260 million years ago, the seas lost oxygen, causing worldwide extinctions. Sediment records show it happened again 3 million years later. The discoveries may clarify the Permian period, which was obscured by the biggest global extinction catastrophe.

Five major extinctions killed most of Earth’s life. Our irresponsibility may have started a sixth. Paleontologists have questioned whether additional major extinctions should be considered.

End-Capitanian events have been a focus (also known as the end-Guadalupian). Some estimates say species loss was greater than when the asteroid destroyed the non-avian dinosaurs or two other major extinctions. A new analysis reveals that mixing together two events may be causing these figures to be contested.

A mass extinction that has been talked about for a long time happened 260 million years ago.

A team lead by Dr. Huyue Song of the China University of Geosciences studied uranium isotope ratios in marine sediments from the Guadalupian period 272 to 259 million years ago in the South China Sea. Marine bacteria convert uranium (VI) to (IV) but process U-235 and U-238 differently. A microbial die-off caused by a drop in ocean oxygen levels lowers saltwater uranium concentrations and shifts isotope ratios.

Song and co-authors found a 0.2-0.4 percent decrease in isotope ratio in rocks 260 million years old, indicating that the waters were severely oxygen-depleted twice throughout the Permian, 262 and 259 million years ago. Each of them would have triggered a huge marine extinction, which would have been reproduced on land, wiping off Titanophoneus, the “titanic killer.”

Like past mass extinctions, the dinosaur-killing one was caused by massive volcanic eruptions, according to the authors. When the ash washed out and carbon dioxide remained, these eruptions triggered short-term cooling and long-term warming.

“”The surface layer must absorb and supply dissolved oxygen to the deep ocean,” stated University of Cincinnati Professor Thomas Algeo. Warmer water is less dense. Increased density difference prevents overturn and dissolved oxygen from reaching deeper levels.”

Two huge eruptions produced a long-debated global extinction 260 million years ago.

“Global warming, ocean hypoxia, seawater acidification, and biodiversity decrease are similar to the Middle Permian biological crisis period,” Song added. Today’s changes are probably faster and less dramatic.

Tropical species disappeared at an unprecedented rate during the Capitanian extinction event. Nevertheless, evidence from temperate and polar latitudes is scarce, although Spitsbergen, the biggest island of the Norwegian archipelago Svalbard, supports the idea that this was a global occurrence.

The end-Permian, or Great Dying, was the biggest extinction event, therefore the Capitanian catastrophe may have been eclipsed. Confusion between events may have contributed.

Before now, volcanic eruptions were the main possibility, but a reason was unknown. Why three cataclysmic eruptions occurred in 10 million years is unclear.

    Leave a Reply