In 1899, John Joly calculated the total mass of dissolved salt in the ocean in o
ID: 802483 • Letter: I
Question
In 1899, John Joly calculated the total mass of dissolved salt in the ocean in order to estimate that the minimum age of the ocean was 80-100 million years. To duplicate Joly's calculations, we know that the numerator for his calculations is 1.4*10^21 kg of salt for the total mass of dissolved NaCl. Estimate the denominator (mean annual input of salt) using the annual runoff rate from Figure 1.15 multiplied by the average river salt concentration (footnote to Table 5.4) multiplied by the percentages of river water input salt that are a) dissolved sodium plus dissolved chloride ions; b) all dissolved ions. When you divide the numerators by the respective denominators, what are your answers?
Explanation / Answer
1.1*10^8 tons/year= input of chloride ions from continents to oceans
58= atomic mass of Nacl
Mean annual input of Nacl=58/35*1.1*10^8tons/year
=1.6*1.1*10^8tons/year
since 1 ton=approx 1000 kg
=1.6*1.1*10^8*10^3
=1.76*10^11
=1.8*10^11kg/year
Now Mean annual input of NaCl salt/total mass of dissolved NacL
=1.8*10^11/1.4*10^21kg
=1.28*10^11*10^-21
=1.3*10^10kg
The total mass of dissolved sodium and chloride ions in the ocean