Trace-element compositions for sediment samples were determined by ALS Geochemistry method ME-MS61: Four-acid digestion followed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma-mass spectroscopy (ICP-MS). Platinum, palladium, and gold values were analyzed by 30 g fire assay with ICP-MS finish (ALS Geochemistry method PGM-MS23). Samples that exceeded detection limits for gold were reanalyzed by 30 g fire assay with atomic absorption (AA) finish (ALS Geochemistry method Au-AA25).