Fission track dating method

Instead of comparing the ratio of isotopes, the age of a rock is determined by visually counting fission tracks of U.Fission track dating, although an unusual radiometric dating process, is accurate when used correctly and correlated with other dating methods.In order to make fission tracks a useful method to date the earth, it must fit the criteria of good a natural clock.A note must be made that fission tracks are extremely thermally unstable (Geochronology Group 2005).The method has found particular application in estimating temperature history and long-term denudation rates in orogenic belts, rifted margins and more stable areas, providing a means of assessing the timing and volume of sediment being delivered to sedimentary basins, and as an estimator of hydrocarbon maturity potential.Fission-track analysis of U-bearing minerals (mainly zircon, apatite and sphene) is based on the natural decay by spontaneous fission of the U atoms, located within the mineral itself (Fleischer et al., 1975).

Fission tracks, as physical structures, are simply linear tracks in rock crystals usually about 10-6 meters long.Fission track dating, on the other hand, does not involve the measurement of daughter products, and the concentration of its parent isotope can be misleading because the parent element goes through other types of decay much more often than it goes through spontaneous fission.Unlike any other dating methods, however, fission tracks leave physical evidence of a radioactive process.It is well accepted that at high cooling rates the closure of the radiometric system takes place at higher temperatures.The latest estimations of the zircon partial annealing zone suggest temperature limits of ~390 – 170°C (Yamada et al., 1995) and of ~310 – 230 °C (Tagami and Dumitru, 1996; Tagami et al., 1998).

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Fission track dating method introduction

Fission track dating method

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