A schematic illustration and pictures of the sample holder. Upper left: a picture of the top view of the sample holder. An Au disk, φ3-mm and 0.3-mm thick, is fixed onto an Al-stub holder. Lower left: a schematic illustration of the side view of the sample holder. Right: an enlarged view of the Au disk. The sample was pressed and fixed at the center of the disk. Standards for isotopic analysis by NanoSIMS were also fixed near the edge of the Au disk and are marked in the figure.