Dinosaurs Thrived Until the Asteroid Struck
▼ Summary
– The dinosaur extinction was caused by an asteroid impact, though the details have been debated due to conflicting evidence about its role versus volcanic activity.
– A new study found that fossils from just before the impact show species richness was not a major issue in the impact area, challenging earlier diversity concerns.
– Most knowledge about the dinosaurs’ final days comes from the Hell Creek Formation in Wyoming, which provides fossils from the last few hundred thousand years before extinction.
– It is unclear if the species diversity at Hell Creek reflects global conditions, as there are few comparable fossil records from other regions.
– The lack of global fossil data makes it hard to determine if dinosaurs were already in decline worldwide before the asteroid impact.
The extinction of the dinosaurs is definitively linked to the catastrophic asteroid impact that marked the end of the Cretaceous period. While the discovery of the impact crater settled the primary cause, the finer details of their demise have remained a subject of scientific discussion. Compelling evidence suggests the impact alone possessed the destructive power to cause their extinction. However, this event occurred during a period of significant volcanic activity, which has been tied to earlier mass extinctions. Furthermore, fossil records from the time just before the impact have hinted that dinosaur-dominated ecosystems were experiencing a decline in diversity, potentially making them more vulnerable to a major collapse.
A recent study has shed new light on this mystery by analyzing fossils known to originate from the final few hundred thousand years preceding the impact. The findings suggest that species richness was likely not a significant issue for the dinosaurs living in the area affected by the impact, at least in that specific region.
Our understanding of the final chapter for non-avian dinosaurs relies heavily on the fossil-rich Hell Creek Formation, located in what is now Wyoming. These deposits not only date to within a narrow window of time before the asteroid struck but may also contain evidence from the immediate aftermath. This formation provides a detailed snapshot of the northern Great Plains ecosystem, yet it leaves a major question unanswered. It remains unclear whether the diversity seen at Hell Creek was representative of the global dinosaur population or if there were substantial regional variations in ecosystems.
This distinction is critical because it addresses the core of the debate regarding the dinosaurs’ condition right before the impact. If the community structure observed at Hell Creek was the global standard, it would support the argument that dinosaurs had already lost the ecological resilience needed to survive a disaster of such magnitude.
To properly contextualize the Hell Creek fossils, scientists require comparable data from other parts of the world. Unfortunately, all other known fossil collections from this precise era are scarce. Most available assemblages are from much earlier in the Cretaceous period, making it exceptionally difficult to draw firm conclusions about worldwide dinosaur diversity in their final days.
(Source: Ars Technica)
