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The other 28 are radioactive and include some which decay by proton emission.The isotope dilution technique is applied in the dating of U- and Th bearing minerals in order to determine the concentrations of uranium, thorium and lead.As important as these factors are, it is unlikely that zircon dating would have achieved its present popularity had it not been for the major advances that have been made in U-Pb microchemistry and mass spectrometry, particularly over the last 20 years (e.g. Despite the enormous amount of zircon U-Pb data now available, some very basic questions about the nature and causes of isotopic disturbance (discordance) and the preservation of older isotopic systems in younger zircon populations (inheritance) have yet to be answered (Williams, 1992).Because zircon is resistant to physical and mechanical degradation and ages derived from detrital zircon analyses reflect the characteristics age spectrum of primary source rocks, and so detrital grains of zircons in sedimentary rocks are also important samples for age dating (Bruguier et al., 1997).

radiometric dating detrital minerals sedimentary rocks gives-65

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When in pegmatites, zircons contain more of these elements than they do in normal igneous rocks.

As a result, it is feasible to regard the decay of the uranium and thorium isotopes in minerals having secular equilibrium as if it took place directly to the respective Pb isotopes.

Pb), but the element actually has 32 isotopes in all.

In geochronological investigations of rock systems, methods involving isotope chemistry and mass spectrometry have evolved as precise and useful techniques for analysis of a number of natural radioactivity relationships (Silver and Deutsch, 1963). (1952) suggested that one of the most attractive phases in common rock systems for studying these three isotopic decay relations was zircon.

They proposed the so-called lead-a method, or Larsen method, a non-isotopic method of age determination. (19) studied the numerous activity, size, zoning, and other characteristics and defined the applicability and problems of U-Th-Pb systems in zircons in age-determination studies.

The isotopic composition of lead is determined by using a suitable mass spectrometer.