Applications of lead and strontium isotopic relationships to the petrogenesis of granitoid rocks, central Sierra Nevada batholith, California

Lead isotopes by LA-MC-ICPMS: Tracking the emergence of mantle signatures in an evolving silicic magma system

“…Secular eruption age-corrected Sr and Pb isotope trends within mafic and rhyolitic volcanic rocks from the Long Valley region, California (Sr data of Halliday et al, 1989;Davies and Halliday, 1998;Heumann and Davies, 1997;Heumann et al, 2002;Simon and Reid, 2005. Pb data of Chen and Tilton, 1991;Cousens, 1996;Halliday et al, 1989;Heumann and Davies, 1997;Heumann et al, 2002;Nielsen et al, 1991;Ormerod, 1988;Reid and Ramos, 1996; and this study). The intersection of trends defined by the mafic lavas and the pre-and postcaldera rhyolites support the idea of a common source component (''LVref'', see text).…”

“…Collectively these data suggest that the precaldera and postcaldera rhyolites evolved towards an end-member common to both systems and require both high and low d x Pb/ 206 Pb 0 crustal end-members. Possible crustal end-members for the Pb isotope compositions exist among eastern Sierran granitoids (Chen and Tilton, 1991;Cousens, 1996), as shown in Fig. 4.…”

Lead and strontium isotopes as monitors of experimental granitoid mineral dissolution

“…The calcite/apatite phase had a significant contribution to the whole rock dissolution only in the first ϳ150 h of the dissolution experiment, and because the 206 Pb/ 207 Pb and 87 Sr/ 86 Sr values of the output solutions were low during this period (Fig. 1a,b), it is reasonable to assume that the contribution at that stage was mostly from calcite, as a high proportion of apatite should have had elevated the 206 Pb/ 207 Pb values (Chen and Moore, 1982;Chen and Tilton, 1991;James, 1992;Mattinson, 1978). On the other hand, after ϳ1000 h apatite and not calcite was the main mineral inclusion controlling the release of Pb from the biotite ϩ chlorite-rich phase.…”

Tracing the mobility of individuals using stable isotope signatures in biological tissues: “locals” and “non-locals” in an ancient case of violent death from Central California

“…Unfortunately, 87 Sr/ 86 Sr in bedrock has not been extensively mapped in California. While some regions have been studied by geologists and other scientists (Barnett-Johnson et al, 2008;Hobbs et al, 2005Hobbs et al, , 2010Ingram and Lin, 2002;Ingram and Weber, 1999), and the age of some rock formations has been determined by Sr/Rb dating (Chen and Tilton, 1991;Cole and Basu, 1995;Kistler and Peterman, 1973), a state-wide map of Sr isotope ratios does not, to the best of our knowledge, exist. Existing data suggest there is a NeS gradient in Sr isotopes across the Sierra Nevada, with 87 Sr increasing to the North due to slightly older surface geology.…”