Figure 2: Strontium and neodymium dual isotope plot.
From: Dust outpaces bedrock in nutrient supply to montane forest ecosystems
Isotopic compositions of Sierra Nevada dust samples are plotted in context of literature derived potential source area isotopic compositions (a) Central Valley and Asia (b) including Sierra Nevada granite25,29,32. External reproducibility (2 s.d.) of new data are smaller than the symbol size; errors for literature data are 0.5–1.0 ɛNd. Symbols for the four sites match those in Fig. 1: circles are Shorthair (elevation ∼2,700 m); pentagons are Providence (elevation∼2,000 m); diamonds are Soaproot (elevation∼1,100 m); and squares are San Joaquin Experimental Range (elevation∼400 m). Colours reflect passage of time during the sampling interval: yellow (July), orange (August) and red (September). The relatively radiogenic composition and small range in ɛNd indicates that local, Sierra Nevada granite provides negligible dust emission and deposition to these sites (b); dust is a combination of regional Central Valley sources and global Asian sources (a).
