Marine Isotope Stage 9

Marine Isotope Stage 9

Marine Isotope Stage 9, also called MIS 9, was a warm time on Earth a very long time ago. It was an interglacial, meaning the ice age was resting and the world was warmer. This time was important because it was the last part of what we call the Lower Paleolithic.

Scientists have different ideas about when exactly MIS 9 happened. Some say it lasted from 337,000 to 300,000 years ago, while others think it was from 328,000 to 301,000 years ago.

In places like Great Britain, this warm time is called the Purfleet Interglacial. Scientists also study how MIS 9 was split into smaller parts. Some think there were two warm times and one cooler time, while others found three warm times and two cooler times during this stage.

MIS Drivers

Marine Isotope Stages are times when the Earth goes through cold glacial periods and warm interglacial periods. These changes are mainly driven by the Milankovitch Cycles, which affect how much sunlight the Earth receives. Scientists study deep sea core samples to learn about these past climate changes.

MIS are studied using oxygen isotope analysis from core samples. This helps us understand past climate changes, including glacial and interglacial periods. The data comes from things like foraminifera and pollen, which have different amounts of oxygen-18 and oxygen-16 depending on the ocean temperature at the time. High isotope ratios show colder glacial times, while low ratios show warmer interglacial times.

Interglacial Impacts on Living Organisms

European culture impacts

During this warm time, called an interglacial stage, people known as Homo heidelbergensis returned to Europe. They came back when the climate became warmer and sea levels rose about 330,000 years ago. We know they were there because we found many tools, like hand axes, near old river paths in Europe. In southern England, summers were about the same or a bit warmer than today, and winters were slightly cooler. This time also saw the start of a new way of making stone tools called the Clactonian culture.