Impact ejecta layer from the mid-Devonian: possible connection to global mass extinctions.
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.
Ellwood
Brooks B
BB
Department of Geology and Geophysics, Louisiana State University, E235 Howe-Russell Geoscience Complex, Baton Rouge, LA 70803, USA.
Benoist
Stephen L
SL
El Hassani
Ahmed
A
Wheeler
Christopher
C
Crick
Rex E
RE
D000818:Animals; D002980:Climate; D017753:Ecosystem; D019015:Geologic Sediments; D008280:Magnetics; D019110:Meteoroids; D009018:Morocco; D012623:Seawater; D013995:Time