Photomicrographs and SEM-CL images (insets) showing the textural settings of zircon in thin section in the Upper Border Series of the Skaergaard intrusion (all scale bars are 100 μm). (a) Skeletal zircon in LZa’ (SK08-190, XPL). (b) Irregular zircon crystal between quartz and alkali feldspar in LZa’ (SK08-190, XPL). (c) Skeletal zircon in an interstitial granophyric pocket between two plagioclase primocrysts in LZa’ (SK08-190, PPL). (d) Euhedral zircon in contact with biotite (altered to chlorite and ilmenite) and quartz in LZb’ (SK08-10, PPL). (e) Anhedral zircon in contact with altered biotite in an interstitial pocket containing granophyre and polyphase mineral assemblages in LZc’ (SK08-124, XPL). (f) Equant, euhedral zircon grains in an interstitial pocket containing altered biotite, alkali feldspar and quartz in MZ’ (SK08-137, PPL). (g) Skeletal zircon hosted in a large interstitial pocket in UZa’ (SK08-158, XPL). (h) Two zircon grains within a large polyphase pocket in UZa’ (SK08-158, PPL). (i) Two skeletal zircon grains hosted in a large granophyric pocket in UZb’ (SK08-154, XPL). (j) Elongate, euhedral zircon containing fine-grained inclusions hosted in a large granophyric pocket in UZb’ (SK08-154, XPL). (k) Acicular zircon in a quartz-dominated interstitial pocket in UZb’ (SK08-33, XPL). (l) Cluster of acicular zircon crystals hosted in a large interstitial granophyre pocket in UZc’ (SEB87-212B, XPL). Mineral abbreviations: Afs = alkali feldspar, Ap = apatite, Bt = biotite, Ilm = ilmenite (+ titanomagnetite), Pl = plagioclase, Qz = quartz and Zrn = zircon. Photomicrograph abbreviations: PPL = plane-polarized light and XPL = cross-polarized light.