MINERALOGICAL, CHEMICAL AND MORPHOLOGICAL FEATURES OF SALT ACCUMULATIONS IN THE FLUMEN-MONEGROS DISTRICT, NE SPAIN

Relationships among the mineralogy, morphology and the formation proce sses of salt accumulations were studied in three sampling areas in the Flumen-Monegros district, which represent three geochemical environme nts [Na-SO4-Cl, Na-(Mg)-SO4-Cl and Na-CO3SO4-Cl], according to chemica l and mineralogical results. The samples included both natural ones an d others that were obtained in the laboratory by the crystallization o f brines with and without substrate. A climatic chamber was used to re produce the environmental conditions. Laboratory crystallization of br ines without soil substrate does not always reproduce the natural mine ral associations. Such associations were reproduced, however, when the crystallization was carried out with the epipedon. New morphologies a re described for bloedite (radiating prismatic, and foliated rosette-l ike) and burkeite (book plates and spheroidal association of plates), the latter formed through capillary evaporation. X-ray diffraction, sc anning electron microscopy (SE and BSE modes), energy dispersive X-ray spectrometry and polarized light microscopy were some of the techniqu es used, supplemented by chemical data.