NATS 1540 Study Guide - Quiz Guide: Central Atlantic Magmatic Province, Shocked Quartz, Anoxic Waters
Document Summary
The end cretaceous mass extinction 65 million years ago (65ma): caused by an asteroid impact in the yucatan peninsula (the alverez asteroid theory). Supported by iridium at the cretaceous-tertiary boundary, together with shocked quartz and tektites. This extinction eliminated the dinosaurs, about 40% of marine genera and 16% of families including several microfossil groups, some bivalves and the ammonites. Mososaurs and other marine reptiles went extinct as well. The end-triassic mass extinction 199 ma: caused by a rapid rise in sea level which coincides with the elimination of some. 53% of genera and 22% of marine families. Particularly affected were cephalopods, brachiopods, clams and some snails. The leading candidate for the trigger of the end-triassic extinction is massive volcanism, known to geologists as the. Central atlantic magmatic province because it spans the atlantic margin. This first pulse seems to have had little long-term impact on life, for many late permian fossil assemblages look much like those before the extinction.
