GEL 1 Lecture Notes - Lecture 4: Himalayas, Gnu Compiler Collection, Oceanic Crust
Document Summary
Oldest mineral: zircon grain 4. 4 billion years old found in a rock. has core portion that was incorporated from a previous mineral. How we get the age of a rock. Relative age: determination of age based on proximity to other items/times. Something is older / younger than something else (but doesn"t give exact age. Most useful for fossils through time and broad scale features. Fossils change over time,so we know it can be relatively older or younger than another fossil nearby. Absolute age: a precise number/age for a geologic event or deposit. Always has a +- because error in precision. Can determine when dinosaur lived based on when dinosaur died if happened around the time of eruption. Stable: do not change over geologic time (at least as long as the earth has been around, probably through the entire universe) Radioactive decay is not linear, it is exponential/logarithmic.
