GEOL 2207 Lecture Notes - Hatching, Photosynthesis, Deccan Traps
Document Summary
Case study, the k/t extinction (or k/p) 65 ma. K/t extinction: describe the character of extinctions at the k/t boundary. At least 50% of all species lost. Not just terrestrial species, marine fauna suffers: ammonites/marine reptiles 80-90% lost: discuss the evidence used to support the k/t impact. Water and luis alverez = latest cretaceous clay layer, enriched in iridium (iridium anomaly and clay layer is global) Fern spores vs. pollen: ferns first to colonize after fire impacted landscape (spores act as a proxy for forest fires: after k/t, massive increase in spike in the % of spores in sediments that are from ferns. Soot layers associated with the iridium layer, evidence of massive global fires. Tektites: natural glass produced by melting rocks during impact. Shocked quartz: another impact feature, cross-hatched lines = stress lines in the quartz. Tsunami deposits: evidence of almost global tsunami activity at end of cretaceous: describe the location and probable nature of the k/t impactor.
