Calcretes have been recognized in the bottom of a palaeokarstic sinkhole etched into Early
Jurassic carbonates from the Subbetic (Southern Spain). These are 3 to 10 cm thick and
they show an internal structure in which three units can be distinguished. The lower unit is
composed of alternate irregular bands of unfossiliferous micrite and sparry calcite. In the
micrite, several features point out the activity of endolithic microorganisms as fungi and
bacteria. The middle unit, which has a laminated structure with palisade calcite spar and …