Thus, the concentration of samarium and neodymium in rocks, and the ratios between different isotopes of neodymium, can reveal how long ago a rock sample crystallized from magma, and thus how old it is.
36 (2001) 167-175] recently presented a method of determining the cooling rates of rocks from the difference between the core and bulk ages of a crystal, as determined by a single decay system.
We have micro-sampled the garnet crystals over specific radial dimensions, and measured the Nd isotopes of these small sample masses, as Nd O via solid source mass spectrometry, to determine the Sm-Nd age difference between the core and bulk crystals.
Cofall became football coach at Roman Catholic High, and in 1922, he coached his squad to an Eastern prep-school championship.
Cofall wrote Rockne, then the successful head coach of the Irish, about three superb players from his Roman Catholic team – quarterback Vince Mc Nally, end Joe Maxwell and tackle Joe Boland.
Using a peak metamorphic P-T condition of 8 ± 1 kbar, 820 ± 30°C [Spear and Parrish, J. 37 (1996) 733-765], the core (67.3 ± 2.3 Ma) and bulk (60.9 ± 2.1 Ma) ages of the British Columbian garnet sample yield a cooling rate of 2-13°C/Myr, which is in very good agreement with the cooling rates that we have derived by modeling the retrograde Fe-Mg zoning in the same garnet, and assuming the same peak metamorphic P-T condition.