Меловой период

Charbonnier G., Morales C., Duchamp-Alphonse S., Westermann S., Adatte T., Föllmi K.B. (2017) Mercury enrichment indicates volcanic triggering of Valanginian environmental change // Scientific Reports 7, Article number: 40808 (2017)
doi:10.1038/srep40808

http://www.nature.com/articles/srep40808