A team of researchers has identified up to six climate episodes that occurred about a million years ago at the Quibas site, located in the town of Abanilla (Murcia, Spain).

These findings, published in the journal Quaternary International, reveal a significant climate alternation for that period in Europe, marking the first time this pattern has been documented for the time span between 1.1 and 0.9 million years ago. These climate changes preceded the more intense glacial phases of the Middle Pleistocene, which occurred around 800,000 years ago.

The team led by Casto Laborda-López included researchers from the Complutense University of Madrid, the University of Murcia, the Autonomous University of Barcelona, and the Catalan Institute of Human Paleoecology and Social Evolution (IPHES-CERCA).

Archaeologists working at the site
Archaeologists working at the site. Credit: IPHES

To detect climate variations, the scientists analyzed the mineralogical composition of sediments at different levels of the site, which allowed them to identify layers deposited during arid glacial periods and others during wet interglacial periods.

The researchers were able to detect seven climate episodes during the interval between the MIS 33 and MIS 27 stages, a period that alternated four wet episodes with three arid ones. This is relevant because, until now, continuous records of these climate changes had mainly been documented in ocean floors, where sediments maintain a continuous record of the last 3 million years.

On land, the record tends to be discontinuous and incomplete, making discoveries like that at Quibas highly significant for better understanding climate history and its impact on Europe’s flora and fauna.

Entrance to the Quibas site, located at the foot of an abandoned quarry
Entrance to the Quibas site, located at the foot of an abandoned quarry. Credit: Ppinero / Wikimedia Commons

A million years ago, during the formation of the Quibas site, climate cycles were modulated in intervals of about 40,000 years due to variations in Earth’s axial tilt. The levels at the site have demonstrated significant changes in fauna related to these climate episodes.

For example, in the interglacial MIS 31, fossils were found of species associated with wooded and wet environments, such as the flying squirrel, shrew, and the legless lizard Ophisaurus manchenoi. However, in the glacial stage MIS 30, the fossils corresponded to reptiles like the Montpellier snake and the snub-nosed viper, indicating drier and shrubland environments.

The Quibas site, an ancient cave filled with sediments rich in vertebrate and invertebrate fossils, is unique in Europe due to its age and the diversity of species it contains. Since its discovery in 1994, it has provided remains of over 80 species, including large mammals like goats, bisons, horses, boars, and rhinoceroses, as well as saber-toothed tigers, Iberian lynxes, and macaques.

Iberian lynx femur found at the Quibas site during the 2021 excavation season
Iberian lynx femur found at the Quibas site during the 2021 excavation season. Credit: Ppinero / Wikimedia Commons

The wealth of fossils makes Quibas a key site for understanding climate and fauna evolution during the period between 1.1 and 0.9 million years ago.


Institut Català de Paleoecologia Humana i Evolució Social | Casto Laborda-López, David M. Martín-Perea, et al., Sedimentological evolution of the Quibas site: High-resolution glacial/interglacial dynamics in a terrestrial pre-Jaramillo to post-Jaramillo sequence from southern Iberian Peninsula. Quaternary International, doi.org/10.1016/j.quaint.2024.02.015

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