Dartmouth College researchers have adopted a novel approach to resolve the debate about whether a massive asteroid impact or volcanic activity led to the extinction of dinosaurs 66 million years ago. They removed human bias by using a computer model to analyze the Cretaceous–Paleogene (K–Pg) extinction event.
The team utilized nearly 130 processors to reverse-engineer the fossil record, seeking to identify the conditions and events leading to this extinction. Their method, which refrains from relying on predetermined hypotheses, involved running a carbon-cycle model in reverse, guided by minimal prior information. The model processed over 300,000 scenarios involving carbon dioxide and sulfur dioxide emissions and biological productivity.
Geochemical and organic evidence in the fossil record indicates extreme environmental changes during the K–Pg extinction. This period is marked by shifts from cold to hot conditions, caused by atmospheric instability due to pollutants like sulfur and carbon dioxide. While it’s clear that these conditions led to the extinction, the debate has been whether an asteroid impact or volcanic activity was the primary cause.
Historically, theories pointed to volcanic eruptions, particularly from India’s Deccan Traps. However, the discovery of the Chicxulub crater in Mexico, formed by a large asteroid, shifted the focus. Recent evidence suggests a combination of both: an asteroid impact on a planet already affected by massive volcanic eruptions.
The computer model suggested that emissions from the Deccan Traps alone might have been enough to cause the extinction. These volcanoes released significant amounts of carbon dioxide and sulfur dioxide over nearly a million years. However, the model also noted a significant drop in organic carbon in the ocean around the time of the Chicxulub impact, indicating its role in the extinction but without a spike in gas emissions.
The researchers highlighted the alarming rate of current carbon dioxide emissions, which significantly surpasses that from the Deccan Traps. They emphasize the potential of their method in analyzing other geological events, offering a new, bias-resistant approach to understanding earth systems and their historical impacts.
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