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Science. 2003 Jun 13;300(5626):1734-7.

Impact ejecta layer from the mid-Devonian: possible connection to global mass extinctions.

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Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell Geoscience Complex, Baton Rouge, LA 70803, USA.


We have found evidence for a bolide impacting Earth in the mid-Devonian ( approximately 380 million years ago), including high concentrations of shocked quartz, Ni, Cr, As, V, and Co anomalies; a large negative carbon isotope shift (-9 per mil); and microspherules and microcrysts at Jebel Mech Irdane in the Anti Atlas desert near Rissani, Morocco. This impact is important because it is coincident with a major global extinction event (Kacák/otomari event), suggesting a possible cause-and-effect relation between the impact and the extinction. The result may represent the extinction of as many as 40% of all living marine animal genera.

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