Shocked quartz found at the K/T boundary



What killed the dinosaurs? This is the most popular question of the “Cretaceous/Tertiary (K/T) controversy,” which is concerned with the extinction some 65 m.y. ago of more than 75% of the world's existing floral and faunal species [Surlyk, 1980]. A popular hypothesis of their untimely demise is the impact of a meteorite [Alvarez et al., 1980]. However, despite the claim [Alvarez, 1983] that this has been proven, some serious doubts remain [Hallam, 1987; Officer et al., 1987]. A rival claim, that the dinosaurs were done in by a catastrophic volcanic eruption, has attracted some proponents and has some evidence in its favor, but that case is far from proven. However, it does have the advantage of having a definite event to point to the Deccan Traps in India. These are the largest continental flood basalts known from the Phanerozoic. According to recent studies [Courtillot et al., 1986; Feraud et al., 1988], the Deccan Traps were emplaced close to 65 m.y. ago. Is this timing a coincidence or are the two events (the mass extinction and the Deccan volcanism) related?