The evaporitic and carbonate facies at the Triasssic-Jurassic transition in Morata de Jalón (Zaragoza): tectonicsedimentationrelationship

摘要

Facies analysis and geological mapping of the Triassic-Jurassic transition units (Cor tes de Tajuña and LéceraFms) exposed in an area of 10 km2 around Morata de Jalón locality (Zaragoza province, North IberianRange) allow the definition of two sedimentar y episodes controlled by normal faulting. During episode 1,a subsident coastal salina filled with Ca-sulphates was formed in the downthrown block of two normalfaults. Erosion of the Upper Triassic units (Keuper facies and Imón Fm) and deposition of terrestrial facies(lutites, sandstones and polymict breccias), took place in the uplifted blocks. During episode 2, tectonicreactivation combined to long-term sea level rise, resulted in the setting of tidal flat facies, preserved asdolomitic breccias, cellular limestones and finelly-crystalline limestones. Deposition of shallow subtidalfacies (mudstones and oolitic-peloidal and bioclastic packstones-grainstones) was favoured in the moresubsident areas of downthrown blocks. Cracking and fracturing of the early lithified subtidal carbonatesalso originated the local deposition in these areas of calcareous breccias and rudites