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Where is the rock layer that marks the beginning of the Quaternary Period?

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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 rock layer that marks the beginning of the Quaternary Period is defined by a Global Boundary Stratotype Section and Point (GSSP) located at Monte San Nicola, near the town of Gela in Sicily, Italy.123

This specific site serves as the type section for the Gelasian Stage, which is the lowermost stage of the Pleistocene Epoch. The boundary is situated within marly shales on the southern slope of the mountain, positioned approximately one meter above the Gauss/Matuyama paleomagnetic boundary.13

In 2009, the International Union of Geological Sciences (IUGS) officially ratified this location as the marker for the base of the Quaternary, dating it to 2,588,000 years ago. This point in the rock record coincides with evidence of widespread ice sheet expansion and significant climatic and oceanographic shifts.13