RT Journal Article
T1 Biosedimentary and geochemical constraints on the precipitation of mineral crusts in shallow sulphate lakes
A1 Cabestrero Aranda, Óscar
A1 Del Buey Fernández, Pablo
A1 Sanz Montero, María Esther
AB Seasonal desiccation of Mg2+–(Na+)–(Ca2+)–SO42−–(Cl−) saline lakes in La Mancha (Central Spain) that host microbial mats led to the precipitation of hydrated Na-Mg sulphates and gypsum. Sulphates precipitated in the submerged conditions form extensive biolaminites, whilst in marginal areas they produce thin crusts. Sedimentological, mineralogical, petrographic and high resolution textural studies reveal that the crusts were formed within the benthic microbial mats that thrive at salinities ranging from 160 to 340 g·L−1. The minerals of the crusts are primary bloedite (Na2Mg(SO4)2·4H2O), epsomite (MgSO4·7H2O), gypsum (CaSO4·2H2O) and mirabilite (Na2SO4·10H2O), as well as secondary hexahydrite (MgSO4·6H2O) and thenardite (Na2SO4). Primary bloedite crystals, which form the framework of surficial and submerged crusts are seen to nucleate subaqueously and grow incorporatively within the matgrounds. Displacive and incorporative epsomite grows on previous bloedite crystals and also on the ground. Mirabilite is precipitated rapidly at the brine-air interface over bloedite and epsomite. Hexahydrite and thenardite are formed due to dehydration of epsomite and mirabilite, respectively.
PB Elsevier
SN 0037-0738
YR 2018
FD 2018
LK https://hdl.handle.net/20.500.14352/12086
UL https://hdl.handle.net/20.500.14352/12086
LA eng
NO Ministerio de Economía y Competitividad (MINECO)/FEDER
NO Universidad Complutense de Madrid
DS Docta Complutense
RD 18 abr 2025