Europe Middle Pleistocene glacial cycles

Marine Isotope Stage 9 (MIS 9) was an

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...

(warm)

Marine Isotope Stage Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from Oxygen isotope ratio cycle, oxygen isotope data derived from deep sea core ...

. It was the last period of the

Lower Paleolithic The Lower Paleolithic (or Lower Palaeolithic) is the earliest subdivision of the Paleolithic or Old Stone Age. It spans the time from around 3.3 million years ago when the first evidence for stone tool production and use by hominins appears ...

. Estimates of its dating vary. It lasted from 337,000 to 300,000 years ago according to Lisiecki and Raymo's 2005 LR04 Benthic Stack, whereas Rawlinson et al dated it in 2022 to between 328,000 and 301,000 years ago. It corresponds to the Purfleet Interglacial in Britain, and the Holstein Interglacial in continental Europe. Views on its division into sub-stages also vary. A 2013 study divided it into two warm

interstadial Stadials and interstadials are phases dividing the Quaternary period, or the last 2.6 million years. Stadials are periods of colder climate, and interstadials are periods of warmer climate. Each Quaternary climate phase has been assigned with a ...

s (9a and 9c) and one cooler stadial (9b), whereas a 2025 study had three warm sub-stages (9a, 9c and 9e) and two which were cooler (9b and 9d).

MIS Drivers

Marine Isotope Stages are

glacial A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

and interglacial periods throughout time. One of the processes that drive this major change are the

Milankovitch Cycles Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The term was coined and named after the Serbian geophysicist and astronomer Milutin Milanković. In the 1920s, he pr ...

, which control the

insolation Solar irradiance is the power per unit area ( surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre ...

received from the Sun. The data is retrieved from deep sea core samples. 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.

Marine Oxygen Isotopes

MIS are obtained through

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...

analysis within the core samples to understand

paleoclimate Paleoclimatology ( British spelling, palaeoclimatology) is the scientific study of climates predating the invention of meteorological instruments, when no direct measurement data were available. As instrumental records only span a tiny part of ...

changes. This includes glacial and interglacial periods. The data is retrieved from proxies, such as

foraminifera Foraminifera ( ; Latin for "hole bearers"; informally called "forams") are unicellular organism, single-celled organisms, members of a phylum or class (biology), class of Rhizarian protists characterized by streaming granular Ectoplasm (cell bio ...

and

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

that have diverse oxygen-18 to

oxygen-16 Oxygen-16 (symbol: 16O or ) is a nuclide. It is a stable isotope of oxygen, with 8 neutrons and 8 protons in its nucleus, and when not ionized, 8 electrons orbiting the nucleus. Oxygen-16 has a mass of . It is the most abundant isotope of oxyg ...

ratios depending on the temperature in the ocean during said events. When the isotopic analysis results in high isotopic ratio values, it is representative of colder glacial environments, while isotopic values with low ratios are indicative of warmer temperatures.

Interglacial Impacts on Living Organisms

European culture impacts

During this interglacial stage, Europe was occupied by ''

Homo heidelbergensis ''Homo heidelbergensis'' is a species of archaic human from the Middle Pleistocene of Europe and Africa, as well as potentially Asia depending on the taxonomic convention used. The species-level classification of ''Homo'' during the Middle Pleis ...

'', who had retreated from Britain during the preceding glacial period. Populations returned as the climate warmed and sea levels rose around 330,000 years ago. The evidence of their return is found along terraces of the Thames and former Solent rivers of Europe. Within the area, thousands of hand axes and other artefacts have been found indicating their return after the increasing warmer temperatures. In Southern England, the summers were similar to or slightly warmer than today, and the winters slightly cooler. The period saw a transition to Clactonian culture for manufacture of stone tools.

References

{{reflist Marine isotope stages Interglacials