Other than just the number of grains, are detrital zircons mounted differently than igneous/metamorphic samples?
Actually, there is a slight difference. Igneous and metamorphic zircons are hand-picked with tweezers or a needle and are carefully aligned on the tape. This is simple for only 20-40 grains. Grains are typically placed about one grain widths spacing apart. In contrast, detrital grains, if the separate is clean, can just be poured onto the tape through a mask and gently spread throughout the row with a clean fingertip. By not hand-picking detrital zircons, no picking bias is introduced to the sample and the laborious task of hand-picking 100+ grains is also avoided. Using this technique, detrital grains are often almost touching in a sample row.
