The Late Cretaceous is the latter division of the Cretaceous Period, spanning from approximately 100.5 million to 66 million years ago. It marks the final chapter of the Mesozoic Era and was a time of significant geological, climatic, and biological changes. Key features of this epoch include:

1. Geology and Plate Tectonics

Breakup of Pangaea: The continents were continuing to drift apart, forming more distinct landmasses.
Seas and Oceanic Expansion: High global sea levels led to the formation of shallow inland seas, such as the Western Interior Seaway in North America.
Mountain Formation: The Laramide Orogeny, responsible for creating the modern Rocky Mountains, began during this time.

2. Climate

The Late Cretaceous climate was generally warm and humid, with minimal polar ice caps.
High levels of atmospheric carbon dioxide contributed to a “greenhouse world.”
Tropical and subtropical climates were widespread, and forests extended into polar regions.

3. Flora

Angiosperms (flowering plants) became more dominant and diversified significantly.
Conifers, ferns, and cycads also remained important components of the landscape.

4. Fauna

Dinosaurs: The Late Cretaceous is famous for its diverse and iconic dinosaur fauna, including:
Tyrannosaurus rex, Triceratops, and other ceratopsians.
Duck-billed hadrosaurs like Edmontosaurus.
Carnivores like Velociraptor and Giganotosaurus.
Titanosaurs (massive sauropods) in South America and Africa.
Marine Life:
Marine reptiles like Mosasaurus and Elasmosaurus dominated the oceans.
Ammonites and rudists were common in marine environments.
Avian Dinosaurs and Birds: Early birds and feathered dinosaurs proliferated.
Mammals: Small, nocturnal mammals continued to evolve, paving the way for post-Cretaceous diversification.

5. Mass Extinction

The Late Cretaceous ended with the Cretaceous-Paleogene (K-Pg) extinction event around 66 million years ago.
A combination of a massive asteroid impact (Chicxulub Crater) and volcanic activity (Deccan Traps) likely caused widespread environmental upheaval, leading to the extinction of about 75% of species, including all non-avian dinosaurs.