martes, 24 de julio de 2012

RV: New evidence reveals Neanderthal extinction was not caused by climate change

Fuente: Royal Holloway, University of London home
Expuesto el: martes, 24 de julio de 2012 13:19
Autor: Royal Holloway, University of London home
Asunto: New evidence reveals Neanderthal extinction was not caused by climate change



Tiny glass fragments from a 40,000-year-old volcanic eruption suggest Neanderthals were wiped out by competition with modern humans and not by climate change. Picture by Suzanne MacLachlan

Research by academics at Royal Holloway, University of London provides new information that may settle a long-standing argument about the cause of the demise of Neanderthals.

The project, led by Professor John Lowe from the Department of Geography| at Royal Holloway, was based on the study of volcanic ash layers and indicates that climate was not the major factor in the Neanderthals' demise but instead the early modern humans had already started to decline long before a massive volcanic eruption plunged Europe into deep freeze.

The new evidence has emerged from the RESET project|, a collaborative initiative between members of staff in the departments of Geography and Earth Sciences| at Royal Holloway, the Natural History Museum, Oxford University and the University of Southampton. Their findings are published in the journal Proceedings of the National Academy of Sciences this week.

The novel element of this project is its ability to link archaeological and environmental records precisely, using invisible (to the naked eye) layers of volcanic glass, termed ‘cryptotephra’, that can be assigned to known volcanic eruptions using geochemical methods. The methods of detection and analysis of these cryptotephra layers have been pioneered at Royal Holloway and Oxford.

The researchers found that early modern humans were more resilient to environmental crises than previously supposed and concluded: "Our evidence indicates that, on a continental scale, modern humans were a greater competitive threat to indigenous populations than the largest known volcanic eruption in Europe, even if combined with the deleterious effects of climate cooling."

Professor Lowe adds: “The RESET team has been building a ‘lattice’ of European volcanic time-lines stretching back over the last 100,000 years, of which the CI is only one. Cryptotephra layers are more abundant and ubiquitous than previously imagined. The lattice is far from complete, but is already bearing fruit, and its legacy will have profound scientific impacts for years to come.”

Professor Martin Menzies, from the Department of Earth Sciences at Royal Holloway, comments: “The potential of this approach is not confined to the improvement of the chronology of archaeological and environmental events, but also has practical applications with respect to hazard assessment, such as clarifying the recurrence activity of different volcanic centres and predicting the spread of ash clouds composed of minute glass shards, such as that from Iceland which caused such havoc to air and other services in 2010."

Posted on Tuesday 24th July 2012

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