This paper examines sediments of Lake Cuitzeo of central Mexico, and interprets very strange components of a strange unusual layer of materials dated to the beginning of the Younger Dryas. This unique lacustrine carbon rich layer posesses traces of microspherules which have been interpreted as evidence of a cosmic impact. Data was attained from a 27 meter deep core, of which the area of concern is a 10 centimeter thick layer 2.8 meters in depth which is extremely rich. This layer is dated to 12900 years before present, and seems to have been deposited simultaneously with independent environmental changes. These impact indicator sediments, nanodiamonds and microspherules, all peak in abundance directly below a layer of extremely abundant charcoal. The layer of abundant nanodiamonds is aligned with the onset of the Younger Dryas, and no terrestrial processes pose any explanation for their abundance. These findings are consistent with many other cores taken across North America, Europe, and Greenland. Further study is needed to determine if the hypothesized extraterrestrial objects resulted in an airburst or surface impact 12.9ka, but some combination of the two is certainly possible.
Lake Cuitzeo is the 2nd largest lake in Mexico, over 300 square kilometers. And along the Trans Mexico Volcanic Arc, a tectonically active region, the lake lies at a very high elevation above 1800 meters. The core drilled in this lake was 10 centimeters in diameter, as extracted in 1997.
The leading hypothesis asserts that such an impact would be the result of Earth’s encounter with a dense debris field from a fragmenting comet. It has been proposed that a likely airburst coupled with small surface impacts would leave observable debris on more than 10% of Earth’s surface. The Taurid Meteor Stream has been the primary culprit of this source of debris, possessing 19 near Earth asteroids with diameters up to 5km.
Magnetic Impact Spherules- scale represents depth
Israde-Alcántaraa, Isabel, James L. Bischoffb1, Gabriela Domínguez-Vázquezc, Hong-Chun Lid, Paul S. DeCarlie, Ted E. Bunchf, James H. Wittkef, James C. Weaverg, Richard B. Firestoneh, Allen WestI, James P. Kennettj, Chris Mercerk, Sujing Xiel, Eric K. Richmanm, and Charles R. Kinzien. “Evidence from Central Mexico Supporting the Younger Dryas Extraterrestrial Impact Hypothesis.” Proceedings of the National Academy of Sciences. National Acad Sciences, n.d. Web. 17 Apr. 2017. <http://www.pnas.org/content/109/13/E738.full>.