Ebook Description :

Geologists have done the same thing to geologic time by dividing the earths history into eras broad spans based on the general character of life that existed during these times and periods shorter spans based partly on evidence of major disturbances of the earths crust. For centuries scholars sought to determine earths age but the answer had to wait for careful geologic observation isotopic analyses of the elements and an understanding of radioactive decay by. Geologic age dating assigning an age to materials is an entire discipline of its own in a way this field called geochronology is some of the purest detective work earth scientists do there are two basic approaches relative age dating and absolute age dating. Remember that in relative dating scientists do not determine the exact age of a fossil or rock they look at a sequence of rocks to try to decipher when an event occurred relative to the other events represented in that sequence the relative age of a rock then is its age in comparison with other rocks