Apatite helium dating Userplane chat sex free
although the specific mineral he had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August Rammelsberg. This tendency is reflected in the mineral's name, which is derived from the Greek word απατείν (apatein), which means to deceive or to be misleading.
Apatite is one of a few minerals produced and used by biological micro-environmental systems.
Several studies suggest that the composition of the apatite does not appear to affect the sensitivity of the He closure temperature (Wolf et al., 1996; House et al., 1999), in contrast to the effect of Cl contents on AFTA annealing kinetics. Journal of Geophysical Research, 105 (B2), 2903-2914.
More recently, measurements of (U-Th)/He ages in samples from hydrocarbon exploration boreholes in the Otway Basin of S. Australia (House et al., 1999) have confirmed this general pattern of behaviour.
Their results also suggest that, in general, helium diffusion systematics derived from laboratory measurements can be extrapolated to geological conditions with confidence, although the exact details details remain to be quantitatively assessed.
Detailed experimental measurements at Caltech have led to further refinements in understanding the diffusion systematics of Helium in apatite (Farley, 2000).
This work, focussed on the much-studied Durango apatite, has suggested that diffusion systematics are controlled by the physical grain size.
By modelling ages through a variety of different thermal history scenarios, it is possible to define the range of histories giving predictions which are consistent with measured ages.