Penecontemporaneous diagenesis in continental saline sediments: bloeditization in Quero playa lake (La Mancha, Central Spain)

In most continental saline lakes of La Mancha (Central Spain) bloedite has been identified as a part of recent saline deposits. By means of a monitoring of the natural evaporation process of the brines in the Quero playa lake has been observed, the absence of this mineral as a primary phase in the sequence of saline precipitation. However, bloedite appears as one of the major components of the saline deposit originated during the aforementioned evaporation period. The genesis of this bloedite is caused by a syndepositional diagenetic process we have called `bloeditizationʹ. This process in an early rapid diagenetic genesis of bloedite, as a result of the reaction between the previously precipitated epsomite and the concentrating brines. The replacement of the epsomite by bloedite, leads to the release of magnesium chloride and water into the brine. If we use a polythermal thermodynamic simulation of the studied evaporation process, we obtain results consistent with observations of the brine precipitation paths and the mineralogical composition of the saline deposit.