The processes by which trace metals such as FE, Mn, Cu, Pb, Zn, Mo, V, Cd and Co are incorporated into organic-rich sediments of saline lakes will be elucidated by studying three contrasting closed basins: Great Salt Lake, Utah, Mono Lake, Cal. and Walker Lake, Nevada. Great Salt Lake bottom waters are anoxic and consist of concentrated sulfate enriched brines, Mono Lake is highly productive and alkaline, with carbonate-enriched brines and an anoxic sediment sulfate. Walker Lake is alkaline, but less concentrated and less productive, and its sediment-water interface is only temporarily anoxic. Lake waters, pore fluids and sediment to 1 meter depth are to be analyzed and studied with special emphasis on metal complexing by organic matter, such as humic substances. Preliminary data suggest that at Great Salt Lake metals are precipitated as sulfides in the hypolimnion. At Mono Lake, metals are mobilized very near the sediment surface. Within the sediment, hydrogen sulfide production is high and metals are precipitated. At Walker Lake, an oxy-hydroxyde layer is formed at the sediment-water interface. A molybdenum maximum exists in the pore fluids at 10 cm and in the sediments at 15 cm depth, indicating considerable metal redistribution in response to redox changes. A comparison of metal distribution between lake waters, pore fluids and sediment in these three contrasting sites promises to provide significant insights into metal accumulation in black shles and oil shales deposited in saline lacustrine settings.
