Isochrons, single-crystal

Figure 10. Single-crystal internal isochron plot of the 26A l-26Mg evolution diagram for different areas with distinct 27Al/24Mg ratios within individual anorthite crystals from TS-21 (9) and TS-23 ( A. V-...

The fit of the data to a single isochron indicates that individual anorthites from both B1 and B2 inclusions are internally isotopically homogeneous despite large internal variations in Mg and Na content and extensive mineralogical alteration. The slope of the single-crystal isochron is the same as that of the B1 isochron. 

The microscopic spatial resolution of the ion probe enabled us to measure the isotopic composition at several points within individual crystals and these ion probe data establish the first single crystal isochron for areas with distinct 27Al/24Mg ratios. The Mg isotopic pattern within each B1 and B2 anorthite is individually consistent with a single (26A1/27A1)q ratio, suggesting... 

Fig. 3.12 Comparison of unirradiated, 100 °C and 470 °C irradiated samples of single crystal MgO.SALOs after isochronal annealing [52]. With kind permission of John Wiley and Sons and Professor Suematsu...

It is difficult to compare the shapes of the viscoelastic functions for single crystal mats and bulk crystalline polymer from the data of Figs. 16-1, 16-2, 16-S, and 16-6 without extensive recalculation under circumstances where approximation methods give poor precision because the functions vary so slowly with time or frequency cf. equation 40 of Chapter 4). Comparisons of the two types of samples will be shown for isochronal viscoelastic functions in Section B below. 

Whole-rock Rb-Sr isochron dates indicate that the Rennick Schist of the Daniels Range crystallized at about 532 20 Ma (Early Cambrian lUGS 2002) and that the sandy (psammitic) and clay-rich (pelitic) facies had elevated initial Sr/ Sr ratios of 0.7187 0.0009 and 0.7243 0.0009, respectively (Adams 1986). A Rb-Sr date of a single whole-rock sample reported by Faure and Gair (1970) was recalculated to 548 33 Ma based on initial ratios obtained by Adams (1986) and using the decay constant of Rb recommended by... 

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