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Fig. 4 | Earth, Planets and Space

Fig. 4

From: Middle Miocene forearc alkaline magmatism in Amami-Oshima Island, central Ryukyu Arc: implications for paleoreconstruction of Shikoku Basin

Fig. 4

Geochemical discrimination diagram of basaltic rocks in Amami-Ohshima Island. a Total alkali vs. SiO2 plot (after Le Maitre 2002). The dashed line separates alkalic and subalkalic rocks from Miyashiro (1978). Error bars indicate standard deviations (two sigma) for calibration lines of the XRF analyses (Additional file 2: Table S2). b Geochemical discrimination diagram using Th and Nb. Modified from Saccani (2015). Subscript ‘N’ refers to values normalized to normal mid-ocean ridge basalt (N-MORB). E-MORB: Enriched MORB. The two standard deviations of repeated sample analyses are less than the size of the symbols (Additional file 2: Table S3)

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