Primary (Mn,Fe,Ta,Nb)-bearing cassiterite with less than or equal to 0.21 wt.% ZrO2 and less than or equal to 0.05 wt.% HfO2 crystallized during the consolidation of the Archean Annie Claim #3 zoned, lepidolite-subtype granitic pegmatite, southeastern Manitoba, in amounts increasing from the outer to the inner pegmatite zones. Rare inclusions of tantalite and ferrotapiolite originated from transient local saturation in these phases. Sparse early cassiterite from the outer intermediate zone is rather rich in substituting elements and in part Fe-dominant, whereas the more abundant late cassiterite from the lepidolite core is strongly Mn-dominant and poor in the substituents. Exsolution in the primary cassiterite generated granular zirconian-hafnian ferrowodginite and wodginite enclosed in veinlets of substituent-depleted cassiterite. The Fe/Mn and Nb/Ta values of the wodginite phases mimic those of the primary cassiterite across the pegmatite zones, and Zr/Hf perceptibly decreases from the outer zones inward. Maximum contents of ZrO2 and HfO2 (5.98 and 1.59 wt.%, respectively; 0.31 Zr and 0.04 Hf apfu) are the highest so far encountered in wodginite-group minerals. These maxima characterize wodginite exsolved from early cassiterite; the levels drop off in wodginite exsolved in late cassiterite. Instead, hafnian zircon intergrown with abundant thorian coffinite becomes abundant in the lepidolite core, indicating a transition of Zr + Hf from octahedral sites in the oxide minerals to the much more common 8-fold coordination in the orthosilicate; this shift implies a transition from relatively alkaline to more acidic conditions.
