Mineralogy and water chemistry of the Lake Acigol, Denizli, Turkey

Lake Acigol of Turkey is a perennial lake with a brine composition of Na-Cl -SO4. The lake is fed mainly by two distinct water sources. The first is gr oundwater of Mg-HCO, type and springs of Na-SO, type. The difference in com position of inflow waters is attributed to different ways of water cycling. Ephemeral mudflats around Lake Acigol are composed of gypsum, calcite, dol omite, huntite, together with elastic minerals. Brine-soaked mudflat exist locally and contain efflorescence of halite, bloedite; thenardite and/or mi rabilite precipitating from the artesian groundwater; Dominance of aragonit e and high TOC values recorded in the gel-like lake sediments are the indic ator of bacterial activity in the lake. Fluid-mineral equilibria calculatio ns performed on the waters of the Lake Acigol basin successfully predicted precipitation of minerals detected in the recent sediments.