Pseudo-isochron

In contrast, Esperanca and Crisci (1995) and Trua et al. (1998) propose that magmatism in the Sicily Province is derived from young lithosphere that was enriched by addition of asthenosphere-derived melts. As recalled earlier, this is a relatively young process, which occurred during Permian-Triassic times. The young age of metasomatism is supported by Sr-Nd isotopic studies on the Iblei xenoliths, which give a pseudo-isochron of about 200 Ma (Tonarini et al. 1996). 

It is essential to be able to quantify the spots in order to use TLC as a quantitative method of analysis (Fig. 5.5). This is done by scanning the plate with a densitometer that can measure either absorption or fluorescence at one or many wavelengths. This instrument produces a pseudo-chromatogram that contains peaks whose areas can be measured. This corresponds to an isochronic image at the end of the separation. 

This is an example of strain-limited design. We apply the pseudo-elastic design method, specifying the duration of loading as S hours (which is 18000 seconds). In order to determine the modulus, we need the isochronous stress-strain curve for 18000 s. Substituting in the equation,... 

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