Ben Linzmeier holds a fossilized clam shell found while trekking through the Lopez de Bertodano Formation, a well-preserved, fossil-rich area on the west side of Seymour Island in Antarctica. Credit: Northwestern University
Phys.org has an interesting story about the extinction of the dinosaurs. A new study, led by researchers from Northwestern University, shows that the chemistry of fossilized clam and snail shells changed greatly in the years leading up to the K-Pg mass extinction event. This change is likely due to a large influx of carbon into the oceans which was caused by the long-term volcanic eruptions that formed the Deccan Traps. The Deccan Traps are a 200,000 square mile volcanic province located in modern day India. Find all the detail in a paper published in the journal Geology.
New evidence gleaned from Antarctic seashells confirms that Earth was already unstable before the asteroid impact that wiped out the dinosaurs.
The study, led by researchers at Northwestern University, is the first to measure the calcium isotope composition of fossilized clam and snail shells, which date back to the Cretaceous-Paleogene mass extinction event. The researchers found that—in the run-up to the extinction event—the shells' chemistry shifted in response to a surge of carbon in the oceans.
This carbon influx was likely due to long-term eruptions from the Deccan Traps, a 200,000-square-mile volcanic province located in modern India. During the years leading up to the asteroid impact, the Deccan Traps spewed massive amounts of carbon dioxide (CO2) into the atmosphere. The concentration of CO2 acidified the oceans, directly affecting the organisms living there.
"Our data suggest that the environment was changing before the asteroid impact," said Benjamin Linzmeier, the study's first author. "Those changes appear to correlate with the eruption of the Deccan Traps."
"The Earth was clearly under stress before the major mass extinction event," said Andrew D. Jacobson, a senior author of the paper. "The asteroid impact coincides with pre-existing carbon cycle instability. But that doesn't mean we have answers to what actually caused the extinction."
