Dating on earth wiki
One must also know the history of the method and how it came to be.One very handy aspect of this method is that measuring salt in the oceans is quite easy because of its abundance.If a somewhat constant rate of accumulation of the salt is known, and the present amount of salt in the water is known, then a simple algebraic calculation would render the age of that particular body of water.This is exactly what many people have tried to do over the years.This assumption is false as it has been later proved that elements of the ocean are being constantly recycled and leave the water.As plate tectonics shapes our Earth, sea beds rise and evaporate, leaving large salt deposits.
What makes the ocean salty is that when water evaporates off of the ocean, it leaves its load of dissolved salt behind and becomes fresh.One such failed dating technique is measuring the present salt content of the ocean to create a time scale to determine how long it has existed.This technique was introduced nearly 300 years ago, and it was researched by many prominent scientists for several hundred years until it fell out of favor because of obvious drawbacks in the method.Reade came up with a calculation that it would take 25 million years for the sulfates of calcium and magnesium to reach their present concentrations in the oceans. John Joly calculated an age of 99.4 million years in 1899.Ten years later, Joly revised his equations and calculated the age to be between 80 and 150 million years old. Becker found the age of the Earth to be between 50 and 70 million years old when he used the salt clock method in 1910 (40-41).