Iron, zinc, magnesium and uranium isotopic fractionation during continental crust differentiation: The tale from migmatites, granitoids, and pegmatites

Fe and Si isotope variations at Cedar Butte volcano; insight into magmatic differentiation

“…These results are in good agreement with previous studies (Fig. 2) reporting Fe isotope signatures in igneous materials (Poitrasson and Freydier, 2005;Schuessler et al, 2009;Schoenberg and von Blanckenburg, 2006;Teng et al, 2008;Heimann et al, 2008;Telus et al, 2012;Sossi et al, 2012). Permil δ 30 Si range from −0.31 for the most mafic end-member from CM to −0.10 for the most differentiated rhyolite from BSB.…”

A modern framework for the interpretation of 238U/235U in studies of ancient ocean redox

“…It is assumed that biogenic carbonates have a δ 238 U similar to the open ocean composition (−0.4h, see Section 4.1) and a detrital δ 238 U composition of −0.3h. This detrital composition may be variable but is assumed to be close to that of crustal materials like granites and basalts (Stirling et al, 2007;Telus et al, 2012;Weyer et al, 2008). Uncertainty estimates are scaled from the measurement error and a magnifying factor related to (1) the relative amount of U in the detrital versus the reduced authigenic fraction and (2) the measured δ 238 U relative to the composition used for the detrital correction (SOM Table).…”

Isotope Fractionation Processes of Selected Elements

“…These authors suggested that exsolution of fluids has removed light Fe isotopes causing the enrichment of SiO 2 -rich granitoids. Telus et al (2012) argued that exsolution alone cannot explain the high δ 56 Fe values in all granitoids, instead fractional crystallization seems to be the major cause of 56 Fe enrichment.…”