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Two deadlines for extinction
The extinction between the Cretaceous and the Paleogene that wiped out the non-avian dinosaurs 66 million years ago was correlated to two extreme events: The impact of Chicxulub was produced at at about the same time that huge quantities of lava were escaping Deccan traps (see Burgess Perspective). Sprain et al. used argon-argon dating of the volcanic ash from the Deccan pits to explain that a regular eruption of flood basalts occurred mainly after the impact of Chicxulub. Schoene et al. used the dating of uranium-lead zircons from the ash beds and concluded that four large magmatic impulses occurred during the basalt eruption, the first of which preceded the impact of the Chicxulub. Whatever the order of events, better timing constraints and eruption rates will help elucidate the influence of volcanic gas on the climate.
Science, this number p. 866, p. 862; see also p. 815
Abstract
A temporal correlation between some continental flood basalt eruptions and massive extinctions has been proposed to indicate a causal link, volatile eruptive discharge leading to degradation and extinction of the environment. We tested this model for flooded basalt province of Deccan Traps, which, along with the impact of the Chicxulub bolide, is involved in the extinction of the Cretaceous-Paleogene (K-Pg) there are about 66 millions of years. We estimated Deccan blowout rates with uranium-lead zircon (U-Pb) geochronology and resolved four high-volume eruptive periods. According to this model, peak eruption rates occurred before and after the extinction of K-Pg, one of those impulses beginning tens of thousands of years before the impact and l & # 39; 39, extinction of the car. These results support the extinction models that integrate the two catastrophic events as factors of environmental deterioration associated with the extinction of K-Pg and its consequences.
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