What major geographical change occurred during the Cretaceous Period?

During the Cretaceous Period, one of the most significant geological changes was the creation of the North Atlantic Ocean. This period, which lasted from approximately 145 to 66 million years ago, was marked by substantial tectonic activity. The supercontinent Pangaea began to rift and break apart into smaller continents, which led to the opening of ocean basins.

As the North American and Eurasian tectonic plates moved apart, the Atlantic Ocean began to expand. This process involved the movement of continental and oceanic crusts and contributed to the significant geological features we observe today. The creation of the North Atlantic Ocean facilitated changes in ocean currents, sea levels, and climate, which in turn affected the distribution of flora and fauna during this time.

The other options refer to geological events that either predate or are not directly representative of the Cretaceous Period. The Appalachian Mountains were formed much earlier in Earth's history, primarily during the Paleozoic Era. The Rocky Mountains also formed predominantly during the Laramide Orogeny, which largely took place at the end of the Cretaceous and into the following epoch. The Ice Ages occurred much later, during the Quaternary Period, following the Cretaceous Period. Hence, the creation