have occurred several thousand years before Chicxulub. However, in response, a follow-up study in 2021 estimated using argon–argon dating that Boltysh formed about 65.39 ± 0.14/0.16 million years ago, 650,000 years after the Chicxulub catastrophe, and suggested that the fern spike was plausibly a result of the impact itself. The authors of the paper suggested that the impact may have disrupted recovery after the K/Pg extinction. References Further reading Grieve, R. A. F., Reny, G., Gurov, E. P., & Ryabenko, V. A. (1987). The melt rocks of the Boltysh impact crater, Ukraine, USSR. Contributions to Mineralogy and Petrology, 96(1), 56–62. Grieve R.A.F., Reny G., Gurov, E.P., Ryabenko V. A. (1985), Impact Melt Rocks of the Boltysh Crater, Meteoritics, v. 20, p. 655 Gurov, E. P., Kelley, S. P., Koeberl, C., & Dykan, N. I. (2006). Sediments and impact rocks filling the Boltysh impact crater. In Biological processes associated with impact events (pp. 335–358). Springer Berlin Heidelberg. Gurov E.P., Gurova H.P. (1985), Boltysh Astrobleme: Impact Crater Pattern with a Central Uplift, Lunar & Planetary Science XVI, pp. 310–311 Jolley D., Gilmour I., Gurov E., Kelley S., Watson J. (2010) Two large meteorite impacts at the Cretaceous-Paleogene boundary Geology September 2010, v. 38, pp. 835–838, Kashkarov L.L., Nazarov M.A., Lorents K.A., Kalinina G.V., Kononkova N.N. (1999), The Track Age of the Boltysh Impact Structure, Astronomicheskii Vestnik, v. 33, p. 253 Kelley S.P., Gurov E. (2002), The Boltysh, another end-Cretaceous impact, Meteoritics & Planetary Science, v. 37, pp. 1031–1043 Impact craters of Ukraine Paleocene impact craters Geography of Kirovohrad Oblast