Traces of the Indians had destroyed the meteorite

Scientists from the University of North Carolina have found new evidence of a meteorite in North America about 13,000 years ago. The consequences of this decline are traditionally associated with the disappearance of American megafauna and Indian culture Clovis. The work is published in the journal Proceedings of the National Academy of Sciences.Magnetic microspheres called microscopic metal beads formed by melting and subsequent solidification of metals. They are often seen as evidence of meteorite falls along with impactites rocks formed as a result of such events.

The authors of this article conducted a structural analysis of the microspheres found in North America in the sediments of the age of about 13,000 years. The researchers first used in the analysis focused ion beam etching. This allowed the microspheres and cut to observe the internal structure. Was used to obtain images of a scanning electron microscope. In addition, the researchers conducted an additional X-ray analysis of the particles.

Installed structure microsphere indicating that their formation during metal was rapidly cooled. According to the chemical composition of particles found originate from the earth's crust. Preferably they consist of iron, aluminum and silicon, one bead has a significant concentration of rare-earth cerium.

According to scientists, the analysis of the microstructure and chemical composition indicates that although microspheres and come from the earth's crust, they were formed by meteorite. At least, the version space volcanic and anthropogenic origin, according to the authors is very unlikely.

Previously, the existence of a meteorite that fell to Earth about 13,000 years ago, as well as the scale of the consequences of its impact were the subject of much debate among scientists. In 2007, a group of researchers found in several places in North America deposits with microspheres presumably impact origin. Another group of scientists in 2009 attempted to refute the data, but, as the authors of this study used for this inappropriate allocation methodology microspheres. Doubts have been expressed in the interpretation and analysis of their chemical composition.

In March 2012, another group was found in central Mexico from the lake deposits of coal and impactites which, according to the author, and is the site of a meteorite.