Fig. 1. Garnet compositional maps and profiles.

Color-enhanced wavelength-dispersive spectrometer (WDS) x-ray count maps for Mg (top row) and Mn (middle row) in garnets from Ring Mountain. Decreasing Mg and Mn content are indicated by yellow-green-blue-black color progression. Spots give location of Raman quartz analyses and are colored according to peak position (±1.5 cm⁻¹ about 470.9 cm⁻¹ for CA13-01; ±1.5 cm⁻¹ about 470.2 cm⁻¹ for CA13-05A; see data in Fig. 3D). Transparent spots correspond to partially transparent analyses in Fig. 3D. Spot size indicated is larger than the actual ~1-μm spot. White rectangles show notable zones with varying Raman response associated with compositional zoning boundaries (blowups provided in the Supplementary Materials). Dashed white ellipses highlight examples of zoning embayments/incursions. Gray backscattered electron (BSE) images indicate locations of quantitative (WDS) electron microprobe traverses at the bottom of the figure. Regions with steep compositional gradients in the traverses are indicated by vertical gray bands (with length scale indicated).