Asteroid Impact Not Solely Responsible for Dinosaur Extinction, Fossil Study Suggests

A groundbreaking study is challenging the long-held belief that dinosaurs were already experiencing a population decline before the catastrophic asteroid impact 66 million years ago. The research suggests that the scarcity of fossils from that period may have created a misleading impression of a dwindling dinosaur population.

Fossil Record Imperfections Skew dinosaur Population Data

Christopher Dean from UCL Earth Sciences and his team conducted the research, which questions the conventional view of a pre-impact dinosaur decline. The study,published in *Current Biology*,posits that a perceived decrease in dinosaur numbers might stem from an incomplete fossil record rather than actual extinction events preceding the asteroid’s arrival.

Did You Know? The Cretaceous-Paleogene extinction event, caused by the asteroid impact, wiped out approximately 76% of plant and animal life on Earth ^[1].

The team analyzed geological factors influencing fossil preservation, concluding that dinosaurs might have thrived until the cataclysmic event. This raises the intriguing possibility that dinosaurs could still roam the Earth today had the asteroid not struck.

“There are fewer rock formations from the end of the Cretaceous period that are accessible for investigation,” explains Christopher Dean. “This limited access makes it harder to find fossils from that period, resulting in an incomplete record of dinosaurs leading up to the asteroid impact.”

Analyzing Cretaceous Period Fossils

the research focused on fossil records from the last 18 million years of the Cretaceous period (84 to 66 million years ago). scientists scrutinized over 8,000 fossils from four dinosaur groups, with particular attention to families like Ankylosauridae and Ceratopsidae. Ceratopsians, including horned dinosaurs like Triceratops, were found to be the most common, indicating rapid development before the asteroid impact.

While the study identified a decrease in dinosaur fossils nine million years before the impact, this decline was attributed to reduced fossil discoveries rather than a genuine drop in the dinosaur population. The limited exposure of rock layers containing fossil evidence reduces the likelihood of finding fossils, suggesting that the dinosaur population in those areas remained relatively stable.

Pro Tip: Paleontologists use various dating methods, including radiometric dating, to determine the age of fossils and the rock layers in which they are found ^[2].

Residential Modeling and Geological Transformation

The study employed residential modeling, an ecological technique used to estimate the probability of finding dinosaur fossils in North America. Researchers assumed that the area inhabited by dinosaurs remained constant during the studied period. Geological transformations, such as tectonic activity, mountain erosion, and receding inland seas, disrupt fossilization and decrease the availability of fossil-bearing rocks.

Dr. Alesandro Chiarenza, a research author, stated, “When interpreted correctly, fossil records suggest that a decrease in dinosaur diversity is more likely caused by geological processes that limit fossil preservation, rather than an actual biological decrease.” he added that the loss of inland seas and changes in river systems could explain the lower fossil availability during this period.

Dinosaurs’ Potential Survival

The research suggests that dinosaurs might have survived if not for the asteroid impact. Dr. Alessandro chiarenza emphasized that dinosaurs were likely not destined to disappear at the end of the Mesozoic period. Without the asteroid, dinosaurs might have coexisted with mammals, lizards, and the ancestors of modern-day birds.

Fastest Dinosaurs

While the asteroid impact is a major factor in the extinction of the dinosaurs, it is engaging to note that the small theropod Compsognathus was found to be the fastest dinosaur in a small study [[3]].