When did the Quaternary Period begin?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Quaternary paleogeography — Quaternary Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the Quaternary Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

The Quaternary Period began 2,588,000 years ago.12

While earlier scientific conventions once placed the start of the Quaternary at approximately 1.8 million years ago, the International Union of Geological Sciences (IUGS) officially ratified the current date in 2009. This boundary is defined by the base of the Gelasian Stage, which is marked in the rock record at Monte San Nicola near Gela, Sicily. This point in time coincides with significant geological evidence of widespread ice sheet expansion across the northern continents and the onset of a period characterized by dramatic climatic and oceanographic changes.132