For X-ray fluorescence analysis at the University of Brussels, slices of bone cut in epoxy resin are placed on glass balls (Source: Author). Springer Nature Courtesy photo
BEIJING, Feb. 24 (Xinhua) -- The era of dinosaurs, the once dominant dinosaur on Earth, went extinct due to an asteroid impact event 66 million years ago. Which of the most remarkable events in the history of earth's evolution occurred in spring, summer, autumn and winter?
A recent evolutionary research paper published in the internationally renowned academic journal Nature believes that the Hicksulub asteroid impact event that ended the dinosaur era (Mesozoic) occurred in the spring of the northern hemisphere. The findings help explain subsequent extinction patterns and improve understanding of this critical moment in Earth's history.
Artistic reproduction of the asteroid impact event (Source: Joschua Knüppe). Springer Nature Courtesy photo
About 66 million years ago, a giant asteroid crashed into what is now Mexico's Yucatan Peninsula, causing an extinction that killed 76 percent of Earth's species, including non-avian dinosaurs, pterosaurs and ammonites, according to the paper. Previously, research on the timing of this event had focused on the millennium scale, so the season in which the impact occurred was unknown.
To address this problem, the paper's corresponding author, Melanie During of uppsala University in Sweden, and collaborators studied the remains of filter-feeding sturgeon fish (Sturgeon and Spoon Sturgeon) that died en masse during impact events, providing a record of seasonal changes. They combined carbon isotope data for analysis and showed that the fish died in the spring in the northern hemisphere.
The corresponding author of the paper excavates a spoon sturgeon in sediment (Credit: Jackson Leibach). Springer Nature Courtesy photo
The fish fossils, found in late Cretaceous sediments in North Dakota, U.S.A., had impact debris in their gills but did not penetrate deep into the digestive system, suggesting that they died almost immediately in a sudden surge in the upper reaches of the river caused by a lake earthquake (where land water shook under impact) caused by an impact, the authors said. This catastrophe occurred in the spring, which happens to be a sensitive phase for many northern hemisphere species to reproduce and raise offspring in the spring. The authors also mention that the southern hemisphere ecosystem was in the midst of a period of autumn stagnation, and later recovered nearly twice as fast as the northern hemisphere. (End)
Source: China News Network