A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Géodynamique andine : résumé étendus = Andean geodynamics : extended abstracts

Le Salar Grande est le seul bassin évaporitique cénozoïque localisé dans la Cordillère côtière au N du Chili. Il est placé dans une dépression tectonique de plus de 50 km de long et de direction N-S, qui est contrôlée par la faille d'Atacama. La dépression est remplie d'une roche halitique, très pure, dont l'épaisseur dépasse localement 100 mètres. La texture de la halite permet de distinguer deux unités : la halite litée inférieure, qui présente des cycles centimétriques avec des structures en chevron, et la halite massive supérieure, avec des cristaux plus grossiers, générés par un processus de croissance interstitielle. Un autre type de halite, avec des cristaux de grande taille (parfois métrique), remplit les cavités de dissolution de la halite plus ancienne. A partir des observations des textures halitiques, de la distribution des minéraux accessoires, de la distribution et des rapports des traces métalliques, et de la composition des saumures piégées dans les inclusions fluides, on peut reconstituer les détails de l'évolution sédimentaire et diagénétique du salar, et obtenir indirectement des informations paléogéographiques et paléoclimatiques. (Résumé d'auteur

The Messinian salt of the Mediterranean: geochemical study of the salt from the Central Sicily Basin and comparison with the Lorca basin (Spain)

A geochemical study has been performed on Messinian halite deposits fi om the Central Sicily Basin and the results compared with those published for the Lorca Basin (Spain), in order to provide a depositional model for these marine salt formations and to improve our understanding of the Messinian evaporitic event. Halite samples from boreholes and mine galleries from the Salt Member of the Gessoso Solfifera Formation of the Caltanissetta Basin (Sicily) were studied petrographically and geochemically. The bromine content of halite increases from the base of the Salt Member to the horizons containing kainite (layer B) up to 150 ppm. Upwards, the bromine content decreases and at the top of the member it drops down below 13 ppm. thus reflecting a marked dilution of the mother brine, which resulted in the precipitation of almost bromine-free salt. This dilution has been attributed to the inflow of continental waters in the literature. Fluid inclusion compositions at the top of the unit demonstrate the SO4-rich character of the brine, which is only slightly depleted in SO4 with respect to normal evaporated seawater and shows a significantly Mg and K content, indicating the marine origin of the brine which controlled the final precipitation. This is in agreement with the petrographically well-established primary origin of kainite. In the case of the Saline Unit from the Lorca Basin (SE Spain), bromine profiles are essentially similar to those described above, whereas fluid inclusion compositions at the top of the unit reveal the Mg, K and SO4-poor character of the brine and reflect an inflow of continental waters into the basin which were responsible for final dilution and bromine-free salt precipitation. Thus, in the Lorca basin, which occupied a marginal position in the Mediterranean Basin, dilution and salt reprecipitation at the top of the salt unit occurred when the basin was cut off from the sea and became completely isolated and desiccated. In the Caltanissetta basin, which occupied a relatively more central position, similar saline sediments were formed al the top of the Salt Member as a result of fresh marine waters inputs. Accordingly, in the Sicilian basin, the existing unconformity at the top of the Lower Evaporite Unit does not imply subaerial exposure or complete desiccation of the marine basin. Local tectonism probably controlled the different hydrochemical evolutions of these basins