The volume of the world’s oceans is 1,350,000,000 km3; total dissolved solids (T
ID: 111957 • Letter: T
Question
The volume of the world’s oceans is 1,350,000,000 km3; total dissolved solids (TDS) in the oceans is 35 g/L. Annual flow of water from world’s rivers entering the ocean is estimated to be 37,000 km3 /year. Assume the average TDS concentration in the rivers to be 12 mg/L.
Using a salt mass balance approach, determine the age of the Earth. First determine the total mass of salts (in kg) within the oceans; then find the annual salt load delivered to the global oceans (in kg/year). How old are the oceans using Halley and Joly’s technique? Discuss what assumptions went into this calculation (at least 3). Why do you think this approach underestimates the currently accepted age of the Earth (4.6 billion years, found via radiometric dating)?
Explanation / Answer
Our earth is billions of years old and is the creation which takes place in such an incident which was very very old as at that time non of the present living organisms were there. But not only the living but many non living object was also not there. This all we generally know about the earth as a basic idea of the age of our planet earth.
But now if we want to describe it in terms of the amount of any earth material and by knowing its quantity then it will be somewhere possible to determine the age of earth .
So now if we take the help of earth material like salt and by knowing the amount or volume of it to know the age then it will be as follows - according to your question information it was said that if the total volume of salt is about 35 g/l as TDS enter annually and the total volume of ocean water is given as 1350000000km3.
So annual flow rate to ocean from the rivers are 37000km 3. So the age is total volume multiply by salt Mass and divided by annual flow rate.
So age = time to fill up the volume by salt as TDS
age=(1350000000*35)/37000=4.4 billions years approximately.
The data calculation may be different so we would require to take the approx value.
To find the age by radioactive dating and it is accepted because to the fact that it is a method which directly proccess upon earth material and by knowing their age we can easily calculate the age of earth. It give precise accurate reading of age because The process is done on Earth materials which Were originated at that time when earth was initially formed. So it is accepted.
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