E&S SCI 17 Lecture 17: Lecture 17.docx

• School: UCLA
• Department: Earth, Planetary, and Space Sciences
• Course: E&S SCI 17
• Professor: Christopher Eagle

Document Summary

First big geological boundary defined all scientists that look at this agree on two things: around kt there is evidence of gradual climate change and there is evidence that there was some sudden catastrophic event most important discovery: there was a layer in the ground that had high levels of iridium on earth surface today there is very little iridium but extraterrestrial places have high concentrations of it this suggests an asteroid. Silicon minerals that make sort of perfect spheres due to melting of rock by energy of an asteroid or comet impact and expulsion into the atmosphere soot particles were found in boundary clay the amount of pollen drops significantly as iridium increases we also see that ferns may have not shown a big response to the coming of angiosperms flowering plants in particular suffered a big decline with the boundary fullerines (the molecular cage of carbon atoms) found in boundary layers contained elevated 3he suggesting extraterrestrial origin.