Fossils & Ruins 

Genome study presents new way to track historical demographics of US populations

Sharon Browning of the University of Washington and colleagues developed a method to estimate historical effective population size, which is the number of individuals who pass on their genes to the next generation, to reveal the shifting demographic history of U.S. populations during the last several thousand years. They report their findings in a new study published May 24th, 2018 in PLOS Genetics.

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Fossils & Ruins 

Cold production of new seafloor

A mountain range with a total length of 65,000 kilometers runs through all the oceans. It marks the boundaries of tectonic plates. Through the gap between the plates material from the Earth’s interior emerges, forming new seafloor, building up the submarine mountains and spreading the plates apart. Very often, these mid-ocean ridges are described as a huge, elongated volcano. But this image is only partly correct, because the material forming the new seafloor is not always magmatic. At some spreading centres material from the Earth’s mantle reaches the surface without being melted. The proportion of seabed formed this has been previously unknown.

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