Tortonian

The Tortonian is a time period in the geologic time scale that was part of the late Miocene. It lasted from about 11.6 million years ago to 7.2 million years ago. This stage came after the Serravallian and was followed by the Messinian.

During the Tortonian, many important changes were happening on Earth. It overlapped with several regional stages and land mammal ages in different parts of the world. This includes the Pannonian Stage in Central Europe, as well as various land mammal ages in Europe, North America, and South America. The Tortonian helps scientists understand how life and Earth’s surface were changing during this part of history.

Definition

The Tortonian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian city of Tortona in the Piedmont region.

The Tortonian is defined by certain tiny fossils found in rock layers. It marks a specific time period in Earth's history, helping scientists understand how the planet has changed over millions of years.

Geologic history

Geologists discovered two huge volcanic eruptions linked to the Yellowstone hotspot, one of which was the largest eruption in that area. This eruption happened about 8.72 million years ago.

Around 10 million years ago, the flow of deep water from the North Atlantic into the Indian Ocean became much stronger.