Figure 4: Hafnium and neodymium dual isotope plot.
From: Dust outpaces bedrock in nutrient supply to montane forest ecosystems
Arrays of Earth’s oceans, sediments and igneous rocks (compiled by Bayon and others40) are plotted with the hafnium (Hf)-neodymium (Nd) isotope compositions of dust measured in this study. All samples lie within the zircon-free and zircon-bearing array, suggesting that they originate from a combination of near (regional Central Valley) and far (Asian) dust sources. Symbols for the three 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).
