An asteroid, not volcanism, may have killed the dinosaurs, according to new computer study.

Researchers employ innovative methods to determine what led to the catastrophic extinction.

Whether a large volcanic eruption or an asteroid hit terminated the reign of the dinosaurs 66 million years ago has been the subject of intense scientific discussion for many years. The Cretaceous Period came to an abrupt end at that point when all nonbird dinosaurs, comprising roughly three-quarters of all life on Earth, became extinct.

Researchers have now come up with a new strategy to find the real dinosaur killer: let computers have a go.

The team reveals in the Sept. 29 Science that the outcome of their computational work points to the extinction catastrophe being primarily caused by the huge bursts of gas created by the Deccan Traps eruptions. During those eruptions, which lasted for around a million years, vast quantities of gas-filled lava were thrown across what is now western India.

The objective was to have as little human involvement or bias in the process as possible, according to Dartmouth computational geologist Alexander Cox, rather than approaching it from the perspective of “let’s blame the volcanoes and explain why” or “let’s blame asteroids and explain why.”

The plan was to use the evidence found at the crime site to work backward. The geologic information found in cores taken from deep ocean strata points to lethal releases of gases into the atmosphere, particularly sulfur dioxide, which causes acidification of the oceans, and carbon dioxide, which warms the earth.

However, according to Cox, these gases might have come from either the Deccan Traps eruptions or the asteroid strike, which burned up rocks on the planet’s surface.

A statistical model known as a Markov chain Monte Carlo technique was employed by Cox and Dartmouth geologist C. Brenhin Keller to separate the relative contributions of each possible offender. This method methodically evaluates the likelihood of various gas emission scenarios from various sources, convergent toward potential solutions as simulation results get closer and closer to geologic data.

The researchers’ method was especially effective since they used 128 distinct processors to execute scenarios concurrently, according to Cox. At the conclusion of each model run, “all the processors then compared how they were doing, like classmates comparing answers.” Due to the simultaneous processing, computations that otherwise would have taken a year only took a few days.

Data from three cores that were excavated into deep-sea sediments, each covering 67 million to 65 million years ago, were used by Cox and Keller to make their discoveries. Foraminifera, marine microorganisms with carbonate shells that carry various isotopes of carbon and oxygen, are found in those sediments. Because the chemical composition of the shells records the ocean chemistry at the time of their creation, they can be used as a proxy to estimate previous global temperatures, the abundance of marine life, and the amount of carbon that was circulating between the atmosphere, ocean, and land.

The results of the computer models showed that the volcanism alone released enough gas into the atmosphere to explain the changes in temperature and carbon cycling.

However, many experts do not believe that these discoveries offer the conclusive solution to this difficult subject. According to Sierra Petersen, a geochemist at the University of Michigan in Ann Arbor, “it’s an elegant way to address this problem.” This type of modeling “gives the freedom to identify the consensus answer, taking into account different proxy data. Like any model, though, the outcome depends on the input.

Foraminifera shells are not the best indicator of prehistoric temperatures, according to Petersen. In addition to temperature, seawater composition can also affect the oxygen isotope ratios in foraminifera shells. distinct temperature proxies would probably result in distinct gas release patterns being replicated in simulations.

She goes on to argue that it would be a bit of a stretch to claim that this study disproves the impact theory as the cause of the mass extinction. What they demonstrate, in my opinion, is that the impact was probably not brought on by a significant [gas] leak. She claims that the asteroid could still have had other fatal effects on the ecosystem of the planet.

Indeed, according to Clay Tabor, a paleoclimatologist at the University of Connecticut in Storrs, “the Chicxulub impact led to many devastating effects beyond the carbon dioxide and sulfur dioxide emissions explored in this study.”