Marine Isotope Stage 9

[1][2] It is the final period of the Lower Paleolithic and lasted from 337,000 to 300,000 years ago according to Lisiecki and Raymo's LR04 Benthic Stack.

The manner by which the data is obtained through core samples is mainly due to the sedimentation in the region which can be very indicative of an interglacial or glacial phases.

The data is retrieved from proxies, such as foraminifera and pollen that have diverse oxygen-18 to oxygen-16 ratios depending on the temperature in the ocean during said events.

[9] During this interglacial stage, Europe was occupied by Homo heidelbergensis, who had retreated from Britain during the preceding glacial period.

Within the area, thousands of hand axes and other artefacts have been found indicating their return after the increasing warmer temperatures.