Fig. 2: Evolution of Li systematics in arc magmas for arcs of different crustal thicknesses. | Nature Communications

Fig. 2: Evolution of Li systematics in arc magmas for arcs of different crustal thicknesses.

From: Lithium systematics in global arc magmas and the importance of crustal thickening for lithium enrichment

Fig. 2

a Li (ppm) vs. SiO2. b Li (ppm) vs. residual melt fraction (F) as determined by the relative enrichment of K. c Li (ppm)/K (ppm) vs. SiO2. d Li (ppm)/Y (ppm) vs. SiO2. Arc magmas were divided into three crustal thickness groups (0–25 km, 25–50 km, and 50–75 km) based on calculated crustal thickness (see “Methods“). For each crustal thickness interval, samples were averaged in intervals of 2 wt.% SiO2 or 0.05 residual melt fraction. Error bars on Li, Li/K, and Li/Y represent two standard error (2se). In (a) and (b), solid and dotted lines show modeled residual melt compositions due to crystal fractionation for different initial Li content (Lio) and bulk partition coefficient (D) (see “Methods”). Pale green bar in (a) and (b) denotes average Li concentration of mid-ocean ridge basalt (MORB) from Gale et al.22. Pale blue bar in (d) shows the Li/Y ratio of MORB from Ryan and Langmuir9. The colored arrows in (a) show average Li contents of upper, middle, and lower continental crust from Rudnick and Gao61. Arc data are extracted from GEOROC56. Mid-ocean ridge data are from Keller et al.62.

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