Early attempts made to estimate Earths' absolute age Flashcards
1
Q
what was old belief about salinity of oceans
A
oceans were once fresh
2
Q
how was it thought that the oceans became saline
A
salt added by rivers (through erosion)
3
Q
salt calculation
A
amount of salt in ocean/amount added each year
4
Q
what was estimated ages of earth (salt in oceans)
A
90 million (inaccurate due to problems finding amount of salt)
5
Q
how was earth age estimated by rate of sedimentation?
A
if you know how long it takes to deposit 1m of sediment then you can work out age of earth from existing rocks
6
Q
problems with dating earth from sediment rates
A
not all sediment becomes rock
different rates of sediment = INACCURATE
