Radiometric dating detrital minerals sedimentary rocks gives

Posted by / 19-Nov-2017 05:51

Radiometric dating detrital minerals sedimentary rocks gives

Ages can be measured with an analytical uncertainty of 1 to 2% for rocks as young as 100 Ka or older than 3000 Ma.Rubidium, because of its geochemical association with potassium, is also found in a wide range of rocks and minerals.Even though lead may be lost from the system, in most cases a cogenetic suite of zircons will preserve the age of crystallization.Measurement of lead isotope ratios in whole-rocks, minerals and ores has long been recognized as an important technique in studying the origins of igneous and metallogenic suites.Precise corrections can be made for the amount of pre-existing daughter product, if any, incorporated in the mineral at the time of its formation, and the amounts of the isotope introduced in the lab procedure.The relatively high abundance and widespread distribution of potassium in the earths crust enables the potassium-argon (K-Ar) technique of age determination to be applied to common rocks and minerals.Volcanic glass often contains a significant proportion of potassium, and, therefore, argon.Glass, however, may not retain argon quantitatively over extended periods of time, and any trend towards devitrification will result in argon leakage.

Age control is vitally important in geological, petrogenetic, tectonic and geomorphological studies and for stratigraphic correlations.The differing half-lives for the radioactive U means that two systems can be used to calculate ages and when plotted against each other provide a test for closed system behaviour; i.e.when there is concordancy of the two uranium-lead ages, giving rise to a conventional concordia diagram (a plot of The main advantage of the uranium-lead technique rests with the resistance of accessory phases, notably zircon, to post-crystallization disturbances and alteration.However, young volcanic rocks (Cenozoic) with moderate amounts of undevitrified glass, appear to have given reliable K-Ar whole-rock ages.Other minerals have been investigated, with mixed success.

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there is no loss or gain of either parent or daughter nuclide except that produced by the radioactive decay of one to the other.