Zuni Salt Lake is a shallow saline lake in a maar in west-central New Mexico. The basin was formed during the late Pleistocene when volcanic and phreatic explosions punctured Paleozoic and Mesozoic strata. The lake is supported by runoff and saline springs (specific gravity 1.010 to 1.130), which rise along fractures in the volcanic conduits underlying the maar and apparently dissolve salt from the Permian Supai Formation.
Two cinder cones occupy the center of the maar. The larger has a crater containing a pool of saline water (specific gravity 1.080) that is sometimes meromictic.
Dominant organisms of Zuni Salt Lake and the Cinder Cone Pool are Artemia salina and Hydropyrus hians. The bottom of the pool is covered with a blue-green algal mat of Anacystis sp.
Sediments in Zuni Salt Lake consist of salt crusts (halite, calcite, and gypsum) inter-bedded with layers of clay and organic matter. The sediments of the pool are watery sapropel, algal material, calcite, and gypsum.
Fluctuations of the chemistry, physics, and biology of these aquatic environments are extreme because of sporadic but torrential rainfall entering the shallow lakes in late summer and early fall.