Zircon fission track dating Free couples russian web chat site
FT thermochronology is widely used for reconstruction of low-temperature thermal histories in upper crustal rocks.
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.
Apatite and zircon separates from the Fish Canyon Tuff (K-Ar age, 27.9±0.7 Myr), San Juan Mtns., Colorado, have been given to over 50 laboratories for fission-track dating.Accurate and precise age estimates can be obtained on glass by use of the isothermal plateau fission-track (ITPFT) dating method. Correction for partial track fading is achieved by heating the natural sample and its irradiated aliquot for 30 days at 150°C. The other problem is that uranium is particularly susceptible to weathering.
Now since all rocks are somewhat porous, and since we are pretty much obliged to date rocks from near the surface, it's hard to find instances in which uranium has not been lost.
This grain-specific technique is particularly suited to the dating of fine-grained, distal tephra beds and will greatly facilitate development of detailed chronologies of tephra-bearing sedimentary sequences located far from volcanic centres.