Sedimentación lacustre (Carbonatado-salina) en las facies autuniense de la Cordillera Ibérica

Abstract

The aim of this paper is the better understanding of the carbonate and evaporite sedimentation of the upper unit of the Autunian facies in the "Sierra de Aragoncillo". Also the diagenetic evolution of these sediments in their reactions with the interbedded ryolitic-dacitic tuffs and ashes, have reen studied. The petrographic features of these carbonates are indicative of an early process of dolomitization in a hypersaline environment. The source of magnesium could be the sorroun ding volcanic rocks close to the lacustrine basin. Other common diagenetic minerals are: Zeolites, K-feldspar, quartz and clay minerals. The authigenesis of these minerals are reported to be the result of the reaction of tuffaceous rocks with interstitial waters trapped during sedimentation in a saline-alkaline lake.
Considering the above data, we can establish that the lacustrine sedimentation at the end ofthe Autunian took place in a closed basin with arid climate.