* Data are normalized to 100 wt% on a water-free basis; SD, standard deviation; averages include zero values; n, number of analyses; FeOt, total Fe as FeO; H2Odiff, water by difference. Standardization by mineral and glass
standards *5701: Summary of trace-element geochemistry (ppm) of Aniakchak, 5.8 ka, 3.1 ka, and 0.4 ka tephra beds