Diagrams of Ti vs Hf in zircon for all Skaergaard intrusion samples, granophyres, sills, and related rocks. The dashed horizontal lines represent Ti-in-zircon temperatures (aSiO₂ = 1 for all samples, aTiO₂ = 1 for cumulates, aTiO₂ = 0.3–0.6 for granophyres and sills). The average 2σ uncertainty of Ti and Hf analyses (smaller than symbol size) from all filtered samples is shown as an inset in (f). (a) Upper Border Series LZa’ (SK08-190), LZb’ (SK08-124), and LZc’ (SK08-128) with inset box outlining trace element fields for each sample. (b) UBS MZ’ (SK08-137), UZa’ (SK08-158), UZb’ (SK08-154), and UZc’ (SK08-27, SEB87-212B). (c) Layered Series LZa (458245, SEB87-227A) and LZc (SEB87-231B). (d) Marginal Border Series LZc^* (SEB87-248). (e) Sandwich Horizon from Kilen (SK08-110, SK08-104). (f) Sandwich Horizon from Basistoppen (SK11-56). (g) Related rocks: Precambrian gneiss (SK11-131) and contaminated sample of LZa^* (SEB87-242, PPL). (h) Sydtoppen sill (SK08-35) and Tinden sill (SK11-190). (i) Granophyres in UZc (SEB87-215, 458649) and UZc’ (SK08-99) with inset boxes outlining trace element fields for each sample. (j) Granophyre in UZa (SEB87-211). Arrows indicate steeply inclined fractionation trends of strongly decreasing Ti with increasing Hf.