One of the more controversial environmental issues, which emerged in the final years of the Soviet era, was the plan to dam and reverse the flow of north-flowing rivers in order to irrigate the dry southern steppes. This scheme was roundly criticised by scientists and environmentalists at the time because of fears for the impact on the Arctic Ocean and global climate. It now appears that nature performed this experiment some 90,000 years ago.
This months issue of the Journal of Quaternary Science reports evidence based on years of fieldwork in Siberia by Professor Jan Mangerud, of the University of Bergen, Norway, which indicates that early in the last Ice Age, natural ice dams formed and drastically altered the drainage patterns of the region.
At the start of the ice age an ice sheet formed over the shallow Barents and Kara seas forming a natural dam. As the ice advanced onto the Siberian mainland, it blocked the flow of the northerly flowing rivers, including the Yenissei, Ob, Pechora and Dvina, which supply most of the Arctic Ocean with its freshwater. Huge ice-dammed lakes were formed which covered massive areas of Siberia. One of these on the western Siberian Plain was more than twice as large as any lake on Earth today. The overflows from these lakes were towards the south, into the Aral, Caspian and Black seas which were also connected by large rivers. The drainage of the Eurasian continent was thus reversed.
Joanna Gibson | alphagalileo
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Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.
Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
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A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
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In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
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