The Rock Record Flashcards
Define Geologic time scale
record of Earth’s history from 4.6 BYA to present time
Why is the geologic scale important
Enables scientists to find relationships among geological events, environmental conditions, and fossilized life forms
the 4 eons from oldest to youngest
Hadean, Archean, Proterozoic, phanerozoic
What is precambrian time
informal units of geologic time consisting of the first 3 eons during which the earth formed.
How much of Earth’s history does Precambrian time account for
90% of geologic time
Who is considered to be the “Father of Geology”
James Hutton
What is uniformitarianism
theory that geologic process occuring today have been occuring since Earth formed
what is Relative age dating
the age of an object in relation to the ages of other objects
What is absolute age dating
Method that enables scientists to determine the numeric age of certain rocks and other objects
what is radiometric dating
a method of determining the absolute age of an object by comparing the ralative percentages of a radioactive (parent) isotope, and a stable (daughter) isotope
Parent isotope
radioactive
Daughter isotope
stable
if you begin with 10g of a parent isotope, you would have how many grams after a half life
5g
After 2 half lives, how much daughter/parent isotope would be left
25%
What info does radiocarbon provide
helps determine the age of young organic objects by quantifying the amount of radioactive carbon remaining in the dead organism.
