Fig. 4: Three-endmember mixing plots of Nd and Hf isotopes (εNd, εHf) in the Amazon estuary. | Nature Communications

Fig. 4: Three-endmember mixing plots of Nd and Hf isotopes (εNd, εHf) in the Amazon estuary.

From: Overlooked riverine contributions of dissolved neodymium and hafnium to the Amazon estuary and oceans

Fig. 4

Three-endmember mixing relationships of εNd (a) and εHf (b) calculated based on the 143Nd/144Nd and 176Hf/177Hf ratios with corresponding Nd concentrations ([Nd]) and Hf concentrations ([Hf]) and their salinities of three dissolved sources. The open squares and triangles represent the εNd signatures of the Fe–Mn oxyhydroxide fraction and of the total residual suspended particulate matter (SPM) from the Amazon River and Pará River, respectively. εNd (c) and εHf (d) distributions in the Amazon estuary against [Nd] and [Hf], respectively, showing the large-scale estuarine removal of Nd and Hf. The solid lines represent conservative mixing between the freshwater and seawater endmembers. The dashed lines above and below the corresponding solid line represent uncertainties in the estimation of the εNd and εHf endmember values. Error bars correspond to the 2 standard deviations of the εNd and εHf measurements.

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