changes that occurred during the Cambrian should be matched by an environmental change of comparable importance.
This nutrient surge fed organisms at the very bottom of the food chain. Their subsequent photosynthesis sparked a huge leap in atmospheric oxygen, which was good news for more complex organisms. The study authors maintain this chronological alignment is no accident, pointing to the formation and erosion of the Gondwana Supermountains as a factor behind Earth’s most dramatic period of evolution.