2023-09-15 20:15:50
Around 1,800,000 years ago, Humanity left Africa and began to populate the lands of Asia and Europe. They were crude creatures, who used rudimentary stone tools, did not know fire and fed on the wild fruits they found and the carrion left by other predators more skilled than them. Its expansion was motivated by changes in the environment and its advance towards western Europe was very slow. In the Iberian Peninsula, the oldest remains and tools have been found in two sites, one is in the north, in the Sima del Elefante of the Sierra de Atapuerca, and the other in the south, in the Barranco del León site, in the province of Granada. These sites reveal a hominid presence from 1.4 million years ago.
The human population of those times had to overcome enormous environmental challenges. They survived the changes due to glaciations, which were repeated one after another, separated by warmer periods. Paleoenvironmental reconstructions have indicated that interglacial periods were warm and wet and glacial periods were mild, supporting the view that once established, hominid populations persisted continuously.
However, 1.12 million years ago, a climatological phenomenon occurred that disrupted that hominid existence. A study of marine sediments sampled off the coast of Portugal and published in Science, carried out by researchers from University College London (UCL), the Institute of Environmental Diagnostics and Water Studies (IDAEA-CSIC) and the IBS Center for Climate Physics of South Korea, has discovered that on that date an extreme glaciation took place, much colder and more persistent than previous ones.
The scientists extracted cores from the seabed corresponding to the last 1.4 million years and analyzed the composition of the different sediment layers using chemical and radioisotope methods. These analyzes revealed a worsening of environmental conditions starting 1.12 million years ago: the temperature of ocean water decreased by several degrees and samples of algae, foraminifera and pollen creatures indicate that a much stronger and more extreme glaciation occurred than previous.
The date also marks the beginning of a total absence of fossils and human tools that spans 200,000 years throughout Europe. Taken together, the data and results of the model used by the researchers suggest that in the Iberian Peninsula, and more generally, throughout Europe, hominid populations disappeared and there was no evidence of human existence again until 900,000 years ago, when New hominids, more resistant than the previous ones, once again expanded through the region, coming again from the Middle East.
The repopulation featured Homo antecessor, a more resistant species with evolutionary or behavioral changes that allowed survival under the increasing intensity. of glacial conditions. The remains found at the Gran Dolina site, in the Sierra de Atapuerca, dated to 800,000 years ago, belong to these new inhabitants.
Our guest, Joan Grimalt Obrador, has participated in the study and tells us during the interview about the research and the results obtained.
Joan Grimalt Obrador is a researcher at the Institute of Environmental Diagnosis and Water Studies (IDAEA) of the Higher Council for Scientific Research (CSIC).
Reference:
Vasiliki Margari, David A. Hodell, Simon A. Parfitt, Nick M. Ashton, Joan O. Grimalt, Hyuna Kim, Kyung-Sook Yun, Philip L. Gibbard, Chris B. Stringer, Axel Timmermann, Polychronis C. Tzedakis. Glacial extremes imply discontinuity of early hominin occupation of Europe. Science. DOI: 10.1126/science.adf4445
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