Extended Data Fig. 5: Model evolution of melt composition for varying BLIC bulk compositions (Tables S1, S2), to investigate the impact of possible cumulate processes.
From: A mid-crustal tipping point between silica-undersaturated and silica-oversaturated magmas
Each bulk composition undergoes fractional crystallisation to 94-95 % fractionation (dashed line), followed by subsequent in-situ batch crystallisation (solid line), as in Fig. 3 of the main text. The modelled bulk compositions and ‘cumulate-correction’ calculation details are given in the Supplementary Discussion, with panels (a) and (b) using alternative reported whole-rock measurements and panels (c) and (d) using ‘cumulate-corrected’ bulks. Whole-rock geochemistry12,14,28 for BLIC shown in coloured symbols following Fig. 1: orange shades for eastern lobe of Nechalacho Layered Suite (circle), Thor Lake syenite (diamond), Grace Lake granite (cross); blue shades for western lobe of Hearne Channel/Mad Lake granite (upwards triangle), Whiteman Lake syenite (pentagon) and Caribou Lake gabbo (inverted triangle).
