The Last Permian Mass Extinction (LPME) was the largest extinction to date in Earth’s history and caused the loss of 80-90% of life on the planet. Despite a great deal of research, the exact cause of the sudden climate changes during this time is unknown.

An international team of scientists, including UConn Earth Sciences professor and department chair Tracy Frank and Professor Christopher Fielding, is collaborating to unravel the cause and events of the Last Permian Mass Extinction (LPME) by studying mercury deposits. It is found in Australian and South African sediments derived from Siberian volcanoes. Their research was recently published in the journal. Nature Communication.

Although the LPME occurred more than 250 million years ago, there are parallels with the major climate changes occurring today, Frank explains:

“This is important for understanding what may happen on earth in the future. The main cause of climate change is the release of large amounts of carbon dioxide into the atmosphere leading to rapid warming in times of extinction.”

In the case of the LPME, it is widely accepted that the rapid warming associated with the event was caused by massive volcanism occurring in a massive lava bed called the Siberian Traps Great Igneous State (STLIP), but direct evidence is still lacking, Frank said. were missing

Volcanoes leave useful clues in the geological record. The lava flow also released large quantities of gases such as CO2 and methane, as well as particulate matter and heavy metals that were released into the atmosphere and accumulated worldwide.

“However, it’s hard to directly relate something like this to an extinction event,” says Frank. “As geologists, we are looking for some kind of signature – what is a smoking gun – so we can pinpoint the cause.”

In this case, the researchers focused on mercury, one of the heavy metals associated with volcanic eruptions. The trick is to find areas where this record still exists.

Frank explains that there is a continuous record of Earth’s history found in sediments in the marine environment, acting almost like a tape recorder as the sediments are quickly buried and preserved. These sediments provide rich data on the extinction and how it occurred in the oceans. Such well-preserved records from this period are more difficult to find on land.

To explain this, Frank uses Connecticut as an example: a state rich in 400-500 million-year-old metamorphic rocks at or near the surface, covered with glacial deposits dating back to about 23,000 years ago.