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Radioactive isotope with long half life would be the way to date a sample of rock that you suspect as being one of the earliest on Earth. Archaeologists very often use this method for checking the dates of the materials they excavate. I hope that this is the answer you were looking for and it has come to your help.
An aquifer<span> is an underground layer of </span>water<span>-bearing </span>permeable rock, rock fractures or unconsolidated materials (gravel<span>, </span>sand<span>, or </span>silt<span>) from which </span>groundwater<span> can be extracted using a </span>water well<span>. The study of water flow in aquifers and the characterization of aquifers is called </span>hydrogeology<span>. Related terms include </span>aquitard, which is a bed of low permeability along an aquifer,[1]<span> and </span>aquiclude<span> (or </span>aquifuge<span>), which is a solid, impermeable area underlying or overlying an aquifer. If the impermeable area overlies the aquifer, pressure could cause it to become a confined aquifer.</span>
