Dating earth Flashcards
Dating assumptions that must be followed (5 of them)
1) The system must be closed. Neither parent or daughter atoms have been added or removed
2) The value of the decay constant must be known
3) Must accurately measure D & N
4) Must know D, And in some systems this equals 0
5) There are safe assumptions but they are specific
Earliest events of earth in order
age of solar system (4.567 B.Y.)
earth formation (4.5 B.Y.)
oldest mineral grains (4.4 B.Y.)
oldests rocks
Lots of rocks (3.8 B.Y.)
Earths geological time scale in order
Haden
Archean
Proterozoic
Precambrian (Archean + Proterozoic)
Phanerozoic (last 545 years)
The C isotopes that are used in identifying ancient life
- Positive values indicate 13C
- Negative values indicate 12C
Photosynthesis ______ 12C so living things have negative concentrations of ____
Removes
13C
