Some water-laid deposits do too.Īll sediments and soils contain trace amounts of radioactive isotopes including uranium, thorium, rubidium and potassium. ![]() Eolian deposits, such as sand dunes and loess, usually (but not always) satisfy this criterion. ![]() The accuracy obtainable under optimum circumstances is about 5%.Ĭrucial to the optical dating method is that there was adequate daylight exposure to the mineral grains before they were buried. Ages can be obtained outside this range, but they should be regarded with caution. ![]() ![]() Ages can be determined typically from a few hundred years to 100,000 years, and can be reliable when suitable methods are used and proper checks are done.
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