Deep-Ocean Oxygen Came and Went for About 100 Million Years After Animals Spread, Thallium Record Shows
Nature World News | 09.11.2026 12:24
For decades, a common story about early animal life held that the deep ocean filled with oxygen around 540 million years ago, setting the stage for an explosion of complex creatures. A study of ancient seafloor mud from Canada's Yukon suggests that switch never flipped cleanly.
